加热和水汽对两例高原低涡影响的数值试验

Numerical Simulation of the Effect of Heating and Water Vapor on Two Cases of Plateau Vortex

利用卫星黑体亮度温度(TBB)资料、NCEP1°×1°再分析资料以及中尺度非静力平衡模式MM5,对2005年7月28～29日和2009年7月29～31日两次高原低涡过程进行了控制试验以及绝热、无地表感热、地表感热加倍、无蒸发效应、无凝结潜热、无水汽等六组敏感性试验,着重讨论了2005年7月28～29日高原低涡发生、发展及结构特征演变。结果表明:控制试验模拟出的500hPa低涡中心位置和低涡结构与实况基本吻合。绝热条件对低涡形成、发展及结构变化的影响最为显著;凝结潜热、水汽对低涡的形成不具有决定性影响,但对低涡的维持以及结构特征演变起关键作用;地表蒸发潜热对低涡的发展有一定影响,无地表蒸发潜热使低涡的强度略有减弱;地表感热对低涡的影响因个例不同而有所差异,并且在低涡的不同发展阶段也不尽相同,另外还与低涡发展阶段是在白天还是夜晚有关。

By using the satellite Temperature of Brightness Blackbody（TBB） data,NCEP 1°×1° reanalysis data,and nonhydrostatic mesoscale numerical model MM5,control experiment and six sensitivity experiments which are adiabatic,no surface sensible heating,double surface sensible heating,no evaporation effect,no latent heat of condensation,and no water vapor,are performed for two cases of plateau vortex occurring during 28-29 July 2005 and 29-31 July 2009,and the happening,development,and structure change of the plateau vortex during 28-29 July 2005 are mainly discussed.The results show that the vortex center and the vortex structure at 500 hPa simulated in the control experiment are the same as actuality.The adiabatic conditions affect the formation,development and structure change of the vortex most remarkably.The latent heat of condensation and the water vapor do not play decisive roles in formation of the vortex,but play key roles in vortex maintenance and structure characteristics evolvement.Surface latent heat has some effect on the development of the vortex,and no surface latent heat slightly decreases the strength of the vortex.The effect of surface sensible heat on the vortex is different for different cases,and depends on the developing stage of the vortex,and also that the developing stage is daytime or night.