Spatiotemporal Shifts in Biologic Activity Across Amazonia Forest-Cerrado Transitions and Land Conversions: an Analysis with MODIS Biophysical Products
Alfredo
Ramon
Huete, University of Arizona, ahuete@ag.arizona.edu
(Presenting)
Kamel
Didan, University of Arizona, kamel@ag.arizona.edu
Yosio
Edemir
Shimabukuro, INPE, yosio@ltid.inpe.br
Piyachat
Ratana, University of Arizona, piyachat@ag.arizona.edu
Laerte
Guimaraes
Ferreira, Universidade Federal de Goiás - UFG, laerte@iesa.ufg.br
An understanding of the spatiotemporal variations of biologic activity in the Amazon region is needed to help answer key questions on climate variability, forcing and consequences to the carbon and water cycles. High temporal frequency observations with the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Terra and Aqua Earth Observing System platforms offer unique opportunities to study climate- and anthropogenic- induced land conversions in the temporal domain. Shifts in vegetation type and physiognomies alter biologic activity and responses to climate patterns in unpredictable ways, with important consequences to the structure and functioning of ecosystems. We utilized 4 years of MODIS multi-product, time series data to analyze the seasonal and spatial patterns of photosynthetic vegetation activity over the Amazon basin and surrounding regions of Brazil. Inter-annual and phenological variations were analyzed along several eco-climatic transects that extended from the cerrado and caatinga regions to the seasonal and perhumid tropical forests. The MODIS biophysical products utilized along the eco-climatic gradients included the vegetation indices (VI), leaf area index (LAI), fraction of absorbed photosynthetically active radiation (FPAR), and net primary productivity (NPP). MODIS-derived seasonal metrics, such as length of the growing season and drying periods, were found to be strongly related with fire frequency and intensity, land surface temperature, carbon flux tower measurements, and land use conversions. We found MODIS data spatiotemporal patterns to vary significantly along the eco-climatic gradients, particularly over the cerrado- forest transition and in land converted and land degraded areas.
Submetido por Alfredo R. Huete em 17-MAR-2004
Tema Científico do LBA: LC (Mudanças dos Usos da Terra e da Vegetação)