【作者】 林爱兰； 郑彬； 谷德军； 李春晖； 梁建茵；

【Author】 LIN Ai-lan,ZHENG Bin,GU De-jun,LI Chun-hui,LIANG Jian-yin (Institute of Tropical and Marine Meteorology of Guangzhou/Key Open Laboratory for Tropical Monsoon,China Meteorological Administration,Guangzhou 510080,China)

【机构】 中国气象局广州热带海洋气象研究所,热带季风重点开放实验室；

【摘要】 利用1961-2005年广东省86个常规地面观测站降水资料、ERSST全球月平均海温资料以及NCEP/NCAR大气多要素资料,分析研究广东跨季节持续性干旱事件与海温外强迫之间的关系及其物理过程。结果表明,与广东持续性干旱事件相关的海温异常有赤道东太平洋海温负异常型(即LaNina型)、赤道中太平洋海温正异常型两种类型。在20世纪70年代后期之前,广东持续性干旱事件基本上属于LaNina型;在20世纪70年代后期之后,除了LaNina型,赤道中太平洋海温正异常型持续性干旱事件出现概率明显增加。可见在全球气候变暖的背景下,广东持续性干旱事件成因更复杂。近几年来广东持续性干旱事件频繁发生,与赤道中太平洋海温正异常型持续性干旱事件出现概率增加有关。LaNina型、赤道中太平洋海温正异常型与广东干旱之间都存在物理上的联系,不同的海温异常型对广东干旱影响的物理过程有所不同,即使同一种海温异常型对不同季节的影响过程也有所不同,然而所有物理过程最终都是通过改变和削弱降水所需的动力条件或水汽条件,从而造成局地干旱的发生。更多还原

【Abstract】 Relationships between trans-seasonal continuous drought events in Guangdong Province and extra-forcing of sea surface temperature(SST) are diagnosed,and the mechanisms for the relationships are discussed using the 45-yr(1961-2005) observational data of precipitation in Guangdong province,ERSST global sea surface temperature(SST) and NCEP/NCAR atmospheric variables.The results show that there are two types of SST anomaly related to continuous drought events in Guangdong which are negative SST anomaly in equatorial eastern Pacific(namely La Nina pattern) and positive SST anomaly in equatorial mid-Pacific(namely non-La Nina pattern).Continuous drought events in Guangdong remained with La Nina pattern basically before theanaphase of 1970’s decade.And after the anaphase of 1970’s decade,besides the La Nina pattern,the probability of positive SST anomaly in equatorial mid-Pacific pattern continuous drought events increased obviously.It is shown that the causes of continuous drought events in Guangdong are more complex under the background of global climate warming.The frequent occurrence of continuous drought events in Guangdong in the recent years of 21 century is related to the increasing of the probability of non-La Nina pattern.Both of La Nina and positive SST anomaly in equatorial mid-Pacific link with the continuous drought events in Guangdong dynamically.The physical processes of different types of SST anomaly impacting drought events in Guangdong are different from each other.So are the physical processes in different seasons even though for the same type of SST anomalies.However,all the processes change and weaken ultimately the dynamical conditions and water vapour required by raining,and then result in the local drought consequently.更多还原