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Reanalysis of global atmospheric data for the period 1979-1993


To develop a global atmospheric data assimilation system to
analyze in an internally consistent way the record of atmospheric
data (from the earth's surface to 10 hPa) for the period
1979-1993; subsequently to produce a validated and documented
15-year data-set of assimilated data at high horizontal and
vertical resolution. This data-set will provide global three
dimensional descriptions of the velocity, temperature,
geopotential and humidity fields for the atmosphere; analyses or
diagnoses of surface parameters (temperature, pressure, soil
moisture, etc.), surface fluxes of heat, moisture, radiation and
other quantities will be included.

The ECMWF Re-Analysis (ERA) data-sets will be derived from a
special version of the ECMWF operational data assimilation

Analyses of atmospheric variables will be produced
either by optimal interpolation of irregularly-spaced
observational data, or by a three dimensional variational system,
to produce increments to be added to global short-range
forecasts. The short-range forecasts will use a global spectral
model with a triangular truncation at wavenumber 106 - the
horizontal resolution of these global analyses will be
approximately 100 km.

The ERA production system,
once established, will remain consistent, resulting in data
unaffected by the periodic changes introduced over the years
within a daily operational system. The real-time ECMWF data
collection (which has a 3-day cut-off) will be augmented by First
Global Geophysical Experiment (FGGE) and Alpine Experiment
(ALPEX) level II-B data, NOAA Climate Analysis Centre and UK
Meteorological Office delayed mode sea surface temperature (SST)
analyses (which will serve as the oceanic lower boundary
condition for the atmospheric data assimilation), the COADS ship
data-set, additional radio-sonde data-sets available from
National Meteorological Centres, and NOAA satellite radiance data
for the 15-year period.

Data-sets will be produced in three main
phases - phase A1 (pilot analyses for June 1985) - phase
A2 (analyses for 1979 - the FGGE year for which there exists a
number of comparable data-sets) - phase A3 (analyses for
1980-1993). The pilot analyses and the FGGE year analyses will
be used by the production team at ECMWF, and validation teams
elsewhere to assess critically the quality of the analyses
before embarking on the remaining period. A comprehensive set of
data services will ensure the accessibility of the resulting data
sets to the scientific community. Services will be based on full
resolution data, supplemented by data at reduced resolution and
statistical data.

Funding Scheme

CSC - Cost-sharing contracts


European Centre for Medium-range Weather Forecasts - ECMWF
Shinfield Park
RG2 9AX Reading
United Kingdom

Participants (1)

Bundesstra¯e 55
20146 Hamburg