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Geoscientific Model Development An interactive open-access journal of the European Geosciences Union
Geosci. Model Dev., 9, 1959-1976, 2016
https://doi.org/10.5194/gmd-9-1959-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Development and technical paper
27 May 2016
Sensitivity of biogenic volatile organic compounds to land surface parameterizations and vegetation distributions in California
Chun Zhao1, Maoyi Huang1, Jerome D. Fast1, Larry K. Berg1, Yun Qian1, Alex Guenther2, Dasa Gu2, Manish Shrivastava1, Ying Liu1, Stacy Walters3, Gabriele Pfister3, Jiming Jin4, John E. Shilling1, and Carsten Warneke5,6 1Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland, WA, USA
2Department of Earth System Science, University of California, Irvine, CA, USA
3National Center for Atmospheric Research, Boulder, CO, USA
4Departments of Watershed Sciences and Plants, Soils, and Climate, Utah State University, Logan, UT, USA
5National Oceanic and Atmospheric Administration, Earth System Research Laboratory, Boulder, CO, USA
6CIRES, University of Colorado, Boulder, CO, USA
Abstract. Current climate models still have large uncertainties in estimating biogenic trace gases, which can significantly affect atmospheric chemistry and secondary aerosol formation that ultimately influences air quality and aerosol radiative forcing. These uncertainties result from many factors, including uncertainties in land surface processes and specification of vegetation types, both of which can affect the simulated near-surface fluxes of biogenic volatile organic compounds (BVOCs). In this study, the latest version of Model of Emissions of Gases and Aerosols from Nature (MEGAN v2.1) is coupled within the land surface scheme CLM4 (Community Land Model version 4.0) in the Weather Research and Forecasting model with chemistry (WRF-Chem). In this implementation, MEGAN v2.1 shares a consistent vegetation map with CLM4 for estimating BVOC emissions. This is unlike MEGAN v2.0 in the public version of WRF-Chem that uses a stand-alone vegetation map that differs from what is used by land surface schemes. This improved modeling framework is used to investigate the impact of two land surface schemes, CLM4 and Noah, on BVOCs and examine the sensitivity of BVOCs to vegetation distributions in California. The measurements collected during the Carbonaceous Aerosol and Radiative Effects Study (CARES) and the California Nexus of Air Quality and Climate Experiment (CalNex) conducted in June of 2010 provided an opportunity to evaluate the simulated BVOCs. Sensitivity experiments show that land surface schemes do influence the simulated BVOCs, but the impact is much smaller than that of vegetation distributions. This study indicates that more effort is needed to obtain the most appropriate and accurate land cover data sets for climate and air quality models in terms of simulating BVOCs, oxidant chemistry and, consequently, secondary organic aerosol formation.

Citation: Zhao, C., Huang, M., Fast, J. D., Berg, L. K., Qian, Y., Guenther, A., Gu, D., Shrivastava, M., Liu, Y., Walters, S., Pfister, G., Jin, J., Shilling, J. E., and Warneke, C.: Sensitivity of biogenic volatile organic compounds to land surface parameterizations and vegetation distributions in California, Geosci. Model Dev., 9, 1959-1976, https://doi.org/10.5194/gmd-9-1959-2016, 2016.
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In this study, the latest version of MEGAN is coupled within CLM4 in WRF-Chem. In this implementation, MEGAN shares a consistent vegetation map with CLM4. This improved modeling framework is used to investigate the impact of two land surface schemes on BVOCs and examine the sensitivity of BVOCs to vegetation distributions in California. This study indicates that more effort is needed to obtain the most appropriate and accurate land cover data sets for climate and air quality models.
In this study, the latest version of MEGAN is coupled within CLM4 in WRF-Chem. In this...
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