Analysis of the circulation and shelf-slope exchanges in the continental margin of the northwestern Mediterranean

Abstract

Abstract. In this paper, we present the results from a high horizontal resolution numerical simulation of the northwestern Mediterranean using a z-level, non-hydrostatic, primitive equation ocean model (DieCAST). The high resolution allows an accurate representation of the submarine canyons that presides in the region. The model is one-way coupled to a large scale model of the Mediterranean Sea through open boundaries and uses the atmospheric forcing fields provided in terms of HIRLAM outputs by the Spanish National Institute of Meteorology. Results show that the model can successfully reproduce the complex general circulation characteristics of the area, including the modifications induced by canyons in their vicinity and other phenomena observed such as instabilities and coastal trapped waves. The sea surface temperature is similar to satellite observations except that simulated temperatures are slightly warmer near the coast than observations and colder near the open boundaries. An important topic of this work is the computation of the shelfslope exchanges, which are able to renew shelf waters in a few months.

The Influence of a Submarine Canyon on the Circulation and Cross-Shore Exchanges around an Upwelling Front

“…Our results, however, show completely new findings regarding the development and evolution of frontal instabilities over a canyon due to its unique coastal upwelling setting along an eastern boundary. Previous studies have confirmed a significant increase of cross-shore and vertical motions by the effects of the interaction of an unstable meander with a submarine canyon (Jordi et al 2006(Jordi et al , 2008. Nonetheless, their configuration corresponded to a coastal front typical of buoyancy-driven currents (isopycnals tilting upward in the offshore direction).…”

“…Although shelf-slope exchanges have been widely studied and reviewed (e.g., Houghton et al 1988;Huthnance 1995;Dinniman and Klinck 2004;Brink 2016a), there is scarce information on the combined effect and/or the interaction between surface frontal instabilities and a submarine canyon. A few studies have considered the case of mesoscale instabilities over a submarine canyon under right bounded flow conditions (typical of downwelling alongshore currents; Jordi et al 2005Jordi et al , 2008, and thus, the effect of a submarine canyon over the circulation and characteristics of an upwelling front remains poorly understood. The aim of this study is to clarify this canyon effect and to quantify its impact on cross-shore exchanges for a typical eastern boundary upwelling system.…”

Regional impact of submarine canyons during seasonal upwelling

“…In the northwest Mediterranean, under downwelling conditions, Jordi et al . [] showed enhanced cross‐shelf transport near submarine canyons and calculated a flushing time for the shelf on the order of 3 months. On the southern coast of Australia, Kämpf [] showed that upwelling in shelf break canyons contributes to the formation of a pool of dense, nutrient‐rich water over the shelf, which can subsequently be upwelled to the euphotic zone.…”

Modeling Organic Carbon Accumulation Rates and Residence Times in Coastal Vegetated Ecosystems

“…Information about the reservoir residence time ( R) for the water bodies surrounding our study sites were also incorporated into the 14 C calibration, to correct for the marine reservoir effect (Stuiver & Reimer, 1993). As no R values are reported for the Balearic Islands, we assumed that water masses from the east coast of Spain and from the Algerian coast (brought by mesoscale eddies) are representative of our study sites (Jordi et al, 2006;2009;Robinson et al, 2001). Therefore, we used a reservoir residence time correction of R = 76 ± 59 yr BP, which is the mean from waters off the coast of Northern Spain and Algeria (Reimer & McCormac, 2016;Siani et al, 2016).…”