Sea‐ice and meteorological conditions in Northern Baffin Bay and the North Water polynya between 1979 and 1996

Abstract

In this paper we provide an overview of the meteorological and sea‐ice conditions within the northern portion of Baffin Bay and the region of the North Water (NOW) Polynya between Ellesmere Island and Greenland. Our results indicate an east‐west temperature gradient across the NOW and Baffin Bay regions with colder temperatures on the Ellesmere Island coast (‐14°C) and warmer temperatures on the Greenland coast (‐9°C). This is caused by warm air advection (upper level and boundary layer) due to prevailing atmospheric flows. The sea level pressure (SLP) pattern exhibits a pronounced inverted trough in Baffin Bay extending from a quasi‐stationary low south of Greenland. The trough deepens in winter thereby tightening the pressure gradient across the NOW region. This results in maximum winds (northerly) in winter. The trough also creates a mean cyclonic gyre in Baffin Bay, mirroring the spatial pattern of annual ice concentrations. The polynya is formed between November and March as a result of the annual appearance of an ice bridge in Smith Sound along with a northerly surface flow. The formation and duration of the ice bridge is shown to be highly variable and appears to be forming later and breaking earlier in the 1990s compared with the 1980s. The average sea‐ice formation and decay dates closely follow the mean temperature spatial pattern, illustrating a strong atmosphere‐surface coupling. Results show that the NOW region has several distinct sea‐ice anomaly patterns. These patterns consist of areas of high anomalous concentrations of sea ice which are consistent spatially and temporally. A ‘bridge dipole’ operates out of phase (e.g., as ice anomalies increase (decrease) in Nares Strait they decrease (increase) in Smith Sound). A ‘gyre dipole’ operates in phase between Smith Sound and the south‐west coast of Greenland. When concentration anomalies are negative (positive) in Smith Sound they are also negative (positive) along the south‐west coast of Greenland. We speculate that these links may be useful indicators of the response of the NOW region to climate variability and change.