MEDIA RELEASE - HEAD OFFICE

Reduced availability of weather satellite data

The Bureau of Meteorology, which cooperates with the provider of the satellite, the Japan Meteorological Agency (JMA), in its routine operation as part of the World Meteorological Organization's World Weather Watch, has advised that, as from 0100 UTC on 4 July, the imagery from GMS-5 will extend only to around 49°S and the observation frequency will be reduced from 28 to 16 images per day with imagery available at: 0000, 0300, 0500, 0530, 0600, 0900, 1100, 1130, 1200, 1500, 1700, 1730, 1800, 2100, 2300 and 2330 UTC.

The GMS-5 satellite, which has already exceeded its design life of five years, was to have been replaced by a new-generation satellite, MTSAT-1, in November 1999 but a launch vehicle failure led to the loss of MTSAT-1. Its replacement, MTSAT-1R, will not be ready for launch for another two years.

The reduced frequency and latitudinal coverage from GMS-5 has been necessary to extend its operational life and maximise the prospect of its continuing in operation until MTSAT-1R can take over.

The reduction in satellite information can be expected to have some impacts on public forecasting and warning services, although the effect will only be slight, so long as the presently proposed coverage is maintained. Some of the Bureau's data services will also be affected. Any service providing hourly frequency of pictures will now be updated less frequently, and any service currently including "full disk" pictures which show the whole earth hemisphere, will show a black area south of 49°S with no information.

In collaboration with the JMA and other National Meteorological Services and satellite operators, the Bureau of Meteorology has been exploring options for minimising the impact of the reduced imagery from GMS-5. Should the availability of GMS imagery have to be further curtailed, the Bureau will begin issuing a substitute set of satellite images based on a composite of images from the US NOAA polar-orbiting satellites and, as available, other geostationary satellites to the west and east.

The substitute satellite pictures will not be as frequent or as convenient as those from GMS-5, which is a geostationary satellite (effectively stationary above the equator) located in

Australian longitudes, showing the full disk of the earth with Australia very close to the centre of the picture. However, they will be able to be used quite effectively to offset much of the impact of the reduction or loss of GMS-5 imagery on routine forecasting services.

Contacts:
Dr John Zillman, Director, Bureau of Meteorology, tel: (03) 9669 4560

Dr Bill Downey, Deputy Director (Research and Systems), Bureau of Meteorology
tel: (03) 9669 4371, e-mail: w.downey@bom.gov.au

Robert Wright, Acting Deputy Director (Services), Bureau of Meteorology
tel: (03) 9669 4217, e-mail: r.wright@bom.gov.au

Michael Willmott, Acting Supervisor of Operations, National Meteorological and Oceanographic Centre,
tel: (03) 9669 4033, e-mail: m.willmott@bom.gov.au

John Beard, Acting Superintendent, Satellite Section, Bureau of Meteorology
tel: (03) 9669 4594, fax: (03) 9669 4736 / 4168, e-mail: j.beard@bom.gov.au

Further website information:
Reduced availability of GMS-5 images: http://www.bom.gov.au/sat/gms_status.shtml

Current Australian region satellite images: http://www.bom.gov.au/weather/satellite/

Archive of GMS images (loops available): http://www.bom.gov.au/sat/archive_new/gms/

3-D animation of GMS-5 orbit: http://liftoff.msfc.nasa.gov/RealTime/Jtrack/3d/JTrack3D.html
(wait for separate window to appear, then: View/Orbit Path,
Satellite/Select/View/Only Selected, Satellite/Select/Types/Japan, Satellite/Select/ GMS 5,
Options/Update Rate/1/4 second, Options//Timing/x1000 )

Scale models: Scale models and illustrations of the GMS-5 satellite are on display in the Bureau's Melbourne exhibition area, ground floor, 150 Lonsdale Street, open 8am to 5.30pm weekdays.

Full globe image from GMS-5

The first of the GMS series of weather satellites,
similar in appearance to GMS-5