The Possible Influence of Atlantic Sea Surface Temperature Anomalies for Low-Frequency Intensity over Qinghai-Tibetan Plateau during Summer of No-ENSO Events Following Years
Quasi-biweekly oscillation of atmospheric heat source(〈Q1〉) over Qinghai-Tibetan Plateau (QTP) is significant according to many previous studies,and it can be used as a predictor of the climate change in Eastern China.In quasi-biweekly oscillation active year,Eastern China is likely to experience a fast conversion from flood to drought or from drought to flood.On the basis of NCEP/NCAR reanalysis data and daily〈Q1〉empirical orthogonal function results,standardized variance was defined as the index of Low-frequency intensity (ITPI) over QTP to describe th e low-frequency activity.The main results showed that there is an annual variance in the low-frequency activity intensity,Pacific Ocean and Atlantic Ocean can both take effects on quasi-biweekly oscillation over QTP,the main influential factor is different in different years.During the following year of the ENSO events,the tropical pacific sea surface temperature anomaly is the key factor;During the following year of the No-ENSO events,the Atlantic Ocean triple anomaly sea surface temperature is the dominant factor which can motivate the anomaly EU wave train thus affecting the atmospheric circulation.Under the same trigger condition,the positive phase of the EU wave train is in favor of the development of cloud radiant feedback and then influence the low-frequency intensity,While the negative phase of EU wave train can suppress the development of cloud radiant feedback which cause weak Quasi-biweekly oscillation of atmosphere heat source over QTP.