Premium
Interannual variability in the subseasonal northward excursion of the Baiu front
Author(s) -
Tomita Tomohiko,
aka Masami,
Yamaura Tsuyoshi
Publication year - 2010
Publication title -
international journal of climatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.58
H-Index - 166
eISSN - 1097-0088
pISSN - 0899-8418
DOI - 10.1002/joc.2040
Subject(s) - teleconnection , climatology , sea surface temperature , thermocline , environmental science , precipitation , rossby wave , latitude , subtropics , subtropical ridge , subtropical front , geology , atmospheric sciences , oceanography , el niño southern oscillation , water mass , geography , meteorology , geodesy , fishery , biology
The Baiu front, a quasi‐stationary front that appears in early boreal summer near the northwestern rim of the subtropical Pacific high, shows interannual variability characterised by polarity changes in precipitation anomalies during the subseasonal northward excursion in the western North Pacific (WNP). These changes are forced by motion over the fixed surface divergence/convergence anomalies in the WNP, which are regulated by the atmospheric bridge or the Pacific–East Asian (PEA) teleconnection. The PEA teleconnection is caused by the tropical sea surface temperature anomalies (SSTAs) associated with the El Niño/Southern Oscillation. The upper ocean mixed layer depth (MLD) is crucial in regulating the SSTAs in the WNP. In the tropical WNP (lower than 20°N), the large MLD (and hence large heat capacity in the upper ocean) can maintain the SSTAs for about half‐a‐year. In the mid‐latitude WNP (higher than 20°N), the development of the seasonal thermocline in early summer reduces the heat capacity, whereas the atmospheric variation modifies the SSTAs within a season. The MLD is regarded as an important parameter that controls the strength and time scale of the air–sea feedback, and the latitude of 20°N approximately separates regions where the oceanic thermal properties are active or passive for the early‐summer atmospheric circulations in the WNP. Copyright © 2009 Royal Meteorological Society