Construction of soil moisture monitoring model in desertification open-pit mining area :taking Hongshaquan Mining Area as an example

Soil moisture is an important indicator that characterizes the surface environment of mining areas. Accurate monitoring of soil moisture in desertified open-pit mines plays a key role in ecological protection and sustainable development of mining areas. Taking the typical desertification open-pit mining area-Zhundong Hongshaquan Mining Area and surrounding areas as the research object,based on Landsat 8 OLI image,the normalized vegetation index (NDVI),the ratio vegetation index (RVI),the vegetation conditional index (VCI),the apparent thermal inertia (ATI) and the Conditional Temperature Index (TCI) based on the thermal infrared band,the perpendicular drought index (PDI) based on the reflectance characteristic space and the soil moisture monitoring index (SMMI) based on the vegetation information were used to retrieve the soil moisture in desertification mining areas. The inversion results are not consistent with the soil moisture of the measured sample points,that is,the traditional soil moisture index cannot be used as an exponential factor of the soil moisture in the study area alone. In view of the shortcomings of the above indexes and the special ecological environment of the study area,the new bare rock gravel index NGLI is proposed,and combined with SMMI,NGLI and NDVI,a soil moisture model NMSMI,was constructed to evaluate its accuracy and applicability,and finally evaluate its accuracy and applicability. The results show that: ① The constructed NGLI (new gravel land index,NGLI) can effectively extract the soil moisture of bare gravel land and the open pit in the study area,and the NGLI is negatively correlated with the measured soil moisture (R2=0.245,P<0.01),the root mean square error RMSE of the verification point is 0.009; ② Based on the linear weighting method,a new modified soil moisture index (NMSMI) was constructed by using SMMI,NDVI,and NGLI. It was verified that the index was negatively correlated with the measured soil moisture (R2=0.517,P<0.01),the root mean square error RMSE of the verification point is 0.004,and the inversion results were consistent with the measured soil moisture in spatial distribution. By comparing and verifying the measured data with the traditional indexes and NMSMI index,it is shown that NMSMI index is suitable for soil moisture monitoring in special desertification open-pit mining areas.