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NASA Reports
Concerning Air & Oxygen
Source
Earth
Science Gallery
TOP EARTH EVENTS
SEEN BY SEAWIFS (5-YEAR ANNIVERSARY) (GSFC, G02-061, 7/31/02)
Right now, tiny
single-celled sea plants called phytoplankton produce almost half
the oxygen you breathe.
With the launch of the Sea-viewing
Wide fField-of-view Sensor (SeaWiFS) five years ago on board the
Orbview 2 satellite, scientists have a new tool for studying how
these plants interact with the world. Their discoveries are
revolutionizing our understanding of our planet.
RAIN REACTION
Rain, be it gentle or punishing,
impacted lives, crops, oceans, lands, and air in 2002. NASA's Earth
Scientists kept their eyes on these influences, aiming to understand
the interactions and predict short- and long-term changes from rain.
Text of Reporter Package
- Whatever the weather, NASA's paying close attention. While El Nino
and La Nina made themselves scarce in 2002, their legacy of extreme
weather remained.
The space agency's Earth
scientists tracked droughts and floods, hurricanes and heavy rains,
lost lives and billion-dollar damage. Their goal: decipher causes of
extreme weather, including rainfall's role in the planet's changing
climate. In 2002, Earth scientists linked two factors to increased
rain: cities and soot. Urban areas concentrate artificial surfaces
and soot into heat-absorbing centers. Trapped heat alters regional
air currents over cities. Warm air rises over cities, increasing
clouds and rainfall, both locally and downwind. As a result, cold
air moves in to upwind areas, inhibiting rainfall there, often to
the point of drought.
Why is this important? For one
thing, changes in rainfall patterns impact plant growth. Scientists
know droughts deprive plants of necessary water. But less obviously,
too much rain hurts crops as well.
Heavy rains saturate soil,
interfering with root growth, leading to crop losses.
Within 30 years, U.S. agricultural
losses from extreme rain could double to $3 billion annually if
current rainfall predictions prove accurate.
Fewer plants could
worsen the problem of excess rain, starting a vicious cycle. As
plants grow, they take in carbon dioxide and give off oxygen. Fewer
plants mean more carbon dioxide in the air. Carbon dioxide, like
soot, absorbs the Sun's heat and causes even more rain.
But NASA scientists have been
developing tools to foresee these climatic events. The El Nino
Prediction Index tracks changes in rainfall patterns in the Indian
Ocean, aiming to give forecasters months of notice for big events.
Coupled with new knowledge of how precipitation impacts climate,
policy makers can better plan water usage and crop planting. Armed
with information, NASA watches the rain for El Nino's imminent
return.
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