TY - JOUR

T1 - FORCAsT-gs

T2 - Importance of Stomatal Conductance Parameterization to Estimated Ozone Deposition Velocity

AU - Otu-Larbi, F.

AU - Conte, A.

AU - Fares, S.

AU - Wild, O.

AU - Ashworth, K.

PY - 2021/9/30

Y1 - 2021/9/30

N2 - The role of stomata in regulating photosynthesis and transpiration, and hence governing global biogeochemical cycles and climate, is well-known. Less well-understood, however, is the importance of stomatal control to the exchange of other trace gases between terrestrial vegetation and the atmosphere. Yet these gases determine atmospheric composition, and hence air quality and climate, on scales ranging from local to global, and seconds to decades. Vegetation is a major sink for ground-level ozone via the process of dry deposition and the primary source of many biogenic volatile organic compounds (BVOCs). The rate of dry deposition is largely controlled by the rate of diffusion of a gas through the stomata, and this also governs the emission rate of some key BVOCs. It is critical therefore that canopy-atmosphere exchange models capture the physiological processes controlling stomatal conductance and the transfer of trace gases other than carbon dioxide and water vapor. We incorporate three of the most widely used coupled stomatal conductance-photosynthesis models into the one-dimensional multi-layer FORest Canopy-Atmosphere Transfer (FORCAsT1.0) model to assess the importance of choice of parameterization on simulated ozone deposition rates. Modeled GPP and stomatal conductance across a broad range of ecosystems differ by up to a factor of two between the best and worst performing model configurations. This leads to divergences in seasonal and diel profiles of ozone deposition velocity of up to 30% and deposition rate of up to 13%, demonstrating that the choice of stomatal conductance parameterization is critical in accurate quantification of ozone deposition.

AB - The role of stomata in regulating photosynthesis and transpiration, and hence governing global biogeochemical cycles and climate, is well-known. Less well-understood, however, is the importance of stomatal control to the exchange of other trace gases between terrestrial vegetation and the atmosphere. Yet these gases determine atmospheric composition, and hence air quality and climate, on scales ranging from local to global, and seconds to decades. Vegetation is a major sink for ground-level ozone via the process of dry deposition and the primary source of many biogenic volatile organic compounds (BVOCs). The rate of dry deposition is largely controlled by the rate of diffusion of a gas through the stomata, and this also governs the emission rate of some key BVOCs. It is critical therefore that canopy-atmosphere exchange models capture the physiological processes controlling stomatal conductance and the transfer of trace gases other than carbon dioxide and water vapor. We incorporate three of the most widely used coupled stomatal conductance-photosynthesis models into the one-dimensional multi-layer FORest Canopy-Atmosphere Transfer (FORCAsT1.0) model to assess the importance of choice of parameterization on simulated ozone deposition rates. Modeled GPP and stomatal conductance across a broad range of ecosystems differ by up to a factor of two between the best and worst performing model configurations. This leads to divergences in seasonal and diel profiles of ozone deposition velocity of up to 30% and deposition rate of up to 13%, demonstrating that the choice of stomatal conductance parameterization is critical in accurate quantification of ozone deposition.

KW - forest ecosystems

KW - gross primary productivity

KW - model parameterization

KW - ozone damage

KW - ozone deposition

KW - Stomatal conductance

KW - Air quality

KW - Biogeochemistry

KW - Carbon dioxide

KW - Deposition rates

KW - Ecosystems

KW - Forestry

KW - Ozone layer

KW - Parameterization

KW - Photosynthesis

KW - Physiological models

KW - Process control

KW - Vegetation

KW - Volatile organic compounds

KW - Biogenic volatile organic compounds

KW - Biogeochemical cycle

KW - Deposition velocities

KW - Dry deposition

KW - Forest ecosystem

KW - Gross primary productivity

KW - Model parameterization

KW - Ozone damage

KW - Trace gas

KW - Ozone

U2 - 10.1029/2021MS002581

DO - 10.1029/2021MS002581

M3 - Journal article

VL - 13

JO - Journal of Advances in Modeling Earth Systems

JF - Journal of Advances in Modeling Earth Systems

IS - 9

M1 - e2021MS002581

ER -