太原市汛期旱涝规律分析

利用子波分析和合成分析等方法，分析了太原汛期降水的多时间尺度特征和造成太原汛期旱涝的大气环流异常分布。结果表明：太原市汛期降水存在准2年、10年、16年的周期；当贝加尔湖上空500hPa高度场异常偏低（高）、西太平洋副高异常偏强（弱）时，有利于太原汛期洪涝（干旱）的形成；在850hPa水平风距平场上，来自新西伯利亚岛的偏北气流在100-140°E，50°N附近分成两支，一方面使得北来的冷空气减弱，另一方面，南下后使得低纬季风增强，太原汛期偏涝。而来源于鄂霍次克海北部的偏北气流、西北太平洋的偏东气流以及贝加尔湖以东的西北气流在60°N，115-120°E附近汇合，使入侵我国东部的偏北气流风速加大，太原在一致的西北气流控制之下，汛期偏旱。

Analysis on Characteristics of Flood or Drought in Flood Season in Taiyuan City

By using methods of wavelet analysis and composite analysis, multi-time scales chracteristics of precipitation and circulation anomalies distribution of drought/flood during flood season in Talyuan are studied. The conclusions are as follows. Talyuan precipitation has the periods of quasi-2, 10, 16 years during the flood seasons. When the anomalies fields of 500hPa potential height over lake Baykal decreases （increases）, and west pacific subtropical high increases （decreases）, the flood （drought） are apt to form during the flood seasons in Talyuan.In the horizontal anomalies wind fields of 850hPa, the north flow coming from New Siberian Islands are divided into two streams nearby the 100-140° E, 50° N, on the one hand, it weaken the cold air coming from the north, on another hand, it strengthens the monsoon of low latitude after it goes southward, Talyuan is flood during the flood seasons, the north flows coming from north of Okhotsk sea, the east flows coming from north of north-west pacific, and the north-west flow coming from the east of lake Baykal are jointed nearby 60~°N, 115-120° E, makes the velocity of north wind inbreaking the east of China speed up, Taiyuan is controled by the coherent north-west flow, it is drought.