Summary of the Northeast Water Polynya formation and development (Greenland sea)

The mechanisms forming the Northeast Water Polynya (NEWP), located on the shelf northeast of Greenland, are elaborated for different sub-domains of the polynya for the years 1990–1993. Sea-ice formation, sea-ice melt and the horizontal divergence of ice-floe velocity owing to winds and currents are investigated for the sub-domains. Several shelf-ice barriers of different size extend perpendicular to prevailing currents and winds causing a divergence of the ice-field flow in their lee. In summer, winds are weak and the northwand flowing coastal current in combination with Norske Øer Shelf Ice (NØSI) constitutes the dominant forcing of the Northeast Water summer polynya forming in the southern part of the NEW area. During this season the polynya gradually increases its size towards the north since the air-sea heat budget is positive then and now ice-formation takes place. In winter, strong northerly wind outbreaks push newly formed sea-ice out of Ob Bank region in the northern NEW area which is sheltered by Ob Bank Shelf Ice (OBSI) and the eastern coast of Kronprins Christians Land. Since during the winter season the air-sea temperature difference can amount to up to 30°C new ice forms rapidly balancing the ice export.