青藏高原土壤水分时空变化特征及其与气候变化的关系研究

Spatiotemporal Variation Characteristics of Soil Moisture and its Relationship with Climate Change on the Qinghai-Tibet Plateau

利用SMAP反演的土壤水分和ERA5再分析格点数据,采用趋势斜率法和相关性分析法,分析了青藏高原春季土壤水分时空变化特征及其与夏季气温和降水量的相关性。结果表明:青藏高原春季土壤水分呈微弱的减少趋势,空间上呈由西向东逐步增大的分布特征,近17 a土壤水分增加区域面积占高原总面积的42.37%,增加区域主要位于西藏阿里、日喀则大部、那曲中部、林芝西北部,以及青海大部;减少区域则位于四川大部、新疆大部、西藏山南和昌都。青藏高原春季土壤水分与夏季降水量和气温间具有较好的相关性,其中夏季气温与土壤水分呈正相关的区域占总面积的8.56%,正相关区域主要集中在高原北部柴达木盆地和日喀则中部区域,负相关区域位于高原大部,主要在西藏藏北、藏南和中部地区,以及四川和青海省大部。降水与土壤水分呈正相关的区域占总面积的41.69%。正相关区域在藏北阿里、那曲北部和林芝大部区域,负相关区域位于日喀则、拉萨、山南中部、昌都、和那曲东南部。

Based on the soil moisture retrieved by SMAP and reanalyzed the grid data by ERA5,the spatiotempo-ral characteristics of spring soil moisture changes and its correlation with summer temperature and precipitation in the Qinghai-Tibet Plateau were analyzed by using trend slope method and correlation analysis method.The spring soil moisture of the Qinghai-Tibet Plateau showed a weak decreasing trend with a spatial distribution characteristic of gradual increasing from west to east.The area of increased soil moisture in the past 17 years ac-counted for 42.37%of total area of the plateau and the increased soil moisture areas are mainly located in Ali,most part of Xigaze,central Naqu,northwest part of Linzhi in Tibet and the most part of Qinghai.The areas of re-duced soil moisture are located in the most part of Sichuan,the most part of Xinjiang,Shannan and Qamdo in Ti-bet.There is a certain correlation between spring soil moisture with summer precipitation and temperature on the Qinghai-Tibet Plateau with the areas where summer temperature and soil moisture are positively correlated ac-counting for 8.56%of the total area and are mainly concentrated in the Qaidam Basin in the northern part of pla-teau and the central Xigaze.The areas with a negative correlation between spring soil moisture and summer pre-cipitation and temperature are located in the most part of the plateau including northern,southern,and central parts of Tibet as well as the most part of Sichuan and Qinghai provinces.The area with precipitation and soil moisture are positively correlated accounted for 41.69%of the total area and the positivecorrelated areas are lo-cated in the Ali of the northern part of Tibet,the northern part of Nagqu and the most part of Linzhi,while the negative correlated areas are located in the Xigaze,Lhasa,central Shannan,Qamdo,and the southeast part of Nagqu.