AO与ENSO对云南冬春季降水分布的影响

The influence of AO and ENSO on distribution of Yunnan winter and spring precipitation

利用1961—2012年云南124个气象观测站资料、北极涛动(AO)指数及Nio34区海温指数资料,分析了AO及海温异常对云南冬春季降水分布的影响,表明1冬季AO指数处于正位相时,云南冬季降水全省一致偏多;当AO处于负位相时,云南冬季降水全省一致偏少.AO处于正位相时,云南大部分地区春季降水以偏多为主;当AO处于负位相时,云南大部地区春季降水一致偏少.2Nio34区海温处于正位相时,云南冬季降水东部偏少其余大部偏多;当Nio34区海温处于负位相时,云南冬季降水全省一致偏少.Nio34区海温处于正位相时,云南春季降水几乎一致偏少;当Nio34区海温处于负位相时,云南春季降水一致偏多.3海温和AO对云南冬春季的联合影响分析也表明冬季降水受AO的影响较明显,而春季降水受海温异常影响较明显.4ENSO暖事件有利于AO对云南冬季降水的影响,AO与云南冬季降水成显著正相关.ENSO冷事件时AO对云南冬季降水几乎没有影响.ENSO事件发生时AO对云南春季降水的影响都不显著.这说明ENSO在AO对云南冬季降水的调制作用较春季明显.5在冬春季降水预测时,冬季可能应该主要关注北极涛动(AO)多于海温;春季可能应该着重于海温异常多于AO.

Based on Yunnan 124 observation stations data,Arctic Oscillation（ AO） Index and Nio34 Index,the influence of AO and sea surface temperature（ SST） anomaly on the distribution of the winter（ spring） precipitation in Yunnan have been analyzed.The results show that firstly,during winter,when AO is positive or negative phase,Yunnan precipitation（ YNP） will rise or fall all year around. During spring,when AO is positive phase,YNP will increase at most places. To the negative phase of AO,YNP will drop at most places. Secondly,when Nio34 SST is at positive phase,Yunnan winter precipitation will increase at most places except eastern areas.While it is at Nio34 SST negative phase,winter precipitation will increase in the whole Yunnan. During spring,when Nio34 SST is positive phase,Yunnan precipitation usually falls in almost the whole province.And Yunnan precipitation commonly increases all around under the negative phase of Nio34 SST.Thirdly,the combined influence of AO and Nio34 SST on Yunnan winter / spring precipitation shows that winter and spring precipitation is affected by AO（ Nio34 SST） more obviously.Fourthly,the influence of AO on Yunnan winter precipitation can be promoted by ENSO warm episode,and there is a significantly positive correlation between AO and Yunnan winter precipitation.What＇s more,AO almost has no effect on Yunnan winter precipitation when ENSO clod event happens.In addition,when ENSO event occurs,it seems that AO has little impact on Yunnan spring precipitation.This also indicates that the influence of AO on Yunnan winter precipitation is regulated by ENSO more significantly than it is to the spring precipitation.Finally,when predicating winter precipitation,more attention should be paid to AO than SST during winter,and as for spring,our attention may get reversed.