Roughly 438 miles 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. This event, called “first light,” marks a milestone in Earth
observation, allowing scientists to conduct the most comprehensive
daily examination of our planet by combining data from two MODIS
instruments on sister satellites in Earth orbit.

Like its twin flying aboard NASA’s Terra satellite — launched 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. in every
time zone, while Aqua ascends across the equator at 1:30 p.m. in every
time zone. 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.

“With the launch of Aqua,” said MODIS Team Leader Vince Salomonson, of
NASA’s Goddard Space Flight Center, Greenbelt, Md., “we are able to
observe land, ocean and atmosphere phenomena in the afternoon with Aqua
and in the morning with Terra. This is especially important for
observing rapid, time-varying phenomena like clouds and water vapor.”

Understanding the processes of water evaporation, the movements of
water vapor (the dominant greenhouse gas) throughout the atmosphere —
and the relationship of these processes to cloud formation — is
essential to climate and local weather modeling.

In its first day of operations, Aqua MODIS observed significant Earth
events occurring all over the globe. Even as Super Typhoon Chataan was
rapidly approaching Japan, there was severe flooding in southeast
Texas, and a vast, thick pall of smoke from Canadian wildfires
blanketed almost the entire U.S. East Coast. MODIS collected and beamed
to Earth these images in very-near real time.

Data from Aqua MODIS will augment scientists’ ability to track wind and
clouds in the polar regions where current weather satellites can’t see,
helping meteorologists to better monitor and predict global weather

Aqua MODIS will also dramatically improve scientists’ ability to
monitor the daily (diurnal) cycles of the large-scale burning of plant
biomass in regions all across the planet. “Aqua MODIS will complement
Terra, providing four observations per day that will better sample the
daily cycle of fire activity and provide increased opportunity of
cloud-free observations,” said Chris Justice, the MODIS Land Team
Leader at the University of Maryland, College Park. Using Aqua MODIS,
scientists can gather more data on how fast and in which direction
fires are spreading, as well as how severely a given fire may affect
air quality of downwind urban areas.

Aqua MODIS data have worldwide applications. The MODIS team is working
with the Global Observation of Forest Cover/Gold-Fire Program and the
World Fire Monitoring Center to provide fire data to the international
community. Team members collaborate with fire monitoring groups in
Australia, Botswana, Brazil, Malaysia, Mexico and Russia.

Having a second MODIS instrument will also improve ocean-based
research. “Aqua will provide continuity of important observations of
sea surface temperature and ocean color, which is a marker of the
biochemistry of marine organisms,” Salomonson added.

Aqua and Terra each carry a MODIS instrument designed to gather
planetary data across 36 spectral bands. Data will be processed into 44
distinct data products available to the world for use in tracking
global climate change.

The satellites are part of NASA’s Earth Science Enterprise, a long-term
research effort to understand and protect our home planet. Through the
study of the Earth, NASA will help provide sound science to policy and
economic decision-makers to improve life here, while developing the
technologies needed to explore the universe and search for life beyond
our home planet.

For more information and images, see:

For the more on the MODIS Instrument, go to: