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Evan Mason
,
Ananda Pascual
, and
James C. McWilliams
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Evan Mason
,
Ananda Pascual
, and
James C. McWilliams

Abstract

This paper presents a software tool that enables the identification and automated tracking of oceanic eddies observed with satellite altimetry in user-specified regions throughout the global ocean. As input, the code requires sequential maps of sea level anomalies such as those provided by Archiving, Validation, and Interpretation of Satellite Oceanographic (AVISO) data. Outputs take the form of (i) data files containing eddy properties, including position, radius, amplitude, and azimuthal (geostrophic) speed; and (ii) sequential image maps showing sea surface height maps with active eddy centers and tracks overlaid. The results given are from a demonstration in the Canary Basin region of the northeast Atlantic and are comparable with a published global eddy track database. Some discrepancies between the two datasets include eddy radius magnitude, and the distributions of eddy births and deaths. The discrepancies may be related to differences in the eddy identification methods, and also possibly to differences in the smoothing of the sea surface height maps. The code is written in Python and is made freely available under a GNU license (http://www.imedea.uib.es/users/emason/py-eddy-tracker/).

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Esther Capó
,
Alejandro Orfila
,
Evan Mason
, and
Simón Ruiz

Abstract

Energy conversion routes are investigated in the western Mediterranean Sea from the eddy–mean flow interactions. The sources of eddy kinetic energy are analyzed by applying a regional formulation of the Lorenz energy cycle to 18 years of numerical simulation at eddy-resolving resolution (3.5 km), which allows for identifying whether the energy exchange between the mean and eddy flow is local or nonlocal. The patterns of energy conversion between the mean and eddy kinetic and potential energy are estimated in three subregions of the domain: the Alboran Sea, the Algerian Basin, and the northern basin. The spatial characterization of the energy routes hints at the physical mechanisms involved in maintaining the balance, suggesting that flow–topography interaction is strongly linked to eddy growth in most of the domain.

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Esther Capó
,
James C. McWilliams
,
Evan Mason
, and
Alejandro Orfila

Abstract

We present a phenomenological description and dynamical analysis of the Alboran fronts using a realistic simulation at submesoscale resolution. The study is focused on east Alboran fronts emerging within relatively strong flows that separate from the Spanish coast into the basin interior. Despite modest lateral shifting associated with the position of the Alboran anticyclonic gyres and variations in intensity, these fronts present a similar structure and dynamical configuration as the climatological Almeria–Oran front. The statistical analysis of our solution shows that strained-induced frontogenesis is a recurrent submesoscale mechanism associated with these fronts, and the process is assessed in terms of the advective Lagrangian frontogenetic tendencies associated with buoyancy and velocity horizontal gradients. Intermittency in their strength and patterns is indicative of high variability in the occurrence of active frontogenesis in association with the secondary (overturning) circulation across the frontal gradient. As a result, we find many episodes with strong surface fronts that do not have much associated downwelling. Frontogenesis and the associated secondary circulation are further explored during two particular frontal events, both showing strong downwelling of O (1) cm s−1 extending down into the pycnocline. A frontogenetic contribution of turbulent vertical momentum mixing to the secondary circulation is identified in the easternmost region during the cold season, when the dynamics are strongly influenced by the intrusion of the salty Northern Current. The background vertical velocity fields observed during the analyzed events indicate other currents in the submesoscale range, including tidal and topographic internal waves.

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Chunxue Yang
,
Chiara Cagnazzo
,
Vincenzo Artale
,
Bruno Buongiorno Nardelli
,
Carlo Buontempo
,
Jacopo Busatto
,
Luca Caporaso
,
Claudia Cesarini
,
Irene Cionni
,
John Coll
,
Bas Crezee
,
Paolo Cristofanelli
,
Vincenzo de Toma
,
Yassmin Hesham Essa
,
Veronika Eyring
,
Federico Fierli
,
Luke Grant
,
Birgit Hassler
,
Martin Hirschi
,
Philippe Huybrechts
,
Eva Le Merle
,
Francesca Elisa Leonelli
,
Xia Lin
,
Fabio Madonna
,
Evan Mason
,
François Massonnet
,
Marta Marcos
,
Salvatore Marullo
,
Benjamin Müller
,
Andre Obregon
,
Emanuele Organelli
,
Artur Palacz
,
Ananda Pascual
,
Andrea Pisano
,
Davide Putero
,
Arun Rana
,
Antonio Sánchez-Román
,
Sonia I. Seneviratne
,
Federico Serva
,
Andrea Storto
,
Wim Thiery
,
Peter Throne
,
Lander Van Tricht
,
Yoni Verhaegen
,
Gianluca Volpe
, and
Rosalia Santoleri

Abstract

If climate services are to lead to effective use of climate information in decision-making to enable the transition to a climate-smart, climate-ready world, then the question of trust in the products and services is of paramount importance. The Copernicus Climate Change Service (C3S) has been actively grappling with how to build such trust: provision of demonstrably independent assessments of the quality of products, which was deemed an important element in such trust-building processes. C3S provides access to essential climate variables (ECVs) from multiple sources to a broad set of users ranging from scientists to private companies and decision-makers. Here we outline the approach ­undertaken to coherently assess the quality of a suite of observation- and reanalysis-based ECV products covering the atmosphere, ocean, land, and cryosphere. The assessment is based on four pillars: basic data checks, maturity of the datasets, fitness for purpose (scientific use cases and climate studies), and guidance to users. It is undertaken independently by scientific experts and presented alongside the datasets in a fully traceable, replicable, and transparent manner. The methodology deployed is detailed, and example assessments are given. These independent scientific quality assessments are intended to guide users to ensure they use tools and datasets that are fit for purpose to answer their specific needs rather than simply use the first product they alight on. This is the first such effort to develop and apply an assessment framework consistently to all ECVs. Lessons learned and future perspectives are outlined to potentially improve future assessment activities and thus climate services.

Open access