Investigation of structural properties of marine surface film manifestations on SAR images

D.V. Darkin, L. M. Mitnik, V. A. Dubina
V.I. Il‘ichev Pacific Oceanological Institute, Far Eastern Branch, Russian Academy of Sciences
43 Baltiyskaya St., 690041, Vladivostok, Russia
Phone: +7 (4232) 312-854 Fax: +7 (4232) 312-573
dvdarkin@poi.dvo.ru

ABSTRACT

Robust algorithms for detecting and classifying marine surface films on SAR imagery are a very important contribution to monitoring of environmental hazards (oil spills, harmful algae blooms) and physical oceanography (eddies, internal waves, currents etc.). Modern SAR sensors of Envisat and ERS-1/2 satellites provide high-resolution data that are available to POI through participation in ESA projects. Over 500 ERS-1/2 and Envisat precision images with spatial resolution of 25 and 150 m. were obtained as well as over 3000 so-called Quick Looks characterised by lower spatial and radiometric resolution. This dataset that covers the regions of Asian marginal seas (Okhotsk Sea, Japan Sea and China Seas) has allowed us to consider such descriptive features of manifestations of surface films on SAR images as the structure. SAR images originally represented as raster data were transformed into the vector form. Sets of elementary vectors were grouped into contours forming the structure of backscattering contrasts related to marine surface films on SAR images. Structural properties of natural as well as anthropogenic films were investigated in order to facilitate the creation of an automated algorithm for their identification and classification. During the analysis several case studies were selected for detailed investigation. Additional quasi-collocated data such as QuickSCAT-derived wind fields, NOAA AVHRR images and surface analysis maps was used in the analysis in order to assist in interpretation of the radar signatures. Based on investigations several quantitative structural measures are proposed for the description of active surface film signatures on SAR imagery. Conclusions and directions for further research are outlined.

Last Update: 2005-03-16