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Exploring the impact of CMIP5 model biases on the simulation of North Atlantic decadal variability
Author(s) -
Menary Matthew B.,
Hodson Daniel L. R.,
Robson Jon I.,
Sutton Rowan T.,
Wood Richard A.,
Hunt Jonathan A.
Publication year - 2015
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2015gl064360
Subject(s) - ocean gyre , climatology , anomaly (physics) , environmental science , temperature salinity diagrams , climate model , ensemble average , data assimilation , coupled model intercomparison project , climate change , salinity , geology , oceanography , subtropics , meteorology , geography , ecology , physics , condensed matter physics , biology
Instrumental observations, paleoproxies, and climate models suggest significant decadal variability within the North Atlantic subpolar gyre (NASPG). However, a poorly sampled observational record and a diversity of model behaviors mean that the precise nature and mechanisms of this variability are unclear. Here we analyze an exceptionally large multimodel ensemble of 42 present‐generation climate models to test whether NASPG mean state biases systematically affect the representation of decadal variability. Temperature and salinity biases in the Labrador Sea covary and influence whether density variability is controlled by temperature or salinity variations. Ocean horizontal resolution is a good predictor of the biases and the location of the dominant dynamical feedbacks within the NASPG. However, we find no link to the spectral characteristics of the variability. Our results suggest that the mean state and mechanisms of variability within the NASPG are not independent. This represents an important caveat for decadal predictions using anomaly assimilation methods.