TY - JOUR

T1 - Impact of Drought on Isoprene Fluxes Assessed Using Field Data, Satellite-Based GLEAM Soil Moisture and HCHO Observations from OMI

AU - Opacka, Beata

AU - Müller, Jean-François

AU - Stavrakou, Trissevgeni

AU - Miralles, Diego G.

AU - Koppa, Akash

AU - Pagán, Brianna Rita

AU - Potosnak, Mark J.

AU - Seco, Roger

AU - De Smedt, Isabelle

AU - Guenther, Alex B.

N1 - Funding Information: This research was supported by the Belgian Science Policy Office (BELSPO) through the STEREO III project ALBERI (Assessing Links between Biogenic Emissions and Remotely sensed photosynthesis Indicators, contract no. SR/00/373, 2019-2021) and through the BRAIN-be 2.0 project EQUATOR (Emission Quantification of Atmospheric tracers in the Tropics using ObseRvations from satellites, contract no. B2/202/P1/EQUATOR, 2021-2025). A.B.G. was also supported by NASA ACMAP 80NSSC19K0986. R.S. was supported by grants RYC2020-029216-I and CEX2018-000794-S funded by the Ministerio de Ciencia e Innovaci?n (MCIN/AEI/10.13039/501100011033) and by the European Social Fund (ESF) through ?ESF Investing in your future?.provided us with valuable information about soil properties used in this study. Funding Information: Funding: This research was supported by the Belgian Science Policy Office (BELSPO) through the STEREO III project ALBERI (Assessing Links between Biogenic Emissions and Remotely sensed photosynthesis Indicators, contract no. SR/00/373, 2019-2021) and through the BRAIN-be 2.0 project EQUATOR (Emission Quantification of Atmospheric tracers in the Tropics using ObseRvations from satellites, contract no. B2/202/P1/EQUATOR, 2021-2025). A.B.G. was also supported by NASA ACMAP 80NSSC19K0986. R.S. was supported by grants RYC2020-029216-I and CEX2018-000794-S funded by the Ministerio de Ciencia e Innovación (MCIN/AEI/10.13039/501100011033) and by the European Social Fund (ESF) through “ESF Investing in your future”. Publisher Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland.

PY - 2022

Y1 - 2022

N2 - Biogenic volatile organic compounds (BVOCs), primarily emitted by terrestrial vegetation, are highly reactive and have large effects on the oxidizing potential of the troposphere, air quality and climate. In terms of global emissions, isoprene is the most important BVOC. Droughts bring about changes in the surface emission of biogenic hydrocarbons mainly because plants suffer water stress. Past studies report that the current parameterization in the state-of-the-art Model of Emissions of Gases and Aerosols from Nature (MEGAN) v2.1, which is a function of the soil water content and the permanent wilting point, fails at representing the strong reduction in isoprene emissions observed in field measurements conducted during a severe drought. Since the current algorithm was originally developed based on potted plants, in this study, we update the parameterization in the light of recent ecosystem-scale measurements of isoprene conducted during natural droughts in the central U.S. at the Missouri Ozarks AmeriFlux (MOFLUX) site. The updated parameterization results in stronger reductions in isoprene emissions. Evaluation using satellite formaldehyde (HCHO), a proxy for BVOC emissions, and a chemical-transport model, shows that the adjusted parameterization provides a better agreement between the modelled and observed HCHO temporal variability at local and regional scales in 2011–2012, even if it worsens the model agreement in a global, long-term evaluation. We discuss the limitations of the current parameterization, a function of highly uncertain soil properties such as porosity.

AB - Biogenic volatile organic compounds (BVOCs), primarily emitted by terrestrial vegetation, are highly reactive and have large effects on the oxidizing potential of the troposphere, air quality and climate. In terms of global emissions, isoprene is the most important BVOC. Droughts bring about changes in the surface emission of biogenic hydrocarbons mainly because plants suffer water stress. Past studies report that the current parameterization in the state-of-the-art Model of Emissions of Gases and Aerosols from Nature (MEGAN) v2.1, which is a function of the soil water content and the permanent wilting point, fails at representing the strong reduction in isoprene emissions observed in field measurements conducted during a severe drought. Since the current algorithm was originally developed based on potted plants, in this study, we update the parameterization in the light of recent ecosystem-scale measurements of isoprene conducted during natural droughts in the central U.S. at the Missouri Ozarks AmeriFlux (MOFLUX) site. The updated parameterization results in stronger reductions in isoprene emissions. Evaluation using satellite formaldehyde (HCHO), a proxy for BVOC emissions, and a chemical-transport model, shows that the adjusted parameterization provides a better agreement between the modelled and observed HCHO temporal variability at local and regional scales in 2011–2012, even if it worsens the model agreement in a global, long-term evaluation. We discuss the limitations of the current parameterization, a function of highly uncertain soil properties such as porosity.

KW - BVOCs

KW - drought

KW - formaldehyde

KW - GLEAM

KW - isoprene

KW - MEGAN

KW - Missouri

KW - OMI

KW - Ozarks

U2 - 10.3390/rs14092021

DO - 10.3390/rs14092021

M3 - Journal article

AN - SCOPUS:85129209509

VL - 14

JO - Remote Sensing

JF - Remote Sensing

SN - 2072-4292

IS - 9

M1 - 2021

ER -