The indirect dissipation method has been used to estimate momentum fluxes from a ship working in the outer marginal ice zone of the East Greenland Sea during the 1984 Marginal Ice Zone Experiment. These indirect measurements have been compared with direct eddy correlation measurements whenever the ship was moored to an ice floe and a sonic anemometer could be deployed. Neutral drag coefficients referenced to 10 m have been grouped in categories for various ice types and concentrations during 4- to 11-m/s winds. There is a gradual increase in the neutral drag coefficient with ice concentration and a doubling of the value in 70--90% concentration from 2.7¿0.3¿10-3 (mean plus or minus standard deviation) for a mixture of brash, small, and medium floes with rafted edges to 5.3¿0.5¿10-3 over very rough cakes and brash with many sharp vertical edges. Drag coefficients in this region of multiyear floes with larger roughness features are typically higher than most values obtained over ice and reported in the literature and up to 5 times larger than open ocean values for similar wind speeds. The drag coefficient is determined primarily by floe size, roughness, and concentration. ¿ American Geophysical Union 1987 |