Sea ice drifting and atmospheric processes over the central Arctic Ocean

Based on the data observed by drifting automatic weather station (DAWS) from August 2012 to February 2013 and NOAA re-analyzing data over the Arctic Centre,the track,movement velocity of drifting sea ice and the evolution of temperature,humidity,radiation of drifting sea ice,atmospheric processes,including the evolvement of flow pattern and temperature field and its relative dynamic and thermodynamic processes over the Arctic troposphere in 500 and 1000 hPa during period of autumn and winter around north polar are analyzed. The results show that,before 6 January 2013,sea ice moves mainly from the east to the northwest,and appearing the unstable trajectory of roundabout and turning process,then drifting towards to the south east. Its average drift velocity is 0.06 m/s,the maximum speed up to 0.4 m/s. The mutation and accelerated in the direction of polar sea ice drifting is associated with the activities of across the polar cyclone and jet stream in polar troposphere. Sea ice surface net radiation repeated short-term mutation process,resulting in the ice surface to absorb energy from the air,reduced the radiation cooling of sea ice in the Arctic area. In the autumn and winter it emerges sudden warming process in many time with the maximum increased of temperature reaches 30℃,caused conveying the warm and wet air flow. This kind of phenomenon is very rare in area of low and middle latitude. In the warming process it transports heat to the ice surface from the middle or up layer atmosphere may lead to ice floe rupture,fragile sea ice hardness,thickness of the slow growth of sea ice to accelerate the movement of the channel. This process may be one of the important mechanisms of the Arctic sea ice area and thickness reduction.