On spreading of Antarctic Bottom Water in fracture zones of the Mid-Atlantic Ridge at 7–8°N
Abstract and keywords
Abstract (English):
A Data-Interpolating Variational Analysis in n-dimensions was used to describe a potential temperature distribution in the bottom layer of the fracture zones of the Mid-Atlantic Ridge at 7–8°N. This analysis was based on a new digital terrain model obtained by supplementing the STRM15+ bathymetry data with multibeam echo sounding data from the 33rd cruise of the research vessel Akademik Nikolaj Strakhov (2016) and oceanological data from the World Ocean Database, supplemented with CTD profiles and reversing thermometer data measured in scientific cruises of the Shirshov Institute of Oceanology, Russian Academy of Sciences in 2014–2016. A 2D model of near-bottom potential temperature distribution in the study area was calculated based on the analysis. The model allows us to propose the Antarctic Bottom Water propagation pattern through the Doldrums, Vernadsky, and Pushcharovsky fracture zones. It is shown that bottom water warms up when passing fracture zones from 1.4°C in Pushcharovsky Fracture Zone up to 1.6–1.7°C in Vernadsky Fracture Zone. Bottom water from Pushcharovsky and Vernadsky fractures propagates in two directions. Northernly, it propagates to the Doldrums Fracture Zone, where its temperature reaches about 1.9–2.0°C. Easterly, it flows along Pushcharovsky Fracture Zone and raising the temperature up to 1.8–2.0°C. We propose the absence of Antarctic Bottom Water's overflow with a temperature less than 1.8°C to the East Atlantic in the study area.

Keywords:
Antarctic Bottom Water, Mid-Atlantic Ridge, fracture zones, bottom topography, multibeam echo sounding, potential temperature
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References

1. Barth, A., C. Troupin, et al. (2021), Variational interpolation of high-frequency radar sur-face currents using DIVAnd. Ocean Dynamics, 71, No. 3, 293-308.

2. Barth, A., J. M. Beckers, et al. (2014), divand-1.0: n-dimensional variational data analysis for ocean observations. Geoscientific Model Development, 7, No. 1, 225-241.

3. Beckers, J. M., A. Barth, et al. (2014), Approximate and efficient methods to assess error fields in spatial gridding with data interpolating variational analysis (DIVA). Journal of Atmospheric and Oceanic Technology, 31, No. 2, 515-530.

4. Belgacem, M., K. Schroeder, et al. (2021), Climatological distribution of dissolved inorgan-ic nutrients in the Western Mediterranean Sea (1981-2017). Earth System Science Data Discussions, 1-49.

5. Boyer, T.P., O. K. Baranova, et al. (2018), World Ocean Database 2018.

6. Dai, J., H. Wang, et al. (2020), Observed spatiotemporal variation of three-dimensional structure and heat/salt transport of anticyclonic mesoscale eddy in Northwest Pacific. Jour-nal of Oceanology and Limnology, 1-22.

7. Demidov A. N., S. A. Dobrolyubov, E. G. Morozov, R. Yu. Tarakanov (2007), Transport of bottom waters through the Vema Fracture Zone in the Mid-Atlantic Ridge, Doklady Earth Sciences, 416, No. 7, pp. 1120-1124.

8. Demidov, A. N., A. A. Ivanov et al. (2020), Transport of deep and bottom waters through the Mid-Atlantic Ridge in the Vema fracture zone. Doklady Earth Sciences, 494, No. 1, 735-740.

9. Demidov, A. N., E. G. Morozov, R. Y. Tarakanov (2011), Structure and transport of bot-tom waters through the chain fracture zone of the Mid-Atlantic Ridge. Russian Meteorolo-gy and Hydrology, 36, No. 8, 542-548.

10. Frey, D.I., E.G. Morozov et al. (2019), Regional modeling of Antarctic Bottom Water flows in the key passages of the Atlantic. Journal of Geophysical Research: Oceans. V. 124. № 11. P. 8414.

11. Friedrichs, M. A., M. M. Hall (1993), Deep circulation in the tropical North Atlan-tic. Journal of Marine Research, 51, No. 4, 697-736.

12. Friedrichs, M. A., M. S. McCartney, M. M. Hall (1994), Hemispheric asymmetry of deep water transport modes in the western Atlantic. Journal of Geophysical Research: Oceans, 99, No. C12, 25165-25179.

13. GDAL/OGR contributors (2021), GDAL/OGR Geospatial Data Abstraction Software Li-brary. Open Source Geospatial Foundation. URL https://gdal.org

14. GEBCO Bathymetric Compilation Group 2020 (2020), The GEBCO_2020 Grid - a con-tinuous terrain model of the global oceans and land. British Oceanographic Data Centre, National Oceanography Centre, NERC, UK. doi:10/dtg3.

15. Harris, C. R., K. J. Millman, et al. (2020), Array programming with NumPy. Nature, 585, No. 7825, 357-362.

16. IHO Standards for Hydrographic Surveys, Edition 6.0.0, (2020), URL: https://iho.int/en/standards-and-specifications (July, 2021).

17. Johnson, G. C. (2008), Quantifying Antarctic bottom water and North Atlantic deep water volumes. Journal of Geophysical Research: Oceans, 113, No. C5.

18. Korablev, A., O. K. Baranova, et al. (2014), Climatological atlas of the Nordic Seas and northern North Atlantic, NOAA Atlas NESDIS, 77, 122 p.

19. Locarnini, R. A., T. Whitworth, W. D. Nowlin (1993), The importance of the Scotia Sea on the outflow of Weddell Sea Deep Water. Journal of Marine Research, 51, No. 1, 135-153.

20. McCartney, M. S., S. L. Bennett, M. E. Woodgate-Jones (1991), Eastward flow through the Mid-Atlantic Ridge at 11 N and its influence on the abyss of the eastern basin. Journal of Physical Oceanography, 21, No. 8, 1089-1121.

21. McDougall, T. J., P. M. Barker (2011), Getting started with TEOS-10 and the Gibbs Sea-water (GSW) oceanographic toolbox. SCOR/IAPSO WG, 127, 1-28.

22. Mercier, H., K. G. Speer (1998), Transport of bottom water in the Romanche Fracture Zone and the Chain Fracture Zone. Journal of Physical Oceanography, 28, No. 5, 779-790.

23. Mercier, H., P. Morin (1997), Hydrography of the Romanche and Chain fracture zones. Journal of Geophysical Research: Oceans, 102, No. C5, 10373-10389.

24. Molinari, R. L., R. A. Fine, E. Johns (1992), The deep western boundary current in the tropical North Atlantic Ocean. Deep Sea Research Part A. Oceanographic Research Pa-pers, 39, No. 11-12, 1967-1984.

25. Morozov, E. G. (1995), Semidiurnal internal wave global field. Deep Sea Research Part I: Oceanographic Research Papers, 42, No. 1, 135-148.

26. Morozov E.G., A. N. Demidov, R. Yu. Tarakanov (2008). Transport of Antarctic waters in the deep channels of the Atlantic Ocean. Doklady Earth Sciences, 423, No. 1, p. 1286. Springer Nature BV.

27. Morozov, E. G., A. N. Demidov, et al. (2010), Abyssal channels in the Atlantic Ocean: Water structure and flows. Springer Science & Business Media.

28. Morozov E. G., R. Yu. Tarakanov (2014), The Flow of Antarctic Bottom Water from the Vema Channel to the Brazil Basin. Doklady Earth Sciences, 456, No. 2, p. 227-230.

29. Morozov E. G., R. Yu. Tarakanov, D. I. Frey (2021), Bottom Gravity Currents and Over-flows in Deep Channels of the Atlantic Ocean. Observations, Analysis, and Modeling. Springer International Publishing, 483 p.

30. Morozov E.G., R. Yu. Tarakanov, H. van Haren (2013), Transport of AABW through the Kane Gap, tropical NE Atlantic Ocean, Ocean Science, 9, pp. 825-835. doihttps://doi.org/10.5194/os-9-825-2013

31. Morozov, E. G., R. Y. Tarakanov, N. I. Makarenko (2015). Flows of Antarctic bottom wa-ter through fractures in the southern part of the North Mid-Atlantic Ridge. Oceanology, 55, No. 6, 796-800.

32. Morozov, E. G., R. Y. Tarakanov, et al. (2012), Abyssal cataracts in the Romanche and Chain fracture zones. Doklady Earth Sciences, 446, No. 2, 1211. Springer Nature BV.

33. Morozov, E. G., R. Y. Tarakanov, et al. (2017), Flows of bottom water in fractures of the North Mid-Atlantic Ridge. Doklady Earth Sciences, 474, No. 2, 653-656. Pleiades Pub-lishing.

34. Morozov, E. G., R. Y. Tarakanov, et al. (2018), Bottom water flows in the tropical frac-tures of the Northern Mid-Atlantic Ridge. Journal of Oceanography, 74, No. 2, 147-167.

35. Pushcharovsky Yu. M., Yu. N. Raznitsin (1991), Structure of the Doldrums Fracture Zone, Central Atlantic. Nauka, Moscow, 224 p. [in Russian].

36. QGIS Development Team (2021), QGIS Geographic Information System. Open Source Geospatial Foundation Project. http://qgis.osgeo.org

37. Rhein, M., L. Stramma, G. Krahmann (1998), The spreading of Antarctic bottom water in the tropical Atlantic. Deep Sea Research Part I: Oceanographic Research Papers, 45, No. 4-5, 507-527.

38. Rhein, M., L. Stramma, U. Send (1995), The Atlantic deep western boundary current: Wa-ter masses and transports near the equator. Journal of Geophysical Research: Oceans, 100, No. C2, 2441-2457.

39. Seabrooke, J. M., G. L. Hufford, R. B. Elder (1971), Formation of Antarctic bottom water in the Weddell Sea. Journal of Geophysical Research, 76, No. 9, 2164-2178.

40. Tozer, B., D. T. Sandwell, et al. (2019), Global bathymetry and topography at 15 arc sec-onds: SRTM15+, Accepted Earth and Space Science (accessed on 20.01.2021): https://topex.ucsd.edu/cgi-bin/get_srtm15.cgi.

41. Troupin, C., Machin, F., Ouberdous, M., Sirjacobs, D., Barth, A., & Beckers, J. M. (2010), High-resolution climatology of the northeast Atlantic using Data-Interpolating Var-iational Analysis (DIVA). Journal of Geophysical Research: Oceans, 115, No. C8.

42. van Rossum, G., F. L. Drake Jr (1995), Python tutorial (Vol. 620). Amsterdam: Centrum voor Wiskunde en Informatica.

43. Vangriesheim, A. (1980), Antarctic bottom water flow through the Vema fracture zone. Oceanologica Acta, 3, No. 2, 199-207.

44. Whitehead, J. A. (1998), Topographic control of oceanic flows in deep passages and straits. Reviews of geophysics, 36, No. 3, 423-440.

45. Whitehead, J. A., Worthington, L. V. (1982), The flux and mixing rates of Antarctic Bot-tom Water within the North Atlantic. Journal of Geophysical Research: Oceans, 87, No. C10, 7903-7924.

46. WOCE Hydrographic Programme, WHP (2002): Physical oceanography during L'ATA-LANTE cruise 35A3CITHER1_2 on section A06. PANGAEA, https://doi.org/10.1594/PANGAEA.293965

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