scholarly journals Measuring the Pulse of Earth's Global Ocean: Ocean Sound and Marine Life Interagency Working Group

2021 ◽  
Vol 55 (3) ◽  
pp. 76-77
Author(s):  
Robert P. Dziak
Keyword(s):  
Inclusive Education ◽  
Deep Ocean ◽  
Marine Ecosystems ◽  
Global Ocean ◽  
Outreach Program ◽  
Marine Animals ◽  
Private Industry ◽  
Sound Levels ◽  
Ocean Noise ◽  
The Impact

Abstract The “Measuring the Pulse of Earth's Global Ocean” project will attempt to quantify sound levels in what should be the quietest parts of the ocean—the five deepest locations—to gauge the baseline level of sound in these remote ocean areas. Ocean noise from human-made sources of sound (e.g., shipping) can have a detrimental effect on marine animals that use sound to sense their environment. Thus noise can negatively impact the health of marine ecosystems, which are the basis for many sectors of the global “Blue” economy, including commercial fisheries and aquaculture. This project will gather unique baseline data to monitor the “acoustic health” of the oceans. A novel, deep-ocean capable hydrophone-lander system will be deployed at each of these five deep-sea sites (all >7 km deep). The project will involve the collaboration of several U.S. governmental agencies, private industry and NGOs, and international partners to access these global locations. We will collaborate with scientists from each of these five sites to deploy, recover, and analyze this deep ocean acoustic data. Our ocean sound program aspires to develop a robust and inclusive education/outreach program, focusing on the impact of underwater noise on the health of marine ecosystems.

On the impact of sea ice in a global ocean circulation model

1997 ◽  
Vol 25 ◽  
pp. 111-115 ◽  
Author(s):  
Achim Stössel
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Ocean Circulation ◽  
General Circulation ◽  
Thermohaline Circulation ◽  
Circulation Model ◽  
Deep Ocean ◽  
Global Ocean ◽  
Convective Activity ◽  
The Impact

This paper investigates the long-term impact of sea ice on global climate using a global sea-ice–ocean general circulation model (OGCM). The sea-ice component involves state-of-the-art dynamics; the ocean component consists of a 3.5° × 3.5° × 11 layer primitive-equation model. Depending on the physical description of sea ice, significant changes are detected in the convective activity, in the hydrographic properties and in the thermohaline circulation of the ocean model. Most of these changes originate in the Southern Ocean, emphasizing the crucial role of sea ice in this marginally stably stratified region of the world's oceans. Specifically, if the effect of brine release is neglected, the deep layers of the Southern Ocean warm up considerably; this is associated with a weakening of the Southern Hemisphere overturning cell. The removal of the commonly used “salinity enhancement” leads to a similar effect. The deep-ocean salinity is almost unaffected in both experiments. Introducing explicit new-ice thickness growth in partially ice-covered gridcells leads to a substantial increase in convective activity, especially in the Southern Ocean, with a concomitant significant cooling and salinification of the deep ocean. Possible mechanisms for the resulting interactions between sea-ice processes and deep-ocean characteristics are suggested.

scholarly journals Major improvement of altimetry sea level estimations using pressure derived corrections based on ERA-interim atmospheric reanalysis

2016 ◽  
Author(s):  
L. Carrere ◽  
Y. Faugère ◽  
M. Ablain
Keyword(s):  
Shallow Water ◽  
Sea Level ◽  
Positive Impact ◽  
Regional Scale ◽  
Atmospheric Correction ◽  
Deep Ocean ◽  
Global Ocean ◽  
Strong Impact ◽  
Residual Variance ◽  
The Impact

Abstract. New Dynamic Atmospheric Correction (DAC) and Dry Tropospheric (DT) correction derived from the ERA-Interim meteorological reanalysis have been computed on the 1992-2013 altimeter period. Using these new corrections improves significantly sea-level estimations for short temporal signals (< 2 months); the impact is stronger if considering old altimeter missions (ERS-1, ERS-2, TP), for which DAC_ERA allows reducing the residual variance at crossovers by more than 10 cm2 in the Southern Ocean and in some shallow water regions. The impact of DT_ERA is also significant in the southern high latitudes for these missions. Using the ERA-interim forcing has the greatest positive impact on the first decade of altimetry, then this impact diminishes until giving similar results as the operational forcing from year 2002. Concerning more recent missions (Jason-1, Jason-2, and Envisat), results are very similar between ERA-Interim and ECMWF based corrections: on average on global ocean, the operational DAC becomes slightly better than DAC_ERA only from year 2006, likely due to the switch to a higher resolution of operational forcing. At regional scale, both DACs are similar in deep ocean but DAC_ERA raises the residual crossovers variance in some shallow water regions. On the second decade of altimetry, unexpectedly DT_ERA still gives better results compared to the operational DT. Concerning climate signals, both DAC_ERA and DT_ERA have a low impact on global MSL trend, but they can have a strong impact on long-term regional trends estimation, until several mm/yr locally.

scholarly journals Influence of consumer-driven nutrient recycling on primary production and the distribution of N and P in the ocean

2010 ◽  
Vol 7 (4) ◽  
pp. 1285-1305 ◽  
Author(s):  
A. Nugraha ◽  
P. Pondaven ◽  
P. Tréguer
Keyword(s):  
Primary Production ◽  
N2 Fixation ◽  
Nutrient Recycling ◽  
Deep Ocean ◽  
Global Ocean ◽  
N:P Ratios ◽  
Limiting Nutrient ◽  
Consumer Interactions ◽  
The Impact ◽  
N And P Cycling

Abstract. In this study we investigated the impact of consumer-driven nutrient recycling (CNR) on oceanic primary production and the distribution of nitrogen (N) and phosphorus (P) in the deep ocean. For this purpose, we used and extended two existing models: a 2-box model of N and P cycling in the global ocean (Tyrrell, 1999), and the model of Sterner (1990) which formalised the principles of CNR theory. The resulting model showed that marine herbivores may affect the supply and the stoichiometry of N and P in the ocean, thereby exerting a control on global primary production. The predicted global primary production was higher when herbivores were included in the model, particularly when these herbivores had higher N:P ratios than phytoplankton. This higher primary production was triggered by a low N:P resupply ratio, which, in turn, favoured the P-limited N2-fixation and eventually the N-limited non-fixers. Conversely, phytoplankton with higher N:P ratios increased herbivore yield until phosphorus became the limiting nutrient, thereby favouring herbivores with a low P-requirement. Finally, producer-consumer interactions fed back on the N and P inventories in the deep ocean through differential nutrient recycling. In this model, N deficit or N excess in the deep ocean resulted not only from the balance between N2-fixation and denitrification, but also from CNR, especially when the elemental composition of producers and consumers differed substantially. Although the model is fairly simple, these results emphasize our need for a better understanding of how consumers influence nutrient recycling in the ocean.

scholarly journals The Southern Hemisphere Westerlies in a Warming World: Propping Open the Door to the Deep Ocean

2006 ◽  
Vol 19 (24) ◽  
pp. 6382-6390 ◽  
Author(s):  
Joellen L. Russell ◽  
Keith W. Dixon ◽  
Anand Gnanadesikan ◽  
Ronald J. Stouffer ◽  
J. R. Toggweiler
Keyword(s):  
Carbon Dioxide ◽  
Southern Ocean ◽  
Climate Model ◽  
Deep Ocean ◽  
Global Ocean ◽  
Westerly Winds ◽  
Anthropogenic Carbon ◽  
Warming World ◽  
The Impact ◽  
Anthropogenic Carbon Dioxide

Abstract A coupled climate model with poleward-intensified westerly winds simulates significantly higher storage of heat and anthropogenic carbon dioxide by the Southern Ocean in the future when compared with the storage in a model with initially weaker, equatorward-biased westerlies. This difference results from the larger outcrop area of the dense waters around Antarctica and more vigorous divergence, which remains robust even as rising atmospheric greenhouse gas levels induce warming that reduces the density of surface waters in the Southern Ocean. These results imply that the impact of warming on the stratification of the global ocean may be reduced by the poleward intensification of the westerlies, allowing the ocean to remove additional heat and anthropogenic carbon dioxide from the atmosphere.

scholarly journals Influence of consumer-driven nutrient recycling on primary production and the distribution of N and P in the ocean

2010 ◽  
Vol 7 (1) ◽  
pp. 111-164
Author(s):  
A. Nugraha ◽  
P. Pondaven ◽  
P. Tréguer
Keyword(s):  
Primary Production ◽  
N2 Fixation ◽  
Nutrient Recycling ◽  
Deep Ocean ◽  
Global Ocean ◽  
N:P Ratios ◽  
Limiting Nutrient ◽  
Consumer Interactions ◽  
The Impact ◽  
N And P Cycling

Abstract. In this study we investigated the impact of consumer-driven nutrient recycling (CNR) on oceanic primary production and the distribution of nitrogen (N) and phosphorus (P) in the deep ocean. For this purpose, we used and extended two existing models: a 2-box model of N and P cycling in the global ocean (Tyrrell, 1999), and the model of Sterner (1990) which formalised the principles of CNR theory. The resulting model showed that marine herbivores may affect the supply and the stoichiometry of N and P in the ocean, thereby exerting a control on global primary production. The predicted global primary production was higher when herbivores were included in the model, particularly when these herbivores had higher N:P ratios than phytoplankton. This higher primary production was triggered by a low N:P resupply ratio, which, in turn, favoured the P-limited N2-fixation and eventually the N-limited non-fixers. Conversely, phytoplankton with higher N:P ratios increased herbivore yield until phosphorus became the limiting nutrient, thereby favouring herbivores with a low P-requirement. Finally, producer-consumer interactions fed back on the N and P inventories in the deep ocean through differential nutrient recycling. In this model, N deficit or N excess in the deep ocean resulted not only from the balance between N2-fixation and denitrification, but also from CNR, especially when the elemental composition of producers and consumers differed substantially. Although the model is fairly simply, these results emphasize our need for a better understanding of how consumers influence nutrient recycling in the ocean.

scholarly journals Major improvement of altimetry sea level estimations using pressure-derived corrections based on ERA-Interim atmospheric reanalysis

Ocean Science ◽  
2016 ◽  
Vol 12 (3) ◽  
pp. 825-842 ◽  
Author(s):  
Loren Carrere ◽  
Yannice Faugère ◽  
Michaël Ablain
Keyword(s):  
Shallow Water ◽  
Sea Level ◽  
Regional Scale ◽  
Atmospheric Correction ◽  
Deep Ocean ◽  
Global Ocean ◽  
Strong Impact ◽  
Global Mean Sea Level ◽  
Along Track ◽  
The Impact

Abstract. The new dynamic atmospheric correction (DAC) and dry tropospheric (DT) correction derived from the ERA-Interim meteorological reanalysis have been computed for the 1992–2013 altimeter period. Using these new corrections significantly improves sea level estimations for short temporal signals (< 2 months); the impact is stronger if considering old altimeter missions (ERS-1, ERS-2, and Topex/Poseidon), for which DAC_ERA (DAC derived from ERA-Interim meteorological reanalysis) allows reduction of the along-track altimeter sea surface height (SSH) error by more than 3 cm in the Southern Ocean and in some shallow water regions. The impact of DT_ERA (DT derived from ERA-Interim meteorological reanalysis) is also significant in the southern high latitudes for these missions. Concerning more recent missions (Jason-1, Jason-2, and Envisat), results are very similar between ERA-Interim and ECMWF-based corrections: on average for the global ocean, the operational DAC becomes slightly better than DAC_ERA only from the year 2006, likely due to the switch of the operational forcing to a higher spatial resolution. At regional scale, both DACs are similar in the deep ocean but DAC_ERA raises the residual crossovers' variance in some shallow water regions, indicating a slight degradation in the most recent years of the study. In the second decade of altimetry, unexpectedly DT_ERA still gives better results compared to the operational DT. Concerning climate signals, both DAC_ERA and DT_ERA have a low impact on global mean sea level rise (MSL) trends, but they can have a strong impact on long-term regional trends' estimation, up to several millimeters per year locally.

scholarly journals On the impact of sea ice in a global ocean circulation model

1997 ◽  
Vol 25 ◽  
pp. 111-115 ◽  
Author(s):  
Achim Stössel
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Ocean Circulation ◽  
General Circulation ◽  
Thermohaline Circulation ◽  
Circulation Model ◽  
Deep Ocean ◽  
Global Ocean ◽  
Convective Activity ◽  
The Impact

This paper investigates the long-term impact of sea ice on global climate using a global sea-ice–ocean general circulation model (OGCM). The sea-ice component involves state-of-the-art dynamics; the ocean component consists of a 3.5° × 3.5° × 11 layer primitive-equation model. Depending on the physical description of sea ice, significant changes are detected in the convective activity, in the hydrographic properties and in the thermohaline circulation of the ocean model. Most of these changes originate in the Southern Ocean, emphasizing the crucial role of sea ice in this marginally stably stratified region of the world's oceans. Specifically, if the effect of brine release is neglected, the deep layers of the Southern Ocean warm up considerably; this is associated with a weakening of the Southern Hemisphere overturning cell. The removal of the commonly used “salinity enhancement” leads to a similar effect. The deep-ocean salinity is almost unaffected in both experiments. Introducing explicit new-ice thickness growth in partially ice-covered gridcells leads to a substantial increase in convective activity, especially in the Southern Ocean, with a concomitant significant cooling and salinification of the deep ocean. Possible mechanisms for the resulting interactions between sea-ice processes and deep-ocean characteristics are suggested.

The CMEMS In Situ TAC multi-year and multi-variate products to monitor and understand the ocean variability

2021 ◽  
Author(s):  
Tanguy Szekely ◽  
Mélanie Juza ◽  
Jérôme Gourrion ◽  
Paz Rotllán-García ◽  
Sylvie Pouliquen ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
Marine Ecosystem ◽  
Deep Ocean ◽  
Global Ocean ◽  
Polar Regions ◽  
Temporal Scales ◽  
Essential Information ◽  
The Impact

&lt;p&gt;The CMEMS In Situ TAC (INSTAC) integrates &lt;em&gt;in situ&lt;/em&gt; observations from various platforms, (e.g. profiling floats, gliders, drifters, saildrones, research vessels, ferryboxes, fixed stations, tides gauges, sea mammals, high-frequency radar), providing physical and biogeochemical ocean data at local, regional and global scales, with an increasing data integration from the polar and coastal regions.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;The INSTAC quality-controlled data in both delayed mode and near-real time are contributing to support the operational oceanography (e.g. model forecasting, analysis and reanalysis, satellite calibration, downstream services) and to monitor the 4-dimensional ocean at various spatial and temporal scales. The INSTAC multi-year products provide an essential information on the ocean state, variability and changes and allow addressing long-term variations (climate) analysis as well as detecting remarkable events. Hence, the INSTAC group has contributed substantially to the elaboration of the annual CMEMS Ocean State Report (OSR, &lt;em&gt;Von Schuckmann et al.&lt;/em&gt;, 2016, 2018, 2019, 2020, 2021).&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;A general overview of the INSTAC contributions to the CMEMS OSR is presented, highlighting its capacity to describe, analyze and understand the ocean state and variability of both physical and biogeochemical components from the sea surface to the deep ocean, from the coastal to open sea waters, from tropical to polar regions, from semi-enclosed seas to the global ocean, from short-term to long-term temporal scales. The INSTAC team contributes to the CMEMS Ocean Monitoring Indicators reporting, investigates the ocean circulation variability, analyses the impact of climate change on marine ecosystem and ocean circulation, and develops operational applications and services.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Maintaining the current observational network, integrating new platforms, enhancing the spatial and temporal resolutions, improving methodologies and developing new metrics (e.g. quality control, data assimilation), developing new products, INSTAC will continue to serve the overall need to understand and predict the ocean state and variability, in line with the present and future scientific, societal and environmental challenges.&lt;/p&gt;

scholarly journals The role of ocean transport in the uptake of anthropogenic CO<sub>2</sub>

2009 ◽  
Vol 6 (3) ◽  
pp. 375-390 ◽  
Author(s):  
L. Cao ◽  
M. Eby ◽  
A. Ridgwell ◽  
K. Caldeira ◽  
D. Archer ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Co2 Emissions ◽  
Deep Ocean ◽  
Global Ocean ◽  
Co2 Uptake ◽  
Strongly Correlated ◽  
Pulse Emission ◽  
Anthropogenic Co2 ◽  
The Impact

Abstract. We compare modeled oceanic carbon uptake in response to pulse CO2 emissions using a suite of global ocean models and Earth system models. In response to a CO2 pulse emission of 590 Pg C (corresponding to an instantaneous doubling of atmospheric CO2 from 278 to 556 ppm), the fraction of CO2 emitted that is absorbed by the ocean is: 37±8%, 56±10%, and 81±4% (model mean ±2σ ) in year 30, 100, and 1000 after the emission pulse, respectively. Modeled oceanic uptake of pulse CO2 on timescales from decades to about a century is strongly correlated with simulated present-day uptake of chlorofluorocarbons (CFCs) and CO2 across all models, while the amount of pulse CO2 absorbed by the ocean from a century to a millennium is strongly correlated with modeled radiocarbon in the deep Southern and Pacific Ocean. However, restricting the analysis to models that are capable of reproducing observations within uncertainty, the correlation is generally much weaker. The rates of surface-to-deep ocean transport are determined for individual models from the instantaneous doubling CO2 simulations, and they are used to calculate oceanic CO2 uptake in response to pulse CO2 emissions of different sizes pulses of 1000 and 5000 Pg C. These results are compared with simulated oceanic uptake of CO2 by a number of models simulations with the coupling of climate-ocean carbon cycle and without it. This comparison demonstrates that the impact of different ocean transport rates across models on oceanic uptake of anthropogenic CO2 is of similar magnitude as that of climate-carbon cycle feedbacks in a single model, emphasizing the important role of ocean transport in the uptake of anthropogenic CO2.

Case study: Prediction and field tests of railway noise and effects of a low-height noise barrier

2020 ◽  
Vol 68 (4) ◽  
pp. 303-314
Author(s):  
Yuna Park ◽  
Hyo-In Koh ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
...  
Keyword(s):  
High Speed ◽  
Field Tests ◽  
Residential Areas ◽  
Railway Systems ◽  
Railway Noise ◽  
Sound Levels ◽  
Noise Barrier ◽  
The Difference ◽  
Reduction Effect ◽  
The Impact

Railway noise is calculated to predict the impact of new or reconstructed railway tracks on nearby residential areas. The results are used to prepare adequate counter- measures, and the calculation results are directly related to the cost of the action plans. The calculated values were used to produce noise maps for each area of inter- est. The Schall 03 2012 is one of the most frequently used methods for the production of noise maps. The latest version was released in 2012 and uses various input para- meters associated with the latest rail vehicles and track systems in Germany. This version has not been sufficiently used in South Korea, and there is a lack of standard guidelines and a precise manual for Korean railway systems. Thus, it is not clear what input parameters will match specific local cases. This study investigates the modeling procedure for Korean railway systems and the differences between calcu- lated railway sound levels and measured values obtained using the Schall 03 2012 model. Depending on the location of sound receivers, the difference between the cal- culated and measured values was within approximately 4 dB for various train types. In the case of high-speed trains, the value was approximately 7 dB. A noise-reducing measure was also modeled. The noise reduction effect of a low-height noise barrier system was predicted and evaluated for operating railway sites within the frame- work of a national research project in Korea. The comparison of calculated and measured values showed differences within 2.5 dB.

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