NOAA Data and Applications

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NOAA HRPT Data

NOAA Polar orbiting satellites pass over the poles at aproximately 850 km. The whole surface of the earth is observed by these satellites, which follow nearly fixed orbits while the earth rotates beneath them. The area scanned by each pass (swath) are nearly adjacent at the equator on consecutive passes. Further polewards the passes progressively overlap. The swaths are usually about 2600 km wide, and by completing 14 orbits a day one satellite can provide a complete cover of the globe twice every 24 hours. The radiometer points continuously at the earth (Earth Stabilized) and images are built up by a mirror on the satellite scanning from side to side at right angles to the orbit path. High Resolution Picture Transmission ( HRPT ) data is transmitted continuously and can be picked up at reception sites within range of the satellite. Reduced resolution Global Area Coverage (GAC) data is stored for later transition to NOAA. The Bureau's main reception site is Crib Point (80km SE of Melbourne), with additional sites at Casey, Davis, Darwin and Perth.

Current location of NOAA-12, -14, -15, -16, -17 and -18

These stations provide national coverage of imagery and processed products in support of Bureau's analysis and forecasting service and also provide data for more detailed studies of climate and climate related disciplines. All five stations are operated by the Bureau. However the three stations located at Crib Point, Darwin, Davis and Casey are owned solely by the Bureau whilst the Perth station is owned by the Western Australian Satellite Technology and Applications Consortium (WASTAC) which consists of The Bureau of Meteorology, Curtin University of Technology, CSIRO Office of Space Science and Applications (COSSA) and the West Australian Government's Department of Land Administration.

At each station NOAA HRPT data is archived in real time using the Australian Standard Data Archive (ASDA) format (developed by Bureau and CSIRO, Turner et al 1996) and is also split into its components for processing (c.f. Planet 1979).

The Advanced Very High Resolution Radiometer (AVHRR) data are processed into Man-computer Interactive Data Access System (McIDAS) area files (up to about 120 Mbytes per orbit).

The main operational value added products or applications generated by the Bureau using data from its national HRPT network are as follows:

TOVS Retrievals

A physical TOVS retrieval scheme (Le Marshall et al. 1989) , developed for local use, generates vertical profiles of atmospheric temperature and moisture and total ozone estimates. These data are assimilated directly into numerical weather prediction (NWP) models and contribute to improved accuracy. More recently, the Bureau has been producing similar data from the Advanced TOVS (ATOVS) system on NOAA-15.

Sea Surface Temperatures (SST)

The Bureau produces national SST mosaics in real time on a 3 x 3 grid using a heavily modified, multichannel scheme originally based on McClain et al.(1985). These data form the basis of a real time analysis assimilated into NWP models.

Samples of regional SST maps:

[About SSTs]

[Subscription Service: State, Australian Region and Global SST Products ]

Grass Land Curing Index (GCI) and Normalised Difference Vegetation Indices (NDVI)

NDVI maps are derived covering Australia and involve a maximum value composite method (Tuddenham et al.1994). The data are used to monitor monthly changes in vegetation and other drought/climate related matters; flood monitoring; fire scars; as input in fireweather forecasting via generation of grassland curing indicator (GCI). The work is part of a collaborative agreement with CSIRO Atmospheric Research and is contributing to a coordinated national strategy to enhance information for fire weather management.

[About: NDVI and GCI ]

Sea Ice Monitoring

The Bureau's Tasmania/Antarctica Regional Office coordinates Bureau activities and services for Antarctic expeditions and one valuable source of information is the Casey HRPT station. In particular, real time data are used in weather forecasting and in monitoring the location and movement of sea ice. The Bureau works closely with the CRC for Antarctica and the Southern Ocean in Hobart, which uses Casey HRPT data in research studies.

Samples of AVHRR Antarctic Sea Ice Images :

[Subscription Service Sea Ice Imagery ]

Low Cloud/Fog Detection

Algorithms using AVHRR Channel 3 and 4 in particular are used to detect fog or low cloud especially at night or before sunrise because contrast enhanced visible imagery is only useable when scenes are sunlight illuminated. Fog and low cloud are important in aviation weather services.

Bushfire Monitoring (Hotspots and Smoke)

The Bureau is also developing algorithms for the detection of bushfires. The "coarse" 1km data is useful for finding fire lines through dense smoke where conventional aircraft scans fail.Specially enhanced multiband AVHRR imagery is used in real time to monitor hotspots from bushfires (channel 3) and smoke (channels 1,2 and 4 composites) during the Australian summer. Since September 1997, Darwin AVHRR data has been used continuously to monitor the location and extent of fires over Indonesia and Papua New Guinea

Volcanic Ash Detection

The Bureau's Northern Territory Regional Office runs a Volcanic Ash Advisory Centre as part of a global network to provide warnings of ash clouds which are a serious threat to aviation. There are many volcanoes to the north of Australia and Darwin AVHRR data is used in real time, especially Channels 4 and 5, to complement other data in monitoring ash cloud movement and dispersal.

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