Twentieth Century Reanalysis (V2): Opportunities for Improvement

  1. 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 estim ates.
  2. 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.
  3. 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.
  4. (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.