Remote Sensing of Ice Conditions in the Southeastern Baltic Sea and in the Curonian Lagoon and Validation of SAR-Based Ice Thickness Products

Abstract

Here we analyze ice conditions in the Southeastern Baltic (SEB) Sea and in the Curonian Lagoon (CL) using spaceborne synthetic aperture radar (SAR) data combined with in-situ measurements from coastal stations during four winter seasons between 2009–2013. As shown, the ice conditions in the SEB and in the CL are strongly varying from year to year and do not always correlate with each other. In the SEB, ice cover may form only within 5–15 km band along the coast or spread up to 100 km offshore covering almost the entire region. The mean ice season duration here is 45 days. The CL is almost fully ice-covered every year apart of its northern part subjected to sea water inflow and active shipping. The ice regime is also more stable here, however, it also possesses multiple periods of partial melting and re-freezing. In this study we also perform a validation of three SAR-based ice thickness products (Envisat ASAR 0.5-km and 1-km, and RADARSAT-2 0.5-km) produced by the Finnish Meteorological Institute versus in-situ measurements in the CL. As shown, all satellite products perform rather well for the periods of gradual ice thickness growth. When the ice thickness grows rapidly, all products underestimate the observed values by 10–20 cm (20–50%). The best results were obtained for the RADARSAT-2 ice thickness product with the highest R2 value (0.68) and the root mean square error around 8 cm. The results of the study clearly show that multi-mission SAR data are very useful for spatial and temporal analysis of the ice regime in coastal waters and semi-enclosed shallow water bodies where the number of field observations is insufficient or lacking.

Chronic Oil Pollution from Vessels and Its Role in Background Pollution in the Southeastern Baltic Sea

“…In winter, grease ice may take a shape similar to oil discharge from the moving vessel, or it may look like a huge oil spill (Figure 5). For the SEB, such ice phenomena are concentrated mainly in the coastal zone or near the canals connecting the SEB with the Curonian and Vistula Lagoons [63][64][65]. As an example, two slicks were reported as oil spills, and later it was proven that they were of natural origins (see Figure 5).…”

A Meta-Analysis of Sea Ice Monitoring Using Spaceborne Polarimetric SAR: Advances in the Last Decade

“…More MYI survives in the Arctic than in the Antarctic [8]. Sea ice monitoring consists of several applications, such as ice type classification [9]- [42], ice concentration [43]- [67] and ice thickness [68]- [79] estimation, and ice drift (or motion) retrieval [80]- [99]. Sea ice classification is considered one of the most important tasks for sea ice charting among these applications.…”