scholarly journals Fulfilling Observing System Implementation Requirements with the Global Drifter Array

2016 ◽  
Vol 33 (4) ◽  
pp. 685-695 ◽  
Author(s):  
Rick Lumpkin ◽  
Luca Centurioni ◽  
Renellys C. Perez
Keyword(s):  
Performance Indicator ◽  
Open Ocean ◽  
Global Ocean ◽  
Climate Variables ◽  
Velocity Measurements ◽  
External Sources ◽  
Surface Drifters ◽  
Ocean Observing ◽  
Equatorial Band

AbstractThe Global Ocean Observing System (GOOS) requirements for in situ surface temperature and velocity measurements call for observations at 5° × 5° resolution. A key component of the GOOS that measures these essential climate variables is the global array of surface drifters. In this study, statistical observing system sampling experiments are performed to evaluate how many drifters are required to achieve the GOOS requirements, both with and without the presence of a completed global tropical moored buoy array at 5°S–5°N. The statistics for these simulations are derived from the evolution of the actual global drifter array. It is concluded that drifters should be deployed within the near-equatorial band even though that band is also in principle covered by the tropical moored array, as the benefits of not doing so are marginal. It is also concluded that an optimal design half-life for the drifters is ~450 days, neglecting external sources of death, such as running aground or being picked up. Finally, it is concluded that comparing the drifter array size to the number of static 5° × 5° open-ocean bins is not an ideal performance indicator for system evaluation; a better performance indicator is the fraction of 5° × 5° open-ocean bins sampled, neglecting bins with high drifter death rates.

The Global Ocean Observing Component of IOOS: Implementation of the Initial Global Ocean Observing System for Climate and the Path Forward

2011 ◽  
Vol 45 (1) ◽  
pp. 9-18 ◽  
Author(s):  
Joel M. Levy ◽  
Derrick Snowden ◽  
Candyce Clark ◽  
Kathleen Crane ◽  
Howard J. Diamond ◽  
...  
Keyword(s):  
Global Climate ◽  
Global Ocean ◽  
Generation System ◽  
World Community ◽  
Design Goal ◽  
The Past ◽  
The World ◽  
Ocean Observing ◽  
The U.S

AbstractThe global ocean observing system for climate, which comprises the global in situ component of the U.S. Integrated Ocean Observing System, has now achieved about 61% of its initial design goal. Although this observing system, implemented cooperatively by over 70 countries worldwide, serves multiple applications, it is designed primarily to address climate requirements defined by the international Global Climate Observing System. The U.S. contribution to the system, described here, is implemented as an interdependent set of observational subsystems that constitute about half of the over 8,000 observing platforms deployed by the world community. Although much work remains to complete the initial global observing system, scientific advances of the past decade have identified the need to deploy a second-generation system that integrates biogeochemical and ecological observations with the primarily physical and carbon-related oceanographic observations that form the backbone of the initial observing system.

scholarly journals A seamless ensemble-based reconstruction of surface ocean pCO<sub>2</sub> and air–sea CO<sub>2</sub> fluxes over the global coastal and open oceans

2021 ◽  
Author(s):  
Thi Tuyet Trang Chau ◽  
Marion Gehlen ◽  
Frédéric Chevallier
Keyword(s):  
Equatorial Pacific ◽  
Open Ocean ◽  
The Arctic ◽  
Global Ocean ◽  
Surface Ocean ◽  
Continental Shelves ◽  
Open Sea ◽  
Northern Pacific ◽  
The Mean ◽  
Equatorial Band

Abstract. We have estimated the air–sea CO2 fluxes (fgCO2) over the global ocean from the open sea to the continental shelves. Fluxes and associated uncertainty were computed from an ensemble-based reconstruction of CO2 sea surface partial pressure (pCO2) maps trained with observations from the Surface Ocean CO2 Atlas v2020 database. The ensemble mean (which is the best estimate provided by the approach) fits independent data well and a broad agreement between the spatial distribution of model-data differences and the ensemble standard deviations (which are our model uncertainty estimate) is seen. The space-time varying uncertainty fields identify oceanic regions where improvements in data reconstruction and extensions of the observational network are needed. Poor reconstructions of pCO2 are primarily found over the coasts and/or in regions with sparse observations, while fgCO2 estimates with largest uncertainty are observed over the open Southern Ocean (44° S southward), the subpolar regions, the Indian gyre, and upwelling systems. Our estimate of the global net sink for the period 1985–2019 is 1.643 ± 0.125 PgC yr−1 including 0.150 ± 0.010 PgC yr−1 for the coastal net sink. Results suggest that the open ocean Subtropical Pacific (between 18° N–49° N) has the strongest CO2 sink (0.485 ± 0.014 PgC yr−1) among the basins of the world, followed by the open ocean sub-basins in the Southern hemisphere. The coastal Subpolar Atlantic (between 49° N–76° N) is the most significant coastal net sink, amounting to one third of the total coastal uptake; the northern Pacific continental shelves (north of 18° N) are the next contributors. The Equatorial Pacific (between 18° S–18° N) is the predominant source emitting 0.523 ± 0.016 PgC yr−1 of CO2 back to the atmosphere. Based on the mean flux density per unit area, the most intense CO2 drawdown is, however, observed over the Arctic (76° N poleward) followed by the Subpolar Atlantic and Subtropical Pacific for both open ocean and coastal sectors. The mean efflux density over the Equatorial Pacific remains the highest, but similar densities can also be found along other strong upwelling systems in the equatorial band.

Verification of Mercator Ocean global ocean forecasts

2021 ◽  
Author(s):  
Marie Drévillon ◽  
Charly Regnier ◽  
camille Sczcypta ◽  
Bruno Levier ◽  
Coralie Perruche ◽  
...  
Keyword(s):  
General Circulation ◽  
Circulation Model ◽  
Ocean General Circulation Model ◽  
Horizontal Resolution ◽  
Global Ocean ◽  
Trophic Chain ◽  
Marine Environment Monitoring ◽  
Monitoring Service ◽  
Ocean Observing

&lt;p&gt;Mercator Ocean, based in Toulouse, France, provides operational oceanography services, and is entrusted by the European Commission to implement the Copernicus Marine Environment Monitoring Service CMEMS. As part of these services, Mercator Ocean develops and operates ocean analysis and forecasting systems based on the Ocean General Circulation Model NEMO, assimilating satellite and in situ observations of the Global Ocean Observing System. The global ocean 10-day forecasts are updated daily, and their horizontal resolution is 1/12&amp;#176; (~9km), which allows describing accurately the largest mesoscale features in the ocean. Biogeochemical Ocean forecasts are also produced, at a coarser resolution (~ 25km), providing information on large categories planktons and nutrients which are the first levels of the trophic chain in the ocean. The verification of these physical and biogeochemical forecasts is based on standards developed by the GODAE/Oceanpredict community, and by the CMEMS product quality working group. In this presentation, we will discuss the metrics which are used, and their representativeness depending on the variable and on the reference observations that are available. &amp;#160;In particular, recent results from the comparison of several forecast lengths with observed velocities will be shown.&lt;/p&gt;

scholarly journals The current status of the real-time in situ Global Ocean Observing System for operational oceanography

2015 ◽  
Vol 8 (sup2) ◽  
pp. s189-s200 ◽  
Author(s):  
D.M. Legler ◽  
H.J. Freeland ◽  
R. Lumpkin ◽  
G. Ball ◽  
M.J. McPhaden ◽  
...  
Keyword(s):  
Real Time ◽  
Global Ocean ◽  
Current Status ◽  
The Real ◽  
Operational Oceanography ◽  
Ocean Observing

scholarly journals Air-Sea Interactions over Eddies in the Brazil-Malvinas Confluence

2021 ◽  
Vol 13 (7) ◽  
pp. 1335
Author(s):  
Ronald Souza ◽  
Luciano Pezzi ◽  
Sebastiaan Swart ◽  
Fabrício Oliveira ◽  
Marcelo Santini
Keyword(s):  
Latent Heat ◽  
Large Scale ◽  
Surface Wind ◽  
Heat Fluxes ◽  
Lower Atmosphere ◽  
Meteorological Variables ◽  
Global Ocean ◽  
Study Region ◽  
Cold Core

The Brazil–Malvinas Confluence (BMC) is one of the most dynamical regions of the global ocean. Its variability is dominated by the mesoscale, mainly expressed by the presence of meanders and eddies, which are understood to be local regulators of air-sea interaction processes. The objective of this work is to study the local modulation of air-sea interaction variables by the presence of either a warm (ED1) and a cold core (ED2) eddy, present in the BMC, during September to November 2013. The translation and lifespans of both eddies were determined using satellite-derived sea level anomaly (SLA) data. Time series of satellite-derived surface wind data, as well as these and other meteorological variables, retrieved from ERA5 reanalysis at the eddies’ successive positions in time, allowed us to investigate the temporal modulation of the lower atmosphere by the eddies’ presence along their translation and lifespan. The reanalysis data indicate a mean increase of 78% in sensible and 55% in latent heat fluxes along the warm eddy trajectory in comparison to the surrounding ocean of the study region. Over the cold core eddy, on the other hand, we noticed a mean reduction of 49% and 25% in sensible and latent heat fluxes, respectively, compared to the adjacent ocean. Additionally, a field campaign observed both eddies and the lower atmosphere from ship-borne observations before, during and after crossing both eddies in the study region during October 2013. The presence of the eddies was imprinted on several surface meteorological variables depending on the sea surface temperature (SST) in the eddy cores. In situ oceanographic and meteorological data, together with high frequency micrometeorological data, were also used here to demonstrate that the local, rather than the large scale forcing of the eddies on the atmosphere above, is, as expected, the principal driver of air-sea interaction when transient atmospheric systems are stable (not actively varying) in the study region. We also make use of the in situ data to show the differences (biases) between bulk heat flux estimates (used on atmospheric reanalysis products) and eddy covariance measurements (taken as “sea truth”) of both sensible and latent heat fluxes. The findings demonstrate the importance of short-term changes (minutes to hours) in both the atmosphere and the ocean in contributing to these biases. We conclude by emphasizing the importance of the mesoscale oceanographic structures in the BMC on impacting local air-sea heat fluxes and the marine atmospheric boundary layer stability, especially under large scale, high-pressure atmospheric conditions.

Estimating Global Ocean Heat Content Changes in the Upper 1800 m since 1950 and the Influence of Climatology Choice*

2014 ◽  
Vol 27 (5) ◽  
pp. 1945-1957 ◽  
Author(s):  
John M. Lyman ◽  
Gregory C. Johnson
Keyword(s):  
Heat Content ◽  
Ocean Heat Content ◽  
Global Ocean ◽  
Ocean Temperature ◽  
Vertical Separation ◽  
Ocean Heat Uptake ◽  
Expendable Bathythermograph ◽  
Heat Uptake ◽  
The Mean

Abstract Ocean heat content anomalies are analyzed from 1950 to 2011 in five distinct depth layers (0–100, 100–300, 300–700, 700–900, and 900–1800 m). These layers correspond to historic increases in common maximum sampling depths of ocean temperature measurements with time, as different instruments—mechanical bathythermograph (MBT), shallow expendable bathythermograph (XBT), deep XBT, early sometimes shallower Argo profiling floats, and recent Argo floats capable of worldwide sampling to 2000 m—have come into widespread use. This vertical separation of maps allows computation of annual ocean heat content anomalies and their sampling uncertainties back to 1950 while taking account of in situ sampling advances and changing sampling patterns. The 0–100-m layer is measured over 50% of the globe annually starting in 1956, the 100–300-m layer starting in 1967, the 300–700-m layer starting in 1983, and the deepest two layers considered here starting in 2003 and 2004, during the implementation of Argo. Furthermore, global ocean heat uptake estimates since 1950 depend strongly on assumptions made concerning changes in undersampled or unsampled ocean regions. If unsampled areas are assumed to have zero anomalies and are included in the global integrals, the choice of climatological reference from which anomalies are estimated can strongly influence the global integral values and their trend: the sparser the sampling and the bigger the mean difference between climatological and actual values, the larger the influence.

scholarly journals Consistency of the current global ocean observing systems from an Argo perspective

Ocean Science ◽  
2014 ◽  
Vol 10 (3) ◽  
pp. 547-557 ◽  
Author(s):  
K. von Schuckmann ◽  
J.-B. Sallée ◽  
D. Chambers ◽  
P.-Y. Le Traon ◽  
C. Cabanes ◽  
...  
Keyword(s):  
Sea Level ◽  
Heat Content ◽  
Deep Ocean ◽  
Global Ocean ◽  
Regional Variability ◽  
Tropical Ocean ◽  
Steric Sea Level ◽  
Ocean Observing ◽  
Ocean Observing Systems ◽  
Observing Systems

Abstract. Variations in the world's ocean heat storage and its associated volume changes are a key factor to gauge global warming and to assess the earth's energy and sea level budget. Estimating global ocean heat content (GOHC) and global steric sea level (GSSL) with temperature/salinity data from the Argo network reveals a positive change of 0.5 ± 0.1 W m−2 (applied to the surface area of the ocean) and 0.5 ± 0.1 mm year−1 during the years 2005 to 2012, averaged between 60° S and 60° N and the 10–1500 m depth layer. In this study, we present an intercomparison of three global ocean observing systems: the Argo network, satellite gravimetry from GRACE and satellite altimetry. Their consistency is investigated from an Argo perspective at global and regional scales during the period 2005–2010. Although we can close the recent global ocean sea level budget within uncertainties, sampling inconsistencies need to be corrected for an accurate global budget due to systematic biases in GOHC and GSSL in the Tropical Ocean. Our findings show that the area around the Tropical Asian Archipelago (TAA) is important to closing the global sea level budget on interannual to decadal timescales, pointing out that the steric estimate from Argo is biased low, as the current mapping methods are insufficient to recover the steric signal in the TAA region. Both the large regional variability and the uncertainties in the current observing system prevent us from extracting indirect information regarding deep-ocean changes. This emphasizes the importance of continuing sustained effort in measuring the deep ocean from ship platforms and by beginning a much needed automated deep-Argo network.

Soil Liquefaction Evaluation of Offshore Site Based on In Situ Shear Wave Velocity Measurements

2013 ◽  
Vol 405-408 ◽  
pp. 470-473
Author(s):  
Sheng Jie Di ◽  
Ming Yuan Wang ◽  
Zhi Gang Shan ◽  
Hai Bo Jia
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Wind Farm ◽  
Soil Liquefaction ◽  
Offshore Wind ◽  
Velocity Measurements ◽  
Liquefaction Resistance ◽  
Liquefaction Potential

A procedure for evaluating liquefaction resistance of soils based on the shear wave velocity measurements is outlined in the paper. The procedure follows the general formal of the Seed-Idriss simplified procedure. In addition, it was developed following suggestions from industry, researchers, and practitioners. The procedure correctly predicts moderate to high liquefaction potential for over 95% of the liquefaction case histories. The case study for the site of offshore wind farm in Jiangsu province is provided to illustrate the application of the proposed procedure. The feature of the soils and the shear wave velocity in-situ tested in site are discussed and the liquefaction potential of the layer is evaluated. The application shows that the layers of the non-cohesive soils in the depths 3-11m may be liquefiable according to the procedure.

scholarly journals Dake Chen: unraveling the secrets of ocean–climate interaction

2017 ◽  
Vol 4 (1) ◽  
pp. 136-139 ◽  
Author(s):  
Ling Wang
Keyword(s):  
Ocean Dynamics ◽  
Global Ocean ◽  
Practical Applications ◽  
Ocean Climate ◽  
Ocean Science ◽  
National Strategic Plan ◽  
Ocean Atmosphere Interaction ◽  
Atmosphere Interaction ◽  
Academy Of Sciences ◽  
Ocean Observing

Abstract The ocean is a complex and mysterious system that attracts scientists around the world to unravel its secrets. Dake Chen, a distinguished physical oceanographer and an academician of the Chinese Academy of Sciences, is one of them. Since the mid-1980s, he has been studying ocean dynamics and ocean–atmosphere interaction, and has made seminal contributions to the understanding and prediction of short-term climate variability, especially the El Niño phenomenon. In a recent interview with NSR, Professor Dake Chen says that China has made significant progress in recent years in ocean research, but, in order to make breakthroughs in the field of oceanography, China needs to further expand the scope of research programs from coastal seas to open oceans, to greatly increase the investment in global ocean-observing systems and to pay more attention to fundamental scientific problems in addition to practical applications. He also calls for a better-defined national strategic plan for ocean science and technology.

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