利用NOAA卫星资料估算陆地沙尘量的方法

提出一种利用NOAA卫星可见光通道估算北方干旱陆地上空沙尘含量的方法。该方法考虑到在短时间内某一固定区域的地面反射率变化较小,因此可以利用沙尘暴发生和晴空2个不同时刻卫星测量到的这一像素区的辐射值来消除地面反射率的影响,估算陆地上空沙尘暴的光学厚度。在2002年4月6日左右沙尘暴发生期间,利用该方法计算的沙尘光学厚度与载沙量的结果和同步观测的TSP值与地面气象数据在趋势与分布上是一致的。

A METHOD FOR ESTIMATING THE AMOUNT OF AIR BORNE SAND OVER THE LAND

Using visible channels of NOAA satellites,the authors developed a new method to estimate the amount of airborne sand over the arid area in northern China.Due to the great difference in reflectance on the land,it is rather difficult to directly retrieve the dust storm from the visible radiance obtained from the satellite.Considering that the change of the land reflectance is very small during a short time in a fixed place,we can make a comparison between the radiance of the clear sky and that of the dust sky.In this way,we can estimate the optical depth of the dust storm over the land.Test results indicate that,during the dust storm on April 16,2002,the optical depth of dust storm and the airborne sand amount calculated by this method were in agreement with the trend of the synchronous TSP observation.