ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

3aUW7. Ice activities during the AREA 88 experiment. I. A pictorial and video description.

T. C. Yang

Naval Res. Lab., Washington, DC 20375

During the AREA 88 experiment (Spring of 1988), an ice camp was deployed on an ice floe in the general neighborhood of 78 N and 55 W in the central Arctic. The ice floe became active on and off for a period of days. The ice activities were clearly audible in the air (a kind of low-frequency roar). One can unmistakably determine the direction of the noise by stepping outside the tent. Open and refrozen leads were found between the floes. One of them quickly closed up in a matter of minutes swallowing up the geophones just deployed on the refrozen lead. Immediately following this lead closing, the floe next to us started to move laterally at a speed approximately 3 ft/min. During a peak ice activity period, the ice at the edge of our ice floe started to pile up into a form called ice ridges, apparently due to forces between the ice floes which broke the ice and pushed them into a pile of irregular shapes. This ice ridging was recorded on a video tape. Tens to hundreds of blocks of ice of about 5- to 10-ft thickness were also found neatly lying on top of adjacent ice floes, a scene which looked like an act of God.