Roughly 438 miles (705 km) above the Earth, the Moderate Resolution Imaging
Spectroradiometer (MODIS) instrument aboard NASA’s Aqua satellite opened
its Earth-view door on June 24 and took its first look at our planet. The above
image was taken by the MODIS instrument on August 12, 2002, a month and a half
after “first light.”
The image shows the Biscuit Fire, formed by the convergence of the
Florence Fire and the Sour Biscuit Fire.
The fire was sparked by lightning in the Klamath
Mountains in Oregon and has burned over the state line into California,
consuming over 375,000 acres as of August 14th, 2002. Actively burning
areas are marked with red outlines.
Like its twin launched aboard NASA’s Terra satellite in 1999, Aqua MODIS
sees almost the entire surface of our planet every day in 36 channels ranging
from visible to thermal infrared wavelengths. On a daily basis, Terra descends
across the equator at 10:30 a.m. local time, while Aqua ascends across
the equator at 1:30 p.m.
With the launch of the Aqua instrument, scientists will be able to conduct the
most comprehensive daily examination of our planet by combining data from two
MODIS instruments on sister satellites in Earth’s orbit. Researchers will be
able to observe land, ocean, and atmospheric phenomena in the afternoon with
Aqua and in the morning with Terra. The instrument will make it possible to
observe rapid, time-varying phenomena like clouds, water vapor, and fire. The
different timing of the satellites’ pole-to-pole orbits enables scientists
to focus on different aspects of the Earth’s climate system and to see
changes within the system during the course of a day.
Among other things, Aqua MODIS will dramatically improve scientists’
ability to monitor the daily cycles of the large-scale burning of
plant biomass in regions all across the planet. Scientists
will be able to better sample fire activity and improve their
chances of obtaining cloud free observations of the surface. With such coverage, researchers
can gather more data on how fast and in which direction fires are spreading as
well as information on how severely a given fire may affect air quality of
downwind urban areas.