黄渤海一次持续性大雾过程特征和成因分析

摘要

利用日本MTSAT-1R卫星数据、常规地面和高空观测数据、NCEP FNL客观再分析资料和NEAR-GOOS(North-East Asian Regional Global Ocean Observing System)的海表温度(SST)数据,分析了2010年5月31日至6月5日发生在黄渤海及周边地区的一次持续性海雾天气的形成、维持、消散特征及其物理机制.结果表明:大雾形成前低层水汽非常充沛,人海变性冷高压的稳定维持为这次持续性海雾过程提供了有利的背景条件,海雾在夜间辐射冷却作用下形成；大雾期间黄渤海位于人海高压后部,海面气温略高于SST,975 hPa以下有下沉逆温存在,弱冷平流的发展也有利于低层空气的冷却,对海雾的发展和维持有重要作用；气温回升和低层水汽的流失使相对湿度逐渐下降,是海雾缓慢消散的原因.%The characteristics and forming, maintaining and dissipating mechanisms of a sustained sea heavy fog occurred over the Yellow Sea, Bohai Sea, and adjoining areas from 31 May to 5 June 2010 is analyzed by means of various data, including MTSAT-1R satellite data, conventional surface and upper air observation data, FNL (objectively reanalyzed Final Analysis) data issued by NCEP and daily averaged sea surface temperature (SST) from NEAR-GOOS (North-East Asian Regional Global Ocean Observing System). The results indicate: the moisture in the low-level air was very abundant before the fog, and a transformed cold high pressure sustained stably over the Yellow Sea and Bohai Sea and provided a good background condition for the sustained sea fog, and then sea fog formed mainly in nighttime because of radiation cooling. During the fog, air temperature was just a little higher than SST, and subsidence inversion existed in the low-level air below 975 hPa. The development of cold temperature advection also contributed to the cooling of moist air in the low-level air, which played important roles in the development and sustaining of the sea fog. As air temperature rose again and the moisture dropped, relative humidity descended gradually and led the fog to disappear slowly.