ECMWF Reanalysis

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ECMWF REANALYSISGo to Dataset:

ECMWF has reanalyzed 15 years (1979-1993) of data using a special version of their operational data assimilation system and model. The resulting analyses include full model resolution analyses (Spectral T106/Gaussian N80 [about 1.125°], and 31 vertical hybrid levels or 17 pressure levels, 4x/day), reduced resolution analyses (2.5°, 17 pressure levels, 4x/day), and climate and statistics data. The archival format is GRIB.

ECMWF's page on their reanalyses

Availability of the reanalyses

The following datasets comprise the DSS ECMWF reanalysis archive. The "basic" datasets are the reduced resolution analyses, and the "advanced" are the full resolution analyses.

ds115.0 ECMWF Re-analysis basic global surface data
ds115.1 ECMWF Re-analysis basic global upper air data
ds115.2 ECMWF Re-analysis basic supplementary fields
ds115.3 ECMWF Re-analysis advanced global surface data
ds115.4 ECMWF Re-analysis advanced global upper air data
ds115.5 ECMWF Re-analysis advanced global supplementary fields
ds115.6 ECMWF Re-analysis advanced global upper air moisture data

By agreement with ECMWF, DSS can only distribute ECMWF data to government and academic researchers in the U.S., and to researchers in Canada who are affiliated with UCAR. If you do not meet these requirements but are interested in ECMWF data, please contact them directly at data.services@ecmwf.int .

Which analyses to use?

ECMWF will continue to produce, and DSS will continue to distribute, the ECMWF/TOGA (WCRP) analyses (ds111.0, ds111.1, ds111.2, and ds111.3). Here are some considerations for new users who are undecided about which group of datasets to use:

WCRP analyses (ds111.x) Reanalyses (ds115.x)

basic: .2, .5 advanced: .0, .1, .3 basic: .0, .1, .2 advanced: .3, .4, .5, .6

Period of record 1985-ongoing 1979-1993

Model Changes during period Consistent during period

Horizontal resolution 2.5° T106/N80 2.5° T106/N80

Vertical resolution 15 pressure levels (14 pre 1990) 17 pressure levels 31 model levels

Daily frequency 2x/day 4x/day 4x/day

Parameters available 6 upper air
9 surface 6 upper air
17 or 19 surface
9 supplementary 7 upper air
26 surface
16 supplementary 8+4 upper air
26 surface
16 supplementary

Data volume moderate high high very high

	WCRP analyses (ds111.x)	Reanalyses (ds115.x)
	basic: .2, .5	advanced: .0, .1, .3	basic: .0, .1, .2	advanced: .3, .4, .5, .6
Period of record	1985-ongoing	1979-1993
Model	Changes during period	Consistent during period
Horizontal resolution	2.5°	T106/N80	2.5°	T106/N80
Vertical resolution	15 pressure levels (14 pre 1990)	17 pressure levels	31 model levels
Daily frequency	2x/day	4x/day	4x/day
Parameters available	6 upper air 9 surface	6 upper air 17 or 19 surface 9 supplementary	7 upper air 26 surface 16 supplementary	8+4 upper air 26 surface 16 supplementary
Data volume	moderate	high	high	very high

Alternatively one may use the NCEP/NCAR reanalyses.

You can also view inventories of the data that DSS provided to ECMWF for their reanalysis.

An email mailing list exists to distribute bulletins from NCAR/DSS and ECMWF about ECMWF datasets at NCAR such as announcements of data updates, problems which have been discovered, and changes to software. This mailing list covers the ECMWF/TOGA (WCRP) archive as well as the reanalyses. Previous bulletins are available. If you wish to be added to this mailing list, send email to Joey Comeaux (joey@ucar.edu).

Updated 22 July 2005