| Region surface energy change features can reflect the evolution trend in Land-atmosphere processes, influencing the regional climatic change. Facilitated by the mature remote sensing technology, studying regional surface energy in large scale can be convenient and fast. The study on surface energy flux of Qinling mountain areas will enable the study on the climate change due to the land cover change around Qinling. Therefore, moniter and study the surface energy of Qinling area with remote sense method possesses significant sense and research value.In this study, surface energy flux was inverted using MODIS, DEM and meteorological data based on the surface energy flux inversion model realized by the IDL and Arcpy. After analyzing and discussing the inversion result, the main conclusions were obtained as follows:1. The average albedo rate of the study area in 2000,2005,2010 and 2015 were 0.32,0.11, 0.48 and 0.16, respectively; the surface temperature were 266.00 K, 275.07 K,251.97 K and 263.14 K, respectively; the Surface Emissivity were 0.86, 0.93,0.87,0.91.2. The average net radiation in 2000, 2005, 2010 and 2015 were715.21 W·m-2, 798.15 W·m-2, 602.76 W·m-2 and 804.75 W·m-2, respectively; the average soil heat flux were-63.30 W·m-2, 4.63 W·m-2,-100.06 W·m-2 and-37.39 W·m-2, respectively; the average latent heat flux were 722.26 W·m-2, 735.98 W·m-2, 654.75 W·m-2 and 780.47 W·m-2, respectively.3. The net radiation increased 8.5% in the slope of 0~5 degrees between 2000 and 2015; 8.0% in the slope of 5~10 degrees; 9.0% in the slope of 10~15 degrees; 10.1% in the slope of 15~20 degrees; 12% in the slope of 20~28 degrees; 14% in the slope of 28~85.62 degrees. The variation of net radiation followed Trigonometric function change as the slope increased, achieving the minimum when the slope is between 30 degrees and 60 degrees, and the maximum when the slope is between 180 degrees and 210 degrees. The net radiation during 2000 and 2015 decreased when the ground surface temperature is between 255 K and 260K; stay steady between 250 K and 255K; and showed a trend of increasing first and then decreasing, however the increasing range was much higher than decreasing range.4. The soil heat flux in 2000, 2005 and 2010 decreased with the increase of slope by 13.4%, 80% and 18.8%, respectively; the soil heat flux changed little as the soil increased in 2015. The soil heat flux change followed the quadratic curve as the slope increased, achieved the maximum when the slope is between 210 degrees to 240 degrees, the minimum between 330 degrees and 360 degrees. The soil heat flux increased as the ground surface temperature increased in 2000, 2005, 2010 and 2015, though, stayed stable in the same temperature interval from 2000 to 2015.5. the latent heat flux decreased with the slope increased in 2000, the reduction rate was 3%; In 2005,2010 and 2015, the latent heat flux showed a increase trend, the growth rate was 4.4%, 3.4% and 1.8%, respectively. The soil heat flux showed a sine curve with the increase of slope direction, achieved the maximum when the slope is between 30 degrees and 90 degrees, the minimum between 180 degrees and 240 degrees. The lantent heat flux in 2000, 2005, 2010 and 2015 showed a decrease trend with the increase of ground surface temperature, the reduction rates were 0.88%,5.00%,25.36% and 9.34%, respectively.6. As to the influence of net radiation, albedo>ground surface temperture>surface emissivity; as to the soil heat flux, ground surface temperature>albedo>surface emissivity; as to the influence of latent heat flux, abledo>ground surface temperature>surface emissivity. |
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