Two Physical Mechanisms Controlling the Interannual Variability of Baiu Precipitation

• DOI: 10.2151/jmsj.2014-403
• Publication Date: 2014-09-25T23:33:19Z
• Authors: Tsuyoshi YAMAURA; Tomohiko TOMITA
• Keywords: Anticyclone; Teleconnection; Forcing (mathematics); Atmospheric Circulation

This work examines two physical mechanisms that control the interannual variability of Baiu precipitation from late May to mid-July, using objective analysis data atmospheric parameters including 1979 2010 and sea surface temperature (SST) 1982 2010. In June, this period, mean circulation produces is altered. early season (May 26-June 24) after a warm El Niño/Southern Oscillation (ENSO) event, an anomalous anticyclone appears in western North Pacific (WNP) through Pacific-East Asian teleconnection, which enhances precipitation. The maintained by Rossby wave response negative SST anomalies (SSTAs) WNP, persist preceding winter until period. On other hand, effect Indian Ocean capacitor essential for (June 25-July 19) ENSO event. Positive SSTAs tropical (TIO) induce specific with Matsuno-Gill pattern, forcing WNP increases occurs only season, because it necessary tropospheric heating extend northeastward TIO intraseasonal development summer monsoon. Thus, processes producing differ between seasons. Based on these differences, more detailed consideration can be given indicators precipitation, i.e., Oceans. monitoring oceans has potential improve predictions