North Atlantic extratropical and subpolar gyre variability during the last 120 years: a gridded dataset of surface temperature, salinity, and density. Part 1: dataset validation and RMS variability

We present a binned annual product (BINS) of sea surface temperature (SST), sea surface salinity (SSS), and sea surface density (SSD) observations for 1896–2015 of the subpolar North Atlantic between 40° N and 70° N, mostly excluding the shelf areas. The product of bin averages over spatial scales on the order of 200 to 500 km, reproducing most of the interannual variability in different time series covering at least the last three decades or of the along-track ship monitoring. Comparisons with other SSS and SST gridded products available since 1950 suggest that BINS captures the large decadal to multidecadal variability. Comparison with the HadSST3 SST product since 1896 also indicates that the decadal and multidecadal variability is usually well-reproduced, with small differences in long-term trends or in areas with marginal data coverage in either of the two products. Outside of the Labrador Sea and Greenland margins, interannual variability is rather similar in different seasons. Variability at periods longer than 15 years is a large part of the total interannual variability, both for SST and SSS, except possibly in the south-western part of the domain. Variability in SST and SSS increases towards the west, with the contribution of salinity variability to density dominating that of temperature in the western Atlantic, except close to the Gulf Stream and North Atlantic Current in the southwest area. Weaker variability and larger relative temperature contributions to density changes are found in the eastern part of the gyre and south of Iceland

The Copernicus Marine Environment Monitoring Service Ocean State Report

The Copernicus Marine Environment Monitoring Service (CMEMS) Ocean State Report (OSR) provides an annual report of the state of the global ocean and European regional seas for policy and decision-makers with the additional aim of increasing general public awareness about the status of, and changes in, the marine environment. The CMEMS OSR draws on expert analysis and provides a 3-D view (through reanalysis systems), a view from above (through remote-sensing data) and a direct view of the interior (through in situ measurements) of the global ocean and the European regional seas. The report is based on the unique CMEMS monitoring capabilities of the blue (hydrography, currents), white (sea ice) and green (e.g. Chlorophyll) marine environment. This first issue of the CMEMS OSR provides guidance on Essential Variables, large-scale changes and specific events related to the physical ocean state over the period 1993–2015. Principal findings of this first CMEMS OSR show a significant increase in global and regional sea levels, thermosteric expansion, ocean heat content, sea surface temperature and Antarctic sea ice extent and conversely a decrease in Arctic sea ice extent during the 1993–2015 period. During the year 2015 exceptionally strong large-scale changes were monitored such as, for example, a strong El Niño Southern Oscillation, a high frequency of extreme storms and sea level events in specific regions in addition to areas of high sea level and harmful algae blooms. At the same time, some areas in the Arctic Ocean experienced exceptionally low sea ice extent and temperatures below average were observed in the North Atlantic Ocean

Steric sea level variability (1993-2010) in an ensemble of ocean reanalyses and objective analyses

Quantifying the effect of the seawater density changes on sea level variability is of crucial importance for climate change studies, as the sea level cumulative rise can be regarded as both an important climate change indicator and a possible danger for human activities in coastal areas. In this work, as part of the Ocean Reanalysis Intercomparison Project, the global and regional steric sea level changes are estimated and compared from an ensemble of 16 ocean reanalyses and 4 objective analyses. These estimates are initially compared with a satellite-derived (altimetry minus gravimetry) dataset for a short period (2003–2010). The ensemble mean exhibits a significant high correlation at both global and regional scale, and the ensemble of ocean reanalyses outperforms that of objective analyses, in particular in the Southern Ocean. The reanalysis ensemble mean thus represents a valuable tool for further analyses, although large uncertainties remain for the inter-annual trends. Within the extended intercomparison period that spans the altimetry era (1993–2010), we find that the ensemble of reanalyses and objective analyses are in good agreement, and both detect a trend of the global steric sea level of 1.0 and 1.1 ± 0.05 mm/year, respectively. However, the spread among the products of the halosteric component trend exceeds the mean trend itself, questioning the reliability of its estimate. This is related to the scarcity of salinity observations before the Argo era. Furthermore, the impact of deep ocean layers is non-negligible on the steric sea level variability (22 and 12 % for the layers below 700 and 1500 m of depth, respectively), although the small deep ocean trends are not significant with respect to the products spread

PRODUCT USER MANUAL. For Global Delayed Mode Insitu Dataset. INSITU_GLO_TS_REP_OBSERVATIONS_013_001_b called CORA

CORA-GLOBAL-5.1 is a situ global temperature and salinity dataset that aggregates data from Coriolis database which is the IN SITU TAC Global component of the WP15 of CMEMS project. This dataset is updated once a year by R&D Coriolis team and data are extracted in NetCDF Argo format at a given date. The dataset contains data from different types of instruments: mainly Argo floats, XBT, CTD and XCTD, and Moorings. The data are stored in different files types: PF, XB, CT, OC, MO, BA, TE ... explained hereafter in the manual. Measurements from CORA have been through both Coriolis validation (automatic checks, objective analysis) and a delayed-mode validation (format and range checks, climatological tests, spike checks, duplicates checks, XBT correction, ultimate objective analysis). This Product User Manual describes CORA-GLOBAL-5.1 dataset called INSITU_GLO_TS_REP_OBSERVATIONS_013_001_b in CMEMS catalogue: how is it built, what is the content, which data services are available to have access to the data. The Easy CORA dataset in an extraction of the CORA-GLOBAL dataset providing only the best quality measurements with a vertical and temporal sub setting

Quality Information Document. In Situ TAC INSITU_GLO_PHY_TS_DISCRETE_MY_013_001. And Synthesis Quality Overview document (SQO)

INSITU_GLO_PHY_TS_DISCRETE_MY_013_001 or CORA (Coriolis Ocean Dataset for Reanalysis), also called “Global Ocean-Full CORA- in situ Observations Yearly Delivery in Delayed Mode” is a global dataset of ocean in situ sea temperature and salinity (T/S) measurements. This document aims to give a detailed picture of the processes and tools used to validate this dataset. The INSITU_GLO_PHY_TS_DISCRETE_MY_013_001 product is made up of 2 different datasets: - The CORA dataset including the full profiles and full metadata covering the global ocean, with distinct data distribution for the In-Situ TAC regions (including global ocean and the European regions). - A dataset derived from CORA, the Easy CORA dataset, with a simplified data structure and format

Product User Manual. In Situ TAC objective analysis Products. INSITU_GLO_PHY_TS_OA_MY_013_052 and INSITU_GLO_PHY_TS_OA_NRT_013_002

Products INSITU_GLO_PHY_TS_OA_MY_013_052 and INSITU_GLO_PHY_TS_OA_NRT_013_002 generated by the Coriolis team (the Data Centre and the Research & Development team) in Brest, France, provide global Temperature and Salinity observations datasets and objective analysis gridded fields at different time scales. The second one is a Near Real Time product (NRT) while the first one (also called CORA Analysed fields, see Cabanes et al., 2013 and Szekely et al., 2019) is a reanalysis of these Near Real Time datasets in delayed-mode. This Product User Manual describes the multiyear INSITU_GLO_PHY_TS_OA_MY_013_052 and the near real time INSITU_GLO_PHY_TS_OA_NRT_013_002 products from the Copernicus In Situ Thematic Centre: how they are built, which content, which data services are available to access them.

Dynamique et variabilité du front d'Ouessant, approche observationnelle

The understanding of the dynamics and variability the Iroise sea current in a key issue for the naval security on the western part of the English Channel. The Ushant tidal front is a central element of the Iroise sea, which separates the coastal homogeneous waters from the seasonally homogenized waters located offshore. This thesis is based on numerous measurements made during the FROMVAR 2009, 2010 and 2011 cruises, and studies the dynamics and the variability of the Ushant front.First, the temperature and salinity measurements collected during the FROMVAR cruises are analyzed in order to observe the water masses surrounding the Ushant front. Observations covering the whole continental shelf are studied first, using data collected during the FROMVAR 2010 and 2011 cruises. A second study focused on the water masses which makes the Ushant front in the Iroise sea.Then, the surface currents observed by HF radars are analyzed in order to study the dynamics related to the low frequency residual currents in the Iroise sea. The influence of the wave induced Stokes drift on surface currents is first studied in order to avoid the influence of wave on the observed currents.The dynamics of the observed surface currents is then discussed thanks to the comparison of winter and summer measurements, for various tidal ranges. The vertical shear measured by an ADCP close to the front is finally compared to the vertical shear corresponding to the geostrophic adjustment of the front.Last, kinetic energy dissipation rate measurements collected during the FROMVAR 2009 cruise are exposed to study the fortnightly variability of turbulent mixing. A study of the variability of modeled currents during the fortnightly cycle is then performed in order to discuss the influence of ageostrophic cross-front currents on the fortnightly displacement of the bottom front.La compréhension de la dynamique et la variabilité des courants en mer d’Iroise est en enjeu majeur pour l’exploitation du rail maritime d’Ouessant. Celle-ci passe par une analyse du développement du front saisonnier d’Ouessant, qui sépare les eaux homogènes situées le long de la côte des eaux stratifiées au large. Cette thèse se base sur les nombreuses mesures récoltées pendant les campagnes FROMVAR successives et porte particulièrement sur l’étude de la dynamique et de la variabilité de front de température. Tout d’abord, une partie des mesures de température et de salinité réalisées pendant les campagnes FROMVAR 2009, 2010 et 2011 sont analysées afin de comprendre le contexte hydrologique dans lequel se place le front d’Ouessant. Dans un premier temps, une comparaison entre les observations à l’échelle du plateau continental réalisées en 2010 et 2011 est menée. Un travail similaire porte ensuite sur les masses d’eau formant le front d’Ouessant, observées en 2009 et 2010.Une seconde étude a pour but d’identifier la dynamique des courants basse fréquence observés par les radars HF, en mer d’Iroise. Le jeu de données de 4 ans d’observations radar est traité afin de réduire au maximum les effets des vagues et du vent sur les courants observé, et les observations correspondant aux périodes hivernales et estivales sont comparées. La comparaison de courants mesurés par des ADCP avec les courants géostrophiques attendus dans l’hypothèse d’un ajustement du front permet ensuite de discuter de la dynamique de celui-ci.Enfin, des mesures de dissipation de l’énergie cinétique turbulente réalisées pendant la campagne FROMVAR 2009 permettent d’étudier la variation du mélange pendant le cycle de vives-eaux/mortes-eaux. Une étude de la variabilité des courants basses fréquences calculés dans cette zone par un modèle réaliste permet d’étudier le lien entre les courants résiduels de marée et la position du front pendant le cycle de vives-eaux/mortes-eaux

Dynamics and variability of the Ushant tidal front from observations

La compréhension de la dynamique et la variabilité des courants en mer d’Iroise est en enjeu majeur pour l’exploitation du rail maritime d’Ouessant. Celle-ci passe par une analyse du développement du front saisonnier d’Ouessant, qui sépare les eaux homogènes situées le long de la côte des eaux stratifiées au large. Cette thèse se base sur les nombreuses mesures récoltées pendant les campagnes FROMVAR successives et porte particulièrement sur l’étude de la dynamique et de la variabilité de front de température. Tout d’abord, une partie des mesures de température et de salinité réalisées pendant les campagnes FROMVAR 2009, 2010 et 2011 sont analysées afin de comprendre le contexte hydrologique dans lequel se place le front d’Ouessant. Dans un premier temps, une comparaison entre les observations à l’échelle du plateau continental réalisées en 2010 et 2011 est menée. Un travail similaire porte ensuite sur les masses d’eau formant le front d’Ouessant, observées en 2009 et 2010.Une seconde étude a pour but d’identifier la dynamique des courants basse fréquence observés par les radars HF, en mer d’Iroise. Le jeu de données de 4 ans d’observations radar est traité afin de réduire au maximum les effets des vagues et du vent sur les courants observé, et les observations correspondant aux périodes hivernales et estivales sont comparées. La comparaison de courants mesurés par des ADCP avec les courants géostrophiques attendus dans l’hypothèse d’un ajustement du front permet ensuite de discuter de la dynamique de celui-ci.Enfin, des mesures de dissipation de l’énergie cinétique turbulente réalisées pendant la campagne FROMVAR 2009 permettent d’étudier la variation du mélange pendant le cycle de vives-eaux/mortes-eaux. Une étude de la variabilité des courants basses fréquences calculés dans cette zone par un modèle réaliste permet d’étudier le lien entre les courants résiduels de marée et la position du front pendant le cycle de vives-eaux/mortes-eaux.The understanding of the dynamics and variability the Iroise sea current in a key issue for the naval security on the western part of the English Channel. The Ushant tidal front is a central element of the Iroise sea, which separates the coastal homogeneous waters from the seasonally homogenized waters located offshore. This thesis is based on numerous measurements made during the FROMVAR 2009, 2010 and 2011 cruises, and studies the dynamics and the variability of the Ushant front.First, the temperature and salinity measurements collected during the FROMVAR cruises are analyzed in order to observe the water masses surrounding the Ushant front. Observations covering the whole continental shelf are studied first, using data collected during the FROMVAR 2010 and 2011 cruises. A second study focused on the water masses which makes the Ushant front in the Iroise sea.Then, the surface currents observed by HF radars are analyzed in order to study the dynamics related to the low frequency residual currents in the Iroise sea. The influence of the wave induced Stokes drift on surface currents is first studied in order to avoid the influence of wave on the observed currents.The dynamics of the observed surface currents is then discussed thanks to the comparison of winter and summer measurements, for various tidal ranges. The vertical shear measured by an ADCP close to the front is finally compared to the vertical shear corresponding to the geostrophic adjustment of the front.Last, kinetic energy dissipation rate measurements collected during the FROMVAR 2009 cruise are exposed to study the fortnightly variability of turbulent mixing. A study of the variability of modeled currents during the fortnightly cycle is then performed in order to discuss the influence of ageostrophic cross-front currents on the fortnightly displacement of the bottom front

Dynamique et variabilité du front d'Ouessant, approche observationnelle

The understanding of the dynamics and variability the Iroise sea current in a key issue for the naval security on the western part of the English Channel. The Ushant tidal front is a central element of the Iroise sea, which separates the coastal homogeneous waters from the seasonally homogenized waters located offshore. This thesis is based on numerous measurements made during the FROMVAR 2009, 2010 and 2011 cruises, and studies the dynamics and the variability of the Ushant front.First, the temperature and salinity measurements collected during the FROMVAR cruises are analyzed in order to observe the water masses surrounding the Ushant front. Observations covering the whole continental shelf are studied first, using data collected during the FROMVAR 2010 and 2011 cruises. A second study focused on the water masses which makes the Ushant front in the Iroise sea.Then, the surface currents observed by HF radars are analyzed in order to study the dynamics related to the low frequency residual currents in the Iroise sea. The influence of the wave induced Stokes drift on surface currents is first studied in order to avoid the influence of wave on the observed currents.The dynamics of the observed surface currents is then discussed thanks to the comparison of winter and summer measurements, for various tidal ranges. The vertical shear measured by an ADCP close to the front is finally compared to the vertical shear corresponding to the geostrophic adjustment of the front.Last, kinetic energy dissipation rate measurements collected during the FROMVAR 2009 cruise are exposed to study the fortnightly variability of turbulent mixing. A study of the variability of modeled currents during the fortnightly cycle is then performed in order to discuss the influence of ageostrophic cross-front currents on the fortnightly displacement of the bottom front.La compréhension de la dynamique et la variabilité des courants en mer d’Iroise est en enjeu majeur pour l’exploitation du rail maritime d’Ouessant. Celle-ci passe par une analyse du développement du front saisonnier d’Ouessant, qui sépare les eaux homogènes situées le long de la côte des eaux stratifiées au large. Cette thèse se base sur les nombreuses mesures récoltées pendant les campagnes FROMVAR successives et porte particulièrement sur l’étude de la dynamique et de la variabilité de front de température. Tout d’abord, une partie des mesures de température et de salinité réalisées pendant les campagnes FROMVAR 2009, 2010 et 2011 sont analysées afin de comprendre le contexte hydrologique dans lequel se place le front d’Ouessant. Dans un premier temps, une comparaison entre les observations à l’échelle du plateau continental réalisées en 2010 et 2011 est menée. Un travail similaire porte ensuite sur les masses d’eau formant le front d’Ouessant, observées en 2009 et 2010.Une seconde étude a pour but d’identifier la dynamique des courants basse fréquence observés par les radars HF, en mer d’Iroise. Le jeu de données de 4 ans d’observations radar est traité afin de réduire au maximum les effets des vagues et du vent sur les courants observé, et les observations correspondant aux périodes hivernales et estivales sont comparées. La comparaison de courants mesurés par des ADCP avec les courants géostrophiques attendus dans l’hypothèse d’un ajustement du front permet ensuite de discuter de la dynamique de celui-ci.Enfin, des mesures de dissipation de l’énergie cinétique turbulente réalisées pendant la campagne FROMVAR 2009 permettent d’étudier la variation du mélange pendant le cycle de vives-eaux/mortes-eaux. Une étude de la variabilité des courants basses fréquences calculés dans cette zone par un modèle réaliste permet d’étudier le lien entre les courants résiduels de marée et la position du front pendant le cycle de vives-eaux/mortes-eaux

Dynamique et variabilité du front d'Ouessant, approche observationnelle

The understanding of the dynamics and variability the Iroise sea current in a key issue for the naval security on the western part of the English Channel. The Ushant tidal front is a central element of the Iroise sea, which separates the coastal homogeneous waters from the seasonally homogenized waters located offshore. This thesis is based on numerous measurements made during the FROMVAR 2009, 2010 and 2011 cruises, and studies the dynamics and the variability of the Ushant front.First, the temperature and salinity measurements collected during the FROMVAR cruises are analyzed in order to observe the water masses surrounding the Ushant front. Observations covering the whole continental shelf are studied first, using data collected during the FROMVAR 2010 and 2011 cruises. A second study focused on the water masses which makes the Ushant front in the Iroise sea.Then, the surface currents observed by HF radars are analyzed in order to study the dynamics related to the low frequency residual currents in the Iroise sea. The influence of the wave induced Stokes drift on surface currents is first studied in order to avoid the influence of wave on the observed currents.The dynamics of the observed surface currents is then discussed thanks to the comparison of winter and summer measurements, for various tidal ranges. The vertical shear measured by an ADCP close to the front is finally compared to the vertical shear corresponding to the geostrophic adjustment of the front.Last, kinetic energy dissipation rate measurements collected during the FROMVAR 2009 cruise are exposed to study the fortnightly variability of turbulent mixing. A study of the variability of modeled currents during the fortnightly cycle is then performed in order to discuss the influence of ageostrophic cross-front currents on the fortnightly displacement of the bottom front.La compréhension de la dynamique et la variabilité des courants en mer d’Iroise est en enjeu majeur pour l’exploitation du rail maritime d’Ouessant. Celle-ci passe par une analyse du développement du front saisonnier d’Ouessant, qui sépare les eaux homogènes situées le long de la côte des eaux stratifiées au large. Cette thèse se base sur les nombreuses mesures récoltées pendant les campagnes FROMVAR successives et porte particulièrement sur l’étude de la dynamique et de la variabilité de front de température. Tout d’abord, une partie des mesures de température et de salinité réalisées pendant les campagnes FROMVAR 2009, 2010 et 2011 sont analysées afin de comprendre le contexte hydrologique dans lequel se place le front d’Ouessant. Dans un premier temps, une comparaison entre les observations à l’échelle du plateau continental réalisées en 2010 et 2011 est menée. Un travail similaire porte ensuite sur les masses d’eau formant le front d’Ouessant, observées en 2009 et 2010.Une seconde étude a pour but d’identifier la dynamique des courants basse fréquence observés par les radars HF, en mer d’Iroise. Le jeu de données de 4 ans d’observations radar est traité afin de réduire au maximum les effets des vagues et du vent sur les courants observé, et les observations correspondant aux périodes hivernales et estivales sont comparées. La comparaison de courants mesurés par des ADCP avec les courants géostrophiques attendus dans l’hypothèse d’un ajustement du front permet ensuite de discuter de la dynamique de celui-ci.Enfin, des mesures de dissipation de l’énergie cinétique turbulente réalisées pendant la campagne FROMVAR 2009 permettent d’étudier la variation du mélange pendant le cycle de vives-eaux/mortes-eaux. Une étude de la variabilité des courants basses fréquences calculés dans cette zone par un modèle réaliste permet d’étudier le lien entre les courants résiduels de marée et la position du front pendant le cycle de vives-eaux/mortes-eaux