OCEANOGRAPHY 



1. Scientific work during the 1929 patrol season. 



2. Prediction of iceberg drifts. 



A. Surface isotherms as basis for prediction. 



B. Dynamic current maps as basis for prediction. 



3. Estimate of total annual amount of glacial ice south of forty-eighth parallel and its total chilling eftect 



on the water. 



4. Observations on iceberg disintegration south of the forty-fourth parallel. 



5. Possibility of breaking up icebergs artificially. 



6. Local convectional circulation about icebergs. 



7. Miscellaneous. 



1. SCIENTIFIC WORK DURING THE 1929 PATROL SEASON 



Following" immediately after this chapter the reader will find 

 figures showing a number of current diagrams and oceanographic 

 sections constructed from data obtained at some of the 69 oceano- 

 graphic stations occupied during the season. That portion of the 

 year's stations too isolated either in time or place to be utilized for 

 the construction of current diagrams or sections are of scientific 

 interest as records of 1929 surface and subsurface temperatures and 

 salinities in the vicinity of the Tail of the Grand Banks. There- 

 fore, all station data are given in full at the end of this pamphlet. 



Station procedure in general and the normal levels to be sampled 

 were the same in 1929 as since 1925. The main advantage in ad- 

 hering to the same levels year after year is that the values found 

 are then strictly and easily comparable over long periods of time. 

 Uncorrected Richter and Wiese reversing thermometers without 

 attached auxiliary thermometers were used in Greene-Bigelow 

 water bottles at all stations. The variable-speed electric hoists 

 used at the stations were ec(uipped with spooling devices that laid 

 up the ^^2-inch steel ^\•ire on the drums satisfactorily. The hoists 

 gave good service without any interruptions and there was no loss of 

 gear. 



One of the ice patrol's two electrical salinity determining cabinets 

 having worn out, the use of a titrating outfit for the Modoc was 

 obtained through the courtesy of Harvard University. This method 

 of determining salinities, new for the ice patrol, was purposely set 

 up and tried out during rough weather early in the season. It was 

 found perfectly workable when due precautions were taken to handle 

 the delicate glass instruments with care and to protect them by the 

 use of suitable racks and string ties. 



The electrical salinity measuring method as used on the ice-patrol 

 vessels is about twice as fast as the titration method and is much 

 easier and simpler; hence it should be used when a very large number 



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