WP-3D Remote Sensors
Among the suite of airborne remote sensing instruments available on the WP-3D aircraft for the purpose of measuring surface winds in and around tropical cyclones are the Stepped Frequency Microwave Radiometer and the C-band scatterometer (C-SCAT). C-SCAT conically scans the ocean surfaceobtaining backscatter measurements from 20° to 50° off nadir
- C-Band Scatterometer (C-SCAT)
The C-SCAT antenna is a microstrip phased array whose main lobe can be pointed at 20°, 30°, 40°, and 50° off nadir, and the antenna is rotated in azimuth at 30 rpm. Thus, conical scans of the ocean surface are repeated every 2 s (0.25 km at 125 m/s ground speed).
Example: Time- azimuth representation of NRCS for a W-E pass (bottom-top) through the eye of Hurricane Tina on Sept 21, 1992 C-SCAT. High NRCS values are associated with capillary wave scattering in the upwind and downwind directions (upwind slightly higher than downwind). Low NRCS values are associated with cross-wind directions. Flight-level wind direction is superimposed and wind speed shown in the left panel. The eye is indicated by the dip in NRCS values at 1927 GMT, the white regions at 1923 and 1931 indicate the maximum wind locations. A secondary wind maximum and shift in surface wind direction is indicated at 1914 GMT.
- Black, P., R. McIntosh, C. Swift, J. Carswell, K. St. Germain, I. Popstefanija, and M. Goodberlet, 1995: Ocean surface wind, stress, and rain rate measurements in tropical cyclones from concurrent airborne microwave scatterometer and radiometer measurements. Reprints of the 27th Conference on Radar Meteorology, Vail, CO, AMS, 623-625.
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Updated August 28, 2001