Potential hydrologic changes in the Amazon by the end of the 21st century and the groundwater buffer

Bibliographic Data

ID15550337
AuthorsYadu Pokhrel (0000-0002-1367-216X, Rutgers, the State University of New Jersey, corresponding author), Yadu N Pokhrel, Ying Fan (0000-0002-4147-9594, Rutgers, the State University of New Jersey), Gonzalo Miguez‐Macho (Universidade de Santiago de Compostela), Gonzalo Míguez-Macho (0000-0002-4259-7883)
Year2014
Volume9
Issue8
Pages084004-084004
Publication date2014-08-01
Peer ReviewedYes
Open AccessYes
TypeARTICLE
VenueEnvironmental Research Letters (JOURNAL)
Journal identifiersISSN: 1748-9326 • E-ISSN: 1748-9326
PublisherIOP Publishing (PUBLISHER • GB)
DOI10.1088/1748-9326/9/8/084004
OpenAlexW2167380976
LanguageEN
Citations received3
References cited61

This study contributes to the discussions on the future of the Amazon rainforest under a projected warmer-drier climate from the perspectives of land hydrology. Using IPCC HadGEM2-ES simulations of the present and future Amazon climate to drive a land hydrology model that accounts for groundwater constraint on land drainage, we assess potential hydrologic changes in soil water, evapotranspiration (ET), water table depth, and river discharge, assuming unchanged vegetation. We ask: how will ET regimes shift at the end of the 21st century, and will the groundwater help buffer the anticipated water stress in some places-times? We conducted four 10 yr model simulations, at the end of 20th and 21st century, with and without the groundwater. Our model results suggest that, first, over the western and central Amazon, ET will increase due to increased potential evapotranspiration (PET) with warmer temperatures, despite a decrease in soil water; that is, ET will remain PET or atmospheric demand-limited. Second, in the eastern Amazon dry season, ET will decrease in response to decreasing soil water, despite increasing PET demand; that is, ET in these regions-seasons will remain or become more soil water or supply-limited. Third, the area of water-limited regions will likely expand in the eastern Amazonia, with the dry season, as indicated by soil water store, even drier and longer. Fourth, river discharge will be significantly reduced over the entire Amazon but particularly so in the southeastern Amazon. By contrasting model results with and without the groundwater, we found that the slow soil drainage constrained by shallow groundwater can buffer soil water stress, particularly in southeastern Amazon dry season. Our model suggests that, if groundwater buffering effect is accounted for, the future Amazon water stress may be less than that projected by most climate models

Amazon rainforest · Dry season · Evapotranspiration · Geography · Groundwater · Hydrology (agriculture · Surface runoff · Water resource management · Water resources · Water table · Climate variability and models · Environmental Science · Hydrology and Watershed Management Studies · Plant Water Relations and Carbon Dynamics · Ecology · Geology

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