Premium
Internal climate memory in observations and models
Author(s) -
Monselesan Didier P.,
O'Kane Terence J.,
Risbey James S.,
Church John
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 - 10.1002/2014gl062765
Subject(s) - climatology , coupled model intercomparison project , environmental science , latitude , middle latitudes , climate model , variance (accounting) , oscillation (cell signaling) , ensemble average , spatial ecology , atmospheric sciences , climate change , geology , oceanography , ecology , accounting , geodesy , biology , business , genetics
Attribution of cause of climate change is hindered by our ability to separate internal low‐frequency variability from the forced response in the climate system. We characterize the spatiotemporal characteristics of internal variability by comparing ensemble averages of in‐band fractional variances in Coupled Model Intercomparison Project Phase 5 (CMIP5) preindustrial control simulations to estimates from observations and reanalyses. For sea surface temperature and sea level height anomalies both models and observations show that variability on time scales less than 5 years is predominantly in the tropics and has the spatial signature of El Ni ñ o–Southern Oscillation. On progressively longer time scales the variance moves to the extratropics and from middle to higher latitudes while displaying spatially coherent features. The CMIP5 models show good agreement in the spatial and temporal apportioning of in‐band variance when the variances are normalized.