The influence of the south Atlantic circulation in the modes of variability of the equatorial Atlantic: a study with a coupled ocean-atmosphere model

• Grant number: 06/03949-8
• Support type: Scholarships abroad - Research
• Effective date (Start): January 01, 2007
• Effective date (End): February 28, 2007
• Field of knowledge: Physical Sciences and Mathematics - Oceanography
• Principal Investigator: Edmo José Dias Campos
• Grantee: Edmo José Dias Campos
• Host: Reindert Julius Haarsma
• Home Institution: Instituto Oceanográfico (IO). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Local de pesquisa : Royal Netherlands Meteorological Institute, Netherlands

Abstract

The influence of the South Atlantic circulation in the variability of the tropical Atlantic is being investigated with a coupled ocean-atmosphere model, through cooperation between scientists of IOUSP and KNMI. This cooperation has been supported by FAPESP by means of different projects, including two visits of Dr. Haarsma to Brazil. In the first, from 01/08/2002 to 31/07/2003, it was conducted a study on the South Atlantic modes of variability. Results of these studies have provided material for two articles published in first class journals, presentations in international scientific meetings and Doctoral Dissertation. In the second visit, from 1/4 and 27/06/2006, it was performed experiments with the objective of understanding the role of the South Atlantic circulation in the variability of the tropical Atlantic. In this study, in addition to a CONTROL experiment, two other simulations were done. In the first (NOAGU), the "leaking" of waters from the Indian Ocean to the Atlantic was shut down. The second (NOMOC) was simulation with the total colapse of the Atlantic Meridional Overturning Cell (MOC).Results of the NOAGU show that the upper layers in the tropical Atlantic become cooler and fresher. However, the impact in the tropical variability is small. On the other hand, in the second experiment, the tropical Atlantic results warmer and saltier, with large alterations in its variability. The equatorial model of variability, equivalent to the El Niño in the Atlantic, practically disappears and the sea surface temperature variability is dominated by variations in the Benguela Current region. During the second half of 2006 additional experiments and analyses will be conducted by means of remote cooperation. For the conclusions and finalizations of articles to be submitted to publication, the present project is being submitted to FAPESP seeking financial support for a visit of Prof. Campos the KNMI, during the months of January and February of 2007. (AU)