One of the most prominent polynyas in Northeast Greenland, already
noted by the early expeditions in the area, is located around Shannon
Ø and Pendulum Øer between 75° and 74°N in the transition
zone between the fast ice and pack ice. This study names the polynya
the ‘Sirius Water Polynya’, and examines its spatial and temporal
dynamics by analysis of recent satellite imagery, modelled meteorological
data and historical data covering the last decade. The
dominating mechanisms to form and sustain the polynya are inferred
and the persistence and inter-annual variability of the phenomenon
are estimated. The polynya formation is predominantly governed by
mechanical forcing caused by northerly gales, and it is classified
as a wind-driven shelf water polynya. A marked seasonal difference
in the surface wind field, together with the obvious seasonal cycle
in insolation, creates distinct winter and summer regimes in the
seasonal evolution of the polynya. During the winter regime, both
the size of and the ice cover within the polynya varies significantly
on a temporal and spatial scale. Intermittent wind-driven openings
of the polynya alternate with periods of increasing ice cover. Some
of the most persistent areas of open water in the polynya coincide
with locations where significant concentrations of spring and summer
settlements from the Thule Inuit culture (AD 1400-1850) are observed,
indicating a connection between the presence of the polynya
and the Thule Inuit living in the area in prehistoric times