【摘要】 [目的]研究南来气旋产生暴雪的物理机制。[方法]利用常规气象观测资料、卫星资料以及MM5模式输出资料,对2007年3月4～6日黑龙江省东部地区暴雪天气进行分析,探讨南来气旋产生暴雪的物理机制。[结果]江淮气旋北上产生暴雪,在中高纬必须有较好的冷空气与之配合,同时南来的气旋为暴雪产生提供很好的高温条件和丰富的水汽条件;暴雪的产生,必须有高低空气流密切配合,产生较强的辐合上升运动;垂直运动使大气中的能量得以转换,此次暴雪的产生高空存在较为强烈的垂直上升运动,暴雪落区位于大值区北侧。TBB云顶温度强度随时间的变化对于预报强降雪的开始时间有较好的指示作用;水汽通量散度的辐合中心、925hPa层温度露点差≤4℃区域与暴雪落区及降雪强中心有很好的对应关系,为预报暴雪的落区及强中心提供很好的参考指标。在湿位涡守恒的制约下,由于θe面的倾斜,大气水平风垂直或湿斜压性的增加能够导致垂直涡度的显著发展,θe面倾斜越大,气旋性涡度越强,越容易造成强降水天气。当高空干冷空气侵入并沿θe脊面下滑时,引发不稳定能量的释放,为暴雪产生提供所需能量,干侵入过程也是强降雪产生的过程,暴雪落区产生在θe陡峭密集区内。[结论]该研究为暴雨天气的预测预报提供理论依据。更多还原

【Abstract】 [Objective]The research aimed to study the physical mechanism of snowstorm which was generated by the cyclone south.[Method]By using the routine meteorological observation data,satellite data and MM5 model output data,the snowstorm weather in the east of Heilongjiang Province during March 4-6,2007 was analyzed,and the physical mechanism of snowstorm which was generated by the cyclone south was discussed.[Result]Jiang-huai cyclone advanced northward to generate the snowstorm.In the middle and high latitudes,there must be good cold air to coordinate.Meanwhile,the cyclone south provided the good high temperature condition and the rich water vapor condition for the snowstorm generation.The generation of snowstorm must have the close coordination of high and low level airflows,and the strong convergence ascending movement was generated.The vertical movement made that the atmospheric energy could be transformed.When the snowstorm was generated,there was the strong vertical ascending movement in the high altitude.The snowstorm falling zone was in the north side of big value zone.The variation of TBB cloud top temperature intensity as the time had the good guidance role for forecasting the starting time of strong snowfall.The convergence center of water vapor flux divergence and the zone where the temperature drew point difference in 925 hPa layer ≤ 4 ℃ had the good corresponding relationships with the snowstorm falling zone and the snowfall strong center.It provided the good reference index for forecasting the falling zone and strong center of snowstorm.Under the restriction of moist potential vorticity conservation,for θe surface leant,the atmospheric horizontal wind was vertical,or the wet baroclinicity increased,which could cause the significant development of vertical vorticity.The bigger θe surface was,the stronger the cyclonic vorticity was.It was easy to cause the strong precipitation weather.When the high-altitude dry cold air invaded and glided along θe crestal plane,the unstable energy released,which provided the energy for the snowstorm generation.The dry invasion process was also the strong snowfall generation process,and the snowstorm falling zone was in the steep and intensive zone of θe.[Conclusion]The research provided the theory basis for the forecast and prediction of rainstorm weather.更多还原