Abstract: Based on the derivation of the formula of channel IR4 albedo, the data including the brightness temperature and the albedo of channel IR4 was applied to analyze a case of the precipitation in summer in Beijing. The results show that channel IR4 albedo will increase and then decrease significantly before the precipitation is generated. Channel IR4 has an earlier feedback on the precipitation than long-wave infrared (IR1) channel and water vapor (WV) channel. In the weak echo phase after heavy precipitation, the brightness temperatures of channel IR1 and WV will continue to decrease while the temperature and albedo of channel IR4 continue to increase. Correspondingly, the appearance of the minimum brightness temperatures of channel IR1 and WV is later than the appearance of the maximum echo of the weather radar.

Key words: geostationary meteorological satellite, channel IR4, albedo, precipitation, weather radar

摘要： 在推导IR4通道反照率反演公式的基础上, 将IR4通道亮温及其反照率计算结果用于北京地区夏季降水过程的个例分析。结果表明: IR4通道反照率在降水形成前会出现明显的先升后降的现象, 对降水的反馈早于红外长波(IR1)和水汽(WV)通道; 在强降水后的弱回波阶段, IR1和WV通道亮温会继续下降, 极值位置延迟于雷达最强回波位置, 而IR4通道亮温和反照率这一阶段的变化趋势与以上2个通道相反。

关键词: 静止气象卫星, IR4通道, 反照率, 降水, 天气雷达