European High Frequency Radar network governance

This report describes the governance of the European HF radar network including: the landscape of the Ocean observation networks and infrastructures, the role and links between operators of observational systems and stakeholders, the role and activities of the EuroGOOS HF radar Task Team in building a sound community strategy, the roadmap of the community with current achievements and future work lines

Study of the surface ocean dynamics in the Bay os Biscay, using HF radar technology

RESUMEN: El primer paso de esta tesis doctoral, ha sido evaluar las capacidades de sistema vasco de radar de alta frecuencia y su potencial para el cálculo operacional de trayectorias en el mar. En segundo lugar, se han aplicado con éxito diferentes metodologías de análisis de datos (EOF, KMA) para extraer los patrones de circulación superficial y estudiar las diferentes escalas espacio-temporales. Los resultados muestran la continuidad de la corriente a lo largo de la plataforma/talud en la esquina SE del Golfo de Bizkaia, con orientación este-oeste (norte-sur) frente a la costa española (francesa), con una marcada estacionalidad, de acuerdo a las observaciones anteriores de diversos autores. La mayoría de los patrones de circulación superficial observados están claramente relacionados con patrones específicos de viento, recurrentes en el área. Sin embargo, existe una gran variabilidad en términos interacción de patrones espaciales de circulación superficial y patrones de viento. Se han identificado varios patrones de circulación no tan claramente relacionadas con las condiciones de viento específicas.ABSTRACT: The first step of this PhD Thesis, has been to assess the performances of the Basque High Frequency (HF) radar system and its potential for operational calculation of trajectories at sea. Secondly, different methodologies have successfully been applied to HF radar data (e.g. EOF, KMA) to extract surface current patterns and to study the different spatio-temporal scales. The results reveal the continuity of the along shelf/slope surface circulation in the SE corner of the Bay of Biscay, with east-west (north-south) surface circulation in front of the Spanish (French) coast, with a marked seasonality, in accordance to the previous observations. Most of the surface current patterns observed are clearly related to specific wind patterns, recurrent in the study area. However, there is high variability in terms of surface current spatial patterns and of wind–current interactions. Several current patterns not as clearly related with specific wind conditions have also been identified

Surface water circulation patterns in the southeastern bay of biscay: new evidences from hf radar data

High Frequency (HF) radar stations have been working operationally in the southeastern part of the Bay of Biscay since 2009. The (2) systems provide hourly surface currents, with 5 km spatial resolution and a radial coverage lying close to 180 km. The detailed and quantitative description of the spatial patterns observed by the HF radar offers new evidence on the main ocean processes, at different time scales, affecting a study area where surface currents show marked temporal and spatial variability. A clear seasonality in terms of sea surface currents and along-slope circulation is observed, with cyclonic and anticyclonic patterns during the winter and summer months, respectively. From the analysis of low-pass filtered currents, a key component of this seasonal variability is associated with the surface signature of the slope current (Iberian Poleward Current (IPC)). Clearly intensified over the upper part of the slope, this current circulates eastward off the Spanish coast and northward over the French shelves in winter. Examination of the HF radar current fields reveals the presence of mesoscale structures over the area. At higher frequencies, an EOF (Empirical Orthogonal Function) analysis of the inertial band-pass filtered data is used to study the complex spatial and temporal patterns associated with these processes and to evaluate quantitatively the relative contribution of the high frequency to the total variability, in space and time. Overall, inertial currents represent between 10 and 40% of the total variability; their contribution is significantly greater in summer and over the deeper part of the slope. Tides contribute much less than the total Kinetic Energy (KE), although their contribution over the shelf can be higher than that of the inertial oscillations, during winter

HF-Radar Tools

This report provides a description of the different tools developed for tackling key issues of the High Frequency Radar (HFR) community: advanced delayed time QC of HFR historical data, implementation of Best Practices, enhancing the application of HFR observations in NRT modelling assessment and Ocean State indicator

Skill Assessment of HF Radar-Derived Products for Lagrangian Simulations in the Bay of Biscay

Since January 2009, two long-range high-frequency (HF) radar systems have been collecting hourly high-spatial-resolution surface current data in the southeastern corner of the Bay of Biscay. The temporal resolution of the HF radar surface currents permits simulating drifter trajectories with the same time step as that of real drifters deployed in the region in 2009. The main goal of this work is to compare real drifter trajectories with trajectories computed from HF radar currents obtained using different methods, including forecast currents. Open-boundary modal analysis (OMA) is applied to the radar radial velocities and then a linear autoregressive model on the empirical orthogonal function (EOF) decomposition of an historical data series is used to forecast OMA currents. Additionally, the accuracy of the forecast method in terms of the spatial and temporal distribution of the Lagrangian distances between observations and forecasts is investigated for a 4-yr period (2009-12). The skills of the different HF radar products are evaluated within a 48-h window. The mean distances between real trajectories and their radar-derived counterparts range from 4 to 5 km for real-time and forecast currents after 12 hours of simulations. The forecast model improves persistence (i.e., the simulations obtained by using the last available OMA fields as a constant variable) after 6 hours of simulation and improves the estimation of trajectories up to 28% after 48 hours. The performance of the forecast is observed to be variable in space and time, related to the different ocean processes governing the local ocean circulation

A new Lagrangian-based short-term prediction methodology for high-frequency (HF) radar currents

The use of high-frequency radar (HFR) data is increasing worldwide for different applications in the field of operational oceanography and data assimilation, as it provides real-time coastal surface currents at high temporal and spatial resolution. In this work, a Lagrangian-based, empirical, real-time, short-term prediction (L-STP) system is presented in order to provide short-term forecasts of up to 48 h of ocean currents. The method is based on finding historical analogs of Lagrangian trajectories obtained from HFR surface currents. Then, assuming that the present state will follow the same temporal evolution as the historical analog, we perform the forecast. The method is applied to two HFR systems covering two areas with different dynamical characteristics: the southeast Bay of Biscay and the central Red Sea. A comparison of the L-STP methodology with predictions based on persistence and reference fields is performed in order to quantify the error introduced by this approach. Furthermore, a sensitivity analysis has been conducted to determine the limit of applicability of the methodology regarding the temporal horizon of Lagrangian prediction. A real-time skill score has been developed using the results of this analysis, which allows for the identification of periods when the short-term prediction performance is more likely to be low, and persistence can be used as a better predictor for the future currents.This research has been supported by EU Horizon 2020 (grant nos. LIFE15 ENV/ES/000252, 654410, and 871153) and by the Spanish MINECO (grant no. 256 RTI2018-093941-B-C31 co-financed with FEDER funds)

JERICO-S3 D.5.5 - WP5 - Report on the functional homogenization tools that will support the implementation of best practices within the JERICO-RI. Version 1.0.

This document describes a series of functional tools available for the JERICO-RI community supporting the harmonized management of mature coastal observing platforms as described in JERICO-S3 D5.2, namely Mooring, FerryBox, High Frequency Radar, Underwater Glider. They include tools entirely designed and realized within JERICO-S3 and tools that have received a substantial contribution from JERICO-S3 discussions, deliverables, workshops, and have been developed in a collaborative framework with other projects. Tools span from software routines for data management and data Quality Control to web applications for joint management of platform issues to methods and guidelines for structuring practices documentation and assessing their maturity level. After the introduction, a main section contains the descriptions of each tool according to a uniform scheme. First, a table is provided summarizing key information like the tool’s purpose, scope of applicability, the link to the tool itself and to its documentation. Then, the tool and its features are described with a minimum level of detail. A second paragraph highlights the added value and contribution deriving from actual and/or previous work in JERICO projects, aimed at supporting the tool development. The contribution could be in terms of best practices, deliverables, workshops, surveys, etc. The last paragraph is dedicated to the foreseen and potential use of the tool in a wider context and/or as a component or framework for other tools

Observing Networks final Assessment

This deliverable presents the Final Assessment of the observation and thematic networks as those represented in work package 3 of EuroSea, taking as a reference the information on Deliverable 3.2 Observing Network Initial Assessment. Following the same approach with D3.2 the original questionnaire was modified accordingly in order to depict the progress made on the same Network Attributes, Commitments and Benefits following the GOOS, OCG guidelines. The unforeseen COVID-19 pandemic had significant effects upon WP3 activities since the main mechanism foreseen to advance progress within the different networks was the organization of in person workshops. Moreover, adequate funds were allocated towards this in order to promote inclusivity and participation. Adapting to the new situation the first series of workshops had to be changed into online only events which despite the inherent difficulty, proved to have significant advantages as well. In particular they gave the opportunity for a significant number of people to join from all around the globe and participate in the events (for example the Sea Level WS). Another challenge proved to be the variability within some networks with sub-components or sub-groups having significantly different characteristics. In particular Eulerian platforms comprise a wide range of platforms - fixed moorings, surface buoys, cable bottom platforms - with some of them being part of mature and well-developed networks (OceanSITES, EMSO etc) while other are loose partners of on-going programs and projects (JERICO RI, coastal buoys). EuroSea activities had a significant positive impact on all the observing and thematic networks, actively promoting synergies and collaboration, with most of them successfully reaching Framework Processes Readiness Criteria Level 7 and above. Although progress at many different aspects must continue beyond EuroSea, it is important that the framework has been set. It is thus suggested that an annual evaluation/assessment process for each network/task team is adopted within EuroGOOS. By going through this exercise annually, each EuroGOOS Task Team (observing network) will be able to describe its current state, assess progress and most importantly to define next targets and priorities