Improving Climate Modeling Utilizing Atmospheric Radiation Measurement (ARM) Data
Transpiration is one of the most efficient means of moisture transport from the land surface to the boundary layer. Researchers evaluated the integration of a photosynthesis-based gas-exchange evapotranspiration model within a land surface model for estimating the canopy resistance and transpiration using 18-month simulation data. (Canopy resistance is described as vapor flow through the transpiring crop and evaporating soil surface.) The impact of the photosynthesis-based transpiration approach on canopy resistance, surface fluxes, soil moisture, and soil temperature over different vegetation types was studied using simulated land surface fields containing ARM Southern Great Plains site data, Oklahoma Mesonet station data, 2002 International H2O Project, and Ameriflux observations. Incorporation of the gas-exchange model improves the forecast of surface energy fluxes as well as the associated daily cycle of soil moisture and soil temperature. The analyses suggest that adding a photosynthesis based transpiration scheme such as the gas-exchange model can improve the ability of the land data assimilation system to simulate energy balance evaporation and transpiration under a range of soil and vegetation conditions and will benefit weather and climate land surface hydrology community modeling. Accurately capturing that moisture transport under diverse conditions helps improve capabilities to forecast a range of scenarios and processes such as droughts and regional climate.
Kumar, A., Chen, F., Niyogi, D., Alfieri, J. G., Ek M., and Mitchell, K. 2011. “Evaluation of a Photosynthesis-Based Canopy Resistance Formulation in the Noah Land-Surface Model,” Boundary-Layer Meteorology 138, 263–284, DOI 10.1007/s10546-010-9559-z.