Satellite remote sensing for early detection of forest fires
The detection of forest fires by means of Earth observation is based on the exploitation of multispectral and infrared data from satellite constellations in low and medium orbit. Short-wave infrared (SWIR) and thermal infrared (TIR) sensors make it possible to identify radiometric anomalies associated with active hotspots, with revisit times that, in small-satellite constellations, can fall below one hour. The integration of these data with vegetation indices derived from the visible and near-infrared spectrum, such as the NDVI, provides a characterisation of the state of the vegetation cover that directly conditions vulnerability to fire. This spectral-layer fusion approach underpins early-warning architectures such as the FIPAS project, funded by EIT Climate-KIC in collaboration with the Finnova Foundation and the municipality of Pehchevo, in North Macedonia. From an operational standpoint, the processing chain involves the reception and atmospheric correction of imagery, the application of hotspot detection algorithms, and the generation of geolocated alerts with an associated confidence level. The total latency between data acquisition and notification to the emergency manager is a critical system design parameter. Level-2 products from missions such as Sentinel-3, or VIIRS data aboard the Suomi NPP and JPSS satellites, offer global coverage with temporal resolution adequate for detection, albeit with moderate spatial resolution. For high-priority areas, combining these with higher spatial resolution imagery on scheduled passes improves the characterisation of the active perimeter. The limitations of the satellite-based approach are physical and operational in nature. Cloud cover blocks the thermal signal in the infrared bands, which can interrupt the detection chain under adverse meteorological conditions. Likewise, the temporal resolution of optical observation satellites does not guarantee continuous coverage, introducing windows of uncertainty between successive passes. In this context, the integration of satellite data with ground sensor networks and unmanned aerial platforms constitutes an operational redundancy strategy that emergency management systems must incorporate into their data fusion architecture. In the regulatory and governance domain, the use of Earth observation data for natural risk management falls within the Copernicus Emergency Management Service, which establishes activation protocols and the delivery of cartographic products to competent authorities. The scalability of systems such as FIPAS to other municipalities or regions with a similar risk profile depends on the availability of local reception and processing infrastructure, as well as on the training of operators in the interpretation of remote sensing products applied to decision-making in fire emergencies.
NASSAT - Network Satellite Systems