Seasonal resonance of diurnal coastal trapped waves in the southern Weddell Sea, Antarctica
-
Published:2017-01-30
Issue:1
Volume:13
Page:77-93
-
ISSN:1812-0792
-
Container-title:Ocean Science
-
language:en
-
Short-container-title:Ocean Sci.
Author:
Semper StefanieORCID, Darelius Elin
Abstract
Abstract. The summer enhancement of diurnal tidal currents at the shelf break in the southern Weddell Sea is studied using velocity measurements from 29 moorings during the period 1968 to 2014. Kinetic energy associated with diurnal tidal frequencies is largest at the shelf break and decreases rapidly with distance from it. The diurnal tidal energy increases from austral winter to summer by, on average, 50 %. The austral summer enhancement is observed in all deployments. The observations are compared to results from an idealised numerical solution of the properties of coastal trapped waves (CTWs) for a given bathymetry, stratification and an along-slope current. The frequency at which the dispersion curve for mode 1 CTWs displays a maximum (i.e. where the group velocity is zero and resonance is possible) is found within or near the diurnal frequency band, and it is sensitive to the stratification in the upper part of the water column and to the background current. The maximum of the dispersion curve is shifted towards higher frequencies, above the diurnal band, for weak stratification and a strong background current (i.e. austral winter-like conditions) and towards lower frequencies for strong upper-layer stratification and a weak background current (austral summer). The seasonal evolution of hydrography and currents in the region is inferred from available mooring data and conductivity–temperature–depth profiles. Near-resonance of diurnal tidal CTWs during austral summer can explain the observed seasonality in tidal currents.
Publisher
Copernicus GmbH
Subject
Cell Biology,Developmental Biology,Embryology,Anatomy
Reference74 articles.
1. Årthun, M., Nicholls, K. W., Makinson, K., Fedak, M. A., and Boehme, L.: Seasonal inflow of warm water onto the southern Weddell Sea continental shelf, Antarctica, Geophys. Res. Lett., 39, L17601, https://doi.org/10.1029/2012GL052856, 2012. 2. Boehme, L., Lovell, P., Biuw, M., Roquet, F., Nicholson, J., Thorpe, S. E., Meredith, M. P., and Fedak, M.: Technical Note: Animal-borne CTD-Satellite Relay Data Loggers for real-time oceanographic data collection, Ocean Sci., 5, 685–695, https://doi.org/10.5194/os-5-685-2009, 2009. 3. Brink, K. H.: Coastal-trapped waves and wind-driven currents over the continental shelf, Annu. Rev. Fluid Mech., 23, 389–412, https://doi.org/10.1146/annurev.fl.23.010191.002133, 1991. 4. Brink, K. H.: Coastal-Trapped Waves with Finite Bottom Friction, Dynam. Atmos. Oceans, 41, 172–190, https://doi.org/10.1016/j.dynatmoce.2006.05.001, 2006. 5. British Antarctic Survey: UK Antarctic Surface Meteorology; 1947–2013, Database, Version 1.0, Polar Data Centre, British Antarctic Survey, updated 2014, https://doi.org/10.5285/569d53fb-9b90-47a6-b3ca-26306e696706, 2013.
Cited by
22 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献
|
|