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Oceanic dynamic phenomena and sea ice in the Southern Okhotsk Sea: study with ALOS PALSAR and ancillary data

Leonid Mitnik(1)

(1) Pacific Oceanological Institute, FEB RAS, 43 Baltiyskaya Street, 690041 Vladivostok, Russian Federation

Abstract

The Southern Okhotsk Sea is characterized by significant seasonal variations of oceanic and atmospheric parameters. Intended coastal line, straits connecting the Okhotsk Sea with the Japan Sea and the Pacific Ocean, cyclone’s passing and river's discharge are responsible for complicated water dynamics. Interaction of strong tidal flows with islands and bathymetric features also generates fronts, eddies and internal waves. Sharp thermal and ocean color contrasts are usually associated with the warm and cold currents and the wind induced upwellings. Satellite SAR is a valuable tool providing all-weather data on the mesoscale and fine-scale features of oceanic phenomena and processes. The main dynamic features of the studied area are the Soya Warm Current (SWC), which transfers the warm and saline Japan Sea waters through La Perouse Strait into the Okhotsk Sea and the East Sakhalin Current carrying drifting ice and cold fresh waters southward along eastern Sakhalin coast. The SWC front as a narrow light straight or wavy line and a cold belt just off the current having the darker tone were reliably delineated on many PALSAR images. The front can be traced during all seasons, however, in summer and autumn the transport and velocity of the current as well as its radar and thermal contrasts against the cold belt reach maximum. A rather remarkable assemblage of oceanic dynamic phenomena such as currents, coastal fronts, eddies, internal waves, as well as sea ice were evident in the PALSAR images of Sakhalin shelf and the area between southern Sakhalin and Hokkaido. PALSAR images were analyzed together with Terra and Aqua MODIS images, ocean color data, Aqua AMSR-E brightness temperatures, QuikSCAT-derived wind fields, surface analysis maps, bathymetry maps, etc. and compared with C-band ERS-1/2 and Envisat SAR images.

 

Symposium presentation

 

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