Nicolas Kolodziejczyk

Université de Bretagne Occidentale | UBO

Recent estimates of the global inventory of dissolved oxygen (DO) have suggested a decrease of 2 % since the 1960s. However, due to the sparse historical oxygen data coverage, the DO inventory exhibits large regional uncertainties over the interannual timescale. Using the In Situ Analysis System for O2 (ISASO2), a new Argo DO-based optimally interp...

Over the past two decades, Argo profiles have provided unprecedented insight into the global patterns of space and time variability of ocean temperature and salinity, significantly reducing associated uncertainties. However, analyzing such assessments during the pre-Argo period remains challenging due to the scarcity of observations in many regions...

Earth’s energy imbalance (EEI) is a fundamental metric of global Earth system change, quantifying the cumulative impact of natural and anthropogenic radiative forcings and feedback. To date, the most precise measurements of EEI change are obtained through radiometric observations at the top of the atmosphere (TOA), while the quantification of EEI a...

CES Report on Ocean Climate (IROC) combines decades of ocean observations across the North Atlantic ICES regions to describe the current status of sea temperature, salinity, and atmospheric conditions, as well as observed trends and recent variability. Regional analyses are prepared by the local experts who are directly involved in the monitoring p...

Observations of deep Argo displacements (located between 950 and 1150 dbar) and their associated integrated Lagrangian velocities allow for the first time to compute worldwide deep horizontal transfers of Kinetic Energy (KE) between the 3°×3°-Mean and the Eddy reservoirs (MKE and EKE, respectively). This diagnostic reveals that the transfers are ma...

Recent estimates of the global inventory of dissolved oxygen (DO) have suggested a decrease of 2 % since the 1960s. However, due to the sparse historical oxygen data coverage, the DO inventory exhibits large regional uncertainties at interannual timescale. Using ISASO2, a new DO Argo-based optimally interpolated climatology https://doi.org/10.17882...

Quantification of oxygen uptake at the ocean surface and its surface‐to‐interior pathways is crucial for understanding oxygen concentration change in a warming ocean. We investigate the mean meridional global oxygen transport between 1950 and 2009 using coupled physical‐biogeochemical model output. We introduce a streamfunction in latitude‐oxygen c...

In the western tropical Atlantic Ocean close to the Amazon plume, a large loss rate of Argo-float profiles took place, that is, instances of profiles that should have happened but were not transmitted. We find that APEX and SOLO floats were not ascending to the surface in the presence of low surface practical salinity, typically on the order of 32....

The Jan Mayen Channel is located North of the Jan Mayen Island in the Nordic Seas, and is an important gateway for the exchanges of volume, heat and freshwater between the Greenland and the Norwegian basins via the Jan Mayen Current. Based on observations from moored instruments deployed on the shelf and the continental slope of the Jan Mayen Islan...

Plain Language Summary The Greenland Sea is a key region for the climate system. There, during winter, the ocean loses heat to the atmosphere in a process called “deep convection,” that results in the formation of dense water masses that ventilate and fill the deeper layers of the ocean. The Greenland Sea exhibits a high variability in the intensit...

The monitoring of soil moisture and sea surface salinity over the Earth has been profoundly enhanced during the last thirteen years due to a new generation of satellite sensors. L-band radiometry is currently the only technology providing direct measurements of soil moisture, insensitive to surface roughness and distribution of elements in the soil...

The processes driving the seasonal variability of the mixed layer salinity in the Arctic Ocean are investigated using a simulation performed with regional ocean – sea ice model at high resolution. While the seasonal variations of the mixed layer depth remain small, in particular under the perennial sea ice (O(30m)), the mean salinity of the mixed l...

The Earth climate system is out of energy balance, and heat has accumulated continuously over the past decades, warming the ocean, the land, the cryosphere, and the atmosphere. According to the Sixth Assessment Report by Working Group I of the Intergovernmental Panel on Climate Change, this planetary warming over multiple decades is human-driven an...

We investigate the Chukchi and the Beaufort seas in the Arctic Ocean, where salty and warm Pacific Water flows in through the Bering Strait and interacts with the sea ice, contributing to its summer melt. Thanks to in situ measurements recorded by two saildrones deployed during summer 2019 and to refined sea ice filtering in satellite L‐band radiom...

Accurate monitoring of the long-term trend of oxygen content at global scale requires a better knowledge of the regional oxygen variability at interannual to decadal time scale. Here, we combined the Argo dataset and repeated ship-based sections to investigate the drivers of the oxygen variability in the North Atlantic Ocean, a key region for the o...

The ICES Report on Ocean Climate (IROC) combines decades of ocean observations across the North Atlantic ICES regions to describe the current status of sea temperature, salinity, and atmospheric conditions, as well as observed trends and recent variability. The IROC production focuses the main efforts from ICES Working Group on Oceanic Hydrograph

The Earth climate system is out of energy balance and heat has accumulated continuously over the past decades, warming the ocean, the land, the cryosphere and the atmosphere. According to the 6th Assessment Report of the Intergovernmental Panel on Climate Change, this planetary warming over multiple decades is human-driven and results in unpreceden...

https://www.seanoe.org/data/00765/87747/

We use an analog method, based on displacements of Argo floats at their parking depth (nominally located around 1,000 dbar) from ANDRO dataset, to compute continuous, likely trajectories and estimate the Lagrangian dispersion. From this, we find that the horizontal diffusivity coefficient has a median value around 500 m ² s ⁻¹ but is highly variabl...

The global ocean is warming and has absorbed 90% of the Earth Energy Imbalance over 2010–2018 leading to global mean sea level rise. Both ocean heat content (OHC) and sea level trends show large regional deviations from their global means. Both quantities have been estimated from in-situ observations for years. However, in-situ profile coverage is...

French Research vessels have been collecting thermo-salinometer (TSG) data since the early 2000 in contribution to the GOSUD programme. The set of homogeneous instruments is permanently monitored and regularly calibrated. Water samples are taken on a daily basis by the crew and later analysed in the laboratory. We present here the delayed mode proc...

Sea Surface Salinity (SSS) is an increasingly used Essential Ocean and Climate Variable. The Soil Moisture and Ocean Salinity (SMOS), Aquarius, and Soil Moisture Active Passive (SMAP) satellite missions all provide SSS measurements, with very different instrumental features leading to specific measurement characteristics. The Climate Change Initiat...

In the eastern Gulf of Guinea (GG), freshwater originated from rivers discharges into the ocean and high precipitation rate are key contributors to the upper ocean vertical density stratification, and play a key role in modulating local air‐sea interactions as well as biogeochemical cycle. Nevertheless, the dynamics of the GG freshwater plumes rema...

Variability of surface water masses of the Laptev and the East Siberian seas in August–September 2018 is studied using in situ and satellite data. In situ data were collected during the ARKTIKA-2018 expedition and then complemented with satellite-derived sea surface temperature (SST), salinity (SSS), sea surface height, wind speed, and sea ice conc...

Ten years of L-Band radiometric measurements have proven the capability of satellite Sea Surface Salinity (SSS) to resolve large scale to mesoscale SSS features in tropical to subtropical ocean. In mid to high latitude, L-Band measurements still suffer from large scale and time systematic errors. Here, a simple method is proposed to mitigate the la...

ICES Report on Ocean Climate (IROC) provides summary information on climatic conditions in the North Atlantic. The full-text of IROC is available at http://doi.org/10.17895/ices.pub.7537.

The international array of profiling floats known as Argo is a major component of the global ocean-and climate-observing system. In 2010, the NAOS (Novel Argo Observing System) project was selected as part of France's Equipex "Investissement d'Avenir" program. The objectives of NAOS were to consolidate the French contribution to the Argo core missi...

LOCEAN, LOPS, AARI and ACRI-ST have derived improved SMOS SSS maps over the Arctic Ocean based on new SST corrections and new sea ice filtering applied to SSS retrieved from SMOS satellite measurements. The first version of level 3 (L3) SMOS ARCTIC SSS (weekly and monthly) covers a period from June 2010 to November 2019 above 60°North. The dataset...

In the past two decades, the Argo Program has collected, processed, and distributed over two million vertical profiles of temperature and salinity from the upper two kilometers of the global ocean. A similar number of subsurface velocity observations near 1,000 dbar have also been collected. This paper recounts the history of the global Argo Progra...

Human-induced atmospheric composition changes cause a radiative imbalance at the top of the atmosphere which is driving global warming. This Earth energy imbalance (EEI) is the most critical number defining the prospects for continued global warming and climate change. Understanding the heat gain of the Earth system – and particularly how much and...

Future changes in subduction are suspected to be critical for the ocean deoxygenation predicted by climate models over the 21st century. However, the drivers of global oxygen subduction have not been fully described or quantified. Here, we address the physical mechanisms responsible for the oxygen transport across the late winter mixed layer base a...

Since 2010, the Soil Moisture and Ocean Salinity (SMOS) satellite mission monitors the earth emission at L-Band. It provides the longest time series of Sea Surface Salinity (SSS) from space over the global ocean. However, the SSS retrieval at high latitudes is a challenge because of the low sensitivity L-Band radiometric measurements to SSS in cold...

This study investigates the physical processes controlling the mixed layer buoyancy using a regional configuration of an ocean general circulation model. Processes are quantified by using a linearized equation of state, a mixed-layer heat, and a salt budget. Model results correctly reproduce the observed seasonal near-surface density tendencies. Th...

Operated since the end of 2009, the European Space Agency (ESA) Soil Moisture and Ocean Salinity (SMOS) satellite mission is the first orbiting radiometer that collects regular and global observations from space of two EssentialClimateVariablesoftheGlobalClimateObservingSystem:SeaSurfaceSalinity(SSS)andSoilMoisture. The National Aeronautics and Spac...

Abstract. Human-induced atmospheric composition changes cause a radiative imbalance at the top-of-atmosphere which is driving global warming. This Earth Energy Imbalance (EEI) is a fundamental metric of climate change. Understanding the heat gain of the Earth system from this accumulated heat – and particularly how much and where the heat is distri...

Since 2010, the Soil Moisture and Ocean Salinity (SMOS) satellite mission monitors the earth emission within L-Band, providing the longest time series of Sea Surface Salinity (SSS) from space over the global ocean. • SMOS has demonstrated its ability to monitor SSS in the Arctic Ocean ocean (Tarasenko et al. submitted and references herein). • In t...

Global mean sea level has experienced an unabated rise over the 20th century. This observed rise is due to both ocean warming and increasing continental freshwater discharge. We estimate the net ocean mass contribution to sea level by assessing the global ocean salt budget based on the unprecedented amount of in situ data over 2005–2015. We obtain...

Using an Argo dataset and the ECCOv4 reanalysis, a volume budget was performed to address the main mechanisms driving the volume change of the interior water masses in the Southern-Hemisphere oceans between 2006 and 2015. The subduction rates, and the isopycnal and diapycnal water-mass transformation were estimated in a density-spiciness (σ-τ) fram...

ICES Report on Ocean Climate (IROC) provides summary information on climatic conditions in the North Atlantic. The full-text of IROC is available at https://doi.org/10.17895/ices.pub.5461.

Interannual variability of Ocean Heat Content (OHC) is intimately linked to ocean water mass changes. Water mass characteristics are imprinted at the ocean surface and are modulated by climate variability on interannual to decadal time scales. In this study, we investigate the water mass change and their variability using an isopycnal decomposition...

The Argo Program has been implemented and sustained for almost two decades, as a global array of about 4000 profiling floats. Argo provides continuous observations of ocean temperature and salinity versus pressure, from the sea surface to 2000 dbar. The successful installation of the Argo array and its innovative data management system arose opport...

The Argo Program has been implemented and sustained for almost two decades, as a global array of about 4000 profiling floats. Argo provides continuous observations of ocean temperature and salinity versus pressure, from the sea surface to 2000 dbar. The successful installation of the Argo array and its innovative data management system arose opport...

The role ships play in atmospheric, oceanic, and biogeochemical observations is described with a focus on measurements made near the ocean surface. Ships include merchant and research vessels; cruise liners and ferries; fishing vessels; coast guard, military, and other government-operated ships; yachts; and a growing fleet of automated surface vess...

Variability of surface water masses of the Laptev and the East-Siberian seas in August-September 2018 is studied using in situ and satellite data. In situ data was collected during ARKTIKA-2018 expedition and then completed with satellite estimates of sea surface temperature (SST) and salinity (SSS), sea surface height, satellite-derived wind speed...

Recent advances in Sea Surface Salinity (SSS) remote sensing capabilities from the Soil Moisture and Ocean Salinity (SMOS) mission provide for the first time, a new overview on freshwater plumes. In the Eastern Gulf of Guinea, as far as we know, the freshwater plumes remains poorly documented from observations, because of data scarcity as well as t...

Advances in L-band microwave satellite radiometry in the past decade, pioneered by ESA’s SMOS and NASA’s Aquarius and SMAP missions, have demonstrated an unprecedented capability to observe global sea surface salinity (SSS) from space. Measurements from these missions are the only means to probe the very-near surface salinity (top cm), providing a...

The ICES (International Council for the Exploration of the Sea) Working Group on Oceanic Hydrography (WGOH) was established in the late 1970's with the aim of gathering experts in physical oceanography to provide regular science-based assessments of the North Atlantic hydrographical condition (basically termohaline fields). From the beginning, the...

ICES Report on Ocean Climate (IROC) provides summary information on climatic conditions in the North Atlantic. The full-text of IROC is available at http://doi.org/10.17895/ices.pub.4625.

Research on ocean heat content (OHC) show a warming of the global oceans over the last 60 years. While the North Atlantic has been an important contributor to this trend, during the last decade, ocean warming has been stronger in the subtropical southern hemisphere, At a given depth, this increase in the upper ocean OHC has been explained mainly by...

The West African seaboard is one of the upwelling sectors that has received the least attention, and in situ observations relevant to its dynamics are particularly scarce. The current system in this sector is not well known and understood, e.g., in terms of seasonal variability, across-shore structure, and forcing processes. This knowledge gap is a...

Salinity observing satellites have the potential to monitor river fresh-water plumes mesoscale spatio-temporal variations better than any other observing system. In the case of the Soil Moisture and Ocean Salinity (SMOS) satellite mission, this capacity was hampered due to the contamination of SMOS data processing by strong land-sea emissivity cont...

Glider measurements acquired along four transects between Cap-Vert Peninsula and the Cape Verde archipelago in the eastern tropical North Atlantic during March–April 2014 were used to investigate fine-scale stirring in an anticyclonic eddy. The anticyclone was formed near 12°N off the continental shelf and propagated northwest toward the Cape Verde...

The West African seaboard is one of the upwelling sectors that has received the least attention and in situ observations relevant to its dynamics are particularly scarce. The current system in this sector is not well known and understood, e.g., in terms of seasonal variability, across-shore structure, forcing processes. This knowledge gap is addres...