基于干旱/半干旱区协同观测网络的GLASS下行短波辐射产品精度验证及影响因素评估
Validation for Downward Shortwave Radiation of GLASS Product by the Coordinated Enhanced Observation
中文摘要：
下行短波辐射（Downward Shortwave Radiation，DSR）是地表接收太阳辐射的重要组成部分，是地表能量平衡和地气相互作用的重要驱动因素，同时DSR的变化影响着天气过程与气候变化。遥感手段获取的DSR产品已成为陆面过程与气候变化研究的重要驱动参数，对DSR数据的验证与评估能为相关研究提供必要的数据精度与可靠性信息，同时反馈于相关数据产品的改进工作。使用干旱/半干旱区协同观测网络为研究评估数据源，对新一代DSR产品（Global LandSurface Parameters-Downward Shortwave Radiation，GLASS-DSR）进行验证评估，发现在中国北方干旱/半干旱区该数据与观测具有较好的一致性，整体相对误差小于4%，RMSE小于140W·m－2。在不同站点评估效果有一定程度差异，均一下垫面具有较好效果。研究也发现卫星观测辐射的精度受到时空尺度的影响，卫星获取DSR存在明显的观测特征尺度。
中文关键词：
下行短波辐射，干旱/半干旱区，辐射收支
KeyWords：
downward shortwave radiation, arid/semi-arid area, radiation budget
Abstract：
As a driving force of the surface energy balance and the land-atmosphere interaction, downward shortwave radiation (DSR) is an important component solar radiation received in the land surface, which has already affected weather processes and climate change. Currently, DSR obtained by means of remote sensing products has become key parameters for land surface processes and climate change research, and validation for DSR datasets will provide necessary or reliability information of DSR datasets by errors evaluation, further improving next-generation DSR datasets. In this study, surface shortwave albedo of each station were derived from field measurements of the Coordinated Enhanced Observation Network to assess the new generation DSR product of Global Land Surface Parameters- Downward Shortwave Radiation, GLASS-DSR and evaluate its reliability. Good agreements were found between the field measurement and satellite results with overall relative errors fewer than 4% and RMSE fewer than 140 W·m－2. It is heterogeneous among different observation sites, and better agreements were homogenously achieved. The characteristic scale was also found for monitoring downward shortwave radiation variation, which is an important factor in influencing the accuracy of derived DSR.