综合莫兰指数和交叉小波的不均匀沉降量化分析

Quantitative analysis of uneven subsidence by Moran’s I and cross wavelet

由于针对地面沉降不均匀态势的量化分析较少,采用永久散射体干涉测量(persistent scatterer inteferomotry,PSI)方法获取北京平原地面沉降信息。根据浅地表空间利用差异在沉降漏斗区选取5个典型区,基于空间自相关分析和小波分析方法,量化了各区地面沉降空间和时序不均匀程度。并研究了浅地表空间利用差异和地下水位变化对空间和时序不均匀沉降的影响。研究发现:①5个区域每年累计沉降量和时序沉降量的莫兰指数大小关系相同,均为I5>I3>I1>I2>I4,结合浅地表空间利用情况,区域3和4不均匀沉降的影响因素较复杂,区域1,2和5沉降空间不均匀程度与空间利用复杂程度呈正相关;②各区地下水流场变化的波动大小和持续时间长短直接影响区域时序沉降不均匀程度。

To address the problem that quantitative analysis of uneven subsidence is rare,the authors used the Permanent Scatterer Interferometry(PSI)to monitor land subsidence in the Beijing plain.According to the different shallow surface spatial utilizations,the authors selected 5 typical areas in the subsidence funnel region.Based on spatial autocorrelation analysis and wavelet analysis,the authors quantified the degree of spatial and annual time series uneven subsidence in each area,and studied the influence of different shallow surface spatial utilization and groundwater level variation on spatial and annual time series uneven subsidence.The results are as follows:①Annual time series subsidence’s Moran index degrees of 5 areas are the same as those of the accumulated subsidence:I5>I3>I1>I2>I4.According to the utilization of shallow surface space,the degree of uneven subsidence of 1,2,5 areas are positively correlated with the complexity of space utilization,and the factors affecting the uneven subsidence degree of area 3,4 are complicated.②It is found that the variation and duration of groundwater level fluctuation are the main factors affecting the uneven degree of time series subsidence.