珠海三灶机场一次平流海雾的特征及成因初探

为进一步了解平流海雾的形成、发展和消散过程特点和机制,利用风廓线雷达、自动观测、探空、数值产品以及常规气象观测等资料,分析了2014年2月17—18日珠海三灶机场一次平流海雾过程的边界层温湿风三维演变特征及天气学成因。结果表明:边界层内暖湿平流输入、浅层辐合抬升、湍流加强、多层逆温结构以及夜间地面的辐射冷却有利于近地层饱和湿空气的凝结和逆温层的维持,是雾形成的主要物理机制;暖湿平流持续及湍流减弱或停歇是雾维持的原因;近地层偏北风干冷平流入侵并出现下沉气流及日间地面辐射增温使逆温层被破坏是雾消散的主要因素。

Characteristics of an Advection Sea Fog over Sanzao Airport of Zhuhai and Preliminary Investigation into the Causation

In order to learn more about the characteristics and mechanisms of the formation, development and dissipation of sea fog, the data from a wind profiler, automatic weather observation and radiosonde as well as numerical weather prediction products are used, together with conventional meteorological observations, to study the three-dimensional evolution features and synoptic causation for an advection sea fog over the Sanzao Airport of Zhuhai on February 17--18, 2014. The result is shown as follows. For the formation of this sea fog, the main physical mechanisms include the input of a warm and humid advection into the boundary layer, lifting of a shallow-layer convergence, intensification of turbulence and multi-layer inversion as well as nighttime radiative cooling at the surface. They contributed to the condensation of saturated, humid air in the near-surface layer and the maintenance of an inversion layer. The sea fog maintains because of the persistent warm and humid advection and the reduction or break of the turbulence. It then dissipates because the inversion layer is destroyed due to the intrusion of a northerly dry and cold advection, the appearance of descending draft and daytime radiative warming at the surface.