基于最小响应单元的地下水埋深时空分异特征研究

Spatial and Temporal Variation Characteristics of Groundwater Depth Based on Minimum Response Unit

采用协同克里金插值方法,以2005、2009、2013、2017年4 a翁牛特旗地下水埋深为主变量,以NDVI(归一化植被指数)、降水量和河网密度为协变量,计算研究区内的地下水埋深,运用改进水文响应单元模式,在空间上将协同克里金插值后的地下水埋深栅格数据转换为矢量数据,将传统的简单插值分析方法运用协同克里金和最小响应单元进行改进,使之更贴合实际地下水汇流情况,获取最小响应单元551个,并据此进行空间整体与局部自相关分析。结果表明,在研究区空间上,地下水埋深东西分异规律明显,地下水位呈现西高、东低的态势,受降水和河流影响逐渐变大;在时间序列上,地下水埋深平均变化不大,但逐渐呈现聚集的趋势。

Based on co-Kriging interpolation,the normalized vegetation index(NDVI),precipitation and river network density were used as covariates,and the groundwater depth of the Wengniute Banner in four phases of 2005—2017 was taken as the main variable.Then the groundwater depth in the study area was calculated.Using the improved hydrological response unit mode,the interpolated groundwater depth was spatially converted into vector data.And the traditional simple interpolation result analysis method was improved by using co-Kriging and minimum response unit to make it more suitable for actual groundwater convergence,and 551 minimum response units were obtained.Based on this,spatial and local autocorrelation analysis was performed.It can be observed that the depth of groundwater was obviously different spatially.The groundwater level was high in the west and low in the east,which was gradually affected by precipitation and rivers.The average depth of groundwater in time series did not change much,but it gradually showed a tendency of aggregation.