Climate Dynamics

, Volume 39, Issue 6, pp 1329–1348

Global effect of irrigation and its impact on the onset of the Indian summer monsoon

  • Matthieu Guimberteau
  • Katia Laval
  • Alain Perrier
  • Jan Polcher
Article

Abstract

In a context of increased demand for food and of climate change, the water consumptions associated with the agricultural practice of irrigation focuses attention. In order to analyze the global influence of irrigation on the water cycle, the land surface model ORCHIDEE is coupled to the GCM LMDZ to simulate the impact of irrigation on climate. A 30-year simulation which takes into account irrigation is compared with a simulation which does not. Differences are usually not significant on average over all land surfaces but hydrological variables are significantly affected by irrigation over some of the main irrigated river basins. Significant impacts over the Mississippi river basin are shown to be contrasted between eastern and western regions. An increase in summer precipitation is simulated over the arid western region in association with enhanced evapotranspiration whereas a decrease in precipitation occurs over the wet eastern part of the basin. Over the Indian peninsula where irrigation is high during winter and spring, a delay of 6 days is found for the mean monsoon onset date when irrigation is activated, leading to a significant decrease in precipitation during May to July. Moreover, the higher decrease occurs in June when the water requirements by crops are maximum, exacerbating water scarcity in this region. A significant cooling of the land surfaces occurs during the period of high irrigation leading to a decrease of the land-sea heat contrast in June, which delays the monsoon onset.

Keywords

Irrigation ORCHIDEE Indian monsoon Onset Mississippi 

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Matthieu Guimberteau
    • 1
  • Katia Laval
    • 2
  • Alain Perrier
    • 3
  • Jan Polcher
    • 4
  1. 1.Laboratoire de Météorologie DynamiqueUniversité de Paris 6Paris Cedex 05France
  2. 2.Laboratoire de Météorologie DynamiqueParisFrance
  3. 3.AgroParisTechUFR Physique de l’EnvironnementParisFrance
  4. 4.Laboratoire de Météorologie DynamiqueCNRSParisFrance

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