Effect of land-atmosphere coupling strength on impacts from Amazonian deforestation

Abstract

We use a global climate model to explore how increasing the spatial scale of deforestation affects rainfall and temperature over Amazonia. We gradually increase the scale of deforestation separately over a "weakly" and a "strongly" land-atmosphere coupled region. The rate at which deforestation triggers a response in air temperature increases faster when deforestation is imposed on a strongly coupled region, especially during the dry season. A small deforestation signal in a strongly coupled region can have a larger impact on temperature than a large deforestation signal in a weakly coupled region. Capturing the impact of deforestation, therefore, requires the perturbation to be colocated with the appropriate land-atmosphere coupling strength. It is unclear from our results whether the impact of deforestation on rainfall depends on coupling strength. Reducing these uncertainties will require larger ensembles of model simulations to be interpreted in the context of coupling strength.