Geostationary Data and Applications

Overview | Introduction | Geostationary Data and Applications | NOAA Data and Applications
Other Satellites | References

Geostationary data from the GOES-9 satellite is the mainstay of the analysis and prognosis system of the Bureau. GOES-9 is operated by joint effort of JMA and the United States' NOAA NESDIS over the Western Pacific (More information on the backup of GMS-5 with GOES-9). The imagery is used directly for synoptic analysis and is available approximately five minutes after the ingest of the final scan line. The GOES-9 data is used extensively within the Bureau to assist in real time analysis and forecasting (for example, displaying the imagery directly in hourly loops) and the radiances are fed into the Bureau's global and mesoscale Numerical Weather Prediction (NWP) models. The data is made available as a Man-computer Interactive Data Access System (McIDAS) area file to both the National Meteorological Operations Centre (NMOC) and the Regional Offices via the Local Area Network (LAN).

Geostationary satellites such as GOES-9 orbit around the earth over the equator at a height of approximately 35,800 km. They complete one orbit every 24 hours so that their period is sychronised with that of the earth's rotation about its own axis. They therefore remain over the same location on the equator. They are stabilised by spinning rapidly (spin stabilised). With this system images are built up by scanning with a mirror that is tilted in small sucessive steps from the north pole to south pole at a rate such that on each rotation of the satellite an adjacent strip of the earth is scanned. It takes 25 minutes to scan the full earth's disk. This builds a picture 10,000 pixels square for the visible images (1.25 km resolution) and 2,500 pixels square (5 km resolution) for the infrared and water vapour images.

The current (real time) GOES-9 data and previous GMS data are archived in McIdas format. McIdas stores the data as individual area files (Visible - approximately 450 Mbytes; Infrared Channel 4, Infrared Channel 5, Near Infrared Channel 2 and Infrared Channel 3 (Water Vapour) - approximately 30 Mbytes each) at full resolution. The GMS5 data was also archived in ASDA format as a 110 Mbyte file in a format as close to the original format as practicable .

The Bureau archives data from GOES-9, GMS 5 (JMA) and Feng Yun 2 (China Meteorological Service) for research, climate and case studies of severe weather events. A browse service is available to help with ordering data from the archive.

The main advantage of the geostationary over polar satellites is the high temporal resolution of their data. The disadvantage is the their limited spatial resolution, which is a consequence of their distance from earth. Also distortion at high latitudes limits useful information to the belt between 70° N and 70° S

Applications

Solar Radiation

Daily surface solar exposure is estimated using a physical model of radiative transfer within the atmosphere, visible spectrum satellite data and other ancillary data (Weymouth 1994 and Le Marshall 2001). This model is a two band developed for data from GMS-5. The model is running operationally within the Bureau and output is available on the Internet under a registered user service. Validation data from the model has been archived since July 1997 and full grid data has been stored from August 1998.

[More Information: Solar Radiation Model Description | Solar Radiation Subscription Service ]

Cloud and Water Vapour Motion Vector Winds

The Bureau currently generates, on an hourly basis, high spatial and temporal resolution cloud and water vapour motion vectors using geostationary satellite data. The data is assimilated into the Bureau's Numerical Weather Prediction (NWP) models operationally in real time. Impact has also been made using these winds in local NWP models for tropical cyclone forecasting.

[Current Australian Region Cloud Drift Winds | Other Regions]

Volcanic Ash Detection

In the Bureau work is continuing on the use of GMS-5 (and AVHRR) satellite data for the discrimination of volcanic ash clouds from water/ice clouds and reducing the incidence of false alarms (Potts and Tokuno, 1996). The Bureau's Volcanic Ash Advisory Centre (VAAC) in Darwin provides advice on volcanic ash clouds within its area of responsibility for the aviation industry. The advisory messages are based on advice from aircraft, volcanological authorities, GOES-9 and NOAA satellite imagery and a volcanic ash trajectory forecast model.

[Darwin Regional Office: Volcanic Ash Service | NOAA Volcanic Ash Site]

The Bureau has implemented an Atmospheric Transport Model (ATM) and maintains the necessary meteorological data files to respond promptly with trajectory and dispersion guidance in the event of an incident. The model is based on the Hyspit model developed by NOAA Air Research Laboratory but has been developed further by scientists within the Bureau of Meteorology Research Centre (BMRC).

Data Collection Platforms

The Bureau has a total of 28 Sutron Automatic Weather Station (AWS) DCPs installed around the Australian region, mainly at remote locations on islands, which operate via GMS-5. No further installations are planned for the Sutron equipment. Instead, the Bureau and Almos Systems P/L have given priority to the development of a new AWS that will operate as a GMS DCP. This will enable the new AWS to maintain and increase the number of AWSs within the existing network.

The Bureau also deploys a number of drifting buoys in ocean areas around Australia, especially in the Southern Ocean. These report via the Argos DCPLS on board NOAA Satellites

GMS Pathfinder Project