Analyzing the Influence of Tropical Deforestation on the Northern Hemisphere Climate Through Atmospheric Teleconnections

Previous studies have identified the regional-scale climate response to tropical deforestation through changes to the biophysical exchanges of water, energy, and momentum between the land surface and the atmosphere; however, little is known about the effects of tropical deforestation on the global climate. Current research has focused on climate responses in the extratropics with little analyses of the mechanisms responsible for propagating the signal out of the tropics. Here, we present a detailed study of the physical processes important in propagating a signal resulting from deforestation out of the tropics to the Northern Hemisphere in winter. Through complete deforestation of the tropics we analyze changes to the deep moist convection and reductions in high-level outflow as well as the anomalous forcing of Rossby waves out of the tropics. Our study indicates that an anomalous Rossby wave forcing resulting from tropical deforestation modifies the East Asian Jet strength and structure as well as other features of the Northern Hemisphere mean circulation patterns. Furthermore, our results indicate that tropical deforestation can amplify different modes of the North Atlantic Oscillation (NAO) and Arctic Oscillation (AO) through a redistribution of atmospheric mass caused by fundamental changes to the strength and positioning of the storm tracks and synoptic eddy activity. Different modes of variability cause different climate responses across Siberia and result in anomalous changes to the low-level winds that can significantly enhance the advection of warm air into Eurasia from the south and west. While theoretical, our approach illustrates the potentially important processes connecting regional-scale changes in the tropical climate to regional-scale changes in the extratropics.