Exploring the drivers of tropospheric hydroxyl radical trends in the Geophysical Fluid Dynamics Laboratory AM4.1 atmospheric chemistry–climate model

We explore the sensitivity of modeled tropospheric hydroxyl (OH) concentration trends to meteorology and near-term climate forcers (NTCFs), namely methane (CH 4 ) nitrogen oxides ( NO x = NO 2 + NO ) <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="93pt" height="13p...

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Bibliographic Details
Published in:Atmospheric Chemistry and Physics
Main Authors: Chua, Glen, Naik, Vaishali, Horowitz, Larry Wayne
Format: Text
Language:English
Published: 2023
Subjects:
Sea ice
Online Access:https://doi.org/10.5194/acp-23-4955-2023
https://acp.copernicus.org/articles/23/4955/2023/
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Summary:We explore the sensitivity of modeled tropospheric hydroxyl (OH) concentration trends to meteorology and near-term climate forcers (NTCFs), namely methane (CH 4 ) nitrogen oxides ( NO x = NO 2 + NO ) <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="93pt" height="13pt" class="svg-formula" dspmath="mathimg" md5hash="1740a284ba68bb05139a5d17b881f526"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-23-4955-2023-ie00001.svg" width="93pt" height="13pt" src="acp-23-4955-2023-ie00001.png"/></svg:svg> carbon monoxide (CO), non-methane volatile organic compounds (NMVOCs) and ozone-depleting substances (ODSs), using the Geophysical Fluid Dynamics Laboratory (GFDL)'s atmospheric chemistry–climate model, the Atmospheric Model version 4.1 (AM4.1), driven by emissions inventories developed for the Sixth Coupled Model Intercomparison Project (CMIP6) and forced by observed sea surface temperatures and sea ice prepared in support of the CMIP6 Atmospheric Model Intercomparison Project (AMIP) simulations. We find that the modeled tropospheric air-mass-weighted mean [OH] has increased by ∼5 % globally from 1980 to 2014. We find that NO x emissions and CH 4 concentrations dominate the modeled global trend, while CO emissions and meteorology were also important in driving regional trends. Modeled tropospheric NO 2 column trends are largely consistent with those retrieved from the Ozone Monitoring Instrument (OMI) satellite, but simulated CO column trends generally overestimate those retrieved from the Measurements of Pollution in The Troposphere (MOPITT) satellite, possibly reflecting biases in input anthropogenic emission inventories, especially over China and South Asia.

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