Land and Water Link
Issue No. 12, May 2002
Disasters - Seeing the Big Picture
Last Christmas as the first of the bushfires roared through forests and
destroyed homes in New South Wales, CSIRO researchers worked quickly to
show a bigger and better picture of the disaster as it unfolded.
They created highly detailed satellite images of the fires that burnt
beneath the smoke plumes up and down the coast of New South Wales. While
emergency services and the media focused on the fires in that State, the
scientists could also see large fires burning in Western Australia and
the Northern Territory.
Alex Held and Alan Marks of the Environmental Remote Sensing Group at
CSIRO Land and Water in Canberra created fire maps using data from a US-owned
satellite. It was launched into space in late 1999 by the National
Aeronautics and Space Administration (NASA) and carries an advanced
sensor called a Moderate Resolution Imaging Spectrometer (MODIS).
The CSIRO Land and Water group works with other CSIRO researchers to develop
new ways of using MODIS data for a variety of applications including the
monitoring of coastal water quality and crop conditions.
The Christmas fires however, became a test run for how quickly this data
could be downloaded by receiving stations operated by the Australian Centre
for Remote Sensing (ACRES) and delivered to emergency services.
MODIS orbits earth and records reflected light (colour and intensity)
from everywhere around the world every 1-2 days. The data it generates
has a combination of features that makes it particularly useful for tracking
large-scale disasters in Australia. For example, nearly every day MODIS
takes snapshots of the same places in Australia as it passes overhead
and each snapshot covers a very large area.
From 700 kilometres above the earth it can 'zoom in' on an area as small
as 250 m x 250 m and record the reflected 'colours' in 36 wavelengths,
including the surface temperature. So even when smoke or clouds obscured
the fires burning in NSW, MODIS still detected many of the hotspots because
it could pick up heat differences. The greater sensitivity of the MODIS
sensor is also expected to provide fire maps that are better at showing
smaller and cooler fires, compared to those produced from more traditional
satellite data.
Alex Held and his team used the MODIS data to track the fire fronts day-by-day
through December and January, and emailed fire maps to relevant agencies.
'The images spoke a thousand words – they gave a clear and detailed
overview of the whole situation in New South Wales', he says.
'We demonstrated that the MODIS sensor, combined with other satellite
sensors used by colleagues in CSIRO and the Department of Land Administration
in WA, can provide almost real-time fire monitoring from space.'
'It is clear that maps derived from such satellite data could be equally
useful if other large-scale disasters like floods, cyclones and coastal
oil spills hit Australia', predicts Alex Held.
For further information:
Contact
Dr Alex Held
Ph: 02 6246 718
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