This repository contains time series of annual-mean globally-averaged variables from various CMIP6 experiments, together with analysis of climate sensitivities, forcing and feedbacks.
Anomalies are calculated by subtracting the trend in piControl calculated over the time period parallel to the perturbation experiment, as in Andrews et al. (2012) and Forster et al. (2013). The final column is the multimodel mean.
| filename | description |
|---|---|
delta_tas_abrupt-4xCO2_cmip6.csv |
anomalies in surface air temperature [tas] relative to piControl in the abrupt-4xCO2 experiment |
delta_net_abrupt-4xCO2_cmip6.csv |
anomalies in net top-of-atmosphere flux [rsdt - rsut - rlut], relative to piControl in the abrupt-4xCO2 experiment |
delta_tas_1pctCO2_cmip6.csv |
anomalies in surface air temperature [tas] relative to piControl in the 1pctCO2 experiment |
delta_variable_experimentid_cmip6.csv |
anomalies in variable relative to piControl in the experimentid experiment |
gregory_plot_cmip6.csv
Linear regression of anomaly in net top-of-atmosphere flux vs. anomaly in surface air temperature over the first 150 years of the abrupt-4xCO2 experiment, following Gregory et al. (2004). gregory_plot_cmip6.txt contains the same information in a plain text file.
gregory_plot_fast_cmip6.csv and gregory_plot_slow_cmip6.csv
As for the standard Gregory plot but using years 1-20 (fast) and years 21-150 (slow) of the abrupt-4xCO2 experiment respectively, following Andrews et al. (2015)
| parameter | description | units |
|---|---|---|
| Model | CMIP6 Source ID | |
| F4x | 4xCO2 forcing (intercept) | W m-2 |
| lambda | climate feedback (slope) | W m-2 K-1 |
| ECS | effective climate sensitivity | K |
| FSW, FLW | shortwave and longwave components of F4x | W m-2 |
| lambdaSW, lambdaLW | shortwave and longwave components of lambda | W m-2 K-1 |
tcr_cmip6.csv
The transient climate response (TCR), derived from the 1pctCO2 experiment.
| parameter | description | units |
|---|---|---|
| TCR | tas anomaly averaged over years 61-80 | K |
| T140 | tas anomaly averaged over years 131-150 | K |
| ratio | T140 / TCR | unitless |
ohue_cmip6.csv
Linear regression of anomaly in net top-of-atmosphere flux vs. anomaly in surface air temperature in the 1pctCO2 experiment, following Gregory and Mitchell (1997). The slope of the regression line is the ocean heat uptake efficiency (OHUE, kappa).
| parameter | description | units |
|---|---|---|
| kappa_01_70 | OHUE calculated over years 1-70 | W m-2 K-1 |
| kappa_71_140 | OHUE calculated over years 71-140 | W m-2 K-1 |
two_layer_cmip6.csv
Fit to the two-layer model of the surface air temperature anomalies in the abrupt-4xCO2 experiment using the method described in Geoffroy et al. (2013).
| parameter | description | units |
|---|---|---|
| tau_f | fast (mixed layer) timescale | years |
| tau_s | slow (deep ocean) timescale | years |
| gamma | transfer co-efficient | W m-2 K-1 |
| C | mixed-layer heat capacity | W m-2 K-1 yrs |
| C_O | deep-ocean heat capacity | W m-2 K-1 yrs |
| a_f | contribution to delta_tas from the fast mode | unitless |
| a_s | contribution to delta_tas from the slow mode, 1 - a_f | unitless |
ecs_cmip6_cmip5.png and tcr_cmip6_cmip5.png
Standard box plots (median, interquartile range, max, min) with ensemble mean shown as dashed line and individual models shown as open circles. The IPCC AR5 likely (17 - 83%) range is shown for reference.
I acknowledge the World Climate Research Programme, which, through its Working Group on Coupled Modelling, coordinated and promoted CMIP6. I thank the climate modeling groups for producing and making available their model output, the Earth System Grid Federation (ESGF) for archiving the data and providing access, and the multiple funding agencies who support CMIP6 and ESGF.
This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
