Relationship Between Precipitation Over Low Latitude Plateau In Early Summer And Sea Surface Temperature In The Southeastern Pacific And The Possible Underlying Mechanisms

In this paper,by using the precipitation data acquired from 187 stations,the spatial and temporal distribution of the precipitation in May(from 1979—2010)over low latitude plateau,the sea surface temperature data provided by Hadley centre,the global atmospheric circulation dataset of NCEP/NCAR Reanalysis,we analysed the relationship between precipitation in early summer over low latitude plateau and sea surface temperature in the southeastern pacific.The results show that:(1)There exist significant inter-annual variation in the early summer precipitation over low latitude plateau,which have an obviously positive correlation with sea surface temperature in the southeastern pacific.We found that the significantly positive(negative)SSTA in the southeastern pacific is associated with the more(less)precipitation over low latitude plateau.(2)Early sea surface temperature in southeastern pacific could continue into May,which could cause the atmosphere circulation anomaly in the meantime,and then the rainfall in low latitude plateau changed.We also analyse the impact mechanism:The SST cold(warm)anomalies in the southeastern pacific can cause an anticyclone high pressure over this key area,which could excite teleconnection wave train.And then,this wave can propagate to the Mascarene located in the downstream area along the PSA(Pacific—South American)wave.Mascarene high will influence the intensity of the cross-equatorial flow,and then the transportation of the water vapour to low latitude plateau will have a change.Finally,the precipitation over low latitude plateau will be changed.(3)We also found that the relationship between the early summer precipitation between low latitude plateau and sea surface temperature in the in the southeastern pacific can be modulated by Interdecadal Pacific Oscillation(IPO).When IPO is in positive(negative)phase,correlations between SSTA and precipitation will increase(reduce).