Isoprene Emission Response to Drought and the Impact on Global Atmospheric Chemistry
Jiang, X., A. Guenther, M. Potosnak, Chris Geron, R. Seco, T. Karl, S. Kim, L. Gu, AND S. Pallardy. Isoprene Emission Response to Drought and the Impact on Global Atmospheric Chemistry. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 183:69-83:Erratum 185:272-273, (2018).
Biogenic volatile organic compounds (BVOCs) emitted from terrestrial ecosystems play a very important role in atmospheric chemistry. Thousands of BVOCs have been characterized, and there is growing evidence that many more remain to be identified. Biogenic isoprene emission, one of the key identified BVOCs, is emitted in large quantities by vegetation. Global estimation of biogenic isoprene emission is 440-600 TgC per year, about half of the total BVOC emission. This isoprene emission is 5 time greater than total anthropogenic emission of all VOC, and in addition, isoprene is much more reactive than anthropogenic VOC, and therefore has a large global impact on aerosol, ozone, and climate via reaction with OH radical. The drought impacts discussed here have significant impacts on isoprene emission globally, ranging from a 10% increase under mild drought to 20% decrease under severe drought.
Biogenic isoprene emissions play a very important role in atmospheric chemistry. They are strongly dependent on various environmental conditions, such as temperature, solar radiation, plant water stress, ambient ozone and CO2 concentrations, and soil moisture. Current biogenic emission models (i.e. Model of Emissions of Gases and Aerosols from Nature, MEGAN) can simulate emission responses to some of the major driving variables, such as short-term variations in temperature and solar radiation, but the other factors are either missing or poorly represented. In this paper we propose a new modeling approach that considers the physiological effects of drought stress on plant photosynthesis and isoprene emissions for use in the MEGAN3 biogenic emission model.
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Organization:U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
NATIONAL RISK MANAGEMENT RESEARCH LABORATORY
AIR AND ENERGY MANAGEMENT DIVISION
ENERGY AND NATURAL SYSTEMS BRANCH