基于Landsat数据的开都河两岸绿洲地下水遥感监测及影响因素分析

Landsat data based monitoring of groundwater depth and its influencing factors in oasis area of Kaidu River both sides

为了研究干旱区绿洲地下水位时空变化特征及其归因,以新疆开都河两岸绿洲为研究对象,利用实测地下水埋深数据和Landsat数据计算得到的改进型温度植被干旱指数(MTVDI)相结合,建立了地下水位监测关系模型(R2=0.82)。对研究区1999年到2016年地下水的时空分布进行了监测,利用2005年和2003年两年实测数据对模型进行了验证。结果表明:1)两年实测地下水位和监测水位相关系数(R2)分别为0.75和0.77,均方根误差(RMSE)分别为0.17和0.27,平均相对误差(RME)分别为11.4%和16.7%,研究结果符合研究区实际情况;利用MTVDI建立的地下水位监测模型对干旱区绿洲一定深度的地下水位监测是可行的;2)开都河两岸绿洲1999年到2016年地下水位年际变化逐渐降低,年内地下水位升降显著;3)地下水位年际降低的主要原因是耕地面积的增加和灌溉方式向高效节水方式转变,增加了地下水开采量和降低了补给量。在年内随着渠系灌溉水的作用,使地下水位在季节性里变化较大。

In order to research the spatial and temporal variation characteristics of groundwater depth and its influencing factors,groundwater depth retrieving model（ the correlation coefficient of retrieved and observed data is about0. 82） is established by using MTVDI and field observation data from Landsat remotely sensed data in oasis area of Kaidu river both sides,Xinjiang. The spatio-temporal variation of groundwater depth is monitored from 1999 to2016,and monitoring results is validated by observed groundwater depth data in 2003 and 2005. Results demonstrate that： 1） The correlation coefficient between observed and monitored groundwater depth in two years are 0. 75 and 0. 77,corresponding RMSE are 0. 17 and 0. 27,RME are 11. 4 and 16. 7 respectively. Monitored results accord with actual situation,and the groundwater depth retrieving model established by using MTVDI is practical for monitoring the groundwater depth in a certain extent in the oasis of arid land area. 2） The groundwater depth de-creased from 1999 to 2016,and the annual variation is notable. 3） The main causes of inter-annual variations and decrease of groundwater depth are increased the agricultural area and modern irrigation system which resulted in large amount of groundwater exploitation and declining groundwater supply. The annual variation of Kaidu river runoff and infiltration of irrigation canals effect annual variation of groundwater depth,and increase the seasonal change of groundwater depth.