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The influence of vegetation on the ITCZ and South Asian monsoon in HadCM3

McCarthy, MP and Sanjay, J and Booth, BBB and Kumar, KK and Betts, RA (2012) The influence of vegetation on the ITCZ and South Asian monsoon in HadCM3. Earth System Dynamics, 3 (1). pp. 87-96.

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The role of global vegetation on the large-scale tropical circulation is examined in the version 3 Hadley Centre climate model (HadCM3). Alternative representations of global vegetation cover from observations and a dynamic global vegetation model (DGVM) were used as the landcover component for a number of HadCM3 experiments under a nominal present day climate state, and compared to the simulations using the standard land cover map of HadCM3. The alternative vegetation covers result in a large scale cooling of the Northern Hemisphere extra-tropics relative to the HadCM3 standard, resulting in a southward shift in the location of the inter-tropical convergence zone (ITCZ). A significant reduction in Indian monsoon precipitation is also found, which is related to a weakening of the South Asian monsoon circulation, broadly consistent with documented mechanisms relating to temperature and snow perturbations in the Northern Hemisphere extra-tropics in winter and spring, delaying the onset of the monsoon. The role of the Northern Hemisphere extra-tropics on tropical climate is demonstrated, with an additional representation of vegetation cover based on DGVM simulated changes in Northern Hemisphere vegetation from the end of the 21st Century. This experiment shows that through similar processes the simulated extra-tropical vegetation changes in the future contribute to a strengthening of the South Asian monsoon in this model. These findings provide renewed motivation to give careful consideration to the role of global scale vegetation feedbacks when looking at climate change, and its impact on the tropical circulation and South Asian monsoon in the latest generation of Earth System models.

Item Type: Article
Additional Information: Copyright of this article belongs to Author.This work is distributed under the Creative Commons Attribution 3.0 License.
Uncontrolled Keywords: Asian monsoon; Convergence zones; Earth system model; Global scale; Indian monsoon; Land cover; Northern Hemispheres; Tropical climates; Vegetation change; Vegetation cover; Vegetation feedbacks; Vegetation model, Atmospheric thermodynamics; Climate change; Climate models; Computer simulation; Experiments; Vegetation, Tropics, air temperature; atmospheric circulation; climate change; climate modeling; Hadley cell; intertropical convergence zone; monsoon; Northern Hemisphere; precipitation (climatology); snow; tropical environment; vegetation cover, South Asia
Subjects: Meteorology and Climatology
Depositing User: IITM Library
Date Deposited: 04 Jan 2014 17:41
Last Modified: 04 Jan 2014 17:41

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