Analysis code and data for FF CO2

This folder provides the data and code necessary to reproduce the main findings of the manuscript. The code includes both NCL (NCAR Command Language) and MATLAB scripts. Data processing is mainly performed using NCL, while MATLAB is used to plot the ternary diagram in Figure 3. The version of NCL used is 6.6.2, and the version of MATLAB is R2022b. Introduction to each directorydata: Contains the basic data required to run the code, as well as the data generated after execution.scripts: Contains the code required for data processing and plotting.CCGCRV: Includes code for a curve fitting method that is incorporated in a standard software package provided by NOAA Earth System Research Laboratories (https://gml.noaa.gov/aftp/user/thoning/ccgcrv/). Introduction to using the scripts: Figure 1:BRW_MLO_seasonal_index.ncl: Calculate SCA, SZC, and AZC at BRW and MLOBRW_MLO_SCA_trend.ncl, BRW_MLO_SZC_trend.ncl, BRW_MLO_AZC_trend.ncl: Calculate trends in SCA, SZC, and AZC at BRW and MLOFigure 1 was plotted using Origin 2022, based on data calculated from the NCL scripts above. Figure 2:Gridded_SCA_trend_HIS_Base.ncl: Calculated the gridded SCA trend in the Northern Hemisphere from the HIS_Base experiment.The other NCL scripts starting with "Gridded" serve similar purposes, but the parameters calculated, time periods, and control experiments differ.Fig2_SCA_SZC_AZC_trend_His_CMIP6.ncl: The script for plotting Figure 2. Figure 3:Fig3_contribution.m: Quantitatively characterize the contributions of fossil fuel emissions, terrestrial CO2 fluxes, and oceanic CO2 fluxes to the trends in the CO2 seasonal parameters, and plot a ternary diagram.multiVarMapTri.m, tight_subplot.m: Subroutines required for plotting. Other notes:Since the CO2 concentration data simulated by GEOS-Chem are very large in volume, we only provide the simulation results of the HIS_Base experiment for the year 1979 as an example here. Other data are available from the corresponding author upon reasonable request.