Studies on water movements and sediments in Southern Lake Michigan : part 1[-3] ... / by John C. Ayers.

METHODS

The basic method of the study was the determination of current direction, current velocity, and water volume transport by
the dynamic height method of Ayers (1956) and Ayqrs and Bachman
(1957).
Bathythermograph lowerings at about twormile intervals (ca
2.5 miles on 10 August 1962) were made underway on courses parallel to the sill and, in all but one case, over the sill.
Navigation was by radar bearing and range out to about 20
miles from the shore being departed, by dead-reckoning in midlake, and again by radar from about 20 miles off the shore being
approached.
The first BT sounding was in each case from 1/2 mile to 2.5
miles from the shore being departed and the last at two miles,
more or less, from the shore being approached.
Vertical temperature profiles were read from the bathythermograph trace, in effect reducing the trace to a series of straightline segments of various lengths.
Corrected depth and temperature data were fed to an IBM 7090
computer which was programed to make all the necessary computations.
As a check, the section from Racine, Wisconsin, to Grand
Haven, Michigan, 9 November 1962 was calculated by hand. Agreement between hand calculation and computer calculation was
satisfactory.
Current direction (component normal to ship's course), and
velocity were obtained at each 10 decibar level from 0 to 60.

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