Global Analysis of Marine Heatwave physical Processes

2020 ◽  
Author(s):  
Sofia Darmaraki ◽  
Eric Oliver
Keyword(s):  
Algal Blooms ◽  
Heat Budget ◽  
Global Analysis ◽  
Marine Ecosystem ◽  
Global Ocean ◽  
Relative Role ◽  
Physical Processes ◽  
Ocean Reanalysis ◽  
Budget Analysis ◽  
The World

<p>Marine heatwaves (MHWs) are periods of extreme warm temperatures in the ocean and have been seen to exert substantial pressure to marine ecosystems around the world. For instance, they may drive widespread marine species die-offs, force coastal marine ecosystem regime shifts, promote toxic algal blooms, and/or alter the distribution of commercial fisheries on a scale of weeks to months. Recent studies have indicated a significant increase in MHW frequency and intensity throughout the 20<sup>th</sup> century, a trend which is likely to aggravate in the 21<sup>st</sup> century, according to future projections.  Therefore, it is crucial to understand what are the climate drivers and physical processes governing MHWs in different regions of the global ocean and how these may change under the climate change regime. Here, we perform a mixed layer heat budget analysis, using a global ocean reanalysis product, to diagnose the relative role of ocean advection and atmosphere fluxes on the development of past MHWs around the world. Significant events are first identified using a consistent framework. Then, the heat budget results reveal that certain physical processes tend to be dominant in different regions, which can be traced back to specific local-scale dynamics. The global scale of this analysis provides a significant addition to the current literature which has, so far, been focused on the examination of the underlying mechanisms behind individual events. It also contributes to a better understanding of the variability and processes governing MHWs, offering also a potential ability for future event predictability.</p>

scholarly journals Air-to-sea flux of soluble iron: is it driven more by HNO<sub>3</sub> or SO<sub>2</sub>? – an examination in the light of dust aging

2007 ◽  
Vol 7 (4) ◽  
pp. 10043-10063 ◽  
Author(s):  
H. Yang ◽  
Y. Gao
Keyword(s):  
Atmospheric Chemistry ◽  
Transport Model ◽  
World Ocean ◽  
Global Ocean ◽  
Relative Role ◽  
Chemistry Transport Model ◽  
Acidic Gases ◽  
Relative Contribution ◽  
The World

Abstract. Aeolian dust provides the major micronutrient of soluble Fe to organisms in certain regions of the global ocean. In this study, we conduct numerical experiments using the MOZART-2 atmospheric chemistry transport model to simulate the global distribution of soluble Fe flux and Fe solubility. One of the mechanisms behind the hypothesis of acid mobilization of Fe in the atmosphere is that the coating of acidic gases changes dust from hydrophobic to hydrophilic, a prerequisite of Fe mobilization. We therefore include HNO3, SO2 and sulfate (SO42−) as dust transformation agents in the model. General agreement in Fe solubility within a factor of 2 is achieved between model and observations. The total flux of soluble Fe to the world ocean is estimated to be 731–924×109 g yr−1, and the average Fe solubility is 6.4–8.0%. Wet deposition contributes over 80% to total soluble Fe flux to most of the world oceans. Special attention is paid to the relative role of HNO3 versus SO2 and sulfate. We demonstrate that coating by HNO3 produces over 36% of soluble Fe fluxes compared to that by SO2 and sulfate combined in every major oceanic basin. Given present trends in the emissions of NOx and SO2, the relative contribution of HNO3 to Fe mobilization may get even larger in the future.

On the Bias in Simulated ENSO SSTA Meridional Widths of CMIP3 Models

2013 ◽  
Vol 26 (10) ◽  
pp. 3173-3186 ◽  
Author(s):  
Wenjun Zhang ◽  
Fei-Fei Jin ◽  
Jing-Xia Zhao ◽  
Jianping Li
Keyword(s):  
Climate Models ◽  
Southern Oscillation ◽  
Heat Budget ◽  
Coupled Model ◽  
Equatorial Region ◽  
Ocean Reanalysis ◽  
Trade Winds ◽  
Budget Analysis ◽  
Coupled Climate Models ◽  
Damping Rate

Abstract The fidelity of coupled climate models simulating El Niño–Southern Oscillation (ENSO) patterns has been widely examined. Nevertheless, a systematical narrow bias in the simulated meridional width of the sea surface temperature anomaly (SSTA) of ENSO has been largely overlooked. Utilizing the preindustrial control simulations of 11 coupled climate models from phase 3 of the Coupled Model Intercomparison Project (CMIP3), it was shown that the simulated width of the ENSO SSTA is only about two-thirds of what is observed. Through a heat budget analysis based on simulations and ocean reanalysis datasets, it is demonstrated that the SSTA outside of the equatorial strip is predominantly controlled by the anomalous meridional advection by climatological currents and heat-flux damping. The authors thus propose a simple damped-advective conceptual model to describe ENSO width. The simple model indicates that this width is primarily determined by three factors: meridional current, ENSO period, and thermal damping rate. When the meridional current is weak, it spreads the equatorial SSTA away from the equator less effectively and the ENSO width thus tends to be narrow. A short ENSO period allows less time to transport the equatorial SSTA toward the off-equatorial region, and strong damping prevents expansion of the SSTA away from the equator, both of which lead to the meridional width becoming narrow. The narrow bias of the simulated ENSO width is mainly due to a systematical bias in weak trade winds that lead to weak ocean meridional currents, and partly due to a bias toward short ENSO periods.

scholarly journals A global diatom database – abundance, biovolume and biomass in the world ocean

2012 ◽  
Vol 5 (1) ◽  
pp. 147-185 ◽  
Author(s):  
K. Leblanc ◽  
J. Arístegui ◽  
L. Armand ◽  
P. Assmy ◽  
B. Beker ◽  
...  
Keyword(s):  
Marine Ecosystem ◽  
Sampling Site ◽  
World Ocean ◽  
The Arctic ◽  
Global Ocean ◽  
Order Estimate ◽  
Abundance Data ◽  
Marine Ecosystem Model ◽  
The World ◽  
Data Points

Abstract. Phytoplankton identification and abundance data are now commonly feeding plankton distribution databases worldwide. This study is a first attempt to compile the largest possible body of data available from different databases as well as from individual published or unpublished datasets regarding diatom distribution in the world ocean. The data obtained originate from time series studies as well as spatial studies. This effort is supported by the Marine Ecosystem Model Inter-Comparison Project (MAREMIP), which aims at building consistent datasets for the main Plankton Functional Types (PFT) in order to help validate biogeochemical ocean models by using carbon (C) biomass derived from abundance data. In this study we collected over 293 000 individual geo-referenced data points with diatom abundances from bottle and net sampling. Sampling site distribution was not homogeneous, with 58% of data in the Atlantic, 20% in the Arctic, 12% in the Pacific, 8% in the Indian and 1% in the Southern Ocean. A total of 136 different genera and 607 different species were identified after spell checking and name correction. Only a small fraction of these data were also documented for biovolumes and an even smaller fraction was converted to C biomass. As it is virtually impossible to reconstruct everyone's method for biovolume calculation, which is usually not indicated in the datasets, we decided to undertake the effort to document, for every distinct species, the minimum and maximum cell dimensions, and to convert all the available abundance data into biovolumes and C biomass using a single standardized method. Statistical correction of the database was also adopted to exclude potential outliers and suspicious data points. The final database contains 90 648 data points with converted C biomass. Diatom C biomass calculated from cell sizes spans over eight orders of magnitude. The mean diatom biomass for individual locations, dates and depths is 141.19 μg C l−1, while the median value is 11.16 μg C l−1. Regarding biomass distribution, 19% of data are in the range 0–1 μg C l−1, 29% in the range 1–10 μg C l−1, 31% in the range 10–100 μg C l−1, 18% in the range 100–1000 μg C l−1, and only 3% >1000 μg C l−1. Interestingly, less than 50 species contributed to >90% of global biomass, among which centric species were dominant. Thus, placing significant efforts on cell size measurements, process studies and C quota calculations on these species should considerably improve biomass estimates in the upcoming years. A first-order estimate of the diatom biomass for the global ocean ranges from 449 to 558 Tg C, which converts to 5 to 6 Tmol Si and to an average Si biomass turnover rate of 0.11 to 0.20 d−1. Link to the dataset: preliminary link http://doi.pangaea.de/10.1594/PANGAEA.777384.

scholarly journals Drivers of Local Ocean Heat Content Variability in ECCOv4

2021 ◽  
pp. 1-51
Author(s):  
Jan-Erik Tesdal ◽  
Ryan P. Abernathey
Keyword(s):  
Heat Budget ◽  
Global Climate ◽  
Heat Content ◽  
Ocean Heat Content ◽  
Global Ocean ◽  
Western Boundary ◽  
Budget Analysis ◽  
Dynamical Regimes ◽  
Temporal And Spatial ◽  
The Tropics

AbstractVariation in upper ocean heat content is a critical factor in understanding global climate variability. Using temperature anomaly budgets in a two-decade-long physically consistent ocean state estimate (ECCOv4r3, 1992-2015), we describe the balance between atmospheric forcing and ocean transport mechanisms for different depth horizons and at varying temporal and spatial resolutions. Advection dominates in the tropics, while forcing is most relevant at higher latitudes and in parts of the subtropics, but the balance of dominant processes changes when integrating over greater depths and considering longer time scales. While forcing is shown to increase with coarser resolution, overall the heat budget balance between it and advection is remarkably insensitive to spatial scale. A novel perspective on global ocean heat content variability was made possible by combining unsupervised classification with a measure of temporal variability in heat budget terms to identify coherent dynamical regimes with similar underlying mechanisms, which are consistent with prior research. The vast majority of the ocean includes significant contributions by both forcing and advection. However advection-driven regions were identified that coincide with strong currents, such as western boundary currents, the Antarctic Circumpolar Current and the tropics, while forcing-driven regions were defined by shallower wintertime mixed layers and weak velocity fields. This identification of comprehensive dynamical regimes and the sensitivity of the ocean heat budget analysis to exact resolution (for different depth horizons and at varying temporal and spatial resolutions) should provide a useful orientation for future studies of ocean heat content variability in specific ocean regions.

scholarly journals A global diatom database – abundance, biovolume and biomass in the world ocean

2012 ◽  
Vol 4 (1) ◽  
pp. 149-165 ◽  
Author(s):  
K. Leblanc ◽  
J. Arístegui ◽  
L. Armand ◽  
P. Assmy ◽  
B. Beker ◽  
...  
Keyword(s):  
Marine Ecosystem ◽  
Sampling Site ◽  
World Ocean ◽  
The Arctic ◽  
Global Ocean ◽  
Order Estimate ◽  
Abundance Data ◽  
Marine Ecosystem Model ◽  
The World ◽  
Data Points

Abstract. Phytoplankton identification and abundance data are now commonly feeding plankton distribution databases worldwide. This study is a first attempt to compile the largest possible body of data available from different databases as well as from individual published or unpublished datasets regarding diatom distribution in the world ocean. The data obtained originate from time series studies as well as spatial studies. This effort is supported by the Marine Ecosystem Model Inter-Comparison Project (MAREMIP), which aims at building consistent datasets for the main plankton functional types (PFTs) in order to help validate biogeochemical ocean models by using carbon (C) biomass derived from abundance data. In this study we collected over 293 000 individual geo-referenced data points with diatom abundances from bottle and net sampling. Sampling site distribution was not homogeneous, with 58% of data in the Atlantic, 20% in the Arctic, 12% in the Pacific, 8% in the Indian and 1% in the Southern Ocean. A total of 136 different genera and 607 different species were identified after spell checking and name correction. Only a small fraction of these data were also documented for biovolumes and an even smaller fraction was converted to C biomass. As it is virtually impossible to reconstruct everyone's method for biovolume calculation, which is usually not indicated in the datasets, we decided to undertake the effort to document, for every distinct species, the minimum and maximum cell dimensions, and to convert all the available abundance data into biovolumes and C biomass using a single standardized method. Statistical correction of the database was also adopted to exclude potential outliers and suspicious data points. The final database contains 90 648 data points with converted C biomass. Diatom C biomass calculated from cell sizes spans over eight orders of magnitude. The mean diatom biomass for individual locations, dates and depths is 141.19 μg C l−1, while the median value is 11.16 μg C l−1. Regarding biomass distribution, 19% of data are in the range 0–1 μg C l−1, 29% in the range 1–10 μg C l−1, 31% in the range 10–100 μg C l−1, 18% in the range 100–1000 μg C l−1, and only 3% > 1000 μg C l−1. Interestingly, less than 50 species contributed to > 90% of global biomass, among which centric species were dominant. Thus, placing significant efforts on cell size measurements, process studies and C quota calculations of these species should considerably improve biomass estimates in the upcoming years. A first-order estimate of the diatom biomass for the global ocean ranges from 444 to 582 Tg C, which converts to 3 to 4 Tmol Si and to an average Si biomass turnover rate of 0.15 to 0.19 d−1. Link to the dataset: doi:10.1594/PANGAEA.777384.

scholarly journals Trends and Evolution in the Concept of Marine Ecosystem Services: An Overview

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2060
Author(s):  
Elvira Buonocore ◽  
Umberto Grande ◽  
Pier Paolo Franzese ◽  
Giovanni F. Russo
Keyword(s):  
Ecosystem Services ◽  
Alternative Assessment ◽  
Natural Capital ◽  
Marine Ecosystem ◽  
Management Strategies ◽  
Marine Ecosystems ◽  
Global Ocean ◽  
Coastal Protection ◽  
Policy Dialogue ◽  
Marine Ecosystem Services

The biotic and abiotic assets of the marine environment form the “marine natural capital” embedded in the global ocean. Marine natural capital provides the flow of “marine ecosystem services” that are directly used or enjoyed by people providing benefits to human well-being. They include provisioning services (e.g., food), regulation and maintenance services (e.g., carbon sequestration and storage, and coastal protection), and cultural services (e.g., tourism and recreational benefits). In recent decades, human activities have increased the pressures on marine ecosystems, often leading to ecosystem degradation and biodiversity loss and, in turn, affecting their ability to provide benefits to humans. Therefore, effective management strategies are crucial to the conservation of healthy and diverse marine ecosystems and to ensuring their long-term generation of goods and services. Biophysical, economic, and sociocultural assessments of marine ecosystem services are much needed to convey the importance of natural resources to managers and policy makers supporting the development and implementation of policies oriented for the sustainable management of marine resources. In addition, the accounting of marine ecosystem service values can be usefully complemented by their mapping to enable the identification of priority areas and management strategies and to facilitate science–policy dialogue. Given this premise, this study aims to review trends and evolution in the concept of marine ecosystem services. In particular, the global scientific literature on marine ecosystem services is explored by focusing on the following main aspects: the definition and classification of marine ecosystem services; their loss due to anthropogenic pressures, alternative assessment, and mapping approaches; and the inclusion of marine ecosystem services into policy and decision-making processes.

scholarly journals Do CMIP5 Models Show El Niño Diversity?

2020 ◽  
Vol 33 (5) ◽  
pp. 1619-1641 ◽  
Author(s):  
Jie Feng ◽  
Tao Lian ◽  
Jun Ying ◽  
Junde Li ◽  
Gen Li
Keyword(s):  
El Niño ◽  
El Nino ◽  
Heat Budget ◽  
Equatorial Pacific ◽  
Cmip5 Models ◽  
Budget Analysis ◽  
Future Global Warming ◽  
Central Equatorial Pacific ◽  
The Future ◽  
Sst Gradient

AbstractWhether the state-of-the-art CMIP5 models have different El Niño types and how the degree of modeled El Niño diversity would be impacted by the future global warming are still heavily debated. In this study, cluster analysis is used to investigate El Niño diversity in 30 CMIP5 models. As the method does not rely on any prior knowledge of the patterns of El Niño seen in observations, it provides a practical way to identify the degree of El Niño diversity in models. Under the historical scenario, most models show a poor degree of El Niño diversity in their own model world, primarily due to the lopsided numbers of events belonging to the two modeled El Niño types and the weak compactness of events in each cluster. Four models are found showing significant El Niño diversity, yet none of them captures the longitudinal distributions of the warming centers of the two El Niño types seen in the observations. Heat budget analysis of the sea surface temperature (SST) anomaly suggests that the degree of modeled El Niño diversity is highly related to the climatological zonal SST gradient over the western-central equatorial Pacific in models. As the gradient is weakened in most models under the future high-emission scenario, the degree of modeled El Niño diversity is further reduced in the future. The results indicate that a better simulation of the SST gradient over the western-central equatorial Pacific might allow a more reliable simulation/projection of El Niño diversity in most CMIP5 models.

Effects of light and phosphorus on summer DMS dynamics in subtropical waters using a global ocean biogeochemical model

2016 ◽  
Vol 13 (2) ◽  
pp. 379 ◽  
Author(s):  
Italo Masotti ◽  
Sauveur Belviso ◽  
Laurent Bopp ◽  
Alessandro Tagliabue ◽  
Eva Bucciarelli
Keyword(s):  
General Circulation ◽  
North Atlantic Ocean ◽  
Model Simulation ◽  
Global Ocean ◽  
Longitudinal Distribution ◽  
Biogeochemical Model ◽  
Relative Role ◽  
Sargasso Sea ◽  
Ecological Processes ◽  
Climatological Data

Environmental context Models are needed to predict the importance of the changes in marine emissions of dimethylsulfide (DMS) in response to ocean warming, increased stratification and acidification, and to evaluate the potential effects on the Earth’s climate. We use complementary simulations to further our understanding of the marine cycle of DMS in subtropical waters, and show that a lack of phosphorus may exert a more important control on surface DMS concentrations than an excess of light. Abstract The occurrence of a summer DMS paradox in the vast subtropical gyres is a strong matter of debate because approaches using discrete measurements, climatological data and model simulations yielded contradictory results. The major conclusion of the first appraisal of prognostic ocean DMS models was that such models need to give more weight to the direct effect of environmental forcings (e.g. irradiance) on DMS dynamics to decouple them from ecological processes. Here, the relative role of light and phosphorus on summer DMS dynamics in subtropical waters is assessed using the ocean general circulation and biogeochemistry model NEMO-PISCES in which macronutrient concentrations were restored to monthly climatological data values to improve the representation of phosphate concentrations. Results show that the vertical and temporal decoupling between chlorophyll and DMS concentrations observed in the Sargasso Sea during the summer months is captured by the model. Additional sensitivity tests show that the simulated control of phosphorus on surface DMS concentrations in the Sargasso Sea is much more important than that of light. By extending the analysis to the whole North Atlantic Ocean, we show that the longitudinal distribution of DMS during summer is asymmetrical and that a correlation between the solar radiation dose and DMS concentrations only occurs in the Sargasso Sea. The lack of a widespread summer DMS paradox in our model simulation as well as in the comparison of discrete and climatological data could be due to the limited occurrence of phosphorus limitation in the global ocean.

scholarly journals MAREDAT: towards a World Ocean Atlas of MARine Ecosystem DATa

2012 ◽  
Vol 5 (2) ◽  
pp. 1077-1106 ◽  
Author(s):  
E. T. Buitenhuis ◽  
M. Vogt ◽  
R. Moriarty ◽  
N. Bednaršek ◽  
S. C. Doney ◽  
...  
Keyword(s):  
Marine Ecosystem ◽  
World Ocean ◽  
Zooplankton Biomass ◽  
Global Ocean ◽  
Special Issue ◽  
Biomass Distribution ◽  
Phytoplankton Pigment ◽  
Autotrophic Biomass ◽  
Ocean Ecosystem ◽  
World Ocean Atlas

Abstract. We present a summary of biomass data for 11 Plankton Functional Types (PFTs) plus phytoplankton pigment data, compiled as part of the MARine Ecosystem biomass DATa (MAREDAT) initiative. The goal of the MAREDAT initiative is to provide global gridded data products with coverage of all biological components of the global ocean ecosystem. This special issue is the first step towards achieving this. The PFTs presented here include picophytoplankton, diazotrophs, coccolithophores, Phaeocystis, diatoms, picoheterotrophs, microzooplankton, foraminifers, mesozooplankton, pteropods and macrozooplankton. All variables have been gridded onto a World Ocean Atlas (WOA) grid (1° × 1° × 33 vertical levels × monthly climatologies). The data show that (1) the global total heterotrophic biomass (2.0–6.4 Pg C) is at least as high as the total autotrophic biomass (0.5–2.6 Pg C excluding nanophytoplankton and autotrophic dinoflagellates), (2) the biomass of zooplankton calcifiers (0.9–2.3 Pg C) is substantially higher than that of coccolithophores (0.01–0.14 Pg C), (3) patchiness of biomass distribution increases with organism size, and (4) although zooplankton biomass measurements below 200 m are rare, the limited measurements available suggest that Bacteria and Archaea are not the only heterotrophs in the deep sea. More data will be needed to characterize ocean ecosystem functioning and associated biogeochemistry in the Southern Hemisphere and below 200 m. Microzooplankton database: doi:10.1594/PANGAEA.779970.

Arrighi’s Theory of systemic cycles of capital accumulation as a mechanism of cyclical development of the Global Economy

2021 ◽  
pp. 966-981
Author(s):  
Sergey Gennadyevich Kapkanshchikov
Keyword(s):  
Capital Accumulation ◽  
World Economy ◽  
Global Analysis ◽  
Methodological Approach ◽  
The United States ◽  
State Regulation ◽  
Economic Order ◽  
The World ◽  
World Economic ◽  
World Economic Order

The article uses the methodology of systemic global analysis and the theory of systemic cycles of capital accumulation to argue that we are now at a turning point of the modern era in connection with the unfolding change in the dominant world economic order. Based on the methodological approach, within the framework of which there is a hegemonic country and the rest of the world, the forecast regarding the forthcoming multipolarity of the world economy is rejected. Various stages of capital and financial expansion with their inherent, respectively, dirigistic and liberal models of state regulation of the economy are compared to each other. A chronological overview of the Spanish-Genoese, Dutch, British, American and Asian accumulation cycles is presented. The patterns of their change in the course of the formation of new technological structures are revealed. The place of Russia in the process of natural evolution of world economic structures is also identified. The objective and subjective reasons for the longterm hegemony of the United States, as well as factors of the upcoming completion of the American cycle of capital accumulation in the foreseeable future, are revealed. The author outlines the tactics employed by the American authorities to counteract the objective hegemonic cycles. The reasons for the movement of the center of the world economy to the East Asian region are revealed, with the justification of the need for a natural inclusion of Russia in the functioning of the Asian world economic order.

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