沙尘辐射强迫锋生过程的数值模拟

THE NUMERLCAL SIMULATION OF FRON-TOGENESIS PROCESS FORCED BY DUST RADIATIVE HEATING

本文分别利用二和三维数值模式研究了沙尘暴辐射强迫的锋生过程和孤立的沙尘暴单体辐射加热对锋面环流系统的影响。结果表明:沙尘爆发时,沙尘辐射加热在大气低层导致锋生,在大气中层产生一明显的等熵位温层。水平速度场在沿锋面移动方向表现出明显的辐合(散)特征。晚上,沙尘辐射冷却导致大气低层锋消。 孤立的沙尘暴单体辐射加热在盛行风方向强迫出一个明显的垂直环流圈,它在白天较强,晚上较弱和反向。水平风场对沙尘的辐射强迫响应在不同高度上是不同的。

In this paper, the frontogenesis process forced by dust radiative heating and effect of radiative heating of an isolation duststorm on the frontal circution system are investigated by two- and three-dimension numerical models. The results show that as the duststorm outbreak, the radiative heating results in frontogenesis in lower troposhere layer in daytime and produces an obvious isentropic mixed layer above duststorm center. The horizontal velocity field along the direction of front movement displays the characteristics of typical convergence pattern. At night, the frontolysis occurs due to the radiative cooling of dust.An obvious vertical circulation along large-scale wind direction is forced by the radiative heating of the isolated duststorm. The vertical circulation is stronger in daytime and become weaker at night. The direction of the vertical circulation in daytime is opposite to that at night. The response of the horizontal wind fields on radiative heating from dust are different at different heights.