Geostationary satellites
Geostationary satellites, such as
Himawari, orbit the
Earth over the equator at a height of approximately 35 800 km. They
complete one orbit every 24 hours, in sync with the Earth's rotation
about its own axis. This ensures that geostationary satellites remain
over the same location above the equator, allowing frequent imaging of a given region of Earth's surface and atmosphere. A number
of geostationary satellites are positioned around the globe for
continuous coverage.
Imaging capabilities of geostationary satellites vary based on model and age. Baseline capabilities include imaging in the visible and infrared parts of the spectrum, commonly at a resolution of 1 km and 4 km (respectively), but Japan’s Advanced Himawari Imager records visible images at 0.5–2 km resolution. Due to the nature of its orbit, a geostationary satellite is capable of scanning the Earth to 70° of latitude or longitude in each direction from the sub-satellite point (the point on the equator directly below the satellite).
More information on the Himawari satellite is available on JMA’s website.
Polar orbiting satellites
Polar orbiting satellites pass over the Earth’s poles at a height of approximately 700–850 km. Each satellite follows a nearly fixed orbit while the Earth rotates beneath. Additionally, polar orbiting satellites tend to be placed in a sun-synchronous orbit, which means that the satellite flies over any given location on Earth at a set local time.
The areas scanned by each pass (swath) are nearly adjacent at the equator on consecutive passes. Further pole-wards the passes progressively overlap. Imaging sensors carried on-board these satellites generally have a swath width of about 2600 km, and by completing 14 orbits per day one satellite can provide an almost complete coverage of the globe twice a day. The instrument on the satellite points continuously at the Earth, and images are built up by a mirror on the satellite scanning from side to side at right angles to the orbital path.
One of the main benefits of polar orbiting satellites is that they tend to have a wider variety of equipment on board. Their other benefit is that they deliver frequent coverage of polar regions—areas not visible from geostationary satellites.
Data reception
With access to meteorological satellite data from Japan, the US, Europe, South Korea and India, Australia is well served by regular imagery to support operations and research of national weather services like the Bureau of Meteorology. The Bureau is grateful to our international partners for the global exchange of meteorological data. In particular, Himawari represents a significant contribution by Japan to the space-based observations part of the World Meteorological Organization's Global Observing System.
Satellite ground station network
The Bureau operates a national scale network of satellite ground station antennas at:
- Melbourne, Victoria
- Darwin, Northern Territory
- Learmonth, Western Australia
- Casey and Davis stations in Antarctica
The receiving stations provide:
- Low latency observations for forecast models
- National-scale information for many of our products for the Australian community
We are also part of the Australian National Ground Segment Technical Team. This is a partnership with: