58 



THE NAVY OCEAN SCIENCE PROGRAM 



21" 



I — ■ — ] — ' — I — '—1 — ' — I — ' I ' r 



DEFLECTIONS OF THE VERTICAL. £, IN ARC-MINUTES 



-f-f-h-r-Hi-i-J-J-J- 



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"■ — I — ' — r 

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 I J.I.I-'- -l.l.l I 



I ASTRO-GEODETIC £ 

 • GRAVIMETRIC J 



UNDULATIONS OF THE GEOID, N, IN METERS 



oC 



10' 2r 50' 40' 30' 20' to- 20° 50' 40' 30' 20' (C 19° 50' 40' 30' 20' 



Deflections of the vertical (top graph) and undulations of the geoid (middle 

 graph) along a traverse across the Puerto Rico Trench, with compared values 

 based on astrogeodetic and gravity measurements. Profiles of gravity anomalies 

 and bottom topography are shown in the lower graph. 



Another important aspect of the instrumentation development 

 program is the effort to improve the navigation of research ships 

 at sea. One of the most Umiting factors in oceanographic re- 

 search is the reliabihty of ship positioning. Usually one mile is 

 the expected accuracy in the open sea when cloud cover permits 

 star fixes or where long-range electronic systems are available. 

 Earth satellites increase position accuracy by about an order 

 of magnitude, and in addition provide 24-hoiu"-per-day posi- 

 tioning. This increased accuracy will provide a new dimension 

 to ocean science at sea. The Navy Ocean Science Program is 

 providing this capability to oceanographic research ships en- 

 gaged in this program. 



It is patently obvious that oceanographers do not develop 

 electronic digital computers, but eflForts are now being made to 



