Identification

Title

The role of isotope‐enabled GCM complexity in simulating tropical circulation changes in high‐CO2 scenarios

Abstract

Stable water isotopes are data-rich tracers of the hydrological cycle, and, recently, the advent of isotope-enabled climate models has allowed for investigations into the utility of water isotopes for tracking changes in the large-scale atmospheric circulation. Among the suite of published isotope-enabled climate models, those with intermediate complexity offer the benefits of efficiency, allowing for long ensemble runs. However, the ability of these models to simulate the response to global warming with the same fidelity as state-of-the-art models is questionable. Here we evaluate an intermediate complexity model, SPEEDY-IER, in a high-CO(2)scenario and compare its performance to an Intergovernmental Panel on Climate Change (IPCC)-class model, iCAM5. SPEEDY-IER can generally simulate changes in tropical circulation, the weakening of the Walker circulation, and the narrowing of the deep tropics. A deeper investigation of water isotope fields indicates SPEEDY-IER simulates qualitative trends in precipitation and vapor isotopes with fidelity, but it does not simulate amplitudes or spatial patterns of water isotope changes shown in iCAM5. This bias in SPEEDY-IER is mainly due to its coarse resolution and simplified convection scheme. We then modify the model by introducing condensation and detrainment in intermediate convection levels; this modification successfully improves SPEEDY-IER's simulation of water isotope fields, though the response of the Walker circulation to climate change is weakened. We demonstrate that evaluating water isotope fields reveals hidden biases in a climate model and guides improvements to the model's performance. Thus, the examination of water isotope fields and validation against available observations likely provides more stringent constraints for model physics.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d7833w9k

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

North bounding latitude

South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2020-08-18T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

Data format

name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact