Summary of Abstract Submission

Abstract Submission No. IO50-07-0011PresentationOral

COUPLED EL NINO/LA NINA/WALKER CIRCULATION INTERACTIONS IN THE INDIAN OCEAN

David Halpern*1

1 Jet Propulsion Laboratory, USA

ABSTRACT :

The Walker Circulation, named by Jacob Bjerknes (1897-1975), is the equatorial longitudinal-vertical zonal wind circulation segment of the Southern Oscillation, named by Gilbert Walker (1868-1958) for the interannual fluctuations of atmospheric pressure over the tropical Indo-Pacific region. In 2000-2011, the differences between El Nino and La Nina variations in sea surface temperature, rainfall, zonal winds at 10-m and 14-km heights, and near-surface phytoplankton abundance were very small in the Indian Ocean compared to those in the west Pacific Ocean (150E-150W). Comparative studies over the Atlantic and Pacific Oceans will be described, e.g., the Atlantic Walker Circulation at 10-m and 14-km heights revealed no evidence of El Nino/La Nina and a distinct influence of El Nino/La Nina, respectively. In the west Pacific, the Walker Circulation upward limb over the Maritime Continent shifted eastward 30 longitude in El Nino compared to La Nina. The relationship between All-India Rainfall, El Nino/La Nina, and Walker Circulation will be described. The following satellite datasets were used: TMI rainfall and sea surface temperature; MISR 14-km height wind vector; QuikSCAT and ASCAT 10-m height wind vector; and SeaWiFS, MODIS and MERIS chlorophyll-a. The geographical domain of satellite data was 1S-1N along the equator in 2-longitudinal increments.