TY - JOUR
T1 - Spatial and temporal agreement in climate model simulations of the Interdecadal Pacific Oscillation
AU - Henley, Benjamin J
AU - Meehl, Gerald A
AU - Power, Scott Brendan
AU - Folland, Chris K
AU - King, Andrew D
AU - Brown, Jaclyn Nicole
AU - Karoly, David John
AU - Delage, Francois
AU - Gallant, Ailie
AU - Freund, Mandy
AU - Neukom, Raphael
PY - 2017/3/30
Y1 - 2017/3/30
N2 - Accelerated warming and hiatus periods in the long-term rise of Global Mean Surface Temperature (GMST) have, in recent decades, been associated with the Interdecadal Pacific Oscillation (IPO, Kosaka & Xie 2013; England et al. 2014). Critically, decadal climate prediction relies on the skill of state-of-the-art climate models to reliably represent these low frequency climate variations. We undertake a systematic evaluation of the simulation of the IPO in the suite of 39 Coupled Model Intercomparison Project 5 (CMIP5) models. We track the IPO in pre-industrial (control) and all-forcings (historical) experiments using the IPO tripole index (TPI). The TPI is explicitly aligned with the observed spatial pattern of the IPO, and circumvents assumptions about the nature of global warming. We find that many models underestimate the ratio of decadal-to-total variance in sea surface temperatures (SSTs). However, the basin-wide spatial pattern of positive and negative phases of the IPO are simulated reasonably well, with spatial pattern correlation coefficients between observations and models spanning the range 0.4-0.8. Deficiencies are mainly in the extratropical Pacific. Models that better capture the spatial pattern of the IPO also tend to more realistically simulate the ratio of decadal to total variance. Of the 13% of model centuries that have a fractional bias in the decadal-to-total TPI variance of 0.2 or less, 84% also have a spatial pattern correlation coefficient with the observed pattern exceeding 0.5. This result is highly consistent across both IPO positive and negative phases. This is evidence that the IPO is related to one or more inherent dynamical mechanisms of the climate system.
AB - Accelerated warming and hiatus periods in the long-term rise of Global Mean Surface Temperature (GMST) have, in recent decades, been associated with the Interdecadal Pacific Oscillation (IPO, Kosaka & Xie 2013; England et al. 2014). Critically, decadal climate prediction relies on the skill of state-of-the-art climate models to reliably represent these low frequency climate variations. We undertake a systematic evaluation of the simulation of the IPO in the suite of 39 Coupled Model Intercomparison Project 5 (CMIP5) models. We track the IPO in pre-industrial (control) and all-forcings (historical) experiments using the IPO tripole index (TPI). The TPI is explicitly aligned with the observed spatial pattern of the IPO, and circumvents assumptions about the nature of global warming. We find that many models underestimate the ratio of decadal-to-total variance in sea surface temperatures (SSTs). However, the basin-wide spatial pattern of positive and negative phases of the IPO are simulated reasonably well, with spatial pattern correlation coefficients between observations and models spanning the range 0.4-0.8. Deficiencies are mainly in the extratropical Pacific. Models that better capture the spatial pattern of the IPO also tend to more realistically simulate the ratio of decadal to total variance. Of the 13% of model centuries that have a fractional bias in the decadal-to-total TPI variance of 0.2 or less, 84% also have a spatial pattern correlation coefficient with the observed pattern exceeding 0.5. This result is highly consistent across both IPO positive and negative phases. This is evidence that the IPO is related to one or more inherent dynamical mechanisms of the climate system.
KW - CMIP5
KW - Interdecadal Pacific Oscillation
KW - IPO
KW - model evaluation
KW - Pacific Decadal Oscillation
KW - Pacific Decadal Variability
KW - PDO
UR - http://www.scopus.com/inward/record.url?scp=85018463850&partnerID=8YFLogxK
U2 - 10.1088/1748-9326/aa5cc8
DO - 10.1088/1748-9326/aa5cc8
M3 - Article
AN - SCOPUS:85018463850
VL - 12
JO - Environmental Research Letters
JF - Environmental Research Letters
SN - 1748-9326
IS - 4
M1 - 044011
ER -