Evaluating high-frequency radar data assimilation impact in coastal ocean operational modelling

The impact of the assimilation of HFR (high-frequency radar) observations in a high-resolution regional model is evaluated, focusing on the improvement of the mesoscale dynamics. The study area is the Ibiza Channel, located in the western Mediterranean Sea. The resulting fields are tested against trajectories from 13 drifters. Six different assimilation experiments are compared to a control run (no assimilation). The experiments consist of assimilating (i) sea surface temperature, sea level anomaly, and Argo profiles (generic observation dataset); the generic observation dataset plus (ii) HFR total velocities and (iii) HFR radial velocities. Moreover, for each dataset, two different initialization methods are assessed: (a) restarting directly from the analysis after the assimilation or (b) using an intermediate initialization step applying a strong nudging towards the analysis fields. The experiments assimilating generic observations plus HFR total velocities with the direct restart provide the best results, reducing by 53 % the average separation distance between drifters and virtual particles after the first 48 h of simulation in comparison to the control run. When using the nudging initialization step, the best results are found when assimilating HFR radial velocities with a reduction of the mean separation distance by around 48 %. Results show that the integration of HFR observations in the data assimilation system enhances the prediction of surface currents inside the area covered by both antennas, while not degrading the correction achieved thanks to the assimilation of generic data sources beyond it. The assimilation of radial observations benefits from the smoothing effect associated with the application of the intermediate nudging step.

Coupling Rivers and Estuaries with an Ocean Model: An Improved Methodology

Freshwater sources are essential inputs for regional ocean models covering coastal areas such as the western Iberian Peninsula. The problem is how to include the mixture between fresh and salt water, typically performed by estuaries and in the adjacent areas of river mouths, without unsustainable increases of computational time and human setup errors. This work provides a proof-of-concept solution to both these problems through the use of an offline two-way methodology, where local schematic rivers and estuaries are responsible for mixing river freshwater with salt water of a regional model application. Two different offline upscaling methodologies—which focus on the implementation of tidal fluxes from local domains to regional domains in the context of operational modelling—are implemented in the Portuguese Coast Operational Modelling System (PCOMS) regional model application as well as in a version without rivers. A comparison between results produced by these methodologies, field data, and satellite imagery was performed, which confirmed that the proposed methodology of using schematic rivers and estuaries, combined with the new offline upscaling methodology proposed herein, represents a good solution for operational modelling of coastal areas subject to a high dominance of freshwater inputs.

Marine Litter on the Coast of the Algarve: Main Sources and Distribution Using a Modeling Approach

The accumulation of floating marine litter poses a serious threat to the global environment and the economy all over the world, particularly of coastal municipalities that rely on tourism and recreational activities. Data of marine litter is thus crucial, but is usually limited, and can be complemented with modelling results. In this study, the operational modelling system of Algarve (SOMA) was combined with a Lagrangian particle-tracking model and blended with scarce litter monitoring data, to provide first insights into the distribution and accumulation of floating marine litter on the Algarve coast. Different meteo-oceanographic conditions, sources regions and wind drift behaviors were considered. Field data and model results show a considerable concentration of marine litter along the beaches and coastal regions. The model also suggests that oceanographic conditions and wind drift have a great influence on the transport and accumulation rate of the floating marine litter on the coast, with the highest rates of accumulation during the winter and the counter current period, concentrated mostly on the south-western coast of the Algarve.

Local simulations of snow redistribution by wind with an intermediate-complexity snow cover model driven by different wind downscaling methods

<p>In mountainous terrain, wind-driven transport of deposited snow affects the overall distribution of snow, and can have a significant effect on snowmelt patterns even at coarser resolution.  In an operational modelling perspective, a compromise must be found to represent this complex small-scale process with enough accuracy while mitigating the computational costs of snow cover simulations over large domains. To achieve this compromise, we implemented the SNOWTRAN-3D snow transport module within the FSM intermediate complexity snow cover model. We included a new layering scheme and a historical variable of past snow wetting, but without resolving the snow microstructure. Simulations are run and evaluated over a small mountain range in the Swiss Alps at 25 to 100 m resolution. Being implemented in the model framework of the SLF operational snow hydrology service (OSHD), simulations further benefit from snow data assimilation techniques to provide improved estimates of solid precipitation fields. As complex wind patterns in mountains are the key processes driving snow transport, we tested statistical and dynamical methods to downscale 1 km resolution COSMO winds to better reflect topographically-induced flow patterns. These simulations are a first step working towards the integration of wind transport processes over large domains in an intermediate-complexity and -resolution operational modelling framework.</p>

Performance of the Adriatic early warning system during the multi-meteotsunami event of 11–19 May 2020: an assessment using energy banners

This study quantifies the performance of the Croatian meteotsunami early warning system (CMeEWS) composed of a network of air pressure and sea level observations, a high-resolution atmosphere-ocean modelling suite and a stochastic surrogate model. The CMeEWS, which is not operational due to a lack of numerical resources, is used retroactively to reproduce the multiple events observed in the eastern Adriatic between the 11th and 19th of May 2020. It is found that deterministic simulations largely fail to forecast these extreme events at endangered locations along the Croatian cost mostly due to a systematic northwestward shift of the atmospheric disturbances. Additionally, the use of combined ocean and atmospheric model results, instead of atmospheric model results only, is not found to improve the selection of the transects used to extract the atmospheric parameters feeding the stochastic meteotsunami surrogate model. Finally, in operational mode, the stochastic surrogate model would have triggered the warnings for most of the observed events, but also setting off some false alarms. Due to the uncertainties associated with operational modelling of meteotsunamigenic disturbances, the stochastic approach has thus proven to overcome the failures of the deterministic forecasts and should be further developed.

Aim, activities and early outcomes of the Coastal Working Group of the European Global Ocean Observing System (EuroGOOS)

<p>The major interface between humans and the ocean occurs in the coastal seas. Marine industries thrive in this area while European citizens make daily use of the coastal ocean for tourism, leisure and recreation. Operational oceanography assists both industry and the general public to make decisions about their use of and access to the coastal ocean. The EuroGOOS community has developed, based on in-situ and satellite observations, data and modelling capacities, a wide range of products and services for such use cases. <br>The EuroGOOS Coastal working group examines the entire value chain from coastal observations, satellite data, ocean forecasts and analysis, to products and services for coastal users. The working group reviews sustainability and fitness for purpose of the existing system and identifies gaps and future steps needed to secure and improve all elements of the coastal value chain. The EuroGOOS Coastal Working Group builds upon significant initiatives already completed or underway that have focused on coastal observatories. These include, but are not limited to, the work of EMODnet, SeaDataNet, CLMS, and CMEMS-In Situ Thematic Centres (INS TACs), which play significant role in making available key datasets for coastal areas, the JERICO-NEXT and JERICO-S3 EC projects, which work towards sustaining the JERICO-RI on long term, as well as activities within EuroGOOS working groups, platforms task teams, and the five regional operational oceanographic systems (ROOS). <br>More specifically, the main activities of the EuroGOOS Coastal Working Group are: (i) mapping primary users of coastal products, (ii) reviewing available and potential coastal data sources with special focus on river discharges, (iii) preparing a comprehensive inventory of European operational models, (iv) reviewing coastal data assimilation frameworks for optimizing coastal sea monitoring and forecasting systems, (v) preparing an inventory of integrated coastal products and services, and (vi) formulating a EuroGOOS roadmap for the enhanced integration of coastal services into a EuroGOOS Coastal Working Group White Paper. <br>The outcomes of the EuroGOOS Coastal Working Group activities are primarily designed to support four specific areas of the EuroGOOS Strategic Agenda 2020 and the short-term priority areas, namely (1) sustained fit for purpose observations, (2) data matters, (3) product development and (4) communication and outreach. On the other hand, in broader sense these activities contribute to the coastal community through peer reviewed articles such as the review of operational modelling capacity in European Seas (Capet et al., submitted) and by promoting collaboration to initiate new opportunities to effectively serve the coastal users in the industry (e.g. aquaculture sector) as in the H2020 FORCOAST project (www.forcoast.eu). </p>

Exercising war: How tactical and operational modelling shape and reify military practice

This article analyzes how contemporary military training and exercises shape and reify specific modalities of war. Historically, military training has shifted from being individual- and experience-oriented, towards becoming modelled into exercise environments and practices. Drawing on semi-structured interviews with military officers, exercise controllers, and war-game designers, the article distinguishes between tactical training, characterized by military functions embodied through weapon platforms in a demarcated battlespace, and operational training, characterized by administrative and organizational processes embodied through self-referential staff routines. As military exercises integrate the tactical and operational dimensions into a model for warfare, they serve as blueprints for today’s battles at the same time as they perpetuate a martial viewpoint of the world. As a result, preparations for potential future conflicts constitute a fertile ground for apprehending the becoming of war.