针对长时间序列土壤湿度数据集在国内缺乏验证的问题,利用中国区19912013年实测土壤湿度数据,使用广泛应用于土壤湿度遥感产品的验证方法TC(triple collocation),对欧空局气候变化倡议项目(climate change initiative,CCI)土壤湿度数据集(ESA CCI SM)合成前的主、被动微波数据产品在中国区的精度进行评估比较。结果表明,从各项统计指标来看,主动微波产品的表现均好于被动微波产品;尽管ESA CCI SM融合后产品精度高于融合前,但在具体应用中,应当根据主、被动微波特性选择使用。研究结果有助于更深刻地理解该产品的误差结构与融合过程中的误差传递特性,从而更好地将其应用于气候分析、水文预报等领域。
英文摘要:
The merged global soil moisture product,the European Space Agency Climate Change Initiative Soil Moisture Product(ESA CCI SM),is the first purely multi-decadal satellite-based soil moisture product spanning from 1978to 2013. Validation of this product is a critical aspect before using it.This study contributes to the comparative evaluation of ESA CCI SM active and passive microwave soil moisture products in China from 1991to 2013using Triple Collocation(TC),a method widely used in the validation of remotely sensed soil moisture products.The result indicates that,in terms of all of the statistics,the active microwave soil moisture product performs better than the passive one.Although the merged dataset performs better than the products before merging,in practice,one should select and use an appropriate product according to the characteristics of active and passive microwave products.This study furthers the understandings of the error structure in ESA CCI SM,and thus this product can be used optimally in climatological analysis and hydrological forecasting.