title: Earth's energy imbalance since 1960 in observations and CMIP5 models.
abstract: Observational analyses of running 5 year ocean heat content trends (Ht) and net downward top of atmosphere radiation (N) are significantly correlated (r∼ 0.6) from 1960 to 1999, but a spike inHtin the early 2000s is likely spurious since it is inconsistent with estimates ofNfrom both satellite observations and climate model simulations. Variations inNbetween 1960 and 2000 were dominated by volcanic eruptions and are well simulated by the ensemble mean of coupled models from the Fifth Coupled Model Intercomparison Project (CMIP5). We find an observation-based reduction inNof - 0.31 ± 0.21 W m-2between 1999 and 2005 that potentially contributed to the recent warming slowdown, but the relative roles of external forcing and internal variability remain unclear. While present-day anomalies ofNin the CMIP5 ensemble mean and observations agree, this may be due to a cancelation of errors in outgoing longwave and absorbed solar radiation.
  
  
  CONCLUSIONS
  Observed maximum in ocean heat content trend in early 2000s is likely spuriousNet incoming radiation (N) reduced by 0.31 ± 0.21 W m-2during the warming pausePresent-day estimates ofNmay contain opposing errors in radiative components.
authors.affiliation: Met Office Hadley Centre Exeter, UK.
authors.forename: Doug M
authors.initials: DM
authors.lastname: Smith
authors.affiliation: Department of Meteorology, University of Reading Reading, UK.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Allan
authors.affiliation: National Oceanography Centre Southampton, UK.
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Coward
authors.affiliation: Met Office Hadley Centre Exeter, UK.
authors.forename: Rosie
authors.initials: R
authors.lastname: Eade
authors.affiliation: Met Office Hadley Centre Exeter, UK.
authors.forename: Patrick
authors.initials: P
authors.lastname: Hyder
authors.affiliation: Department of Meteorology, University of Reading Reading, UK.
authors.forename: Chunlei
authors.initials: C
authors.lastname: Liu
authors.affiliation: NASA Langley Research Center Hampton, Virginia, USA.
authors.forename: Norman G
authors.initials: NG
authors.lastname: Loeb
authors.affiliation: Met Office Hadley Centre Exeter, UK.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Palmer
authors.affiliation: Met Office Hadley Centre Exeter, UK.
authors.forename: Chris D
authors.initials: CD
authors.lastname: Roberts
authors.affiliation: Met Office Hadley Centre Exeter, UK.
authors.forename: Adam A
authors.initials: AA
authors.lastname: Scaife
keywords: net radiation; ocean uptake