OS4.8

The Copernicus Marine Service implemented by Mercator Ocean International (MOi) provides operational, regular, and systematic reference information on blue/white/green ocean state for the global ocean and European regional seas. The service is unique in the world for its coverage and comprehensiveness; its balance between state-of-the-art science and operational commitments; and the consistency of its portfolio where satellite and in situ observations, and 3D model simulations are proposed in coherence to describe, monitor, and forecast the ocean sate. Thirty-five thousand expert downstream services and users are connected to the service. The Copernicus Marine Service responds to public and private user needs and supports policies related to all marine and maritime sectors.

An overview of Copernicus Marine Service achievements during the period 2015-2021 will be first given. Major advances have been achieved.  The offer for the blue, green and white ocean has been regularly improved with new products and marine parameters (surface currents, waves, pH, CO2, icebergs), higher resolution and representation of more dynamical processes, improved product quality and product quality assessment, more satellite data (Sentinels) used as upstream inputs and improved algorithms,  longer time series of reprocessed in situ and satellite data and ocean reanalyses, ocean monitoring indicators and ocean state reports and new visualisation tools.  The uptake of Sentinel-1 (sea-ice, waves), Sentinel-3 (altimetry and surface currents, sea-surface temperature, ocean colour) data and Sentinel-2 (turbidity, ocean colour) has, in particular, greatly improved Copernicus Marine Service offer.  

Drivers and plans for Copernicus 2 (2021-2027) will then be presented. The objective is to further establish Copernicus Marine Service products as a worldwide reference, continue to foster the service uptake and respond to increasing and pressing user and policy needs for improved ocean monitoring and prediction capabilities. MOi in close interaction with the European Commission and member states and with the advice of its scientific and user committees has developed an ambitious plan for the next 7 years that allows a staged implementation depending on budget implementation, user needs and priorities and feasibility/maturity. Three levels of implementation have been identified: baseline, enhanced continuity and new services. Baseline will be implemented from the start of Copernicus 2 to ensure the continuity of the present service. The enhanced continuity and new services streams will build from present and future H2020 and Horizon Europe R&D projects and will be developed depending on budget and priorities. A strong priority is, in particular, to offer new services for the coastal ocean through a co-design and co-development approach between the EU Copernicus Marine Service and coastal marine services operated by member states.

The challenging issues to establish a comprehensive monitoring and forecasting of the global ocean requires international cooperation. The Copernicus Marine Service has established important partnerships (e.g., GOOS and IOC, OceanPredict, GEO and GEO Blue Planet).  The UN Decade of Ocean Science will provide a unique opportunity and framework to strengthen this very much needed international cooperation.

How to cite: Le Traon, P.-Y.: The Copernicus Marine Service: achievements and future plans, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1102, https://doi.org/10.5194/egusphere-egu22-1102, 2022.

The Copernicus Marine Service (CMEMS) Mediterranean Monitoring and Forecasting Center (MED-MFC) adopts state of the art knowledge in scientific modeling development to operationally produce Near Real Time (NRT) and Multi-year products (MYP) for the Mediterranean Sea dynamics, from currents to waves, and biogeochemistry since 2015.

The modelling systems are based on community models (NEMO, WAM and BFM), and assimilate observational In-situ and satellite CMEMS data.

During the last 6 years, the MED-MFC systems have been substantially improved with regard to: increased resolution, improved physical, biogeochemical and wave representations thanks to modelling and data assimilation upgrades. All the systems are aligned in terms of grid resolution (1/24^o), bathymetry and share the same atmospheric and river forcing fields, moreover the wave and biogeochemical systems are forced by the MED-MFC physical fields.

The consortium also assured a continuous improvement of the accuracy of the products and their quality is continuously monitored by means of comparison with respect to available insitu and satellite observations.

The focus of this work is to present the integrated MED-MFC modelling systems and the available products, their innovative skill assessment, their evolutions during the 1^st phase of Copernicus including major recent scientific achievements.  An overview of the future upgrades for the period 2022-2024 are also presented.

How to cite: Coppini, G., Clementi, E., Cossarini, G., Korres, G., Drudi, M., Aydogdu, A., Bolzon, G., Escudier, R., Feudale, L., Goglio, A. C., Grandi, A., Lazzari, P., Lecci, R., Masina, S., Pinardi, N., Pistoia, J., Salon, S., Ravdas, M., Teruzzi, A., and Zacharioudaki, A.: The Copernicus Marine Service ocean forecasting system for the Mediterranean Sea: 2015-2021 achievements and future perspectives, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12460, https://doi.org/10.5194/egusphere-egu22-12460, 2022.

In the framework of the Copernicus Marine Service (CMEMS), the Black Sea Monitoring and Forecasting Centre (BS-MFC) is the European reference service for the provision of ocean analyses, forecasts and reanalyses in the Black Sea basin. It ensures a high level of efficiency in terms of operations, science and technology for the Black Sea predictions and monitoring of the physical including waves and biogeochemical processes. This work provides an overview of the BS-MFC modelling systems together with a description of the main operational products delivered through CMEMS interfaces. The product catalogue includes near real time and multi-year datasets, including interim recently introduced in the offer and developed in the perspective of future provisioning of monitoring indicators. The BS Physics unit delivers analysis and forecast products over a domain of about 2.5 km in horizontal with 121 vertical levels, based on NEMO v4.0 online coupled to OceanVar for the assimilation of insitu and satellite observations. It implements open boundary conditions at the Marmara Sea by means of high resolution ocean fields provided by the Unstructured Turkish Straits System. The BS Biogeochemistry unit delivers near real time and multi year products over a domain of about 3 km resolution and 31 levels, based on NEMO v3.6 online coupled to BAMHBI, able to assimilate daily L3 satellite chlorophyll observation by using the Ocean Assimilation Kit developed as part of the SANGOMA project. The BS Waves unit delivers analysis and forecast products over the same domain of BS Physics. The model is based on WAM Cycle 6, forced by surface currents and sea surface height provided by the BS Physics forecasting system. BS-MFC near real time systems are forced by ECMWF IFS analysis and forecast atmospheric fields. BS-MFC multi year systems are instead forced by ECMWF ERA5 reanalysis atmospheric fields and provide past reconstruction of the ocean state in the Black Sea at the resolution of about 3 km horizontally. Since May 2021, interim datasets are also provided with the objective to support marine monitoring capacities in the area. The work focuses on the product quality assessment of relevant BS-MFC variables and on future upgrades for improving the accuracy of forecast and reanalysis.

How to cite: Peneva, E., Ciliberti, S. A., Gregoire, M., Staneva, J., Palazov, A., Coppini, G., Lecci, R., Matreata, M., Marinova, V., Masina, S., and Pinardi, N. and the Black Sea Monitoring and Forecasting Centre: Recent advancements in the evolution of the Black Sea Monitoring and Forecasting Centre, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11605, https://doi.org/10.5194/egusphere-egu22-11605, 2022.

This work presents the last version of the operational analysis and forecasting system of the physical variables and evolution plans in the Black Sea, as developed in the framework of the Copernicus Marine Service for the Black Sea Monitoring and Forecasting Centre. 

The modelling system consists of NEMO v4.0 hydrodynamical model at 1/40º resolution in horizontal and 121 vertical levels, online coupled to OceanVar for the assimilation of available insitu and satellite observations. Recently, the system has been upgraded to handle the operational historical and forecasting discharge data for the Danube River as provided by the NIHWM (Romania). Major details on the model setup and product are also available at https://resources.marine.copernicus.eu/product-detail/BLKSEA_ANALYSISFORECAST_PHY_007_001/INFORMATION. 

This contribution will focus on the description of the Black Sea Physics production unit operational capacity and on the accuracy of the delivered products by computing relevant metrics for analysis fields and forecasting skills.

How to cite: Ciliberti, S., Jansen, E., Azevedo, D., Causio, S., Ilicak, M., Gunduz, M., Matreata, M., Stefanizzi, L., Creti', S., Lecci, R., Lima, L., Aydogdu, A., Peneva, E., Coppini, G., Masina, S., and Pinardi, N.: Black Sea Physics Analysis and Forecasting System, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7369, https://doi.org/10.5194/egusphere-egu22-7369, 2022.

How to cite: Escudier, R., Reffray, G., Hamon, M., Levier, B., and Gutknecht, E.: Improving the assimilation part of the near real time system of IBI, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11410, https://doi.org/10.5194/egusphere-egu22-11410, 2022.

European coasts are often exposed to severe storms that trigger extreme water-level conditions, leading to coastal flooding and erosion. With the objective to provide useful and timely information on coastal flood risk from extreme sea level events at European scale, a proof-of-concept for a European Coastal Flood Awareness System (ECFAS) is being developed as part of a European Union’s Horizon 2020 project. ECFAS could contribute to the evolution of the Copernicus Emergency Management Service.

ECFAS uses state-of-the-art coastal monitoring and forecasting technologies and datasets suited to regional-to-local scale assessments. For its early-warning component, ECFAS capitalizes on the ocean forecasting systems operated by the Copernicus Marine Service (CMEMS). Such forecasts are combined with a coastal-stretch-specific, pre-computed flood catalog to provide a mapping of the inundation depth and extent. Consecutively, the ECFAS-Rapid and Risk and Recovery Mapping component is activated which allows an operational assessment of the socio-economic impact of marine storms.

In this presentation, we focus on the skill of the CMEMS ocean hydrodynamic models that provide the marine hazard component to the system. We apply a methodology to detect storm-driven extreme sea level events from tide-gauge records and validate the event peak representation and forecast lead time impact. For best analyses, results show satisfactory results but a general underprediction of peak magnitudes of 10% for water levels and 18% for surges across the detected storm events. In average, the models are capable of independently flagging 76% of the observed events. Forecasts show insignificant lead time impact up to a 4-day lead time, demonstrating the suitability of the systems for early warning applications. Finally, by separating the surge and tidal contributions to the extremes, we identify the source of the prediction misfits and provide recommendations for the evolution of the CMEMS forecasting models for coastal flooding applications.

The ECFAS (European Coastal Flood Awareness System) project has received funding from the EU H2020 research and innovation programme under Grant Agreement No 101004211.

How to cite: Irazoqui Apecechea, M., Melet, A., Armaroli, C., Ciavola, P., and Fernandez Montblanc, T.: European Coastal Flood Awareness System (ECFAS): forecasting extreme coastal water-levels at European scale, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5729, https://doi.org/10.5194/egusphere-egu22-5729, 2022.

A new approach for the assessment of the quality of physics analysis and forecast products (model hereafter) of the Copernicus Marine Service (CMEMS) is proposed. The method is based on the machine learning K-means clustering algorithm. The main goal of the method is to perform clustering of the bivariate model sea water temperature and salinity errors. The model errors are defined by subtracting a measured value from the corresponding model value. We use the data from in situ near real-time observations of CMEMS. Sea water temperature and salinity products are evaluated with simultaneously measured temperature and salinity data by forming a two-dimensional error space (model minus measurements) and performing a clustering procedure in it. This method enables to consider all available measurements and assigns a quantitative quality measure to each spatial location and time instant where and when the measurements exist.

The quality assessment of physics analysis and forecast products is performed for the Baltic Sea, the Atlantic - European North West Shelf, the Atlantic - Iberian Biscay Irish region, the Mediterranean Sea and the Black Sea for the year 2021. For each regional sea, there are about 100 000 to 1 000 000 simultaneous temperature and salinity data pairs available for comparison. K-means clustering of model errors was done using five clusters for each region.

An error cluster of good quality of the model (location of dominant centroid with temperature and salinity bias close to zero) made up about 50% for the Baltic Sea, 65% for the Atlantic - European North West Shelf, 70% for Mediterranean Sea and Atlantic Iberian Biscay Irish region and 90% for the Black Sea of all comparison data pairs. We would like to note that shallow coastal areas were poorly covered by measurement data, which disabled assessment of model quality there. In the Baltic Sea, spatial distribution of model errors showed that simulated temperature and salinity fields in the Gulf of Finland had lower quality than in the rest of the Baltic Sea sub basins. In the Gulf of Finland, a significant share of model errors belonged to two clusters with overestimated salinity and temperature (dS=1.8, dT=2.0 °C and dS=0.5, dT=0.8 °C). In the Atlantic - European North West Shelf and in the Atlantic - Iberian Biscay Irish region, temperature and salinity were underestimated (dT=-2.7 °C, dS=-0.3 and dT=-1.8 °C, dS=-0.2, respectively) between a depth of 1000 m and 1300 m. In the Atlantic - Iberian Biscay Irish region, the Mediterranean Sea and the Black Sea, a separate cluster emerged in each region, which indicated a severe mismatch of the model and the measured data. A good quality of physics analysis and forecast products of the CMEMS is achieved using data assimilation of measured salinity and temperature profiles, which overlap with the data used in this assessment study.

How to cite: Raudsepp, U., Maljutenko, I., Verjovkina, S., and Lagemaa, P.: An assessment of the quality of physics analysis and forecast products of the European regional seas in 2021 using K-means clustering algorithm, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8218, https://doi.org/10.5194/egusphere-egu22-8218, 2022.

For more than 23 years, the multisatellite DUACS system has been providing  high quality multi-mission altimetry Sea Level products for oceanographic applications, climate forecasting centers, geophysics and biology communities. They consist in directly usable and easy to manipulate Level 3 (along-track cross-calibrated Sea Level Anomaly SLA) and Level 4 (multiple sensors merged gridded gap-free) products. Global and regional datasets (Arctic Ocean, European Seas ...) are available.

A full reprocessing of these products is carried out almost every 3 years, based on the state-of-the-art Level 2 to Level 4 algorithms. In Decembre 2021, a new version will be available within the Copernicus Marine Environment and Monitoring Service (CMEMS) and the Copernicus Climate Change Service (C3S)  covering 28 years of altimetric data (i.e. almost a century of cumulated data using 24 altimetric missions). This version benefits from major improvements associated with new altimeter and mapping standards.

Here, we report the first results of this DUACS DT2021 multi-mission reprocessing. We first describe the main steps of the altimeter production system. Then, we discuss the characteristics and limits of the different products (C3S, CMEMS) in order to help the ocean and climate communities on their optimal use for validation, assimilation activities and other scientific studies. Several comparisons with independent datasets (along-track, drifters, tide gauges) show that a significant improvement has been achieved at mesoscale with this new version: almost 20% of SLA error reduction at wavelengths [65, 500km] and around 10% of geostrophic currents error reduction compared to the previous version (DT2018). At decadal time scale, the trend of the global mean sea level has been estimated to 3.4 +/- 0.4 mm/yr. (90% Confidence Interval), in line with other estimates and previous reprocessing DUACS-DT2018. New altimeter corrections are also available for the users (internal waves, correction for the Topex-A instrumental drift, flag ice).

How to cite: Faugère, Y., Taburet, G., Ballarotta, M., Pujol, I., Legeais, J. F., Maillard, G., Durand, C., Dagneau, Q., Lievin, M., Sanchez Roman, A., and Dibarboure, G.: DUACS DT2021: 28 years of reprocessed sea level altimetry products, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7479, https://doi.org/10.5194/egusphere-egu22-7479, 2022.

As more than 70% of the earth surface is covered by water, exchanges of heat, gases and momentum at the air-sea interface are a key part of the dynamical earth system and its evolution. The ocean surface wind plays an essential role in the exchange at the atmosphere-ocean interface. It is therefore crucial to accurately represent the wind forcing in physical ocean model simulations. Scatterometers provide high-resolution ocean surface wind observations, but have limited spatial and temporal coverage. On the other hand, numerical weather prediction (NWP) model wind fields have better coverage in time and space, but do not resolve the small-scale variability in the air-sea fluxes. In addition, Belmonte Rivas and Stoffelen (2019) documented substantial systematic errors in global NWP fields on both small and large scales, using scatterometer observations as a reference.

Trindade et al. (2020) combined the strong points of scatterometer observations and atmospheric model wind fields into ERA*, a new ocean wind forcing product. ERA* uses temporally-averaged differences between geolocated scatterometer wind data and European Centre for Medium-range Weather Forecasts (ECMWF) reanalysis fields (ERA-Interim) to correct for persistent local NWP wind vector biases. Verified against independent observations, ERA* reduced the variance of differences by 20% with respect to the uncorrected NWP fields.

We present a new hourly ocean wind forcing product that will be included in the Copernicus Marine Service (CMEMS) catalogue in 2022. To best serve the ocean modelling community, this Level-4 product will include global bias-corrected 10-m stress-equivalent wind (De Kloe et al., 2017) and surface wind stress fields at 0.125^o horizontal spatial resolution. The near real-time (NRT) version of the product is based on the ECMWF operational model (OPS*) and the reprocessed (REP) version on the ERA5 re-analysis (ERA5*). Ocean surface winds from the existing 6-hourly CMEMS L4 wind product and ERA5* were validated against observations from an independent scatterometer (Haiyang-2B). ERA5* winds show better correspondence to Haiyang-2B winds, particularly outside the tropics, where the 6-hourly product is not able to resolve the fast-moving atmospheric systems. Like any CMEMS product, the new wind product will be freely and openly available for all operational, commercial and research applications.

References:

Belmonte Rivas, M. and A. Stoffelen (2019): Characterizing ERA-Interim and ERA5 surface wind biases using ASCAT, Ocean Sci., 15, 831–852, doi: 10.5194/os-15-831-2019.

Kloe, J. de, A. Stoffelen and A. Verhoef (2017), Improved use of scatterometer measurements by using stress-equivalent reference winds, IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens. 10 (5), doi: 10.1109/JSTARS.2017.2685242.

Trindade, A., M. Portabella, A. Stoffelen, W. Lin and A. Verhoef (2020), ERAstar: A High-Resolution Ocean Forcing Product, IEEE Trans. Geosci. Remote Sens., 1-11, doi: 10.1109/TGRS.2019.2946019.

How to cite: Giesen, R., Stoffelen, A., Trindade, A., van Cranenburgh, L., and Portabella, M.: A new high-resolution ocean wind forcing product for the Copernicus Marine Service, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7624, https://doi.org/10.5194/egusphere-egu22-7624, 2022.

The Copernicus Marine Services is operationally producing forecasts and reanalysis of biogeochemical properties such as nutrients, phytoplankton biomass and carbon chemistry, in the ocean. A key part of these model products is the assimilation of observed biogeochemical properties. Both the methods for assimilating biogeochemical observations and the observation systems are constantly evolving. In this talk we will give an overview over the present capabilities of biogeochemical data assimilation within the Copernicus Marine Services. Presently, biogeochemical data assimilation services cover a range of spatial scales, from global ocean to regional seas, methods, and observations assimilated, which are based both on in situ and remote satellite measurements. We will also present the future evolution that is presently being prepared and researched within Copernicus Marine Services as well as in research projects, such as H2020 SEAMLESS. This includes exploring the prospect of assimilating new types of observations from BGC-Argo, gliders and from remote sensing.  We will also present plans for moving towards ensemble assimilation and, given the tight connection between physical and biogeochemical variability, steps towards simultaneously constraining physical and biogeochemical model properties.

How to cite: Samuelsen, A. and Teruzzi, A.: Biogeochemical data assimilation in Copernicus Marine Services - status and future evolution, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4979, https://doi.org/10.5194/egusphere-egu22-4979, 2022.

New insights on marine biogeochemical state and variability are yielded by recently available autonomous observation platforms such as the BGC-Argo floats. Additionally, the integration of BGC-Argo data and modelling systems can provide a further improvement on understanding marine biogeochemical dynamics. Indeed BGC-Argo variables can be profitably used for tuning and validation of biogeochemical models, and in data assimilation.

The Mediterranean Sea CMEMS marine forecasting system represents a convincing example of such integration: nitrate and chlorophyll BGC-Argo profiles are already assimilated providing corrections on nutrient and phytoplankton vertical dynamics, while  float oxygen data are used for validation and will be integrated in the data assimilation scheme in 2022. Despite their value, BGC float oxygen measurements are prone to uncertainties such as those related to sensor drifts and their real time and operational use requires caution and specific quality control.

Since the quality control procedures on the real-time oxygen data are limited and automatic and considering that the presence of trend in the deep ocean can be considered a proxy for oxygen sensor drift, a novel operational quality assessment procedure of BGC-Argo oxygen data for model validation and assimilation is here proposed. 

The QC procedure is based on (1) sensor drift computation with the RANSAC (RANdom SAmple Consensus) and Theil-Sen non parametric statistical estimators at two selected depths: 600 and 800m and (2) suspicious drift-oxygen-profiles correction.
Moreover, drift-corrected and uncorrected oxygen profiles are subjected to additional checks: (i) Comparison of surface value with oxygen at saturation (ii) Offset calculation between data and EMODnet2018_int climatological values at 550-650m (iii) Model-data misfit threshold.

The QC criteria have constrained more than one third of oxygen data to be corrected for a suspicious drift. In most cases, the removal of the drift acted as a relaxation factor towards the reference climatological fields.
To test the assimilation of quality-checked oxygen profiles into the CMEMS Mediterranean model system, a set of 2-year OGSTM-BFM-3DVarBio simulations have been implemented. Results show the feasibility of the oxygen data assimilation and the potential much higher impact of oxygen BGC-Argo data with respect to the chlorophyll and nitrate sensors given the evolution of the numbers of BGC-Argo sensors in recent years.

How to cite: Amadio, C., Teruzzi, A., and Cossarini, G.: Integration of BGC-Argo and the Mediterranean BGC forecast system: new developments of the oxygen data quality assessment and assimilation, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5550, https://doi.org/10.5194/egusphere-egu22-5550, 2022.

The Copernicus Marine service (CMEMS) in operation today routinely delivers information about the Green Ocean based on satellite and in situ data combined with numerical models. The aim is to provide users with “best estimate” representations of the state of marine ecosystems and biogeochemical indicators of interest. A key strategic evolution at Copernicus 2 horizon will be to consolidate the service with more robust information about product uncertainties, whether in real time, in delayed mode (reanalyses) and in forecast mode with a few days of lead time. In that perspective, the transition to probabilistic analysis and prediction methodologies is a necessary step, e.g. to provide more actionable information to help in decision-making and management of marine ecosystems.

In the frame of the H2020 SEAMLESS project, ensemble generation methods are being developed with the aim to improve the service through better data assimilation / inversion methods. A stochastic version of the NEMO-PISCES model has been developed and implemented in a global ocean configuration at ¼° inherited from the CMEMS global Monitoring and Forecasting Centre.

A 40-member ensemble is generated using 2019 unperturbed ERA5 atmospheric forcings and assuming uncertainties associated to (i) 7 critical biogeochemical model parameters of the PISCES formulation; (ii) sub-grid scale effects associated to the eddy-permitting resolution, and (iii) misplacement of mesoscale structures and associated advective/diffusive fluxes. The resulting 40-member ensemble represents a probabilistic view of the 2019 seasonal cycle in the global and North Atlantic ocean.

The ensemble is analysed in terms of spread, median, min and max distributions of model state variables related to surface chlorophyll concentration, as well as on a variety of targeted indicators (e.g. NPP, phenology, trophic efficiency). In order to evaluate the relevance of the ensemble pdfs with respect to observed data, verification statistics have been produced to check the consistency against daily L4 ocean colour products from the CMEMS catalogue. The computed metrics include rank histograms, CRPS (decomposed into reliability and resolution skill scores) and RCRV.

We will present a synthesis of the ensemble scores obtained in the different regions, highlighting situations where the prior ensemble is consistent with uncertainty hypotheses made in the stochastic NEMO-PISCES model. Further, we will show how to take into account irreducible uncertainties in the verification data products to compute the scores. We will discuss the sensitivity of the computed metrics against these uncertainties, underlying the importance of properly accounting for error propagation in the CMEMS TAC production chains. We will finally describe first applications of a new 4D Bayesian inversion scheme aimed at delivering probabilistic analyses and predictions with a few days of lead time.

How to cite: Popov, M., Brankart, J.-M., Brasseur, P., Capet, A., and Cosme, E.: Towards probabilistic analyses and predictions of the Green Ocean using a stochastic NEMO-PISCES modelling system, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1489, https://doi.org/10.5194/egusphere-egu22-1489, 2022.

The presentation focuses on two key points in bio-geochemical ensemble based data assimilation: the ensemble generation methods as well as the impact of the data assimilation on various bio-geochemical processes. We conduct the data assimilation experiments from October 2014. These are preparations for a future reanalysis product provided by the Baltic Monitoring and Forecasting Centre (BAL-MFC), which will cover the years 1993 – 2021. The Local Error Subspace Kalman Transform Filter (LESKTF) algorithm in the Parallel Data Assimilation Framework PDAF (http://pdaf.awi.de) is applied for data assimilation of profile data from the SHARK database on a daily basis. After the daily analysis is performed, the mean of the ensemble members is used in the Nemo-ERGOM model system. This method is used operationally by the BAL-MFC.

Effects of the number of ensembles, transformations, generation techniques and deflation of the ensemble are explored and verified in our ensemble generation studies. Rank histograms, skewness and kurtosis of the ensembles before and after assimilation are computed.

The influences of dissolved oxygen profile data assimilation on the nutrients in deep layers are studied and compared with the integral influences of univariate data assimilation of dissolved oxygen, nitrate, phosphate and ammonium on the same variables. Validation results of the univariate data assimilation scheme are presented and discussed in regards to quality enhancement for the future reanalysis product.

How to cite: Düsterhöft-Wriggers, W., Spruch, L., Lindenthal, A., Li, X., Lorkowski, I., and Team, B.: Ensemble based data assimilation of bio-geochemical profile data in the Baltic Sea with a Nemo-ERGOM model system, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9599, https://doi.org/10.5194/egusphere-egu22-9599, 2022.

We introduced feedback from the simulated biogeochemistry to physics in the framework of the CMEMS operational physical-biogeochemical model of the North-West European Shelf. Using this development we demonstrate that light attenuation by the biogeochemical tracers has a significant impact on ocean heating in the upper 200m of the water column. We also show that the simulated temperature is sensitive to the modelling scheme representing the underwater light attenuation, i.e in how it resolves spectra, direction and the optically active tracers. We will discuss in detail the impact of these developments on the research version of the CMEMS operational model that includes assimilation of temperature, salinity and chlorophyll.

How to cite: Skakala, J., Bruggeman, J., Ford, D., and Ciavatta, S.: The impact of marine biogeochemistry on physics and its consequences for the modelling of North-West European shelf seas, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1523, https://doi.org/10.5194/egusphere-egu22-1523, 2022.

Since mid-2019, meso-zooplankton and micronekton reanalyses (large past time series that are processed with time-consistent forcings) are available and regularly extended for the CMEMS catalogue. The product (also known as MICRORYS) is computed using SEAPODYM-LMTL, the Lower and Mid Trophic levels model of the Spatial Ecosystem And POpulation DYnamic Modeling framework. Meso-zooplankton organisms (200µm-2mm) constitute the low-trophic level. These organisms are transported along with the water masses. Micronekton organisms, constituting the mid-trophic level, are bigger organisms (2-20cm) able to swim over short distances. SEAPODYM models the spatial and population t dynamics of the LMTL population with a system of advection-diffusion-reaction equations. The vertical dimension is simplified into three layers (namely epipelagic, upper, and lower mesopelagic). Layers matches the vertical distribution of organisms that is observed. The six micronekton groups are defined according to their diel vertical migration  from the surface at night to the deep ocean during the day. At the moment MICRORYS products use a global configuration of SEAPODYM at 1/12° daily resolution. This product has evolved considerably since the first delivery. We propose here to review the state of the art of this product. Some case studies and the developments that are expected in the near future, especially those concerning a better estimation on high latitudes will be presented.

How to cite: Titaud, O., Conchon, A., and Lehodey, P.: Zooplankton and Micronekton products from the CMEMS Catalogue: state of the current product and development plan, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7961, https://doi.org/10.5194/egusphere-egu22-7961, 2022.

Large aggregations of the copepod Calanus finmarchicus occur each spring in the shelf-slope-oceanic regions off the Lofoten-Vesterålen Islands where productive fisheries have traditionally supported local and global economies. The retention and off-shelf transport of C. finmarchicus populations were studied by analyzing ocean color remote sensing and satellite altimetry data between 2010 and 2019 and employing a Lagrangian Coherent Structures (LCS) model. Results revealed the existence of a transport barrier reoccurring at the shelf break that retains C. finmarchicus on the shelf for 30-70 days in the spring when C. finmarchicus were seasonally ascending to the surface layer. The analysis of baroclinic and barotropic energy conversions indicated that the topographically steered Norwegian Atlantic Current (NwAC) is the primary mechanism in the formation of the transport barrier, which restricts exchanges of C. finmarchicus populations between shelf and oceanic waters. In the mid- or late April, an increase in baroclinicity leads to an increase in mesoscale eddies generated on the shelf break near Lofoten-Vesterålen Islands, breaking down transport barriers and causing off-shelf transport of C. finmarchicus. The transport barrier predictably reoccurs in early spring which supports the entrapment of C. finmarchicus in the shelf region.

How to cite: Dong, H., Zhou, M., Hu, Z., Zhang, Z., Zhong, Y., Basedow, S., and Smith, W.: Transport Barriers and the Retention of Calanus finmarchicus on the Lofoten Shelf in Early Spring , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6005, https://doi.org/10.5194/egusphere-egu22-6005, 2022.

 Advanced data assimilation methods can improve the forecast of Arctic sea ice, which has been widely used in climate modeling systems to merge observations into simulations. We apply the deterministic Ensemble Kalman filter (DEnKF) to a Lagrangian sea ice model, neXtSIM for sea ice forecast. neXtSIM is computationally solved on a time-dependent evolving mesh, causing a key challenge for applying the EnKF since the mesh grid number and positions are generally different in each ensemble member. The DEnKF analysis is performed on a fixed reference mesh, where model variables are interpolated between the reference mesh and the individual ensemble meshes before and after the assimilation. An ensemble-DA forecasting system for Arctic sea ice forecast based on neXtSIM is built by assimilating the OSI-SAF sea ice concentration (SIC) and the CS2SMOS sea ice thickness (SIT). The ensemble is generated by perturbing atmospheric and oceanic forcing online throughout the forecast. We evaluate the impact of sea-ice assimilation on the Arctic winter sea-ice forecast skills against the satellite observations and a free run during the 2019-2020 Arctic winter. Significant improvements in modeled SIT indicate the importance of assimilating CS2SMOS thickness. While the improvement of SIC and ice extend are clearly observed only in the case with daily assimilating OSI-SAF SIC, which avoids the constraint of daily loaded ocean variables. We found that assimilating a special observation gives the best forecast skill of the relevant variables. With a proper assimilation strategy, neXtSIM as a stand-alone sea ice model could perform computationally efficiently and maintain good forecast skills compared with coupled models.

How to cite: Cheng, S., Chen, Y., Aydogdu, A., Bertino, L., Carrassi, A., Rampal, P., and K. R. T. Jones, C.: Improved Arctic sea ice forecasting by combining ensemble Kalman filter with a Lagrangian sea ice model, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1113, https://doi.org/10.5194/egusphere-egu22-1113, 2022.

The neXtSIM-F operational forecast was upgraded in December 2021, with the following developments:

• improvements to the rheology, with the neXtSIM model now running the latest version of the Brittle Bingham-Maxwell rheology (BBM).
    The previous version  was running a preliminary version of the BBM rheology.
• The model domain was extended to include the Labrador Sea, Hudson and Baffin Bay.
• Better tuning of dynamic (eg of basal stress parameters for the fast ice off the coast of the eastern Arctic)  and thermodynamic parameters.

The upgrade resulted in good improvements to the ice thickness and extent, although drift developed a slight slow bias. However the bias is of the order
of the observation error (1-1.25km/day).

Planned developments for the next 3 years include:

• assimilation of ice thickness data
• assimilation of ice extent from NIC ice charts (National Ice Center, USA)  instead of from passive microwave (OSISAF).
• increased resolution, to go from about 7.5km to about 3.75km
• a multi-year reanalysis to be updated every month

How to cite: Williams, T., Korosov, A., Olason, E., and Bertino, L.: Status and prospects for the neXtSIM-F CMEMS operational forecast, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8255, https://doi.org/10.5194/egusphere-egu22-8255, 2022.

The variability of ice-covered area in the Southern Ocean plays a crucial role in the modulating the exchange of heat, mass and momentum between ocean and atmosphere. Knowledge of ice properties and their variability is necessary for an adequate simulation of those fluxes. Global ocean reanalyses provide consistent and comprehensive records of ocean and sea ice variables and are therefore of pivotal significance for climate studies, particularly in data-sparse regions such as Antarctica.

We present the temporal and spatial variability of Antarctic sea ice area in the CMEMS ensemble of global ocean reanalyses (GREP), over the 1993-2019 period. We assess the accuracy of GREP in reproducing the evolution in time and space of Antarctic total sea ice and discriminating between sea ice classes, the marginal ice zone (MIZ) from consolidated pack ice. GREP provides consistent estimates of recent changes in the Antarctic sea ice area and propery reproduces observed interannual and seasonal variability, linear trend, as well as record highs and lows. For sea ice classes, the ensemble spread is comparable to the spread among observational estimates. GREP is shown to properly represent the variability of pack and MIZ areas during the growing and melting seasons, as well as their minima and maxima. More evident discrepancies between GREP and satellite products occur during summer, when the spread among individual ORA increases. Nonetheless, due to minimization of the single errors, the ensemble mean provides the most consistent and reliable estimates. 

Our analysis suggests that GREP can be used to get a robust estimate of current Antarctic sea ice state and recent trends in sea ice area and extent.

How to cite: Iovino, D., Selivanova, J., Masina, S., and Cipollone, A.: Antarctic marginal ice zone in the CMEMS GREP ensemble reanalysis product , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10494, https://doi.org/10.5194/egusphere-egu22-10494, 2022.

Ocean reanalyses reconstruct the ocean state with a long integration of an ocean model constrained by atmospheric surface forcing and observations via data assimilation. Since their results are more accurate in comparison to those derived from a model alone, they are a powerful tool to provide ocean monitoring indicators (OMIs) as well as to better understand the physical properties and dynamics of the Black Sea. In the scope of the Copernicus Marine Service (CMEMS), the Black Sea physical reanalysis (BS-REA) system has been used to support the implementation of new indicators in the Black Sea. The system is built upon the hydrodynamic model NEMO v3.6 at 1/27° x 1/36°, and 31 unevenly distributed vertical levels, coupled to OceanVar for the assimilation of the best available observations (both in situ and satellite ones). In this contribution, we present the current operational indicators for the monitoring of temperature and salinity anomalies. BS-REA system provides temperature trends that indicate a warming of the basin: 0.0829±0.01069 ^oC year^-1, 0.0380±0.0005 ^oC year^-1, 0.0041±0.0001 ^oC year^-1, respectively, in 0-25 m, 25-150 m and 150-300 m. Since 2007, the warming signal has been very clear in such a way that the Black Sea cold intermediate layer (CIL) almost disappeared in recent years. However, this continuous warming is interrupted in 2012 and less explicitly in 2017, years in which a replenishment of the CIL is verified. Similar analyses for salinity reveal that salinity trends reduce in depth and are larger from 2005, especially in surface layers. The system is very suitable for understanding the physical state of the Black Sea in recent years and allows to obtain more accurate OMIs for the sea, which are important to understand its response to climate change. 

Following recent CMEMS Ocean State Report contributions, new OMIs based on the ocean heat content anomaly and freshwater content anomaly will be produced this year, whereas indexes on the basis of the interannual variations of the Black Sea Rim Current intensity, the Black Sea overturning circulation and the coastal upwelling along the Turkish coast will be provided as OMIs in the near future. BS-REA is under continuous update in order that new versions will bring improvements in both the numerical model and data assimilation components.

How to cite: Lima, L., Ilicak, M., Gunduz, M., Causio, S., Peneva, E., Angela Ciliberti, S., Aydoğdu, A., Azevedo, D., Stefanizzi, L., Clementi, E., Coppini, G., Masina, S., and Pinardi, N.: Monitoring the Black Sea climate: recent advancements for building ocean indicators, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8315, https://doi.org/10.5194/egusphere-egu22-8315, 2022.

This study aims to analyse long-term interannual changes in extreme winds and waves in the Black Sea. Severe wave conditions from 1979 to 2020 are detected using the 99th percentile of the significant wave height (SWH), based on the method proposed in (Weisse and Günther, 2007; Staneva et al., 2020a). Long-term spatial wave statistics of the Black Sea are then obtained based on the annual trend of 99th percentile SWH and the number, lifetime, and intensity of extreme events occurring between 1979 and 2020. In addition, the variability of these extreme event characteristics is demonstrated. Besides, wave reanalysis of the Black Sea is used to investigate intraannual variation and long-term wave energy potential change. Hence, wave power and wind statistics are shown for Black Sea CMEMS multiyear products to identify the most suitable areas for wave energy exploitation and offshore wind power potential and to determine the safe and efficient design, installation and operation of marine energy sector assets. The results reveal that the average number of storm events is the highest in the eastern basin. In contrast, the average lifetime reaches a maximum on the southwestern coast. Intensity peaks in the same region as the lifetime but is also high in the basin interior. Spatial mean extreme event analyses show a slight increase in event numbers and intensity, but decreasing trends for the event lifetime and maximum area of storm events. In regions where wave conditions are strong, there have been increases in extremes relative to normal conditions in recent years. This can significantly affect designs. In terms of wave energy, mean wave power peaks in the southwestern area of the Black Sea. The wave power trend follows a pattern similar to that of the SWH with a pronounced east–west difference; its variation is higher, resulting in a coefficient of variation (CoV) of ~2.5.

How to cite: Staneva, J., Ricker, M., Akpinar, A., Behrens, A., Giesen, R., and von Schuckmann, K.: Long-term interannual changes in extreme winds and waves in the Black Sea, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6629, https://doi.org/10.5194/egusphere-egu22-6629, 2022.

A marine heatwave (MHW) is defined as a prolonged period (usually 5 days or more) of sea-surface temperature (SST) above the 90th climatological percentile, which is potentially devastating for marine ecosystems and economy. The available ocean information by Copernicus Marine (CMEMS) and Climate (C3S) Services allows the real-time detection and seasonal prediction of MHW. Reported 2020 MHW events in the North East Pacific happen in the context of increased frequency of long heatwaves. A positive feedback loop by which atmospheric conditions impact the upper ocean stratification making the ocean mixed layer more responsive to anomalous surface fluxes has been identified in reanalyses. The increased stratification at the base of the mixed layer seen since 2017 coincides with the resurgence of MHWs from 2018 onwards. Reliable predictions of developing MHW conditions could help advance planning and preparedness for such extreme variability events in the ocean. Seasonal forecasts showed skill in predicting the 2020 events at seasonal timescales, especially once the ocean was preconditioned after the first MHW of that year. The first order assessment of the forecast skill for MHW predictions presented here showed encouraging results, but for such information to be actionable in the future there is need to gain more confidence on the quality of the seasonal forecast information. Statistical forecast reliability quantification and further process understanding will be the subject of a follow-up study.

How to cite: de Boisseson, E., Balmaseda, M., Mayer, M., and Zuo, H.: Monitoring and predictions of Marine Heatwave events in the North East Pacific from ocean reanalyses and seasonal forecasts, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4079, https://doi.org/10.5194/egusphere-egu22-4079, 2022.

Monitoring and assessment in the Baltic Sea region have been coordinated by HELCOM (Helsinki Commission) since 1979, with the first periodic assessment published in 1986. HELCOM latest assessments are based on indicators that reflect the achievement or non-achievement of good environmental status (GES) in the sub-basins of the Baltic Sea. For this purpose, HELCOM has developed a set of core indicators, with each of them having a quantitative GES threshold.

This comprehensive indicator-based system requires long-term and systematic measurements to minimize the influence of natural (spatial and temporal) variability on the trend estimates. State indicators and background hydrographic characteristics (as drivers of natural variability) have to be calculated and evaluated to distinguish pressure-induced changes/trends. However, routine environmental monitoring is carried out with a low spatial and temporal resolution. While model data could be used as a substitute, they are not applied yet largely due to shortcomings in accuracy and overall mistrust of model products.

We assessed the possibility of using the model and remote sensing data provided by Copernicus Marine Environment Monitoring Service (CMEMS) to calculate HELCOM eutrophication indicators and influencing hydrographic characteristics or extreme events like marine heatwaves and coastal upwelling events. Reanalysis products BALTICSEA_REANALYSIS_BIO_003_012 and BALTICSEA_REANALYSIS_PHY_003_011 together with remote sensing product SST_BAL_SST_L4_REP_OBSERVATIONS_010_016 were used for state indicators and hydrographic characteristics, respectively.

Selected HELCOM eutrophication indicators were calculated following HELCOM methodology as average concentrations in the surface layer (0 – 10 m) for winter (DIN and DIP), summer (Chl-a) and whole year (TN and TP). Indicator calculations show a steady decline in concentrations of all nutrient compounds in recent years for all basins in the north-eastern Baltic Sea that is not confirmed by the measurements. We suggest a way forward for harvesting monitoring data prior to their official submission deadline and producing interim reanalysis products to improve the confidence of assessments based on CMEMS products.

For occurrence and intensity of heatwaves, a climatology (1986-2020) of sea surface temperature (SST) and the 90^th percentile was calculated for each grid cell in the Baltic Sea. The heatwave was identified when SST exceeded the 90^th percentile value for a site and date. For upwellings, the SST data were analyzed along transects from coast to coast in either North-South or East-West direction. Every grid point with the local SST value >2 °C colder than the transect average was assigned to a coastal upwelling event. The results based on two selected products (reanalysis and remote sensing) agree well except in years/seasons when the seasonal thermocline was very shallow (e.g. 2018). We demonstrate that CMEMS products covering the surface layer dynamics in the Baltic Sea (e.g. SST) can be used in describing long-term trends and inter-annual variability in hydrographic conditions (also extreme events) and serve as background information for indicator-based eutrophication assessments.

How to cite: Samlas, O., Stoicescu, S.-T., She, J., and Lips, U.: Potential of CMEMS products for assessing eutrophication status and natural variability in the north-eastern Baltic Sea., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11280, https://doi.org/10.5194/egusphere-egu22-11280, 2022.

This study examines sea level change in the context of decadal-scale variability in the ocean-atmosphere dynamics of the tropical Atlantic. This time scale is of great significance for adaptation and mitigation in the context of increasing societal threats from the ongoing harmful effects of anthropogenic climate change. Decadal climate variability in the Atlantic is caused by the interaction of the gyres and is evidenced by persistent multi-year anomalies in sea surface temperature, heat content and thermocline depth (through steric sea level and dynamic height). In this study, the tropical sea level anomaly (SLA) was decomposed into interannual and decadal time scales via an empirical orthogonal function (EOF) method. The SLA variability was investigated and found to be closely related to climatic variability patterns. In addition, decadal SLA variabilities were observed between 1993 and 2016, with SLA and SLP seasonal shifts occurring in the second decade, with no change in the equatorial wind stress, responsible for warm events.

How to cite: Kemgang Ghomsi, F. E., Pappukutty Raj, R., and Rouault, M.: Decadal Sea Level Variability in the Tropical Atlantic, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6607, https://doi.org/10.5194/egusphere-egu22-6607, 2022.

Deep convection in the Subpolar Gyre (SPG) of the North Atlantic forms a link between the upper and lower limbs of the Atlantic Meridional Overturning Circulation (AMOC). The intensity of convection is estimated using mixed layer depth (MLD) derived from in situ vertical profiles of potential density. Given limited areas of convective chimneys, the robustness of the estimates from an available set of vertical profiles needs to be verified before studying mechanisms of interannual variability of convection intensity. For reaching this goal, we first computed the frequency of deep convection events observed in situ and split the convective regions into three domains: the central part of the Irminger Sea (I-DC), the southwestern part of the Labrador Sea (L-DC), and a domain south of Cape Farewell (F-DC). For each domain, we identified two types of development of the convective regions using k-means cluster analysis. Then, for each convection domain and each convection type, the minimum number of randomly scattered casts required for a robust estimate of the maximum MLD during the convective period are derived as a criterion of a robust estimate of the convection intensity. The results showed that, for all the convection domains, a sufficient number of casts during a cold season was collected since the late 1990s for some years, while uninterrupted time series are obtained since the mid-2000s. The main modes of spatio-temporal variability of salinity and temperature in the upper North Atlantic, preceding the years with high/low convection intensity, are accessed through constructing the composite maps of their anomalies and the empirical orthogonal function (EOF) analysis. The first EOF of temperature closely corresponds to the composite map of temperature anomalies, while its principal component has a high correlation with interannual variability of convection in the I-DC and F-DC convection domains, and a moderate one in the L-DC domain. At the same time, a high correlation with the SPG index is also observed. The results suggest that the variability of these dynamic patterns may play an important role in shaping convection intensity in the SPG.

Funding: The research was funded by Saint Petersburg State University (SPSU), project no. 75295423.

How to cite: Fedorov, A. M., Bashmachnikov, I. L., Iakovleva, D. A., Kuznetcova, D. A., and Raj, R. P.: Deep convection in the Subpolar Gyre, how much data is needed to estimate its intensity?, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3396, https://doi.org/10.5194/egusphere-egu22-3396, 2022.

A fleet of more than 50.000 cargo ships worldwide has an enormous demand for energy resulting in considerable emissions. According to the 4th International Maritime Organization (IMO) global greenhouse gas (GHG) study, maritime transport emitted around 1,056 million tonnes of CO₂ in 2018 and was responsible for about 2.9% of the global anthropogenic CO₂ emissions. While the emissions per tonne and nautical mile have been reduced by almost 30% in the last decade, the overall emissions of cargo ships increased by more than 10% (up to 30% in some models) due to the growing demand. In order to tackle this increase, the MariData project conducts research on how an improved hydrodynamical modeling and the use of detailed predictions and data of sea state and environmental conditions can reduce the energy demand and hence emissions of cargo ships. 

In this set-up, a cloud-based geo data platform takes on a central role, which combines different data sets from CMEMS, GFS, recorded ship trajectories and further data sources. The geo platform acts as a data broker and provider as well as a machine learning environment for data mining and route predictions. One of its use cases is a data driven machine learning approach where freely available records of AIS data are combined with sea state and weather information and serve as a training set for a random forest regression. This model is capable of predicting the expected speed of cargo ships (characterized by width, length and draught) based on the sea state and weather forecasts. Due to the lack of detailed data on fuel consumption or energy demand, we need to exploit a heuristic. Under the assumption of a constant engine load for free sailing areas, the achieved speed depends on the resistance due to environmental conditions. Pixels with a low resistance are then favored for an energy optimized route. The geo platform also collects and provides data that is used by partners of the research project in their own routing application or to enhance and test their hydrodynamical analysis. 

We will present the technical set-up combining the data sources and facilitating the subsequent data mining and data analysis. Preliminary results of models and optimized routes will be presented. Finally, limitations of the approach and the data availability will be discussed.

How to cite: Pontius, M., Zaabalawi, S., Jürrens, E. H., and Gräler, B.: Reducing cargo ship emissions through energy demand optimized routing, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9927, https://doi.org/10.5194/egusphere-egu22-9927, 2022.

The mesoscale variability in the Mediterranean Sea is investigated through eddy detection techniques. The analysis is performed over 24 years (1993–2016) considering the three-dimensional (3D) fields from an ocean re-analysis of the Mediterranean Sea (MED-REA). The objective is to achieve a fit-for-purpose assessment of the 3D mesoscale eddy field. In particular, we focus on the contribution of eddy-driven anomalies to ocean dynamics and thermodynamics. The accuracy of the method used to disclose the 3D eddy contributions is assessed against pointwise in-situ measurements and observation-based data sets. Eddy lifetimes ≥ 2 weeks are representative of the 3D mesoscale field in the basin, showing a high probability (> 60%) of occurrence in the areas of the main quasi-stationary mesoscale features. The results show a dependence of the eddy size and thickness on polarity and lifetime: anticyclonic eddies (ACE) are significantly deeper than cyclonic eddies (CE), and their size tends to increase in long-lived structures which also show a seasonal variability. Mesoscale eddies result to be a significant contribution to the ocean dynamics in the Mediterranean Sea, as they account for a large portion of the sea-surface height variability at temporal scales longer than 1 month and for the kinetic energy (50–60%) both at the surface and at depth. Looking at the contributions to ocean thermodynamics, the results exhibit the existence of typical warm (cold) cores associated with ACEs (CEs) with exceptions in the Levantine basin (e.g., Shikmona gyre) where a structure close to a mode-water ACE eddy persists with a positive salinity anomaly. In this area, eddy-induced temperature anomalies can be affected by a strong summer stratification in the surface water, displaying an opposite sign of the anomaly whether looking at the surface or at depth. The results show also that temperature anomalies driven by long-lived eddies (≥ 4 weeks) can affect up to 15–25% of the monthly variability of the upper ocean heat content in the Mediterranean basin.

How to cite: Bonaduce, A., Cipollone, A., Johannessen, J. A., Staneva, J., Raj, R. P., and Aydogdu, A.: Ocean Mesoscale Variability: A Case Study on the Mediterranean Sea From a Re-Analysis Perspective, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5325, https://doi.org/10.5194/egusphere-egu22-5325, 2022.

Eddy kinetic energy (EKE) is a measure of temporal and spatial variability of ocean mesoscale eddies . This study elucidates the key factors that determine the spatial distribution and seasonality of mesoscale eddies of the south-eastern Arabian sea (SEAS) using satellite observational data from Copernicus Marine service data centre, during the time period 1993-2016. In general eddy kinetic energy is found to higher during winter. The higher EKE throughout the winter were found to be due to the barotropic instability of the Winter Monsoon Current . This is owing to current’s barotropic instability due to wind stress curl, resulting in the conversion of mean kinetic energy to eddy kinetic energy. The ESA OC-CCI data were used to study the influence of EKE on the primary productivity using linear regression and correlation analysis. A significant positive correlation between EKE and chlorophyll-a concentration during winter monsoon indicates the impact of EKE on the distribution of surface chlorophyll-a concentration over the SEAS during winter monsoon.  

How to cite: Mohan Pillai, U., Joseph Kochuparampil, A., Pappukutty Raj, R., and Mathias Johannessen, O.: Seasonal variability of eddy kinetic energy in southeastern Arabian Sea, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7396, https://doi.org/10.5194/egusphere-egu22-7396, 2022.

The South Kuril region belongs to the Northwestern part of the Pacific Ocean and is characterized by a complex system of interactions between two large currents: the Kuroshio, which carries warmer waters from the southwest, and the Oyashio, which carries colder waters from the northeast. As a result of the currents’ interaction, the frontal zones arise; they are characterized by active vortex formation. The cyclonic and anticyclonic eddies may occur due to the separation of meanders from the Kuroshio current or can be formed in the process of collision of eddies already existing in this system. Dynamic parameters and thermohaline structure of eddies affect the fishing of saury and squid in the area of the southern Kuril Islands.

In this work, dynamic parameters and thermohaline structure of certain eddies based on data from daily reanalysis GLORYS12V1 are analyzed. The GLORYS12V1 product is the CMEMS global ocean eddy-resolving reanalysis. It covers the altimetry from 1993 to 2019, has a horizontal resolution of 1/12° and 50 vertical levels. It is based on the current real-time global forecasting CMEMS system. The model component is the NEMO driven at the surface by ECMWF ERA-Interim. Observations are assimilated using a reduced-order Kalman filter. Along track altimeter data (Sea Level Anomaly), Satellite Sea Surface Temperature, Sea Ice Concentration and In situ Temperature and Salinity vertical Profiles are jointly assimilated. In this work, the data «GLOBAL_REANALYSIS_PHY_001_030» available at https://resources.marine.copernicus.eu/product-detail/GLOBAL_MULTIYEAR_PHY_001_030 is used.

This work aims to study the dynamic parameters and thermohaline structure of several eddies formed in the South Kuril region. We detect and monitor the eddies and investigate hydrological conditions in them favorable for fishing.

How to cite: Lebedeva, M. and Belonenko, T.: Thermohaline structure and dynamic parameters of mesoscale eddies of South Kuril region, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2257, https://doi.org/10.5194/egusphere-egu22-2257, 2022.

Aleutian eddies are mesoscale anticyclonic eddies formed within the Alaskan Stream over the
Aleutian trench in the area of 50-52 ° N, 170-175 ° E. It is found that canyons along the shelf
fault appear to be more prone to eddy activity than regions without canyons. Aleutian eddies
propagate southwestward after the separation from the Alaskan Stream and pass through the
Western Subarctic Gyre, carrying the transformed waters of the Gulf of Alaska to the western
part of the Pacific Subarctic. Fishermen and oceanographers are well aware of the role of
some anticyclonic eddies near the trenches in the formation of places favorable for fishing.
They are formed by the mixing of the waters of the Alaskan Stream and the waters of the
Subarctic Current. The appearance of Aleutian eddies is accompanied by a deepening of
isopycnic surfaces and an increase in temperature and concentration of dissolved oxygen in
the layer of 150– 400 m.
Based on the GLORYS12V1 data, the thermohaline structure of individual eddies and their
dynamic properties are analyzed. The GLORYS12V1 product is a global reanalysis covering
altimetry data since 1993. It is based on the existing real-time CMEMS (Copernicus Marine
Environment Monitoring Service) global forecasting system. The component of this model is
the NEMO platform controlled on the surface by ECMWF ERA-Interim. The observations
are then assimilated using a reduced-order Kalman filter. The work uses daily data for 2019
"GLOBAL_REANALYSIS_PHY_001_030" displayed on a standard regular grid in 1/12°
increments (approximately 8 km) and on 50 standard levels.

How to cite: Khudyakova, S. and Belonenko, T.: Trench Aleutian anticyclonic eddies: generation and evolution, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12532, https://doi.org/10.5194/egusphere-egu22-12532, 2022.