Fire is an important ecosystem disturbance with
varying return frequencies, resulting in land cover
alteration and change, and atmospheric emissions
on multiple time scales. Fire is also an important
land management practice and is an important
natural abiotic agent in fire dependent ecosystems.
Fires not only affect above-ground biomass but also
surface and below-ground organic matter such as
peat. Information on fire activity is used for global
change research, estimating atmospheric emissions
and developing periodic global and regional
assessments. It is also used for fire and ecosystem
management planning and operational purposes
(fire use, preparedness and wildfire suppression) and
development of informed policies.
The Fire Disturbance Essential Climate Variable
includes Burned Area as the primary variable and
two supplementary variables: Active Fire and Fire
Radiated Power (or Fire Radiative Power - FRP). Burned
Area is defined as the area affected by human-made
or natural fire and is expressed in units of area such as
hectare (ha) or square kilometre (km2). Active Fire is
the location of burning at the time of the observation
and is expressed in spatial coordinates or by an
indicator of presence of absence of fire in a spatially
explicit digital raster map, such as a satellite image.
FRP is the rate of emitted radiative energy by the fire
at the time of the observation and is expressed in
units of power, such as Watts (W).
Fire activity is a global phenomenon characterized
by strong spatial and temporal variability.
Documentation of fire activity by aerial means
(including manned or unmanned aircraft), such as
GPS plotting, post-fire photography or high resolution
radiometers, is done traditionally in some countries,
notably in Russia and other countries of the former
Soviet Union. However, declining fire management
budgets result in incomplete and inconsistent
coverage. Other countries that have limited fire
activity, e.g. Central European countries, are using
aerial patrols for early fire detection. Groundbased
observations from fire lookout towers or by
automated observing systems are also in place but
usually concentrated on limited areas of high-value
forests or nature reserves. Data from satellite remote
sensing are the most suitable and useful means for
large and global scale monitoring. Observing systems
have been developed using sensors on board both
polar orbiting and geostationary satellites.