Precipitation variability in September over the Korean Peninsula during ENSO developing phase

Abstract

In this study, the relationship between the El Nino-Southern Oscillation (ENSO) and precipitation variability over the Korean Peninsula is investigated. In contrast to the previously-known positive correlation between them during an El Nino developing summer and winter, we found a considerably significant negative correlation in September between Nino3 Sea Surface Temperature and Korean precipitation during ENSO developing phase. The northerly wind is only seen during El Nino developing phase and is part of the cyclonic flow over the subtropical North Pacific. The cyclonic flow over the subtropical North Pacific is induced by the subtropical diabatic heating, which is a peculiar feature during El Nino developing phase. In addition, it is demonstrated that the negative correlation is partly attributed to the tropical cyclone (TC), particularly during La Nina phase. That is, TC tends to pass through Korean Peninsula more frequently during La Nina years, which leads to more precipitation over the Korean Peninsula.