Evaluation of satellite and reanalysis products of downward surface solar radiation over East Asia: Spatial and seasonal variations
Evaluation of satellite and reanalysis products of downward surface solar radiation over East Asia: Spatial and seasonal variations
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DOI：
10.1002/jgrd.50353
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发表时间：
2013-05-16
影响因子：
4.4
通讯作者：
Chen, Feng
中科院分区：
文献类型：
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作者：
Jia, Binghao;Xie, Zhenghui;Chen, Feng
地表太阳辐射在地表能量和水分收支中起着至关重要的作用，也是陆地水文模型的重要强迫。利用2006年7月至2009年6月中国大陆94个台站的地面观测资料（OBS），对风云二号C卫星（FY-2C）和快速长短波辐射通量（FLASHFlux）两个卫星产品以及NCEP-DOE和ERA-Interim两个再分析数据集的地表向下辐射（DSSR）进行了分析。结果表明，FY-2C反演的DSSR与OBS反演结果相当，日资料和月资料的正偏差分别为3.0 Wm（-2）和3.5 Wm（-2），RMSE分别为49.3 Wm（-2）和31.9 Wm（-2）。这些结果与FLASHFlux的结果相当，FLASHFlux在四种产品中具有最低的RMSE（每日和每月数据分别为43.2 Wm（-2）和30.5 Wm（-2）），并且与OBS的相关性最强（每日和每月数据分别为r=0.90和0.93）。与卫星产品相比，再分析的DSSR具有更大的RMSE，并且与OBS的相关性普遍较低，特别是对于NCEP-DOE产品。结果还表明，日DSSR值是敏感的平均网格大小，而月平均DSSR是在很大程度上不敏感的平均尺度。东亚地区四个数据集的DSSR表现出相似的空间格局，季节变化较大，但幅度不同。夏季，中国西部地区DSSR偏高，而南亚和四川盆地地区DSSR偏低，这与广泛的云量（CC）和大量的可降水量（PW）有关。在冬季，由于CC和PW的减少，DSSR的高中心转移到南亚，并且DSSR从南到北逐渐减小。云、气溶胶和水汽参数化的缺陷以及大气和地面特性反演算法的误差导致FY-2C的DSSR与OBS的相关性低于FLASHFlux产品（日和月数据的相关系数分别为0.82和0.90）。FY-2C反演算法中云和气溶胶的表示需要进一步改进。
Surface solar radiation plays a crucial role in surface energy and water budgets, and it is also an important forcing for land hydrological models. In this study, the downward surface solar radiation (DSSR) from two satellite products, the Fengyun-2C satellite (FY-2C) and the Fast Longwave and Shortwave Radiative Fluxes project (FLASHFlux), and two reanalysis datasets, NCEP-DOE and ERA-Interim, was evaluated against ground-based observations (OBS) from 94 stations over mainland China during July 2006 to June 2009. It is found that the mean DSSR derived from FY-2C is comparable to OBS, with small positive biases of 3.0 Wm(-2) for daily data and 3.5 Wm(-2) for monthly data and moderate RMSEs of 49.3 Wm(-2) (daily) and 31.9 Wm(-2) (monthly). These results are comparable to those for FLASHFlux, which has the lowest RMSEs (43.2 Wm(-2) and 30.5 Wm(-2) for daily and monthly data, respectively) and the strongest correlations with OBS (r=0.90 and 0.93 for daily and monthly data, respectively) among the four products. The DSSR from the reanalyses has much larger RMSEs and generally lower correlations with OBS than the satellite products, especially for the NCEP-DOE products. Results also show that daily DSSR values are sensitive to the averaging grid size, while monthly mean DSSR is largely insensitive to the averaging scale. The DSSR from the four datasets over East Asia shows similar spatial patterns with large seasonal variations but differs in magnitude. In summer, high DSSR is observed over western China, while low DSSR is seen primarily over South Asia and the Sichuan Basin associated with extensive cloud cover (CC) and large precipitable water (PW). In winter, the high DSSR center shifts to South Asia due to decreased CC and PW, and the DSSR decreases from the South to the North. Deficiencies in the parameterizations of clouds, aerosols, and water vapor, as well as errors in atmospheric and surface properties for the retrieval algorithms contribute to the lower correlation of the DSSR derived from FY-2C (r=0.82 and 0.90 for daily and monthly data) with OBS than those from FLASHFlux product. Further improvements to the representation of clouds and aerosols in the FY-2C retrieval algorithm are needed.