A model of Black Sea circulation with strait exchange (2008–2018)

Abstract

Abstract. The Bosphorus exchange is of critical importance for hydrodynamics and hydroclimatology of the Black Sea. In this study, we report on the development of a medium-resolution circulation model of the Black Sea, making use of surface atmospheric forcing with high space and time resolution, climatic river fluxes and strait exchange, enabled by adding elementary details of strait and coastal topography and seasonal hydrology specified in an artificial box on the Marmara Sea side. Particular attention is given to circulation, mixing and convective water mass formation processes in the model, which are then compared with observations. Open boundary conditions relaxed to seasonal hydrology specified in the artificial box are found to enable Bosphorus exchange with a proper upper layer, lower layer and net fluxes comparable to the observed ranges. These improvements at the artificial boundary and in the interior evolution of the Black Sea allow the study to capture daily, seasonal to decadal climatic variability and change observed in the Black Sea in the last few decades.

Caspian Sea and Black Sea Response to Greenhouse Warming in a High‐Resolution Global Climate Model

“…The Black Sea is a meromictic basin, which maintains anoxic conditions below 200 m, due to the lack of deep mixing. Wind stress and thermohaline forcing drive a persistent cyclonic shelf‐rim current around the Black Sea as well as multi‐cell interior cyclonic circulation gyres (Gunduz et al., 2020; Oguz et al., 1993, 1995; Simonov & Altman, 1991; Stanev, 1990). Other key features of the Black Sea circulation include an active mesoscale eddy field (Enriquez et al., 2005; Ginzburg et al., 2002; Kubryakov & Stanichny, 2015) and quasi‐stationary coastal eddies, which play an important role in the water exchange between coastal regions and the interior (Staneva et al., 2001).…”

Spreading of Lagrangian Particles in the Black Sea: A Comparison between Drifters and a High-Resolution Ocean Model

“…where r (1) and r (2) are the Lagrangian arc length of the particle trajectories forming the pair, t is the time and D 0 is the initial pair separation distance.…”

“…where V (1) and V (2) are the Lagrangian velocities of two drifters separated with a predefined distance.…”

“…In its southwestern region, the BS is connected with the Mediterranean Sea by the Bosphorus Strait, through which a small amount of salty water flows into the BS. Despite its small size, the Bosphorus Strait plays a critical role for the hydrodynamics and climatology of the BS [1]. In the northwestern BS area, the inflow of freshwaters (low-salinity waters) from large rivers (e.g., Danube, Dnepr and Dnestr rivers) leads to the generation of a pycnocline near 100-150 m, which inhibits exchanges between the surface and deep waters [2].…”

NEMO-Bohai 1.0: a high-resolution ocean and sea ice modelling system for the Bohai Sea, China

“…applications from short-term forecasts and climate projections (Drouard and Cassou, 2019;Obermann-Hellhund et al, 2018;Uotila et al, 2017;Voldoire et al, 2013) to process studies (Courtois et al, 2017;Declerck et al, 2016;Feucher et al, 2019). While global models offer a poor representation of regional ocean processes, regional models have been developed based on the framework of NEMO in recent years, 90 e.g., models for the Atlantic marginal basins (Graham et al, 2018;O'Dea et al, 2017), the Baltic and North seas (Hordoir et al, 2019;Pemberton et al, 2017), the Northwestern Mediterranean Sea (Declerck et al, 2016), the South Indian Ocean (Schwarzkopf et al, 2019), the South China Sea (Thompson et al, 2019), and the Black Sea (Gunduz et al, 2020). However, a regional model for the Bohai Sea based on NEMO has not yet been developed, until now.…”