Geostationary Imagers Revisit the Same Ground Every Few Minutes
A geostationary satellite hangs over one longitude and stares at the same hemisphere continuously, so its imager can repeat an observation of a given place on a timescale of minutes rather than twice a day. The Advanced Baseline Imager on the GOES-R series scans the full disk every ten minutes and can run a contiguous regional sector every five minutes, or a small mesoscale sector every minute, and it carries the midwave infrared channel needed for fire detection. That cadence changes what a satellite can be used for: growth becomes visible as a sequence rather than inferred between passes, an ignition can be timed to within minutes, and a rapid run can be watched while it happens. The cost is written into the orbit. From 36,000 kilometres the fire pixel is about 2 kilometres at nadir and considerably larger at high latitudes and toward the limb, so only substantially more intense fires are detected than a 375-metre polar-orbiting pixel would find. After this Concept you can say what a geostationary fire product adds to a polar-orbiting one and what size of fire it will simply miss.
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A geostationary satellite hangs over one longitude and stares at the same hemisphere continuously, so its imager can repeat an observation of a given place on a timescale of minutes rather than twice a day. The Advanced Baseline Imager on the GOES-R series scans the full disk every ten minutes and can run a contiguous regional sector every five minutes, or a small mesoscale sector every minute, and it carries the midwave infrared channel needed for fire detection. That cadence changes what a satellite can be used for: growth becomes visible as a sequence rather than inferred between passes, an ignition can be timed to within minutes, and a rapid run can be watched while it happens. The cost is written into the orbit. From 36,000 kilometres the fire pixel is about 2 kilometres at nadir and considerably larger at high latitudes and toward the limb, so only substantially more intense fires are detected than a 375-metre polar-orbiting pixel would find. After this Concept you can say what a geostationary fire product adds to a polar-orbiting one and what size of fire it will simply miss.
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