2024/12/18 by Michael P. Vermeuel, Dylan B. Millet, Delphine K. Farmer +13 · 1 voice · 4 citations
Agricultural and Biological Sciences · Chemistry · Earth and Planetary Sciences · #Atmospheric Ozone and Climate #Atmospheric chemistry #Atmospheric chemistry and aerosols #Atmospheric sciences #Canopy #Chemical transport model #Chemistry #Deposition (geology) #Ecology #Ecosystem #Environmental science #Flux (metallurgy) #Geography #Geology #Irradiance #Meteorology #Ozone #Physics #Plant responses to elevated CO2 #Sink (geography) #Temperate climate #Temperate forest #Temperate rainforest #Tree canopy #Troposphere
paper · pdf · doi:10.1029/2024jd042092
published in Journal of Geophysical Research Atmospheres 129(24) (American Geophysical Union)
openalex publication_date 2024/12/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
Abstract Dry deposition is the second largest tropospheric ozone (O 3 ) sink and occurs through stomatal and nonstomatal pathways. Current O 3 uptake predictions are limited by the simplistic big‐leaf schemes commonly used in chemical transport models (CTMs) to parameterize deposition. Such schemes fail to reproduce observed O 3 fluxes over terrestrial ecosystems, highlighting the need for more realistic treatment of surface‐atmosphere exchange in CTMs. We address this need by linking a resolved canopy model (1D Multi‐Layer Canopy CHemistry and Exchange Model, MLC‐CHEM) to the GEOS‐Chem CTM and use this new framework to simulate O 3 fluxes over three north temperate forests. We compare results with in situ measurements from four field studies and with standalone, observationally constrained MLC‐CHEM runs to test current knowledge of O 3 deposition and its drivers. We show that GEOS‐Chem overpredicts observed O 3 fluxes across all four studies by up to 2×, whereas the resolved‐canopy models capture observed diel profiles of O 3 deposition and in‐canopy concentrations to within 10%. Relative humidity and solar irradiance are strong O 3 flux drivers over these forests, and uncertainties in those fields provide the largest remaining source of model deposition biases. Flux partitioning analysis shows that: (a) nonstomatal loss accounts for 60% of O 3 deposition on average; (b) in‐canopy chemistry makes only a small contribution to total O 3 fluxes; and (c) the CTM big‐leaf treatment overestimates O 3 ‐driven stomatal loss and plant phytotoxicity in these temperate forests by up to 7×. Results motivate the application of fully online vertically explicit canopy schemes in CTMs for improved O 3 predictions.