HR: 1340h
AN: SF53A-0732    [Abstracts]
TI: GPS Polarimeter for Sea State Sensing
AU: * Fleishman, M R
EM: mfleishman@stanford.edu
AF: Stanford University, Department of Geophysics, 397 Panama Mall, Stanford, CA 94305` United States
AB: Recent studies regarding sea surface wind estimation from spaceborne platforms have identified the Global Positioning System (GPS) constellation as a useful tool for measuring ocean wave topography. The twenty-four operational GPS satellites present a continuous, gratis radar source from which sea roughness can be derived accurately with unparalleled temporal resolution. However, existing GPS anemometers operate by recording the differing arrival times of direct (satellite--receiver) and reflected (satellite--sea surface--receiver) radar signals collected at a single elevated location. As this method is viable only at altitudes greater than 3 kilometers, such instruments are limited in real-time applications. A new variation on GPS wind sensing has been developed with the goal of acquiring real-time wind data at distances from a few meters to one kilometer from a water surface. Titled the GPS Polarimeter for Sea State Sensing (GPS3), this instrument operates by measuring changes in the GPS signal's polarization that occur instantaneously at the atmosphere-sea interface, thereby eliminating the requirement for a large receiver height. The GPS3's resulting portability, low cost, and simplified data recovery are well suited to a variety of recreational, scientific, and meteorological uses for which real-time local wind data is essential. Results of testing the GPS3 in controlled environments and on the open waters of the San Francisco Bay are presented in this poster. In all cases the GPS3 successfully received GPS signals reflected from water surfaces, and often the instrument's polarization-based measurement of the water roughness showed agreement with wind speeds determined by conventional means.
UR: http://pangea.stanford.edu/~mrf12/GPS3.pdf
DE: 3384 Waves and tides
DE: 4504 Air/sea interactions (0312)
DE: 4560 Surface waves and tides (1255)
DE: 4594 Instruments and techniques
DE: 0609 Antennas
SC: Special Focus: Advances in Data Acquisition, Management, Analysis and Display [SF]
MN: 2004 AGU Fall Meeting