2002 Annual

Thursday, 17 January 2002: 10:30 AM
Modeling the impact of the Amazon deforestation in South American climate with the Eta/SSiB model
Clemente A. S. Tanajura, Laboratorio Nacional de Computacao Cientifica, Petropolis, Rio de Janeiro, Brazil; and S. C. Chou and Y. Xue
Two one-month integrations with the Eta regional model coupled to the Simple Simplified Biosphere model (SSiB) were performed for November 1997. One had rainforest vegetation cover and the other assumed woodland type. The goals are to investigate the climatic effects of the Amazon deforestation in the Amazon and in other South American regions. The model resolution was 80 km in the horizontal and 38 levels in the vertical. Both integrations had the same initial and lateral boundary conditions, which were NCEP analyses with resolution T062L28. Therefore, the single difference in the model integrations was the change of vegetation type in the Amazon region.

The regional model run with realistic vegetation, called the control run, produced precipitation and circulation patterns close to observations and the NCEP re-analysis. Substantial differences in the dynamical fields were verified under the new scenario. There was a reduction of the monthly mean precipitation in the eastern Amazon (more than 6 mm/d) and in southern Brazil (more than 4 mm/d), and an increase in southeastern Brazil (more than 4 mm/d). The latter may be associated with changes in the South Atlantic Convergence Zone (SACZ). More experiments will be performed in another periods, and with different vegetation types.

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