APPENDIX B 



OCEANOGRAPHIC DATA 



1. INTRODUCTION 



The surface duct transmission experiments performed by the USS Rexburg and 

 the USNS Davis required persistent well defined surface layers. The areas 

 were selected after the thermal survey by the thermistor chain on the USS 

 Marysville . 



The first acoustic experiment was performed in the Boundary Region (Area I) 

 between the Eastern North Pacific Central Water and the Transition Water flow- 

 ing southward from the Arctic along the coast of California. The second acous- 

 tical experiment was performed in the Transition Water Region (Area II) to the 

 east of the Boundary Region. (See Figure 1 .) In the Boundary Region according 

 to Lee (Reference 1) the thermal profile generally shows some time dependence 

 whereas the Transition Water Region is more stable . 



Two sources of temperature data provided support for the acoustical experiments 

 carried out by the Rexburg and Davis . Both ships made bathythermograph casts 

 during the experiments at one- or two -hour intervals . In addition, the Marys- 

 ville took thermistor chain data in both the Boundary and Transition Water Re- 

 gions . The latter data were generally taken about a day before the acoustic ex- 

 periments, the shortest time differential being 10 hours in the Boundary Region. 

 Figures B-l and B-2 show the location of the tracks made by Marysville relative 

 to the acoustic runs . In the Boundary Region the Marysville 's course is close to 

 and parallel to the Rexburg-Davis acoustic experiment. In the Transition Water 

 Region the Marysville 's track was transverse to the line of the acoustic experi- 

 ment. 



2. THERMISTOR CHAIN DATA OBTAINED BY USS MARYSVILLE 



2 . 1 The Boundary Region . The operations of the Marysville and its therm- 

 istor chain data are described in detail in Reference (1) . 



For the first acoustic experiment the Marysville recommended to the Davis a 

 location at 29° 26.7' N, 126° 03.0' W where a dome in the temperature structure 

 occurred. Lee comments that such domes are generally time dependent. The 

 Marysville performed three traverses over this region, the last being some 10 

 hours before the arrival of the Davis . These thermistor chain surveys indicated 

 that the depth of the surface duct was about 200 feet and that this changed by less 

 than 40 feet in the course of the three runs (12 hours) . The runs indicated that 

 the thermal profile below the layer was space and time dependent . 



B-l 



Arthur ajUttlrJnr. 



