Negative ocean-atmosphere feedback in the south atlantic convergence zone .

• Grant number: 07/05016-1
• Support Opportunities: Regular Research Grants - Publications - Scientific article
• Start date: September 01, 2007
• End date: December 31, 2007
• Field of knowledge: Physical Sciences and Mathematics - Oceanography - Physical Oceanography
• Principal Investigator: Roberto Antonio Ferreira de Almeida
• Grantee: Roberto Antonio Ferreira de Almeida
• Host Institution: Instituto Nacional de Pesquisas Espaciais (INPE). Ministério da Ciência, Tecnologia e Inovação (Brasil). São José dos Campos , SP, Brazil

Abstract

The temporal evolution of the coupled variability between the South Atlantic Convergence Zone (SACZ) and the underlying sea surface temperature (SST) during austral summer is investigated using monthly data from the NCEP/NCAR reanalysis. A maximum covariance analysis shows that the SACZ is intensified [weakened] by warm [cold] SST anomalies in the beginning of summer, drifting northward. This migration is accompanied by the cooling [warming] of the original oceanic anomalies. The results confirm earlier analyses using numerical models that suggest the existence of a negative feedback between the SACZ and the underlying South Atlantic SST field. A linear regression of daily anomalies of SST and omega at 500 hPa to the equations of a stochastic oscillator reveals a negative ocean--atmosphere feedback in the western South Atlantic, stronger during January and February directly underneath the oceanic band of the SACZ. (AU)