The Method for Retrieving Downward Atmospheric Long-wave Radiation Using Remotely Sensing Technique

Using the measured data acquired from the experiments of the agriculture demonstration field in Xiaotangshan, Beijing in 2004 by automatic weather stations and thermal infrared thermometers, the correlation expression was established between surface radiometric temperature T at the time of Landsat /TM passing by the study area and air temperature T₀. Through analyzing the data from 21 regular weather stations in Beijing and 5 scenes TM images in 2004, Beijing, the experience expression between the thermal inertia (P) and air vapor pressure (e₀) was created. Furthermore, the model of Izionmon(2003) was used based on the two expressions, and the spatial model was given that retrieve the pixel downward atmospheric radiation under clear day using the remote sensing parameters, such as thermal inertia and surface net radiation fluxes. The retrieve results were validated using experiment measuring data in practice. The improvement on the precision rather than 9.5% of estimating the surface net radiation fluxes by using the calculated downward atmospheric radiation on the pixel basis. It shows that is feasible to estimate the downward atmospheric radiation by making use of the thermal inertia and the surface radiometric temperature.