Observed features of sea ice motion with the ice buoy in the central Arctic Ocean and Fram Strait
HAN Hongwei1, LEI Ruibo2*, LU Peng3, LI Zhijun3
1 School of Water Conservancy and Civil Engineering, Northeast Agricultural University, Harbin 150030, China;
2 Key Laboratory for Polar Science of the State Oceanic Administration, Polar Research Institute of China, Shanghai 200136, China;
2 Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116024, China
Using six ice-tethered buoys deployed in 2012, we analyze the sea ice motion in the central Arctic Ocean and Fram Strait. The two-hourly magnitude of buoy-derived ice velocity within a band of 0.01 to 0.80 m·s-1, and the ice velocities in the Arctic Basin were generally less than 0.4 m·s-1. Based on the complex Fourier transformation, the amplitudes of sea ice velocities show a non-symmetric inertial oscillation and the inertial oscillations are evidenced by a strong peak at the frequency of about −2 cycle·d-1 on the velocity Fourier spectrum. The wind as a main driving force for the ice motion, the result showing there was a linear relationship between the observed ice velocity and 10-m wind speed, it turns out that the ice velocity was typically about 1.4% of the 10-m wind speed. According to the statistical analysis on the observed ice velocity and skin temperature, the ice velocity is growing by nearly 2% with a 10 °C increase in skin temperature, which is likely due to the weakened ice strength with an increasing temperature. The ice-wind turning angle also has a connection with the wind speed and skin temperature. When the wind speed is less than 12 m·s-1 or the skin temperature is less than −30°C, the ice-wind turning angle is decreasing with the increasing of wind speed or skin temperature.
Arctic sea ice; velocity; inertial oscillation; wind; skin temperature