Constraining climate model properties using optimal fingerprint detection methods

Chris Forest, M. R. Allen, A. P. Sokolov, P. H. Stone

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

We present a method for constraining key properties of the climate system that are important for climate prediction (climate sensitivity and rate of heat penetration into the deep ocean) by comparing a model's response to known forcings over the twentieth century against climate observations for that period. We use the MIT 2D climate model in conjunction with results from the Hadley Centre's coupled atmosphere-ocean general circulation model (AOGCM) to determine these constraints. The MIT 2D model, which is a zonally averaged version of a 3D GCM, can accurately reproduce the global-mean transient response of coupled AOGCMs through appropriate choices of the climate sensitivity and the effective rate of diffusion of heat anomalies into the deep ocean. Vertical patterns of zonal mean temperature change through the troposphere and lower stratosphere also compare favorably with those generated by 3-D GCMs. We compare the height-latitude pattern of temperature changes as simulated by the MIT 2D model with observed changes, using optimal finger-print detection statistics. Using a linear regression model as in Allen and Tett this approach yields an objective measure of model-observation goodness-of-fit (via the residual sum of squares weighted by differences expected due to internal variability). The MIT model permits one to systematically vary the model's climate sensitivity (by varying the strength of the cloud feedback) and rate of mixing of heat into the deep ocean and determine how the goodness-of-fit with observations depends on these factors. This provides an efficient framework for interpreting detection and attribution results in physical terms. With aerosol forcing set in the middle of the IPCC range, two sets of model parameters are rejected as being implausible when the model response is compared with observations. The first set corresponds to high climate sensitivity and slow heat uptake by the deep ocean. The second set corresponds to low sensitivities for all magnitudes of heat uptake. These results demonstrate that fingerprint patterns must be carefully chosen, if their detection is to reduce the uncertainty of physically important model parameters which affect projections of climate change.

Original languageEnglish (US)
Pages (from-to)277-295
Number of pages19
JournalClimate Dynamics
Volume18
Issue number3-4
DOIs
StatePublished - Dec 1 2001

Fingerprint

detection method
climate modeling
climate
ocean
general circulation model
climate prediction
twentieth century
stratosphere
troposphere
penetration
temperature
aerosol
anomaly
climate change
atmosphere

All Science Journal Classification (ASJC) codes

  • Atmospheric Science

Cite this

Forest, Chris ; Allen, M. R. ; Sokolov, A. P. ; Stone, P. H. / Constraining climate model properties using optimal fingerprint detection methods. In: Climate Dynamics. 2001 ; Vol. 18, No. 3-4. pp. 277-295.
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Constraining climate model properties using optimal fingerprint detection methods. / Forest, Chris; Allen, M. R.; Sokolov, A. P.; Stone, P. H.

In: Climate Dynamics, Vol. 18, No. 3-4, 01.12.2001, p. 277-295.

Research output: Contribution to journalArticle

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