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A yellow dust event with moderate strength was observed on 9 April 2012 at Sendai in North part of Japan. Backward trajectory calculations with NOAA HYSPLIT showed the complex flow of aerosols into the North Japan. The sharp edge of this dust cloud was recognized by the data taken at several observatories, and the dust cloud conducted by low pressure system had heterogeneous structure, therefore very complicated interaction among aerosols may occur. Mie scattering lidar data was used to reproduce the radiative effect caused by this yellow dust event at Sendai with radiative transfer model. The results estimated every 15 minutes of radiative forcing at the top of the atmosphere and at the bottom of the atmosphere. The results show the slight warming effects < 6.5 W/m2 during night time both at the top and the bottom of the atmosphere, and during day time the large cooling effects < 150 W/m2 at the bottom and < 60W/m2 at the top of the atmosphere.

Meso-scale atmospheric models outputs are valuable data for cloud and aerosols retrievals. In view of the launch the Global Change Observation Mission-Climate/Second generation Global Imager (GCOM-C/SGLI) satellite, atmospheric models products are tested against satellite observations data in order to evaluate the degree of reliability and the sensitivity of these models outputs to variations of atmospheric conditions. The analyses presented in this study are based on two models outputs: the Nonhydrostatic Icosahedral Atmospheric Model (NICAM) and the National Center for Environmental Protection/Department Of Energy (NCEP/DOE) re-analysis-2 data. Terra/Moderate Resolution Imaging Spectrometer (Terra/MODIS) satellite sensor observations of water vapor radiances are used as the verification data set for the tests conducted. These tests are based on the comparison between upper tropospheric water vapor properties (clear sky and above-low clouds) observed by satellite and radiative transfer forward calculations (using models' predicted atmospheric profiles, the satellite sensor spectral response and geometrical characteristics) derived from NICAM and NCEP/DOE. The parameters measured are the upper tropospheric brightness temperature (UTBT) and relative humidity (UTRH). Discrepancies between simulated data and observations are analyzed in terms of atmospheric instability, cloud convection movements and, effective emissivity. The results obtained show that both NICAM and NCEP/DOE simulated UTBT and UTRH outputs have a relatively comparable distribution pattern. However, simulations performed with the NCEP/DOE outputs present generally fewer discrepancies with satellite observations. For the interpretation of these results, the stability index study shows that differences between models and observation data tend to be high in unstable atmospheres. This atmospheric instability can be attributed to cloud convection processes affecting areas adjacent to convective clouds. As the amount of convective clouds increases, the errors in the water vapour depiction by the models increase also. Analyses of heat movements studied through the variation of the cloud effective emissivity suggest that the discrepancies between the observations and the models increase with the decrease of the clouds' effective emissivity. Adjustments of some of the models parameters, notably the microphysical parameterization of the clouds resolving scheme, are suggested in order to improve the accuracy of the models' results.

Geostationary satellites are well suited for radiation budget computations due to their high temporal resolution. In order to validate satellite observations and the radiative properties derived from the GMS-5/SVISSR, we compared its cloud optical depth (COD) with that from the polar orbiting satellite, TERRA/MODIS. It appears that there's a good agreement between both COD sets in thin cloud areas while, major differences (MODIS COD higher) occur in thick cloud regions. Factors affecting accurate observations of clouds by satellites range from the solar and satellites geometries to the sun-cloud scale of interaction. This study focuses on the latter effect, as the solar and satellite zenith angles are relatively low in the area and time selected. The sun-cloud interactions refer here to the three-dimensional radiative effects (e.g. asymmetry, smoothing) due to the horizontal spatial variability of clouds and their structural inhomogeneity. These are analyzed through the IR thermal gradient and small areas' standard deviation (STDEV) respectively. By combining these two parameters, it is possible to reasonably explain the differences in cloud physical and optical properties noticed between both satellites. Results show that, asymmetry and smoothing effects seem to be stronger for SVISSR data than MODIS. At the sides of the clouds SVISSR observed cloud properties are more or less comparable to MODIS data. At the top of the clouds, SVISSR data are systematically lower and do not match MODIS data. SVISSR observations fail to detect cloud inhomogeneity mostly at the top of the clouds, and therefore seem to underestimate the cloud optical properties.

We developed a low-power and high-sensitivity cloud profiling radar transmitting frequency modulated continuous wave (FM-CW) at 95 GHz for ground-based observations. Millimeter wave at 95 GHz is used to realize much higher sensitivity than lower frequencies to small cloud particles. An FM-CW type radar realizes similar sensitivity with much smaller output power to a pulse type radar. Two 1m-diameter parabolic antennas separated by 1.4m each other are used for transmitting and receiving the wave. The direction of the antennas is fixed at the zenith. The radar is designed to observe clouds between 0.3 and 20 km in height with a resolution of 15 m. Using the developed millimeter-wave FM-CW radar at 95 GHz, we observed clouds in a campaign observation in Amami Island in March 2003, and on a sail on Mirai, a Japanese scientific research vessel, in September 2004 to January 2005 in the Arctic Ocean and the southwest of the Pacific Ocean. The radar provided good and sensitive data in these long-term observations.

A Mie lidar was used to make observation of Asian dust over Hefei (31.90° N, 117.16° E) in the every spring from 1998 through 2004. This paper presents main features of vertical distribution and temporal variation of Asian dust extinction coefficient at 532 nm wavelength during the seven years. There were two kinds of vertical distributions of Asian dust extinction coefficients. One indicated that the Asian dust particles intruded into the local boundary layer, causing the very thick dust layer with depth of about 3-4 km. The other showed that the Asian dust passed over Hefei area just above the boundary layer. The aerosol extinction coefficients in the elevated dust layer within the middle troposphere from 3 to 6 km were unusual large. Seasonal average aerosol extinction coefficient profiles showed that larger aerosol extinction coefficients from 1 km to 10 km altitude range were observed in the springtime rather than in any other season.

The data analyses of the ADEOS-II (Midori-II) GLI data have started. The optical and microphysical properties of warm water and cold ice clouds were retrieved by use of originally developed GLI data analysis algorithms. On the one-month mean results of warm water cloud in April 2003, very thick cloud optical thickness appeared in the east coast of the North America, the East Europe, and the South-East Asia. The moderately optically thick area spread over the Atlantic Ocean and West to Middle Pacific oceans. The effective radius was smaller on the continents and coastal area than ocean area. Especially, the South-East Asia to the middle pacific area where often covered with aerosols coming from continent in April, is the region of the smaller cloud effective particles. For the cirrus clouds, the smaller effective radii and larger effective radii can be obtained in low-to-mid and mid-to-high latitude area, respectively. Very low cloud top temperatures around 210K were often observed in the tropics. Warmer cloud top temperatures ranging from 220 to 240K were widely seen both over continental and oceanic area in mid-to-high latitude area.

Water vapor is one of the most significant green house effect gases. A monitoring of water vapor behavior with operational satellite is important to investigate the global changes. Water vapor usually exists at lower troposphere. However, precipitable water is a key property to comprehend the variation since sometimes humid air mass moves to the upper troposphere. Using split window channel data with optical sensors such as AVHRR and VISSR, several retrieval algorithm has been proposed and among them, transmittance ratio method has been often utilized. However, the approach is still controversial because some studies concluded it was available and others not. We investigated the availability of the method with split window channels' data of GMS-5/VISSR on a semi-continental scale. A calibration curve of the precipitable water with radiosonde observation had been made in course of the retrieval procedure. However, the calibration curve are hardly sensitive to the precipitable water. Numerical simulations were carried out for the possible condition, and it turned out that calibration was insensitive to precipitable water under some condition at all: larger water water variation for a given surface temperature range within a given region. The results of a feasibility study will be discussed.

A quasi real time system for estimate of the surface solar flux is introduced. The system will start to be operated in this year, and provide the solar flux until tomorrow’s morning. The system uses 0.09-degree resolution products from the GMS-5 image data of CEReS, Chiba Univ. It also uses the six-hourly atmospheric objective analysis data from the Japan Meteorological Agency. The solar flux is estimated at each pixel. This system includes four steps to estimate the surface solar flux. (1) The first step discriminates cloud pixel from clear one. The adopted method is similar to ISCCP, in which the reference Tbb for discrimination is created by data before and after the target day. In this system, it is impossible to use tomorrow’s data, because real time operation is needed. Therefore historical data is used to create the reference. (2) Cloud pixel is analyzed using 11/12 micron split window methods and 6.7 micron channel. The methods determine that the pixel is water or ice cloud, and derives the optical thickness for ice cloud. (3) The optical thickness for water cloud is retrieved from the reflection method using visible channel with assumption of the effective radius. (4) Cloud optical thickness and atmospheric information is converted to the surface solar flux from the package RSTAR5B for radiation transfer calculation. The surface solar flux using typical pixels from 0.5-degree grid area had been already derived. A comparison of satellite derived solar flux and the surface observation shows fair result in clear sky days, and overestimate in cloudy days.

SeaWiFS observation of the East-Asian seas during the Aerosol Characterization Experiment-Asia shows large areas of under-estimated or even negative water-leaving radiance in the blue. To investigate it, three match-up stations were analyzed. An iterative radiative transfer simulation was carried out, in an attempt to reproduce the satellite measured top-of-atmosphere reflectance. The resulting water reflectance and aerosol optical thickness (AOT) agreed well with field measurements when the effect of sub-micron absorbing particles was considered in the simulation. The error in the retrieved water reflectance was much decreased, with average values of about 6% at 412nm and 443nm for the three stations. The effect of the Asian dust was also simulated in comparison with that of small absorptive aerosols. The under-estimation could not be solely attributed to Asian dust. It was also found that at one of the station, where the presence of dust aerosols was anticipated, an aerosol model mixed with both dust and soot improved the accuracy of the estimated AOT compared with the case of soot as the only absorptive aerosol. Sub-micron absorbing particles, in addition of the Asian dust, should be considered in the optical remote sensing of East-Asian waters.

A cloud profiling radar transmitting frequency-modulated continuous wave (FM-CW) at 95 GHz is developed for ground-based observations. Millimeter wave at 95 GHz is used to realize high sensitivity to small cloud particles. Two 1m-diameter parabolic antennas separated by 1.4m each other are used for transmitting and receiving the wave. The direction of the antennas is fixed at the zenith. The radar is designed to observe clouds between 0.3 and 15 km in height with a resolution of 15 m. The system was integrated and sensitivities and stabilities have been measured. Results of test measurements of clouds show that the system is sensitive and stable enough to observe various clouds.

The atmospheric correction in ocean color remote sensing ins the most significant technique to retrieve the water leaving radiances, which are less than 10 percent of the satellite radiances, and its main errors are occurred by the estimation errors of the aerosol property and quantity which are highly variable in both space and time. In this study, our main purpose is to develop the advanced atmospheric correction method by using multi-viewing satellite data. POLDER onboard ADEOS can acquire multi-direction reflectance up to 14 viewing angles. In order to evaluate the validity of the multi-angle algorithm, we tired to test the algorithm with POLDER data. Results of comparisons with OCTS algorithm show that this algorithm with 3 or 4 angles POLDER data is available to estimate the aerosol properties because it is not affected form the errors depend on the band ratio.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Changbai mountain is a very important natural reserve in China as well as in the world, because it possesses a high bio-diversity, and is a typical ecosystem representing boreal vegetation. Few studies on the dynamic-equilibrium of forest in relation with natural disturbance have been reported. In this study, the change of forest vegetation in the reserve was detected by using Landsat TM images. Image differencing between 1984 and 1997 was adopted to derive new images that indicate cover type change. The natural forest in the reserve was in a status of relative equilibrium. The number of pixels with decrease in radiance was nearly the same as those with increase in radiance. It is demonstrated that the so-called climax is not a pure stand which is generally assumed to be exclusively dominated by climax species, but a complex of mosaic structure that consisted of patches in different stages of succession. This climax structure was maintained by natural disturbance like fall. The pioneer patches are permanent units in the forest community. Gaps are frequently created, and thus the pioneer patches are kept constantly. As a whole, TM imagery is effective for detecting vegetation changes, but tiny gaps with several pixels are difficult to discriminate from noise. The change inside the natural reserve was minor, while the vegetation outside the natural reserve presented an upgrading status, showing the recovery after timber cutting.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The scattering phase function angular characteristics, including the effects of particle nonsphericity on the phase function and the uncertainties using the Henyey-Greenstein approximation for hexagonal ice crystals are investigated systematically. Some new and significant facts are obtained.