Spatial And Temporal Variation Of Soil Moisture In The Babao River Basin In The Upper Heihe River Basin Based On An Improved Thermal Inertia Model

Soil moisture is an important factor in the ecological process of the earth,and it is an essential element of life activities.It plays an important role in the stability of the global environment.The real-time and accurate inversion of soil water content data can play a major role in the prediction of drought and the understanding of regional water cycle mechanisms.The Heihe River Basin is located in the central part of the Eurasian continent,far from the sea and surrounded by the surrounding mountains.Affected by the continental climate and the Qilian-Qinghai Lake climate zone of the Qinghai-Tibet Plateau,the Heihe River Basin is in a typical arid and semi-arid region.The population of the Heihe River Basin is sparse and the coverage of vegetation is low,which is of great value in studying the law of soil moisture changes under natural conditions.Based on the improved thermal inertia model,this paper uses the landsat satellite Landsat TM/OLI remote sensing image of the United States NASA as the basic data and be assisted by hourly surface air temperature and other data.This paper inverts the soil moisture content of the Babao River Basin in the upper reaches of the Heihe River from 1986 to 2015,and uses the measured data to verify the accuracy of the study area.The main research results of the paper are as follows:The improved thermal inertia model based on Landsat TM/OLI visible light remote sensing imagery is mature and available.In this experiment,the soil moisture content was retrieved from the Babao River basin in the upper reaches of the Heihe River.The average accuracy of the obtained data was about 76.04%,and the correlation was R?0.879.This method can be used as an effective way to monitor the soil water content in real time for a long time in similar areas.In terms of spatial distribution,the overall spatial variation of soil moisture in the Babao River Basin in the upper reaches of the Heihe River during 1986 to 2015 showed that the relatively high soil moisture content was concentrated from the southeast mountains along the south side of the mountain to the confluence of the northwest plains.In terms of seasons,the seasonal average soil moisture content in the Babao River Basin remains unchanged from the southeastern mountainous regions in the southeast to the northwestern lower plains along the southern mountain ranges.In terms of monthly observations,the high summer soil moisture content in the Babao River Basin is in the southeastern part of the mountainous area,and the area gradually turns to the lower reaches of the lower reaches of the Babao River in the western region from autumn to winter.In terms of time,the soil moisture content in the Babao River basin area in the upper reaches of the Heihe River is generally in an increasing stage,and the increase in the surface soil moisture content is in the central valley,and the soil moisture content around the mountains surrounding the Babao River Basin has decreased significantly.In terms of seasons,the concentration of soil moisture in the Babao River Basin in spring is in a slightly increasing trend.There is a trend of decreasing soil moisture content in mountainous areas with extremely high altitudes.The distribution of summer soil moisture changes is similar to that of spring,but the growth trend in the region is obvious.In a slowdown,the slope value of large areas was reduced visually;in the autumn,the variation of soil moisture content in the Babao River Basin was different.In addition to the higher elevations in the mountains,soil water content decreased in the prominent areas of the upper reaches of the Babao River in the east.Trend;The average plot of winter soil moisture content is in an upward trend,the trend is greater than in other seasons,and the central plain has a relatively larger increase in soil moisture content than the surrounding mountainous regions.The wind speed has a low negative correlation with the soil moisture in the Babao River basin in the upper reaches of the Heihe River.The wind speed will cause a slight disturbance to the shallow soil water content to a limited extent;the temperature has a highly positive correlation with the soil moisture in the Babao River basin in the upper reaches of the Heihe River.The relationship between temperature and temperature will directly affect the ratio of soil moisture in the Babao River Basin.The relative humidity of the air will have a negligible impact on the soil moisture content in the Babao River Basin.The influence of precipitation on the soil moisture content is still limited.Its relevance is not high.The paper is innovative in the following areas: 1.The use of Ladnsat remote sensing images as the basic data for the retrieval of regional soil moisture content improves the accuracy of soil moisture retrieval and provides a new method for the study of soil moisture at a finer scale.2.Verification of the availability of the improved thermal inertia model in the Babao River basin in the upper Heihe River.3.Spatial-temporal analysis of remote sensing inversion products using soil moisture content of 30 meters,compared with previous studies,the analysis results were obtained in a more subtle scale,and the perspective of soil moisture research was expanded.