Marine Carbon BiogeochemistryBiogeochemical Cycles and ClimateGlobal Biogeochemical Cycles in the Climate SystemOcean Dynamics and the Carbon CycleLive Long and EvolveBiogeochemistry of Marine Dissolved Organic MatterOcean Biogeochemical DynamicsMarine Ecosystems and Global ChangeBiological OceanographyNitrogen in the SeaBiogeochemistry of EstuariesInteractions of C, N, P and S Biogeochemical Cycles and Global ChangeGlobal EnvironmentComputational Science — ICCS 2004The Oceans and ClimateMarine Microbiome and Biogeochemical Cycles in Marine Productive AreasMetal Ions in Biological Systems, Volume 43 Biogeochemical Cycles of ElementsNitrogen in the Marine EnvironmentIntroduction to Marine BiogeochemistryOcean Circulation and ClimatePrimary Productivity and Biogeochemical Cycles in the SeaThe Biogeochemical Cycle of Silicon in the OceanChemical OceanographyTowards a Model of Ocean Biogeochemical ProcessesOcean Dynamics and the Carbon CycleOcean BiogeochemistryParticle Analysis in OceanographyBiogeochemical CyclesBiogeochemical Dynamics at Major River-Coastal InterfacesThe Ocean Carbon Cycle and ClimateSensitivity of global ocean biogeochemical dynamics to ecosystem structure in a future climateModeling Methods for Marine ScienceAn Introduction to the Chemistry of the SeaEncyclopedia of Ocean SciencesCO2 in Seawater: Equilibrium, Kinetics, IsotopesThe Biogeochemical Cycle of Silicon in the OceanKuroshio CurrentThe Mediterranean Sea in the Era of Global Change 1Ocean Biogeochemical DynamicsOcean Mixing

Ocean Biogeochemical Dynamics

. The ECMWF OCEAN5 system is a global ocean and sea-ice ensemble of reanalysis and real-time analysis. This paper gives a full description
of the OCEAN5 system, with the focus on upgrades of system components with
respect to its predecessors, ORAS4 and ORAP5. An important novelty in OCEAN5
is the ensemble generation strategy that includes perturbation of initial
conditions and a generic perturbation scheme for observations and forcing
fields. Other upgrades include revisions to the a priori bias correction
scheme, observation quality control and assimilation method for sea-level
anomalies. The OCEAN5 historical reconstruction of the ocean and sea-ice
state is the ORAS5 reanalysis, which includes five ensemble members and covers
the period from 1979 onwards. Updated versions of observation data sets are
used in ORAS5 production, with special attention devoted to the consistency
of sea surface temperature (SST) and sea-ice observations. Assessment of
ORAS5 through sensitivity experiments suggests that all system components
contribute to an improved fit to observation in reanalyses, with the most
prominent contribution from direct assimilation of ocean in situ
observations. Results of observing system experiments further suggest that
the Argo float is the most influential observation type in our data assimilation
system. Assessment of ORAS5 has also been carried out for several key ocean
state variables and verified against reference climate data sets from the ESA CCI (European Space Agency Climate Change Initiative) project. With respect to ORAS4, ORAS5 has improved ocean climate state and
variability in terms of SST and sea level, mostly due to increased model
resolution and updates in assimilated observation data sets. In spite of the
improvements, ORAS5 still underestimates the temporal variance of sea level and continues exhibiting large SST biases in the Gulf Stream and its extension
regions which are possibly associated with misrepresentation of front
positions. Overall, the SST and sea-ice uncertainties estimated using five
ORAS5 ensemble members have spatial patterns consistent with those of
analysis error. The ensemble spread of sea ice is commensurable with the
sea-ice analysis error. On the contrary, the ensemble spread is
under-dispersive for SST.

/pdf/the-ecmwf-operational-ensemble-reanalysis-analysis-system-57rbutn32u.pdf

The ECMWF operational ensemble reanalysis–analysis system for ocean and sea ice: a description of the system and assessment

. For more than 20 years, the multi-satellite Data Unification and Altimeter Combination System (DUACS) has been providing near-real-time (NRT) and delayed-time (DT) altimetry products. DUACS datasets range from along-track measurements to multi-mission sea level anomaly (SLA) and absolute dynamic topography (ADT) maps. The DUACS DT2018 ensemble of products is the most recent and major release. For this, 25 years of altimeter data have been reprocessed and are available through the Copernicus Marine Environment Monitoring Service (CMEMS) and the Copernicus Climate Change Service (C3S). Several changes were implemented in DT2018 processing in order to improve
the product quality. New altimetry standards and geophysical corrections
were used, data selection was refined and optimal interpolation (OI)
parameters were reviewed for global and regional map generation. This paper describes the extensive assessment of DT2018 reprocessing. The
error budget associated with DT2018 products at global and regional scales
was defined and improvements on the previous version were quantified
(DT2014; Pujol et al., 2016). DT2018 mesoscale errors were estimated using
independent and in situ measurements. They have been reduced by nearly 3 % to 4 % for global and regional products compared to DT2014. This reduction is even greater in coastal areas (up to 10 %) where it is directly linked to the geophysical corrections applied to DT2018 processing. The conclusions are very similar concerning geostrophic currents, for which error was globally reduced by around 5 % and as much as 10 % in coastal areas.

/pdf/duacs-dt2018-25-years-of-reprocessed-sea-level-altimetry-113kqz9j8v.pdf

DUACS DT2018: 25 years of reprocessed sea level altimetry products

A much-anticipated 'monster' El Nino failed to materialize in 2014, whereas an unforeseen strong El Nino is developing in 2015. El Nino continues to surprise us, despite decades of research into its causes. Natural variations most probably account for recent events, but climate change may also have played a role.

Playing Hide and Seek with El Niño

. 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 where the heat is
distributed – is fundamental to understanding how this affects warming
ocean, atmosphere and land; rising surface temperature; sea level; and loss
of grounded and floating ice, which are fundamental concerns for society.
This study is a Global Climate Observing System (GCOS) concerted
international effort to update the Earth heat inventory and presents an
updated assessment of ocean warming estimates as well as new and updated estimates
of heat gain in the atmosphere, cryosphere and land over the period
1960–2018. The study obtains a consistent long-term Earth system heat gain
over the period 1971–2018, with a total heat gain of 358±37  ZJ,
which is equivalent to a global heating rate of 0.47±0.1  W m −2 .
Over the period 1971–2018 (2010–2018), the majority of heat gain is reported
for the global ocean with 89 % (90 %), with 52 % for both periods in
the upper 700 m depth, 28 % (30 %) for the 700–2000 m depth layer and 9 % (8 %) below 2000 m depth. Heat gain over land amounts to 6 %
(5 %) over these periods, 4 % (3 %) is available for the melting of
grounded and floating ice, and 1 % (2 %) is available for atmospheric warming. Our
results also show that EEI is not only continuing, but also increasing: the EEI
amounts to 0.87±0.12  W m −2 during 2010–2018. Stabilization of
climate, the goal of the universally agreed United Nations Framework Convention on Climate
Change (UNFCCC) in 1992 and the Paris
Agreement in 2015, requires that EEI be reduced to approximately zero to
achieve Earth's system quasi-equilibrium. The amount of CO2 in the
atmosphere would need to be reduced from 410 to 353 ppm to increase heat
radiation to space by 0.87 W m −2 , bringing Earth back towards energy
balance. This simple number, EEI, is the most fundamental metric that the
scientific community and public must be aware of as the measure of how well
the world is doing in the task of bringing climate change under control, and
we call for an implementation of the EEI into the global stocktake based on
best available science. Continued quantification and reduced uncertainties
in the Earth heat inventory can be best achieved through the maintenance of
the current global climate observing system, its extension into areas of
gaps in the sampling, and the establishment of an international framework for
concerted multidisciplinary research of the Earth heat inventory as
presented in this study. This Earth heat inventory is published at the German Climate Computing Centre (DKRZ, https://www.dkrz.de/ , last access: 7 August 2020) under the DOI
 https://doi.org/10.26050/WDCC/GCOS_EHI_EXP_v2 
(von Schuckmann et al., 2020).

/pdf/heat-stored-in-the-earth-system-where-does-the-energy-go-3wifbsbpti.pdf

Heat stored in the Earth system: where does the energy go?

Introduction — s1 Chapter 1: Essential Variables — s4  1.1 Ocean temperature and salinity  Sandrine Mulet, Bruno Buongiorno Nardelli, Simon Good, Andrea Pisano, Eric Greiner, Maeva Monier, Emmanuel...

Tanguy Szerkely

Papers

Copernicus Marine Service Ocean State Report