Supplementary code for "Effect of Uncertainty in Water Vapor Continuum Absorption on CO2 Forcing, Longwave Feedback, and Climate Sensitivity"

This directory contains the code needed to reproduce the findings and figures of "Effect of Uncertainty in Water Vapor Continuum Absorption on CO2 Forcing, Longwave Feedback, and Climate Sensitivity".

To reproduce the data published with the manuscript:

spectral_olr.nc:

• unzip modified_continuum_input_files_single_constraint.zip and modified_continuum_input_files_general_constraint.zip in the folder arts-cat-data/model/mt_ckd_4.0/
• calculate spectral OLR using konrad and ARTS for different experiments (run_konrad_continuum.py). The variables are the continuum input file, and surface temperature to calculate the spectral longwave feedback, as well as perturbations of the surface temperature (+/- 1K) to calculate the surface/atmospheric feedback, and of the CO2 concentration (doubling) to calculate the radiative forcing.
• reformat and save data (convert_data.py)

opacity_emission_level.nc:

• calculate the optical depth of each vertical layer and each considered absorption species for different surface temperatures (calc_optical_depth.py)
• vertically integrate optical depth (integrate_optical_depth.py)
• calculate the emission level for each temperature (calc_emission_level.py)
• merge the emission levels into one array (merge_emission_level.py)
• reformat and save data (convert_data.py)

continuum_reference_conditions.nc

• calculate absorption coefficient (proportional to optical depth) for reference conditions and save them (calc_abs_coef.py)
• reformat and save data (convert_data.py)

continuum_all_profiles.nc

• calculate absorption coefficient for all atmospheric profiles and save them (rescale_continuum_general_constraint.py)
• reformat and save data (convert_data.py)

modified_continuum_input_files_single_constraint.zip and modified_continuum_input_files_general_constraint.zip

• read original data on self and foreign continuum from MT_CKD 4.0 and scale them (rescale_continuum_single_constraint.py and rescale_continuum_general_constraint.py)
• the modified continuum files have to be located in the folder arts-cat-data/model/mt_ckd_4.0/ to run run_konrad_continuum.py

tau_column.nc and tau_profile.nc

• calculate the optical depth of each vertical layer and each considered absorption species for different surface temperatures (calc_optical_depth.py)
• reformat and save data (convert_data.py)

To reproduce the figures:

Figure 1 & 2:

• calculate the absorption cross-section of the self continuum (calc_cross_section.py)
• plot opacity and cross sections (plot_Fig1_Fig2.py)

Figure 3:

• take/calculate scaling factor from files (continuum_all_profiles.nc and continuum_reference_conditions.nc)
• plot scaling factors (plot_Fig3.py)

Figure 4 & 5:

• calculate spectrally resolved and integrated feedbacks, forcing and plot them (plot_Fig4_5.py)

Figure 6:

• calculate emission fraction (calc_emission_fraction.py)
• read opacity, emission fraction, spectral OLR, and spectral feedbacks and plot them (plot_Fig6.py)

Figure 7:

• take column-integrated opacity from file (tau_column.nc) and plot (plot_Fig7.py)

Figure 8:

• take spectral olr (spectral_olr.nc), emission levels (opacity_emission_level.nc), and opacity profiles (tau_profile.nc) from respective files
• take MT_CKD data from input files (arts-cat-data/model/mt_ckd_4.0/H2O.xml)
• plot changes in opacity, spectral OLR, and temperature exponent of self continuum (plot_Fig8.py)

Figure A1:

• create atmosphere with C-shaped RH profile and plot (plot_FigA1.py)

Figure A2:

• read spectral OLR from file (spectral_olr.nc)
• calculate forcing, feedback, and climate sensitivity for both uniform and C-shaped profile, as well as for different choices of q_0 and plot them (plot_FigA2.py)