vvAVilS MP GUkF^mTS 



Construction of Refraction Diagrams 



The completed raanascript, "The Direct Construction of Wave Rays," 

 has been submitted to the Transactions, Merican Geophysical Union, and 

 the paper was presented at the tvashington, D. J., meeting of the Union on 

 May 5, 1952. An abstract foUovjs: 



In the construction 01 refraction diagrams for ocean waves the 

 rays (orthogonals) can be dravm more accurately if the approximate 

 formula A cc - (A t/Lsi/e) tan <^ > used by Johnson, O'Brien and 

 Isaacs (I9ii8) in the preparation of refraction protractors, is 

 replaced by ^ oT s5'//7 "'' [( | +AL/l) 5//7 OC ] -OC . In these 

 formulae OC is the angle between wave crest and depth contour 

 and L the wave Itugth taken at the oeginning of any contour 

 interval; /i OC axidAL are the corresponding changes over the 

 contour interval, A modified procedure for tiiu construction of 

 rays is presented. 



Very helpful discussions on the subject were held with Messrs, Saville 

 and Kaplan, of the Beach Erosion 3oard staff, and it was found that some 

 of the results reported were essentially the same as those which they had 

 achieved. 



Refraction of a Wave Pattern by Islands 



This investigation has been continued from the last quarter and 

 certain mathematical difficulties are now eliminated. The quantitative 

 effect of refraction by a circular island on a wave pattern possessing 

 both variability in direction of travel and wave length can be obtained 

 from the derived expressions. One or more numerical examples will be 

 worked out. 



IJear-Shore Temperature Fluctuations at Oceanside, California 



McEwen, Leipper, and others have recorded the daily temperature 

 fluctuations at the ocean bottom and surface at Scripps Pier and have 

 discussed the possible causes. Similar flucutations were found at the 

 Oceanside Pitr on 5 June and 20 June, when bathythermograph (BT) low- 

 erings were made throughout a time interval of U hours and 7, hours, 

 respectively. The preliminary results suggest that a Iff^^lel of colder 

 water with a component of motion toward shore displaces warmer water 

 from the lower levels. Thexi the cola wedge recedes away from shore and 

 is replaced by aarmer surf act water. The temperature at and near the bottom 

 in water 25 feet deep fluctuated through a range of 9°F. The presence of 

 these temperature changes at Oceanside, where the underwater topography 

 is relatively regular, suggests that irregularities on the scale of Scripps 

 and La Jolla Canyons are not an essential part of the mechanism. It is 

 hoped that sufficiently detailed measuT'emeats of temperature can be made to 

 permit an estimate of associated current velocities, 



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