What are the Benefits and Challenges of using SAR Data to Detect and Monitor Burn Scars in Peat Moorlands?

A systematic, landscape-scale method of detecting wildfire burn scars in peat moorlands would improve recording of burned area and monitoring of regeneration and restoration. Cloud cover means that optical satellite data is often unavailable in the UK. Thermal sensors can only map burn scars whilst they emit heat. Synthetic Aperture Radar (SAR) sensors on satellites (e.g. ASAR, ERS-2, PALSAR) are an alternative, all-weather remote sensing method for detecting and monitoring burn scars in a degraded peat moorland environment like the Peak District National Park (PDNP). SAR sensors send out pulses of microwave energy which are scattered by the ground back towards the same sensor to generate an image. Burn scars in peat moorland can be detected because fire changes the surface roughness and wetness, which affects image brightness (intensity of backscattered energy). We studied how these changes in intensity relate to environmental variables such as precipitation and land cover, and different radar wavelengths, in order to recommend optimum conditions for imaging. The Bleaklow 2003 and Edale 2008 burn scars are used to show the benefits and challenges of using a time series of radar data. SAR can detect peat moorland burn scars several months after a wildfire event, especially when post-fire images are acquired during a wet period.