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sc-mammo.txt
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1995-02-23
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PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
PHOTO CAPTION P-43891
April 13, 1994
Mammoth/C-band multipol
This image is a false-color composite of the Mammoth Mountain
area in the Sierra Nevada Mountains, California. The image is
centered at 37.6 degrees north latitude and 119.0 degrees west
longitude. The area is approximately 11.5 kilometers by 78.3
kilometers (7.2 by 48.7 miles) in size. The image was acquired
by the Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar
(SIR-C/X-SAR) aboard space shuttle Endeavour on its 40th orbit,
April 11, 1994. The city of Mammoth Lakes is visible in the
bottom right portion of the scene. In this color representation,
red is C-band HV-polarization, green is C-band VV-polarization
and blue is the ratio of C-band VV to C-band HV. Blue areas are
lakes or slopes facing away from the radar illumination. Yellow
represents areas of dry, old snow as well as slopes facing
directly the radar illumination.
At the time of the SIR-C overflight, the sky conditions were
partially cloudy, with low and cold air temperatures. Total snow
depth is about 1 to 1.5 meters (3 to 5 feet). The current snow
accumulation is only about 40 percent of the average for the
season. The most recent snowfall in the area covered the entire
area with about 30 centimeters (14 inches) of fresh dry snow.
Above 3,000 meters (10,000 feet) elevation the snowpack is dry.
Below that elevation, the snowpack has a layered structure.
Snow hydrologists are using SIR-C/X-SAR data to determine both
the quantity of water held by seasonal snowpack and the amount of
snow melting.
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SIR-C/X-SAR 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, in conjunction
with 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 fur Luft und Raumfahrt e.v. (DLR), the major
partner in science, operation and data processing of X-SAR.
#####