Estimating low‐frequency variability and trends in atmospheric temperature using ERA‐Interim

作者：Adrian John Simmons, Paul Poli, Dick P. Dee, Paul Berrisford, Hans Hersbach, S Kobayashi, Carole Peubey · 发表于：Quarterly Journal of the Royal Meteorological Society · 年份：2013 · DOI：10.1002/qj.2317 · 被引用次数：188 · 研究领域：Climate variability and models、Meteorological Phenomena and Simulations、Oceanographic and Atmospheric Processes

Abstract Low‐frequency variability and trends in temperature from 1979 to 2012 are examined. Observational improvements are noted and near‐surface behaviour of the ECMWF ERA‐Interim reanalysis is reviewed. Attention is then focussed on how closely ERA‐Interim fits the upper‐air data it assimilates, the bias adjustments it infers for satellite data, and its agreement with the ERA‐40, MERRA and JRA‐55 reanalyses and with model simulations. Global‐mean fits to independently homogenised radiosonde temperatures and variationally adjusted satellite brightness temperatures are mainly within 0.1 K in the troposphere, with some degradation over time from assimilating varying amounts of aircraft and rain‐affected microwave‐radiance data, and from a change in source of sea‐surface‐temperature analysis. Lower‐tropospheric warming appears to be somewhat underestimated. Temperature variations in the tropical upper troposphere correlate well with those at the surface, but amplitude is more than doubled, in agreement with modelling. Specific humidity varies in concert; relative humidity is largely uniform, but dips during El Niño events. Agreement with the other reanalyses is particularly close in the lower stratosphere, where radiance data and the background model constrain cooling to be slightly slower than in the homogenised radiosonde data. Perturbations to global‐mean temperatures from underestimating warming following the El Chichón and Pinatubo volcanic eruptions and from assimilating...