沙尘识别是沙尘灾害监测和沙尘气溶胶特性研究的首要工作。利用辐射传输方程进行了沙尘气溶胶的辐射计算 ,对不同沙尘气溶胶光学厚度下的热红外通道温差ΔT(T11μm-T12 μm)的变化进行了分析。理论分析表明 ,利用热红外通道的温度差ΔT进行陆地沙尘识别是可行的。并利用NOAA AVHRR热红外通道的温度差ΔT进行了陆地沙尘识别的实验 ,经与地面气象站实测的沙尘天气现象相比较 ,结果一致。

Aerosol is a key factor to understand uncertainties in the study of atomsohere radiation equilibrium and climate change,and Asia dust is an impertant source of aerosol.In addition,dust detection is the first step to monitor dust disaster and study dust aerosol.Some detection methods using brightness temperature and apparent reflectance had been presented.In this paper,the thermal infrared temperature difference △T(T11μm-T12μm)is investigated as a possible method for detecting dust outbreaks. Previous research indicates that △T is always bigger than 0 due to vapor absorption difference in thermal infrared bands(T11μm and T12μm)when aerosol optic thickness τ0.50μm is less than 1.0.However,when radiative properties of the winter dust aerosol is incorporated into SBDART atmospheric radiative transfer model,atmospheric radiation calculations indicate that the temperature difference △T over land surface will decline below 0 as optic thickness τ0.50μm of dust aerosol increases to more than 1.7.This is due to the reason that the imaginary part of the complex refractive for dust aerosol at 11μm band is bigger than that ay 12μm band,which causes thermal infrared absorption at 11μm band is bigger than that at 12μm band. The feasibility of dust detection using this technoligy is demonstrated by comparing satellite observations and surface observations of meteoeological stations in one serious event of spring dust that occurred in North-East China on April 7,2002.