应用米氏理论选择气象卫星探测沙尘暴的波段

Application of Mie Theory in Dust Channel Selection of Meteorological Satellite

无论从时间尺度还是从空间尺度来看,气象卫星都是监测沙尘天气的重要手段。为了使气象卫星能在监测和预测沙尘暴中最大限度地发挥其作用,探测波段的选择是十分重要的。根据米氏理论对沙尘气溶胶的散射和消光等特性进行了计算,并根据其消光作用对气象卫星探测波段的选择作了分析。通过计算得出可见光波段是探测沙尘气溶胶的主要通道,短波红外波段对沙尘气溶胶也很敏感。同时,由于沙尘粒子对不同波段的吸收也不同,可采用不同红外探测波段的辐射亮温来综合判别沙尘区。

Meteorological satellite is main detecting tool in distinguishing weather phenomena such as dust storm, considering both time resolution and space resolution. In order to exert the effect of the meteorological satellite mostly on distinguishing and forecasting dust storm, channel selection of detecting dust storm is the key point. By applying Mie theory to calculate scattering and extinction characteristics of dust particles, we analyze dust channel selection of meteorological satellite according as the extinction characteristics. According to calculation, visible channel is the main channel in detecting dust particles. Short-wave IR also has some sensitivity to dust observation. At the same time, the radiative temperature of dust particles in shortwave infrared and longwave infrared is different mainly because emissivity is the function of wavelength. We consider to apply the difference of two infrared wave bands to distinguish dust storm.