https://scholars.lib.ntu.edu.tw/handle/123456789/364074
Title: | Interannual relationships between the tropical sea surface temperature and summertime subtropical anticyclone over the western North Pacific | Authors: | Chung, P.-H. CHUNG-HSIUNG SUI Li, T. |
Issue Date: | 2011 | Journal Volume: | 116 | Journal Issue: | 13 | Source: | Journal of Geophysical Research Atmospheres | Abstract: | The interannual variability of the Western North Pacific Subtropical High (WNPSH) in boreal summer is investigated with the use of the NCEP/NCAR Reanalysis Data. The most significant change of the 500 hPa geopotential height field appears at the western edge of the WNPSH, with dominant 2-3 year and 3-5 year power spectrum peaks. The 2-3 year oscillation of the WNPSH and associated circulation and sea surface temperature (SST) patterns possess a coherent eastward propagating feature, with a warm SST anomaly (SSTA) and anomalous ascending motion migrating from the tropical Indian Ocean in the preceding autumn to the maritime continent in the concurrent summer of a strong WNPSH. A strong WNPSH is characterized by anomalous anticyclonic circulation and maximum subsidence in the western North Pacific (WNP). The anomalous WNPSH circulation has an equivalent barotropic vertical structure and resides in the sinking branch of the local Hadley circulation, triggered by enhanced convection over the maritime continent. A heat budget analysis reveals that the WNPSH is maintained by radiative cooling. The 3-5 year oscillation of the WNPSH exhibits a quasi-stationary feature, with a warm SSTA (anomalous ascending motion) located in the equatorial central eastern Pacific and Indian Ocean and a cold SSTA (anomalous descending motion) located in the western Pacific. The anomaly pattern persists from the preceding winter to the concurrent summer of a high WNPSH. The greatest descent is located to the southeast of the anomalous anticyclone center, where a baroclinic vertical structure is identified. The zonal phase difference and the baroclinic vertical structure suggest that the anomalous anticyclone on this timescale is a Rossby wave response to a negative latent heating associated with the persistent local cold SSTA. ECHAM4 model experiments further confirm that the 2-3 year mode is driven by the SSTA forcing over the maritime continent, while the 3-5 year mode is driven by the local SSTA in the WNP. Copyright 2011 by the American Geophysical Union. |
URI: | http://www.scopus.com/inward/record.url?eid=2-s2.0-79960507944&partnerID=MN8TOARS http://scholars.lib.ntu.edu.tw/handle/123456789/364074 |
DOI: | 10.1029/2010JD015554 | SDG/Keyword: | Climate change; Ocean currents; Surface properties; Tropics; Wind effects; Anomaly patterns; Anticyclonic circulation; Baroclinic; Barotropic; Eastern pacific; Enhanced convection; Geopotential height; Hadley circulation; Heat budget analysis; Indian ocean; Interannual; Interannual variability; Maritime Continent; Model experiments; NCEP/NCAR; Phase difference; Propagating features; Quasi-stationary; Radiative cooling; Reanalysis; Rossby wave response; Sea surface temperatures; SST anomalies; Subtropical anticyclone; Time-scales; Tropical Indian ocean; Vertical structures; Western North Pacific; Western Pacific; Atmospheric temperature; annual variation; anticyclone; atmospheric modeling; barotropic wave; cooling; data interpretation; geopotential; Hadley cell; heat budget; latent heat flux; oceanic circulation; Rossby wave; sea surface temperature; subsidence; subtropical region; summer; temperature anomaly; wave direction; Pacific Ocean; Pacific Ocean (North) |
Appears in Collections: | 大氣科學系 |
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