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Estimation of the temporal and spatial distribution of the optically thin Asian dust from satellite image data

根据卫星图像数据估计光学稀亚洲尘埃的时空分布

基本信息

批准号：
16510011
负责人：
KUSAKA Takashi
金额：
$ 2.18万
依托单位：
KANAZAWA INSTITUTE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16510011/
关键词：
Asian dust Polarization measurement Optical thickness of Asian dust POLDER polarization data Atmospheric aerosol Ground reflectance Inverse problem Long-range transport of Asian dust 黄砂の偏光度 ADEOSII POLDER 黄砂の光学的特性シミュレーション大気偏光度デ

项目摘要

In general, it is very difficult to identify the widely spread hazy dust cloud in satellite images over the land surface. In this study, a new method for estimating the temporal and spatial distribution of the optically thin Asian dust was developed.(1)Polarization measurements of the sky radiation by the multi-spectral polarimeter have been carried out at the ground station in Kanazawa city, Japan from March to May in 2000 to 2005. In this study, (i) Web application system for retrieving degrees of polarization from the database of polarization measured properly by the polarimeter was made, and (ii) the method for estimating optical properties of Asian dust, such as the optical thickness, the number size distribution and the refractive index, and the ground reflectance from polarization data measured at angles of 75, 90, 105 and 120 degrees from the solar direction in the principal plane was developed.(2)A new algorithm for estimating optical properties of the hazy Asian dust and the ground reflectance simultaneously from ADEOSII/POLDER data over the land surface received at a single channel was developed. In order to evaluate the algorithm, degrees of polarization measured at the ground station are compared with those estimated from ADEOSII/POLDER data on May 3, 2003. As a result, it was found that the values of optical parameters of Asian dust estimated at the 670nm channel provide reasonable ones.(3)In order to estimate the temporal and spatial density distribution of Asian dust over East Asia, the long-range transport simulation model of dust particles was used. The released region and mass flux of Asian dust was determined such that the concentration of Asian dust obtained from the long-range transport simulation is almost equal to that of SPM (Suspended Particulate Matter) measured at various places in Japan.

一般来说，在陆地表面的卫星图像上很难识别出广泛分布的雾霾云。本研究发展了一种估算亚洲光学薄沙尘时空分布的新方法。(1)利用多光谱偏振仪对2000年3月至2005年5月在日本金泽市地面站的天空辐射进行了偏振测量。(1)建立了从偏振仪测量的偏振度数据库中提取偏振度的Web应用系统；(2)开发了从与主平面太阳方向成75度、90度、105度和120度的偏振数据估计亚洲尘埃的光学厚度、数量尺寸分布和折射率等光学性质以及地面反射率的方法。(2)发展了一种从单通道接收的陆地表面ADEOSII/POLDER数据同时估计亚洲灰尘的光学性质和地面反射率的新算法。为了对算法进行评估，将地面站测得的偏振度与2003年5月3日的ADEOSII/POLDER数据估计的偏振度进行了比较。结果表明，在670 nm波段估算的亚洲沙尘光学参数值是合理的。(3)为了估算亚洲沙尘在东亚上空的时空密度分布，采用了沙尘粒子长程输送模拟模式。确定了亚洲沙尘的释放区域和质量通量，使长程输送模拟得到的亚洲沙尘浓度与在日本各地测得的悬浮颗粒物(SPM)浓度几乎相等。