摘要
本文利用一个10层细网格模式,在考虑边界层摩擦和积云对流参数化的基础上,设计了几种方案,就地面热通量对暴雨系统的影响进行敏感性试验,得出以下初步结果:(1)在一定的环境流场下,地面热通量对最大降水的发生时间可能发生影响,可使午后降水减小,凌晨降水加大;(2)地面热通量对降水影响的主要机制是通过改变近地层的层结稳定度来改变地面湍流系数,并与低空急流中心风速的水平分布不均相耦合,造成水平散度场和水汽辐合场的改变,并通过平流作用将此变化了的场移至雨区上空,引起雨区降水条件的改变;(3)云和CO_2对辐射和地面热通量的影响主要结果是使雨区的地面气温日变化振幅大大减小,较符合实况。
A 10-level fine mesh model with bulk PBL and deep cumulus convective parameterization were utilized to test the impact of surface heating flux on heavy rain system. The primary results show that (1) under certain environmental flow pattern, surface sensitivity heating fluxes may enhance precipitation in early morning and reduce it in the afternoon and (2) associated with the diurnal variation of the static stability near surface, the drag coefficient would be modified. When a LLJ streak situated at the upstream of rainfall region, the moisture convergence would be changed and could affect the Heavy rain development after advection.
出处
《大气科学》
CSCD
北大核心
1991年第5期106-114,共9页
Chinese Journal of Atmospheric Sciences
关键词
地面
热通量
降水
影响
Surface heating flux
Static stability
Moisture convergence
LLJ.
