The study of the effect of PDO and ENSO on the monsoonal precipitation in Hong Kong

Abstract

This paper aims to analyze the Hong Kong monsoonal precipitation data in search of strong anomalies years and seasons over the past decades. The effect of positive and the negative phases of the Pacific Decadal Oscillation (PDO), and El Niño and La Niña phases of El Niño-Southern Oscillation (ENSO) on Hong Kong monsoonal precipitation were examined from a statistical perspective with corresponding measurement indice to study the interaction of the interdecal PDO and interannual ENSO and more importantly the coupling effect of the different combination of phases of them that can possibly drive the Hong Kong precipitation anomalies in monsoon seasons. Tendency of ENSO leading the PDO index is found and suggested as interannual climate change driven by ENSO is possibly influencing the decadal PDO events in longer timeframe. Results suggest that El Niño events of ENSO displays more impact to Hong Kong rainfall activity than La Niña events during the positive PDO phase whereas the opposite is found during the negative PDO phase. And strong anomalies in rainfall during the Winter and Spring are most likely to be observed during El Niño phase whenever coupled with positive PDO event.