江苏地区夏季一次辐射雾的数值模拟及生消机理分析

利用地面观测资料、秒级探空资料结合WRF中尺度数值模式,对2016年6月25—26日江苏南部地区一次影响范围广、持续时间长的罕见辐射雾过程进行了数值模拟分析。结果表明:(1)雾区范围和气象要素数值模拟结果与实况基本一致;(2)低层超薄超强逆温为此次夏季雾的形成、发展和维持提供了稳定条件;(3)成雾前江苏南部地区白天出现的降水是夜间浓雾形成的重要水汽来源;(4)夜间地表辐射冷却作用是浓雾形成的重要因素;地面风速稳定低于2 m·s^-1,有利于浓雾的维持;日出后随着短波辐射增强风速增大、稳定层结破坏促使浓雾减弱消散。

Numerical simulation and mechanism analysis of a summer radiation fog in Jiangsu Province

Based on the ground-based observations,the second level radiosonde data and WRF mesoscale numerical model, the numerical simulation analysis was carried out for a radiation fog process with a wide range of influence and long duration in southern Jiangsu Province from 25 to 26 June, 2016. The results show that: (1) the numerical simulation results of fog area and meteorological elements are basically consistent with the actual situation. (2)The ultra-thin and ultra-strong low-altitude temperature inversion provides a stable condition for the formation, development and maintenance of the summer fog.(3) The precipitation during the day in southern Jiangsu Province is the important source of water vapor for the formation of dense fog at night. (4) The cooling effect of surface radiation at night is an important factor in the formation of dense fog. The stability of near-surface wind speed is less than 2 m·s^-1, which is conducive to the maintenance of dense fog. After sunrise, the dense fog weakens and dissipates with the increase of short wave radiation and wind speed, and the destruction of the stable stratification.