Co-variation modes of tropical Indo-Pacific SST and summer precipitation anomaly in the Haihe River basin and its application on precipitation prediction
The prediction skill of the state-of-the-art dynamic models on the Haihe River basin(HRB)summer rainfall is still limited,leaving challenges in developing statistical prediction methods.This study used observed precipitation dataset in stations and the sea surface temperature(SST)dataset of Hadley Center in the UK during 1961-2020,analyzed the interannual dominant co-variation modes of early stage SST anomalies in the tropical Indo-Pacific Ocean and the summer precipitation anomaly in the HRB,and constructed an objective precipitation prediction model by the multi-variable empirical orthogonal function(MVEOF)method.Main conclusions are as follows:(1)Previous evolution of ENSO event and tropical Indian Ocean(TIO)SST is well correlated with summer precipitation pattern over the HRB:(a)If an El Nino event reached its peak in the previous winter,began to attenuate in spring,and caused the lagged warming response in the TIO,the above normal summer precipitation in the HRB was observed,whose center was located in the north;(b)When an El Nino was converted to La Nina event in the previous autumn,with a transformation of the SST anomaly in the TIO,the summer precipitation in the HRB tended to appear"wet-west and dry-east"pattern;(c)While the Pacific meridional mode(Cold tongue mode)over the tropical Pacific in the early stages is accompanied by"wet-northwest and dry-southeast"("wet-south and dry-north")pattern in the basin.(2)The prediction model can well predict the summer precipitation in the HRB during 2013-2020,with high temporal correlation coefficient,anomaly symbol skill and wet/dry deviation skill.But its spatial prediction skill is still limited.In conclusion,this paper clarifies the statistical relationship between the seasonal evolution of SST anomalies in the tropical Indo-Pacific Ocean and the spatial distribution of summer precipitation anomaly in the HRB,and constructs an objective statistical prediction model which provides a new and effective method for short-term climate prediction in North China.
Haihe River basinSummer precipitationObjective prediction methodTropical Indo-Pacific SSTA
NETL
NSTL
万方数据
