Arctic Oceanographic Measurements from Drifting Ice Islands. (1). Gravity Observations. (2).

• Main Authors: Hunkins,Kenneth L., Talwani,Manik
• Other Authors: LAMONT-DOHERTY GEOLOGICAL OBSERVATORY PALISADES N Y
• Format: Text
• Language: English
• Published: 1971
• Subjects: Geology; Geochemistry and Mineralogy; Snow; Ice and Permafrost; Acoustics; *MARINE GEOPHYSICS; *ARCTIC REGIONS; UNDERWATER SOUND; SOUND TRANSMISSION; ICEBREAKERS; SEA ICE; NAVIGATION; MARINE GEOLOGY; HYDROGRAPHIC SURVEYING; OCEANOGRAPHIC SHIPS; MAPS; Arctic; Arctic Ocean; Ice; permafrost; Sea ice
• Online Access: http://www.dtic.mil/docs/citations/AD0728803; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=AD0728803

Investigations in hydroacoustics and marine geophysics were conducted from two drifting ice stations, T-3 and Arlis II, in the Arctic Ocean. Long range sound propagation experiments were made over a number of paths between ice stations and also with icebreakers. The signals from explosives are transmitted to great ranges in the Arctic surface SOFAR channel. The character of these signals is explained in principal by both ray and mode theory. Background noise is created by cracking and crushing of the ice cover. The sources and variability of the background noise are discussed. Geophysical investigations included navigation, ocean depth, gravity and magnetics. Marine geological investigations included bottom photography, nephelometry and coring. Improvement of accuracy of sea gravity measurements by consideration of the cross coupling and off leveling errors is discussed. The use of satellite navigation for increasing navigational accuracy and hence the accuracy of gravity measurements is described. (Author)