Analysis of downwelling surface solar radiation in China from National Centers for Environmental Prediction reanalysis, satellite estimates, and surface observations
Analysis of downwelling surface solar radiation in China from National Centers for Environmental Prediction reanalysis, satellite estimates, and surface observations
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DOI：
10.1029/2005jd006405
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发表时间：
2006-05
影响因子：
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通讯作者：
X. Xia;Pucai C. Wang;H. Chen;F. Liang
中科院分区：
文献类型：
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作者：
X. Xia;Pucai C. Wang;H. Chen;F. Liang
[1]利用4个太阳辐射观测资料，分析了我国地表太阳辐射的分布特征。美国国家环境预测中心（NCEP）再分析的太阳辐射数据比地面观测值高出40 W/m2，超过100 W/m2。由戈达德空间研究所（GISS）和马里兰州大学（UMD）提供的卫星数据集与地面观测数据有显著的相关性，但在中国大部分地区，卫星估计值超过了地面观测值。最大的差异发生在长江中游和沿海地区，卫星算法偶尔会高估太阳辐射超过40 W/m2。在区域尺度上，卫星估算的平均偏差范围为约8 W/m2至约36 W/m2。均方根误差在约20至36 W/m2之间变化。卫星数据和地面数据之间的时空抽样差异的影响可能是造成卫星估计数随机不确定性的部分原因。中国卫星算法的系统性高估很可能与气溶胶及其与云的复杂相互作用有关。地面数据表明，从1961年到1990年，太阳辐射量大幅度下降，但下降趋势没有持续到1990年代。相反，从1984年到2000年，出现了明显的增长趋势，每十年增长1.7%至7.7%。由于同期云量显著减少，预计不会减少，但这与能见度下降所显示的气溶胶含量增加一致。NCEP的数据和卫星估计表明，太阳辐射的趋势截然不同。利用1961~2000年NCEP资料，分析了除华南外的三个区域的边际增长趋势。自1980年代中期以来，从卫星估计得出的趋势远低于地面观测得出的趋势。此外，这两个卫星估计显示，从1984年到2000年，中国大部分地区都有下降趋势。这些差异表明，气溶胶和云的代表性应加以改进，以使卫星估计更可靠的高气溶胶负载的地区。
[1] Solar radiation reaching the surface in China was analyzed on the basis of four data sets. National Centers for Environment Prediction (NCEP) reanalysis solar radiation data exceeded surface observations by 40 W/m2 to more than 100 W/m2. Satellite data sets produced by Goddard Institute for Space Studies (GISS) and University of Maryland (UMD) were correlated significantly with surface observations, but satellite estimates exceeded surface observations over much of China. The largest difference occurred in the middle reach of Yangze river and coast regions where satellite algorithms occasionally overestimated solar radiation by more than 40 W/m2. The mean bias of satellite estimates ranged from about 8 W/m2 to about 36 W/m2 in regional scale. The root-mean-square error varied from about 20 to 36 W/m2. The effects of differences in space-time sampling between satellite and surface data might account partly for the random uncertainties of satellite estimates. The systematic overestimation by satellite algorithms in China was most likely associated with aerosols and their complex interactions with clouds. Surface data indicated a significant decline in solar radiation from 1961 to 1990, but the decline trend did not persist into the 1990s. Instead, a pronounced increase trend has been observed from 1984 to 2000, ranging from 1.7% to 7.7% per decade. The decrease would not be expected given that the cloud amount decreased significantly during the same period, but this was in accordance with the increasing aerosol loading that was indicated by the visibility deterioration. NCEP data and satellite estimates indicated quite different trends in solar radiation. The marginal increase trends were derived on the basis of NCEP data from 1961 to 2000 in three regions except in south China. The trends derived from satellite estimates since the middle 1980s were much less than that of surface observations. Moreover, both satellite estimates showed decline trends over much of China from 1984 to 2000. These differences suggested that representation of aerosols and clouds should be improved in order to make satellite estimates more robust over regions with high aerosol loading.