吴战平, 白慧, 严小冬. 贵州省夏旱的时空特点及成因分析[J]. 云南大学学报(自然科学版), 2011, 33(S2): 383-391.
引用本文: 吴战平, 白慧, 严小冬. 贵州省夏旱的时空特点及成因分析[J]. 云南大学学报(自然科学版), 2011, 33(S2): 383-391.
The characteristics of the spactial and temporal distribution and the cause of formation analysis about the drought during the summer half year in Guizhou[J]. Journal of Yunnan University: Natural Sciences Edition, 2011, 33(S2): 383-391.
Citation: The characteristics of the spactial and temporal distribution and the cause of formation analysis about the drought during the summer half year in Guizhou[J]. Journal of Yunnan University: Natural Sciences Edition, 2011, 33(S2): 383-391.

贵州省夏旱的时空特点及成因分析

The characteristics of the spactial and temporal distribution and the cause of formation analysis about the drought during the summer half year in Guizhou

  • 摘要: 近30年贵州省夏半年降水量呈明显的阶段性特征,表现为少雨期-多雨期-少雨期的年代际振荡.去掉年代际趋势,对19812010年贵州夏半年降水做EOF分解,主模态的方差贡献为36%,其空间分布表现为全省同位相分布,但区域降水年际变率的空间分布不均;EOF1降水异常型在49月均有表现,尤其在7、8月份.将PC1与78月相关的水汽通量场、环流场求相关,发现贵州夏半年降水量降水偏少时,东亚-太平洋沿120E上空位势高度场呈-+-距平分布、贵州上空的异常反气旋形成和维持以及高空西风急流的异常增强是降水偏少的主要原因.另外,在典型夏半年降水偏少年份,赤道中东太平洋SST处于冷位相的次年,贵州夏半年降水偏少的概率为80%;在La Nina事件的次年,贵州夏半年降水偏少的概率为100%.表明赤道太平洋海温异常导致的大气环流异常具有稳定性和持续性,对次年夏半年贵州降水产生明显滞后效应,尤其在La Nina事件的次年,其影响更为显著.

     

    Abstract: The amount of precipitation shows clear stages in the summer half year in Guizhou,which incorporates the interdecadal timescale of the rainless-rainy-rainless stages.Without the interdecadal trend,the provincial data of the amount of precipitation in the summer half year from 1978 to 1994 is used for EOF analysis,whose the variance contribution of the first mode is 36%,the spatial distribution is the in-phase and the interannual variance of the regional precipitation is uneven.The abnormal precipitation pattern of the EOF1 is found during April to September,expecially in the July and August.Based on the coefficient of correlation between the PC1 and vapor flux field and the circulation field,we find that the -+- abnormal distribution of the geopotential height along 120E over the East Asia-Pacific,the formation and maintenance of the abnormal anticyclone over the Guizhou and abnormal increase of the upper westerly jet are the main reason for the low rain.With the the typical years,the low rain of Guizhou in summer half year account for 80%,which is following the cold-phase of the surface sea temperature(SST) in the middle and the eastern equatorial Pacific.And the low rain of Guizhou in summer half year account for 100%,which is following the LaNina.Based on above the main findings,the abnormal circulation is caused by the abnormal SST in the middle and the eastern equatorial Pacific having the stability and sustainability,and having the significant lag-effect,expecially in the following year of the LaNina.

     

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