Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 4

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  coastline changes
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
EN
The method introduced in this study for future projection of coastline changes hits the vital need of communicating the potential climate change impact on the coast in the 21th century. A quantitative method called the Dynamic Equilibrium Shore Model (DESM) has been developed to hindcast historical sediment mass budgets and to reconstruct a paleo Digital Elevation Model (DEM). The forward mode of the DESM model relies on paleo-scenarios reconstructed by the DESM model assuming stationary wind-wave climate. A linear relationship between the sea level, coastline changes and sediment budget is formulated and proven by the least square regression method. In addition to its forward prediction of coastline changes, this linear relationship can also estimate the sediment budget by using the information on the coastline and relative sea level changes. Wind climate change is examined based on regional climate model data. Our projections for the end of the 21st century suggest that the wind and wave climates in the southern Baltic Sea may not change compared to present conditions and that the investigated coastline along the Pomeranian Bay may retreat from 10 to 100 m depending on the location and on the sea level rise which was assumed to be in the range of 0.12 to 0.24 m.
EN
Changes of coastlines have economic and social impact on the human population concentrated in coastal areas. The investigation of coastal change processes becomes important particularly at sinking-retreating-coast for future planning, and the derivation of scenarios must be based on the understanding of the driving processes. It is well known that coastal change is a complex result of an interaction of climate driven eustatic sea level change and vertical crustal movements. An index is given that allows to distinguish between coasts controlled by glacio-isostatic processes and those determined by the climatic forces of coastal morphogenesis. A simple model allows reconstructions of the palaeo-geographic history of sinking coasts. Prognostic scenarios of coastal change are possible by applying of parameterized vertical crustal movement data and sea level change data derived from climate modeling. These data have to be superimposed with the influence of storm events. The coupling of processes on different time scales between hours and millennia are questions under investigation.
PL
Obserwowane w ostatnich latach na świecie sukcesywne nasilanie się procesów erozji brzegu (Zawadzka 1999, Pruszak 2003, Living with erosion... 2004) powoduje coraz szersze zainteresowanie naukowców, reprezentujących różne dziedziny nauki, problemami strefy brzegowej. Jednakże złożoność zachodzących na brzegu morskim procesów, ich przyczyn i uwarunkowań, stwarza poważne problemy w ich opisie. Wielokrotnie podejmowane próby wyjaśnienia mechanizmów reakcji zachodzących w strefie brzegowej, jak do tej pory, nie dały zadowalających wyników. Poznanie prawidłowości rozwoju linii brzegowej ma kluczowe znaczenie dla rozwoju regionalnego i zagospodarowania przestrzennego, szczególnie w aspekcie bezpieczeństwa brzegu i jego infrastruktury, a także planowania rozwiązań prawnych i finansowych w odniesieniu do obszarów zagrożonych zniszczeniem. Wykorzystanie w badaniach metod teledetekcyjnych może przyczynić się do wyznaczenia obszarów ulegających morfodynamicznym procesom erozji i akumulacji, a co za tym idzie do poznania prawidłowości rozwoju brzegu. Szczególnie do tego celu przydatne są przetworzone fotogrametrycznie zdjęcia lotnicze, które pozwalają na przeprowadzenie szczegółowych, krótko- i długookresowych obserwacji obejmujących swoim zasięgiem znaczny obszar. Celem prezentowanych badań było odtworzenie położenia linii podstawy wydmy / podnóża klifu wybrzeża Gminy Rewal w latach 1938, 1951, 1973 i 1996 oraz określenie na tej podstawie wielkości zmian i tendencji rozwojowych brzegu. W wyniku przeprowadzonych pomiarów określono wielkość i tempo zmian zachodzących w tym rejonie. Wykazano wyraźny charakter erozyjny analizowanego wybrzeża. Zaobserwowano znaczne zróżnicowanie wielkości zmian nawet na sąsiadujących ze sobą, jednorodnych geomorfologicznie, odcinkach brzegu. Wyznaczenie szczególnie zagrożonych odcinków brzegu, o znacznej wielkości i dynamice zmian erozyjnych, ma duże znaczenie zarówno dla samorządów lokalnych, jak i instytucji odpowiedzialnych za bezpieczeństwo brzegu, szczególnie w aspekcie obserwowanego nasilania się zjawiska erozji.
EN
In the last years, the intensity of erosion processes have been observed worldwide (Zawadzka 1999, Pruszak 2003, Living with erosion...2004). Consequently, coastal zone problems have become a focus of interest for researchers representing different scientific disciplines. The complexity of processes operating in the coastal zone, their causes, and effects are very difficult to describe and analyse. Previous efforts to explain interactions between the litho-, hydro-, and atmosphere were not successful. Using remote sensing data makes it possible to collect short- and long-time observation series on coastline changes, whereby coast development processes may be followed. Photogrammetric georeferenced aerial photographs, taken in different years, supply short and long-term observation series. The area of study was a 20 km long stretch of the western Polilsh coast in the Rewal municipality (Maritime Bureau km 380-360). Analyses were carried out based on 4 series of aerial photograph taken in 1938, 1951, 1973, and 1996. The 1996 series was used to develop an orthophotomap, which was subsequently used to calibrate the remaining series (1938, 1951, and 1973). The dune base /cliff foot line was identified on every picture in each year. The changes in the location was calculated in different time spans (1938-51, 1951-73, 1973-96). Results of the calculations were used to analyse trends in the coast development and the rate of the changes; classification of dynamics changes was effected as well. Based on coastline change diagrams for 1938-1951, 1951-1973 and 1973-96, the magnitude of coast accretion and erosion in the area were analysed. As indicated by the results obtained, the Rewal municipality coast is erosive. In all the periods analysed, a substantial diversity of the magnitude of changes was observed, even in neighbouring, morphologically homogenous areas. The temporal analysis indicates an increase in the length of the coast affected by erosion; at the same time, the accretion area has been reduced; the accumulative sections of the coast have become shorter and shorter. The situation recorded in aerial photographs represents a net effect of coastal processes, so measurements taken indirectly incorporate effects of every factor that produced changes in the dune base /cliff foot line position in an individual period, e.g., sea level changes, storm surge damages, impacts of coastal defence structure (link side effect), and other human activities. Application of aerial photographs to measurements of dune base line changes makes it possible to look for patterns in coastline development. Identification of dangerous sections of the coast, affected by heavy coastal erosion and high dynamics of changes is very important for spatial planning, coastal protection, and ther activities, particularly in the part of the coast exposed to erosion hazard.
EN
The knowledge about long- and short-term coastal changes plays a key role in Integrated Coastal Zone Management processes. This project was realized in the Laboratory of Remote Sensing and Marine Cartography of the University of Szczecin, within the framework of .Remote sensing research of the tendency the coastline changes of the Pomeranian Bay (3P04E05023). financed from the State Committee for Scientic Reseaerch (KBN) resources. The following data were used in this project: historical aerial photographs taken in 1938, 1951, 1973, 1996, topographic maps in the scale 1:10000, technical belt maps in the scale 1:2000 and DEM created for 2 km wide coastal belt. The area of research is 100 km long and is located at the Eastern part of Pomeranian Bay from Swinoujscie to Kolobrzeg. On the basis of the aerial photographs taken in 1996 with the use of DEM and OrthoMaster software an orthophotomap was created. The others aerial photographs taken in 1938, 1951 and 1973 were calibrated on the basis of this orthophotomap. Finally, all aerial photographs and maps were transfered into the same coordinate system PUWG1992/19. A dune base line / cliff food line and the geodetic monuments (kilometrage of the coast) were identified on every picture. Changes of dune base line / cliff food line location in time were measured. Results were presented for three selected areas of the coast located near Swina, Dziwna and Rega river mouths. The analysis of the coastal changes in the river mouth areas shows that this sections of the coast are very dynamic and have a big variability of the morphodynamic processes. This research can be useful in the protection of the coast, indicating relatively stable or dynamic places along the coast. The knowledge about such places is very important in the aspect of erosion hazard and safe planning in the Integrated Coastal Zone Management.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.