A preliminary assessment has been made of the capability of the Seasat synthetic aperture radar to detect ocean waves. Comparison with surface and aircraft measurements from five passes of the satellite over the Gulf of Alaska indicates agreement to within about - 15 percent in wavelength and about +/- 25 degrees in wave direction. These results apply to waves 100 to 250 meters in length propagating in a direction predominantly across the satellite track, in sea states with significant wave height (H((1/3))) in a range of 2 to 3.5 meters.
A new era of remote sensing for coastal and oceanographic monitoring was born on 26 June 1978 with the launch of Seasat. Duck-X was a 2 month experiment conducted during August to October 1978 off the east coast of the U.S.A. for the validation of the Seasat synthetic aperture radar (SAR). During this field experiment, various oceanographic phenomena were monitored. Ground truth observations of these phenomena have been correlated with Seasat SAR imagery. The ground truth sensors included airborne photographic and radar imagery, meteorological satellite imagery, land based radars, and conventional wave gauges. This paper focuses on oceansurfacewaves, oceancurrents and coastal inletdischarge.Specifically, the direction and length of the principal ocean wave trains are compared for the periods of Seasat overflight of the Duck-X area. During these overflights significant wave heights were I·5 m and less and the maximum wave period was 14 s. The current correlationsconcentrate on the westernboundary of the Gulf Stream and its associated eddy structure. Inlet outflow is shown for inlets on the east coast of the U.S.A.This ground truth study has indicated that the SAR imagery contains an unanticipated abundance of information on a variety of oceanographicand coastal phenomena.
A comparison has been made between ocean wave imagery acquired by the SeaSat-A SAR and surface truth collected during the NOAA-sponsored Gulf of Alaska SeaSat Experiment (GOASEX) performed i n September 1978.Five SAR passes were examined; two were near-shore and the remaining three were in the deep ocean. Four of these passes were coincident with two-dimensional power spectra measurements by a Pitch-Roll buoy; three of these overflew two NOAA d a t a buoys which provide onedimensional spectra; airborne X-and L-band SAR data was acquired coincident w i t h both near-shore passes and one deep ocean pass. Azimuth-traveling waves were not encountered i n this data set.The ranges of significant wave heights and wavelengths measured by surface truth were about 1 t o 3.5 meters and 100 to 300 meters, respectively.SeaSat (and airborne) SAR failed t o image the 1 meter swell , b u t d i d image 2.5 rn swell. Nithin these ranges, wave image quality appeared t o increase with both wavelength and significant wave height. Optical Fourier Transforms of the SeaSat SAR wave imagery were obtained, and these yielded agreement w i t h surface truth measurements of about -+lo% i n wavelength and ,20° in direction. 656
The U.S. Army Corps of Engineers water resources management programs have undergone changes during the past two decades, including a shift in emphasis from the construction of new projects to the operation and maintenance (O&M) of existing projects. Consequently, expenditures for new construction have fallen while the O&M of existing projects has claimed an increasing share of the total agency budget. Given the current outlook of declining fiscal resources, Corps managers have recognized a need to evaluate the way the organization is doing business. The Corps O&M program appropriated approximately $1.7 billion for fiscal year 1999 to support an inventory of more than 4,000 projects. The program is managed through 8 division and 38 district offices across the nation. The Operations and Maintenance Business Information Link (OMBIL) integrates national program performance measurement, starting with criteria gathered at the lowest level, the local water resource project. The overall impact on the O&M program is twofold: Frontline employees contribute directly to corporate performance measurement, ensuring a national effort to achieve corporate goals and objectives, and the management hierarchy is able to support users at all levels through this outcome-oriented process. The result is a modified business methodology that enables more efficient and effective decision making.
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