Variability of Sea Ice Extent Along The East Coast of Greenland

Abstract: There has been a decrease in sea ice extent and volume in the polar regions during the past decades; this study focuses on the Northern Hemisphere. The variability of the sea ice extent along the east coast of Greenland is examined and the area is divided into three regional zones to be able to study variations in the correlation strength along the coast. The ice extent along the east coast is achieved from highly accurate, manually produced ice charts from the Danish Meteorology Institute (DMI). The data of the ice extent along the east coast of Greenland is compared to SSM/I data of the ice extent of the entire Northern Hemisphere, achieved from passive microwave sensors for the years 2005-2012. The annual maximum and minimum sea ice extent of the different regions are compared. It was expected to see a negative correlation between the extent in the Northern Hemisphere and along the east coast of Greenland but the results showed a clear non correlation, with slightly higher R-squared values for the annual minimum period than for the maximum. The ice extent is mainly dominated by the ice drift, which in turn is controlled by the wind which follows the isobars of the surface pressure systems. It is therefore expected that the sea ice extent along the east coast of Greenland is highly correlated to the pressure difference across the Fram Strait. In this study a linear dependence between the sea ice extent along the east coast of Greenland and the pressure difference across the Fram Strait is sought for the years 2000-2012. The pressure difference is achieved using a new method; by taking the pressure difference between two weather stations on either side of the Fram Strait it is possible to get an approximate strength and direction of the wind in the middle of the strait, and thereby on the dominating force of direction of the ice. The results of the comparisons between the ice extent along the east coast of Greenland and the pressure difference show a correlation, especially for the annual minimum extent with R-squared values around 0,3. It is concluded that the variability of the sea ice extent is not solely predicted by the pressure difference, and that more parameters must be accounted for such as the surface air temperature.