Datasets used in Bacmeister et al, JAMES (2020). " CO2 increase experiments ..."

Datasets used in the creation of original figures of Bacmeister et al. JAMES (2020). CO2 increase experiments using the Community Earth System Model (CESM): Relationship to climate sensitivity and comparison of CESM1 to CESM2.

We examine the response of the Community Earth System Model versions 1 and 2 (CESM1 and CESM2) to abrupt quadrupling of atmospheric CO2 concentrations (4xCO2) and to 1% annually increasing CO2 concentrations (1%CO2). Different estimates of equilibrium climate sensitivity (ECS) for CESM1 and CESM2 are presented. All estimates show that the sensitivity of CESM2 has increased by 1.5K or more over that of CESM1. At the same time the transient climate response (TCR) of CESM1 and CESM2 derived from 1%CO2 experiments has not changed significantly - 2.1K in CESM1 and 2.0K in CESM2. Increased initial forcing as well as stronger shortwave radiation feedbacks are responsible for the increase in ECS seen in CESM2. A decomposition of regional radiation feedbacks and their contribution to global feedbacks shows that the Southern Ocean plays a key role in the overall behavior of 4xCO2 experiments, accounting for about 50% of the total shortwave feedback in both CESM1 and CESM2. The Southern Ocean is also responsible for around half of the increase in shortwave feedback between CESM1 and CESM2, with a comparable contribution arising over tropical ocean. Experiments using a thermodynamic slab-ocean model (SOM) yield estimates of ECS that are in remarkable agreement with those from fully-coupled earth system model (ESM) experiments for the same level of CO2 increase. Finally, we show that the similarity of TCR in CESM1 and CESM2 masks significant regional differences in warming that occur in the 1%CO2 experiments for each model.

DOI

https://doi.org/10.5065/8406-p773

Spatial Resolution

1.0 degreesLatitude
1.0 degreesLongitude
2.0 degreesLatitude
2.0 degreesLongitude

Related Links

N/A

GCMD Science Keywords

• Atmosphere > Atmospheric Chemistry > Carbon And Hydrocarbon Compounds > Carbon Dioxide
• Models > Atmospheric General Circulation Models

File Media Types

• application/x-netcdf
• text/plain
• application/x-hdf

Support Contact

Cecile Hannay
UCAR/NCAR - Climate and Global Dynamics Laboratory
hannay@ucar.edu

Data Curator

GDEX Curator
UCAR/NCAR - GDEX
datahelp@ucar.edu

Legal Constraints

Creative Commons Attribution 4.0 International License.

Access Constraints

None

Full Metadata

DIF XML
ISO19139 XML
OAI DC
JSON-LD

Version History

1.0