DOI: 10.5061/dryad.kh18932b3
title: Comparison between ozone column depths and methane lifetimes computed by 1-D and 3-D models at different atmospheric O2 Levels

description: Recently, Cooke et al. (2022) used a 3-D coupled chemistry-climate model
 (WACCM6) to calculate ozone column depths at varied atmospheric O2 levels.
 They argued that previous 1-D photochemical model studies, e.g., Segura et
 al. (2003), may have overestimated the ozone column depth at low pO2, and
 hence also overestimated the lifetime of methane. We have compared new
 simulations from an updated version of the Segura et al. model with those
 from WACCM6, together with some results from another 1-D and 3-D model.
 The discrepancy in ozone column depths is likely due to multiple
 interacting parameters, including lower boundary conditions, vertical and
 meridional transport rates, and different chemical mechanisms, especially
 the treatment of O2 photolysis in the Schumann-Runge (SR) bands (175-205
 nm). The discrepancy in tropospheric OH concentrations and methane
 lifetime between WACCM6 and the 1-D model at low pO2 is reduced when
 absorption from CO2 and H2O in this wavelength region is included in
 WACCM6. Including scattering in the SR bands may further reduce this
 difference. Resolving these issues can be accomplished by developing an
 accurate parameterization for O2 photolysis in the SR bands and then
 repeating these calculations in the various models. Work is already
 underway to this end.
description: We have data from three different models: 1-D photochemical
 model, WACCM6 3D model, and ROCKE-3D model. All models have been run with
 4 different atmospheric O2 levels: 1 PAL, 0.1 PAL, 0.01 PAL, and 0.001
 PAL. The source code for the 1-D photochemical model from Kasting group is
 available on Github: https://github.com/AoshuangJi/1-D-photochemical-model. The specific release for WACCM6 used in this paper is CESM2.1.3, which can be downloaded from the following: https://escomp.github.io/CESM/versions/cesm2.1/html/downloading_cesm. The source code for ROCKE-3D model is available through: https://simplex.giss.nasa.gov/gcm/ROCKE-3D/. The data for generating Figure 1 are saved in Table 1 in our manuscript. All the data from the 1D photochemical model are in Standard 1DnoCL.zip and seperate files with '1D' in the filename. Especially, the dataset 'Figure5_1D.csv' is from the 1D photochemical model by running one step from standard run with different solar zenith angles at the present atmosphere. The datasets 'Figure5_LBL.csv' is from Fernandez et al. (2007): https://doi.org/10.1016/j.jqsrt.2006.08.005. The data was recovered using webPlotDigitizer (https://automeris.io/WebPlotDigitizer/). We also use this tool for plotting the ozone column depths from Jaziri et al. (2022): https://doi.org/10.5194/cp-18-2421-2022. All the data from the WACCM6 3D model are under WACCM6.zip. All the data from the ROCKE 3D model are in a single file, named as 'ROCKE3D.nc'. 
description: The data can be downloaded and processed using MatLab. The MatLab
 code 'plotdata.m' to read data and plot all the figures is also
 uploaded here. The pathway to read data in the code should be adjusted to
 where readers save those data. More detailed information can be found in
 'README.md'. We have three different models.
 Files that contain '1D' in the file name are outputs from the
 1-D photochemical model. The .zip file 'Standard1DnoCL.zip'
 includes outputs from Standard 1D model without chlorine at four different
 pO2 levels. To replicate those runs, one can adjust the chlorine Flag
 'CLFLAG' in '/1DModelAoshuangJi/IO/input_atmchem.dat'
 to '1', and follow the instruction note on Github (see the link
 below). There are 'Converged' runs and 'ONESTEP' runs.
 All the important information can be found in files that contains
 'outchem'. The data used for plotting are saved in /plot and
 have 'OUTPUT_PLOT' in the file name. 'NOS' indicates
 outputs from 1D runs without scattering, and 'NOSNOA' indicates
 without absorption by H2O/CO2. The sepearte 1D files '.csv' are
 specified for each figure. All the ouputs from WACCM6
 are saved in 'WACCM6.zip'. Seperate files like
 'PI_j_mr_T_Z3_data_IC.csv' save most of the outputs for plotting
 from WACCM6. 'PI' means pre-industry, 'Ten' means 10%
 PAL pO2, 'One' means 1% PAL pO2, and 'Zero1' means
 0.1% PAL pO2. 'ROCKED3D.nc' contains all the
 data from ROCKE-3D model.