关键词: 黄海北部, 春季平流雾, 稳定层结, 特征

Abstract:  Based on the Lband sounding data, automatic weather station data, conventional observation data, NCEP global 1°×1° reanalysis data, the formation mechanism, characteristics of development processes and transmission mechanism of a persistent advection fog occurring over the north of the Yellow Sea during 23-24 April 2012 were analyzed. The results show that this fog belongs to an advection cooling fog. It was a result of interaction between cold sea surface and warmwet air flow. The sustained ridge over the Yellow Sea blocked and weakened the cold air, and it was favorable in establishment of a stable stratification in the lower layer of atmosphere. The sustained and strengthened transport of moisture by the southerly in the lower layer over the Yellow Sea not only provided abundant moisture for formation of the fog but also facilitated northward spreading of the fog areas. The “warm dry layer” above the fog layer and the underlying cold waters in the northern Yellow Sea were the primary factors for development and maintenance of this advection fog. The dense fog area corresponded to the cold advection area and the moisture convergence zone in the nearsurface layer. The area of merging of the cold and warm advections was prone to fog occurence. Under stable synoptic situation, the increase of southerly wind speed in the northern Yellow Sea did not affect maintaining of the advection fog. This unique character can be evidently distinguished from radiation fog.

Key words: northern Yellow Sea, spring advection fog, inversion layer, characteristic