Operative forecast of hydrophysical fields in the Georgian Black Sea coastal zone within the ECOOP

Abstract. One of the part of the Black Sea Nowcasting/Forecasting System is the regional forecasting system for the Easternmost part of the Black Sea (including the Georgian water area), which have been developed within the context of the EU International projects ARENA and ECOOP. A core of the regional system is a high-resolution baroclinic regional model of the Black Sea dynamics developed at M. Nodia Institute of Geophysics (RM-IG). This model is nested in the basin-scale model (BSM) of Marine Hydrophysical Institute (MHI, Sevastopol/Ukraine). The regional area is limited to the Caucasian and Turkish coastal lines and the western liquid boundary coinciding with a meridian 39.36° E. Since June 2010 we regularly compute 3 days' forecasts of current, temperature and salinity for the Easternmost part of the Black Sea with 1 km spacing. In this study results of two forecasts are presented. The first forecast corresponds to Summer season and covers the prognostic interval from 00:00 h, 6 August to 00:00 h, 9 August 2010. The second one corresponds to Autumn season and covers the prognostic interval from 00:00 h, 26 October to 00:00 h, 29 October 2010. Data needed for the forecasts – the 3-D initial and prognostic hydrophysical fields, also 2-D prognostic meteorological fields at the sea surface, wind stress, heat fluxes, evaporation and precipitation rates for the our regional area are placing on the MHI server every day and we are available to use these data operatively. Prognostic hydrophysical fields are results of forecast by BSM of MHI and 2-D meteorological boundary fields represent results of forecast by regional atmospheric model ALADIN. All these fields are given on the grid of BSM with 5 km spacing and with one-hour time step frequency for the integration period. The analysis of predicted fields shows that to use the model with high resolution is very important factor for identification of nearshore eddies of small sizes. It should be noted very different character of regional circulation in summer and autumn seasons in the Easternmost part of the Black Sea.

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Operational forecast of hydrophysical fields in the Georgian Black Sea coastal zone within the ECOOP

Ocean Science ◽

10.5194/os-7-793-2011 ◽

2011 ◽

Vol 7 (6) ◽

pp. 793-803 ◽

Cited By ~ 12

Author(s):

A. A. Kordzadze ◽

D. I. Demetrashvili

Keyword(s):

High Resolution ◽

Black Sea ◽

Surface Wind ◽

Scale Model ◽

Open Boundary ◽

The Black Sea ◽

Time Step ◽

Regional Area ◽

Basin Scale ◽

Forecasting System

Abstract. One of the parts of the Black Sea Nowcasting/Forecasting System is the regional forecasting system for the easternmost part of the Black Sea (including the Georgian water area), which has been developed within the context of the EU International projects ARENA and ECOOP. A core of the regional system is a high-resolution baroclinic regional model of the Black Sea dynamics developed at M. Nodia Institute of Geophysics (RM-IG). This model is nested in the basin-scale model of Marine Hydrophysical Institute (MHI, Sevastopol/Ukraine). The regional area is limited to the Caucasian and Turkish coastal lines and the western liquid boundary coinciding with the meridian 39.36° E. Since June 2010 we have regularly been computing 3 days' forecasts of current, temperature and salinity for the easternmost part of the Black Sea with 1 km spacing. In this study the results of two forecasts are presented. The first forecast corresponds to summer season and covers the prognostic interval from 00:00 h, 6 August to 00:00 h, 9 August 2010. The second one corresponds to autumn season and covers the prognostic interval from 00:00 h, 26 October to 00:00 h, 29 October 2010. Data needed for the forecasts – the initial and prognostic hydrophysical fields on the open boundary, also 2-D prognostic meteorological fields at the sea surface – wind stress, heat fluxes, evaporation and precipitation rates for our regional area are being placed on the MHI server every day and we are available to use these data operatively. Prognostic hydrophysical fields are results of forecast by the basin-scale model of MHI and 2-D meteorological boundary fields represent the results of forecast by regional atmospheric model ALADIN. All these fields are given on the grid of basin-scale model with 5 km spacing and with one-hour time step frequency for the integration period. The analysis of predicted fields shows that to use the model with high resolution is very important factor for identification of nearshore eddies of small sizes. It should be noted the very different character of regional circulation in summer and autumn seasons in the easternmost part of the Black Sea.

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Evaluation of the new high resolution unstructured grid Marmara Sea model

10.5194/egusphere-egu21-7194 ◽

2021 ◽

Author(s):

Mehmet Ilicak ◽

Ivan Federico ◽

Ivano Barletta ◽

Nadia Pinardi ◽

Stefania Angela Ciliberti ◽

...

Keyword(s):

High Resolution ◽

Boundary Conditions ◽

Black Sea ◽

Mixed Layer ◽

Unstructured Grid ◽

The Black Sea ◽

Marmara Sea ◽

Lateral Boundary ◽

Lateral Boundary Conditions ◽

Forecasting System

<p>Marmara Sea including Bosphorus and Dardanelles Straits (i.e. Turkish Strait Systems, TSS) is the connection between the Black Sea and the Mediterranean. The exchange flow that occurs in the Straits is crucial to set the deep water properties in the Black Sea and the surface water conditions in the Northern Aegean Sea. We have developed a new high-resolution unstructured grid model (U-TSS) for the Marmara Sea including the Bosporus and Dardanelles Straits using the System of HydrodYnamic Finite Element Modules (SHYFEM). Using an unstructured grid in the horizontal better resolves geometry of the Turkish Straits. The new model has a resolution between 500 meter in the deep to 50 meter in the shallow areas, and 93 geopotential coordinate levels in the vertical. We conducted a 4 year hindcast simulation between 2016 and 2019 using lateral boundary conditions from CMEMS (https://marine.copernicus.eu/) analysis, in particular Black Sea Forecasting System (BS-FS) for the northern boundary and Mediterranean Sea Forecasting System (MS-FS) for the southern boundary. Atmospheric boundary conditions fare from the ECMWF dataset.</p><p>Mean averaged surface circulation shows that there is a cyclonic gyre in the middle of the basin due to Bosphorus jet flowing to the south and turning to west after reaching the southern Marmara coast. The U-TSS model has been validated against the seasonal in situ observations obtained from four different cruises between 2017 and 2018. The maximum bias occurs at around halocline depth between 20 to 30 meters. &#160;We also found that root mean square error field is higher in the mixed layer interface. We conclude that capturing shallow mixed layer depth is very in the Marmara Sea due to the interplay of air-sea fluxes and mixing parametrizations uncertainties. Maximum salinity bias and rms in the new U-TSS model are around 3 psu which is a significant improvement with respect to previous studies. This new model will be used as an operational forecasting system and will provide lateral boundary conditions for the BS-FS and MS-FS models in the future.</p>

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MARINE FORECAST FOR THE EASTERNMOST PART OF THE BLACK SEA

10.32008/geolinks2021/b1/v3/50 ◽

2021 ◽

Author(s):

Demuri Demetrashvili ◽

Vepkhia Kukhalashvili ◽

Diana Kvaratskhelia ◽

Aleksandre Surmava

Keyword(s):

Black Sea ◽

Splitting Method ◽

Equation System ◽

Water Area ◽

Regional Model ◽

Scale Model ◽

The Black Sea ◽

Marine Hydrophysical Institute ◽

Basin Scale ◽

Short Term Forecasting

Modelling and forecasting of dynamic processes and distribution of various substances of anthropogenic and natural origin in coastal and shelf zones of the seas and oceans are of great interest due to the high anthropogenic load of these zones. The aim of this paper is to present some examples of modelling and short-term forecasting of dynamic fields – the current, temperature and salinity in the easternmost Black Sea covering Georgian sector of the Black Sea and adjacent water area using a high-resolution regional model of the Black Sea dynamics. The z-level regional model is based on a full system of ocean hydro-thermodynamics equations and is nested in the basin-scale model of the Black Sea dynamics of Marine Hydrophysical Institute (Sevastopol). To solve the model equation system, a numerical algorithm based on the splitting method is used. Calculations show that circulation processes in the easternmost water area of the Black Sea are characterized by a permanent alternation of different circulation modes with the formation of mesoscale and submesoscale eddies throughout the year, which significantly affect the formation of thermohaline fields; atmospheric wind forcing substantially determines not only the peculiarities of the sea surface horizontal circulation, also the vertical structure of the current field.

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MODELING OF DYNAMIC PROCESSES IN THE BLACK SEA AND ATMOSPHERE IN PERSPECTIVE OF THEIR COUPLING FOR THE BLACK SEA REGION

10.32008/geolinks2021/b2/v3/16 ◽

2021 ◽

Author(s):

Demuri Demetrashvili ◽

Aleksandre Surmava ◽

Vepkhia Kukhalashvili

Keyword(s):

Black Sea ◽

Atmospheric Dynamics ◽

Scale Model ◽

Necessary Condition ◽

The Black Sea ◽

Limited Area ◽

Full System ◽

The Caucasus ◽

Caucasus Region ◽

Basin Scale

"At the modern stage of the development of Geosciences, the study of hydrothermodynamic and ecological processes occurring in the natural environment (sea, atmosphere, soil), their monitoring and forecasting become very relevant and are a necessary condition for sustainable development of society. The Caucasus region is one of the most difficult regions of the world from the point of view its physical and geographical features. These features include the Black and Caspian Seas and the complex terrain of the Caucasus. The Seas and the atmosphere are unified hydrodynamic systems, between subsystems of which processes of an exchange of energies, momentum and substances continuously take place. One of the most effective ways to study natural and environmental processes is methods of mathematical modeling, which allows reproducing these processes and phenomena and studying the quantitative contribution of various factors to the development of such processes. The purpose of the paper is to discuss the models of the Black Sea and atmospheric dynamics developed at M. Nodia Institute of Geophysics of I. Javakhishvili Tbilisi State University, and some results of their implementation. The model of the Black Sea dynamics is based on a full system of ocean hydro-thermodynamics equations. Its high-resolution version, which is nested in the basin-scale model of the Black Sea dynamics of Marine Hydrophysical Institute (MHI, Sevastopol), is used to forecast main hydrophysical fields for the easternmost part of the Black Sea. The model of the atmospheric dynamics is based on a full system of atmospheric hydro-thermodynamics equations in hydrostatic approximation written in the terrain-following coordinate system and is realized for the extended territory including the eastern part of the Mediterranean Sea and Black and Caspian seas and for the Caucasus region. These models, after some modification will form the basis of the coupled Black Sea-atmosphere limited-area modeling system."

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MODELING OF VARIABILITY OF THE REGIONAL DYNAMIC PROCESSES DEVELOPED DURING 2017-2019 IN THE EASTERNMOST PART OF THE BLACK SEA

GEOLINKS Conference proceedings, Book 2 Volume 2 ◽

10.32008/geolinks2020/b2/v2/10 ◽

2020 ◽

Author(s):

Demuri Demetrashvili ◽

Vepkhia Kukhalashvili ◽

Aleksandre Surmava ◽

Diana Kvaratskhelia

Keyword(s):

Black Sea ◽

Practical Interest ◽

Temporal Distribution ◽

Scale Model ◽

Dynamic Processes ◽

The Black Sea ◽

Coastal Zones ◽

Marine Hydrophysical Institute ◽

Regional Dynamic ◽

Basin Scale

The study of water circulation and thermohaline processes in the coastal zones of the seas and oceans, subjected to the most intense anthropogenic press, is an important problem of modern Oceanology. According to experimental and theoretical researches the coastal water areas of the Black Sea are dynamically active regions, where intensive generation of mesoscale and submesoscale eddies takes place. Such eddies make a significant contribution to the horizontal and vertical transport of different polluting substances, heat, momentum, etc. Therefore, the modeling and study of main peculiarities of variability of regional dynamic processes is of great scientific and practical interest. The goal of this study is to investigate numerically the structure and spatial –temporal distribution of the sea flow and thermohaline fields taking place during the period 2017-2019 in the easternmost part of the Black Sea, which is limited from the open part of the sea basin with liquid boundary coinciding 39.080E. With this purpose a high-resolution numerical regional model of the Black Sea dynamics of M. Nodia Institute of Geophysics of I. Javakhishvili Tbilisi State University (RM-IG) is used. The RM-IG is nested in the basin-scale model of the Black Sea dynamics of Marine Hydrophysical Institute (Sevastopol) and is based on a primitive system of ocean hydrothermodynamics equations. The RM-IG uses a calculated grid having 215x347 points on horizons with 1 km spatial resolution. Results of researches presented in the paper show significant variability of the regional dynamic processes in the easternmost water area during 2017-2019, where continuously generation, deformation and disappearance of the cyclonic and anticyclonic vortex formations of difference sizes takes plac

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Updated System for the Sea Wave Operational Forecast of the Black Sea Marine Forecasting Center

Physical Oceanography ◽

10.22449/1573-160x-2021-5-579-595 ◽

2021 ◽

Vol 28 (5) ◽

Author(s):

Yu. B. Ratner ◽

V. V. Fomin ◽

A. L. Kholod ◽

A. M. Ivanchik ◽

◽

...

Keyword(s):

Black Sea ◽

Functional Dependence ◽

Surface Wind ◽

The Black Sea ◽

Swan Model ◽

Wave Forecast ◽

Wave Heights ◽

Forecasting System ◽

Model Tuning ◽

Sea Wave

Purpose. The work is aimed at updating the sea wave forecasting system developed in the Black Sea Marine Forecasting Center by including the block of wind wave forecast in the Sevastopol region and by improving the wave forecast accuracy using the proposed procedure for the SWAN model tuning. Methods and Results. In the updated forecasting system, the possibility of performing the joint operational sea wave forecasts for the Black Sea and the Sevastopol region (with the 5 and 1 km spatial resolutions, respectively) became possible due to the nested grid method applied. To improve accuracy of the wave forecasts, the procedure for the SWAN model tuning was proposed. It is based on changing the parameterization of the surface friction coefficient Cd(V), where V is the surface wind speed. This permits to reduce the deviations of the forecasted wave heights from those obtained from the satellite altimetry measurements. Efficiency of the proposed procedure was assessed through comparison of the forecasting results with the remote sensing data. It is shown that in the forecasts supplied with an optimal choice of functional dependence Cd(V), the scattering index between the forecasted and measured values can be reduced by 20 %. Conclusions. Represented is the updated system of the Black Sea Marine Forecasting Center intended for the joint operational sea wave forecasts in the Black Sea and in the Sevastopol region. The results of model validation have shown that the procedure proposed for tuning the SWAN model makes it possible to reduce the deviations of the forecasted wave heights from those measured by the sensors installed at the altimetry satellites.

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