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FROM NASA/JPL
PRESS
RELEASES
June 20, 1999: NASA's Quick Scatterometer (QuikScat)
was lofted into space at 7:15 p.m. Pacific Daylight Time
yesterday atop a U.S.
Air Force Titan II rocket from
the Vandenberg Air Force Base in California.
The satellite was launched in a south-southwesterly direction, soaring over the Pacific Ocean at sunset as it
ascended into
Earth orbit. [More launch details]
Right: QuickScat's predecessor,
NSCAT, a microwave radar
scatterometer, measured
near-surface wind vectors (both
speed and direction) over the global
oceans starting in August 1996.
The SeaWinds on QuikSCAT mission is a
"quick recovery" mission to fill the gap created
by the loss of data from the NASA
Scatterometer (NSCAT), when the satellite it
was flying on lost power in June 1997. [More information] Photo Credit: JPL
Built in record time in just 12 months,
QuikScat will provide climatologists, meteorologists and oceanographers with daily,
detailed snapshots of ocean winds as they swirl above the world's oceans. This satellite will be
NASA's next "El Niņo watcher." It will be used to better understand global
weather abnormalities and to generally improve weather forecasting.
Winds play a major role in every aspect of weather on Earth. They directly affect the turbulent exchanges of heat,
moisture and greenhouse gases between Earth's atmosphere and the ocean. To better understand their impact on oceans
and improve weather forecasting, the satellite carries a state-of-the-art radar instrument called a scatterometer for a
two-year science mission.
"Knowledge about which way the wind blows and how hard is it blowing may seem simple, but this kind of
information is actually a critical tool in improved weather forecasting, early storm detection and identifying subtle changes
in global climate," said Dr. Ghassem Asrar, associate administrator of NASA's Office of Earth Science, Washington, DC.
The mission will help Earth scientists determine the location, structure and strength of severe marine storms -
hurricanes in the Atlantic, typhoons near Asia and mid-latitude cyclones worldwide - which are among the most
destructive of all natural phenomena. The National Oceanic and Atmospheric Administration (NOAA), a chief partner in
the QuikScat mission, will use mission data for improved weather forecasting and storm warning, helping forecasters to
more accurately determine the paths and intensities of tropical storms and hurricanes.
As NASA's next "El Niņo watcher," QuikScat will be used to better understand global El Niņo and La Niņa weather
abnormalities. Changes in the winds over the equatorial Pacific Ocean are a key component of the El Niņo/La Niņa
phenomenon. QuikScat will be able to track changes in the trade winds along the equator.
Left:
TOPEX/Poseidon's sea-surface height measurements have provided
scientists with a detailed view of the 1998-99 La Niņa and
the 1997-98 El Niņo because the satellite's altimeter measures
the changing sea-surface height with unprecedented precision.
In this image, which shows the lingering effects of La Nina in May 1999,
the purple areas are about 18 centimeters
(7 inches) below normal, creating a deficit in the heat
supply to the surface waters. The white areas show the sea surface is between 14 and 32 centimeters (6 to 13 inches) above normal; in the red areas, it's about 10 centimeters (4 inches) above normal.
Changes in the winds over the equatorial Pacific Ocean are a key
component of the El Niņo/La Niņa
phenomenon. QuikScat will be able to track changes in
the trade winds along the equator and, thus, complement data
from NASA's other Earth-watching satellites.
Photo Credit: JPL
Scatterometers operate by transmitting high-frequency microwave pulses to the ocean surface and measuring the
"backscattered" or echoed radar pulses bounced back to the satellite. The instrument senses ripples caused by winds near
the ocean's surface, from which scientists can compute the winds' speed and direction. The instruments can acquire
hundreds of times more observations of surface wind velocity each day than can ships and buoys, and are the only
remote-sensing systems able to provide continuous, accurate and high-resolution measurements of both wind speeds and
direction regardless of weather conditions.
The satellite is the first obtained under NASA's Indefinite Delivery/Indefinite Quantity program for rapid delivery of
satellite core systems. The procurement method provides NASA with a faster, better and cheaper method for the
purchase of satellite systems through a "catalog," allowing for shorter turnaround time from mission conception to launch.
Total mission cost for QuikScat is $93 million.
Fifteen times a day, the satellite will beam down collected science data to NASA ground stations, which will relay
them to scientists and weather forecasters. SeaWinds will provide ocean wind coverage to an international team of climate
specialists, oceanographers and meteorologists interested in discovering the secrets of climate patterns and improving the
speed with which emergency preparedness agencies can respond to fast-moving weather fronts, floods, hurricanes,
tsunamis and other natural disasters.
By combining QuikScat's wind data with information on ocean height from another ocean-observing satellite, the joint
NASA- French TOPEX/Poseidon mission, scientists will be able to obtain a more complete, near-real-time look at wind
patterns and their effects on ocean waves and currents, said Dr. Timothy Liu, QuikScat project scientist at NASA's Jet
Propulsion Laboratory, Pasadena, CA. He added that QuikScat will complement data being collected by other
Earth-monitoring satellites such as NASA's currently orbiting Tropical Rain Measurement Mission (TRMM) and Terra,
which will be launched later this year.
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