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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Links between topography, moisture fluxes pathways and precipitation over South America

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Author(s):
Ignacio Saurral, Ramiro [1] ; Angela Camilloni, Ines [1] ; Ambrizzi, Tercio [2]
Total Authors: 3
Affiliation:
[1] UBA, FCEN, DCAO, CIMA, CONICET, UMI, IFAECI, CNRS, Buenos Aires, DF - Argentina
[2] Univ Sao Paulo, Inst Astron Geophys & Atmospher Sci, Sao Paulo - Brazil
Total Affiliations: 2
Document type: Journal article
Source: Climate Dynamics; v. 45, n. 3-4, p. 777-789, AUG 2015.
Web of Science Citations: 6
Abstract

The Andes Cordillera plays a role in driving moisture and heat from tropical onto subtropical South America. It forces the development of a lee-side trough that covers most of western Argentina and a low-level jet that maximizes over Paraguay, eastern Bolivia and northern Argentina and is tightly linked to precipitation variability over much of central and southeastern South America. Its steep slopes and the large zonal gradients in topography between the Equator and 40 degrees S are misrepresented in climate simulations using Global Climate Models (GCM) with resolutions coarser than about 100 km, since they naturally have a poor representation of the Andes and related circulation features. This paper analyses the impact of varying artificially the altitude of the Andes Cordillera in a GCM as well as increasing the horizontal resolution to study how these variations determine moisture fluxes and precipitation over selected regions of South America. Results show that the height of the Andes is crucial in shaping moisture fluxes pathways onto subtropical South America all year long. In particular, the low-level jet is only simulated when the Andes heights are doubled. At the same time, the relationship between the Andes shape and the location of the Bolivian High in summer is also discussed. In terms of precipitation, the lowest bias in the simulations is achieved when the horizontal resolution is increased, while in particular near the Andes foothills the simulated annual rainfall is largely determined by the Mountains shape. (AU)

FAPESP's process: 08/58101-9 - Impact of the Southwestern Atlantic Ocean on South American climate for the 20th and 21st centuries
Grantee:Tercio Ambrizzi
Support Opportunities: Research Program on Global Climate Change - Thematic Grants