The area of summer ice cover of the sea Weddel off the coast of West Antarctica has declined in comparison with 2013, a million square kilometers. The reason for the observed changes, as reported in Geophysical Research Letterscan be strong winds that brought warm air in 2016, and the occurrence of a large polynya.
Sea Weddel — unique region that contains the highest amount of perennial sea ice in the Antarctic, serving as a habitat for many species, including seabirds, seals and krill. Despite the fact that in the summer a large part of the ice cover in other regions of Antarctica melts, the main part of the sea Weddel remains frozen, as it is situated away from warm air masses that occur to the West of the Antarctic Peninsula and in other parts of the southern ocean. However, in the summer of 2016-2017 years the area of sea ice has fallen to record low values during the forty years of satellite observations.
John Turner (John Turner) from the British Council for the exploration of the environment, together with colleagues analysed satellite and atmospheric data on changes of ice cover of the sea Weddel, and robotic buoys collected information about changing ocean temperatures in the area. Ecologists have noticed that in December 2016 and January 2017, the ice area observed in the region in summer, decreased to 1.88 million square kilometers (while in the 2014-2015 year it was 3.33 million square kilometers), and this seasonal anomaly persisted over the next three years.
According to scientists, the reason for the observed reduction of the ice area can be a combination of several factors. In September 2016 the sea Weddel was observed West winds of record strength, which began to carry out multi-year sea ice from the region, and later, in December, was a powerful and deep the storm that brought warm air towards the Antarctic, melt a large part of the ice cover. In the result, in the winter of 2016 in the sea Weddel reappeared polynya area in tens of thousands of kilometers, which was first discovered in 1974-1976. As a result, the sun warmed ocean waters to abnormally high values — the average temperature in the summer amounted to 0.75 degrees Celsius, while the average climatological value was 0.32 degrees Celsius.