Satellites

How we use satellite data

We use data from more than 20 geostationary and polar-orbiting satellites.

The data is used for research and in applications such as our:

• weather map
• Antarctic sea ice imaging
• sea surface temperature information.

Our weather map uses:

• data from Japan's Himawari 9 satellite
• satellite images from ArcGIS to provide map settings options.

Geostationary satellites

Geostationary satellites orbit the Earth over the equator at a height of about 35,800 km.

These satellites:

• complete one orbit every 24 hours, in line with the Earth's rotation about its own axis
• remain over the same location above the equator.

This allows them to take frequent images of a given region of Earth's surface and atmosphere.

A geostationary satellite can scan the Earth to 70° of latitude or longitude in each direction. This is measured from a point on the equator directly below the satellite. It's called the sub‑satellite point.

Several geostationary satellites are positioned around the globe for continuous coverage.

Their capability to take images depends on model and age. All geostationary satellites can take images in visible and infrared parts of the spectrum. They usually do this at 1 km and 4 km resolution.

Japan’s Advanced Himawari Imager on the Himawari 9 satellites records visible images at 0.5–2 km resolution.

Himawari 9

Himawari 9 provides most of our geostationary satellite data. This satellite, and its backup sister Himawari 8, are operated by the Japan Meteorological Agency.

They are successors to Japan's multi-functional transport satellites. The instruments on Himawari satellites significantly improved the frequency, resolution and precision of images when launched. This was in 2014 for Himawari 8 and 2016 for Himawari 9.

Himawari satellite benefits

Technological advances in these satellites enhance our ability to detect and monitor:

• the centres of tropical cyclones over the ocean
• thunderstorms, as they develop
• volcanic ash, fire and smoke
• fog and low cloud.

Himawari 9 and its backup 8 orbit in close formation, both at around 140.7° E. This is in line with Japan, Papua and central Australia.

It means the same view is available when operations switch between the satellites. Himawari 9 became the primary satellite in December 2022.

Processing and sharing Himawari data

We have a regional role in sharing observational data from Himawari 9.

The data comes to us free of charge from the JMA through 2 parallel routes:

• HimawariConnect – a dedicated fibre-optic line from Japan to the Bureau
• HimawariCloud – an internet service open to various national meteorological services.

Once received, we process the data into several products. These are sent to our Regional Forecasting Centres and other stakeholders.

Scans of our region are taken every 10 minutes. Data from these scans travels quickly to our forecasters – that is, it has a short latency. This means our forecasts are informed by near real-time information.

The data also feeds into numerical weather prediction models run on our supercomputer.

Meteosat and GOES data

International cooperation gives the Bureau access to other geostationary satellite data.

The location of some satellites means we can't receive data locally, so it is supplied to us. This includes data from:

• European Meteosat
• US Geostationary Operational Environmental Satellites (GOES).

We also get real-time, low resolution Meteosat imagery for our use only. This comes from the European Organisation for Exploitation of Satellites (EUMETSAT).

GOES-East and GOES-West imagery is accessed by agreement with the Space Science and Engineering Centre. The data is received every 3 hours.

Polar orbiting satellites

Polar orbiting satellites pass over the Earth’s poles at a height of about 700–850 km.

These satellites:

• are more affordable for payload due to their low Earth orbit, so carry wider variety of equipment
• deliver frequent coverage of polar regions, which are not visible from geostationary satellites.

Each satellite follows a nearly fixed orbit while the Earth rotates beneath. They are usually in a sun-synchronous orbit. This means that the satellite flies over any given location on Earth at a set local time.

Each pass is called a swath. The areas scanned in each pass are nearly next to the equator on consecutive passes. Further towards the poles, the passes progressively overlap.

Imaging sensors carried on these satellites generally have a swath width of about 2,600 km. Completing 14 orbits in a day, one satellite can provide almost complete coverage of the globe, twice a day.

The imaging instrument points continuously at the Earth. A mirror on the satellite scans side-to-side at right angles to the orbital path. This builds the satellite images.

Aqua and Terra

Aqua and Terra are polar orbiting Earth observation satellites operated by the United States of America's NASA. They are part of a multi-agency program called the Earth Observing System.

Terra is the flagship of the program. This satellite covers the local morning. Aqua images are available early afternoon local time.

Both satellites carry the moderate-resolution imaging spectroradiometer. It can capture 36 spectral bands at varying spatial resolutions – 250 m, 500 m and 1000 m.

Aqua has an atmospheric infrared sounder. This measures the infrared signal sent by the Earth's atmosphere and surface in 2,378 channels. This signal can be used to estimate temperature and water vapour content throughout the atmosphere.

Aqua was launched in 2002, and Terra in 1999. They have far exceeded their design lifetime.

Polar Orbiting Environmental Satellite (POES) Series

The United States' National Oceanic and Atmospheric Administration (NOAA) has operated its POES series for a long time.

The satellites in the series have an advanced very high resolution radiometer. This instrument measures Earth's reflectance in 5 spectral bands. That is, it measures how well the Earth reflects radiant energy.

The satellites send continuous high resolution picture transmission data. We receive data from 2 POES series satellites:

• NOAA‑18
• NOAA‑19.

The POES series will reach end of life by 2022. It will be followed by the Joint Polar Satellite System Programme (JPSS).

Joint Polar Satellite System Programme

The JPSS is the new generation of polar orbiting environmental satellites. This is a collaborative program between US NOAA and NASA.

There are 3 operational satellites:

• Suomi National Polar-orbiting Partnership (S-NPP), launched in 2011
• NOAA‑20, formerly known as JPSS‑1, launched in 2017
• NOAA-21, known as JPSS-2, launched in 2023.

At our satellite data reception sites, we receive data from 3 different instruments on S-NPP, NOAA-20, and from mid 2024, NOAA-21:

• ATMS – Advanced Technology Microwave Sounder
• CrIS – Cross-track Infrared Sounder
• VIIRS – Visible/Infrared Imager Radiometer Suite.

EUMETSAT Polar System (EPS)

EUMETSAT operates 2 meteorological operational satellites (MetOp) under its EPS Programme:

• MetOp‑B
• MetOp‑C.

We receive data from these at our satellite data reception sites.

MetOp will be followed by the EPS Second Generation (EPS-SG) series. The first MetOp‑SG satellite is due to launch in 2024.

Receiving and processing satellite data

We have satellite data reception sites at:

• Melbourne, Victoria
• Darwin, Northern Territory
• Learmonth, Western Australia
• Casey and Davis stations in Antarctica.

Himawari 9 data is also provided through a dedicated fibre-optic line from Japan and a cloud-based internet service.

The receiving stations provide national imagery and processing for products relating to:

• solar radiation
• sea surface temperatures
• vegetation indices
• grassland curing
• atmospheric motion vectors
• volcanic ash
• atmospheric profiles of temperature and relative humidity
• numerical weather prediction models.

Receiving station ownership

The Bureau owns and operates 5 ground stations. We are also part of the Australian National Ground Segment Technical Team. This is a partnership with:

• Geoscience Australia
• Landgate – Satellite Remote Sensing Services
• CSIRO Space and Astronomy
• Australian Space Agency.

Direct Broadcast Network (DBNet)

The Bureau is the South Asia-Pacific coordinator for the World Meteorological Organization (WMO)'s Direct Broadcast Network.

DBNet is part of WMO's Space Programme. It aims to provide numerical weather prediction centres around the world with polar satellite products that have low data latency. This means that the products must arrive at all centres within 15–30 minutes after instrument sensing.

Our satellite receiving stations contribute data to this international effort.