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NASA GSFC's Radar Ocean Wave Spectrometer (ROWS) is an airborne remote
sensor used to support the development and refinement of satellite
radars that measure the ocean surface. The short-pulse Ku-band radar
is specifically configured to measure the directional spectrum of
ocean swell. In addition, the system is being used to study near-nadir
ocean backscatter and its relation to wind waves. The sensor is
typically flown on one of several NASA aircraft and is potentially
available for outside use in funded ocean research efforts. Currently,
ROWS research efforts are aimed at improving the interpretation of
ocean data collected using the satellite SAR (ERS-1), altimeter(TOPEX)
and scatterometer (NSCAT).
The airborne system has participated in numerous ocean surface
measurement programs since since the late 1970s. ROWS has been
installed on numerous aircraft, most recently NASA/GSFC/WFF's T-39 and
P-3B. The system is typically operated from altitudes of 5-10 km.
The high-range-resolution radar generates data using two distinct,
continuously-operating modes. Spectrometer mode data are collected
with a near-vertically-pointing, pencil-beam antenna which rotates in
azimuth. These data are used to derive two- dimensional ocean wave
spectral estimates and near-nadir directional radar backscatter
information. Concurrent pulse-limited altimeter mode radar returns are
derived using a vertically-pointed horn antenna. Ocean significant
wave height and surface wind speed are inferred from the altimeter
return. A table below provides the radar system's characteristics.
ROWS Instrument Characteristics
Frequency 13.9 Ghz
Pulse Type linear FM, 100 MHz bandwidth,1.2 us chirp
Pulse length 12.5 n, compressed
Peak power 2 kW
PRF 100 Hz
Dynamic range 70 dB
Detection noncoherent, square law
Antennas
A)10 by 40 (elevation by azimuth)printed circuit array,
vertical polarization,16 deg. boresight,6 rpm rotation rate
B)vertically-pointing 290 pyramidal horn
Data system
PC-based with full waveform capture using a 100 or 500 MHz
digitization rate
For more information on ROWS see:
"http://rows.wff.nasa.gov/"
For information on the ROWS Project see:
"http://rows.wff.nasa.gov/overview.html"
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