Investigation of Ice Dynamics in the Marginal Ice Zone.

• Main Authors: Leppaeranta,Matti, Hibler,William D. , III
• Other Authors: MARINE RESEARCH INST HELSINKI (FINLAND)
• Format: Text
• Language: English
• Published: 1987
• Subjects: Snow; Ice and Permafrost; *SEA ICE; *RHEOLOGY; CYCLES; DRIFT; DYNAMICS; FREQUENCY; ICE; INERTIAL SYSTEMS; KINEMATICS; LOW FREQUENCY; MEASUREMENT; MOTION; NOISE; PEAK VALUES; RATES; RED(COLOR); SHEAR PROPERTIES; STATIONS; VARIATIONS; VELOCITY; GREENLAND SEA; VISCOPLASTIC PROPERTIES; DEFORMATION; THICKNESS; PACK ICE; MATHEMATICAL MODELS; EDGES; SEA WATER; WATER WAVES; INTERFACES; OCEAN CURRENTS; FINLAND; Marinal zones; Ice mechanics; Ice water interface; Fram strait; ASH57; PE61102A; Greenland; Fram Strait; Greenland Sea; Ice; permafrost; Sea ice
• Online Access: http://www.dtic.mil/docs/citations/ADA181392; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA181392

The dynamics of sea ice in the marginal ice zone (MIZ) are considered both from theoretical and from experimental point of view. Ice kinematics measurements were made with the Del Norte microwave trisponder system in MIZEX-83 and MIZEX-84 Greenland Sea experiments. Differential ice motion was measured with four to six stations on the ice in the scale of 2-20 km at three minute intervals. On several occasions a rapid slip occurred in measured distances. Ice velocity fluctuations were typically of the order of 1 cm/s and large deformation rates a few per cent hour. Various spectra of differential ice drift showed a moderate inertial peak and a red noise character at higher frequencies, up to about half-hour period. The maximum rate of shear was about twice as large as divergence from 12-h to about 2-h period. Analysis of current measurements beneath the drifting ice show that current variations show up highly damped in the ice. In differential motion, ice-current coherence was significant only at low frequencies (lower than one cycle per day).