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<p>The deposition of ozone to seawater is an important ozone sink. Despite constituting as much as a third of the total ozone deposition, it receives significantly less attention than the deposition to terrestrial ecosystems. Models have typically calculated the deposition rate based on a resistance-in-series model with a uniform waterside resistance. This leads to models having an essentially uniform deposition velocity of approximately 0.05&thinsp;<span class="inline-formula">cm s⁻¹</span> to seawater, which is significantly higher than the limited observational dataset. Following from <span class="cit" id="xref_text.1"><a href="#bib1.bibx20">Luhar et al.</a> (<a href="#bib1.bibx20">2018</a>)</span> we include a representation of the oceanic deposition of ozone in the GEOS-Chem model of atmospheric chemistry and transport based on its reaction with sea-surface iodide. The updated scheme halves the calculated annual area-weighted mean deposition velocity to water from 0.0464&thinsp;<span class="inline-formula">cm s⁻¹</span> (25th and 75th percentiles of 0.0461&thinsp;<span class="inline-formula">cm s⁻¹</span> and 0.0471&thinsp;<span class="inline-formula">cm s⁻¹</span> respectively) to 0.0231&thinsp;<span class="inline-formula">cm s⁻¹</span> (25th and 75th percentiles of 0.0121&thinsp;<span class="inline-formula">cm s⁻¹</span> and 0.0303&thinsp;<span class="inline-formula">cm s⁻¹</span> respectively). The calculated ozone deposition velocity varies from 0.009&thinsp;<span class="inline-formula">cm s⁻¹</span> in polar waters to 0.040&thinsp;<span class="inline-formula">cm s⁻¹</span> at the tropics. This improves comparisons to observations. The variability is driven mainly by the temperature-dependent rate constant for the reaction between iodide and ozone, the temperature dependence of the solubility, and variations in the ocean iodide concentration. The calculated annual deposition flux of ozone to the ocean is reduced from 222 to 122&thinsp;<span class="inline-formula">Tg yr⁻¹</span>, and overall deposition of ozone to all surface types reduces from 862 to 758&thinsp;<span class="inline-formula">Tg yr⁻¹</span>. Tropospheric ozone burdens and global mean OH increase from 324 to 328&thinsp;<span class="inline-formula">Tg</span>, and from <span class="inline-formula">1.17×10⁶</span> to <span class="inline-formula">1.18×10⁶</span>&thinsp;<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M15" display="inline" overflow="scroll" dspmath="mathml"><mrow class="unit"><mi mathvariant="normal">molec</mi><mo>.</mo><mspace width="0.125em" linebreak="nobreak"/><msup><mi mathvariant="normal">cm</mi><mrow><mo>-</mo><mn mathvariant="normal">3</mn></mrow></msup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="60pt" height="13pt" class="svg-formula" dspmath="mathimg" md5hash="7854b764331245d44485e730375fecbe"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-20-4227-2020-ie00001.svg" width="60pt" height="13pt" src="acp-20-4227-2020-ie00001.png"/></svg:svg></span></span>, respectively. A total of 34&thinsp;% of surface grid boxes experience a 10&thinsp;% or greater increase in ozone concentration. Comparisons between observations of surface ozone and the model are improved with the new parameterization notably around the Southern Ocean. Process-level representation of oceanic deposition of ozone thus appears essential for representing the concentration of surface ozone over the planet.</p>