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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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).

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.

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.

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.

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.

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.

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.

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.

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.

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 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).

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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 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.

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.

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.

[1] The cloud flag algorithm, which uses the data of near infrared wavelengths, sometimes flags the turbid water region as clouds. A classification method of the cloud-free pixels over the turbid waters from the cloud-flagged data is proposed. SeaWiFS data around the western coast of India and other turbid water regions (La Plata River, East China Sea) are examined for our proposed algorithm.

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.

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.

[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.

Ocean color analysis and aerosol retrieval in coastal regions are made difficult by water turbidity. An algorithm has been proposed which uses the data at a blue wavelength instead of those in near-infrared wavelengths for the aerosol retrieval. The quasi-homogeneous effects are assumed for the correction of water leaving radiance with soil particles at 0.412 μm. The proposed algorithm is examined using SeaWiFS data on December 24, 2000 around India. Over the coastal waters, extremely large values of optical thickness are extracted from the operational SeaWiFS algorithm, whereas our proposed algorithm produces a smooth transition in values of optical thickness from the turbid waters to the surrounding regions.

OCTS and POLDER sensors were launched on ADEOS satellite in August 1996. It is well known that combination of multi-sensor data is useful to retrieve the physical properties of the Earth atmosphere from space. In this work, a procedure for cloud detection and distinction of thermodynamic phase of the top cloud is proposed based on the combined use of ADEOS/POLDER and OCTS. In practice, thermodynamic phase is distinguished by using polarized reflectance at 0.865 mum given by POLDER and brightness temperature at 10.9mum by OCTS. Further effective radius of water cloud particles is extracted from comparison of light scattering simulations with the polarization measurements by POLDER. In this work POLDER and OCTS data of Nov. 10, 1996 are examined. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.

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.

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。

Comparison and combination of OCTS and POLDER, which are sister sensors mounted on the satellite ADEOS, are considered from a viewpoint of aerosol retrieval. First it is shown that the latest in-flight calibration coefficients for each sensor provide better consistency between two sensors. Then aerosol characteristics are extracted from the OCTS level-1 b data and POLDER level-1 data respectively. From comparison of both results in respect of the retrieved aerosol properties, we found that Angstrom exponent of aerosols is more strongly affected by the fluctuation of radiance than the aerosol optical thickness is. In other words, it is impossible for Angstrom exponent to avoid the influence of observational error in radiance. (C) 2001 COSPAR. Published by Elsevier Science Ltd, All rights reserved.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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

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。

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．

This study aimed at performance of efficient system for aerosol retrieval based on the satellite data utilized together with ground-based measurements, radiative transfer algorithms, and the numerical model simulations. Summary of this work is as follows: Improved description of aerosol models, and validation it by using Terra/MODIS and ADEOS-2/GLI. 2. Development of radiative transfer system for polarization or non-polarization field. 3. An absorbing aerosol index (AAI) has been proposed defined as the ratio of the satellite-observed radiance at a wavelength of 412 nm to that at 380 nm in order to detect the absorbing particles. 4. Application for air pollution, PM analysis and an impact on the environment and climate change. 5. Validation system for satellite observations based on NASA/AERONET data. 6. The obtained results in this study are available for JAXA/GCOM-C/SGLI and other future missions.

This work intends to develop a procedure to estimate PM2.5 concentration over mega city in Japan. The procedure is composed of two parts as: 1. Aerosol retrieval from satellite reflectance measurements. 2. Conversion into PM2.5 concentration from retrieved aerosol optical thickness (AOT). The comparison of retrieved AOT from GOSAT/CAI with NASA/AERONET AOT measurements is performed in Osaka region. As results, a root mean square error value of AOT (RMSE-AOT) is around 0.09 in all retrieved wavelengths and the RMSE-AOT at a wavelength of 670 nm over Osaka region is around 0.07. Finally, satellite retrieved PM2.5 concentration also coincides with in situ PM2.5 measurements, RMSE-PM2.5 is around 6 ug/m3.

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.

(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.

For evaluation of indirect effects of aerosol particles on climate, field experiments, named with Magic Monkey Project (MMP), were carried out in Artificial Cloud Experimental System (ACES) established in an abandoned vertical shaft with 430m depth in Kamaishi Mining Co. in Iwate pref., Japan. The experiments evaluating the influence of the number concentration of (NH4)2SO4/NaC1 aerosol particles on the properties of resulting cloud droplets were performed in November every year from 2002 to 2005. At the top of ACES there were two fans which made updraft inside ACES at the maximum 1.4[m/sec]. In the ACES any favorable altitude for measurement are accessible by ladders settled from the bottom to the top. Cloud droplets were visible around 30m above the bottom. Aerosol particles of ammonium sulfate and sodium chloride were generated at the bottom of ACES by atomizers into the air. According to the results obtained in the preliminary experiments intense measurements were carried out between the bottom and the altitude of 100m from there. Cloud droplets were sampled by impactors at several altitudes. Inside ACES the temperature is very stable around 13.0 degree Celsius at the bottom. Temperature profiles in the ACES showed that temperature lapse rates were small around 30-50m above the bottom of ACES where cloud generation started. When aerosol particles, such as ammonium sulfate and sodium chloride, were generated at the bottom, the number concentration of cloud droplets increased and their diameter decreased keeping the amount of liquid water contents almost constant. Among the parameters influenced to change the climate, the indirect effect of aerosol is the one with largest uncertainty. Although the results obtained here are envisioned to be used in a general circulation model (GCM), we can not use those result directly. The procedure to modify the obtained results for GCM model was also considered.

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.

The obtained results during this search period from 2001 to 2004 are as follows ; 1.Aerosol retrieval using satellite data The global distribution of aerosols are obtained by using polarization data together with radiance data derived from ADEOS/POLDER in 1997 and 2003. The basic idea of our aerosol retrieval is that the scattering behavior of aerosols plays a sufficient role in the polarization field of the Earth atmosphere-surface system in the near infrared wavelengths. It is shown that the aerosol loading increases from 1997 to 2003, and aerosol events, which means anomaly lots of aerosol loading, are shown in north-west Africa and east Asia. 2.Ground based photo-polarimetry of aerosols To characterize urban aerosols, sun/sky photometry and polarimetry with PSR-1000 (Opto Research) have been performed over Higashi-Osaka since 1996. Multi-spectral photometer CE-318-2 (Cimel Electronique) was subsequently set up for an AERONET site in 2002. Another AERONET instrument (CE-318-1) has been operating at Shirahama since 2000 as a part of NASA/AERONET. The radiometers at both Osaka and Shirahama were calibrated using a standard AERONET procedure. The new SPM-613D instrument makes it possible to determine the relationship between aerosol properties and the particulate mass

The purpose of this study is to develop the method for the early recovery of the biodiversity in the oligotropical coastal area. It is of importance in the recovery of the biodiversity to make kelp forest grow in the concerned area. In order for it, sufficient nutrient is required as well as the proper seedbed. Hence, in this study, granulated fertilizer, which contains nutrient, such as nitrogen, phosphorus and iron, is coated by the special polymer, and then, is mixed into the porous concrete in order to provide seedbed and nutrient simultaneously. The physical and chemical properties of porous concrete with granulated fertilizer are discussed. Then brief note is appended to describe the method to select the place of implantation and to control the implantation with the aid of the artificial satellite to measure the chlorophyll concentration on sea surface. Research results from 2001 to 2005 are as follows. 1)Manufacturing method and rheological properties of binder and also segregation of fresh porous concrete (POC.) 2)Physical and chemical properties of porous concrete (POG)., and clarified the durability of freezing and thawing, washout test by water and abrasion by grain in sea 3)Properties of POC mixed with fertilizer and converter slag in seawater. 4)Seaweed adhesion onto POC mixed fertilizer and converter slag. 5)Water purification performance of POC. 6)Properties and seaweed adhesion of POC using the recycled material. 7)Chlorophyll concentration of sea surface and consistency of data measured from satellite observation.

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.

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.

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.

We intend to develop efficient algorithms for aerosol retrieval. Our algorithm is based on an idea that aerosol characteristics can be estimated in terms of the scattering behavior. Polarization feature strongly depends on the aerosol characteristics, e.g.refractive index, size, or shape of aerosols. An efficient algorithm for aerosol retrieval is developed by considering simulations in the polarization field. Thus it is our purpose to continue our photopolarimetric measurements of aerosols and simultaneously simulate polarization field. The ground truth including research vessel observations have been undertaken for these four years. Certainly new satellite data by both of ADEOS/OCTS and POLDER are available to compile the global-scale aerosol distribution. The following products have been compiled ;

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.