一次强沙尘暴天气的数值模拟研究

Research on the numerical simulation of a strong sandstorm

用NCEP(1°×1°)资料和GRAPES_SDM沙尘暴模式,对发生在中国北方的"20060409-11"强沙尘暴天气过程进行了数值模拟,并利用位涡理论对此次沙尘暴过程的发生机制进行了研究。结果表明:⑴强斜压槽触发了此次强沙尘暴天气,稳定的高原高压脊对低压槽的阻滞作用是沙尘暴能够维持较长时间的原因;⑵GRAPES_SDM成功模拟出此次强沙尘暴过程天气系统和发生区域,表明它是研究沙尘暴天气的有利工具;⑶此次沙尘暴过程发生的机制是:高层位涡梯度增大,使位涡锋生增强,导致高空急流产生;高空急流通过地面沙尘区域时,导致了地面风速增强而产生沙尘暴。

By using NCEP（1°×1°）data and GRAPRS_SDM sandstorm model, a numerical simulation was done to the ＂20060409 - 11＂ strong sandstorm. Then the mechanism research was carried on using the potential vorticity theory. The results showed that ： （ 1 ） This strong sandstorm was touched off by strong tilted trough and the retardative function of high ridge to low trough was the reason for the sandstorm to maintain more long time. （2） The weather system which induced the strong sandstorm and sand area were successful simulated by the GRAPES SDM sandtorm model, so it was a very useful tools to research the sandstorm;（3 ）The mechanism of this strong sandstorm was the aggrandizement of PV gradient boost up the PV frontogenesis,which induced the high jet come into being. When the high jet overpass the sand regions, it induced the swell of surface wind, which induced the happening of sand -dust storm.