BIDS/CERC-WET Data Science Fellow Zexuan Xu is a postdoc fellow in the Climate and Ecosystem Science Division at Berkeley Lab (LBNL). He uses data-driven modeling and high-performance computing to study water resources under changing climate and environmental conditions. As part of the Clean Energy Research Center for Water/Energy Technologies (CERC-WET), a US/China collaboration supported by the US Department of Energy, Zexuan’s research helps improve our understanding of the Earth’s water cycle and the strategies we use for water resources management.
To improve meteorological inputs to regional analyses of water and energy resources through modeling and evaluation, Zexuan applies the newly developed variable-resolution Community Earth System Model (VR-CESM) to provide one-eighth degree (14 km) fine resolution hydroclimate outputs for the western U.S. and eastern China, over the historical period 1970-2010 and the projection period 2010-2050. These simulations are performed on the Cori supercomputer at the Department of Energy’s National Energy Research Scientific Computing Center (NERSC). The uncertainties of this new dynamical downscaling method, which directly simulates the effects of large-scale climate processes at regional or local scales of interest, are evaluated and validated by intercomparison with observational and reanalysis datasets.
In collaboration with the scientists in BIDS/UC Berkeley, LBNL, three other UC campuses (UC Davis, UC Irvine and UCLA) and project partners in China, Zexuan’s research provides a critical resource to study water contamination, drought, the water/energy nexus, extreme events and hydropower. In California, alluvial groundwater basins contribute approximately 38% toward the State's total water supply during an average year, even up to 46% in a drought year (California Dept. of Water Resources, 2018). The global climate model and downscaling methods are particularly important for better prediction and evaluation of groundwater quantity and quality under different climate scenarios.
Hydroelectric power, another major source of California’s energy, produces 6-12% of the total in-state electricity generation but varies each year depending on rainfall (California Energy Commision, 2018). In addition, the energy that is required to extract, treat, and deliver water has a strong dependency on the spatial and temporal distribution of hydroclimate simulations, for example during extreme precipitation events (atmospheric rivers, hurricanes, etc.), droughts and heat waves. This study aims to understand how climate change as well as socio-economic factors (e.g., population growth, land use change) will affect energy production and usage in the future, and to provide insights for strategic plans, regulations and policies.