Fire monitoring in Armenia

What the monitoring shows

The MODIS and VIIRS satellite instruments observe Earth in visible and infrared wavelengths. Infrared channels are especially important for fire detection: the algorithm uses them to identify pixels that are significantly hotter than the surrounding surface. These points are called active fires or thermal anomalies.

MODIS, the Moderate Resolution Imaging Spectroradiometer, was developed as one of the main instruments in NASA's long-term Earth observation programme. The first instrument reached orbit aboard Terra in December 1999, followed by a second aboard Aqua in May 2002. MODIS observes not only fires but also clouds, aerosols, vegetation, snow, ice and the oceans. Its active-fire data has a resolution of about 1 km.

VIIRS, the Visible Infrared Imaging Radiometer Suite, continued this observation record with better sensitivity to smaller fires: its active-fire product has a resolution of about 375 m. The first VIIRS instrument was launched aboard Suomi NPP in October 2011. Similar instruments followed on NOAA-20, launched in November 2017, and NOAA-21, launched in November 2022. Because several satellites pass over the same area at different times, one fire can be detected repeatedly.

FIRMS was developed by the University of Maryland with support from NASA and the UN Food and Agriculture Organization. Its purpose is to turn satellite observations into an accessible active-fire map quickly. FIRMS publishes processed observations in near real time, but not instantly: several hours may pass between an overpass and a point appearing on the map.

What the parameters mean

• Detection time is the time when the satellite passed over the location.
• Confidence is the algorithm's estimate that helps distinguish reliable detections from uncertain ones.
• FRP is the fire radiative power within the detected pixel, expressed in megawatts. It indicates intensity, not fire area.
• Source is the satellite system that made the observation. VIIRS has a resolution of about 375 m, while MODIS has a resolution of about 1 km.

Important limitations

A point on the map is not an official confirmation of a fire. Industrial facilities, flares, hot surfaces or other heat sources can also produce a thermal anomaly. Clouds and smoke can sometimes prevent a satellite from detecting a fire.

Nearby detections are grouped, but a large or long-running fire may still form more than one group. Coordinates mark the average centre of a group's detections and do not show the exact fire boundary.

Sources and detailed documentation

• NASA FIRMS
• NASA FIRMS: Active Fire Data
• NASA FIRMS: MODIS Active Fire Data
• NASA: VIIRS Active Fire Product
• NASA Science: MODIS
• NOAA: VIIRS
• NOAA: JPSS Overview
• NASA Earthdata: FIRMS background