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コミュニケーション情報 byコメンテータガイド

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  黄砂、森林火災煤煙、工場煤煙などに代表される大気エアロゾルに関する研究を、宇宙から（人工衛星）、地上から行っております。

研究者情報

学位

• 博士（工学）（金沢工業大学）

ホームページURL

https://jglobal.jst.go.jp/detail?JGLOBAL_ID=201401016617824835

J-Global ID

• 201401016617824835

研究キーワード

• 光散乱   偏光   エアロゾル   リモートセンシング   SGLI   AERONET   SKYNET   PM2.5   光散乱シミュレーション   エアロゾル光学特性   

現在の研究分野（キーワード）

黄砂、森林火災煤煙、工場煤煙などに代表される大気エアロゾルに関する研究を、宇宙から（人工衛星）、地上から行っております。

研究分野

• 環境・農学 / 環境動態解析
• 自然科学一般 / 大気水圏科学

経歴

• 2011年04月 - 現在  近畿大学理工(情報;2022~)学部教授
• 2005年04月 - 2011年03月  近畿大学理工学部助(准)教授
• 1998年04月 - 2005年03月  近畿大学理工学部講師
• 1992年04月 - 1998年03月  近畿大学理工学部助手

研究活動情報

論文

• エアロゾル集中観測DRAGON/J-ALPSを終えて

  向井苑生; 佐野 到; 中田真木子; Brent N. Holben; AERONET group; 今須 良一; 岡本 渉; 梶野 瑞王; 小林 拓; 齊藤 保典; 佐藤 陽祐; 清水; 高見 昭; 中口 譲; 西 典宏; 朴 虎東; 藤戸 俊行; 松見 豊; 溝渕 昭二; 宮原 裕一; 森山達天喜

  エアロゾル研究 37 2 136 - 144 日本エアロゾル学会 2022年06月 [査読有り]
  
• Characterization of Wildfire Smoke over Complex Terrain Using Satellite Observations, Ground-Based Observations, and Meteorological Models

  Makiko Nakata; Itaru Sano; Sonoyo Mukai; Alexander Kokhanovsky

  Remote Sensing 14 10 2344 - 2344 2022年05月 [査読有り]
   

  The severity of wildfires is increasing globally. In this study, we used data from the Global Change Observation Mission-Climate/Second-generation Global Imager (GCOM-C/SGLI) to characterize the biomass burning aerosols that are generated by large-scale wildfires. We used data from the September 2020 wildfires in western North America. The target area had a complex topography, comprising a basin among high mountains along a coastal region. The SGLI was essential for dealing with the complex topographical changes in terrain that we encountered, as it contains 19 polarization channels ranging from near ultraviolet (380 nm and 412 nm) to thermal infrared (red at 674 nm and near-infrared at 869 nm) and has a fine spatial resolution (1 km). The SGLI also proved to be efficient in the radiative transfer simulations of severe wildfires through the mutual use of polarization and radiance. We used a regional numerical model SCALE (Scalable Computing for Advanced Library and Environment) to account for variations in meteorological conditions and/or topography. Ground-based aerosol measurements in the target area were sourced from the National Aeronautics and Space Administration-Aerosol Robotic Network; currently, official satellite products typically do not provide the aerosol properties for very optically thick cases of wildfires. This paper used satellite observations, ground-based observations, and a meteorological model to define an algorithm for retrieving the aerosol properties caused by severe wildfire events.
• A study on the impact of mountainous terrain on transboundary and local pollution

  Makiko Nakata; Itaru Sano; Sonoyo Mukai; Souichiro Hioki

  REMOTE SENSING OF CLOUDS AND THE ATMOSPHERE XXVII 12265 2022年 

  The area around the Japanese Alps, which is the focus of this study, is located at the center of Japan's main island and surrounded by mountains with multiple basins. Here, we investigated the effect of mountains on aerosol blocking with respect to transboundary pollution and estimated the effect of the mountain source with respect to local pollution using observations and simulations. A regional chemical transport model was employed for the study. To investigate the effect of mountains, simulations were conducted with and without mountains. From the results of these simulations, we estimated the mountain effects. The presence of mountains was found to increase or decrease aerosol concentration in some cases. However, when averaged over the simulation period, the results showed that mountains effectively reduce aerosol concentrations. On the days when aerosol concentrations increased due to the mountain effect, meteorological conditions with high local emissions and the basin effect acted synergistically to accelerate the increase in aerosol concentrations.
• Improved Algorithms for Remote Sensing-Based Aerosol Retrieval during Extreme Biomass Burning Events

  Sonoyo Mukai; Itaru Sano; Makiko Nakata

  Atmosphere 12 3 403 - 403 2021年03月 [査読有り]
   

  This study proposed an aerosol characterization process using satellites for severe biomass burning events. In general, these severely hazy cases are labeled as “undecided” or “hazy.” Because atmospheric aerosols are significantly affected by factors such as air quality, global climate change, local environmental risk, and human and biological health, efficient and accurate algorithms for aerosol retrieval are required for global satellite data processing. Our previous classification of aerosol types was based primarily on near-ultraviolet (UV) data, which facilitated subsequent aerosol retrieval. In this study, algorithms for aerosol classification were expanded to events with serious biomass burning aerosols (SBBAs). Once a biomass burning event is identified, the appropriate radiation simulation method can be applied to characterize the SBBAs. The second-generation global imager (SGLI) on board the Japanese mission JAXA/Global Change Observation Mission-Climate contains 19 channels, including red (674 nm) and near-infrared (869 nm) polarization channels with a high resolution of 1 km. Using the large-scale wildfires in Kalimantan, Indonesia in 2019 as an example, the complementarity between the polarization information and the nonpolarized radiance measurements from the SGLI was demonstrated to be effective in radiation simulations for biomass burning aerosol retrieval. The retrieved results were verified using NASA/AERONET ground-based measurements, and then compared against JAXA/SGLI/L2-version-1 products, and JMA/Himawari-8/AHI observations.
• Characteristics of aerosol distribution in mountainous regions obtained from AERONET/DRAGON/J-ALPS

  Makiko Nakata; Itaru Sano; Sonoyo Mukai

  REMOTE SENSING OF CLOUDS AND THE ATMOSPHERE XXVI 11859 2021年 

  In order to investigate atmospheric aerosol properties in the mountainous regions of Japan, aerosol observations by the NASA/AERONET field campaign were conducted around Nagano prefecture in Japan since March 2020. This field campaign is called DRAGON/J-ALPS because the target area includes the mountains known as the Japanese Alps. One of the objectives of DRAGON/J-ALPS is to understand the spatial distribution of aerosol properties in mountainous regions. The aerosol concentration levels in the J-ALPS sites are usually not too high. Possible reasons are low local emissions and aerosol advection blocked by the high mountains. However, there are days when the concentration is higher than usual. One of the reasons for this is the advection of "yellow dust" from the continent. Another factor is the local emissions. The shape of the basin surrounded by mountains and meteorological conditions may also promote the retention of aerosols. This work is expected not only to introduce the results of the J-ALPS, but also to provide insights into aerosol advection and local emission in closed mountain areas.
• Analysis of Factors Affecting PM2.5 Concentration in the Mountainous Areas of Japan Through Ground Observations and Simulations.

  Makiko Nakata; Tatsuaki Moriyama; Itaru Sano; Sonoyo Mukai

  IEEE International Geoscience and Remote Sensing Symposium(IGARSS) 7248 - 7251 2021年
• Algorithms for Aerosol Retrieval from Heavy Biomass Burning with Mutual Use of Radiance and Polarization Observations By SGLI.

  Sonoyo Mukai; Itaru Sano; Makiko Nakata

  IEEE International Geoscience and Remote Sensing Symposium(IGARSS) 7204 - 7207 2021年
• SYNERGETIC OBSERVATIONS BY GROUND-BASED AND SPACE LIDAR SYSTEMS AND AERONET SUN-RADIOMETERS: A STEP TO ADVANCED REGIONAL MONITORING OF LARGE SCALE AEROSOL CHANGES

  Anatoli Chaikovsky; Andrey Bril; Oleg Dubovik; Anton Fedarenka; Philippe Goloub; Qiaoyun Hu; Anton Lopatin; Tatyana Lapyonok; Natallia Miatselskaya; Benjamin Torres; David Fuertes; Vladislau Peshcharankou; Thierry Podvin; Ioana Popovici; Dong Liu; Zhengqiang Li; Ourania Soupiona; Maria Mylonaki; Lucia Mona; Aldo Giunta; Nikolaos Papagiannopoulos; Maria Rita Perrone; Salvatore Romano; Dimitris Balis; Nikolaos Siomos; Kalliopi-Artemis Voudouri; Livio Belegante; Doina Nicolae; Dragos Ene; Nicolae Ajtai; Horatiu Stefanie; Vassilis Amiridis; Alexandra Tsekeri; Daniele Bortoli; Maria Joao Costa; Ina Mattis; Francesc Rocadenbosch; Alejandro Rodriguez-Gomez; Michael Sicard; Alfonso J. Fernandez; Francisco Molero; Dietrich Althausen; Holger Baars; Juan Luis Guerrero Rascado; Pablo Ortiz-Amezcua; Jose Antonio Benavent Oltra; Andres Esteban Bedoya-Velasquez; Roberto Roman; Lucas Alados-Arboledas; Yurii Balin; Grigorii Kokhanenko; Ivan Penner; Boris Chen; Leonid Sverdlik; Genadi Milinevsky; Nobuo Sugimoto; Atsushi Shimizu; Tomoaki Nishizawa; Rei Kudo; Itaru Sano; Teppei J. Yasunari; Hitoshi Irie; Toshihiko Takemura; Sang-Woo Kim; Nguyen Xuan Anh; Pham Xuan Thanh; Aleksander Pietruczuk; Iwona S. Stachlewska; Alessia Sannino; Xuan Wang; Antonela Boselli

  29TH INTERNATIONAL LASER RADAR CONFERENCE (ILRC 29) 237 2020年 

  The paper presents the preliminary results of the lidar&radiometer measurement campaign (LRMC2017), estimation of statistical relations between aerosol mode concentrations retrieved from CALIOP and ground-based lidar stations and case study of fire smoke events in the Eurasian regions using combined ground-based and space lidar and radiometer observations.
• Algorithms for the classification and characterization of aerosols: utility verification of near-UV satellite observations

  Sonoyo Mukai; Itaru Sano; Makiko Nakata

  Journal of Applied Remote Sensing 31 1 014527-1 - 014527-20 2019年03月 [査読有り]
   

  Aerosol types were characterized and classified using multispectral satellite data. The role of near-UV data in the detection of absorbing aerosols, such as biomass burning aerosols (BBA) or mineral dust particles (DUST), was examined on a global scale. An absorbing aerosol index (AAI) was proposed and defined as the ratio of the satellite-observed radiance (R) at a wavelength of 0.412 mu m [R (0.412)] to that at 0.380 mu m [R (0.380)] that can also detect nonabsorbing-type aerosols. Initially, the numerical AAI values were estimated for the BBAs and DUST from measurements collected by the Advanced Earth Observing Satellite-2/Global Imager (ADEOS-2/GLI). The Japanese short mission ADEOS-2 carried the GLI instrument with observation channels in the near-UV region. Not only the AAI index but also the short-wavelength infrared measurements were utilized to determine the dust detection index (DDI) defined as the ratio of R (2.210) to R (0.380) in order to discriminate BBAs from DUST. In addition, the AAI and DDI values were evaluated for the detection of clouds. The results allowed the classification criteria for DUST, BBA, other types of aerosols and clouds to be obtained. The Second-Generation Global Imager (SGLI) sensor is onboard the Japanese Global Change Observation Mission-Climate (GCOM-C) (SHIKISAI in Japanese) satellite launched on December 23, 2017. The SGLI has multiple channels (19) including near-UV and polarization sensors in the red and near-IR wavelengths. We also demonstrated the advantages of the SGLI for near-UV and polarization data for aerosol remote sensing. An understanding of aerosol types facilitated subsequent aerosol retrieval. Then, retrieval for classified aerosols was made based on the radiation simulations with multispectral radiance by GLI and polarization measurements by Polarization and Directionality of the Earth's Reflectances (POLDER)-2, respectively, mounted on the ADEOS-2 satellite. The proposed algorithms are expected to be available not only for the analysis of the SGLI data but also for other future missions. (C) The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License.
• Polarimetric remote sensing of atmospheric aerosols: instruments, methodologies, results, and perspectives

  Dubovik, O; Z. Li; M.I. Mishchenko; D. Tanré; Y. Karol; B. Bojkov; B. Cairns; D.J. Diner; W.R. Espinosa; P. Goloub; X. Gu; O. Hasekamp; J. Hong; W. Hou; K.D. Knobelspiesse; J. Landgraf; L. Li; P. Litvinov; Y. Liu; A. Lopatin; T. Marbach; H. Maring; V. Martins; Y. Meijer; G. Milinevsky; S. Mukai; F. Parol; Y. Qiao; L. Remer; J. Rietjens; I. Sano; P. Stammes; S. Stamnes; X. Sun; P. Tabary; L.D. Travis; F. Waquet; F. Xu; C. Yan; D. Yin

  J. Quant. Spectrosc. Radiat. Transfer 224 474 - 511 2019年02月 [査読有り]
  
• Observations of the Interaction and Transport of Fine Mode Aerosols With Cloud and/or Fog in Northeast Asia From Aerosol Robotic Network and Satellite Remote Sensing

  T. F. Eck; B. N. Holben; J. S. Reid; P. Xian; D. M. Giles; A. Sinyuk; A. Smirnov; J. S. Schafer; I. Slutsker; J. Kim; J. H. Koo; M. Choi; K. C. Kim; I. Sano; A. Arola; A. M. Sayer; R. C. Levy; L. A. Munchak; N. T. O'Neill; A. Lyapustin; N. C. Hsu; C. A. Randles; A. M. Da Silva; V. Buchard; R. C. Govindaraju; E. Hyer; J. H. Crawford; P. Wang; X. Xia

  Journal of Geophysical Research: Atmospheres 123 10 5560 - 5587 2018年05月 [査読有り]
   

  Analysis of Sun photometer measured and satellite retrieved aerosol optical depth (AOD) data has shown that major aerosol pollution events with very high fine mode AOD (> 1.0 in midvisible) in the China/Korea/Japan region are often observed to be associated with significant cloud cover. This makes remote sensing of these events difficult even for high temporal resolution Sun photometer measurements. Possible physical mechanisms for these events that have high AOD include a combination of aerosol humidification, cloud processing, and meteorological covariation with atmospheric stability and convergence. The new development of Aerosol Robotic Network Version 3 Level 2 AOD with improved cloud screening algorithms now allow for unprecedented ability to monitor these extreme fine mode pollution events. Further, the spectral deconvolution algorithm (SDA) applied to Level 1 data (L1 no cloud screening) provides an even more comprehensive assessment of fine mode AOD than L2 in current and previous data versions. Studying the 2012 winter-summer period, comparisons of Aerosol Robotic Network L1 SDA daily average fine mode AOD data showed that Moderate Resolution Imaging Spectroradiometer satellite remote sensing of AOD often did not retrieve and/or identify some of the highest fine mode AOD events in this region. Also, compared to models that include data assimilation of satellite retrieved AOD, the L1 SDA fine mode AOD was significantly higher in magnitude, particularly for the highest AOD events that were often associated with significant cloudiness.
• An overview of mesoscale aerosol processes, comparisons, and validation studies from DRAGON networks

  Brent N. Holben; Jhoon Kim; Itaru Sano; Sonoyo Mukai; Thomas F. Eck; David M. Giles; Joel S. Schafer; Aliaksandr Sinyuk; Ilya Slutsker; Alexander Smirnov; Mikhail Sorokin; Bruce E. Anderson; Huizheng Che; Myungje Choi; James H. Crawford; Richard A. Ferrare; Michael J. Garay; Ukkyo Jeong; Mijin Kim; Woogyung Kim; Nichola Knox; Zhengqiang Li; Hwee S. Lim; Yang Liu; Hal Maring; Makiko Nakata; Kenneth E. Pickering; Stuart Piketh; Jens Redemann; Jeffrey S. Reid; Santo Salinas; Sora Seo; Fuyi Tan; Sachchida N. Tripathi; Owen B. Toon; Qingyang Xiao

  Atmospheric Chemistry and Physics 18 2 655 - 671 2018年01月 [査読有り]
   

  Over the past 24 years, the AErosol RObotic NETwork (AERONET) program has provided highly accurate remote-sensing characterization of aerosol optical and physical properties for an increasingly extensive geographic distribution including all continents and many oceanic island and coastal sites. The measurements and retrievals from the AERONET global network have addressed satellite and model validation needs very well, but there have been challenges in making comparisons to similar parameters from in situ surface and airborne measurements. Additionally, with improved spatial and temporal satellite remote sensing of aerosols, there is a need for higher spatial-resolution ground-based remote-sensing networks. An effort to address these needs resulted in a number of field campaign networks called Distributed Regional Aerosol Gridded Observation Networks (DRAGONs) that were designed to provide a database for in situ and remote-sensing comparison and analysis of local to mesoscale variability in aerosol properties. This paper describes the DRAGON deployments that will continue to contribute to the growing body of research related to meso- and microscale aerosol features and processes. The research presented in this special issue illustrates the diversity of topics that has resulted from the application of data from these networks.
• Depolarization ratios retrieved by AERONET sun-sky radiometer data and comparison to depolarization ratios measured with lidar

  Youngmin Noh; Detlef Muller; Kyunghwa Lee; Kwanchul Kim; Kwonho Lee; Atsushi Shimizu; Sang-Woo Kim; Itaru Sano; Chan Bong Park

  ATMOSPHERIC CHEMISTRY AND PHYSICS 17 10 6271 - 6290 2017年05月 [査読有り]
   

  The linear particle depolarization ratios at 440, 675, 870, and 1020 nm were derived using data taken with the AERONET sun-sky radiometer at Seoul (37.45 degrees N, 126.95 degrees E), Kongju (36.47 degrees N, 127.14 degrees E), Gosan (33.29 degrees N, 126.16 degrees E), and Osaka (34.65 degrees N, 135.59 degrees E). The results are compared to the linear particle depolarization ratio measured by lidar at 532 nm. The correlation coefficient R-2 between the linear particle depolarization ratio derived by AERONET data at 1020 nm and the linear particle depolarization ratio measured with lidar at 532 nm is 0.90, 0.92, 0.79, and 0.89 at Seoul, Kongju, Gosan, and Osaka, respectively. The correlation coefficients between the lidar-measured depolarization ratio at 532 nm and that retrieved by AERONET at 870 nm are 0.89, 0.92, 0.76, and 0.88 at Seoul, Kongju, Gosan, and Osaka, respectively. The correlation coefficients for the data taken at 675 nm are lower than the correlation coefficients at 870 and 1020 nm, respectively. Values are 0.81, 0.90, 0.64, and 0.81 at Seoul, Kongju, Gosan, and Osaka, respectively. The lowest correlation values are found for the AERONET-derived linear particle depolarization ratio at 440 nm, i.e., 0.38, 0.62, 0.26, and 0.28 at Seoul, Kongju, Gosan, and Osaka, respectively. We should expect a higher correlation between lidar-measured linear particle depolarization ratios at 532 nm and the ones derived from AERONET at 675 and 440 nm as the lidar wavelength is between the two AERONET wavelengths. We cannot currently explain why we find better correlation between lidar and AERONET linear particle depolarization ratios for the case that the AERONET wavelengths (675, 870, and 1020 nm) are significantly larger than the lidar measurement wavelength (532 nm). The linear particle depolarization ratio can be used as a parameter to obtain insight into the variation of optical and microphysical properties of dust when it is mixed with anthropogenic pollution particles. The single-scattering albedo increases with increasing measurement wavelength for low linear particle depolarization ratios, which indicates a high share of fine-mode anthropogenic pollution. In contrast, single-scattering albedo increases with increasing wavelength for high linear particle depolarization ratios, which indicated a high share of coarse-mode mineral dust particles. The retrieved volume particle size distributions are dominated by the fine-mode fraction if linear particle depolarization ratios are less than 0.15 at 532 nm. The fine-mode fraction of the size distributions decreases and the coarse-mode fraction of the size distribution increases for increasing linear particle depolarization ratio at 1020 nm. The dust ratio based on using the linear particle depolarization ratio derived from AERONET data is 0.12 to 0.17. These values are lower than the coarse-mode fraction derived from the volume concentrations of particle size distributions, in which case we can compute the coarse-mode fraction of dust.
• An effective method for retrieval of three kinds of aerosol properties focusing on a coming GCOM-C1 / SGLI in December of 2017

  Itaru Sano; Sonoyo Mukai; Makiko Nakata

  Proceedings of SPIE - The International Society for Optical Engineering 10424 2017年 

  This work describes an algorithm for aerosol retrieval focusing on the second global imager (SGLI) mounted on the forthcoming global change observation mission - 1st climate satellite (GCOM-C1). The SGLI has a function to measure semi-Stokes components (I, Q, and U) of the Earth's reflectances at red (678 nm) and near infrared (868 nm) with large tilting angle (±45 deg.) along track direction. The SGLI also measures total reflectance from nadir looking position from near UV (380 nm) to far infrared (12 μm). The aerosol retrieval algorithm for the SGLI uses two-channel polarization information from slant path direction as well as nadir looking reflectance at blue channel (443 nm) to estimate aerosol optical thickness, Ångström exponent, and single scattering albedo of particles. The algorithm is tested by the polarization and directionality of the Earth's reflectances (POLDER) measurements.
• Regional and local variations in atmospheric aerosols using ground-based sun photometry during Distributed Regional Aerosol Gridded Observation Networks (DRAGON) in 2012

  Itaru Sano; Sonoyo Mukai; Makiko Nakata; Brent N. Holben

  ATMOSPHERIC CHEMISTRY AND PHYSICS 16 22 14795 - 14803 2016年11月 [査読有り]
   

  Aerosol mass concentrations are affected by local emissions as well as long-range transboundary (LRT) aerosols. This work investigates regional and local variations of aerosols based on Distributed Regional Aerosol Gridded Observation Networks (DRAGON). We constructed DRAGON-Japan and DRAGON-Osaka in spring of 2012. The former network covers almost all of Japan in order to obtain aerosol information in regional scale over Japanese islands. It was determined from the DRAGON-Japan campaign that the values of aerosol optical thickness (AOT) decrease from west to east during an aerosol episode. In fact, the highest AOT was recorded at Fukue Island at the western end of the network, and the value was much higher than that of urban areas. The latter network (DRAGON-Osaka) was set as a dense instrument network in the megalopolis of Osaka, with a population of 12 million, to better understand local aerosol dynamics in urban areas. AOT was further measured with a mobile sun photometer attached to a car. This transect information showed that aerosol concentrations rapidly changed in time and space together when most of the Osaka area was covered with moderate LRT aerosols. The combined use of the dense instrument network (DRAGON-Osaka) and high-frequency measurements provides the motion of aerosol advection, which coincides with the wind vector around the layer between 700 and 850 hPa as provided by the reanalysis data of the National Centers for Environmental Prediction (NCEP).
• Spatiotemporal variations in atmospheric aerosols in East Asia: Identifying local pollutants and transported Asian aerosols in Osaka, Japan using DRAGON

  Makiko Nakata; Itaru Sano; Sonoyo Mukai; Brent N. Holben

  Atmos. Chem. Phys. Discuss. 2016年04月
• Space-based remote sensing of atmospheric aerosols: The multi-angle spectro-polarimetric frontier

  A.A. Kokhanovsky; A.B. Davis; B. Cairns; O. Dubovik; O.P. Hasekamp; I. Sano; S. Mukai; V.V. Rozanov; P. Litvinov; T. Lapyonok; I.S. Kolomiets; Y.A. Oberemok; S. Savenkov; W. Martin; A. Wasilewski; A. Di Noia; F.A. Stap; J. Rietjens; F. Xu; V. Natraj; M. Duan; T. Cheng; R. Munro

  Earth-Science Reviews 145 85 - 116 2015年06月 [査読有り]
  
• RETRIEVAL FOR PM2.5 DISTRIBUTION FROM SPACE

  Itaru Sano; Sonoyo Mukai; Makiko Nakata

  2015 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS) 2206 - 2209 2015年 

  Concentration of particulate matter (PM2.5) is a good indicator of air pollution by anthropogenic aerosols in particular near surface. However instrumentation of PM2.5 is still on going in East Asia even in Japan. This work intends to develop an algorithm for estimating PM2.5 distribution based on the satellite measurements. Combined use of satellite derived columnar aerosol optical thickness (AOT) and vertical distribution of aerosol extinction by ground-based LIDAR measurements is available for estimation of near surface AOT. Thus the derived correlation between AOT and PM2.5 is utilized to retrieve satellite based PM2.5.
• A study of aerosol pollution episode due to agriculture biomass burning in the east-central China using satellite data

  Sonoyo Mukai; Makiko Nakata; Masayoshi Yasumoto; Itaru Sano; Alexander Kokhanovsky

  FRONTIERS IN ENVIRONMENTAL SCIENCE 3 2015年 [査読有り]
   

  Aerosol distributions in East Asia are complicated owing to both natural factors and human activities. In recent years, influence of yellow sand and biomass burning aerosols generated by agricultural biomass burning (ABB) has been noted upon the severe air pollution episodes. This work intends to make the retrieval algorithm more efficient and to make the aerosol model more tractable as far as heavy air pollution caused by ABB is concerned. Aerosol retrieval in the hazy atmosphere is achieved based on radiation simulation method of successive order of scattering (MSOS) for the moderate resolution imaging spectroradiometer (MODIS) on AQUA data. The retrieved aerosol properties agree well with the ground measurements and numerical model simulations. Multi-angle observations with the polarization and directionality of the Earth's reflectances (POLDER) on the polarization & anisotropy of reflectances for atmospheric sciences coupled with observations from a lidar (PARASOL) are available for aerosol retrieval from a mixture of cloud and haze, and many potential applications of MSOS involving polarization information are expected to be available for cloud as well as aerosol episodes.
• Air pollutants in Osaka (Japan)

  Makiko Nakata; Itaru Sano; Sonoyo Mukai

  FRONTIERS IN ENVIRONMENTAL SCIENCE 3 2015年 [査読有り]
   

  Increasing emission of anthropogenic particles is causing heavy air pollution. This work intends to analyze the air pollution in Osaka. PM is usually used as an indicator of air quality, because high PM concentrations can degrade air quality. Osaka is the second largest metropolitan region of Japan and its air is significantly polluted by anthropogenic particles emitted from vehicles and industry. In this study, seasonal variation of air pollutants in Osaka is investigated using ground observations such as PM sampling, AERONET photometry, and numerical model simulation. Results indicate that PM concentrations are high during spring and summer because of yellow dust events and photochemical reactions, respectively. In addition, the impact of anthropogenic PM around Osaka is significant in summer.
• Interpretive Article 衛星および地上データの統合解析による北京上空大気汚染粒子の解明 (特別号 東アジアにおけるエアロゾルの植物・人間系へのインパクト) -- (東アジアのエアロゾル・大気汚染物質の輸送と広域分布の解明)

  向井 苑生; 佐野 到; 中田 真木子

  エアロゾル研究 29 1 125 - 132 日本エアロゾル学会 2014年02月 [査読有り]
  
• Spatial and temporal variations of atmospheric aerosol in Osaka

  Makiko Nakata; Itaru Sano; Sonoyo Mukai; Brent N. Holben

  Atmosphere 4 2 157 - 168 2013年 [査読有り]
   

  It is well known that the aerosol distribution in Asia is complex due to both the increasing emissions of the anthropogenic aerosols associated with economic growth and the behavior of natural dusts. Therefore, detailed observations of atmospheric particles in Asian urban cities are important. In this work, we focus on the spatial and temporal variations of atmospheric particles around Higashi-Osaka in Japan. Higashi-Osaka is located in the eastern part of Osaka, the second-largest city in Japan, and is famous for small- and medium-sized manufacturing enterprises. For this study, we placed various ground measurement devices around the Higashi-Osaka campus of Kinki University including a Cimel sunphotometer supported by NASA/AERONET (Aerosol robotics network), suspended particulate matter (SPM) sampler and LIDAR (light detection and ranging). Individual particle analyses with a SEM (scanning electron microscope)/EDX (energy-dispersive X-ray analyzer) show the temporal variations of particle properties, such as size, shape and components, during a dust event on 21 March 2010. The simultaneous measurement using a portable sun photometer with AERONET was conducted from April to November 2011. A comparison of the data at each site and the combination of the observed LIDAR data and model simulations indicate the difference in the transportation processes between dust and anthropogenic particles. We suppose this difference is attributed to the differences in the vertical aerosol profiles, where one aerosol is transported over Mount Ikoma and the other is blocked by it. © 2013 by the authors licensee MDPI, Basel, Switzerland.
• Local distribution of PM2.5 concentration over Osaka based on space and ground measurements

  Itaru Sano; Sonoyo Mukai; Makiko Nakata; Nobuo Sugimoto; Brent N. Holben

  Proc. SPIE 8534 2012年 

  work intends to estimate PM2.5 concentration over the mega city of Osaka in Japan based on both satellite and ground measurements. Our work is composed of the following steps. At first the relationship between PM2.5 and aerosol optical thickness (AOT) is derived by using the ground measurements with sun photometer and PM-sampler, respectively. In addition vertical distribution of aerosol particles are also investigated by LIDAR measurements. The second step is to retrieve columnar AOT distribution from the space-based reflectance information with CAI (cloud aerosol imager) on GOSAT (greenhouse gases observing satellite). Note that the PM2.5 measurements indicate the surface level concentration of the atmospheric particles, and hence the columnar AOT distribution should be converted to the surface level aerosol optical depth (AOD) based on the aerosol extinction profile with LIDAR. Finally, PM2.5 distribution is obtained from the relationship derived at the first step. The obtained results of PM2.5 are partially validated with the sampling data of PM2.5 at the surface.
• DRAGON-West Japan campaign in 2012: Regional aerosol measurements over Osaka

  I. Sano; S. Mukai; B. N. Holben; M. Nakata; M. Yonemitsu; N. Sugimoto; T. Fujito; T. Hiraki; N. Iguchi; K. Kozai; M. Kuji; K. Muramatsu; Y. Okada; Y. Okada; Y. Sadanaga; S. Tohno; Y. Toyazaki; K. Yamamoto

  Proc. SPIE 8523 2012年 

  It is known that the aerosol distribution in Asia is complicated due to the increasing emissions of anthropogenic aerosols in association with economic growth and natural dust significantly varied with the seasons. Therefore it is clear that local spatially and temporally resolved measurements of atmospheric aerosols in Asian urban city are necessary. Since Osaka, Kobe, Kyoto, and Nara are located in very close each others (all cities are included in around 70x70 km(2) area). The population of the region is around 13 millions including neighbor prefectures, accordingly air quality in this region is slightly bad in comparison with the remote area. Furthermore, in recent years, Asian dusts and anthropogenic small particles some times transported from China and cover these cities throughout year. DRAGON (Distributed Regional Aerosol Gridded Observation Network) is a project of dense sun/sky radiometer network in the urban area. The DRAGON-West Japan field campaign was performed over Osaka and neighbor cities with 7 AERONET instruments from March to end of May in 2012. As results, DRAGON measurements indicate small differences among the values of AOT over Osaka region.
• Optical properties of biomass burning aerosols during Russian forest fire events in 2010

  Itaru Sano; Sonoyo Mukai; Makiko Nakata; Brent N. Holben; Nobuyuki Kikuchi

  Proc. SPIE 8177 2011年 

  This work intends to develop an algorithm for aerosol retrieval based on the combined use of CAI (Cloud aerosol imager) on the satellite GOSAT and POLDER (Polarization and directionality of Earth's reflectances) on PARASOL. The CAI measures the total intensity at 0.380, 0.674 and 0.870 mu m. The measurements at 0.380 mu m have an advantage for detecting the absorbing aerosols, such as carbonaceous as well as dust aerosols. On the contrary, POLDER provides the multi directional polarization information at 0.670 and 0.865 mu m. The polarization information is useful to retrieve aerosol characteristics over land because the polarization by the land surface is much smaller than the total one. Our algorithm is mainly based on the radiative transfer calculations in the Earth atmosphere model involving various kinds of atmospheric particles. This algorithm is applied for the Russian forest fire events happened in summer of 2010. As results, aerosol optical thickness (AOT), Angstrom exponent and single scattering albedo (SSA) are retrieved. The retrieved results are partially validated with ground based measurements of AERONET. It is found that AOT takes the values of similar to 2 all over the event region and larger than similar to 5 over the plume core. The particle size information retrieved as Angstrom exponent indicates the existence of small aerosols in the plume. The SSA takes the lower value of similar to 0.85, especially lower in the edge of plume than at the plume core. This fact might suggest the changing of particle property by water vapor uptake during transport.
• Suspended particulate matter sampling at an urban AERONET site in Japan, part 2: relationship between column aerosol optical thickness and PM2.5 concentration

  Itaru Sano; Makiko Mukai; Nobukazu Iguchi; Sonoyo Mukai

  JOURNAL OF APPLIED REMOTE SENSING 4 2010年02月 [査読有り]
   

  The concentration of suspended particulate matter smaller than 2.5 mu m (PM2.5) was linearly correlated with the column aerosol optical thickness (AOT) based on simultaneous measurements at a NASA/AERONET station at Kinki University Campus, Higashi-Osaka, Japan, between March 2004 and June 2006. The correlation coefficient differed with the aerosol type, being maximal when PM2.5 values were measured 120 minutes after AOT data for a dust episode, but almost independent of the time difference between measurements for anthropogenic aerosols. The obtained results were validated using data obtained at the Higashi-Osaka and Noto sites. Our results suggest that the PM2.5 mass concentration can be estimated from the AOT, and vice versa, and hence a distribution map of PM2.5 can be produced from the satellite-derived AOT map determined from the Aqua/MODIS sensor.
• 東アジアにおけるダストエアロゾル粒子の検出と解析

  向井 真木子; 佐野 到; 飯塚 卓也; 横前 拓磨; 向井 苑生

  日本リモートセンシング学会誌 = Journal of the Remote Sensing Society of Japan 30 1 1 - 10 社団法人 日本リモートセンシング学会 2010年01月 [査読有り]
   

  It is well known that the heavy soil dust has been transported from the China continent to Japan on westerly winds, especially in spring. The satellite observation is an effective tool for global monitoring of the Asian dust. A new algorithm for detection of Asian dust from space is proposed based on the multispectral satellite data. The derived space-based results are validated with the ground-based measurements and/or model simulations.<BR>The sun/sky photometry has been undertaken at NASA/AERONET stations at Osaka. The suspended particulate matter (SPM) sampling and NIES/LIDAR network equipment have been simultaneously working there. However, it is difficult to relate these ground-based measurements directly to the column space data. Therefore, in order to validate the satellite results with the surface-level data, an aerosol transportation model should be simulated. The measurements are examined with the model simulations.<BR>As a result, the distribution of Asian dust aerosols is retrieved in a comprehensive way in this study.
• Carbonaceous aerosols over Siberia and Indonesia with GOSAT/CAI

  Itaru Sano; Mizuki Tanabe; Takamasa Kamei; Makiko Nakata; Sonoyo Mukai

  Proc. SPIE 7859 2010年 

  Carbonaceous aerosols absorb the visible light, and hence play an important role for climate study. This work intends to develop an algorithm for extracting the optical properties of biomass burning aerosols based on the cloud aerosol imager (CAI) on board greenhouse gases observing satellite (GOSAT). Our algorithm is mainly based on the radiative transfer calculations in the atmosphere involving various kinds of aerosols. This algorithm has been examined for several forest fire events as Siberia in Russia and Kalimantan Island in Indonesia in 2009. As results, aerosol optical thickness (AOT) and single scattering albedo (SSA) at a wavelength 0.55 mu m are retrieved. It is of interest to note that AOT takes the values larger than similar to 2 over Siberia plume, and similar to 5 or more over the plume in Kalimantan of Indonesia, and the values of SSA are low such as similar to 0.8 to similar to 0.9 over core region of the plume. In addition, the AOT results are partially validated by MODIS level-2 products (MYD04).
• Algorithm for aerosol retrieval based on radiance and polarimetry for SGLI

  I. Sano; M. Nakata; S. Mukai; B. N. Holben

  International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives 38 380 - 385 2010年01月 

  Atmospheric aerosols play an important role not only in the climate research but also in the remote sensing of the Earth surface. This work focuses on the retrieval procedure for such aerosol properties as optical thickness, Angstrom exponent and single scattering albedo with the Second Global Imager (SGLI) on Japanese Global Change Observation Mission - Climate satellite (GCOM-C). The SGLI is designed to observe atmosphere, land, and ocean in total by using 18 channels from near ultra violet to thermal infrared spectra. One of the interesting features of SGLI is to measure the polarization of reflectance from Earth with long track tilting angles covering +/-45 degrees. Our algorithm is based on the efficient usage of this polarization information as well as radiance measurements. Namely aerosol optical thickness (AOT) and its wavelength tendency are derived by combination use of polarization and radiance with two-channel algorithm. In addition it is known that the carbonaceous aerosol is an unknown item for climate modelling. Here the retrieval algorithm for carbonaceous particles is especially focused by using the near UV measurements. Our algorithms are validated with the data given by POLDER and GLI sensors equipped on the satellite ADEOS-II.
• SKYNET観測に基づくエアロゾル及び雲の検証システムの構築とADEOS-II/GLIデータを用いた放射収支の推定

  高村 民雄; 竹中 栄晶; 崔 羽; 中島 孝; 日暮 明子; 福田 悟; 菊地 信行; 中島 映至; 佐野 到; PINKER Rachel T

  日本リモートセンシング学会誌 = Journal of the Remote Sensing Society of Japan 29 1 40 - 53 社団法人 日本リモートセンシング学会 2009年01月 [査読有り]
   

  Using ADEOS-II/GLI aerosol and cloud products, downward and upward solar radiation at the surface and at the top of the atmosphere are estimated to study the Earth radiation budget. There is a good agreement in the main features of the global distribution of radiative fluxes as derived from GLI and from Terra/MODIS, yet, some differences can be noticed and need to be explained. In order to evaluate satellite-retrieved parameters that play a role in the Earth radiation budget, an observational network known as SKYNET has been established in Eastern Asia and it has already been operational during the ADEOS-II/GLI launch. Specifically, observations from the newly developed <I>i-</I>sky radiometer have been used for aerosol and cloud product evaluation. The aerosol products have been found to be in good agreement with observations while the cloud products need further evaluation.
• Retrieval Algorithm Based on Combined Use of POLDER and GLI Data for Biomass Aerosols

  SANO Itaru; OKADA Yasuhiko; MUKAI Makiko; MUKAI Sonoyo

  日本リモートセンシング学会誌 = Journal of the Remote Sensing Society of Japan 29 1 54 - 59 一般社団法人 日本リモートセンシング学会 2009年01月 [査読有り]
   

  A procedure for aerosol retrieval by combining data provided by POLDER (Polarization and Directionality of the Earth's Reflectances) and GLI (Global Imager) sensors mounted on the ADEOS-2 satellite (Advanced Earth Observing Satellite-2) is proposed. The POLDER sensor provides three channels of unique directional polarization measurements, and the GLI sensor provides high-resolution images over a wide range of wavelengths from near-UV to thermal infrared. It is known that POLDER polarization data are effective for aerosol retrieval over land, and the ratio of reflectances at 0.40 and 0.38μm from GLI can be used to distinguish between nonabsorbing and absorbing aerosols. Our algorithm is tested by detecting the plume from Siberian biomass burning in May 2003. The retrieved aerosol properties are compared with model simulations and ground-based AERONET (Aerosol Robotic Network) data. The results show that our proposed algorithm provides improved data on the aerosol optical thickness.
• Estimation algorithm for aerosol properties from CAI on GOSAT

  I. Sano; S. Mukai; M. Mukai; B. Holben; I. Slutsker

  Proc. SPIE 7475 2009年 

  Green house gases observational satellite (GOSAT) was successfully launched on 23 January in 2009 by JAXA. The satellite carries two sensors, Fourier Transform Spectrometer (FTS) and Cloud Aerosol Imager (CAI). The CAI has four observing wavelengths as 0.38, 0.67, 0.87 and 1.6 mu m. It is shown here that this CAI/0.38 mu m is a unique observing band among usual sensors as MODIS and so on, and it is useful to distinguish the aerosol characteristics of absorbing (e. g., biomass burning) or non-absorbing (e. g., sulfate). In other word, this work proposed a space based retrieval algorithm for atmospheric aerosols including estimation of the optical constant for biomass burning particles. Our algorithm aims to apply the combination use of near UV data with GOAT/CAI, the violet data with Aqua/MODIS and near-IR polarization data with PARASOL/POLDER. In practice the algorithm has been partly examined by using ADEOS-2 / GLI data.
• 非球形粒子の偏光散乱数値シミュレーション

  岡田 靖彦; 佐野 到; 向井 苑生

  日本リモートセンシング学会誌 = Journal of the Remote Sensing Society of Japan 28 4 375 - 379 日本リモートセンシング学会 2008年09月
• 大気エアロゾルの光学特性と浮遊粒子状物質の相関解析

  向井 苑生; 向井 真木子; 佐野 到; 井口 信和

  エアロゾル研究 = Journal of aerosol research 23 2 114 - 119 日本エアロゾル学会 2008年06月 [査読有り]
   

  In order to analyze the urban atmospheric particles in Asia, we have undertaken simultaneous measurements of aerosols and suspended particulate matter (SPM) at a NASA/AERONET station at Kinki University Campus, Higashi-Osaka, since March in 2004. The relationship between concentration of suspended particulate matter (PM) and column aerosol optical thickness (AOT) is examined. It is found that a strong linear correlation exists between PM and AOT, and better correlation is obtained for the aerosols with the same origin, such as anthropogenic aerosols and dusts, rather than overall. The derived regression lines between PM<SUB>2.5</SUB> and AOT highlight the possibility that the PM<SUB>2.5</SUB> concentration can be estimated from the AOT, and vice versa. As a result, a distribution map of PM<SUB>2.5</SUB> has been obtained by using AOT values derived from Terra/MODIS data observed in April 2006 over East Asia.
• Acceleration of the iterative solver in the discrete dipole approximation: Application to the orientation variation of irregularly shaped particles

  Y. Okada; I. Mann; I. Sano; S. Mukai

  JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER 109 8 1461 - 1473 2008年05月 [査読有り]
   

  We have applied a method of reducing the number of iterations required to solve a system of linear equations in the discrete dipole approximation. This method obtains an initial guess of dipole polarization from those with similar particle characteristics (e.g., the size parameter and refractive index) calculated a priori. If the initial guess is closer to the solution, the number of iterations of the linear equation solution becomes smaller than that calculated with an arbitrary initial value. This method was applied to various particle orientations using spline interpolation of the initial guess of dipole polarization from orientations calculated a priori. We studied three types of particle model: an aggregate, a deformed sphere with moderate surface roughness, and a particle with a large number of edges. For the particle with a large number of edges, we propose a new model called the overlapping mixture of multiple tetrahedra (OMMT). The proposed method is most advantageous for particles with moderate surface roughness (e.g., a deformed sphere), for which the calculation time was reduced to 20-40% of the original calculation time. For OMMT and an aggregate, the computation time was reduced to 30-60% and 40-90%, respectively. The differences in the scattering coefficient, absorption coefficient, intensity and polarization introduced by our method were less than 0.008%, 0.03%, 0.1%, and 0.08%, respectively. If the light scattering properties vary slowly with the orientation variation, interpolation of the results is more efficient than the proposed method and produces only a small difference in the results. However, the interpolation of the results fails for particles such as BCCA64, for which our proposed method produces more accurate results. (C) 2008 Elsevier Ltd. All rights reserved.
• GOSAT衛星搭載イメージャーCAIを利用したエアロゾルと雲情報の抽出に関する研究

  中島 映至; 中島 孝; 日暮 明子; 佐野 到; 高村 民雄; 石田 春磨; シュトゲンズ ニック

  日本リモートセンシング学会誌 = Journal of the Remote Sensing Society of Japan 28 2 178 - 189 社団法人 日本リモートセンシング学会 2008年04月 [査読有り]
   

  The GOSAT satellite has been designed for retrieving the carbon dioxide amount in the atmosphere by a Fourier transform spectro-radiometer (TANSO-FTS). It is, however, known that FTS-observed radiances in the near-infrared spectral region are heavily contaminated by a solar radiation component scattered by atmospheric aerosols, which is known as "path radiance". In order to correct the path radiance, a multispectral visible-near infrared imager (TANSO-CAI) will be on board the GOSAT satellite to acquire the aerosol and cloud information that is indispensable for correcting the atmospheric path radiance to improve the carbon dioxide remote sensing by FTS. In this article, we study aerosol retrieval algorithms and cloud screening algorithms using the four channel radiances of CAI. We also present the methodology for vicarious calibration and validation for the CAI remote sensing, intercomparison of CAI-retrieved aerosol products with those from other satellite-borne sensors, and the data fusion strategy of satellite-measured and model-simulated aerosol properties.
• 2005・2006年に東大阪市で捕集された黄砂粒子の個別粒子分析

  中口 譲; 濱田 寛; 須山 祐樹; 佐野 到; 向井 苑生

  地球化学 41 4 155 - 163 日本地球化学会 2007年12月 [査読有り]
   

  The particle samples over Higashiosaka were collected by personal air sampler during asian-dust storms in April of 2005 and 2006. The size and elemental composition of individual perticles were investigated by scanning electron microprobe equipped energy-dispersive X-ray analyzer. From the results of individual particle analysis of Asian dust storm particles, Si-rich particles occupied 76.0% in 2.5-10.0μm diameter particles and 93.0% in <2.5μm diameter particles in April of 2005. In April 2006, Si-rich particles occupied 97.0% in 2.5-10.0μm diameter particles and 99.7% in <2.5μm diameter particles. Anthropogenic sulfur contaminated particles without sea salt were occupied by 2.2% in 2.5-10.0μm diameter particles and 3.6% in <2.5μm diameter particles in April 2005, and those were occupied by 0.4% in 2.5-10.0μm diameter particles and 2.9% in less than 2.5μm diameter particles in April 2006. From these results we confirmed that the degree of adsorption of anthropogenic sulfur oxides on to Asian dust storm particles during transport process from China to Japan was small in 2005 and 2006 over Higashiosaka.
• Grouping and adding method for calculating light scattering by large fluffy aggregates

  Y. Okada; T. Mukai; I. Mann; H. Nomura; T. Takeuchi; I. Sano; S. Mukai

  Journal of Quantitative Spectroscopy and Radiative Transfer 108 1 65 - 80 2007年11月 [査読有り]
   

  We present a method to derive the light scattering properties of very porous fractal aggregates composed of a large number of monomers where the size parameter of monomer is larger than unity. Our new method is based on the grouping of the aggregate: The aggregate is divided into groups, where each group is located along a line of the incident light, and the scattering properties of the group are calculated taking into account multiple scattering with monomers located inside the group, as well as those in a buffer region around the group. The scattering and absorption efficiencies are obtained by adding the resultant scattering properties for all the groups. We have shown that the method effectively works when the monomer scatters the incident lights predominantly in the forward direction, which is the case if the monomer size is large compared to the wavelength of the incident light. The errors in resulting scattering and absorption efficiencies for porous aggregates are investigated for various refractive indices and sizes of monomers. We found that the errors are larger for low absorbing materials and they can be reduced by expanding the buffer region. In the case of the buffer region for each group consisting of 1/8 of the total number of monomers, the results show errors less than 15% and 10% for absorption and scattering, respectively. It is also shown that the errors have a small standard deviation (i.e., 2%) for different directions of the incident light. © 2007 Elsevier Ltd. All rights reserved.
• Suspended particulate matter sampling at an urban AERONET site in Japan, part 1: clustering analysis of aerosols

  Sonoyo Mukai; Mitsuru Nishina; Itaru Sano; Makiko Mukai; Nobukazu Iguchi; Shoji Mizobuchia

  JOURNAL OF APPLIED REMOTE SENSING 1 2007年 [査読有り]
   

  The aerosol properties of urban atmospheric particles have been analyzed for radiometry data obtained using a multi-spectral photometer located at a NASA/AERONET station at Kinki University Campus, Higashi-Osaka, Japan, since 2002. The suspended particulate matter has been simultaneously measured at the same AERONET site since 2004. Our measurements and a clustering analysis reveal the aerosol types over the industrial city of Higashi-Osaka. It is shown that aerosols at Higashi-Osaka can be classified into three categories: (1) ordinary, which represents the background clear atmosphere of Higashi-Osaka, (2) anthropogenic aerosol events, and (2) dust episodes called Kosa, when large amounts of soil dust are transported to Higashi-Osaka from the Chinese mainland on westerly winds, especially in spring. We also found that the linear correlation exists between column aerosol optical thickness and PM2.5 concentration, and the correlation is better within each aerosol cluster than overall.
• A comparison of aerosol properties with air pollutants

  S. Mukai; I. Sano; A. Nishimori; M. Sato; Y. Okada; B. N. Holben

  Advances in Space Research 39 1 32 - 35 2007年 [査読有り]
   

  The aerosol properties obtained from radiometry with AERONET are compared with the particulate mass simultaneously measured with a new instrument (SPM-613D). AERONET sites have been set up at Shirahama since 2000 and at Osaka since 2002 to make measurements to improve the understanding background aerosols and characteristic features of the urban atmosphere over Japan, respectively. It is found that there was a strong correlation between the PM2.5 concentration and aerosol optical thickness. It indicates that aerosol characteristics can be estimated from SPM data, and vice versa. © 2006 COSPAR.
• 大気エアロゾルとSPMの同期測定が捉えた2006年春の黄砂

  向井 苑生; 佐野 到; 保本 正芳

  日本リモートセンシング学会誌 = Journal of the Remote Sensing Society of Japan 27 1 33 - 38 社団法人 日本リモートセンシング学会 2007年01月 [査読有り]
   

  To monitor urban atmospheric particles, we have undertaken simultaneous measurements of aerosols and suspended particulate matter (SPM) at Kinki University Campus, Higashi-Osaka, Japan, since 2004. The largest dust event recorded during our long-term observations was detected during the spring of 2006.We also examined the relationship between PM2.5 concentrations and aerosol properties obtained from radiometry using a multi-spectral photometer located at a NASA/AERONET station. We found a linear correlation between aerosol optical thickness and PM2.5 concentrations for both ordinary days and days with dust events.
• Aerosol properties and air pollutants over an urban area

  Sonoyo Mukai; Itaru Sano; Mutsumi Satoh; Brent N. Holben

  ATMOSPHERIC RESEARCH 82 3-4 643 - 651 2006年12月 [査読有り]
   

  For a better understanding of urban aerosols, sun/sky photometry has been undertaken at the Kinki University campus in Higashi-Osaka as a NASA/AERONET station since 2002. A new instrument, the SPM-613D (Kimoto Electric), has been taking measurements at the same site since March 15, 2004. The relationship between aerosol properties obtained from radiometry with AERONET and the SPM measurements is examined. It is found that there is a linear correlation between SPM concentrations and aerosol properties, which indicates that aerosol characteristics can be estimated from SPM data, and vice versa. It is also shown that the air quality of the Higashi-Osaka site is poor due to not only the anthropogenic particles by local emissions, such as diesel vehicles and chemical industries, but also due to the dust particles coming from continental desert areas by large scale climatic conditions. (c) 2006 Elsevier B.V. All rights reserved.
• Aerosol properties over Japan determined by sun/sky photometry

  Sonoyo Mukai; Itaru Sano; Brent N. Holben

  Water, Air, and Soil Pollution: Focus 5 3-6 133 - 143 2005年01月 [査読有り]
   

  The field-experiment campaigns of the Asian Atmospheric Particulate Environment Change Studies (APEX-E1 in December 2000, -E2 in spring 2001, and -E3 in spring 2003) aimed at understanding Asian aerosols. Our sun/sky photometric measurements of atmospheric light have joined these campaigns by using multispectral photometers (CE-318-1 and -2, Cimel Electronique and POM-100P, Prede) at Noto, Shirahama, and Fukue-jima, Japan. This paper focuses on aerosol retrieval during the APEX-E3 campaign. Aerosol optical thickness, Ångström exponent, single-scattering albedo and the refractive index derived from these ground-based measurements can be classified into three categories of aerosols: (1) an oceanic type of typical background aerosols over Japan, (2) an anthropogenic type, and (3) a soil-dust type. The data from APEX experiments demonstrate that aerosols over Japan exhibit complicated spatial and temporal features involving mixtures of compounds. © Springer Science + Business Media, Inc. 2005.
• Aerosol properties over Japan during APEX experiments in spring of 2001 and 2003

  I. Sano; S. Mukai; B.N. Holben; Y. Okada; M. Yasumoto

  OPTICA PURA Y APLICADA 37 3 3447 - 3451 2005年01月 [査読有り]
  
• Environmental snapshots from ACE-Asia

  Ralph Kahn; Jim Anderson; Theodore L. Anderson; Tim Bates; Fred Brechtel; Christian M. Carrico; Antony Clarke; Sarah J. Doherty; Ellsworth Dutton; Richard Flagan; Robert Frouin; Hajime Fukushima; Brent Holben; Steve Howell; Barry Huebert; Anne Jefferson; Haflidi Jonsson; Olga Kalashnikova; Jiyoung Kim; Sang-Woo Kim; Pinar Kus; Wen-Hao Li; John M. Livingston; Cameron McNaughton; John Merrill; Sonoyo Mukai; Toshiyuki Murayama; Teruyuki Nakajima; Patricia Quinn; Jens Redemann; Mark Rood; Phil Russell; Itaru Sano; Beat Schmid; John Seinfeld; Nobuo Sugimoto; Jian Wang; Ellsworth J. Welton; Jae-Gwang Won; Soon-Chang Yoon

  Journal of Geophysical Research D: Atmospheres 109 19 D19 - S14 2004年10月 [査読有り]
   

  On five occasions spanning the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia) field campaign in spring 2001, the Multiangle Imaging Spectroradiometer spaceborne instrument took data coincident with high-quality observations by instruments on two or more surface and airborne platforms. The cases capture a range of clean, polluted, and dusty aerosol conditions. With a three-stage optical modeling process, we synthesize the data from over 40 field instruments into layer-by-layer environmental snapshots that summarize what we know about the atmospheric and surface states at key locations during each event. We compare related measurements and discuss the implications of apparent discrepancies, at a level of detail appropriate for satellite retrieval algorithm and aerosol transport model validation. Aerosols within a few kilometers of the surface were composed primarily of pollution and Asian dust mixtures, as expected. Medium- and coarse-mode particle size distributions varied little among the events studied however, column aerosol optical depth changed by more than a factor of 4, and the near-surface proportion of dust ranged between 25% and 50%. The amount of absorbing material in the submicron fraction was highest when near-surface winds crossed Beijing and the Korean Peninsula and was considerably lower for all other cases. Having simultaneous single-scattering albedo measurements at more than one wavelength would significantly reduce the remaining optical model uncertainties. The consistency of component particle microphysical properties among the five events, even in this relatively complex aerosol environment, suggests that global, satellite-derived maps of aerosol optical depth and aerosol mixture (air-mass-type) extent, combined with targeted in situ component microphysical property measurements, can provide a detailed global picture of aerosol behavior. Copyright 2004 by the American Geophysical Union.
• Aerosol properties from MIRAI research cruise in the tropical Pacific Ocean

  Y Okada; S Mukai; Sano, I; K Kozai; H Ishida

  ADVANCES IN SPACE RESEARCH 33 7 1195 - 1199 2004年 [査読有り]
   

  Aerosol parameters are observed with a photopolarimeter (PSR-1000 device) and by SeaWiFS sensor during two research cruises conducted by R/V MIRAI in the equatorial Pacific regions. Observation of aerosol particles has shown the background characteristics of aerosol particles. The aerosol optical thickness calculated from PSR-1000 data coincide well with those from SeaWiFS data at 0.865 mum and shows difference at 0.443 mum. It is also shown that the data with low aerosol optical thickness has an ambiguity in the calculation of the Angstrom exponent for various sets of wavelengths. The refractive index of aerosol particles is retrieved by combining data from direct solar measurements and those from polarization measurements of scattered sun-light. (C) 2003 COSPAR. Published by Elsevier Ltd. All rights reserved.
• Optical thickness and Angstrom exponent of aerosols over the land and ocean from space-borne polarimetric data

  Sano, I

  ADVANCES IN SPACE RESEARCH 34 4 833 - 837 2004年 [査読有り]
   

  This work describes a procedure to retrieve aerosol characteristics, e.g., optical thickness of aerosols at a wavelength of 0.55 mum and its Angstrom exponent, all over the world from Polarization and Directionality of Earth Surface (POLDER) data acquired on board the Advanced Earth Observing Satellite-1 (ADEOS-1). The two parameters indicate the basic information, amount and particle size, respectively. The derived global map, presented in a color plate consisted of optical thickness and Angstrom exponent of aerosols is useful to monitor aerosol distribution. It is found that aerosol loading in central Africa and Asia is always high throughout the year. The results retrieved from ADEOS/POLDER are validated with NASA/AERONET (Aerosol Robotic Network) data. (C) 2004 COSPAR. Published by Elsevier Ltd. All rights reserved.
• A study of the direct and indirect effects of aerosols using global satellite data sets of aerosol and cloud parameters

  Miho Sekiguchi; Teruyuki Nakajima; Kentaroh Suzuki; Kazuaki Kawamoto; Akiko Higurashi; Daniel Rosenfeld; Itaru Sano; Sanoyo Mukai

  Journal of Geophysical Research 108 D22 2003年11月 [査読有り]
   

  The present study investigated the correlations between aerosol and cloud parameters derived from satellite remote sensing for evaluating the radiative forcing of the aerosol indirect effect. The global statistics showed that the effective particle radius and the optical thickness of low clouds correlate well with the column number concentration of the aerosol particles, indicating an aerosol indirect effect. A correlation of the cloud fraction with the aerosol number was also seen, whereas we could not find a significant correlation of the cloud-top temperature with the column aerosol number. Furthermore, the regional statistics presented that positive correlations between the cloud optical thickness and cloud fraction with the aerosol column number concentration exist in most regions consistent with the global mean statistics. However, the effective cloud particle radius showed a tendency similar to the global correlation only around the seashore regions. Using these correlations and assuming that the aerosol column number concentration has increased by 30% from the preindustrial era, the total radiative forcing of the aerosol indirect effect was evaluated to be about -0.6 to -1.2 W m-2. The radiative forcing of the aerosol direct effect from the satellite-retrieved parameters was also evaluated as -0.4 W m-2 over the ocean. The cloud-top temperature was found to be insensitive to the change in the aerosol number, although there was a distinct negative correlation between the aerosol number and cloud temperature at which the cloud particle grows to a radius of 14 μm. This particular dependency of the cloud temperature suggests that aerosols acts on clouds so as to change cloud particle size near the cloud top, optical thickness, and fraction but to keep their cloud-top temperature without causing a significant longwave radiative forcing. Copyright 2003 by the American Geophysical Union.
• Sea WiFSデータによる雲域同定手法の改良

  岡田靖彦; 向井 苑生; 佐野 到

  Geophy. Res. Lett. 30 4 1193 - 1197 A.G.U. 2003年02月 [査読有り]
   

  水色センサSea WiFSデータによる雲域決定アルゴリズムの精度向上法の考案。（英文）
• Interrelation of aerosols, water vapor and clouds on a global scale

  S Mukai; Sano, I; M Yasumoto

  ADVANCES IN SPACE RESEARCH 32 11 2181 - 2190 2003年 [査読有り]
   

  Each retrieval algorithm for atmospheric aerosols, clouds and water vapor from ADEOS/POLDER data is described. A POLDER sensor, mounted on the Earth observation satellite ADEOS in 1996, is a unique sensor which can gather multi-directional (up to 14) polarization measurements of one target. Atmospheric aerosol properties as optical thickness and Angstrom exponent are derived from the POLDER polarization data at wavelengths of 0.670 and 0.865 mum. The polarization data at 0.865 mum is also available for cloud retrieval. Two channels in the near infrared wavelengths are used to estimate the total column water vapor content. The first channel is in the water vapor absorption band of 0.910 mum and the second is in the gas absorption-free band of 0.865 mum. In practice, a ratio of each reflectance for these two channels is used in this study. Then the obtained global maps of aerosol properties, cloud microphysics and water vapor content are compared with one another. It is shown that column number density of aerosols has a negative correlation with the effective radius of cloud particles and proportionally correlates with the optical thickness and the column number density of cloud particles. These results confirm the indirect effect of aerosols, namely aerosols play sufficient role as cloud condensation nuclei (CCN). (C) 2003 COSPAR. Published by Elsevier Ltd. All rights reserved.
• Calibration and validation of retrieved aerosol properties based on AERONET and SKYNET

  Sano, I; S Mukai; M Yamano; T Takamura; T Nakajima; B Holben

  ADVANCES IN SPACE RESEARCH 32 11 2159 - 2164 2003年 [査読有り]
   

  This study compares the function of AERONET and SKYNET, which are well known components of the ground-based aerosol-monitoring network. AERONET uses the Cimel CE-318-1 and -2 sun/sky photometer system, and SKYNET adopts Prede POM-01, -02, and -100P sun/sky photometers (aka skyradiometer). These are available for direct- or diffuse-solar radiation measurements in order to calculate aerosol optical thickness or other aerosol properties such as size distribution, respectively. The CE-318-2 (AERONET) and the POM-100P (SKYNET) instruments have recently been installed at Kinki University in Osaka, Japan, for the retrieval of aerosol data. These have been calibrated at NASA/GSFC and at the Mauna Loa Observatory, respectively, based on the Langley plot method. The difference in the aerosol optical thickness derived from simultaneous measurements using these two types of radiometer was less than 0.008 (<4% relative error). Simultaneous observation with AERONET and SKYNET in Osaka allows us to combine AERONET and SKYNET on a global scale. It is of interest that the aerosols over Osaka exhibit quite specific characteristics due to heavy industrial aerosol loading throughout the year and frequent yellow sand events in the spring. (C) 2003 COSPAR. Published by Elsevier Ltd. All rights reserved.
• Optical properties of aerosols during APEX and ACE-Asia experiments

  Itaru Sano; Sonoyo Mukai; Yasuhiko Okada; Brent N. Holben; Sachio Ohta; Tamio Takamura

  Journal of Geophysical Research 108 D23 8649  2003年 [査読有り]
  
• Modeling study of long-range transport of Asian dust and anthropogenic aerosols from East Asia

  T Takemura; Uno, I; T Nakajima; A Higurashi; Sano, I

  GEOPHYSICAL RESEARCH LETTERS 29 24 11.1 - 11.4 2002年12月 [査読有り]
   

  [1] A three-dimensional aerosol transport-radiation model, SPRINTARS, successfully simulates the long-range transport of the large-scale Asian dust storms from East Asia to North America which crossed the North Pacific Ocean during the springtime of 2001 and 2002. It is found from the calculated dust optical thickness that 10 to 20% of the Asian dust around Japan reached North America. The simulation also reveals the importance of the contribution of anthropogenic aerosols, which are carbonaceous and sulfate aerosols emitted from the industrialized areas in East Asia, to air turbidity during the dust storms. The contribution of the anthropogenic aerosol to the total optical thickness is simulated to be of a comparable order to that of the Asian dust, which is consistent with the observed values of the particle size index from the satellite and ground-based sun/sky photometry.
• A new algorithm to retrieve aerosol over the gulf of cambay in India

  Yasuhiko Okada; Sonoyo Mukai; Itaru Sano

  J. Indi. Rem. Sen 30 1-2 81 - 86 Indian Remote Sensing Society 2002年03月 [査読有り]
   

  土壌流出沿岸域（インド・カンベイ湾）におけるエアロゾル特性の導出法と画像表示。（英文）
• Combined use of OCTS and POLDER for cloud retrieval

  M Yasumoto; Sano, I; S Mukai

  Adv. Space Res. 29 1 39 - 44 Elsevier 2002年 [査読有り]
   

  ADEOS衛星搭載POLDER/OCTSセンサデータの複合利用を用いた雲粒子特性の導出について（英語）
• Photopolarimetric observations of atmospheric aerosols from space and/or sea surface

  Sano, I; M Lynch; K Ogasa; S Mukai

  ADVANCES IN SPACE RESEARCH 29 11 1867 - 1872 2002年 [査読有り]
   

  This work presents spatial and temporal change of optical properties of aerosols over Japan and Western Australia. The measurements by a portable multi-spectral polarimeter (PSR-1000) from 1997 to 2000 provide the optical thickness of aerosols and the (A) over circle ngstrom exponent. For comparison, the same aerosol parameters are derived from the satellite data, e.g. ADEOS / POLDER and/or SeaWiFS data. It is shown that the obtained results from the space-based data are validated with the results from the ground measurements on a local scale, and the retrieved aerosol characteristics exhibit each intrinsic feature for each region. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.
• 西部太平洋赤道上空エアロゾルの光学的厚さ；みらい観測と光散乱シミュレーションから

  向井 苑生; 岡田靖彦; 佐野 到; 香西克俊; 石

  海と空 78 3 95 - 100 海洋気象学会 2002年 [査読有り]
   

  JAMSTECみらい研究航海で得られた西部太平洋赤道上空エアロゾルについて。
• 大気エアロゾルの洋上偏光観測

  向井 苑生; 佐野 到; 岡田 靖彦; 小笠 一史; 北島 武志; 香西 克俊; 石田 廣史

  海と空 77 3 127 - 133 海洋気象学会 2001年12月 [査読有り]
  
• 偏光データを用いた大気エアロゾルリモートセンシング

  佐野 到; 向井 苑生

  エアロゾル研究 = Journal of aerosol research 16 2 105 - 110 日本エアロゾル学会 2001年06月 [査読有り]
  
• Atmospheric correction for the ASTER visible data on Terra satellite

  T. Takashima; K. Masuda; I. Sano; S. Mukai

  Advances in Space Research 28 1 177 - 182 2001年01月 [査読有り]
  
• Cross-calibration of ADEOS/OCTS and polder and the influence on aerosol retrieval

  S Mukai; Y Okada; Sano, I

  Adv. Space Res. 28 1 41 - 48 2001年 [査読有り]
   

  ASDEOS 衛星搭載センサー OCTS と POLDER の相互校正とその差異が与える大気エアロゾル導出への影響を考察。 （英文）
• エアロゾル特性導出における偏光情報の役割

  佐野 到; 向井 苑生

  日本リモートセンシング学会誌 = Journal of the Remote Sensing Society of Japan 20 5 503 - 510 2000年12月 [査読有り]
  
• ADEOS/OCTSとPOLDERデータの複合利用1.放射輝度測定誤差がエアロゾル・リトリーバルに与える影響の評価

  向井 苑生; 岡田 靖彦; 佐野 到

  日本リモートセンシング学会誌 = Journal of the Remote Sensing Society of Japan 20 4 362 - 371 日本リモ-トセンシング学会 2000年12月 [査読有り]
  
• Inverse problems in the atmosphere-ocean system: estimation of aerosol characteristics and phytoplankton distribution

  S Mukai; Sano, I; Y Okada

  APPLIED MATHEMATICS AND COMPUTATION 116 1-2 93 - 101 2000年11月 [査読有り]
   

  This work attempts to provide a better atmospheric correction For space-based data obtained with second-generation ocean color sensors, e.g., ADEOS (Advanced Earth Observing Satellite)/OCTS (Ocean Color and Temperature Scanner) and POLDER (Polarization and Directionality of Earth Reflectance). Before atmospheric correction, it is necessary to estimate the optical properties of atmospheric aerosols, and then phytoplankton pigment concentration near the sea surface is obtained after atmospheric correction. In other words, this paper deals with the inverse problem of determining such physical quantities as aerosols and phytoplankton using indirect space-based measurements. Our algorithm is based on an estimation of unknown parameters in the scattering systems observed remotely by satellite. (C) 2000 Elsevier Science Inc. All rights reserved.
• Algorithm description of system flow for global aerosol distribution

  Sano, I; S Mukai

  APPLIED MATHEMATICS AND COMPUTATION 116 1-2 79 - 91 2000年11月 [査読有り]
   

  This paper describes a processing flow to extract aerosol characteristics on a global scale from polarization and directionality of Earth reflectance (POLDER) level 1 data. POLDER provides radiance and polarization in the visible and near-infrared regions. Our procedure is composed of two phases; one is a data reduction process from the POLDER level 1 to the global scale, and the other is the aerosol retrieval process. The retrieval algorithm is achieved in practice using a look-up table which is compiled based on multiple scattering simulations in an atmosphere-sea surface system. Monthly global distribution maps showing the Angstrom exponent and the optical thickness of aerosols were obtained in November 1996 and in January and April 1997. From these aerosol maps, it can be seen that: (1) the aerosol distribution derived from POLDER radiance and polarization data coincides with the radiance data obtained independently from OCTS, (2) atmospheric aerosols exhibit certain intrinsic feature on a global and on a seasonal scale. (C) 2000 Elsevier Science Inc. All rights reserved.
• POLDER多方向データから導出したエアロゾル特性の全球分布

  向井 苑生; 佐野 到

  日本リモートセンシング学会誌 = Journal of the Remote Sensing Society of Japan 20 3 309 - 317 日本リモ-トセンシング学会 2000年09月 [査読有り]
  
• Evaluation of retrieval algorithms for atmospheric aerosols with multi-directional observations by ADEOS/POLDER

  Sano, I; S Mukai

  ADVANCES IN SPACE RESEARCH 25 5 963 - 966 2000年 [査読有り]
   

  The first space-based polarization measurements were undertaken by ADEOO/PPODER. The POLDER has supplied the observed data not only in the multi-wavelength bands but also at the multi-viewing angles. These directional measurements include significant information of atmospheric aerosols. This work is a feasibility study of multi-directional data for the retrieval of aerosols characteristics. The basic algorithms for aerosol retrieval is based on light scattering simulations of polarization field, where the heterogeneous aerosol model according to Maxwell-Garnett mixing rule is considered. It is shown that polarization data observed at multi-angles is a powerful tool to retrieve aerosol characteristics, and that the obtained aerosol distribution indicates the regional trend of atmospheric condition over the North Pacific Ocean near Japan. (C) 2000 COSPAR. Published by Elsevier Science Ltd.
• Atmospheric correction for ocean color data given by ADEOS/OCTS and POLDER

  S Mukai; Sano, I; Y Okada

  ADVANCES IN SPACE RESEARCH 25 5 1025 - 1028 2000年 [査読有り]
   

  A better atmospheric correction for space-based data given by the second generation of ocean color sensors, e.g. ADEOS/OCTS and POLDER, is the main aim of this work. The new sensors possess high radiometric sensitivity and multi-channels in the visible and near-infrared wavelengths. We consider a heterogeneous aerosol model following the Maxwell-Garnett mixing rule with small water-soluble inclusions in an oceanic matrix to interpret both the OCTS and POLDER data in the near infrared wavelength. Then we apply an atmospheric correction process in an atmosphere-ocean model involving the retrieved aerosol models. Finally our procedure provides the phytoplankton pigment concentration near the sea surface over the Pacific Ocean near Japan on April 26, 1997. (C) 2000 COSPAR. Published by Elsevier Science Ltd.
• 多波長偏光放射計の校正

  保本 正芳; 向井 苑生; 中村 良介; 佐野 到

  遊・星・人 : 日本惑星科学会誌 8 2 95 - 100 日本惑星科学会 1999年06月 [査読有り]
  
• Algorithms for aerosol retrieval based on scattering calculations

  S Mukai; Sano, I

  COMPUTERS & MATHEMATICS WITH APPLICATIONS 37 11-12 133 - 139 1999年06月 [査読有り]
   

  This paper focuses on how to determine an accurate aerosol model based on simulations of light scattering. Our algorithms come from an idea that aerosol characteristics can be estimated in terms of the scattering behavior. The correlation coefficients between measurements of atmospheric aerosols and the simulated values for model particles are used to retrieve aerosol characteristics. The space-borne data by Nimbus7-CZCS at a wavelength 0.67 mu m and the photopolarimetric measurements of aerosols with a portable photopolarimeter (FPR2000) at wavelengths of 0.559, 0.662, and 0.811 mu m are examined in this work. It is shown here that aerosol models are precisely determined by combining use of polarization measurements and radiance data. (C) 1999 Elsevier Science Ltd. All rights reserved.
• Detection of atmospheric aerosol over Lunar lake, Nevada, using ground based skylight polarization measurements

  T Takashima; K Masuda; S Mukai; I Sano

  Advances in Space Research 23 8 1525 - 1528 1999年01月 [査読有り]
  
• Retrieval algorithm for atmospheric aerosols based on multi-angle viewing of ADEOS/POLDER

  S Mukai; Sano, I

  EARTH PLANETS AND SPACE 51 11 1247 - 1254 1999年 [査読有り]
   

  POLDER-sensor onboard the satellite ADEOS has observed the reflected light from Earth surface-atmosphere system at multi-viewing angles. These directional measurements include significant information of scattering particles. The POLDER possesses high radiometric sensitivity and multi-channels in the visible and near infrared wavelengths, and measures polarization as well as radiance. This work intends to show that its multi-spectral and multi-directional measurements are useful to retrieve aerosol characteristics. The basic algorithm for aerosol retrieval is based on light scattering simulations of polarization field, where the heterogeneous aerosol model according to Maxwell-Garnett mixing rule is considered. Monthly global distribution maps showing the Angstrom exponent and the optical thickness of aerosols were obtained. From these aerosol maps, it can be seen that the aerosol distribution derived from POLDER radiance and polarization data coincides with that from the radiance data obtained independently from OCTS, and atmospheric aerosols exhibit certain intrinsic feature on a global and on a seasonal scale.
• Similarity and diversity of OCTS and polder from an ocean color analysis point of view

  S Mukai; Sano, I

  ADVANCES IN SPACE RESEARCH 23 8 1397 - 1400 1999年 [査読有り]
   

  Comparison and combination of two ocean color sensors, ADEOS/OCTS and POLDER, are treated in this work. These new sensors possess high radiometric sensitivity and multi-spectral bands in the visible and near-infrared wavelengths. It is of interest to mention that the POLDER provides the data at the multiviewing angles. These directional measurements include significant information of atmospheric aerosols. In addition POLDER measures polarization as well as radiance. It is shown here that aerosol retrieval can be efficiently pursued by a combination of radiance and polarization. As a result, it is found that the retrieved distribution of aerosol optical thickness and the phytoplankton pigment concentration near the sea surface obtained from the OCTS data coincide with those from the POLDER data within the tolerances required at the present time. (C) 1999 COSPAR. Published by Elsevier Science Ltd.
• ADEOS/ILAS aerosol retrieval algorithm with 5 channels

  H. Okamoto; Y. Sasano; S. Mukai; I. Sano; H. Ishihara; T. Matsumoto; L. Thomason; M. Pitts

  Advances in Space Research 21 3 443 - 446 1998年 [査読有り]
   

  The information content of aerosol properties is discussed for a set of extinction coefficient measurements of the ILAS (Improved Limb Atmospheric Spectrometer) instrument. ILAS was launched on the ADEOS (Advanced Earth Observing Satellite) spacecraft in 1996 and has a wide spectral coverage in the infrared region (between 6.21 and 11.77 μm). From these extinction measurements, ILAS has a capability to provide the vertical profiles of gaseous species, which are important for studies of the ozone hole phenomena, as well as the stratospheric aerosol compositions. In this paper, we describe an algorithm to infer the chemical composition of aerosols, i.e., types of PSCs (polar stratospheric clouds), the size distributions, total volume and total surface areas of aerosols by using five window channels, i.e. one at visible waveleugth(0.78μm) and four (7.12. 8.27, 10.60. 11.76μm) at infrared wavelengths. Our algorithm mainly consists of two parts. The first part is to determine the chemical composition of PSCs and eulfate aerosols. The second one is to derive the mean size, volume and surface area. The main purposes of this paper are to provide the extinction spectrum over the whole infrared channels in order to estimate the reliable amounts of trace gases and also to estimate the information of aerosol surface distribution for heterogeneous chemical reaction studies on PSCs. © 1998 COSPAR. Published by Elsevier Science Ltd.
• Removal of scattered light in the Earth atmosphere

  S Mukai; Sano, I; A Toigo

  EARTH PLANETS AND SPACE 50 6-7 595 - 601 1998年 [査読有り]
   

  Atmospheric correction algorithm, which means a procedure to remove scattered light in an atmosphere from the spaced-based data, are shown for ocean color data given by the satellite ADEOS. In order to achieve better atmospheric correction, this paper proposes two subjects; one is how to determine aerosol characteristics by referring to both of radiance and polarization, and the other is introduction of atmospheric correction coefficients. At first it is shown that a heterogeneous grain model according to Maxwell-Garnett mixing rule as small water-soluble (WS) inclusions in an oceanic (OC) matrix is available to interpret ADEOS/OCTS and POLDER data observed over the Arabian Sea. Our algorithm is based on an idea that aerosol characteristics can be estimated in terms of scattering behavior in the polarization field. Then atmospheric correction, which is based on radiative transfer process in an atmosphere-ocean model involving the retrieved aerosol model, is applied to ocean color data given by ADEOS/OCTS. Finally our atmospheric correction provides an expected chlorophyll map near the sea surface. It is of interest to mention that retrieval of atmospheric aerosols is improved by combination use of radiance and polarization, moreover atmospheric correction process is progressed by using the correction coefficients.
• Polarimetric properties of aerosol particles

  Sano, I; S Mukai

  EARTH PLANETS AND SPACE 50 6-7 513 - 519 1998年 [査読有り]
   

  Retrieval algorithms for scattering particles are shown based on photopolarimeric measurements of sky light over the ocean and multiple scattering simulations of the polarization field. Polarized components of the atmospheric constituents have been measured by a photopolarimeter (named PSR 1000) with spectral bands set up to correspond to the ADEOS/POLDER. The POLDER is the first sensor on board the satellite to be designed to observe polarization. It is shown that heterogeneous grains are better than homogeneous models to explain polarimetric properties of atmospheric aerosols, and a Maxwell-Garnett mixing rule for small water-soluble (WS) inclusions in an oceanic (OC) matrix is available to interpret the polarization measurements of atmospheric aerosols over the Seto Inland Sea. We also found during our observations that the value of refractive index of the aerosol, i.e., its chemical composition, varies with time and place rather than particle size.
• POLDERデータを用いたエアロゾル特性の導出 2. OCTSデータとの複合利用

  向井 苑生; 佐野 到; 高島 勉; 増田 一彦

  日本リモートセンシング学会誌 = Journal of the Remote Sensing Society of Japan 17 5 439 - 444 日本リモ-トセンシング学会 1997年12月 [査読有り]
  
• POLDERデータを用いたエアロゾル特性の導出 1. データの切り出しからフレーム画像表示まで

  佐野 到; 向井 苑生

  日本リモートセンシング学会誌 = Journal of the Remote Sensing Society of Japan 17 5 545 - 550 日本リモ-トセンシング学会 1997年12月 [査読有り]
  
• Validation of atmospheric correction algorithms based on multi-sensor data

  S. Mukai; I. Sano; T. Takashima; K. Masuda

  Advances in Space Research 19 9 1371 - 1374 1997年01月 [査読有り]
  
• Multispectral polarization measurements of atmospheric aerosols

  Sano, I; S Mukai; T Takashima

  ADVANCES IN SPACE RESEARCH 19 9 1379 - 1382 1997年 [査読有り]
   

  This work presents the polarization measurements of atmospheric aerosols and how to estimate optical properties of aerosols based on simulations of polarization field. Polarization degrees of aerosols were measured with our new portable polarimeter, whose spectral coverage is [0.443, 0.865] mu m. The observations were undertaken at Meteorological Research Institute (Tsukuba) and Kinki University (Osaka) in 1996. We found the sequential change of aerosol characteristics according to the variation of polarization data on temporal scale. (C) 1997 COSPAR. Published by Elsevier Science Ltd.
• Investigation of atmospheric aerosols based on polarization measurements and scattering simulations

  S Mukai; Sano, I; T Takashima

  OPTICAL REVIEW 3 6B 487 - 491 1996年11月 [査読有り]
   

  For an ongoing project involving ocean color and temperature scanner and polarization and directionary of the earth's reflectance onboard the advanced earth observing satellite, the radiance and degree of polarization of atmospheric aerosols were measured with a portable photopolarimeter (FPR2000) at wavelengths of 0.559, 0.760 and 0.811 mu m. The observations were undertaken over the ocean around Shikoku Island of Japan on clear days with few clouds in July, 1995. The measurements were compared with simulations of polarization fields. This work also describes retrieval algorithms for aerosols. It is shown that: (I) the radiance decreases with wavelength, (2) oceanic type aerosols are available to evaluate the degree of polarization over the Pacific Ocean, and (3) polarization data in the Seto Inland Sea are explained by a water-soluble aerosol model.
• Optical I roperties of stratospheric aerosols

  S. Mukai; I. Sano; Y. Sasano; M. Suzuki; T. Yokota

  Advances in Space Research 17 1 67 - 70 1996年01月 [査読有り]
  
• Retrieval algorithms for photopolarimetric properties of aerosols

  I. Sano; S. Mukai; T. Takashima; Y. Yamaguchi

  Advances in Space Research 17 1 63 - 66 1996年01月 [査読有り]
   

  Retrieval algorithms for atmospheric aerosols are proposed in this paper using photopolarimetric measurements based on simulations of polarization fields. The radiance and degree of polarization of atmospheric aerosols were measured with a portable photopolarimeter (FPR2000) at wavelengths of 0.559, 0.662 and 0.811 μm which correspond to the wavelengths of the Optical Sensor (OPS) aboard the Japanese Earth Resources Satellite (JERS), in order to confirm the accuracy of the JERS observations. Our algorithms are based on an idea that aerosol characteristics can be estimated in terms of the scattering behavior. It is shown here that polarization is a powerful tool in determining aerosol characteristics and their variation on spatial and temporal scales.
• THE ROLE OF AEROSOLS IN LIGHT-SCATTERING IN THE ATMOSPHERE

  SANO, I; S MUKAI

  OPTICAL REVIEW 2 4 298 - 303 1995年08月 [査読有り]
   

  This paper addresses the important role of how aerosols play in light scattering in the earth's atmosphere and how their characteristics can be retrieved. It is shown here, by referring to typical aerosol types, that more than a half of the atmospheric light is scattered by aerosols, and the aerosol optical properties can be estimated in terms of the scattering behavior. It is also confirmed that aerosol retrieval can be accurately determined by combining polarization and radiance data.
• Chlorophyll map from the ocean color sensors

  Sonoyo Mukai; Itaru Sano; Kazuya Takemata

  Advances in Space Research 14 3 191 - 194 1994年 [査読有り]
   

  The aim of this study is to get the information of oceanic features around Japanese islands from satellite data. We show first the relationship between ocean color, which represents phytoplankton pigment concentration, and sea surface temperature by using truth data compiled by JODC. Next the ocean color data by Nimbus-7 CZCS is treated, and then chlorophyll map and thermal pattern are derived. These satellite derived maps are classified with a unsupervised clustering technique. As a result, it is found that our results processed from the satellite data partially coincide with the truth data by ships in respect of the relationship between ocean color and temperature. © 1993.
• Retrieval algorithms for stratospheric aerosols based on ADEOS/ILAS measurements.

  Sonoyo Mukai; Itaru Sano; Yasuhiro Sasano; Makoto Suzuki; Tatsuya Yokota

  IEEE Trans. Geoscience and Remote Sensing 32 5 1124 - 1127 1994年 [査読有り]
  
• Atmospheric Correction for Ocean Color Remote Sensing: Optical Properties of Aerosols Derived from CZCS Imagery

  Sonoyo Mukai; Itaru Sano; Kazuhiko Masuda; Tsutomu Takashima

  IEEE Transactions on Geoscience and Remote Sensing 30 4 818 - 824 1992年 [査読有り]
   

  A procedure to pursue an accurate atmospheric correction for ocean color remote sensing is described. It is shown that an appropriate aerosol model is the key factor to pursue our atmospheric correction including multiple scattering light in the atmosphere-ocean system. Here an algorithm to estimate the aerosol models suitable for the Nimbus-7 CZCS image of interest is proposed. As a result, phytoplankton pigment concentration near the sea surface is derived through our atmospheric correction and biooptical algorithms. It is emphasized that our treatment provides the improved pigment map of the sea surface near Japan. © 1992 IEEE

書籍

• Atmospheric Aerosols: Life Cycles and Effects on Air Quality and Climate

  Sandro Fuzzi; Stefania Gilardoni; Alexander A. Kokhanovsky; Walter Di Nicolantonio; Sonoyo Mukai; Itaru Sano; Makiko Nakata; Claudio Tomasi; Christian Lanconelli (担当:分担執筆範囲:Chapter 9)Wiley 2017年01月 ISBN: 9783527336456 704 Chapter 9 (共著)

MISC

• GCOM-C/SGLIを用いた森林火災起源エアロゾルの特徴把握

  中田真木子; 佐野到; 向井苑生 日本気象学会大会講演予稿集(CD-ROM) (122) 2022年
• しきさい衛星データの特長である偏光・多波長データを生かした大気粒子解析

  向井苑生; 日置壮一郎; 中田真木子; 佐野到 日本リモートセンシング学会学術講演会論文集(CD-ROM) 73rd 2022年
• GRASP : リモセン界のスーパーモデル—The best system for atmospheric remote sensing

  向井 苑生; 佐野 到; 中田 真木子; Oleg Dubovik NAIS journal 13 52 -56 2019年03月

受賞

• 平成14年 日本リモートセンシング学会論文賞
  

共同研究・競争的資金等の研究課題

• 東アジアを越境するバイオエアロゾル：日本本土への拡散・沈着とその生体影響の評価

  日本学術振興会：科学研究費助成事業

  研究期間 : 2021年04月 -2025年03月 

  代表者 : 牧 輝弥; 佐野 到; 黒崎 泰典; 石塚 正秀; 大西 一成; 能田 淳; 松木 篤; 定金 香里; 市瀬 孝道

   

  黄砂や煙霧とともに微生物群(バイオエアロゾル)が，アジア大陸から日本へ越境輸送され，日本各地へと拡散沈着するため，その環境・健康影響に学術的関心が集まる。申請者らは，東アジア(日中韓蒙)において，黄砂を捕集する高高度調査(気球, ヘリコプター, 山岳積雪を使用)を実施し，日本へと越境輸送された微生物の種組成とその健康影響が，日本海沿岸と太平洋沿岸で大別できる可能性を突き止めた。しかし，観測地点は日本海側に偏り，太平洋側への国内移送や沈着程度を講じる観測が不十分であった。本申請では，日本本土(日本海ー太平洋)の観測地を拡充し，「越境微生物の国内での拡散・沈着過程」を理解すると伴に，そ影響を評価する。 黄砂飛来時に日本海側（能登）と太平洋側（関西，関東）の上空500ー2500ｍにおいてヘリコプター観測を行い，高高度の大気粒子を捕集した。また，黄砂・煙霧発生が頻発する春から初夏(4月-6月)にかけて，金沢，鳥取，香川，東京，長野，大阪の観測地において，建物屋上(高さ10m)で長期的に観測した。大気試料のゲノムDNA（環境ゲノム）に含まれる細菌・カビの分類指標遺伝子（16SとITS）核酸塩基配列を解読した。遺伝子解析ソフト(Qiime2)で微生物群集構造を解析したところ，黄砂と煙霧によって細菌は越境しやすく，本国内において真菌と混合する傾向が見られた。感染症（非結核抗酸症）の原因微生物も検出され，潜在的に長距離拡散される可能性も見出した。また分離した真菌株からもカビ毒が検出された。これより，黄砂煙霧とともに国内を拡散する有害種(キーストーン種)の候補に目処が立ちつつある。 こうした研究成果は，環境系の有名学術誌に多数掲載され，書籍「大気微生物の世界」にまとめられた。また，一般からの注目も熱く，大気観測全般を纏めたガリレオXやNHKスペシャルなどの取材を受けた。
• エアロゾル輸送における山岳地形効果の解明

  日本学術振興会：科学研究費助成事業

  研究期間 : 2019年04月 -2023年03月 

  代表者 : 佐野 到; 向井 苑生; 中田 真木子

   

  本研究課題「エアロゾル輸送における山岳地形効果の解明」実施のため下記のプロジェクトを実施中である．特に2021年度の内容に関して報告を行う． ■日米共同観測「DRAGON J-ALPS」に基づく計測実験（2021年度）：米国NASAとの打合せで2021年3～5月の春季において再実験を行った．2020年度内に機器のメンテナンス，再設置，必要な機器の交換を済ませた．2021年度も引き続きコロナウイルスの影響を受けたが概ね機器が順調に稼働し，無事集中実験期間が終了できた．国立・国定公園内に設置した一部の機器は期限となる6月に撤去を行ったが，その他の大部分は10月～12月まで稼働を続けることができた．回収した機器は米国内にて2022年度6月頃には再校正が終了し，データが確定予定である． ■衛星計測：2021年度も引き続きGCOM-C衛星SGLIデータ，Himawari-8衛星AHIデータを用いて，特に黄砂イベントを中心に解析を行った． ■領域モデル：2020年度末に実施した集中観測の初期解析をSCALE-Chemによるモデルシミュレーションを用いて実施し米国AGUが発刊する国際オンライン論文誌（Natata et al., Effects of Mountains on Aerosols Determined by AERONET/DRAGON/J-ALPS Measurements and Regional Model Simulations, Earth and Space Science, doi:10.1029/2021EA001972）に掲載された．
• 大気微小（エアロゾル・PM）粒子の高精度推定：多波長並びに偏光情報の活用

  日本学術振興会：科学研究費助成事業

  研究期間 : 2015年04月 -2018年03月 

  代表者 : 向井 苑生; 佐野 到; 保本 正芳; 中田 真木子

   

  多波長・偏光衛星データを基盤情報とした大気エアロゾル特性導出手法を考案し，実効システムを作成した．3年間の成果・達成度・今後の発展計画をまとめる： ①効率的なエアロゾルモデルの提案．②偏光・非偏光両放射場に柔軟に対応可能な放射伝達システム作成．③近紫外並びに紫バンドデータ比で定義する吸収性エアロゾル識別指標(AAI)を提案．④大気汚染やPM粒子解析，地域気象影響評価等に応用．⑤衛星データ検証ツールをNASA/AERONETデータを基に作成．⑥本成果は2017年12月に打ち上げのJAXA/GCOM-C（しきさい衛星）搭載SGLIセンサデータに適用予定．
• 衛星を用いた都市域におけるPM2.5濃度の広域分布推定

  日本学術振興会：科学研究費助成事業

  研究期間 : 2013年04月 -2016年03月 

  代表者 : 佐野 到; 向井 苑生; 中田 真木子

   

  衛星データに基づくPM2.5濃度分布推定に関する研究を実施した．PM2.5濃度推定のためには衛星観測値より推定するエアロゾルの光学的厚さ（AOT）情報が必要となるが，都市部のAOT推定は難しい．本研究では，温室効果ガス観測技術衛星(GOSAT)搭載CAIセンサによる反射率を用いて，大阪上空のAOT分布を導出した．NASA/AERONET DRAGON-Japan集中観測において取得した地上からのAOT計測値と比較した結果，良好な精度(RMS値)を得た．このAOT分布情報に基づくPM2.5濃度を推定した結果とβ線式PM2.5計測値との比較結果より，RMSが 約6μg/m3であることがわかった．
• 複合センサデータを用いた大気粒子光学特性導出法の精密化と評価

  日本学術振興会：科学研究費助成事業

  研究期間 : 2006年 -2008年 

  代表者 : 佐野 到; 向井 苑生

   

  複合センサ(ADEOS-II/GLI及びPOLDER)データを用いた大気粒子特性の導出を行った.GLIによる近紫外,可視波長データを利用し,炭素性エアロゾル識別を実施,エアロゾル種別を考慮した上で偏光情報により光学的厚さなどのエアロゾル特性を導出した.また,エアロゾル輸送モデルによる計算結果を併用したデータ解析も試みた.以上の結果,エアロゾル種の違いによる導出精度悪化を低減することができた.
• エアロゾルとPM_<2.5>の同期観測:エアロゾルの発生から移送拡散まで

  日本学術振興会：科学研究費助成事業

  研究期間 : 2006年 -2008年 

  代表者 : 向井 苑生; 佐野 到; 中口 譲; 保本 正芳; 井口 信和; 溝渕 昭二

   

  (1)NASA/AERONET放射計等による大気エアロゾル地上観測、(2)SPMのサンプリング計測と化学分析、(3)エアロゾル放射特性とSPM値の関係解析、(4)地上と衛星データの併合によるエアロゾルマップの導出等に関し、継続的に研究実績を挙げている. (5)2008年5月にNIESライダーネットワーク機器を設置し、(6)エアロゾルの発生から拡散までの解明、(7)総合的なデータ解析手法の実装、(8)モデルシミュレーションと実データの融合を実現した.
• エアロゾルの間接的地球冷却化効果

  日本学術振興会：科学研究費助成事業

  研究期間 : 2002年 -2005年 

  代表者 : 太田 幸雄; 村尾 直人; 山形 定; 佐野 到

   

  エアロゾルが気候に与える影響のうち、雲を通した効果、いわゆる間接効果を明らかにするために、鉱山廃鉱内に設置された人工雲実験施設(Artificial Cloud Experimental System,以下ACES)でエアロゾルが雲生成に与える影響について実験を行なった。実験は2002年から2005年まで毎年11月に岩手県遠野市の釜石鉱山日峰中央立坑内の高低差430mのACESで行なった。坑頂部分には上昇気流を発生させるためのファンが設置してあり、最大1.4m/secの上昇風速が得られる。ACES内は全高度に渡って梯子によってアクセス可能で、踊り場を利用した機器の設置、雲の観測が可能である。エアロゾルが水蒸気の凝縮により雲粒となるのは、坑底からの高度30m付近であること、高度100m付近では雲粒数がほぼ一定になっていることがわかったため、坑底から高度100mまでの地点で集中的に観測を行なった。 観測期間中、坑底気温は13.0℃前後で極めて安定していた。ACES内の温度プロファイルは、高度30m〜50mの雲が発生し始める高度で気温減率の小さな領域が観測された。坑底で、大気中に存在し雲核として作用すると考えられている硫酸アンモニウム、塩化ナトリウムなどを粒子として供給すると、雲水量は大きく変化しないまま、雲粒数濃度が増加し、雲粒径は減少することが実験的に確認された。上昇風速が増加した場合にも、雲粒数の増加が見られた。さまざまな気候影響因子の中で、エアロゾルの間接効果は現在最も不確定性の大きなものであり、ここで得られた実験結果は、エアロゾル数濃度と生成される雲数の濃度との関係を与えるパラメータとして大循環モデルに組み込むことが想定される。しかし、ここで得られた結果をそのままモデルで利用することは困難であるため、ACESでの結果をモデル利用可能な形に変換する方法についても検討した。
• 海・陸両域対流圏エアロゾル特性の解明-地球規模の大気環境解析システムの構築-

  日本学術振興会：科学研究費助成事業

  研究期間 : 2002年 -2004年 

  代表者 : 佐野 到

   

  衛星データを用いて,全地球規模での大気エアロゾル特性導出システムを開発した.本システムの特徴は偏光の取り扱いが可能という点である.衛星搭載偏光センサデータ解析が可能である.実際に,フランスCNESが運用するPOLDERセンサデータを利用しエアロゾル推定を全球規模で行った.解析実施期間はADEOS/POLDERが稼働した,1996年11月〜1997年6月,及びADEOS-2/POLDER-2が稼働した2003年3月〜2003年10月である.同期間のPOLDER-1/-2全レベル1データ(約6TB)を入手,解析を行い,全球におけるエアロゾル光学特性(波長0.55μmにおける光学的厚さ,オングストローム指数)を導出した.衛星データからの導出プロダクトは全地球規模で展開されたAERONET地上観測値と比較検証を行った.検証結果よりRMS誤差で0.1の精度で光学的厚さが導出されている.本導出結果より,特に中央アフリカ,インド北部,中国大陸において定常的に人為起源によるエアロゾル(焼畑燃焼,工業由来による小粒子)が大量に排出されていることが確認された. 和歌山県白浜,長崎県福江島,大阪府東大阪の3カ所にて放射計を設置し地上からのエアロゾル観測を実施した.特に白浜及び大阪は米国NASAが管轄するAERONETデータとして準リアルタイムに取得データがWebで公開されている.また福江のデータはSKYNETのデータとして,千葉大学のWebにて公開されている.本研究で取得する放射計データは,NASA/GSFC,及び,ハワイ島マウナロア山,マウイ島ハレアカラ山にて絶対検定を実施しており,その精度を0.01以下の誤差となっている.
• アジア太平洋域における大気エアロゾルの偏光観測

  日本学術振興会：科学研究費助成事業

  研究期間 : 2001年 -2004年 

  代表者 : 向井 苑生; 佐野 到; 保本 正芳

   

  得られた研究成果を以下にまとめる. 1.衛星データ解析によるエアロゾル・リトリーバル 従来の衛星による気リモートセンシングでは.放射輝度値(可視,赤外波長データ)を用いてきた.本研究では,ADEOS-I(1996-1997),ADEOS-II(2002-2003)衛星搭載のPOLDER偏光データを利用したエアロゾルの光学特性の導出(リトリーバル)に成果を挙げた.ADEOS-2/POLDERデータの取得により,2003年4月から10月の大気エアロゾルの全球規模分布図を導出した.ADEOS/POLDERデータの成果の比較から,1997年から2003年への大気エアロゾルの年変化を把握できた.同時に,エアロゾルと深く関連する雲粒子特性や水蒸気量の全球分布を導出し,相互の関係を求めた. 2.地上観測とデータ解析 衛星データから得られるグローバルな成果を有効に活用するためには,ローカルな地上観測による検証を行なわねばならない.1996年よりポータブル型多波長偏光放射計を導入し,日本各地での上空大気光の偏光観測と太陽直達光観測に着手してきた.また,近年では日本に限らず広く大気偏光放射観測を実施するに至っている.さらに,エアロゾルは空間変動だけではなく,時間的な変動も大きい.時間変化を捉えるには長期的な定点観測が必要である.本研究グループは,エアロゾル観測ネットワークNAS/AERONET,SKYNETサイトに参加している.下記に,観測成果をまとめる. (1)近畿大学本部キャンパス(東大阪)常時集中観測 (2)NASA/AERONET放射計,SKYNET/Sky-radiometerによる観測 (3)APEXフィールドキャンペーンに参加 (4)海洋観測船「みらい」での観測に参加 (5)偏光放射計の機器校正 (6)日本近海での大気観測
• 藻場造成が可能な多孔質複合材料の開発

  日本学術振興会：科学研究費助成事業

  研究期間 : 2001年 -2004年 

  代表者 : 玉井 元治; 向井 苑生; 佐野 至; 江口 充; 来田 秀雄; 竹田 英章; 吉田 宗久

   

  本研究は,貧栄養化した海域や磯焼け現象によって藻場が消失した浅海域に,藻類に適した栄養分を強化したセメント系の多孔質複合材料(ポーラスコンクリート)を沈漬し、藻類を早期に再生する方法を提供した。さらに,藻場が消失している海域の調査と前記のポーラスコンクリートを設置した海域の衛星観測データを用いた管理方法を開発した。 具体的には、ポーラスコンクリートの製造法と強度や耐久性につき明らかにし、海藻類の成長に効果がある無機質の栄養素(鉄分・窒素及び燐成分等)を特殊なポリマー等によりシールし,ポーラスコンクリート内に挿入して沿岸海域に沈漬し,それらの栄養源を徐々に海域に溶出させ,藻場を造成する方法を提案した。また,自然海域に沈漬した藻類付着基盤材料の物理的及び化学的変化や海藻付着と内外部に付着する生物種と量の長期的な遷移状況や多様性生物に及ぼす影響等を継続して総合的に調査・検討した。更に栄養強化したポーラスコンクリートによる藻場造成術と衛星観測データから海洋表面のクロロフィル濃度分布を導出する研究結果を活用し,栄養強化したポーラスコンクリートを利用した藻場造成を効果的に行う方法と,その後の経過を管理する手法を研究した。 平成13〜16年度の研究内容と研究成果は、それぞれ以下の内容である。 1)多孔質複合材料であるポーラスコンクリートの製造法と各種物性につき調査した。特に、粗骨材に付着する結合材の分離性状を明らかにした。 2)藻類付着基盤材料(ポーラスコンクリート)の長期的な物理変化や水域における耐久性の程度を把握した。特に,水中での遊離石灰の溶脱による耐久性や砂礫による摩耗特性について調査した。 3)粒状化した窒素や隣成分を特殊なポリマーシールする方法を示し、藻類付着基盤材料から溶出する栄養塩類の制御方法を継続研究した。 4)各種リサイクル材料を用いた藻類付着基盤材料への海藻類や小動物などの付着生物の遷移状況を調査した。 5)海域で観測したクロロフィル濃度と衛星観測から測定した観測データの整合性を図るため,実海域での調査や観測データの収集と解析を行った。
• 全球規模の大気エアロゾルに関する光学的基礎データ導出と検証実験

  日本学術振興会：科学研究費助成事業

  研究期間 : 2000年 -2001年 

  代表者 : 佐野 到

   

  本年の研究実績は次のとおりである. ○地上・洋上からの大気エアロゾル観測 大気エアロゾル観測をサンフォトメターや偏光放射計を用いて測定した.本年の重点的な観測は4月から5月にかけて行われたAPEXとACE-ASIAである.APEXは主として奄美大島笠利町を中心に行われ偏光放射計を用いた観測を行った.また,同時期に能登半島柳田村で自動型放射計をACE-ASIA国際エアロゾル同定キャンペーンの一部として臨時設置,運用した.大阪,和歌山県白浜においては定常的に運用していており,観測結果はhttp://aeronot.gsfc.nasa.govにて随時更新されている. 2000年10月〜現在 白浜 AERONETサイトとして大気観測(定常運用) 2001年4月 奄美大島 APEX-E2キャンペーン一部 2001年4月〜5月 能登半島 ACE-ASIAキャンペーン一部 2001年8月 モンゴル 千葉大との共同観測 2001年8月〜12月 Cimel偏光放射計のキャリブレーション(NASA/GSFCにて) 2001年11月〜12月 赤道太平洋洋上 海洋科学技術センター観測船「みらい」による大気観測 2001年12月〜2月 東大阪AERONETサイトとして大気観測(定常運用) 2002年3月 偏光放射計PSR-1000並びに全自動偏光放射計(Prede)のキャリブレーション(米マウナロア山)とエアロゾル高度分布観測 通年 東大阪 近畿大学キャンパス屋上にて大気偏光観測 ○衛星データを用いた大気エアロゾル導出 ADEOS/POLDERデータを基に,エアロゾル特性導出精度向上のための地表面からの偏光情報が違う,砂漠域,森林域,海域に分割し,また標高情報を加味したエアロゾル情報を全地球規模で導出した.また,地表面偏光を直接測定するための計測器作成準備を行った.
• 地上及び衛星偏光観測に基づく大気エアロゾル特性の広域分布図作成

  日本学術振興会：科学研究費助成事業

  研究期間 : 1997年 -1998年 

  代表者 : 佐野 到

   

  本年度の実績は,次の2つに大別できる. 1) 地上からの大気エアロゾル観測. 2) 衛星データに基づく大気エアロゾル特性全球分布作成とその季節変化調査. 1)の地上観測は,陸(近畿大学上空)を中心とし,偏光及び光学的厚さの測定を行った.また,解析時に必要となる観測時における気象データに関しても,同時収集を行なった. 2) 1)の解析システムを応用し,宇宙開発事業団より打ち上げられた,みどり(ADEOS)衛星搭載の偏光センサー(POLDER)データ処理用のシステムを作成した.センサー稼働期間の1996年11月から1997年6月のうち,季節変化の見込まれる1996年11月,1997年1月,4月の全観測データについて解析を行なった.解析結果を用い,各月における大気エアロゾル指標である光学的厚さ(Optical Thickness of Aerosols)とオングストローム指数(Ångstrom Exponent)の全球分布図を作成した.その結果,場所,季節による大気エアロゾル指標に大きな違いが見られた.具体的には,冬季の11,1月においては,アフリカ西岸から大西洋にかけて,サハラ砂漠起源のエアロゾルの吹き出しを導出できた.また、4月のアジア地域においても,ゴビ砂漠,タクラマカン砂漠起源である黄砂粒子によるエアロゾル粒子の飛来が明瞭に導出できた.これらは,他研究者が他センサーデータを用いて行なった解析結果とも一致し,精度良い広域エアロゾル特性分布図を作成できた.これらは気候変動モデルにおける地球大気放射収支計算,特に温暖化シミュレーションの精度向上のための基礎データとしても利用可能である.
• 大気-海システムにおける放射輸送と粒子形成に関する研究

  日本学術振興会：科学研究費助成事業

  研究期間 : 1997年 -1997年 

  代表者 : 向井 苑生; 佐野 到

   

  本研究は地球環境システムに大きな影響を及ぼす大気-海洋間の放射輸送過程のモデリングとシミュレーションを理論・観測両面から実現しようとするものである. 具体的には,大気放射輸送の鍵を握る大気エアロゾルの光学特性導出アルゴリズムを提案し,ADEOS/OCTS,POLDERの近赤外波長データを用いたエアロゾル・リトリ-バルに成果を挙げている.特に,通常用いられてきた散乱光強度だけではなく,新たに偏光度をも併用して,精度の向上を図った.今年度は特に,地球大気モデルの精密化を目指し,上記大気エアロゾルモデルの検証に加え,大気の垂直構造の影響・地上物体や海陸境界域における周辺効果の見積もり・海および海面モデルの再構築を考慮した. 総合的な放射輸送システムを構築するには,種々のデータセットが必要である.大気エアロゾルモデルを含む地球大気,海洋(陸)などに関するデータセット,多重散乱計算結果のデータベース,更に,開発アルゴリズム検証のための実験及びテストデータも必要となる.これらのデータは併せて,地球大気基礎データベースとして有用なものになる.データ及び計算機システムは,当研究室にて稼働中である.シミュレーションに際し,汎用性・更新性の高い柔軟な構造を持つソフトウエアの開発に留意した.
• 偏光シミュレーションに基づく大気エアロゾルモデルの導出

  日本学術振興会：科学研究費助成事業

  研究期間 : 1995年 -1997年 

  代表者 : 向井 苑生; 佐野 到

   

  本研究ではADEOS衛星に搭載されている複数センサーデータを相互利用する事により,効率的でより正確な大気エアロゾルの光学特性導出アルゴリズムを提案した.具体的には,近赤外波長でのADEOS/OCTS,POLDERデータを用いたエアロゾル・リトリ-バルに成果を挙げている.特に,エアロゾル・リトリ-バルの精度を上げるため,散乱粒子の偏光特性を観測・実験・理論面から解析し,ADEOS(及びそれ以降の)衛星への応用のための効率的な実働システムを開発した.更に,検証実験として,船舶および地上から大気エアロゾルの偏光測光を実施している. 得られた大気エアロゾルモデルを含む地球大気,海洋(陸)などに関するデータセット,多重散乱計算結果のデータベース,更に,開発アルゴリズム検証のための実験およびテストデータも必要となる.これらのデータは併せて,地球大気基礎データベースとして有用なものになる.データ及び計算機システムは,近畿大学地球環境工学研究室にて稼働中である.
• 偏光放射観測に基づく地球大気エアロゾル特性の解析

  日本学術振興会：科学研究費助成事業

  研究期間 : 1996年 -1996年 

  代表者 : 佐野 到

   

  本研究では,大気エアロゾルの光学特性(化学組成,密度,大きさ等)の時空間変化からその起源や分布を調べた.エアロゾル光学特性の導出にあたり,放射強度と合わせて,偏光度を利用した.偏光度データの取得には,下記のスケジュールで多波長偏光放射計(PSR1000)を用いて検証実験を実施した. ●平成8年5月〜平成9年2月 近畿大学(東大阪市) ●平成8年5月〜平成9年1月 気象庁気象研究所(つくば市)にて気象研,金沢工大と共同観測 ●平成8年7月,平成9年3月 神戸商船大学深江丸にて四国・九州沖にて洋上観測 これらの取得データを基に,光散乱シミュレーション値と比較照合から最適なエアロゾルモデルの導出を行った.得られた結果を次に記す. 1)つくば市上空,東大阪市上空の陸域のエアロゾルに関しては,有機物溶存型エアロゾル(Water Solubleタイプ)と,都市型エアロゾルとしての煤(Sootタイプ)などが混合している.また,エアロゾル粒径半径と分布は,変化が激しい. 2)大阪湾など,瀬戸内海上空では海塩粒子(Oceanicタイプ)と共に,陸域起源の有機物溶存型が混合している. 3)太平洋上では,ほぼ海塩粒子に限られ,エアロゾル粒径分布変化はほとんど無かった. 本研究と通じて,人的な影響だけでなく大陸と海洋の影響を受けた日本近海の大気エアロゾルの地域的な分布状況や,粒径変化が分かった.

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