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The Impact of Natural and Human Forcings on the Global Terrestrial Hydrology Cycle and Vegetation Dynamics for the Past Three Decades

jmao_bioDr. Jiafu Mao, Research Scientist
Ecosystems Simulations Science Group
Environmental Sciences Division
Climate Change Science Institute at ORNL
October 24th, 2014, 2:30 – 3:30 PM
John D. Tickle Engineering Building

Dr. Jiafu Mao is a research scientist with the Ecosystems Simulations Science group in the Environmental Sciences Division and the Climate Change Science Institute at ORNL. He is currently working on projects such as the incorporation of the GLM/GCAM model systems in the CESM model (iESM project), the replication and parameter improvement of soil biogeochemical module for CLM (CSSEF project), the improvement of CLM dynamic carbon allocation using the Partitioning in Trees and Soils observations (SFA project), single-factor simulation and remote sensing evaluation of CLM and CESM at various spatial-temporal scales (SFA project). Dr. Mao earned a combined MA-PhD in atmospheric sciences at the Institute of Atmospheric Physics, Chinese Academy of Sciences in 2007. During this time, he primarily researched the land ecosystem module in the global climate system model. From 2002 to 2003, he coupled an atmosphere-vegetation interaction model (AVIM) with a new generation grid-point atmosphere model and evaluated the coupled model performance regionally and globally. From 2004 to 2008, Mao established the M-SDGVM model, which was specifically designed for simulating the carbon and water cycle from point level to regional ecosystem properties over continental China at different temporal scales. After his work in China, he became a joint postdoctoral research fellow at the University of New South Wales and the Commonwealth Scientific and Industrial Research Organization (CSIRO) in Australia, where he succeeded in the linkage of the CSIRO Atmosphere Biosphere Land Exchange (CABLE) model and the National Center for Atmospheric Research’s Dynamic Global Vegetation Model (DGVM) with the MK3L model, and in the systematic evaluations and applications of the coupled models. Mao was a Postdoctoral Research Associate with ORNL from August 2009 until his staff appointment in November of 2011.

Talk Abstract: We investigated how climate change, rising atmospheric CO2 concentration, increasing anthropogenic nitrogen deposition and land use/land cover change influenced continental river flow, evapotranspiration and vegetation growth over the past three decades using the Community Land Model version 4 (CLM4). Our results show that CLM4 captures the spatial distribution and interannual variability of those important land variables well when compared to observation-based estimates. Generally, climate dominates the predicted interannual variability. Elevated atmospheric CO2 concentration stimulated vegetation growth, increased the predicted river flow, and modulated the trend of predicted evapotranspiration over most land areas. The roles of other factors such as nitrogen deposition and land use change are less pronounced and regionally dependent. Our results highlight how non-climatic factors mitigate or exacerbate the impact of climates on terrestrial water resources, vegetation growth and land surface carbon dynamics, particularly across regions with intensive human activity.

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