Analysis of Principal Components of the Sea Ice Concentration Fields in the Barents Sea

Abstract

The processes of interaction within the ocean-sea ice-atmosphere system which influence a multiyear ice cover dynamics in the Barents Sea are investigated. Being analyzed, the principal components of the sea ice concentration fields in the Barents Sea make it possible to distinguish three modes of interannual variability of the sea ice concentration. It is shown that the first mode describes 65.4 % of the sea ice concentration total variance and its multiyear trend. The second mode (10.8 %) is related to the variations of the heat inflow due to the sea currents governed by the atmospheric circulation. The third one (7.8 %) is associated with variability of the total turbulent heat flux from the ocean to the atmosphere at the boundary of the ice edge in the northern Barents Sea. Introduction. One of the most important regions for monitoring climatic changes in the Western Arctic is the Barents Sea [1, 2] which is attributed to the ice covered ones; but unlike the other Arctic seas, it is never completely covered by ice. Ice formation is usually observed in the north, east (off the archipelago Novaya Zemlya coast) and in the southeast of the sea. Depending on the hydrometeorological conditions, duration of the ice period is 6 -10 months [3]. Global increase of the air temperature observed during the past decades and especially pronounced in the Arctic region ("the effect of polar amplification") has already resulted in rapid reduction of the ice cover. At present, the ice area in the Barents Sea decreases much more rapidly (about 10.5 % during 10 years) than those in the other seas of the Arctic basin that demonstrates the worse negative trend in winter period [4 -6].Starting from the pilot paper [7], the basic factor conditioning climate of the Western Arctic seas including inter-annual variability of the ice cover area in the Barents Sea [8 -11] is considered to be heat advection by the North Atlantic Current. On the other hand, many authors emphasize the important role of the atmospheric factors, namely large-scale atmospheric circulation [12,13], cyclonic activity [14, 15], heat fluxes from the ocean to the atmosphere [16,17] and wind, in particular. For example, proceeding from the results of the 465-year numerical experiment, the authors of [18] concluded that the inter-annual variability of the ice area in the Barents Sea is conditioned mainly by the ice import or export occurring due to the local wind forcing; whereas heat transfer by currents is of noticeably less importance. It was also pointed out in [14, 19 and 20] that intensive north or south winds play an important role in displacement of the ice boundary in the Barents Sea.

Submesoscale Eddy Structures and Frontal Dynamics in the Barents Sea

“…For this reason this part is not considered when comparing eddy areas. In 2011 the eddies are recorded northward than in 2007, due to the larger ice-free water region [15]. But on the whole, the situation of the eddy structure clusters is similar in the both years (as well as the regions with the highest occurrence, except for the southeastern part of the sea), and the general regularities within the season throughout the data array (Tab.…”

“…To detect small (submesoscale) eddy structures in the Barents Sea 1203 and 838 satellite SAR-images of ENVISAT ASAR respectively in June -October 2007 and 2011 in the C-band and WSM (swath width is 400 kilometers, a spatial resolution -150 m) and IMP (100 km and 25 m, respectively) shooting modes. The choice of 2007 and 2011 years is due to the fact that in these years the minimum ice area in the sea area was observed [15]. On average, the coverage of the Barents Sea was 120 images SAR mages, while in 2011 its southeastern part was not practically covered by SAR images.…”

Seasonal Prediction of Arctic Summer Sea Ice Concentration from a Partial Least Squares Regression Model

“…It is apparent that, while the ice cover in the Arctic is retreating rapidly, the character of the changing ice is very different in the Atlantic and Pacific sectors [62][63][64][65]. A number of studies showed that the Barents Sea is one of the Arctic regions with the largest sea ice variability at different time scales [66][67][68] and the air-sea temperature differences in the Barents Sea are extremely large [69,70]. We can expect that sea ice change in the Barents Sea will greatly affect the heat release, thus affecting the local and possibly large-scale climatic conditions.…”