The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder . easternberings00hood Year: 1981 Bering Sea ice-edge phenomena 207 submerged floes which were covered with small pieces of ice. Finally, Fig. 12-25 shows the appearance of the green floe at 23 hours. To summarize, during our observational period, the red floe moved from 58°'N, 170°'W to 58°'N, 170°'W, so that it travelled 32 km in the direction 210°, or at approximately 25° to the right of the average wind, at an average speed of m/sec, or at 4 percent of the mean wind
The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder . easternberings00hood Year: 1981 Bering Sea ice-edge phenomena 207 submerged floes which were covered with small pieces of ice. Finally, Fig. 12-25 shows the appearance of the green floe at 23 hours. To summarize, during our observational period, the red floe moved from 58°'N, 170°'W to 58°'N, 170°'W, so that it travelled 32 km in the direction 210°, or at approximately 25° to the right of the average wind, at an average speed of m/sec, or at 4 percent of the mean wind speed from Table 12-1. The two major forces acting on the band, which account for its relative motion, are aerodynamic wind drag on the rougher floes in the edge zone, and the force which results from absorption and reflection of wind waves and swell. Due to the shape and rough- ness factors, the thicker, rougher ice in the edge zone has higher drag coefficients than the thinner, smoother ice found inside the edge. For example, Banke et al. (1976) found through measurements that sharp-edged, rough pancakes have air-ice drag coef- ficients two to four times larger than smoother, thinner floes. From a force balance, this suggests that at the same wind speed the thicker, rougher ice will move slightly faster than the smooth ice. \o-ru ' NORTH WIND IRECTION SWELL DIRECTION Figure 12-22. A schematic diagram of the band of ice in which the targeted ice floes were found after 23 hours. The location of the floes is marked using the same notation as in Fig. 12-18. The dotted portion represents the edges of the band characterized by small fragments of ice, pancakes, and larger, mostly submerged floes. Thus, for wind speeds less than 5 m/sec, like those during the first few hours of the experiment, the thicker ice might move 1-2 cm/sec faster than the thinner ice. At wind speeds greater than 10 m/sec, this value may increase to a 10-20 cm/sec difference in speeds. These numbers c
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