PC Media 4/PC MEDIA CD04.iso/nasa/sc-mland.txt

Text File | 1995-02-23 | 4KB | 72 lines

PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA 91109. TELEPHONE [phone]

PHOTO CAPTION                                             P-43924
                                                   April 16, 1994
                                           Mammoth land cover map

These two images were created using data from the Spaceborne
Imaging Radar C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR).
The image on the left is a false-color composite of the Mammoth
Mountain area in California's Sierra Nevada Mountains centered at
37.6 degrees north, 119.0 degrees west.  It was acquired onboard
space shuttle Endeavour on its 67th orbit on April 13, 1994.  In
the image on the left, red is C-band HV-polarization, green is C-
band HH-polarization and blue is the ratio of C-band VV-
polarization to C-band HV-polarization.  On the right is a
classification map of the surface features which was developed by
SIR-C/X-SAR science team members at the University of California,
Santa Barbara.  The area is about 23 by 46 kilometers (14 by 29
miles).  In the classification image, the colors represent the
following surfaces:

  White          snow
  Red            frozen lake, covered by snow
  Brown          bare ground
  Blue           lake (open water)
  Yellow         short vegetation (mainly brush)
  Green          sparse forest
  Dark green     dense forest

Maps like this one are helpful to scientists studying snow
wettness and snow water equivelent in the snow pack.  Across the
globe, over major portions of the middle and high latitudes, and
at high elevations in the tropical latitudes, snow and alpine
glaciers are the largest contributors to run-off in rivers and to
ground-water recharge.  Snow hydrologists are using radar in an
attempt to estimate both the quantity of water held by seasonal
snow packs and the timing of snow melt.  Snow and ice also play
important roles in regional climates; understanding the processes
in seasonal snow cover is also important for studies of the
chemical balance of alpine drainage basins.  SIR-C/X-SAR is a
powerful tool because it is sensitive to most snow pack
conditions and is less influenced by weather conditions than
other remote sensing instruments, such as the Landsat satellite.

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Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar
(SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The
radars illuminate Earth with microwaves allowing detailed
observations at any time, regardless of weather or sunlight
conditions. SIR-C/X-SAR uses three microwave wavelengths:  L-band
(24 cm), C-band (6 cm) and X-band (3 cm).  The multi-frequency
data will be used by the international scientific community to
better understand the global environment and how it is changing.
The SIR-C/X-SAR data, complemented by aircraft and ground
studies, will give scientists clearer insights into those
environmental changes which are caused by nature and those
changes which are induced by human activity.  SIR-C was developed
by NASA's Jet Propulsion Laboratory. X-SAR was developed by the
Dornier and Alenia Spazio companies for the German space agency,
Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the
Italian space agency, Agenzia Spaziale Italiana (ASI), with the
Deutsche Forschungsanstalt fuer Luft und Raumfahrt e.v. (DLR),
the major partner in science, operations and data processing of
X-SAR.

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