Development of satellite vegetation indices to assess grassland curing across Australia and New Zealand

Grasslands, including woodlands, grass and scrub mixes, cover nearly 75% of Australia and constitute 70% of vegetation cover in New Zealand. Grass characteristics such as water content and degree of curing (senescence), determine the vulnerability of grasses to propagate and carry fire. This work is part of a Bushfire Cooperative Research Centre (CRC) project that aims to improve the assessment and prediction of grassland curing across Australia and New Zealand. This will be carried out with the use of two satellite remote sensors. NOAA AVHRR has been used operationally to produce a satellite curing index since the 1980s across southeastern Australia. In the near future, the use of this sensor will be extended across the continent on the basis of extensive field data collected by the CRC. The EOS MODIS sensor, can provide more detailed assessments of vegetation than AVHRR, and has the potential to provide better curing estimates due to its greater number of spectral bands. The aim of this project is to develop a satellite-based method for curing assessment that is robust and can be validated across Australia and New Zealand. This paper covers the background research of satellite remote sensing on grassland curing, and presents preliminary methods and results using field data and MODIS-derived vegetation indices.