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The impact of model resolution on ozone simulation

As higher resolution models will be needed in the future for various studies and predictions, the change in model performance due to changes in the resolution itself should be better understood. This study is aiming to understand the impact of increased model resolution on the tropospheric ozone simulation, and to what degree the increased model resolution can mitigate the biases in the models. Using GEOS-Chem v11-01, two full chemistry runs with different horizontal resolution (4° x 5° and 2° x 2.5°) have been conducted. Around the Upper Troposphere and Lower Stratosphere (UTLS) region, where the stratosphere-troposphere-exchange (STE) occurs, ozone concentration increases in the polar region, whereas decreases in the lower latitudes in the 2° x 2.5° run, about 10% difference. The difference in the lower troposphere is about 10% as well. The global budget of tropospheric ozone has been investigated. This budget is governed by the influx from the stratosphere, ozone dry deposition near the surface, and tropospheric ozone chemical production and destruction. The calculated tropospheric ozone burden is about 350 Tg in the 4° x 5° run, and about 330 Tg in the 2° x 2.5° run. The differences in dry deposition, production and loss rate are within 5%.