Climatic Research Unit: Data

NCEP/NCAR Reanalysis

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2020 Data Added (Ian Harris, 15 April 2021)


2019 Data Added (Ian Harris, 8 July 2020)

Problems detected (& corrected) with 2017 & 2018 files (Ian Harris, 22 October 2019)

2018 Data Added (Ian Harris, 17 July 2019)

2017 Data Added (Ian Harris, 9 November 2018)

2015, 2016 Data Added (Ian Harris, 20 February 2017)

2014 Data Added (Ian Harris, 21 Jul 2015)

2013 Data Added (Ian Harris, 21 Jan 2014)

2011 & 2012 Data Added (Ian Harris, 30 May 2013)

2010 Data Added (Ian Harris, 18 May 2011)

2008 & 2009 Data Added (Ian Harris, 6 Oct 2010)

1948-1957 Data Added (Ian Harris, 22 Jul 2008)

2007 Data Added (Ian Harris, 17 Apr 2008)

2006 Data Added (Ian Harris, 11 Mar 2007)

2005 Data Added (Ian Harris, 13 Jan 2006)

2004 Data Added (Ian Harris, 28 Nov 2005)

2003 Data Added (Ian Harris, 11 May 2004)

SURFACE TEMPERATURE ADDED (Ian Harris, 10 December 2003)


ALL DATASETS UPDATED TO 2002 (Ian Harris, 23 June 2003)

LAND/SEA MASKS ADDED (Ian Harris, 16 December 2002)

Land/Sea Masks for regular and Gaussian grids have been added.

NEW WINDOW ONLINE (Ian Harris, 9 July 2002)

The new Quarter-Spherical Window (0N-90N; 90W-90E) is now in use (see table below).

The old window data (here) has now been entirely replaced.

Please address any requests for new variables to me.

BAD DATA REPLACED (Ian Harris, 23 May 2002)

The TOVS Problem has been resolved and only corrected data appears on this site.

Anyone wishing to access the old (potentially incorrect) data in order to evaluate the extent of the problem should contact me.

The reanalysis data are available for numerous meteorological parameters, as 6-hourly observations, and daily and monthly averages.  They generally extend back from the present day to 1948, and cover the entire globe.  For a full description of the project which sourced this data, you should visit the  NCEP/NCAR Reanalysis 1 Home Page.

The source data were provided by the Physical Sciences Laboratory, who provide a full description of the data. Please credit them if you use this data! Follow the 'description' link for details.

The work done at CRU has extracted spatial subsets of the data, and reformatted from netCDF to plain ASCII.  All enquiries about the validity of the data, or its development, should be addressed to the PSL or to the contact at the foot of the dataset page above..

Generic Information about the NCEP/NCAR Reanalysis data files on this site

Only daily and 6-hourly data sets are referenced here, for a Quarter-Spherical window covering Eastern America and West/central Eurasia. Monthly data sets, and some alternative windows have been extracted, although they will be superceded by the new window. Email for details (see contact information at foot of page).


Air Temperature at Surface NEW Surface daily 6-hourly
Air Temperature at 2m (problem report) Surface Flux daily 6-hourly
Maximum Air Temperature at 2m (problem report) Surface Flux daily 6-hourly
Minimum Air Temperature at 2m (problem report) Surface Flux daily 6-hourly
Air Temperature Pressure Levels daily 6-hourly
Geopotential Height Pressure Levels daily 6-hourly
Precipitation Rate Surface Flux daily 6-hourly
Precipitable Water Surface (see note) daily 6-hourly
Relative Humidity Pressure Levels daily 6-hourly
Specific Humidity at 2m Surface Flux daily 6-hourly
Specific Humidity Pressure Levels daily 6-hourly
Sea Level Pressure (problem report) Surface daily 6-hourly
U-Wind Component Pressure Levels daily 6-hourly
U-Wind Component Surface daily 6-hourly
U-Wind Component at 10m Surface Flux daily 6-hourly
V-Wind Component Pressure Levels daily 6-hourly
V-Wind Component Surface daily 6-hourly
V-Wind Component at 10m Surface Flux daily 6-hourly
Land/Sea Mask for Surface and Pressure Level Data n/a lsmask lsmask
Land/Sea Mask for Surface Flux Data n/a lsmask lsmask

Note: Precipitable Water, although classed as a Surface parameter, applies to the entire atmospheric column (hence, 'eatm' in the filenames).

Last updated: April 2021, Ian Harris
Please refer all enquiries, errors, omissions and ambiguities to me:

These datasets are made available under the Open Database License.
Any rights in individual contents of the datasets are licensed under the
Database Contents License under the conditions of Attribution and Share-Alike.
Please use the attribution Climatic Research Unit, University of East Anglia