Here we analyse high-resolution spaceborne synthetic aperture radar (SAR) measurements to retrieve statistical and dynamical properties of ocean eddies in the ice-free regions and the marginal ice zone (MIZ) of Fram Strait. Analysis of historical Envisat ASAR images allowes to obtain detailed spatial statistics of eddy generation sites, their diameters and vorticity sign. As shown, the total number of cyclones strongly dominates over anticyclones. Eddies are frequently observed over continental slope and shelf regions around Svalbard, however, about 80% of them are identified over the deep Fram Strait regions. In general, eddies range in size between 1.5 km and 64 km with a mean value of 8 km. Larger eddies of 10-30 km in diameter are usually found over deep water, while smaller eddies of 3-7 km in diameter prevail around Svalbard. As observed, the overall pattern of eddy field in the strait attributes well to the position of West Spitsbergen Current jet and its southern recirculation branch known from literature. Analysis of sequential Sentinel-1 images allows to retrieve surface current velocity field having a clear signature of an anticyclonic eddy in the Fram Strait marginal ice zone. Mean orbital velocity of the observed eddy is estimated to be around 0.4-0.5 m/s, in good agreement with earlier field observations. Presented results demonstrate the potential of spaceborne SAR data to retrieve critical properties of eddies of various scales, and further investigate their role in the Arctic Ocean.
In this work we present the results of internal solitary wave (ISW) observations derived from high-resolution spaceborne
synthetic aperture radar (SAR) measurements acquired over the seasonally ice-free Chukchi and Beaufort Seas. The
information on internal wave properties and locations was obtained from Envisat Advanced SAR (ASAR) images
acquired during May-October 2007 and 2011. Altogether, 233 ISW packets were identified in 727 ASAR images. As
observed, there is no significant difference in the normalized number of ISW observations between 2007 and 2011, while
most of the waves were detected in July (33%) and August (43%). Geographically, most of the waves were observed
over shelf and shelf break regions (94%), while only 6% of them were found over depths exceeding 200 m. In the
Chukchi Sea, the waves were frequently observed in the northern part of the sea centered at about 72.6° N, 168° W, in its
southwestern part, around Herald Shoal, near the Barrow Canyon, and in the Bering Strait. In the Beaufort Sea, some
ISW activity was observed along the shelf break and north of Cape Bathurst, while a major hot spot of ISW generation
was found on the Mackenzie Shelf. Maps of selected ISW properties, including their propagation direction, crest length
and wavelength of leading waves provide further details about spatial characteristics of the observed internal waves.
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