摘要
利用实况观测资料以及NCEP 6 h再分析资料,基于位涡理论和WRF模式,对2014年4月23~24日甘肃最强的一次沙尘暴过程进行数值模拟及发生机制分析。结果表明：沙尘暴过程出现伴有各气象要素＂突变＂现象,即风速加大、能见度陡降、PM10浓度陡增、地面气温和气压大幅度下降,模式模拟结果与实况一致,能够准确反映出各要素的强烈变化;此次沙尘暴过程在高空强风带和强锋区及地面冷高压、热低压以及两者过渡地带产生的地面强冷锋共同作用下发生,而河西地形的＂狭管效应＂对此次沙尘暴起加强作用;高值位涡沿着陡峭的310 K等熵面下滑时垂直涡度不断增大,致使垂直正涡度柱造成强烈上升运动,并与下沉运动相互作用,最终导致此次特强沙尘暴的发生。
Based on the observation data and 6- hour reanalysis of NECP and vortex theory,the strongest dust storm process was simulated by WRF model from 23 to 24 April 2014 in Gansu Province. On this basis,the forming mechanism of the dust storm was further analyzed by using the theory of potential vorticity. The observed data showed that the meteorological elements suddenly changed during the sand- dust storm process,wind speed increased,visibility steeply fell,concentration of PM10 spurted,ground temperature and air pressure significantly dropped. The simulated results were consistent with the observation,which could accurately reflect the tremendous change of each factor. The dust storm was affected by high level strong wind and frontal zone,surface cold high pressure and thermal low pressure,and strong cold front in their transitional zone,while the terrain of Hexi Corridor with funnelling played an important role in strengthening of the dust storm. The vertical vorticity continuously increased with the sliding down of the high value area of vortex along the steep 310 K isentropic surface,it caused the strong upward movement of airflow,and interacted with the sinking motion,which eventually led to the occurrence of the strong dust storm.
出处
《干旱气象》
2014年第6期980-988,共9页
Journal of Arid Meteorology
基金
沙漠气象基金项目(Sqj2012003)资助
关键词
中尺度数值模拟
沙尘暴
位涡守恒
mesoscale numerical simulation
sandstorm
conservation of potential vorticity
