Assessment of grassland curing using field-based spectrometry and satellite imagery

Depending on a grass's growth stage, certain curing characteristics determine the vulnerability of grass to ignite or to propagate a fire. The current curing input into fire behaviour models and fire danger rating systems in Australia and New Zealand is generally based on visual estimates, which are widely recognised by both researchers and end-users as being inaccurate and thus causing uncertainty in system outputs. This Bushfire Cooperative Research Centre (CRC) project aims to develop improved methods to assess grassland curing across Australia and New Zealand. This paper reports on one component of the CRC project, which has focused initially on vegetation indices derived from EOS MODIS (MODerate resolution Imaging Spectroradiometer) satellite data. Results suggest a positive correlation between these satellite data and field data for curing assessment.Methods include destructive sampling, visual observations and Levy rod sampling. More comprehensive field data collection has been conducted in Victoria, entailing measurements of spectral reflectance signatures of grasslands using an ASD Fieldspec Spectroradiometer covering the wavelength range 350-2500 nm. These measurements identify which regions of the visible to mid-infrared spectrum best correlate with field data collected for curing assessment. The information produced from this project will lead to improved assessments of the degree of curing in grasslands across Australia and New Zealand, thereby providing sound science to support fire management in protecting life and property from grassfires, as well as using fire safely and effectively