基于稳定度和能量指标作强对流天气的短时预报指标分析

主要基于1995—2001年强对流天气过程和高空探测资料,计算了K指数、A指数、位势不稳定指标以及能量平衡高度、位势不稳定能量等指标,并进行量化检验和预报指标的对比。结果表明:(1)A指数、K指数的数值大小对于强对流天气的预报具有一定效果。(2)位势不稳定指标I在安徽南方应用比北方的预报效果好,安徽南北方I的临界值有差异,北方I的临界值小,南方I的临界值大。(3)逐年的能量平衡高度和位势不稳定能量都可以分为两个阶段,第一阶段能量平衡高度高于350 hPa且处于极值是强对流天气预报的重要指标。总温度较高、饱和总温度较高、位势不稳定能量较高时,能量平衡高度较高;反之,能量平衡高度较低。这种对应关系可以通过α=0.01的显著性水平检验。(4)强对流天气过程期间,能量平衡高度较高。随着位势不稳定能量的增大,出现强对流天气的可能性也增大。

Analysis on Short-Time Forecast of Severe Convection Weather Based on Stability and Energy Indexes

Based on the severe convectionweather data and upper sounding data from 1995 to 2001,the instability and energy indexes are calculated,which are K index,A index,potential instability index,the energy balance level,potential instability energy,respectively.The tests and comparison among some indexes have been done.The results show:(1)A and K index values have some effects on forecasting severe convectionweather.(2)The forecast effect of potential instability index in south may be better than that in north.(3)The energy balanceheight and potential instability energyin every year are divided with two stages.(4)The energy balance level is rather high during the severe convectionweather.With the potential instability energy enhance,the appearance possibility of severe convection increase.