A point at 20°N. latitude, 15i2i°W. longitude was selected as a standard reference 

 because the majority of the winds were easterly. Inspection of the charts indi- 

 cated that one value per day is sufficient to reflect the major changes in the 

 pressure pattern, so only the 1200Z charts were used. 



Table 3. — Cruise 1, computed surface winds and currents at 20 N. and 

 155°W. Winds were computed from 12002, U. S. Weather 

 Bureau Synoptic Charts by the method described in U. S. 

 Navy Hydrographic Office Miscellaneous Publication 11,275. 

 Currents were computed by Ekman's formulae 



The wind velocities were obtained by first computing the geostrophic wind 

 from the weather charts and then multiplying it by a reduction factor which took 

 into account the curvature of the isobars (H. 0. Misc. Pub. 11,275). Most of the 

 time the islands were under the influence of the Eastern North Pacific High, and, 

 as indicated by the large fetches, the isobars had little curvature, so 0.67, the 

 value for Isobars of small anti-cyclonic curvature, was used. During the periods 

 when lows or troughs were over the islands 0.60, the factor for isobars of great 

 cyclonic curvature, was used. Whenever possible, the reliability of these computed 



