Baltic Sea

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Section 22/09/2006: Geostrophic Velocity with u velocity from ship adcp in 30m 40 cm s 1 10 35 Depth (m) 20 40 30 25 20 15 10 60 NORTH SOUTH 5 0 5 80 5 10 15 20 25 30 35 40 45 Section 29/09/2006: Geostrophic Velocity with u velocity from ship adcp in 30m 40 cm s 1 10 35 Depth (m) 20 40 30 25 20 15 10 60 NORTH SOUTH 5 0 5 80 5 10 15 20 25 30 35 40 45 Distance (km) Figure 4.9: Geostrophic velocities (m/s) of the two sections across the channel on the 22 September 2006 (upper panel) and on the 29 September 2006 (lower panel) between the reference level (30 m) and the bottom. more useful as investigated by Rubio et al. (2009), who compared dierent methods of estimating geostrophic velocities. Rubio et al. (2009) identied the option of ADCP data as a reference level as the preferred method when the investigated area is in a coastal region and therefore rather shallow. Although problems could arise when dealing with low quality ADCP data. Method 1 suggests high eastward velocities at the southern ank of the channel and high westward velocities in the middle of the channel, whereas the ADCP-method suggests high eastward velocities at the lower northern ank of the Stolpe Channel. The ADCP-method 58
captured eastward velocities up to 60 m on the northern ank in the water column, whereas at the repeat transect eastward velocities reached as high as 55 m on the southern ank coincides with the level of high eastward velocities measured by ADCP SFS on the southern ank of the channel (see upper left panel in Fig. 4.10). The calculation of geostrophic velocities explains only to some extent the velocities observed in the Stolpe Channel and are also just a snap shot. To investigate the amount of water transported through the Stolpe Channel over the three months deployment period other methods have to be applied. 4.3.3 Transports through the Stolpe Channel The two ADCPs at the outlet of the Stolpe Channel were deployed at 75 m depth along 17.5 ◦ E and measured currents in a 1 hour interval at either side of the channel. Their positions are marked in Fig. 1.1. ADCP SFN was deployed at the northern ank of the channel and ADCP SFS was deployed at the southern. Simultaneous data recordings of both ADCPs were conducted between 23 September 2006 and 19 December 2006 (87 days), covering a depth between 25 − 71 m. ADCP SFN (see Fig. 4.10 left panel) was a 600 kHz ADCP and therefore covered depths between 25 − 71 m, whereas the 300 kHz ADCP SFS covered the whole water column. Eastward ow of both ADCPs was mainly restricted to lower layers, between 65 − 71 m for SFN and between 52 − 71 m for SFS (compare Fig. 4.13). Westward ow predominated in the upper layers between 25 − 65 m for SFN and 25 − 52 m for SFS. Fig. 4.10 (upper right panel) gives the impression that eastward currents reached slightly higher up in the water column until highest eastward velocities were recorded in the beginning of November, but afterwards moved down again until the end of the recording period. On the northern side of the channel on three occasions (4 November 2006, 3 − 4 days after the 4 November and on 17 − 18 December 2006) a strong easterly ow was recorded throughout the whole water column which succeeded to break up the separation between the upper and lower layer. On the southern side of the channel (Fig. 4.10 upper right panel) the whole water column was dominated by an eastward ow on only two occasions, the 4 November 2006 and 3 − 4 days later. It was more often observed that westerly ow dominated the whole water column, especially after the big storm event at the beginning of November. Model simulations of the eastward currents of SFS indicate the good agreement between modelled and measured velocities (compare Fig. 4.11 with Fig. 4.10 upper right panel). The 59
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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
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Contents Abstract Contents List of
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Acknowledgement 109 Appendix 111 vi
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M-7/M-8 Mesodyn hydrographic snapsh
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List of Figures 1.1 Baltic Sea - ba
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4.32 Regression sea level dierence
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1. Introduction 1.1 Investigations
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circulation above topographic anks
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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 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: In the geostrophic balance horizont
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
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
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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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