亚洲地区MODIS和Himawari-8细模态气溶胶产品验证及其时空分布分析

利用AERONET观测网数据,结合MODIS(中分辨率成像光谱仪)及Himawari-8(新一代地球同步气象卫星)的气溶胶产品分析了亚洲41个站点2015—2016年细模态气溶胶光学特性.结果表明,MODIS和Himawari-8反演气溶胶细模态比例(FMF)及细模态气溶胶光学厚度(fAOD)落在误差区间EE(期望误差)内的比例均不超过80%,其中8个典型站点则不超过50%,总体上MODIS要优于Himawari-8,但与AERONET地基观测资料相比还存在一定的误差.因此,需要进一步研究反演方法,提升地表反射率的确定精度,从而提高卫星遥感反演精度.通过季节平均的比较,发现春、夏、秋、冬四季MODIS和Himawari-8的反演值均有所低估,MODIS fAOD各季节平均偏差相对较小.Himawari-8 FMF秋季在Dhaka_University站的平均偏差较大,MODIS FMF春、冬季的平均偏差最大值相对较大,夏、秋季则相对较小;对于同一站点在相同季节均为Himawari-8 fAOD偏差较大,并且MODIS fAOD各季节的平均偏差最大值均小于Himawari-8 fAOD的偏差值.同时,利用卫星观测分析了亚洲地区FMF和fAOD年均及季节平均分布特征,发现MODIS和Himawari-8 FMF年均分布高值区主要位于华北平原、东北平原、四川盆地和中南半岛,MODIS fAOD年均分布高值区主要位于中南半岛,Himawari-8 fAOD年均值则普遍较低.MODIS FMF和fAOD季节平均分布呈现出夏秋高、春冬低的趋势,Himawari-8 FMF和fAOD季节平均分布则呈现出春秋高、夏冬低的特征,高值区的位置和量值均有明显的季节变化.

Validation and temporal spatial distribution analysis of MODIS and Himawari-8 fine mode aerosol products in Asia

Fine mode aerosol optical properties were analyzed using 41 AERONET stations data, MODIS (Moderate Resolution Imaging Spectrometer) and Himawari-8 (new generation of geostationary meteorological satellite) aerosol products in Asia from 2015 to 2016. The results showed that the ratio of FMF and fAOD falling within EE were less than 80% for both MODIS and Himawari-8 aerosol products. In addition, the validation in 8 typical AERONET stations, the ratio of FMF and fAOD falling within EE were less than 50%. In general, the MODIS fine mode aerosol products were better than Himawari-8''s. However, it was still inaccuracy comparing with the AERONET observations. Therefore, it is necessary to further study the retrieval methods to improve the accuracy of the surface reflectance. By comparing the seasonal results, it was found that the derived values of MODIS and Himawari-8 were underestimated in spring, summer, autumn and winter, but the seasonal errors for MODIS fAOD were relatively small. The mean deviation of the Himawari-8 FMF in the Dhaka_University station was large in the fall. The maximum deviation for the MODIS FMF in spring and winter were relatively large, but they were relatively small in summer and autumn. The deviation of Himawari-8 fAOD was larger, and its maximum deviation was larger than the MODIS fAOD''s. Meanwhile, the annual and seasonal distribution characteristics of FMF and fAOD in Asia were analyzed by MODIS and Himawari-8 observations. It was found that the high-value areas of FMF in MODIS and Himawari-8 were mainly located in North China Plain, Northeast Plain, Sichuan Basin and Indochina Peninsula. The high-value areas of MODIS fAOD was in Indochina Peninsula, but the annual mean value of Himawari-8 fAOD was generally low in these areas. The seasonal average distribution of MODIS FMF and fAOD were high in summer and autumn and were low in spring and winter, but the Himawari-8 FMF and fAOD were high in spring and autumn and were low in summer and winter.