ENSO impacts on temperature over South Korea

Abstract

The climatic impact of the two phases (warm/cold) of ENSO phenomena on monthly temperature patterns over South Korea is examined based on the composite and harmonic analysis. The core regions, namely the north-east region and the south-west region, were identified with a high-level spatial coherence and temporal consistency, which represent the geographical extent and magnitude of the response of the ENSO forcing to the temperature patterns. For the both regions, the temperature anomalies in El Nino year are below normal for summer through fall of the ENSO year and above normal for winter through spring of the following year. The spatial coherence rates of each region are 0.95, 0.97 and the temporal consistency rates are 0.70/0.70 (cold/warm) and 0.70/0.80 (cold/warm), respectively. On the other hand, in case of the cold events, the temperature anomalies for the both regions are above normal for summer through fall of the episode year and below normal for winter through spring of the following year. The spatial coherence rates of each region are 0.98, 0.99 and the temporal consistency rates are 1.00/0.78 (warm/cold) and 0.89/0.78 (warm/cold), respectively. According to the comparative analyses for both extreme episodes in two core regions, the El Nino/La Nina–temperature relationships show reverse patterns of sign, negative–positive and positive–negative temperature anomalies, respectively. Based on the results of annual cycle analysis, Mann–Whitney U test and cross-correlation analysis, the cold–warm anomalies during the warm event years are more remarkable and significant than the warm–cold departures during the cold event years. Consequently, the climatic teleconnective pattern between the extreme phase of SO and mid-latitude temperature is identified over South Korea.