Computation of a new Mean Dynamic Topography for the Mediterranean Sea from model outputs, altimeter measurements and oceanographic in-situ data

The accurate knowledge of the ocean Mean Dynamic Topography (MDT) is a crucial issue for a number of oceanographic applications and in some areas of the Mediterranean Sea, important limitations have been found pointing to the need of an upgrade. We present a new Mean Dynamic Topography (MDT) that was computed for the Mediterranean Sea. It takes profit of improvements made possible by the use of extended datasets and refined processing. The updated dataset spans the 1993–2012 period and consists of: drifter velocities, altimetry data, hydrological profiles and model data. The methodology is similar to the previous MDT Rio et al. (2007). However, in Rio et al. (2007) no hydrological profiles had been taken into account. This has required the development of dedicated processing. A number of sensitivity studies have been carried out to obtain the most accurate MDT as possible. The main results from these sensitivity studies are the following: moderate impact to the choice of correlation scales but almost negligible sensitivity to the choice of the first guess (model solution). A systematic external validation to independent data has been made to evaluate the performance of the new MDT. Compared to previous version, SMDT-MED-2014 features shorter scales structures, which results in an altimeter velocity variance closer to the observed velocity variance and, at the same time, gives better Taylor skills.The SMDT-MED-2014 was produced in the framework of a contract funded by SOCIBPeer Reviewe

Multi-platform experiments, numerical simulations and data science techniques for generation of new altimetric products: focus on mesoscale and sub- mesoscale variability (MANATEE – OSTST proposal)

Trabajo presentado en la Ocean Surface Topography Science Team Meeting (OSTST), celebrada online del 19 al 23 de octubre de 2020

Cruise Plan: Fine-Scale ocean currents from integrated multi-platform experiments and numerical simulations: contribution to the new SWOT satellite mission (FaSt-SWOT, PID2021-122417NB-I00)

The FaSt-SWOT project is funded by the Spanish Research Agency and the European Regional Development Fund (AEI/FEDER, UE) under Grant Agreement (PID2021-122417NB-I00). The present research is conducted within the framework of the activities of the Spanish Government through the "María de Maeztu Centre of Excellence'' accreditation to IMEDEA (CSIC-UIB) (CEX2021-001198). The Spanish Ministry of Science and Innovation, the Regional Government of the Balearic Islands and the Spanish Research Council (CSIC) are acknowledged for their support to the ICTS SOCIB. A. P., B. M. and B. B. L. thank the European Union funding through the EuroSea project an Horizon 2020 research and innovation programme under grant agreement No 862626.With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2021-001198).Peer reviewe

Altimetry for the future: Building on 25 years of progress

In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the ‘‘Green” Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instruments’ development and satellite missions’ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion

Altimetry for the future: building on 25 years of progress

In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the “Green” Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instruments’ development and satellite missions’ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion

Quasi-geostrophic vertical motion from satellite and in-situ observations: Impact on South East Pacific nitrate distribution through a Lagrangian simulation

The objective of this study is to improve our understanding of the influence of mesoscale vertical exchanges on ecosystem dynamics. In particular, we aim to investigate the influence of vertical velocity on ocean tracer distributions in the South East Pacific. Previous remote sensing studies in this region have revealed that chlorophyll distributions within mesoscale eddies are characterised by dipole-like patterns, with extreme values found at the eddy peripheries. An observation-based product, ARMOR3D, is used to obtain an estimate of 3D currents. Horizontal velocities are derived from application of the geostrophic equations to 3D fields of temperature and salinity obtained from the ARMOR3D reanalysis that combines satellite (SST and altimetry) and in-situ (Argo profiling floats, XBTs, CTDs and moorings) data. Vertical velocities are estimated from quasi-geostrophic (QG) dynamics by integrating the QG Omega equation with ARMOR3D fields. Finally, a Lagrangian particle tracking model, forced by the derived 3D currents, is used to study passive tracer dispersion and its influence on the distribution of biochemical properties such as nitrates. The Lagrangian results show that the impact of vertical advection on nitrate distribution is non-negligible as they account for about 30% of the contribution of horizontal advection.Peer Reviewe

Impact of vertical and horizontal advection on nutrient distribution in the South East Pacific

An innovative approach is used to analyse the impact of vertical velocities associated with quasi-geostrophic (QG) dynamics on the distribution of a passive nutrient tracer (nitrate) in the South East Pacific. Twelve years of vertical and horizontal currents are derived from an observation-based estimate of the ocean state. Horizontal velocities are obtained through application of thermal wind balance to weekly temperature and salinity fields. Vertical velocities are estimated by integration of the QG Omega equation. Seasonal variability of the synthetic vertical velocity and kinetic energy associated with the horizontal currents are coincident, with peaks in austral summer (November–December) in accord with published observations. Two ensembles of Lagrangian particle tracking experiments that differ according to vertical forcing (w = wQG vs. w = 0) enable a quantitative analysis of the impact of the vertical velocity. From identical initial distributions of nitrate-tagged particles, the Lagrangian results show that the impact of vertical advection on nutrient distribution is 30 % of the contribution of horizontal advection. Despite being weaker by a factor of up to 10−4 than the horizontal currents, vertical velocity is demonstrated to make an important contribution to nutrient distributions in the region of studyThis work has been carried out as part of E-MOTION (CTM2012-31014) project funded by the Spanish National Research Program. Additional funding from the Local Government of the Balearic Islands (CAIB-51/2011 grant) is also acknowledged. Bàrbara Barceló-Llull is supported by a pre-doctoral grant from the Spanish National Research Program associated to the PUMP (CTM2012-33355) project. Evan Mason is supported by a post-doctoral grant from the Conselleria d’Educació, Cultura i Universitats del Govern de les Illes Balears (Mallorca, Spain) and the European Social FundPeer Reviewe

Dataset to accompany "Lagrangian reconstruction to extract small-scale salinity variability from SMAP observations"

- Oleander_reconstructions: each netcdf file in this folder corresponds to the simulation done to reconstruct sea surface salinity SMAP observations for each day having in situ observations from the M/V Oleander thermosalinograph. - Weekly_reconstructions: each netcdf file in this folder corresponds to the simulation done to reconstruct weekly sea surface salinity SMAP observations. Note that the period between 2019-06-19 and 2019-07-22, when SMAP sea surface salinity data were not produced, is excluded.-- In each netcdf file: The dimension “traj” refers to the identifier for each simulated particle. The dimension “obs” refers to each time step. To plot maps of the reconstructed salinity fields, plot the particles at their final position with their salinity value. This is: lon(all indices, last index). lat(all indices, last index), sss_adv(all indices). The date in each netcdf file name is the date of the final position, i.e., the date of the reconstructed field.Lagrangian reconstruction of gridded sea surface salinity (SSS) observations made by the Soil Moisture Active Passive (SMAP) satellite in the northwest Atlantic Ocean. Using altimetric geostrophic currents, we numerically advected SMAP SSS fields to produce a Lagrangian reconstruction that represents small scales. For more details of the Lagrangian reconstruction method, see the associated paper “Lagrangian reconstruction to extract small-scale salinity variability from SMAP observations” available at https://doi.org/10.1029/2020JC016477. In this paper we compare the reconstructed fields with in situ observations from the M/V Oleander thermosalinograph and we evaluate the small-scale SSS variability of the northwest Atlantic Ocean.This dataset has been developed in the framework of the (Sub)mesoscale Salinity Variability at Fronts project (NNX17AK04G) funded by the National Aeronautics and Space Administration (NASA).Peer reviewe

Finescale ocean currents in the Med Sea. Summary and advances in inversion activities at IMEDEA

Trabajo presentado al SWOT Inversion Working Group Meeting, celebrado on-line el 13 de octubre de 2021.Peer reviewe

Applications of mesoscale dynamics: Impacts of vertical motion on nitrate distribution

Trabajo presentado en la EGU General Assemby 2013, celebrada del 7 al 12 de abril de 2013 en Viena (Austria)Peer Reviewe