Sectoral water usage in the Community Earth System Model (CESM)

<p><strong>Abstract:</strong></p><p>Climate change and human water management are the two main drivers of terrestrial water storage change, from regional to global scale. When thinking about the future, our main tools to project upcoming changes in the terrestrial water fluxes and storage are the Earth System Models (ESMs). Through the representation of physical, chemical and biological processes relevant to the climate dynamics, ESMs are the closest we got to represent the real Earth.</p><p>Despite important advancements in the development of ESMs, these models are still missing key elements relevant to the representation of the water cycle, notably anthropogenic water management (Nazemi and Howard, 2015). Through the construction of dams and the abstraction of water from surface and groundwater sources, humans can significantly alter the regional and continental water budget, including river discharge and seasonality, groundwater levels and surface evapotranspiration.</p><p>The objective of our current project is to reduce this gap, by enhancing the Community Earth System Model to support abstractions for all major water use sectors including domestic, livestock, thermoelectric, manufacturing, mining and irrigation. Some unique features of our development are: full coverage of human water usage for both historical (1971-2010) and future scenarios; a sectoral competition scheme when water availability is limited; application of consumption fluxes on surface soil to accentuate role of human water usage on land-atmosphere interactions; full coupling between routing-land-atmosphere-ocean components. At the moment, all abstractions are performed exclusively from surface water.</p><p>For the scope of this conference, we will present for the first time, the global simulation results for the historical period (1971-2010) in land only mode, including a general performance of the model in normal conditions and some case studies for known historical drought events.</p><p>&#160;</p><p><strong>References:</strong></p><p>Nazemi, Ali, and Howard S. Wheater. "On inclusion of water resource management in Earth system models&#8211;Part 1: Problem definition and representation of water demand." Hydrology and Earth System Sciences 19.1 (2015): 33-61.</p><p>&#160;</p>