Journal
NATURE GEOSCIENCE
Volume 8, Issue 10, Pages 763-+Publisher
NATURE PUBLISHING GROUP
DOI: 10.1038/NGEO2514
Keywords
-
Categories
Funding
- Masdar Institute of Science and Technology (Masdar Institute)
- Massachusetts Institute of Technology (MIT)
- Singapore-Massachusetts Institute of Technology Alliance for Research and Technology (SMART)
Ask authors/readers for more resources
Land-use and land-cover changes have significantly modified regional climate patterns around the world(1,2). In particular, the rapid development of large-scale cropland irrigation over the past century has been investigated in relation to possible modification of regional rainfall(3-14). In regional climate simulations of the West African Sahel, hypothetical large-scale irrigation schemes inhibit rainfall over irrigated areas but enhance rainfall remotely(13,14). However, the simulated influence of large-scale irrigation schemes on precipitation patterns cannot be substantiated without direct comparison to observations(15). Here we present two complementary analyses: numerical simulations using a regional climate model over an actual, large-scale irrigation scheme in the East African Sahel-the Gezira Scheme-and observational analyses over the same area. The simulations suggest that irrigation inhibits rainfall over the Gezira Scheme and enhances rainfall to the east. Observational analyses of rainfall, temperature and streamflow in the same region support the simulated results. The findings are consistent with a mechanistic framework in which irrigation decreases surface air temperature, causing atmospheric subsidence over the irrigated area and clockwise wind anomalies (in background southwesterly winds) that increase upward vertical motion to the east. We conclude that irrigation development can consistently modify rainfall patterns in and around irrigated areas, warranting further examination of potential agricultural, hydrologic and economic implications.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available