Analysis of characteristics in the sea surface temperature variability in the East/Japan Sea

We examine the characteristics of sea surface temperature (SST) variability in the East/Japan Sea (EJS) for the period of 1891-2005 using 1 degrees x 1 degrees latitude and longitude resolution datasets from the Japan Meteorological Agency and the Hadley Centre. A significant warming trend that manifests itself more strongly over the southern part of the sea is observed. In addition, it is found in the EJS that warming during the boreal winter is more significant than that during the summer. The EJS SST index, obtained from the time series of monthly SST anomaly averaged over the western half of the EJS, where large SST anomaly standard deviation is observed, has a primary spectral density at a frequency longer than a decade and a secondary peak at the annual frequency band. The variability of the low-frequency EJS SST, which is mostly explained by that during winter, is characterized by significant warming from the early 1940s to the late 1940s and from the mid-1980s to the present. Between the two warming periods, the EJS SST variability is dominated by decadal fluctuations. Finally, we discuss possible mechanisms of the low frequency EJS SST variability in conjunction with atmospheric variability. When the northwesterly winter monsoon becomes weaker (stronger), less (greater) amount of cold air is advected to the EJS. Sensible heat loss from the sea to the air becomes smaller (greater) producing a warm (cold) SST anomaly. (C) 2010 Elsevier Ltd. All rights reserved.We greatly appreciate the many important comments by the three referees and the editor, which significantly improved the manuscript. This work was supported by the National Research Foundation of Korea Grant funded by the Korean Government (MEST) (NRF-2009-C1AAA001-2009-0093042). Y.-G. Park has been supported by "Development of Korea Operational Oceanographic System (KOOS)". C.-H. Kim has been supported by the research programs of MLTM (PM54850) and KORDI (PG47380). J.-H. Lee has been supported by "A sustainable research and development of the Dokdo"