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Climate drift in the CMIP3 models

Citation

Sen Gupta, A and Muir, LC and Brown, JN and Phipps, SJ and Durack, PJ and Monselesan, D and Wijffels, SE, Climate drift in the CMIP3 models, Journal of Climate, 25 pp. 4621-4640. ISSN 0894-8755 (2012) [Refereed Article]


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Copyright Statement

Copyright 2012 American Meteorological Society

DOI: doi:10.1175/JCLI-D-11-00312.1

Abstract

Even in the absence of external forcing, climate models often exhibit long-term trends that cannot be attributed to natural variability. This so-called climate drift arises for various reasons including the following: perturbations to the climate system on coupling component models together and deficiencies in model physics and numerics. When examining trends in historical or future climate simulations, it is important to know the error introduced by drift so that action can be taken where necessary. This study assesses the importance of drift for a number of climate properties at global and local scales. To illustrate this, the present paper focuses on simulated trends over the second half of the twentieth century. While drift in globally averaged surface properties is generally considerably smaller than observed and simulated twentieth-century trends, it can still introduce nontrivial errors in some models. Furthermore, errors become increasingly important at smaller scales. The direction of drift is not systematic across different models or variables, as such drift is considerably reduced in the multimodel mean. Despite drift being primarily associated with ocean adjustment, it is also apparent in atmospheric variables. For example, most models have local drift magnitudes in surface air and ocean temperatures that are typically between 15% and 35% of the twentieth-century simulation trend magnitudes for 19502000. Below depths of 10002000 m, drift dominates over any forced trend inmost regions. As such steric sea level is strongly affected and for some models and regions the sea level trend direction is reversed. Thus depending on the application, drift may be negligible or may make up an important part of the simulated trend.

Item Details

Item Type:Refereed Article
Keywords:climate models, drift, CMIP3
Research Division:Earth Sciences
Research Group:Atmospheric Sciences
Research Field:Climate Change Processes
Objective Division:Environment
Objective Group:Climate and Climate Change
Objective Field:Climate Change Models
Author:Phipps, SJ (Dr Steven Phipps)
ID Code:104715
Year Published:2012
Web of Science® Times Cited:49
Deposited By:IMAS Research and Education Centre
Deposited On:2015-11-18
Last Modified:2017-10-30
Downloads:91 View Download Statistics

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