Impact of a shallow groundwater table on the global water cycle in the IPSL land–atmosphere coupled model
The main objective of the present work is to study the impacts of water table depth on the near surface climate and the physical mechanisms responsible for these impacts through the analysis of land–atmosphere coupled numerical simulations. The analysis is performed with the LMDZ (standard physics) and ORCHIDEE models, which are the atmosphere-land components of the Institut Pierre Simon Laplace (IPSL) Climate Model. The results of sensitivity experiments with groundwater tables (WT) prescribed at depths of 1 m (WTD1) and 2 m (WTD2) are compared to the results of a reference simulation with free drainage from an unsaturated 2 m soil (REF). The response of the atmosphere to the prescribed WT is mostly concentrated over land, and the largest differences in precipitation and evaporation are found between REF and WTD1. Saturating the bottom half of the soil in WTD1 induces a systematic increase of soil moisture across the continents. Evapotranspiration (ET) increases over water-limited regimes due to increased soil moisture, but it decreases over energy-limited regimes due to the decrease in downwelling radiation and the increase in cloud cover. The tropical (25°S–25°N) and mid-latitude areas (25°N–60°N and 25°S–60°S) are significantly impacted by the WT, showing a decrease in air temperature (−0.5 K over mid-latitudes and −1 K over tropics) and an increase in precipitation. The latter can be explained by more vigorous updrafts due to an increased meridional temperature gradient between the equator and higher latitudes, which transports more water vapour upward, causing a positive precipitation change in the ascending branch. Over the West African Monsoon and Australian Monsoon regions, the precipitation changes in both intensity (increases) and location (poleward). The more intense convection and the change of the large-scale dynamics are responsible for this change. Transition zones, such as the Mediterranean area and central North America, are also impacted, with strengthened convection resulting from increased ET.
KeywordsGroundwater table Land–atmosphere Near surface climate IPSL-CM West African Monsoon
The authors sincerely thank two anonymous reviewers for their insightful comments. They gratefully acknowledge the financial support provided by the IGEM project ‘Impact of Groundwater in Earth system Models’, co-funded by the French Agence Nationale de la Recherche (ANR Grant no. ANR-14-CE01-0018-01) and the Taiwanese Ministry of Science and Technology (MoST). The IDRIS computational facilities (Institut du Développement et des Ressources en Informatique Scientifique, CNRS, France) were used to perform all the IPSL-CM simulations.
- Berg A, Findell K, Lintner B, Giannini A, Seneviratne SI, van den Hurk B, Lorenz R, Pitman A, Hagemann S, Meier A, Cheruy F, Ducharne A, Malyshev S, Milly PCD (2016) Land-atmosphere feedbacks amplify aridity increase over land under global warming. Nat Clim Change 6:869–874. doi: 10.1038/nclimate3029 CrossRefGoogle Scholar
- Burkey J (2006) A non-parametric monotonic trend test computing Mann–Kendall Tau, Tau-b, and Sens Slope written in Mathworks-MATLAB implemented using matrix rotations. King County, Department of Natural Resources and Parks, Science and Technical Services section. Seattle. Washington. USA. http://www.mathworks.com/matlabcentral/fileexchange/authors/23983. Accessed Nov 2015
- Cheruy F, Campoy A, Dupont J-C, Ducharne A, Hourdin F, Haeffelin M, Chiriaco M, Idelkadi A (2013) Combined influence of atmospheric physics and soil hydrology on the simulated meteorology at the SIRTA atmospheric observatory. Clim Dyn 40:2251–2269. doi: 10.1007/s00382-012-1469-y CrossRefGoogle Scholar
- Fouquart Y, Bonnel B (1980) Computations of solar heating of the Earth’s atmosphere: a new parametrization. Contrib Atmos Phys 53:35–62Google Scholar
- Habets F, Boé J, Déqué M, Ducharne A, Gascoin S, Hachour A, Martin E, Pagé C, Sauquet E, Terray L, Thiéry D, Oudin L, Viennot P (2013) Impact of climate change on surface water and ground water of two basins in Northern France: analysis of the uncertainties associated with climate and hydrological models, emission scenarios and downscaling methods. Clim Change 121:771–785. doi: 10.1007/s10584-013-0934-x CrossRefGoogle Scholar
- Hourdin F, Foujols MA, Codron F, Guemas V, Dufresne JL, Bony S, Denvil S, Guez L, Lott F, Ghattas J, Braconnot P, Marti O, Meurdesoif Y, Bopp L (2013) Impact of the LMDZ atmospheric grid configuration on the climate and sensitivity of the IPSL-CM5A coupled model. Clim Dyn 40:2167–2192. doi: 10.1007/s00382-012-1411-3 CrossRefGoogle Scholar
- Koster RD, Sud YC, Guo Z, Dirmeyer PA, Bonan G, Oleson KW, Chan E, Verseghy D, Cox P, Davies H, Kowalczyk E, Gordon CT, Kanae S, Lawrence D, Liu P, Mocko D, Lu C, Mitchell K, Malyshev S, McAvaney B, Oki T, Yamada T, Pitman A, Taylor CM, Vasic R, Xue Y (2006) GLACE: the global land–atmosphere coupling experiment. Part I: overview. J Hydrometeorol 7:590–610. doi: 10.1175/JHM510.1 CrossRefGoogle Scholar
- Morcrette JJ, Smith L, Fouquart Y (1986) Pressure and temperature dependence of the absorption in longwave radiation parametrizations. Contrib Atmos Phys 59:455–469Google Scholar
- Seneviratne SI, Corti T, Davin EL, Hirschi M, Jaeger EB, Lehner I, Orlowsky B, Teuling AJ (2010) Investigating soil moisture-climate interactions in a changing climate: a review. Earth Sci Rev 99(3–4):125–161. doi: 10.1016/j.earscirev.2010.02.004
- Taylor RG, Scanlon B, Döll P, Rodell M, van Beek R, Wada Y, Longuevergne L, Leblanc M, Famiglietti JS, Edmunds M, Konikow L, Green TR, Chen J, Taniguchi M, Bierkens MFP, MacDonald A, Fan Y, Maxwell RM, Yechieli Y, Gurdak JJ, Allen DM, Shamsudduha M, Hiscock K, Yeh P, Holman I, Treidel H (2013) Groundwater and climate change. Nat Clim Change 3:322–329. doi: 10.1038/NCLIMATE1744 CrossRefGoogle Scholar