The ERA-15 production system generated re-analyses from December 1978
to February 1994. The following observations were used:
FGGE Level II-B data for 1978/79;
COADS ship and buoy observations;
ALPEX Level II-B data;
ECMWF archive of observations received via the WMO GTS;
additional TEMP and AIREP data from the Japan Meteorological Agency
Australian PAOB surface pressure pseudo-observations from Bureau of
Meteorology (BoM), Melbourne;
TOGA COARE data;
TOVS Cloud Cleared Radiance data;
Hadley Centre GISST and NCEP SST analyses.
The data assimilation system used for ERA-15 had the following characteristics:
Spectral T106 resolution with 31 vertical hybrid levels.
Intermittent statistical (optimum interpolation) analysis with 6
hour cycling and noFGAT.
One dimensional variational (1D-VAR) physical retrieval of TOVS cloud
cleared radiances below 100hPa, and NESDIS operational retrievals above.
No TOVS data were used above 100hPa between 20°N and 20°S.
Diabatic, non-linear normal mode initialisation, five vertical modes.
The Integrated Forecast System (IFS) version of the ECMWF forecast
model with 3-dimensional semi-Lagrangian advection.
Mean orography with a compatible parametrization of the effects of
sub-grid scale orography.
Prognostic soil temperature and soil moisture, with nudging of the
moisture from boundary layer atmospheric humidity analyses.
Prognostic equations for cloud water and ice content and the cloud
ECMWF operational radiation parametrization with prescribed concentrations
of aerosols, CO2 and O3, with O3 varying geographically and seasonally,
the aerosols varying geographically and vertically and the CO2 held
The externally prescribed forcing of the re-analyses, in addition to
the observations, came from the ocean surface temperature (SST) analyses
and the ocean ice cover, determined from SMMR and SSM/I data.
ERA-15 data are available to ECMWF Member States through the MARS archive,
to University users within the U.K. through BADC,
to University users in Germany through
MPI, and to the UCAR community through
NCAR. NCAR also have a web page describing their holdings of ECMWF
re-analysis data. Further information concerning access to data can
be obtained from ECMWF's Data Services.