129 HAMON, B. V. 1962. "The Spectrums of Mean Sea-Level at Sydney, Coff s 

 Harbour, and Lord Howe Island," Journal of Geophysical Research . Vol 67, No. 

 13, pp 5147-5155. 



Daily mean sea-levels for the period July 1957 to December 1958 were 

 first adjusted to correspond to a fixed value of atmospheric pressure. The 

 spectrums and cross spectrums, coherences and phase differences of the ad- 

 justed sea-levels were computed for periods between 2 and 60 days. Spectrums 

 of atmospheric pressure were also computed. The atmospheric pressure spec- 

 trums contain peaks at periods of 9 and 5 days at all stations. The cross 

 spectrums between adjusted sea-levels at Sydney and Coff's Harbour show high 

 coherence at long periods; they also show that the Sydney series lags the 

 Coff's Harbour series by approximately one day. No explanation could be found 

 for this lag. The coherence between the Coff's Harbour and Lord Howe Island 

 series was low, especially at the longer periods. This is believed to be due 

 to movement of the axis of the east Australian current relative to the island. 

 (Author) . 



130 HANDS, E. B. 1976a. "Observations of Barred Coastal Profiles Under the 

 Influence of Rising Water Levels, Eastern Lake Michigan, 1967-71," CERC 

 Technical Report 76-1, US Army Corps of Engineers, Fort Belvoir, VA. 



Descriptions of lakeshore bathymetry and its temporal variations over a 

 4-year period are based on 125 shore-normal profiles from 35 stations and 

 aerial photos covering 50 km of shore near Pentwater Harbor on the eastern 

 shore of Lake Michigan. A sequence of four, well-developed, straight 

 longshore bars paralleled the shore. These bars were observed to merge with 

 one another only twice along the entire 50 kilometers, and were persistent 

 year-round features. There was also a temporary coastal bar which displayed 

 at least four distinct aerial patterns. 



In wavelength, lacustrine longshore bars overlap with the sand waves 

 from continental shelves; in relief, bars are somewhat smaller (0.1 to 2.2 m) . 

 Bar relief equals approximately one -half crest depth or one third trough 

 depth. The upper limit on the cross-sectional area of a given bar is 

 numerically about the same (in square m) as the spacing (in m) between it and 

 the next bar shoreward. As depth decreases toward shore, the cross-sectional 

 dimensions including bar height and spacing, decrease in regular progressions. 



Waves were observed to break almost exclusively by spilling, indicating 

 that contrary to previous reports, plunging- type breakers are not necessary 

 for bar development. The frequency of waves breaking on the outer bar was 

 calculated to be about 18 hours per decade, suggesting that the breakers at 

 this depth (averaging 5.3m) may occur too infrequently to account for 

 observed bar mobility and maintenance. 



From 1967 to 1971, the annual mean elevation of Lake Michigan rose 

 0.5 m. Inner bars north of Pentwater Harbor rose 0.5 m and migrated an 

 average of 26 m landward. The shoreline retreated, under the combined effects 

 of submergence and erosion, at a rate that averaged 4m per year. Landward 

 migration of longshore bars, exceeded shoreline retreat by 75 percent. This 

 difference may indicate a greater timelag in the response of the upper part of 

 the beach to rising lake levels. Continued monitoring of all profile stations 

 is desirable to determine whether the coupling observed between bars, 



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