Investigation of Small Scale Hydrodynamic Processes using High Resolution SAR Imagery and ADCP Data
Lavrova, Olga; Serebryany, Andrey
Space Research Institute of RAS, RUSSIAN FEDERATION

Results of experimental work obtained in September-October 2011 and June and September 2012 on the Black Sea shelf are presented. Sections from the shoreline to the shelf edge were conducted using acoustic Doppler profiler (ADCP) ''Rio Grande 600 kHz'' in conjunction with radar imaging of the region of experiment from satellites Envisat, RADARSAT-2 and TerraSAR-X and optical imaging by Envisat MERIS and Terra/Aqua MODIS. Also a mini probe measured temperature and sound speed vertical distributions and a chain of autonomous thermistors operated continuously at a shelf depth of 35m. Four experimental series allowed to measure current parameters in the northeastern coastal area of the Black Sea. Numerous anticyclonic and cyclonic small scale eddies were detected and their characteristics assessed, including current velocity and direction, eddy penetration depth, thermocline position in an eddy, etc. Comparison of ADCP data and high resolution satellite SAR data of TerraSAR-X and RADARSAT-2 showed that sea current shear zones were manifested as slick bands in SAR images. Cases of ADCP detection of short-period internal waves induced by the passage of an intense anticyclonic nearshore eddy are discussed. A heavy rainfall during the expedition was accompanied by turbid river outflows, therefore the eddy structures were best visible in ''suspended matter'' charts. Comparison of ADCP and satellite data showed that the area with southeastern current (countercurrent) was characterized by low concentration of suspended matter.

A unique series of SAR imaging from various satellites with high, 1-3m (RADARSAT-2 and TerraSAR-X), and medium, 75m (Envisat ASAR), resolutions was performed with the time span of several hours between the data acquisitions. This allowed to assess the usefulness and constraints of various radar products for different applications, investigation of current fine structure in particular. The work was conducted under projects of RFRBR #10-05-00428-a and the Russian Federal Thematic Programme ''Scientific and scientific-educational professionals of innovative Russia'' for 2009-2013. RADARSAT-2 and TerraSAR-X data were obtained under SOAR RADARSAT-2/TerraSAR-X Project #5074 project. ASAR Envisat data were provided by ESA under C1P.6342 and C1P.1027 projects.