Checking the ability of the K-line method to discriminate between smouldering and flaming activity in heather-dominated vegetation

Biomass burning affects the land and atmosphere through the combustion of vegetation and organic soils and transferring chemical constituents directly into the lower atmosphere. Understanding the impacts of global biomass burning on the terrestrial biosphere, atmosphere and their change over time are the main scientific questions.At local scale, fires are a major security hazard which affect vegetated resources and settlements. Within Europe, Mediterranean countries are the most affected by vegetation fires, with an average of almost 50 000 between 1980 and 2008 and an estimated total cost of around 1% of Domestic Product (WFC 2009). This includes the cost of firefighting organisations, fire insurance administration and the protection to buildings .It is important to be able to detect small fires that may be important as precursors to larger burns, and as predictors of fire spread when incorporated into operational fire models. Data collected remotely by sensors on satellites or aircraft at shortwave infrared and thermal infrared wavelengths are traditionally used, although such instruments are often costly and difficult to operate from traditional airborne platforms. Until now, the use of hyperspectral techniques (imaging using many very narrow wavebands) has been limited by the cost and weight of instruments. The recent growth in the unmanned aerial vehicle (UAV) market has led to the development of light and relatively cheap instruments, including hyperspectral sensors in the visible to invisible near infrared (VINIR). Hyperspectral sensors can be used to detect small active fires, and especially to discriminate between flaming and smouldering combustion. They can also be used to monitor the regeneration of vegetation on burn scars. In this study, we investigate the suitability of a technique called Potassium (K)-line emission to distinguish between flaming and smouldering combustion for an experimental fire in heather.