Baltic Sea

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m 2 /s. This estimate is a lower bound, since we may not have sampled exactly at the time of largest variance, and we cannot exclude that during the decay period some variance has been created during the late-stage of the inow event. The diusivity during the inow is therefore clearly enhanced with respect to values during stagnation periods, however, it is dicult to conclude if this is a result of double-diusive mixing or enhanced shear mixing associated with the motions of the intrusions. 44
4. The Deep Circulation in the EGB (Inter-basin communication of deep <strong>Baltic</strong> basins and their eects for the deep circulation) 4.1 Hydrography of the Eastern Gotland Basin During the RAGO eld campaign in September 2006 two diagonal cross-sections were conducted to monitor the current hydrographic situation of the EGB. The rst transect was conducted on the 26 September 2006 starting in the northeast corner of the basin travelling to the southwest corner. The transect contained 13 CTD proles measuring potential temperature, salinity, oxygen and pressure (see Fig. 4.1). The second transect conducted a day later covered the area from the northwest to the southeast corner (Fig. 4.2). The location of both transects is marked in Fig. 1.1. Both transects revealed a cold, oxygen- rich inow just below the halocline in 90 − 150 m with core temperatures of 5.6 ◦ C and an oxygen concentration of 1 ml/l. The inowing waters are easy to distinguish from the surrounding water, which contains somewhat higher temperatures (6 ◦ C) and is anoxic (0 ml/l). The inowing water masses slope from east to west across the basin. In the East they were located directly below the halocline in depths between 90 − 150m, whereas in the west they appeared in depths between 110-175 m. Since the two transects in September 2006 only provided a snapshot of the hydrographic situation in the EGB, further investigations were made to unravel the development of the timescale of the inow. A reliable source is the central monitoring station (BMP271, see Fig. 1.2) of the EGB, where depth proles of temperature, salinity and oxygen conducted in January/February, May, July, September and November 2006 revealed a high variability in temperatures and oxygen between 100 − 150 m depth (Fig. 4.3 A, B and E). Even in the rather stable salinity proles (Fig. 4.3 C) small uctuations were made out in those depths. Below 150 m temperatures clearly divide between warmer (January to July) and colder temperatures 45
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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 and 20: circulation above topographic anks
Page 21 and 22: 58 o N 190 230 210 100 75 100 100 7
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: deviation of the temperature uctuat
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
Page 77 and 78: Figure 4.11: Modelled current veloc
Page 79 and 80: 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
Page 85 and 86: Basin 55.9 ◦ N. From there the bo
Page 87 and 88: Volume transports (km 3 /d) 15 10 5
Page 89 and 90: Gdansk Basin happened a few weeks e
Page 91 and 92: needs some explanation, since the l
Page 93 and 94: and Fig. 4.24 and displayed in Tabl
Page 95 and 96: Salt (t) 8 6 4 2 0 2 4 6 8 x 10 10
Page 97 and 98: Time Period Stolpe Channel at 17.5
Page 99 and 100: Modelled volume transport through S
Page 101 and 102: discovered that most of the varianc
Page 103 and 104: 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
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5. Discussion and Conclusions 5.1 D
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graphic cross-sections, conducted i
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direction as the wind. The deep lay
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Bibliography Axell, L. B., 1998: On
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Griffies, S. M., R. C. Pacanowski,
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Matthäus, W., 1993: Major inows of
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Rubio, A., D. Gomis, G. Jordà and
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Zhurbas, V., I. Oh and V. Paka, 200
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Appendix Current speed and directio
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Current speed and direction (cm/s)
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2 1.5 1 Cumulative volume through S
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Volume (km 3 ) 2.5 2 1.5 1 0.5 0
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10 3 Regional Wind 7 Power Spectra
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NE along−slope at 178m 10 2 10 1
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Meereswissenschaftliche Berichte MA
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26 (1997) Lakaschus, Sönke: Konzen
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51 (2002) Wasmund, Norbert; Pollehn
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78 (2009) Wasmund, Norbert; Pollehn
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