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This article was downloaded by: [University of Windsor]On: 13 November 2014, At: 03:07Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954 Registeredoffice: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
International Journal of RemoteSensingPublication details, including instructions for authors andsubscription information:http://www.tandfonline.com/loi/tres20
Dynamic features along the GermanBaltic Sea coast: contribution tocoastal monitoringH. Siegel Corresponding author a , M. Gerth a & T. Ohde aa Baltic Sea Research Institute Warnemünde , Seestraße 15,D-18119 Rostock, GermanyPublished online: 07 Jul 2010.
To cite this article: H. Siegel Corresponding author , M. Gerth & T. Ohde (2004) Dynamicfeatures along the German Baltic Sea coast: contribution to coastal monitoring , InternationalJournal of Remote Sensing, 25:7-8, 1403-1408, DOI: 10.1080/01431160310001592364
To link to this article: http://dx.doi.org/10.1080/01431160310001592364
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Dynamic features along the German Baltic Sea coast: contribution tocoastal monitoring
H. SIEGEL*, M. GERTH and T. OHDE
Baltic Sea Research Institute Warnemunde, Seestraße 15, D-18119 Rostock,Germany
Abstract. Based on satellite imagery in combination with ground data mea-surements and numerical modelling, the distribution patterns of water massesalong the German Baltic Sea coast of the state of Mecklenburg–Vorpommern(M–V) were investigated. The dynamic processes forming these patterns aredriven by the local wind. Distinct wind directions induce typical features inseveral regions of the M–V coast. The processes considered are the distributionof Oder river water in the Pomeranian Bight, the upwelling off Hiddensee andoff the coast of the Mecklenburg Bight including the Warnow river outflow, andthe special dynamic regime in Lubeck Bay. In the Pomeranian Bight, a strongrelation was found between the wind and transport direction of river waterwhich was also applied to interpret the distribution of inorganic and organicpollutants. During easterly winds, different upwelling cells arise with the highestintensity in the Hiddensee area. The cells merge by increasing wind velocity.Lubeck Bay is mainly excluded from water exchange during the dominant winddirections. The first results of this systematic remote sensing study along theentire coast of M–V are summarized and will be continued to support the coastalmonitoring programme of regional authorities.
1. Introduction
Satellite remote sensing is a powerful method for synoptic investigations of
highly variable distribution patterns of water masses. Satellite data of Sea Surface
Temperature (SST) allow one to study processes which result in temperature
differences, such as upwelling of cold water from deeper layers, coastal jets or river
water of lower density which is heated faster than the surrounding area. Ocean colour
data and derived water constituents permit investigation of plankton develop-
ment, distribution of river water enriched by water constituents or upwelling of
clear water. Therefore, SST and ocean colour data were used to study dynamic
processes (Siegel et al. 1994, Schmidt 1995) and the transport of river water in the
western Baltic Sea (Siegel et al. 1996, 1999).
On the basis of this knowledge the systematic studies of the Oder river dis-
charge were extended to the entire Baltic Sea coast of the German state
Mecklenburg–Vorpommern (M–V). The first results on the summarized dynamic
features are presented.
International Journal of Remote SensingISSN 0143-1161 print/ISSN 1366-5901 online # 2004 Taylor & Francis Ltd
http://www.tandf.co.uk/journalsDOI: 10.1080/01431160310001592364
An updated version of a paper originally presented at Oceans from Space ‘Venice 2000’Symposium, Venice, Italy, 9–13 October 2000.
*e-mail: [email protected]
INT. J. REMOTE SENSING, 10–20 APRIL, 2004,
VOL. 25, NO. 7–8, 1403–1408
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2. Area of investigation and database
Mecklenburg–Vorpommern is located at the southern coast of the western
Baltic Sea. The coast is characterized by inner lagoons, including the largest
freshwater discharge coming from the Oder river crossing the Szczecin Lagoon.
From a dynamic point of view the coastal area shown in figure 1 can be divided into
four main regions: (1) the Pomeranian Bight with the Szczecin Lagoon, Greifswald
Bay and west coast of Rugen Island; (2) the Hiddensee Island–Darss Peninsula
area; (3) Mecklenburg Bight; and (4) Lubeck Bay. The stations of the German
coastal monitoring programme of M–V are illustrated on the map.
The database includes satellite data from the sensors AVHRR (Advanced Very
High Resolution Radiometer) of the National Oceanic & Atmospheric Adminis-
tration (NOAA), SeaWiFS (Sea viewing Wide Field of view Sensor), WiFS (Wide
Field of view Sensor) of the Indian satellites IRS, Landsat TM (Thematic Mapper),
shipborne measurements and model simulations. This paper concentrates on SST
data provided by the German Federal Maritime and Hydrographic Agency
Hamburg (BSH). SST maps were derived from the infrared channels of AVHRR
(Siegel et al. 1994). Wind data are from the weather Station Arkona and from the
Oceanographic Data Acquisition Systems (ODAS) ‘Darss Sill’ and ‘Oder Bank’.
3. Results and discussion
Systematic studies of coastal processes started in the Pomeranian Bight to
identify the accumulation areas of the Oder river load using SST data (Siegel et al.
1994, 1996, 1999, Siegel and Gerth 2000). The applicability of SST was verified by
comparisons with in situ measurements during different wind conditions. Distinct
wind directions induce typical distribution patterns of the river plume as derived for
Figure 1. Map of the western Baltic Sea including the four areas under investigation(1, Pomeranian Bight; 2, Hiddensee–Darss Peninsula; 3, south-eastern MecklenburgBight; 4, Lubeck Bay), locations of wind registrations (A, Arkona; ODAS-DS, ODAS Darss Sill; ODAS-OB, ODAS Oder Bank), special locations(W, Warnemunde; D, Darss Peninsula; H, Hiddensee Island; GB, Greifswald Bay;U, Usedom Island; SL, Szczecin Lagoon) and the stations of the coastal monitoringprogramme.
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eight wind directions. The main wind directions were derived from a statistical
analysis of ten years of wind measurements (Siegel et al. 1996). In spring, with the
highest freshwater supply after the melting season, the highest frequency is from
easterly directions. In summer, autumn and winter, westerly winds are dominant,
moving to south-west in winter.
The investigation of the dynamical processes along the entire coast of M–V
included the patterns for the eight main wind directions as carried out for the
Pomeranian Bight. The SST distribution for the dominating easterly and westerly
winds is presented in figure 2.
Figure 2. Typical SST distribution patterns in the entire western Baltic Sea for dominatingeasterly and westerly winds.
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In the Pomeranian Bight (area 1) westerly winds transport the river load along
the Polish coast and the outflow of Greifswald Bay occurs eastwards into the
Pomeranian Bight. During easterly winds the Oder discharge is controlled by
upwelling processes at the Polish coast and transported along Usedom Island intothe Arkona Sea. During long easterly wind periods Greifswald Bay is filled up and
the sea-level increased, such that the Peene water is not transported into the bay but
flows northward and leaves it.
These investigations, results and experiences, in combination with satellite data
(SST and ocean colour) verified by shipborne measurements and numerical
circulation modelling (Siegel et al. 1999) were used to interpret patterns of inorganic
and organic pollutants, and also the nutrient composition during extreme con-
ditions related to the wind (Siegel et al. 1998).In the coastal area, between Hiddensee Island and the Darss Peninsula (area 2),
strong upwelling processes occur during north-easterly to south-easterly winds. The
upwelling filament is partly stopped by the Darss Sill. Temperature differences up
to 12‡K were determined. During intense upwelling phases the water of different
cells off Hiddensee and off the Mecklenburg Bight (area 3) south coast merge
together and leave the Baltic Sea (figure 2(a)). Particularly, in spring, cold and clear
water is transported to the surface, as is also visible in SeaWiFS-derived chlorophyll
maps showing low concentration in the upwelling water. During westerly winds, anonshore Ekman transport guides surface water towards the coast of areas (2) and
(3).
The dynamic processes in the Mecklenburg Bight include the discharge of the
Warnow river. The largest health resort in this area, Warnemunde, is located west
of Warnow river mouth which crosses the big town Rostock and a harbour. Due to
the east–west orientation of the coastline, the location of the beach and the
dominating wind directions, the beach is not directly influenced by the river. During
easterly winds, the water is transported westward in the direction of the beach but
cannot reach it due to the offshore Ekman transport and the established upwellingof cold and clear water.
Lubeck Bay (area 4) is subject to special hydrographic features. During the
dominating easterly and westerly winds, this area is mostly excluded from the
coastal–open sea water exchange that reflects the warm inner part of the bay in the
SST in figure 2. The large-scale circulation isolates this area (Schmidt et al. 1998).
During easterly winds, the cold upwelled waters of Hiddensee and Mecklenburg
Bight areas were transported with the surface outflow of the Baltic Sea without
entering Lubeck Bay. Therefore, considerable differences in the hydrographicconditions mostly occur between Mecklenburg Bight and Lubeck Bay.
In figure 3, a comparison between satellite-derived SST and continuous surface
temperature and salinity measurements in 2 m water depth are shown during a calm
situation just after easterly winds. In Lubeck Bay, the water temperature is higher
with hot spots in the inner part which may result from eddy development, as
described by Schmidt et al. (1998), on the basis of numerical modelling.
4. ConclusionsVariations in the distribution patterns of different water masses are very distinct
in river discharge areas, but they also occur in other coastal regions and can be
followed synoptically only by satellite data or simulated by circulation models. The
distribution patterns along the entire coast of M–V are highly variable and depend
strongly on the local wind-induced dynamic processes. The variations are in the
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temporal scales of the meteorological conditions (3–5 days) and monitoring
investigations need to take into consideration this variability. The results of these
remote sensing studies and planned systematizations of typical patterns during
dominating winds will support the interpretation of monitoring data and optimize
the coastal monitoring programme of regional authorities. Furthermore, they allow
one to forecast transport processes during special events, such as plankton blooms,
floods or accident.
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Berucksichtigung von Austauschvorgangen uber die Darßer Schwelle (Thesis, Rostock).SCHMIDT, M., SEIFERT, T., LASS, H. U., and FENNEL, W., 1998, Patterns of salt propagation
in the south-western Baltic Sea. Deutsche Hydrographische Zeitschrift, 50, 345–364.SIEGEL, H., and GERTH, M., 2000, Satellite-based studies of the Oder flood event in the
south-western Baltic Sea in summer 1997. Remote Sensing of Environment, 73,207–217.
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Figure 3. Surface temperature and salinity distribution measured from 24 to 26 September2000 in 2 m water depth and satellite-derived SST on 25 September 2000 of theLubeck Bay (area 4).
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