Using of Landsat space images to study the dynamic of coastline changes in the Black Sea north-western part in 1983–2013

The problem of destruction of marine coastal zones, which are the most densely populated and developed areas in the world, is in focus of attention of many researchers globally whose efforts are concentrated on studies of natural and anthropogenic factors’ influence on intensity of shore erosion, which is caused first of all by changing of sea level and coastline abrasion, as well as revealing of critical coastline areas with maximal intensity of coast destruction processes. Besides, in line with the EU Marine Strategy Framework Directive, coastal abrasion has been chosen one of impact indicators for coastal ecosystems of European seas, having special importance for the Black Sea. The main impact of coastal abrasion on the marine environment is big volumes due to large amount of suspended matter entering coastal waters thus decreasing transparency and causing siltation, which dramatically damages coastal algal and seagrass communities and completely destroys natural processes of their reproduction. There are abrasion and cumulative types of coasts, which differ in prevailing processes and forming of different relief forms, which are characteristic of each type. The problem of coasts erosion is especially important for shallow north-western part of the Black Sea (NWBS), where intensity of coast destruction varies within broad limits for different parts of the coast and different periods of observation. According to the authors, coastal abrasion is the main mechanism of coastline formation in the NWBS. It has been shown that intensity of coastline forming processes is different for separate NWBS areas and depends on lithological composition of sea cliffs rock, sea level, wave’s direction and intensity, composition, direction and intensity of sediments flow, economic activities. Light and easily corrodible rocks dominate in the NWBS coasts. That is why more that 75% of sedimentary material is carried out from the coastal zone to the open sea driven by differentiation processes. It has been established that qualitative characteristics of beach drifting in the NWBS are characterized by high spatiotemporal variability from -1.5 to +5 m/ year. This is true for all the NWBS areas but the Danube River deltaic part, where beach drifting could reach +180 m/ year. At that it should be pointed out that instrumental studies have been brought down to a minimum in past decades due to economic reasons; the available sets of historical instrumental data are discontinued; observation points are located along the NWBS coast unevenly; local geological, hydrological, meteorological and economic conditions of the coast are very rarely taken into account. Therefore to study how the sea ecosystems are affected by intensity of shore (beach) drifting, currently remote sensing techniques (RST) are widely used. Using RST we are able not only assess coastal destruction, but also perform quantitative estimation of coastal areas increase/ decrease, quantify suspended terrigenous matter, nutrients and toxicants carried into the open sea and then accumulated in other coastal areas and/ or in bottom sediments. Aim of the work has been to study different coast areas’ growth/ reduction resulting from coastlines position dynamics changes under abrasion and accumulation processes in the North-Western Black Sea (NWBS) influenced by natural and anthropogenic factors over 1983-2013.
Ключові слова
Landsat space images, north-western Black Sea area, Destructions
Бібліографічний опис
In Geoinformatics: Theoretical and Applied Aspects 2020 (May 2020)