Climatic shift in patterns of shallow clouds over the Amazon

The Amazon rain forest has experienced dramatic changes in the past 50 years due to active deforestation. As of 2001, 15% of the 4,000,000 km(2) Brazilian Amazon has been deforested [Instituto Nacional de Pesquisas Espaciais (INPE), 2003]; each year, agricultural exploitation claims an estimated 13,000 km(2) of tropical forest [Achard et al., 2002]. In this paper we investigate the climatic effects caused by the observed change of the physical characteristics of the land surface (i.e., increased surface albedo, decreased root-zone depth, decreased surface roughness and decreased leaf-area index). More precisely, we examine the spatial correspondence of shallow cumulus clouds with deforestation. Through the creation of an 8-year record of thrice daily shallow cumulus cloud cover at 1 km resolution from multi-spectral satellite imagery, we quantitatively show the existence of a significant climatic shift in shallow cloudiness patterns associated with deforestation. This shift manifests itself as an enhancement of shallow cumuli over deforested patches, and has potentially important climatic, hydrologic and ecological implications.