HR: 14:00h
AN: B33A-01 INVITED     [Abstracts]
TI: What is the future of Amazon forests under climate change?
AU: * Saleska, S R
EM: saleska@email.arizona.edu
AF: University of Arizona, Ecology & Evolutionary Biology, BioSciences West rm. 310, 1041 E. Lowell St., Tucson, AZ 85721, United States
AU: Huete, A
EM: ahuete@Ag.arizona.edu
AF: University of Arizona, Soil, Water, and Environmental Science, Tucson, az 85721, United States
AU: Ratana, P
EM: piyachat@ag.arizona.edu
AF: University of Arizona, Soil, Water, and Environmental Science, Tucson, az 85721, United States
AU: da Rocha, H
AF: Dept. of Atmospheric Sciences, University of Sao Paulo, Rua do Matão, 1226, Sao Paulo, SP 05508-900, Brazil
AU: Tannus, R
AF: Dept. of Atmospheric Sciences, University of Sao Paulo, Rua do Matão, 1226, Sao Paulo, SP 05508-900, Brazil
AU: Restrepo, N
AF: University of Arizona, Ecology & Evolutionary Biology, BioSciences West rm. 310, 1041 E. Lowell St., Tucson, AZ 85721, United States
AU: Kruijt, B
AF: Alterra, Wageningen University and Research Centre, Wageningen, Netherlands
AU: von Randow, C
AF: Alterra, Wageningen University and Research Centre, Wageningen, Netherlands
AB: Large changes in Amazon carbon and water cycles, as predicted to occur with climate change by some coupled carbon/climate models, are expected to have global impact. Some models predict that these forests may be vulnerable to catastrophic collapse due to global warming-induced increases in drought, whilst others do not. Hence it is critically important to understand the mechanisms of forest-climate interactions in Amazonia. In order to address this question on observable timescales, we propose investigations at annual to decadal timescales which can give insight into the mechanisms that, in the model simulations, cause forest collapse. We first investigated large-scale seasonal and spatial patterns of Amazonian carbon fluxes, and the effects of land-use conversion thereon, by combining spatially continuous satellite data from the Terra- Moderate Resolution Imaging Spectroradiometer (MODIS) with data from a network of ground-based eddy flux towers. This work showed that primary forest photosynthetic activity begins its seasonal increase in the dry season, well before onset of the wet-season, a broad pattern opposite to that predicted by ecosystem models which simulate dry-season declines in primary forest photosynthesis due to water-limitation. Extending these observations to decadal timescales, ideally through another large ENSO-scale drought, should give strong insight into the longer term mechanisms implicated in predictions of Amazon forest collapse.
DE: 0428 Carbon cycling (4806)
DE: 0429 Climate dynamics (1620)
DE: 0438 Diel, seasonal, and annual cycles (4227)
SC: Biogeosciences [B]
MN: 2007 Joint Assembly