Current studies in the Labrador current with respect to the motion of Icebergs

Russell, Wilson E.,(Wilson Eric) (1973) Current studies in the Labrador current with respect to the motion of Icebergs. Masters thesis, Memorial University of Newfoundland.

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Abstract

Currents were measured in an area of the Labrador current off the Coast of Newfoundland. The measurements were made at four stations over a period of three days. Three of the stations were along a two-mile line perpendicular to the expected mean flow. The fourth station was six miles upstream of the other three. Of the eight current measuring meters which operated successfully, three were at depths of approximately 15 m, two at 65 m and one each at 106 m and 218 m. -- The currents were found to be rotary in a clockwise direction. A comparison with theory showed that the near-surface currents were of an inertial nature; the measured periods of the near-surface currents being almost equal to the theoretical inertial period of 15.5 hrs. A curve was constructed showing the form of the correlation between the rotary currents at different depths at one of the stations. A vertical spiral effect similar to the Ekman spiral but rotating in time was interpreted from the shape of the curve. -- A study of measured iceberg tracks showed that the loops sometimes made by icebergs could quite possibly be caused by inertial current effects. One particular track which included several loops was examined in detail. The period and radius of the looping motion were found to be in the ranges of the inertial period and radius of influence. -- Geostrophic current profiles were constructed for a line near our research area. The oceanographic data used were obtained through the Canadian Oceanographic Data Centre and came originally from the International Ice Patrol. In the years 1961 to 1964 the oceanographic data were obtained using nansen casts while from 1965 onward the data were obtained using a Bisset-Berman, Salinity/Temperature/Depth (STD) Environmental Profiling System. All data were measured at approximately the same time of year. There were order-of-magnitude consistencies from profile to profile. It was hypothesized that a significant inertial current could result from a geostrophic current if the driving force behind the geostrophic current disappeared.

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