Remote Sensing Retrieval Of Summer Land Surface Temperature In The Source Region Of The Yellow River

LST(land surface temperature)can not only indicate the temperature and humidity of some areas,but also can be used for seismic monitoring through thermal infrared anomaly.In recent years,land surface temperature has been widely used in the study of ecological environment monitoring.Many scholars have done the correlation research between land surface temperature and climate change,vegetation change and so on.The source of the Yellow River in Qinghai Province is an important barrier for the ecological security of the Qinghai Tibetan Plateau.Its own ecological environment is very fragile.Under the background of global warming and increasing human activities in the source area of the Yellow River,the ecological environment of the source area has been deteriorated.The permafrost in the source region of the Yellow River has been degraded in a large area and is becoming more and more serious.The vegetation coverage in some areas is gradually reduced,the glacier area is decreasing,the lake water level is decreasing,the source water volume is decreasing year by year,the grassland is degenerating,and the soil erosion is serious.It is of great significance to study the temporal and spatial variation of surface temperature and its influencing factors in the source area of the Yellow River for regional economic development and water resources security.This paper selects high spatial resolution Landsat data,and uses a variety of single channel inversion methods(Qin Zhihao single window algorithm,universal single channel algorithm,atmospheric correction method)to invert the surface temperature of a single image in the source area of the Yellow River in summer.Through quantitative analysis of the three inversion results,the Qin Zhihao single window algorithm suitable for the whole source area of the Yellow River is finally selected,The land surface temperature in summer(July / August)from 1990 to 2018(with an interval of five years)was retrieved.The main research results are as follows: 1.The correlation coefficient between the retrieved summer mean land surface temperature and MODIS land surface temperature in the source region of the Yellow River is medium,about 0.5,mainly because of the inconsistency of spatial resolution between Landsat and MODIS;The inversion data are inlaid with images of different time phases;A little amount of cloud obscured the surface of the earth.2.Extracting the surface temperature of different types of surface features from the retrieved surface temperature values,the surface temperature of water body basically remains unchanged,the surface temperature of other surface features show an upward trend,and the surface temperature of glacier increases the fastest.3.Elevation has the most direct effect on the surface temperature.It is found that there is a significant negative correlation between the surface temperature and elevation in the source area of the Yellow River in each year,and the average correlation coefficient is-0.65.4.Spatially,there is a negative correlation between surface temperature and soil moisture.5.Among the climatic factors,there is a negative correlation between precipitation and land surface temperature,and 70% of the pixels with correlation coefficient less than-0.5;Temperature also has a certain influence on the change of surface temperature in summer in the source region of the Yellow River.6.There is a positive correlation between sunshine hours and land surface temperature in nearly 65% of the study area.