Multi-sensor in situ observations to resolve the sub-mesoscale features in the stratified Gulf of Finland, Baltic Sea
Autor: | Taavi Liblik, Inga Lips, Urmas Lips, Villu Kikas |
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Jazyk: | angličtina |
Rok vydání: | 2016 |
Předmět: |
0106 biological sciences
lcsh:GE1-350 010504 meteorology & atmospheric sciences 010604 marine biology & hydrobiology Baroclinity Mesoscale meteorology lcsh:Geography. Anthropology. Recreation General Medicine Structural basin 01 natural sciences Oceanography Eddy lcsh:G Downwelling Climatology Energy cascade Upwelling Thermocline Geology lcsh:Environmental sciences 0105 earth and related environmental sciences |
Zdroj: | Ocean Science, Vol 12, Iss 3, Pp 715-732 (2016) |
ISSN: | 1812-0792 1812-0784 |
Popis: | High-resolution numerical modeling, remote sensing, and in situ data have revealed significant role of sub-mesoscale features in shaping the distribution pattern of tracers in the ocean's upper layer. However, in situ measurements are difficult to conduct with the required resolution and coverage in time and space to resolve the sub-mesoscale, especially in such relatively shallow basins as the Gulf of Finland, where the typical baroclinic Rossby radius is 2–5 km. To map the multi-scale spatiotemporal variability in the gulf, we initiated continuous measurements with autonomous devices, including a moored profiler and Ferrybox system, which were complemented by dedicated research-vessel-based surveys. The analysis of collected high-resolution data in the summers of 2009–2012 revealed pronounced variability at the sub-mesoscale in the presence of mesoscale upwelling/downwelling, fronts, and eddies. The horizontal wavenumber spectra of temperature variance in the surface layer had slopes close to −2 between the lateral scales from 10 to 0.5 km. Similar tendency towards the −2 slopes of horizontal wavenumber spectra of temperature variance was found in the seasonal thermocline between the lateral scales from 10 to 1 km. It suggests that the ageostrophic sub-mesoscale processes could contribute considerably to the energy cascade in such a stratified sea basin. We showed that the intrusions of water with different salinity, which indicate the occurrence of a layered flow structure, could appear in the process of upwelling/downwelling development and relaxation in response to variable wind forcing. We suggest that the sub-mesoscale processes play a major role in feeding surface blooms in the conditions of coupled coastal upwelling and downwelling events in the Gulf of Finland. |
Databáze: | OpenAIRE |
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