Seasonal, interannual, and mesoscale variability of the Black Sea upper layer circulation derived from altimeter data

2003 ◽  
Vol 108 (C4) ◽  
Author(s):  
Gennady Korotaev
Keyword(s):  
Black Sea ◽  
Altimeter Data ◽  
The Black Sea ◽  
Mesoscale Variability ◽  
Upper Layer Circulation

scholarly journals How Does Solar Attenuation Depth Affect the Ocean Mixed Layer? Water Turbidity and Atmospheric Forcing Impacts on the Simulation of Seasonal Mixed Layer Variability in the Turbid Black Sea*

2005 ◽  
Vol 18 (3) ◽  
pp. 389-409 ◽  
Author(s):  
A. Birol Kara ◽  
Alan J. Wallcraft ◽  
Harley E. Hurlburt
Keyword(s):  
Solar Radiation ◽  
Black Sea ◽  
Mixed Layer ◽  
Sea Surface ◽  
Shortwave Radiation ◽  
Altimeter Data ◽  
The Black Sea ◽  
Upper Ocean ◽  
Clear Water ◽  
Water Turbidity

Abstract A fine-resolution (≈3.2 km) Hybrid Coordinate Ocean Model (HYCOM) is used to investigate the impact of solar radiation attenuation with depth on the predictions of monthly mean sea surface height (SSH), mixed layer depth (MLD), buoyancy and heat fluxes, and near-sea surface circulation as well. The model uses spatially and temporally varying attenuation of photosynthetically available radiation (kPAR) climatologies as processed from the remotely sensed Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) to take water turbidity into account in the Black Sea. An examination of the kPAR climatology reveals a strong seasonal cycle in the water turbidity, with a basin-averaged annual climatological mean value of 0.19 m−1 over the Black Sea. Climatologically forced HYCOM simulations demonstrate that shortwave radiation below the mixed layer can be quite different based on the water turbidity, thereby affecting prediction of upper-ocean quantities in the Black Sea. The clear water constant solar attenuation depth assumption results in relatively deeper MLD (e.g., ≈+15 m in winter) in comparison to standard simulations due to the unrealistically large amount of shortwave radiation below the mixed layer, up to 100 W m−2 during April to October. Such unrealistic sub–mixed layer heating causes weaker stratification at the base of the mixed layer. The buoyancy gain associated with high solar heating in summer effectively stabilizes the upper ocean producing shallow mixed layers and elevated SSH over the most of the Black Sea. In particular, the increased stability resulting from the water turbidity reduces vertical mixing in the upper ocean and causes changes in surface-layer currents, especially in the easternmost part of the Black Sea. Monthly mean SSH anomalies from the climatologically forced HYCOM simulations were evaluated against a monthly mean SSH anomaly climatology, which was constructed using satellite altimeter data from TOPEX/ Poseidon (T/P), Geosat Follow-On (GFO), and the Earth Remote Sensing Satellite-2 (ERS-2) over 1993–2002. Model–data comparisons show that the basin-averaged root-mean-square (rms) difference is ≈4 cm between the satellite-based SSH climatology and that obtained from HYCOM simulations using spatial and temporal kPAR fields. In contrast, when all solar radiation is absorbed at the sea surface or clear water constant solar attenuation depth values of 16.7 m are used in the model simulations, the basin-averaged SSH rms difference with respect to the climatology is ≈6 cm (≈50% more). This demonstrates positive impact from using monthly varying solar attenuation depths in simulating upper-ocean quantities in the Black Sea. The monthly mean kPAR and SSH anomaly climatologies presented in this paper can also be used for other Black Sea studies.

On the summer mesoscale variability of the Black Sea

2001 ◽  
Vol 59 (4) ◽  
pp. 475-515 ◽  
Author(s):  
Şükrüt. Beşiktepe ◽  
Carlos J. Lozano ◽  
Allan R. Robinson
Keyword(s):  
Black Sea ◽  
The Black Sea ◽  
Mesoscale Variability

scholarly journals Quality of the Wind Wave Forecast in the Black Sea Including Storm Wave Analysis

2021 ◽  
Vol 13 (23) ◽  
pp. 13099
Author(s):  
Stanislav Myslenkov ◽  
Alexander Zelenko ◽  
Yuriy Resnyanskii ◽  
Victor Arkhipkin ◽  
Ksenia Silvestrova
Keyword(s):  
Black Sea ◽  
Wind Wave ◽  
Altimeter Data ◽  
The Black Sea ◽  
Bias Error ◽  
Regular Grid ◽  
Wavewatch Iii ◽  
Wave Forecast ◽  
Forecast Quality

This paper presents the results of wind wave forecasts for the Black Sea. Three different versions utilized were utilized: the WAVEWATCH III model with GFS 0.25 forcing on a regular grid, the WAVEWATCH III model with COSMO-RU07 forcing on a regular grid, and the SWAN model with COSMO-RU07 forcing on an unstructured grid. AltiKa satellite altimeter data were used to assess the quality of wind and wave forecasts for the period from 1 April to 31 December 2017. Wave height and wind speed forecast data were obtained with a lead time of up to 72 h. The presented models provide an adequate forecast in terms of modern wave modeling (a correlation coefficient of 0.8–0.9 and an RMSE of 0.25–0.3 m) when all statistics were analyzed. A clear improvement in the wave forecast quality with the high-resolution wind forecast COSMO-RU07 was not registered. The bias error did not exceed 0.5 m in an SWH range from 0 to 3 m. However, the bias sharply increased to −2 or −3 m for an SWH range of 3–4 m. Wave forecast quality assessments were conducted for several storm cases.

Synoptic variability in the Black Sea. Analysis of hydrographic survey and altimeter data

2001 ◽  
Vol 31 (1-3) ◽  
pp. 45-63 ◽  
Author(s):  
Elena Sokolova ◽  
Emil V. Stanev ◽  
Valery Yakubenko ◽  
Ivan Ovchinnikov ◽  
Ruben Kos'yan
Keyword(s):  
Black Sea ◽  
Altimeter Data ◽  
The Black Sea ◽  
Synoptic Variability ◽  
Hydrographic Survey

scholarly journals Interannual Variability of Sea Surface Height over the Black Sea: Relation to Climatic Patterns

2008 ◽  
Vol 12 (10) ◽  
pp. 1-11 ◽  
Author(s):  
A. Birol Kara ◽  
Charlie N. Barron ◽  
Alan J. Wallcraft ◽  
Temel Oguz
Keyword(s):  
Black Sea ◽  
Large Scale ◽  
Mesoscale Eddy ◽  
Strong Relationship ◽  
Sea Surface Height ◽  
Sea Surface ◽  
Optimal Interpolation ◽  
Altimeter Data ◽  
The Black Sea ◽  
Teleconnection Patterns

Abstract Sea surface height (SSH) variability is presented over the Black Sea during 1993–2005. The 1/4° × 1/4° resolution daily SSH fields are formed using optimal interpolation of available altimeter data. SSH variability reveals distinct maxima in the eastern and western basins, reflecting variations in the corresponding gyres. A joint examination of SSH and sea surface temperature (SST) indicates strong relationship between the two only in winter, with correlations as high as 0.6 or more. This would reflect a steric change in sea surface height due to thermal expansion averaged over a relatively deep winter mixed layer. Newly developed SSH fields also demonstrate a switch to the positive mode of SSH starting from the end of 1996 lasting ≈4 yr. Such a climatic shift is found to be strongly related to large-scale teleconnection patterns. Finally, the daily SSH and SST anomaly fields presented in this paper can supplement various applications in the Black Sea, such as examination of biological production and mesoscale eddy dynamics.

Analysis of mean and eddy energy of the Black Sea circulation derived under account the climatic and real atmospheric forcing

2021 ◽  
Author(s):  
Olga Dymova ◽  
Sergey Demyshev ◽  
Dmitry Alekseev
Keyword(s):  
Kinetic Energy ◽  
Potential Energy ◽  
Black Sea ◽  
Baroclinic Instability ◽  
Mesoscale Eddies ◽  
The Black Sea ◽  
Barotropic Instability ◽  
Mesoscale Variability ◽  
The Mean ◽  
Mean Current

<p>The aim of the work is to study the mechanisms of the Black Sea mesoscale variability based on an analysis of Lorenz energy cycles calculated from the density and currents velocity obtained by the results of three numerical experiments. An eddy-resolving z-model with a horizontal resolution of 1.6 km was used. Three experiments were carried out with different atmospheric forcing: 1) - climatic data; 2) - SKIRON data for 2011; 3) – SKIRON data for 2016. The mean current kinetic energy MKE, the eddy kinetic energy EKE, the mean available potential energy MPE, the eddy available potential energy EPE and the rates of energy conversion, generation and dissipation were considered in detail.</p><p>For all experiments the generation and dissipation rates of the MKE and EKE are close to each other, so the kinetic energy from wind dissipated inside the sea. A buoyancy work (described by the conversion between the MPE and MKE) increase the MKE. The EKE was increasing due to the energy transport from the mean current into eddies and the transport from the EPE to the EKE for all experiments. It is shown that these two energy fluxes were comparable in the experiment 1, while the ratio between of them has changed almost six times in the experiments 2 and 3. The c(MKE, EKE) prevailed in 2011, but the c(EPE, EKE) dominated in 2016.</p><p>The maps analysis of the EKE spatial distribution showed that its maximum in the climatic field was located above a continental slope and in areas of the biggest mesoscale eddies. The mesoscale variability of the climatic circulation was due to the influence of both baroclinic and barotropic instability. The zones of the EKE maximum were located in the abyssal part of the sea in the experiments 2 and 3. EKE was increasing in 2011 mainly due to the inflow from the mean current through barotropic instability. The growth of EKE in 2016 was due to conversion of EPE induced by baroclinic instability.</p><p>The difference in the EKE variability by the results of climatic and real forcing experiments is associated with the wind forcing. The contribution of the wind stress work to MKE was decreased for the experiments 2 and 3, so as a result, it was observed weakening in the mean current, intensive stream meandering and generation of mesoscale eddies not only in the coastal zones but also in the abyssal part of the sea. Thus, the Black Sea mesoscale variability is determined by barotropic instability or by the combined contribution of barotropic and baroclinic instability processes under intense wind action. The mesoscale variability is due to baroclinic instability under weak wind action.</p><p>The reported study was funded by RFBR and Government of the Sevastopol according to the research project No 18-45-920019 and the state task No. 0555-2021-0004.</p>

Sign in / Sign up

Export Citation Format

Share Document