Characteristics Analysis of Heavy Fog Events in Nanyang in Winter Half Year Based on High-resolution Data
He Zhe
Zhu Leilei
Xi Le
Li Xinmei
Wang Chunxiao
Zhang Yongtao
Wang Jue
Abstract：Based on the high-resolution datasets of hourly surface observations,MWP967KV ground-based microwave radiometer and ERA5,the characteristics of 64 heavy fog processes in Nanyang in winter half year are analyzed.The results show that December is the month to see heavy fogs most fre-quently and most serious.Whether there is precipitation in earlier stages or not,heavy fogs are always likely to occur.Even though relative humidity near the surface exceeds 90％,visibility is not necessarily of the grade of heavy fog,and it may be of mist.When there is precipitation within 24 hours before heavy fogs,the atmospheric layer with liquid water content ≥0.2 g·m-3 during the heavy fog period is thicker than that of no precipitation in the earlier stage,but there is no significant disparity between the maximum values of liquid water content near the surface in the two conditions.When heavy fog occurs,there is a wet layer near the surface,over which is a dry layer.In general,near the surface,there is convergence and positive vorticity in most cases,and there is descending motion and ascending motion,but most of them are descending motions.The absolute values of vertical motions are usually less than 0.1 Pa·s-1 or close to 0 Pa·s-1.During the heavy fog period,it is possible for cold advection and warm advection to ex-ist near the surface.The temperature inversion layer or isothermal layer plays a more important role in the occurrence of heavy fogs.
Keywords：Nanyangheavy fogground-based microwave radiometerERA5
Publication Date：2023-12-28
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：9( 1-9 )