Background

Since 2005, ECMWF has generated model-simulated satellite images out to five days from the 00 UTC and 12 UTC  cycles of the operational HRES forecast for all operational geostationary satellites (i.e., Meteosat-7, Meteosat-10, MTSAT-2, GOES-13 and GOES-15). The simulated images are archived in MARS as GRIB edition 1 files and have been presented on the ECMWF website as PostScript image files. The forecast-generated satellite images have been based on the resolution of the HRES global model with 3-hourly output from T+0 to T+48 and 6-hourly output to T+120.

Up to and including IFS cycle 41r1, the satellite images in both the window and water vapour (WV) channels were simulated over each of the 5 geostationary satellite’s disk. Brightness temperatures were calculated using the same radiative transfer algorithm (e.g., RTTOV-11) as in the operational data assimilation and using the relevant atmospheric model profiles (temperature, specific humidity, ozone mass mixing ratio, cloud cover, specific cloud liquid water content, specific cloud ice water content, specific rain water content, specific snow water content) and the relevant surface parameters (skin temperature, 10m u and v wind components, 2m temperature and 2m dewpoint temperature, volumetric soil water layer 1, convective available potential energy).

Errors in simulated satellite images can derive from errors in the NWP parameters, on which the simulation is based, the resolution of the model and RTTOV model performance.

Updates to the simulated satellite images at IFS cycle 41r2

The simulated satellite images at IFS cycle 41r2 have been enhanced in various aspects.

For the time being only Meteosat-10-like simulated satellite data will be made available. The central wavelength of the channels on other platforms is quite close to those selected to be produced, archived and disseminated.

Example images

48-hour global simulated Meteosat-10 SEVIRI imagery at 10.8 μm (channel 9) from the ECMWF model cycle 41r2 at TCO1279 / O1280 horizontal resolution with 137 vertical levels run on 1 March 2016 at 00 UTC.

48-hour global simulated Meteosat-10 SEVIRI imagery at  6.30 μm (channel 5)from the ECMWF model cycle 41r2 at TCO1279 / O1280 horizontal resolution with 137 vertical levels run on 1 March 2016 at 00 UTC.
Animation of 10 day global simulated Meteosat-10 SEVIRI imagery at 10.8 μm (channel 9) from the ECMWF model cycle 41r2 at TCO1279 / O1280 horizontal resolution with 137 vertical levels run on 1 March 2016 at 00 UTC.Animation of 10 day global simulated Meteosat-10 SEVIRI imagery at  6.30 μm (channel 5)from the ECMWF model cycle 41r2 at TCO1279 / O1280 horizontal resolution with 137 vertical levels run on 1 March 2016 at 00 UTC.

Technical information

The simulated satellite data are specified using the satellite identifer, instrument, channel number and central wavelength as given in the WMO Manual on codes:

.  For the simulated satellite data based on Meteosat-10 these are as in the table below:

SatelliteInstrumentSatellite IDInstrument TypeChannelCentral wavelength (μm)Description
Meteosat-10

SEVIRI (Spinning Enhanced Visible and InfraRed Imager)

5720756.30Water Vapour at ~300 hPa
67.36Water Vapour at ~500 hPa
910.79Infra-red

GRIB encoding

The simulated satellite data fields are encoded in GRIB edition 2 with the parameter set to Cloudy brightness temperature:

paramIdshortNamenameunitsGRIB edition
260510clbtCloudy brightness temperatureKelvin2

The product description uses productDefinitionTemplateNumber=32 (analysis or forecast at a horizontal level or in a horizontal layer at a point in time for simulated (synthetic) satellite data.  The relevant GRIB API keys are encoded as:

GRIB  key name
satelliteSeriessatelliteNumber
ident
instrumentType
instrument
channelNumber
channel
NB
numberOfContributingSpectralBands
scaleFactorOfCentralWaveNumberscaledValueOfCentralWaveNumber (units: m-1)
33357207510158800
610135800
91092700

Other GRIB API keys describing the product are:

KeyValueDescription
discipline  3Space products
parameterCategory1Quantitative products

parameterNumber

14

 Cloudy brightness temperature

GRIB API version at least 1.14.5 needs to be used in order to decode the simulated satellite data products.

Availability of the simulated satellite images in MARS

The simulated satellite data are archived in MARS under TYPE=SSD (Simulated Satellite Date).  They can be viewed in the MARS Catalogue at:

A sample MARS request for retrieving the fields at all post-processing time steps of a single forecast is:

RETRIEVE,
    STREAM     = OPER,
    CLASS      = OD,
    EXPVER     = 0001,
    DATE       = -1,
    TIME       = 12,
    TYPE       = SSD,
    IDENT      = 57,
    INSTRUMENT = 207,
    PARAM      = 260510,
    CHANNEL    = 9,
    STEP       = 0/3/6/9/12/15/18/21/24/27/30/33/36/39/42/45/48/54/60/66/72/78/84/90/96/102/108/114/120/132/144/156/168/180/192/204/216/228/240,
    TARGET     = "meteosat-10.channel9.grib2"

The fields are stored on the model O1280 octahedral reduced Gaussian grid.  Any MARS post-processing keywords, such as AREA or GRID can be applied to the request to interpolate the fields to lower resolutions or geographical sub-areas.

Availability of the simulated satellite images in dissemination

 

History of simulated satellite images at ECMWF

Prior to the implementation of IFS cycle 41r2, the simulated satellite images were stored in MARS with TYPE=SIM and REPRES=SV (Space View) for the IDENT, INSTRUMENT and CHANNEL as specified in the table below.

NameOperatorSectorLongitudeSinceSatellite IDInstrumentinstrument typeChannelCentral
wavelength
(μm)
Dimensions
(pixels)
Satellite
subpoint
(pixels)
Meteosat-7EUMETSATIndian Ocean54.5° E2009-03-1054MVIRI20526.342500x25001250x1250
311.52
GOES-13NOAAWest Atlantic75.0° W2010-04-09257Imager61536.541250x1250625x625
410.67
MTSAT-2JMAWest Pacific145.0° E2011-01-25172JAMI294210.81250x1250625x625
46.8
GOES-15NOAAEast Pacific135.0° W2012-04-25259Imager61536.551250x1250625x625
410.68
Meteosat-10EUMETSATEast Atlantic2013-01-1457SEVIRI20756.301856x1856928x928
67.36
910.79

These products have been encoded using GRIB edition 1.

An example MARS request for retrieving the old-style (pre-IFS cy41r2) simulated satellite images at all post-processing time steps to day 5 and for a forecast date "YYYYMMDD" prior to 20160308 is:

RETRIEVE,
    CLASS = OD, 
    TYPE = SIM,
    STREAM = OPER,
    EXPVER = 0001,
    REPRES = SV,
    DATE = YYYYMMDD,
    TIME = 0000,
    STEP = 0/3/6/9/12/15/18/21/24/27/30/33/36/39/42/45/48/54/60/66/72/78/84/90/96/102/108/114/120,
    DOMAIN = G,
    CHANNEL = 9,
    IDENT = 57,
    INSTRUMENT = 207,
    TARGET = ”old_simulated_meteosat-10.channel9.grib”