Twentieth Century Reanalysis (V2): Opportunities for Improvement
- 7 Nov 2014: Please redownload the 1938 daily 2m air temperature file if you acquired it between 8/14/2014 and 11/7/2014 as it was corrupted. Also, 2m air temperature files before 1940 were in netCDF3 format during that time. Please redownload for netCDF4
.
- 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.
- 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.
- 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.
- 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.
- 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.
- (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.