Southern Hemisphere midlatitude atmospheric variability of the NCEP-NCAR and ECMWF reanalyses

Alessandro Dell'Aquila, Paolo M. Ruti, Sandro Calmanti, Valerio Lucarini

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We compare the representation of the Southern Hemisphere midlatitude winter variability in the NCEP-NCAR and ERA40 reanalyses by using the Hayashi spectral technique. We find important discrepancies in the description of the atmospheric waves at different spatial and temporal scales. ERA40 is generally characterized by a larger variance, especially in the high-frequency spectral region. Compared to the Northern Hemisphere, the assimilated data are relatively scarce particularly over the oceans, and they provide a weak constraint to the assimilation system even in the period when satellite data are available. In the presatellite period the discrepancies between the two reanalyses are large and randomly distributed; after 1979 the discrepancies are systematic. This study suggests that, as for the winter midlatitude variability in the Southern Hemisphere, a well-defined picture to be used in the evaluation of climate model simulations is still lacking because of the nonconsistency of the reanalyses. Copyright 2007 by the American Geophysical Union.
Original languageEnglish
Article numberD08106
Pages (from-to)-
JournalJournal of Geophysical Research
Issue number8
Publication statusPublished - 27 Apr 2007
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

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