Baltic Sea

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Stolpe Channel (or Stolpe Furrow, SF) connects the BB with the Gdansk Basin (GB) as well as with the Eastern Gotland Basin (EGB). The SF exhibits a maximum depth of about 93 m and forms a channel with an extension of nearly 80 km in the west-east direction. However, dense water spreading further eastward have to pass the Stolpe Sill with a peak level of about 60 m depth at its eastern gateway to reach the GB in the southeast as well as the EGB in the northeast. The central and largest deep basin of the Baltic Sea, the EGB, is closed from the elliptic 170 m isobath downwards and has a maximum depth of 249 m, Fig. 2.1, while the so-called Landsort Deep (LD) marks the deepest location of the Baltic Sea with a depth of about 490 m in the Western Gotland Basin (WGB). Turning back to the EGB and looking further to the northeast, the Gulf of Riga (GoR) is located in the east, while the Farø Deep (FD) continues the chainlike alignment of deep basins more in the north. Towards the northeast, the Gulf of Finland (GoF) constitutes the easternmost part of the Baltic Sea by an east-west extension. Finally, at higher latitudes, the Baltic Sea is closed by the Gulf of Bothnia which is separated from the central Baltic Sea (Baltic Proper) by the Åland Sea (ÅS). It constitutes of the Bothnian Sea (BS) in the south and the Bay of Bothnia (BoB) in the north. 1.3 Basic hydrography Due to restricted water exchanges with the North Sea and the location in the belt of the humid west-wind zone, the whole Baltic Sea is lled by brackish water of low salinity. Consequently, all saline inows from the North Sea produce/ maintaining a strong lateral surface gradient in salinity throughout all layers of the whole Baltic Sea. Relatively low values around 5 g/kg characterise the surface conditions in the Gulf of Bothnia while peak values of about 25 g/kg dominate corresponding conditions in the transition area of the Kattegat. Compared to the North Atlantic and the North Sea, the overall salinity in the Baltic Sea is much lower. Following Brogmus (1952) and HELCOM (1993), the overall Baltic water balance is positive with an annual freshwater surplus of about 481 km 3 . The associated riverine run-o amounts to 428 km 3 , the precipitation to 237 km 3 , and the evaporation to 184 km 3 . Consequently, the resulting annual Baltic outow of near-surface layers is compensated by an appropriate inow of nearly 500 km 3 saline and well oxygenated water from the Kattegat. The basic hydrography of all deep basins reects a permanent halocline separating the brackish 4
58 o N 190 230 210 100 75 100 100 75 75 30’ 57 o N 190 210 230 100 250 50 75 100 100 50 100 170 271 SW 170 230 150 170 190 NE SE 50 50 50 170 75 150 150 Latitude (deg) 30’ 210 230 190 100 75 50 100 75 100 50 56 o N 250 55 o N 170 30’ 222 30’ 75 100 190 230 210 250 150 150150 50 17 o E 75 75 50 SFN SFS 18 o E 75 50 75 100 19 o E 100 50 75 75 20 o E 12 o E 16 o E 20 o E 24 o E 28 o E 50 EGB 21 o E 66 o N 63 o N 60 o N 57 o N 54 o N Longitude (deg) Figure 1.1: Bathymetric map of research area (inserted Eastern Gotland Basin, EGB, blue Square) in the Baltic Sea. SFN and SFS are ADCP mooring positions within the Stolpe Channel (SF); Dots mark mooring positions SE, NE and SW within the EGB. Stars mark the positions of central HELCOMmonitoring stations 222 (SF) and 271 (EGB). Dotted blue lines indicate CTD transects across the Stolpe Channel and through the EGB. near-surface water from the dense, more saline deep water in near-bottom layers. For example, the halocline in the western AB is found between 35 m and 40 m depth. In contrast, it is located signicantly deeper within the EGB and occupies layers between 70 m and 90 m 5
Page 1 and 2: No 88 2012 Spatiotemporal Scales of
Page 3 and 4: Meereswissenschaftliche Berichte MA
Page 5 and 6: Abstract The Baltic Sea is surround
Page 7 and 8: Contents Abstract Contents List of
Page 9 and 10: Acknowledgement 109 Appendix 111 vi
Page 11 and 12: M-7/M-8 Mesodyn hydrographic snapsh
Page 13 and 14: List of Figures 1.1 Baltic Sea - ba
Page 15 and 16: 4.32 Regression sea level dierence
Page 17 and 18: 1. Introduction 1.1 Investigations
Page 19: circulation above topographic anks
Page 23 and 24: y 'new' deep water. For instance, i
Page 25 and 26: events. During and after such event
Page 27 and 28: this inow event was classied as 'mo
Page 29 and 30: Scale (PSS-78), roughly by 0.5%, as
Page 31 and 32: (Acoustic Doppler Current Proler) a
Page 33 and 34: for the southernmost zonal section
Page 35 and 36: whereas the length of the NE time s
Page 37 and 38: have a thickness of only 1.5 m in o
Page 39 and 40: dependent salt volumes for the deep
Page 41 and 42: 7 6.5 a Temperature ( o C) 6 5.5 5
Page 43 and 44: Potential Temperature ( o C) 8 7 6
Page 45 and 46: inowing waters masses with variable
Page 47 and 48: following these bounds will be used
Page 49 and 50: 60 80 100 −45 −50 −55 Pressur
Page 51 and 52: Monitoring Station BMP271 60 80 100
Page 53 and 54: Date 31.8.1997, 03.11.1997, 03.11.1
Page 55 and 56: 190 a 200 Depth (m) 210 220 230 240
Page 57 and 58: Date (ID) 〈S〉 V (g/kg) 〈θ〉
Page 59 and 60: deviation of the temperature uctuat
Page 61 and 62: 4. The Deep Circulation in the EGB
Page 63 and 64: Depth (m) 50 100 150 200 17 16 4.6
Page 65 and 66: For this reason, the displayed temp
Page 67 and 68: 6.4 6.3 178 m 208 m 223 m Daily Tem
Page 69 and 70: The deep parts of the basin are exp
Page 71 and 72:
On the 29 September 2006 between 60
Page 73 and 74:
In the geostrophic balance horizont
Page 75 and 76:
captured eastward velocities up to
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Figure 4.11: Modelled current veloc
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SFS and SFN. At the southern ank a
Page 81 and 82:
Mean Volume Transports Mean Volume
Page 83 and 84:
160 170 180 Volume of EGB below 170
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Basin 55.9 ◦ N. From there the bo
Page 87 and 88:
Volume transports (km 3 /d) 15 10 5
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Gdansk Basin happened a few weeks e
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needs some explanation, since the l
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and Fig. 4.24 and displayed in Tabl
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Salt (t) 8 6 4 2 0 2 4 6 8 x 10 10
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Time Period Stolpe Channel at 17.5
Page 99 and 100:
Modelled volume transport through S
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discovered that most of the varianc
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to the right (perpendicular) to the
Page 105 and 106:
of salty and often well oxygenated
Page 107 and 108:
Depth (m) 40 45 50 55 60 4 3 2 1 0
Page 109 and 110:
a correlation coecient of R=-0.68 a
Page 111 and 112:
5. Discussion and Conclusions 5.1 D
Page 113 and 114:
graphic cross-sections, conducted i
Page 115 and 116:
direction as the wind. The deep lay
Page 117 and 118:
Bibliography Axell, L. B., 1998: On
Page 119 and 120:
Griffies, S. M., R. C. Pacanowski,
Page 121 and 122:
Matthäus, W., 1993: Major inows of
Page 123 and 124:
Rubio, A., D. Gomis, G. Jordà and
Page 125 and 126:
Zhurbas, V., I. Oh and V. Paka, 200
Page 127 and 128:
Appendix Current speed and directio
Page 129 and 130:
Current speed and direction (cm/s)
Page 131 and 132:
2 1.5 1 Cumulative volume through S
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Volume (km 3 ) 2.5 2 1.5 1 0.5 0
Page 135 and 136:
10 3 Regional Wind 7 Power Spectra
Page 137 and 138:
NE along−slope at 178m 10 2 10 1
Page 139 and 140:
Meereswissenschaftliche Berichte MA
Page 141 and 142:
26 (1997) Lakaschus, Sönke: Konzen
Page 143 and 144:
51 (2002) Wasmund, Norbert; Pollehn
Page 145 and 146:
78 (2009) Wasmund, Norbert; Pollehn
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Baltic Sea

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