cloudiness from geo-stationary satellites (GOES) has produced the strongest

evidence of the impact of land cover over the deforested Amazon on the

development of convective clouds shown by a number of previous studies.

Shallow clouds are prone to appear over deforested surfaces while high clouds

occur over forested surface but much less frequently. A understanding of the

physical mechanisms responsible for the observations was made possible by

using simultaneous measurements of atmospheric sounding at a forest and a

pasture site during the Rondonian Boundary Layer Experiment (RBLE-3). We

demonstrate that the atmospheric boundary layer over the forested area is more

unstable characterized by great values of the convective available potential

energy (CAPE) than over the deforested area. More active shallow convections

over the deforested area than deep convections over the forest was caused by

stronger lifting mechanism mainly due to the mesoscale circulations driven by

deforestation induced surface heterogeneities. We also found that smoke from

biomass burning in the deforested area significantly reduced the formation of

shallow clouds arguably through reducing the drop sizes of cloud water.