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| Rural Industries |
Objectives
Background
Vegetation systems, by feeding our population, moderating our climate, assimilating our waste and providing a major sink for fossil fuel CO 2 , play a critical role in modulating whole-earth responses under increasing population pressure and climate change. By virtue of their capacity to regenerate, after-use vegetation systems are renewable resources that are essential for ecologically sustainable development. However persistent mismanagement of these systems continues to contribute to major land and environmental degradation.
Research
Green vegetation cover was measured by the difference between near infrared and visible reflectance divided by their sum to give the Normalised Difference Vegetation Index (NDVI). The individual reflectances and thermal infrared temperatures were used for other purposes such as fire scar mapping.
Outcome
A largely automatic end-to-end system for the routine
processing of AA-AVHRR satellite data into a number of image products
was developed.
The Bus Fires Board successfully deployed fire fighting
resources in areas of fuel load build up identified from the NDVI
images. Improved forecasts of fire risk were made in the south-west
using estimates of fuel flammability based on estimates of grassland
curing from the decline in NDVI.
The Department of Agriculture, Western Australia
and Northern Territory Department of Primary Industry successfully
used the time series of NDVI from 1991 to 1995 to advise Government
of the major drought affected areas in 1994. WATBAL estimates
proved unreliable because pastoralists often corrupt their rainfall
records to produce an outcome in their favour. The time series
were also incorporated into DAWA's pastoral lease report to the
Western Australian Pastoral Board to provide a more accurate assessment
of seasonal conditions and were seen as a method for providing
tactical advice on stocking rates by regional officers.
Significant correlations of the NDVI between July and September with final wheat yields, indicated the potential for use in crop forecasting in agricultural areas.
Implications
Successful use of the NDVI time series and images
for such management and forecasting tasks requires a high level
of quality control to remove the not insignificant effects of
trends caused by changes in the AVHRR sensor and from cloud effects.
Accurate interpretation of the changes in NDVI requires
integration with other geographic information sets. The wide range
of applications in near real-time NDVI indicates that this is
now a novel source of information of changes in green vegetation
cover.
RIRDC Project No: DOL-1A
RESEARCHER: Dr Richard C.G. Smith
ORGANISATION: Remote Sensing Applications Centre,
WA Department of Land Administration PO Box 471 WEMBLEY WA 6014PHONE: 09 240 9342
FAX: 09 383 7142PUBLICATIONS:
Smith, R C G, Adams, J, Stephens, D J and Hick, P T (1995). Forecasting wheat yield in a Mediterranean type Environment from the AA satellite. Aust. J. Agric. Res. 46 113-25.
Last updated: 10 October 1996
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