Журнал

About Editorial Board Information for authors and reviewers Publication ethics Contacts User Account: send / review a manuscript
Archive
Volume 22, 2025
Номер 1
Volume 21, 2024
Number 1 Number 2 Number 3 Number 4 Number 5 Number 6
Volume 20, 2023
Number 1 Number 2 Number 3 Number 4 Number 5 Number 6
Volume 19, 2022
Number 1 Number 2 Number 3 Number 4 Number 5 Number 6
Volume 18, 2021
Number 1 Number 2 Number 3 Number 4 Number 5 Number 6
Volume 17, 2020
Number 1 Number 2 Number 3 Number 4 Number 5 Number 6 Number 7
Volume 16, 2019
Number 1 Number 2 Number 3 Number 4 Number 5 Number 6
Volume 15, 2018
Number 1 Number 2 Number 3 Number 4 Number 5 Number 6 Number 7
Volume 14, 2017
Number 1 Number 2 Number 3 Number 4 Number 5 Number 6 Number 7
Volume 13, 2016
Number 1 Number 2 Number 3 Number 4 Number 5 Number 6
Volume 12, 2015
Number 1 Number 2 Number 3 Number 4 Number 5 Number 6
Volume 11, 2014
Number 1 Number 2 Number 3 Number 4
Volume 10, 2013
Number 1 Number 2 Number 3 Number 4
Volume 9, 2012
Number 1 Number 2 Number 3 Number 4 Number 5
Volume 8, 2011
Number 1 Number 2 Number 3 Number 4
Volume 7, 2010
Number 1 Number 2 Number 3 Number 4
Issue 6, 2009
Volume 1 Volume 2
Issue 5, 2008
Volume 1 Volume 2
Issue 4, 2007
Volume 1 Volume 2
Issue 3, 2006
Volume 1 Volume 2
Issue 2, 2005
Volume 1 Volume 2
Issue 1, 2004
Volume 1
Search
Find:
русский
ISSN 2070-7401 (Print), ISSN 2411-0280 (Online)
Sovremennye problemy distantsionnogo zondirovaniya Zemli iz kosmosa
CURRENT PROBLEMS IN REMOTE SENSING OF THE EARTH FROM SPACE

  

Sovremennye problemy distantsionnogo zondirovaniya Zemli iz kosmosa, 2025, Vol. 22, No. 1, pp. 221-234

Hydrophysical processes in the vicinity of Ampère Seamount based on in situ measurements and satellite data

V.A. Melnikov 1 
1 P.P. Shirshov Institute of Oceanology RAS, Moscow, Russia
Accepted: 03.12.2024
DOI: 10.21046/2070-7401-2025-22-1-221-234
A description of multiscale hydrodynamic processes developing in the waters near of the Ampère Seamount in the Northeastern Atlantic is given. Interpretations are based on the joint analysis of hydrophysical measurements carried out in January – February, 1985, during the Shirshov Institute of Oceanology RAS expedition on board the research vessel Rift (5th cruise) and up-to-date satellite data. During the expedition, hydrological sections using a towed CTD (Conductivity, Temperature, Depth) probe, hydrological measurements at the vessel’s anchorage at the Ampère Bank, and measurements of currents at a buoy station were made. Materials of some other expeditions that took place in the Ampère Bank aquatorium were also considered. Satellite data arrays on sea surface temperature (Pathfinder Sea Surface Temperature (SST)); long term sea-level and geostrophic velocity series of Archiving, Validation and Interpretation of Satellite Oceanographic data (AVISO), Sea Surface Height (SSH) Products; World bank of hydrological stations World Ocean Database 2013 (WOD 13) data; and Earth TOPOgraphy (ETOPO) 2022 global bottom relief model dataset with 15 arcseconds resolution were used in the analysis of hydrophysical processes. It is shown that complex hydrological fields in the vicinity of the Ampère Seamount are caused by multiscale hydrophysical processes in the region of the eastern branch of the Azores Current. On the ocean surface, a large-scale drift with a speed of ~5.54±0.05 cm/s, mostly eastward, is observed. In the field of mixing of subtropical waters and waters of temperate latitudes, meanders and eddies of various shapes and sizes develop. The kinetic energy density of geostrophic flows averages 87±1 erg/cm3. Sporadically, for an unexplained reason, there are “flashes” of currents in which the energy increases by almost an order of magnitude (to 610 erg/cm3). Three groups of cyclic fluctuations of currents are distinguished: perennial, annual, and intra-annual, as well as the chaotic background component of the oscillations. There is a significant intermittency in power and frequency of all of these components. According to contact measurements, the following phenomena have been observed in the subsynoptic interval of scales: a local front with a flow along it; dipole eddies ~15–30 km in size; wave-like structures with a wavelength of ~12–8 km in the southern sector of the mountain; a mosaic density over the mountain with a spot scale of the order of the size of the bank (~10–12 km); as well as temperature jumps over the bank. The following scheme of hydrophysical processes in the vicinity of the Ampère Seamount is proposed. In winter season, as a result of supposedly meteorological influence, a local front can (rarely) form, giving rise to an average current of ~30 cm/s to the south. Downstream the bank, lee internal waves with a limited length that is close to the scale of inertial oscillation swept away by the flow arise. Dipole subsynoptic vortices occur due to frontal instability. Tidal currents cause frontal boundary displacements, which manifest themselves as large temperature semi-diurnal fluctuations. Directly over the bank, colder deep waters are transported by tidal currents along the mount slopes to its top. As a result, a specific mosaic field is formed and temperature jumps followed by high-frequency (~20 min) oscillations are observed.
Keywords: Ampère Seamount, Azores Current, satellite data, hydrological front, tidal currents, temperature jumps, 20-minute oscillation packets, internal lee waves
Full text

References:

  1. Gamsakhurdiya G. R., Mel’nikov V. A., Paramonov A. N., Spatial features and temporary changes in hydrological fields in the Ampere Bank area, Okeanologicheskie issledovaniya, 1990, No. 43, pp. 73–82 (in Russian).
  2. Golubev Yu. N., Cherkesov L. V., Ehksperimental’nye issledovaniya vnutrennikh voln nad bankoi Amper: preprint (Experimental studies of internal waves over the Ampere bank: Preprint), Sevastopol’: MGI AN USSR, 1985, 33 p. (in Russian).
  3. Ivanov Yu. A., Mel’nikov V. A., Novitskii A. G., Stratified flow over the bottom irregularities, Izvestiya AN SSSR. Ser. Fizika atmosfery i okeana, 1977, V. 13, No. 12, pp. 1278–1286 (in Russian).
  4. Mel’nikov V. A., Features of multiscale variations in geophysical continuous media, Process in GeoMedia, 2015, V. 2, No. 3, pp. 41–49 (in Russian).
  5. Monin A. S., Ozmidov R. V., Paka V. T., On the mesostructure of the flow around seamounts, Doklady AN SSSR, 1989, V. 308, No. 1, pp. 192–196 (in Russian).
  6. Arhan M., Colin de Verdiére A., Mémery L., The eastern boundary of the subtropical North Atlantic, J. Physical Oceanography, 1994, V. 24, pp. 1295–1316, DOI: 10.1175/1520-0485(1994)024<1295:TEBOTS>2.0.CO;2.
  7. Lavelle J. W., Mohn C., Motion, commotion,and biophysical connections at deep ocean seamounts, Oceanography, 2010, V. 23, No. 1, pp. 90–103.
  8. Melnikov V. A., Hydrophysical processes in the vicinity of Ampere Seamount, Geophysical Research Abstracts, Vienna: EGU General Assembly, 2009, V. 11, Article EGU2009-9869.
  9. Morato T., Hoyle S. D., Allain V., Nicol S. J., Seamounts are hotspots of pelagic biodiversity in the open ocean, Proc. National Academy of Sciences, 2010, V. 107, No. 21, pp. 9707–9711, DOI: 10.1073/pnas.0910290107.
  10. Roden G. I., Effects of seamounts and seamount chains on ocean circulation and thermohaline structure, In: Seamounts, Islands, and Atolls, Keating B. H., Fryer P., Batzia R., Boehlert G. W. (eds.), Geophysical. Monograph Ser., V. 43, AGU, Washington, 1987, pp. 335–354, DOI: 10.1029/GM043p0335.
  11. Smith W. H. F., Sandwell D. T., Global seafloor topography from satellite altimetry and ship depth soundings, Science, 1997, V. 277, pp. 1957–1962, http://dx.doi.org/10.1126/science.277.5334.1956.
  12. van Aken H. M. (2000a), The hydrography of the mid-latitude northeast Atlantic Ocean. I. The deep water masses, Deep Sea Research Part I: Oceanographic Research Papers, 2000, V. 47, Iss. 5, pp. 757–788, DOI: 10.1016/S0967-0637(99)00092-8.
  13. van Aken H. M. (2000b), The hydrography of the mid-latitude northeast Atlantic Ocean. II. The intermediate water masses, Deep Sea Research Part I: Oceanographic Research Papers, 2000, V. 47, Iss. 5, pp. 789–824, DOI: 10.1016/S0967-0637(99)00112-0.
  14. van Aken H. M., The hydrography of the mid-latitude northeast Atlantic Ocean — Part III: The subducted thermocline water mass, Deep Sea Research Part I: Oceanographic Research Papers, 2001, V. 48, Iss. 1, pp. 237–267, DOI: 10.1016/S0967-0637(00)00059-5.
  15. Vlasenko V., Stashchuk N., Palmer M. R., Inall M. E., Generation of baroclinic tides over an isolated underwater bank, J. Geophysical Research: Oceans, 2013, V. 118, Iss. 9, pp. 4395–4408, DOI: 10.1002/jgrc.20304.