MPI （microwave polarization index） method can use different frequencies at vertical polarization to retrieve soil moisture from TMI （tropical microwave imager） data, which is mainly suitable for bare soil. This pa...MPI （microwave polarization index） method can use different frequencies at vertical polarization to retrieve soil moisture from TMI （tropical microwave imager） data, which is mainly suitable for bare soil. This paper makes an improvement for MPI method which makes it suitable for surface covered by vegetation. The MPI by using single frequency at different polarizations is used to discriminate the bare soil and vegetation which overcomes the difficulty in previous algorithms by using optical remote sensing data, and then the revision is made according to the different land surface types. The validation by using ground measurement data indicates that revision for different land surface types can improve the retrieval accuracy. The average error is about 24.5% by using the ground truth data obtained from ground observation stations, and the retrieval error is about 13.7% after making a revision by using ground measurement data from local observation stations for different surface types. The improved MPI method and precipitation are used to analyze the drought in Southwest China, and the analysis indicates the soil moisture retrieved by improved MPI method can be used to monitor the drought.展开更多
土壤水分是监测作物旱情的基本因子,以欧空局1978~2014年微波遥感土壤水分产品、中国经济与社会发展统计数据库以及气象数据为基础,结合土壤水分亏缺指数(Soil Water Deficit Index,SWDI)分析东北地区的干旱程度与玉米亩产的关系。结果...土壤水分是监测作物旱情的基本因子,以欧空局1978~2014年微波遥感土壤水分产品、中国经济与社会发展统计数据库以及气象数据为基础,结合土壤水分亏缺指数(Soil Water Deficit Index,SWDI)分析东北地区的干旱程度与玉米亩产的关系。结果表明:①东北三省干旱程度空间上呈现自东北向西南逐渐加重的空间分布模式;②基于CCI(Climate Change Initiative)土壤水分产品计算的SWDI干旱指数与降雨量和气温有良好的相关关系,可用于评估干旱发生的严重程度;③玉米生长季关键需水期——7月的SWDI与玉米产量的相关性最好,二者在黑龙江、吉林和辽宁省的R2分别为0.43、0.78和0.38,非常适合用于评估干旱对玉米单产的影响。该结论对于研究大范围土壤水分含量对农作物产量的影响以及相关农业决策具有重要指导意义。展开更多
基金supported by the National Basic Research Program of China (2010CB951503)the National Natural Science Foundation of China(40930101)+2 种基金the Open Fund of the State Key Laboratory of Remote Sensing Sciencejointly sponsored by the Institute of Remote Sensing Applications of the Chinese Academy of Sciences and Beijing Normal University, Chinathe Open Fund of Key Laboratory of Agrometeorological Safeguard and Applied, China Meteorological Administration
文摘MPI （microwave polarization index） method can use different frequencies at vertical polarization to retrieve soil moisture from TMI （tropical microwave imager） data, which is mainly suitable for bare soil. This paper makes an improvement for MPI method which makes it suitable for surface covered by vegetation. The MPI by using single frequency at different polarizations is used to discriminate the bare soil and vegetation which overcomes the difficulty in previous algorithms by using optical remote sensing data, and then the revision is made according to the different land surface types. The validation by using ground measurement data indicates that revision for different land surface types can improve the retrieval accuracy. The average error is about 24.5% by using the ground truth data obtained from ground observation stations, and the retrieval error is about 13.7% after making a revision by using ground measurement data from local observation stations for different surface types. The improved MPI method and precipitation are used to analyze the drought in Southwest China, and the analysis indicates the soil moisture retrieved by improved MPI method can be used to monitor the drought.
