分析了河套地区9个测站1954-2005年春季(3~5月)和夏季(6~8月)降水距平百分率及对应的冬季地气形势,经对比分析地气形势可分为5种类型:(1)大涡型,(2)小涡型,(3)河套处于地热涡或地冷涡的东(西)边缘(东西相反型),(4)河套处于地热(冷)涡的南(北)边缘(南北相反型),(5)地气系统尺度很小(系统零乱型)。分析发现:"大涡型"最为稳定,河套春、夏季降水也是稳定的多或少(对大地热或冷涡);"小涡型"的稳定性不如大涡,但做夏季预测时可参考大涡型;"东西相反型"意味着河套地区在地热涡和地冷涡之间,可预测河套地区春夏季降水将是正常;当出现"南北相反"或"系统零乱"型时,预报准确率较低。

Comparing with the analyzed results of the precipitation anomalous percentage in spring(March~May) and in summer(June~August) of 1954-2005 and the corresponding winter Di-qi phase of 9 stations in Hetao area, the Di-qi phase can be divided 5 types:(1) Big vortex,(2) Small vortex,(3) The Hetao area at the edge of geothermic(cold) vortex,the East and West part of which is opposite(E-W opposite),(4) The Hetao area at the edge of geothermic(cold) vortex,the North and South part of which is opposite(E-W opposite),(5) The scale of Di-qi phase is very small(Phase in disorder).It is found that the Big vortex is the stablest,which results in the stability of more rain in geothermic vortex or less rain in cold vortex in Hetao area in spring and summer.While it's less stable of small vortex than big vortex,so when forecasting precipitation in summer we can refer to the Big vortex.The Hetao area is in the midst between geothermic vortex and coldly vortex where the phase is E-W opposite,so it can forecast the precipitation be normal in Hetao area in spring and summer.When the phase is N-S opposite or in disorder,we can not forecast precipitation accurately.