Twentieth Century Reanalysis (V2): Opportunities for Improvement

  1. 4 Sep 2014: There were missing dates for the files below (unknown cause). Please re-download these files if you acquired them before Sep 4 2014:
    ulwrf.ntat.1873.nc & uswrf.ntat.1873.nc in gaussian/monolevel ensemble means
    15Z21May to 21Z31May were missing
    ulwrf.ntat.1875.nc & uswrf.ntat.1875.nc in gaussian/monolevel ensemble means. The daily averages and monthly means were impacted for 1875 and should be redownloaded as well
    15Z21May to 21Z31May were missing
    ulwrf.ntat.1875.nc & uswrf.ntat.1875.nc in gaussian/monolevel ensemble spreads
    May was missing in sub daily and daily.
    ulwrf.ntat.mon.mean.nc & uswrf.ntat.mon.mean.nc in gaussian/monolevel monthly mean ensemble spreads
    May-Dec 1875 were missing.
  2. 14 May 2014: Values after Aug 30 2012 have been recalculated to include additional observations that were missed. Files at all temporal frequencies that include 2012 data have been replaced with updated versions.
  3. 22 March 2013: An additional issue with the specification of Arctic sea ice near the dateline for the period of August 2007 to December 2010 results in lower tropospheric air temperatures with an additional warm bias compared to other reanalysis estimates.
  4. 22 March 2013: An issue with the specification of sea surface temperatures north of 70N in the north Pacific and Arctic near the dateline for the period 1990 and following also contributes to the warm bias in this region.
  5. 7 July 2011: For the days of 6 June 1886, 1 January 1952, 7 July 2004, and 24 January 2007, ensemble mean and spread values derived from every-member 20CRv2 data at the NERSC Science Gateway http://portal.nersc.gov/project/20C_Reanalysis/ will differ from those obtained from here at NOAA ESRL http://www.esrl.noaa.gov/psd/data/gridded/data.20thC_ReanV2.html and NCAR ds131.1 http://dss.ucar.edu/datasets/ds131.1/. The every-member data at the NERSC portal are prior to re-runs to correct problems with the data archiving for these periods. The data online here and at NCAR are derived from the re-run fields.
  6. (originally posted 1/20/2010; updated 7/8/2010) Sea Ice concentration used by the data assimilation system is lower than the specified HadISST1.1 in many coastal regions of the Arctic and Antarctic. This appears to have resulted in a warm bias in the lowest parts of the troposphere of both poles near the land areas, particularly during the non-summer seasons.