沙尘暴辐射强迫的锋生过程分析

THE ANALYSIS OF FRONTOGENESIS PROCESS FORCED BY DUST RADIATIVE HEATING

本文利用锋面方程结合数值模式结果讨论了在沙尘辐射强迫下,影响锋生过程的物理机制,计算了不同的沙尘分布对这种锋生过程的影响。计算和分析结果表明:白天锋生主要是由非绝热加热和水平速度变形场共同产生的,垂直速度场对锋生的影响较弱,主要起锋消作用。水平温度梯度的平流对锋生(消)的影响都很小。晚上影响低层锋消的主要因子是非绝热加热项。 当沙尘降低时,沙尘辐射强迫的锋面强度和坡度都相应地减小。沙尘暴区中心上空的等熵混合层厚度也随之减少。

In this paper, the physical mechanism affected the frontogenesis process under force of dust radiative heating is discussed by using frontal equation and the results of two-dimension numerical model simulation. The effect of the distribution of dust on the frontogenesis process is also calculated. The calculation and analysis results indicate: In daytime, frontogenesis is mainly produced by diabatic heating and horizontal velocity deformation field. The effect of vertical velocity field on the frontogenesis is weak, it mainly result in frontolysis. The horizontal advection term contribute little to the frontogenesis and frontolysis. In night, the diabatic heating term is dominant factor which results in frontolysis.When dust descent, both the frontal intension and slope, as well as the isentropic potential temperature layer above duststorm center, decrease.