长三角区域表层土壤水分时间稳定性及其影响因子  

Temporal Stability of Surface Soil Moisture and Its Influencing Factors in Yangtze River Delta Region

作　　者：殷贝妮 朱青[2,3] 廖凯华 YIN Beini;ZHU Qing;LIAO Kaihua(School of Geographical Sciences,Nanjing University of Information Science and Technology,Nanjing 210044,China;Key Laboratory of Watershed Geographic Sciences,Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences,Nanjing 211135,China;College of Nanjing,University of Chinese Academy of Sciences,Nanjing 211135,China)

机构地区：[1]南京信息工程大学地理科学学院,南京210044 [2]中国科学院南京地理与湖泊研究所,中国科学院流域地理学重点实验室,南京211135 [3]中国科学院大学南京学院,南京211135

出　　处：《土壤》2024年第6期1358-1370,共13页Soils

基　　金：国家杰出青年科学基金项目(42125103);中国科学院A类战略性先导科技专项(XDA23020200)资助。

摘　　要：利用长三角地区2015年4月至2018年12月逐日表层土壤水分遥感产品(1 km空间分辨率),计算各像元土壤水分的平均相对差(MRD)及其标准差(SDRD),刻画了研究区土壤水分时间稳定性;并在此基础上,采用随机森林模型探究了地形、气候和人类活动等环境因子对土壤水分时间稳定性时空分异的影响。结果表明:①年际变化上,研究区土壤水分MRD值空间变化由南向北逐渐递减,SDRD值空间分布则相反;②年内季节变化上,研究区土壤水分MRD值空间变化显著,春冬季相较于夏秋季MRD值波动更加剧烈,而SDRD值则空间变化不明显,中高值区分布各异;③研究区土壤水分MRD值空间分布和高程、坡度以及降水分布大致相同,土壤水分MRD值随这3个环境因子的升高而呈现增高的趋势,SDRD值分布则与其相反,其余环境因子在空间分布上对土壤水分时间稳定性有影响;④气候因子和地形因子对研究区土壤水分时间稳定性贡献率最高,其余环境因子在不同的季节和土壤覆被类型上影响程度不同。In this study,the daily remote sensing data of surface soil moisture with 1 km spatial resolution in the Yangtze River Delta region from April 2015 to December 2018 were analyzed,the temporal stability of soil moisture was assessed by the mean relative difference(MRD)and its standard deviation(SDRD)for each pixel of the data,and random forest model was employed to explore the impact of environmental factors like topography,climate,and human activities on the temporal differentiation and stability soil moisture.The results showed that:1)In terms of interannual variation,MRD of soil moisture in study area exhibited a gradual decrease in spatial variation from north to south,while SDRD showed the opposite trend.2)In terms of seasonal change within a year,the spatial variation of soil moisture MRD was more significant.The fluctuation was more pronounced in spring and winter compared to summer and fall.And the spatial variation of SDRD was less distinct,and the distribution of middle-and high-value zones differed.3)The spatial distribution of soil moisture MRD was closely correlated with elevation,slope and precipitation.As MRD increased,these factors also showed a tendency to increase.However,the distribution of SDRD exhibited an opposite trend,while other environmental factors affected its spatial distribution.4)Climate and topography factors exhibited the highest contribution to time stability of soil moisture in study area,and other environmental factors had varying degrees of influence depending on the season and soil cover type.

关 键 词：土壤水文 时间稳定性 环境因子 时空分异 

分 类 号：S152.7[农业科学—土壤学]