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Impact of prolonged La Nina events on the Indian Ocean with a special emphasis on southwest Tropical Indian Ocean SST

Singh, P and Chowdary, JS and Gnanaseelan, C (2013) Impact of prolonged La Nina events on the Indian Ocean with a special emphasis on southwest Tropical Indian Ocean SST. Global and Planetary Change, 100. pp. 28-37.

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Abstract

This study examines the mechanisms governing the teleconnections associated with the long-lived La Niña variability in the tropical Indian Ocean (TIO) sea surface temperature (SST) anomalies using observational and reanalysis products. Two long-lived La Niña events (1973 to 1976 and 1998 to 2001) are observed in the recent years, one falling before and the other after the mid 1970's climatic shift. The winter (boreal) and spring (November to April) TIO SST is highly influenced by long-lived La Niña forcing. Climatic shift in mid 1970s contributes to the changes in TIO SST pattern during these two long-lived La Niña events. Surface heat flux variations due to long-lived La Niña contribute to the SST changes except in the southwest TIO. The upwelling favorable local surface wind stress curl and upwelling Rossby waves originating from the east are the dominant mechanisms responsible for the La Niña related winter time SST cooling over the southwest TIO. Long-lived La Niña induced surface wind anomalies enhance the fall Wyrtki Jet in the equatorial Indian Ocean resulting large scale anomalous heat transport. Local SST cooling reduces convection and contributes to the low rainfall over southwest TIO and the northern parts of Madagascar Island

Item Type: Article
Additional Information: Copyright of this article belongs to Elsevier.
Uncontrolled Keywords: Air sea interactions; Climatic shifts; Dominant mechanism; Equatorial Indian Ocean; Heat transport; Indian ocean; Local surfaces; Madagascar; Reanalysis; Rossby wave; Sea surface temperature anomalies; Surface heat fluxes; Surface wind anomalies; Teleconnections; TiO; Tropical Indian ocean; Winter time, Atmospheric temperature; Ocean currents, Nickel compounds, air-sea interaction; climate change; El Nino; heat flux; La Nina; rainfall; Rossby wave; sea surface temperature; seasonality; surface flux; surface wind; teleconnection; upwelling, Indian Ocean; Indian Ocean (Equatorial); Indian Ocean (Tropical); Madagascar
Subjects: Meteorology and Climatology
Depositing User: IITM Library
Date Deposited: 10 Jun 2014 09:16
Last Modified: 10 Jun 2014 09:16
URI: http://moeseprints.incois.gov.in/id/eprint/393

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