基于CCI数据的中国北方地区土壤水分时空变化特征分析

针对我国实测土壤水分站点稀疏、分布不均、数据连续性较差且在大尺度鲜有研究的问题，将欧洲空间局气候变化项目（European Space Agency climate change initiative, ESA CCI）的土壤湿度数据集应用于中国北方5大农业生态区，开展土壤水分时空变化分析. 采用皮尔逊相关系数进行遥感数据的有效性验证，利用时空持久性概念分析土壤水分的时空变化规律. 结果表明:ESA CCI遥感土壤水分数据在东北区夏季、西北区春季、黄土高原区春夏秋季、内蒙古高原区夏秋季具有很好的时空适应性；北方地区1991—2016年间土壤体积含水量年均值为0.06~0.39 m3·m?3，空间分布呈现出由西向东土壤水分逐渐升高的趋势，并表现出夏季最高、秋季其次、冬春季较低的季节特征；东北区、黄土高原区、黄淮海区中我国的重要粮食产区的土壤水分呈现出随时间季节变化波动大，且有较为明显的变干趋势. 

Temporal and spatial variations in soil moisture in Northern China as demonstrated by CCI data

Due to sparse, uneven data distribution, poor data continuity, poor large scale-research, soil moisture data of European Space Agency Climate Change Initiative (ESA CCI) was applied to five agro-ecological zones in Northern China. Pearson correlation coefficient was used to validate remote sensing data, spatio-temporal persistence was used to analyze spatial-temporal variations in soil moisture. ESA CCI remote-sensing soil-moisture data set was found to have good spatial and temporal adaptability to Northeast China in summer, in Northwest China in spring, in Loess Plateau in spring and summer, and in Inner Mongolia Plateau in summer and autumn. The annual average soil moisture in Northern China from 1991-2016 was found to be 0.06-0.39 m3?m?3. Gradual increase in soil water content was found from west to east, with the highest values in summer. Lower seasonal values were found in autumn, winter and spring. Important grain production areas in the Northeast, Loess Plateau and Huang-Huai-Hai region demonstrated great fluctuations with time and season, a tendency to dry out was also revealed.