The South American Low-Level Jet Experiment

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Moisture is transported in South America westward from the tropical Atlantic Ocean to the Amazon basin, and then southward toward the extratropics. A regional intensification of this circulation to the east of the Andes Mountains is called the South American low-level jet (SALLJ), with the strongest winds found over eastern Bolivia. SALLJ is present all year and channels moisture to the La Plata basin, which is analogous to the better-known Amazon basin in terms of its biological and habitat diversity, and far exceeds the latter in its economic importance to southern and central South America in terms of hydroelectricity and food production. The relatively small SALLJ spatial scale (compared with the density of the available sounding network) has a limited understanding of and modeling capability for any variations in the SALLJ intensity and structure as well as its possible relationship to downstream rainfall.

The SALLJ Experiment (SALLJEX), aimed at describing many aspects of SALLJ, was carried out between 15 November 2002 and 15 February 2003 in Bolivia, Paraguay, central and northern Argentina, western Brazil, and Peru. Scientists, collaborators, students, National Meteorological Service personnel, and local volunteers from South American countries and the United States participated in SALLJEX activities in an unprecedented way, because SALLJEX was the most extensive meteorological field activity to date in subtropical South America, and was the first World Climate Research Program/Climate Variability and Prediction Program international campaign in South America.

This paper describes the motivation for the field activity in the region, the special SALLJEX observations, and SALLJEX modeling and outreach activities. We also describe some preliminary scientific conclusions and discuss some of the remaining questions

Centro de Investigaciones del Mar y la Atmósfera (CIMA)/CONICET Departamento de Cs. De la Atmósfera y los Océanos/Universidad de Buenos Aires, Buenos Aires, Argentina

Dirección de Meteorología e Hidrología-DINAC, Asunción, Paraguay

NOAA/NSSL, Norman, Oklahoma

UCAR/JOSS, Boulder, Colorado

INPE/CPTEC, Cachoeira Paulista, Brazil

University of Utah, Salt Lake City, Utah

Departamento de Cs. De la Atmósfera y los Océanos/Universidad de Buenos Aires, Buenos Aires, Argentina

INPE/CPTEC, Cachoeira Paulista, and University of Sao Paulo, Sao Paulo, Brazil

University of Sao Paulo, Sao Paulo, Brazil

CORRESPONDING AUTHOR: Dr. Carolina Vera, CIMA, Pab. 2, 2do Piso, Ciudad Universitaria, (1428) Buenos Aires, Argentina, E-mail: carolina@cima.fcen.uba.ar

Moisture is transported in South America westward from the tropical Atlantic Ocean to the Amazon basin, and then southward toward the extratropics. A regional intensification of this circulation to the east of the Andes Mountains is called the South American low-level jet (SALLJ), with the strongest winds found over eastern Bolivia. SALLJ is present all year and channels moisture to the La Plata basin, which is analogous to the better-known Amazon basin in terms of its biological and habitat diversity, and far exceeds the latter in its economic importance to southern and central South America in terms of hydroelectricity and food production. The relatively small SALLJ spatial scale (compared with the density of the available sounding network) has a limited understanding of and modeling capability for any variations in the SALLJ intensity and structure as well as its possible relationship to downstream rainfall.

The SALLJ Experiment (SALLJEX), aimed at describing many aspects of SALLJ, was carried out between 15 November 2002 and 15 February 2003 in Bolivia, Paraguay, central and northern Argentina, western Brazil, and Peru. Scientists, collaborators, students, National Meteorological Service personnel, and local volunteers from South American countries and the United States participated in SALLJEX activities in an unprecedented way, because SALLJEX was the most extensive meteorological field activity to date in subtropical South America, and was the first World Climate Research Program/Climate Variability and Prediction Program international campaign in South America.

This paper describes the motivation for the field activity in the region, the special SALLJEX observations, and SALLJEX modeling and outreach activities. We also describe some preliminary scientific conclusions and discuss some of the remaining questions

Centro de Investigaciones del Mar y la Atmósfera (CIMA)/CONICET Departamento de Cs. De la Atmósfera y los Océanos/Universidad de Buenos Aires, Buenos Aires, Argentina

Dirección de Meteorología e Hidrología-DINAC, Asunción, Paraguay

NOAA/NSSL, Norman, Oklahoma

UCAR/JOSS, Boulder, Colorado

INPE/CPTEC, Cachoeira Paulista, Brazil

University of Utah, Salt Lake City, Utah

Departamento de Cs. De la Atmósfera y los Océanos/Universidad de Buenos Aires, Buenos Aires, Argentina

INPE/CPTEC, Cachoeira Paulista, and University of Sao Paulo, Sao Paulo, Brazil

University of Sao Paulo, Sao Paulo, Brazil

CORRESPONDING AUTHOR: Dr. Carolina Vera, CIMA, Pab. 2, 2do Piso, Ciudad Universitaria, (1428) Buenos Aires, Argentina, E-mail: carolina@cima.fcen.uba.ar
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