Pierson, Tick, and Baer 



of satellite data to improve on the initial specification of the conditions over the 

 ocean so as to obtain improved forecasts of the weather and wave conditions. 



A spacecraft in a near polar orbit can complete an orbit in about 90 min- 

 utes. Each orbit is about 22.5° away from the preceding orbit, and due to 

 "dwell" the higher latitudes are sampled more densely on an areal basis. Two 

 complete surveys of the ocean would be made each day. The six, or seven, suc- 

 cessive orbits that would provide the data for the North Pacific, say, would be 

 obtained in 10 hours. With a wind speed, or a wave height, every 90 nautical 

 miles along the subsatellite track, the result would be the equivalent of about 

 300 ships rather evenly spaced over the ocean and reporting on conditions. For 

 all oceans, in one day the satellite would be equivalent to about 2800 ship reports 

 spaced fairly uniformly over the oceans but concentrated at the higher latitudes. 



For a particular pass, one can think of the data as a series of values along 

 the line describing the subsatellite path. For the North Pacific again, as an ex- 

 ample, one pass would be completed in 20 minutes and would be essentially 

 synoptic. Were the satellite to pass over an extra tropical cyclone, the data 

 would provide either a wave section or wind speed section through the cyclone. 



The data can be compared with the winds and waves obtained from a con- 

 ventional wind field analysis and the wave computed from the above procedures. 

 A discrepancy would indicate a correction for the wind field to bring the results 

 into agreement, and the final result would be an improved surface wind field that 

 would yield improved meteorological and wave predictions. 



After the development of the procedures described for spectral calculations 

 and wind field calculations is completed, radar scatterometer data will be sim- 

 ulated and procedures for integrating it into improved wave forecasts and im- 

 proved wind fields will be developed. 



The final goal of this effort will be to use actual data from a spacecraft in 

 real time to generate wave forecasts and wind field forecasts based on wind 

 fields and initial wave conditions corrected by means of the spacecraft data. 



ACKNOWLEDGMENTS 



This research is being supported by two separate Task Orders with the 

 Naval Oceanographic Office under Contract N62306-1042. The purpose of one 

 Task Order as funded by Code RAAD-22, Airframe Design Branch of the Air 

 Systems Command, is to develop a wave hindcasting procedure for the North 

 Pacific and produce a wave climatology for one year of weather data. The pur- 

 pose of the second Task Order, monitored by the Spacecraft Oceanography 

 Project of Navoceano, is to extend the results to the entire globe and develop 

 ways to integrate data from a satellite into the problem of describing and pre- 

 dicting the surface winds and waves. 



We have been assisted in this work by Miss Catherine Vail, Mr. Louis 

 Adamo, Mr. Tokujiro Inoue, Miss Ming Shun Chang, Mr. Vincent Cardone, and 

 Mr. Hong Chin. The personnel of the Naval Oceanographic Office have been 



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