Upper Ocean Internal Waves in the Marginal Ice Zone of the Northeastern Greenland Sea

• Main Authors: Eckert, Eric G., Foster, Theodore D.
• Other Authors: CALIFORNIA UNIV SANTA CRUZ
• Format: Text
• Language: English
• Published: 1990
• Subjects: Physical and Dynamic Oceanography; Snow; Ice and Permafrost; *PACK ICE; *OCEAN WAVES; *INTERNAL WAVES; MEASUREMENT; TEMPERATURE; HIGH FREQUENCY; OCEAN CURRENTS; SHAPE; TIME SERIES ANALYSIS; MOTION; TOPOGRAPHY; ELECTRICAL CONDUCTIVITY; PHASE; SPECTRA; ICE; WAVE PROPAGATION; VERTICAL ORIENTATION; MEASURING INSTRUMENTS; SEPARATION; HORIZONTAL ORIENTATION; ENERGY LEVELS; BOTTOM; FLOWMETERS; ARCTIC REGIONS; GREENLAND SEA; WAVE PACKETS; OCEANOGRAPHY; DISPERSION RELATIONS; ARCTIC OCEAN; STRAITS; DENSITY; UNDERICE; FREQUENCY; REPRINTS; FRAM STRAIT; MARGINAL ICE ZONES; Arctic; Arctic Ocean; Greenland; Munk; Fram Strait; Greenland Sea; Ice; permafrost
• Online Access: http://www.dtic.mil/docs/citations/ADA225173; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA225173

Oceanographic measurements obtained in the northeastern Greenland Sea-Fram Strait region were studied to characterize internal wave activity in the MIZ of the Arctic Ocean. Experiment were performed with an array of horizontally separated currents meters and a CTD instrument in 1984. Spectra of horizontal and vertical motion show that within the frequency range from the inertial frequency to 3 cph the MIZ internal wave field is similar in spectral shape and energy content to the wave field found beneath Arctic pack ice. Above 3 cph the MIZ spectra contain more energy than expected based upon both beneath- ice measurements and the Garrett-Munk model spectra. Elevated energy levels at high frequencies are shown to be caused by intermittent increases in internal wave activity occurring on time scales of 2-12 hrs. Phase differences between pairs of time series, computed during the passage of several packets of internal waves, are used to estimate horizontal wave number vectors. Comparison of the calculated wave number vectors to a dispersion relation derived from a simple normal mode model of internal waves suggests that the wave packets may be adequately described as being comprised of lowest-mode, horizontally propagating internal waves. Interaction of ice bottom topography with a sharp, elevated pycnocline is explored as a possible source of the intermittent increases in wave activity. (EDC)