Between two banks of clouds, a pall of gray smoke hangs above the Amazon
rainforest in this image that illustrates how complex interactions between
smoke and the atmosphere can influence weather and climate. Few clouds are
present in the smoke between the cloud banks. Dark soot particles in the
smoke absorb sunlight, which heats up the surrounding air. Water vapor is
more likely to condense into liquid water droplets—clouds—in cooler air,
so clouds are less likely to form in areas with smoke-warmed air. As a
result, fires in the Amazon reduce cloud cover.
The Mediterranean Israeli Dust Experiment (MEIDEX), an instrument that
flew aboard Space Shuttle Columbia’s final flight from January 16 to
February 1, 2003, acquired this image and measured smoke and other types
of aerosols from the Shuttle’s
payload bay. MEIDEX also observed a dust
storm that originated in the Sahara Desert and carried dust over the
Mediterranean Sea. This is a false-color image in which clouds appear
white, smoke appears gray, and the Amazon Rainforest appears red.
Several instruments aboard Space Shuttle Columbia, including MEIDEX, were
designed to study the Earth from above. Instruments aboard manned spacecraft
like the Space Shuttle and International Space Station form an important
complement to orbiting satellites and ground-based measurements. Once a
satellite is launched into orbit, scientists are limited in their ability to
measure exactly how the instrument is changing or degrading over time.
Instruments flying aboard the shuttle can be calibrated before and after
launch, so their measurements can be more accurate than those from
satellites. Using the shuttle instruments to collect observations similar to
those made by long-term satellite missions permits scientists to monitor an
aging satellite’s accuracy over time. Shuttle-carried instruments are
relatively inexpensive because they utilize the Shuttle’s power, data, and
communications equipment. Astronauts are also able to aim the sensors
aboard, enabling them to capture unique and unpredictable events.