中文摘要：

为了研究空气中的水汽层结变化对雾、霾生消的影响，对北京2011年10月至2012年2月雾、霾天气个例中能见度变化和地基微波辐射计观测的相对湿度及液态水含量资料进行分析，结果表明：大气总液态水含量时序图对预报雾、霾没有参考意义，无论是大气总液态水含量数值的大小，还是大气总液态水含量随时间的变化都不能预测雾、霾的生成与消散。但不同时刻大气液态水含量的廓线图对雾、霾天气的预报还是具有指示意义的，因为雾、霾生消前后大气液态水含量层结变化明显。进一步分析不同情况的雾、霾天气发现：雾、霾生消前后均无降水出现和先出大雾后降水的情况，即降水后消散的雾、霾天气，大气相对湿度的变化和液态水含量的变化主要集中在3 km以下；对于先降水后出大雾的情况，整层大气相对湿度的变化都很明显，液态水含量的变化主要在3～7 km之间。由于降水既可以增加近地面的空气湿度，又可以消耗空气中的水汽，因此降水既是大雾形成的有利条件，也是大雾消散的有利条件。有降水出现的大雾天气，有饱和层（空气相对湿度达到或接近100%），无降水出现的重霾天气，则没有饱和层，且整体相对湿度偏低。

英文摘要：

To study the effects of the stratification changes of water vapor on fog and haze, the variation of visibility relative to the liquid water content and relative humidity observed by microwave radiometer during fog and haze events from October 2011 to February 2012 in Beijing was analyzed. The sequence diagram results showed that atmospheric liquid water content is not a suitable reference for forecasting fog and haze, nor is time variation for forecasting its generation or dissipation. However, the various times in the profile diagram of atmospheric liquid water content can indicate the presence of fog and haze because the stratification of liquid water content obviously changes during the generation and dissipation of fog and haze. Further analysis on the various conditions of the fog and haze showed that variations in relative humidity and liquid water content were concentrated mainly below 3 km. Non-precipitation occurred during fog and haze; fog occurred prior to precipitation, and haze dissipated after the precipitation ended. Under the conditions of heavy fog after precipitation, the variation of atmospheric relative humidity was obvious, and the changing of liquid water content occurred between 3-7 km. Precipitation is favorable for the dissipation of fog because it can increase the humidity level near the ground and consume the water vapor in the air. Heavy fog combined with precipitation resulted in a saturated layer with relative humidity close to 100%, whereas heavy haze with no precipitation did not form a saturated layer, and the relative humidity was relatively low.