近60年西南地区降水异常的气候特征分析

[目的]分析1951～2010年西南地区降水气候异常的时空分布特征。[方法]利用1951～2010年西南地区44个站点和全国160个站点月降水资料,采用EOF分析、小波分析、合成分析等方法,对西南地区降水在月、季时间尺度的变化规律进行详尽的分析,且研究了旱、涝年对应的降水时空分布特征,全面揭示近60年西南地区降水气候异常的时空分布特征。[结果]西南地区降水的季节分配不均匀,为典型的单峰型,降水集中期为5～9月,峰值出现在7月;近年来秋季降水有明显变少的趋势,其他季节变化趋势不明显;该地区夏季降水的主要显著周期为14年,还存在6年以及3～4年周期振荡;涝年降水与华南地区呈同位相,与西部青、甘、新、藏交界处呈反位相,旱年与西北东部和华北地区降水呈同位相。[结论]该研究为该地区降水的预测预警提供参考依据。

Analysis on Climatic Characteristics of the Precipitation Anomaly in Southwest China in Recent 60 Years

[Objective] The research aimed to analyze temporal-spatial distribution characteristics of the precipitation anomaly in southwest China from 1951 to 2010.[Method] Based on monthly precipitation data of 44 stations in southwest China and 160 stations in China from 1951 to 2010,by using EOF analysis,wavelet analysis and composite analysis,monthly and seasonal change rules of the precipitation in southwest China were analyzed.Corresponding spatial-temporal distribution characteristics of the precipitation in drought and flood years were studied.Temporal-spatial distribution characteristics of the precipitation anomaly in southwest China in recent 60 years were revealed.[Result] Seasonal distribution of the precipitation in southwest China was uneven and was typical single-peak type.Precipitation concentrated from May to September,and peak appeared in July.In recent years,rainfall in autumn significantly became less,while that in other seasons had no obvious change.Precipitation in summer had the cycle of 14 years,another for 6 years and 3-4 years of periodic oscillations.In wet years,precipitation in southwest China had same phase with that in southern China,and anti-phase with that in the junction of Qinghai,Gansu,Xinjiang and Xizang.In dry years,precipitation in southwest China had same phase with that in the eastern part of northwest China and northern China.[Conclusion] The research provided reference basis for prediction and warning of the precipitation in the zone.