README.md

CH4-CO-OH BoxModel

README file for the 2-box model from Nguyen et al.

• Originally used and created by Alex Turner for Turner et al, 2017
• Modifications made by Newton Nguyen, Alex Turner, and Christian Frankenberg for Nguyen et al, 2020

February 14, 2020

Info

This code models the interactive methane, carbon monoxide, and hydroxyl chemistry in Earth's atmosphere, which was used in Nguyen et al, 2020. There are two tropospheric boxes and to optional stratospheric boxes. The simplified tropospheric chemistry is from Prather 1994. The original model was used in Turner et al, 2017.

Code Overview

• We have included all the tests seen in Nguyen et al, 2020 (Refer to below table)
• The MATLAB code can be run using the "DriverScript.m" file.
• The inversions use publicly available datasets. As such, we have not included those datasets in our tarball.
• We have included scripts to download all of the datasets though. This can be done by running the "download_data.csh" script.
• Users could also manually download the data by navigating the websites (see below), contacting the PIs for those datasets, contacting Newton Nguyen ([email protected]), Alex Turner ([email protected]), or Christian Frankenberg ([email protected]).
• The code will still run without the original datasets and will just use the hemispheric averages that were bootstrapped from Turner et al.

Public datasets:

• CH4 from NOAA/ESRL
• PI: Ed Dlugokencky
• URL: "ftp://aftp.cmdl.noaa.gov/data/trace_gases/ch4/flask/"
• MCF from NOAA/ESRL
• PI: Steve Montzka
• URL: "ftp://aftp.cmdl.noaa.gov/data/hats/solvents/CH3CCl3/"
• MCF from GAGE/AGAGE
• PI: Ron Prinn
• URL: "http://agage.mit.edu/"
• CH4C13 from NOAA/ESRL
• PI: James White
• URL: "ftp://aftp.cmdl.noaa.gov/data/trace_gases/ch4c13/flask/"
• CH4C13 from U. Heidelberg
• PI: Ingeborg Levin
• URL: "http://www.iup.uni-heidelberg.de/institut/forschung/groups/kk/Data_html"
• CH4C13 from U. Washington
• Data is included in the tarball
• CH4C13 (MCF) from UC Irvine
• Data is included in the tarball
• C2H6 data (wrote an observation operator but did not use in the manuscript)
• URL: "http://ds.data.jma.go.jp/gmd/wdcgg/cgi-bin/wdcgg/download.cgi?para=VOCs"

Table 1: Tests Scripts

Test Description	Corresponding figure in Nguyen et al	File Name
Test instantaneous 10-Tg-perturbation lifetime	Fig. 1A	ForwardModelTest.m
Forward model runs to test equilibrium concentrations	Fig. 1B, C	SteadyStateTest.m
El Nino Biomass Burning perturbation tests	Fig. 2	SyntheticEnso.m
Idealized inversion with synthetic concentrations	Fig. 3	SyntheticInversion.m
Inversions constrained by Observations	Fig. 4	DriverScriptCaseI.m

Table 2: Inversions from Fig. 4 of Nguyen et al

Please refer to Tables 1 and A1 in Nguyen et al.

Case	File Name
-I +[OH]	DriverScript.m
-I	DriverScriptCase1.m
+I	DriverScriptCase2.m
+I +SCO	DriverScriptCase3.m
+I +SOH	DriverScriptCase4.m
+I +SOH +SCO	DriverScriptCase5.m

Citations

• Nguyen, Newton H., Alexander J. Turner, Yi Yin, Michael J. Prather, and Christian Frankenberg. “Effects of Chemical Feedbacks on Decadal Methane Emissions Estimates.” Geophysical Research Letters 47, no. 3 (2020): e2019GL085706. https://doi.org/10.1029/2019GL085706.
• Turner, Alexander J., Christian Frankenberg, Paul O. Wennberg, and Daniel J. Jacob. “Ambiguity in the Causes for Decadal Trends in Atmospheric Methane and Hydroxyl.” Proceedings of the National Academy of Sciences, April 12, 2017, 201616020. https://doi.org/10.1073/pnas.1616020114.
• Prather, Michael J. “Lifetimes and Eigenstates in Atmospheric Chemistry.” Geophysical Research Letters 21, no. 9 (May 1994): 801–4. https://doi.org/10.1029/94GL00840.