Regional Differences in the Influence of Irrigation on Climate

Lobell, David and Bala, Govindasamy and Mirin, Art and Phillips, Thomas and Maxwell, Reed and Rotman, Doug (2009) Regional Differences in the Influence of Irrigation on Climate. In: Journal of Climate, 22 (8). pp. 2248-2255.

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Abstract

A global climate model experiment is performed to evaluate the effect of irrigation on temperatures in several major irrigated regions of the world. The Community Atmosphere Model, version 3.3, was modified to represent irrigation for the fraction of each grid cell equipped for irrigation according to datasets from the Food and Agriculture Organization. Results indicate substantial regional differences in the magnitude of irrigation-induced cooling, which are attributed to three primary factors: differences in extent of the irrigated area, differences in the simulated soil moisture for the control simulation (without irrigation), and the nature of cloud response to irrigation. The last factor appeared especially important for the dry season in India, although further analysis with other models and observations are needed to verify this feedback. Comparison with observed temperatures revealed substantially lower biases in several regions for the simulation with irrigation than for the control, suggesting that the lack of irrigation may be an important component of temperature bias in this model or that irrigation compensates for other biases. The results of this study should help to translate the results from past regional efforts, which have largely focused on the United States, to regions in the developing world that in many cases continue to experience significant expansion of irrigated land.

Item Type:	Journal Article
Publication:	Journal of Climate
Publisher:	American Meteorological Society
Additional Information:	Copyright of this article belongs to American Meteorological Society.
Department/Centre:	Division of Mechanical Sciences > Centre for Atmospheric & Oceanic Sciences
Date Deposited:	11 Dec 2009 07:43
Last Modified:	19 Sep 2010 05:33
URI:	http://eprints.iisc.ac.in/id/eprint/20558

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