Changes in moisture and energy fluxes due to agricultural land use and irrigation in the Indian Monsoon Belt

• Published in: Geophysical research letters 2006-07, Vol.33 (14), p.n.-n/a
• Main Authors: Douglas, Ellen M., Niyogi, Dev, Frolking, S., Yeluripati, J. B., Pielke Sr, Roger A., Niyogi, Nivedita, Vörösmarty, C. J., Mohanty, U. C.
• Format: Article
• Language: English
• Subjects: Earth sciences; Earth, ocean, space; Exact sciences and technology
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2006GL026550

We present a conceptual synthesis of the impact that agricultural activity in India can have on land‐atmosphere interactions through irrigation. We illustrate a “bottom up” approach to evaluate the effects of land use change on both physical processes and human vulnerability. We compared vapor fluxes (estimated evaporation and transpiration) from a pre‐agricultural and a contemporary land cover and found that mean annual vapor fluxes have increased by 17% (340 km3) with a 7% increase (117 km3) in the wet season and a 55% increase (223 km3) in the dry season. Two thirds of this increase was attributed to irrigation, with groundwater‐based irrigation contributing 14% and 35% of the vapor fluxes in the wet and dry seasons, respectively. The area averaged change in latent heat flux across India was estimated to be 9 Wm−2. The largest increases occurred where both cropland and irrigated lands were the predominant contemporary land uses.