scholarly journals Impact of episodic vertical fluxes on sea surface pCO 2

2011 ◽  
Vol 369 (1943) ◽  
pp. 2009-2025 ◽  
Author(s):  
A. Mahadevan ◽  
A. Tagliabue ◽  
L. Bopp ◽  
A. Lenton ◽  
L. Mémery ◽  
...  
Keyword(s):  
Dissolved Inorganic Carbon ◽  
Vertical Mixing ◽  
Analytical Framework ◽  
Relative Magnitude ◽  
Sea Surface ◽  
Surface Mixed Layer ◽  
Episodic Events ◽  
Subsurface Waters ◽  
The Individual ◽  
Episodic Mixing

Episodic events like hurricanes, storms and frontal- and eddy-driven upwelling can alter the partial pressure of CO 2 (pCO 2 ) at the sea surface by entraining subsurface waters into the surface mixed layer (ML) of the ocean. Since pCO 2 is a function of total dissolved inorganic carbon (DIC), temperature ( T ), salinity and alkalinity, it responds to the combined impacts of physical, chemical and biological changes. Here, we present an analytical framework for assessing the relative magnitude and sign in the short-term perturbation of surface pCO 2 arising from vertical mixing events. Using global, monthly, climatological datasets, we assess the individual, as well as integrated, contribution of various properties to surface pCO 2 in response to episodic mixing. The response depends on the relative vertical gradients of properties beneath the ML. Many areas of the ocean exhibit very little sensitivity to mixing owing to the compensatory effects of DIC and T on pCO 2 , whereas others, such as the eastern upwelling margins, have the potential to generate large positive/negative anomalies in surface pCO 2 . The response varies seasonally and spatially and becomes more intense in subtropical and subpolar regions during summer. Regions showing a greater pCO 2 response to vertical mixing are likely to exhibit higher spatial variability in surface pCO 2 on time scales of days.

scholarly journals Fluxes of carbon and nutrients to the Iceland Sea surface layer and inferred primary productivity and stoichiometry

2014 ◽  
Vol 11 (11) ◽  
pp. 15399-15433
Author(s):  
E. Jeansson ◽  
R. G. J. Bellerby ◽  
I. Skjelvan ◽  
H. Frigstad ◽  
S. R. Ólafsdóttir ◽  
...  
Keyword(s):  
Surface Layer ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Vertical Mixing ◽  
Sea Surface ◽  
Net Community Production ◽  
Horizontal Advection ◽  
Vertical Fluxes ◽  
Biological Uptake ◽  
Community Production

Abstract. Fluxes of carbon and nutrients to the upper 100 m of the Iceland Sea are evaluated. The study utilises hydro-chemical data from the Iceland Sea time-series station (68.00° N, 12.67° W), for the years between 1993 and 2006. By comparing data of dissolved inorganic carbon (DIC) and nutrients in the surface layer (upper 100 m), and a sub-surface layer (100–200 m), we calculate monthly deficits in the surface, and use these to deduce the surface layer fluxes that affect the deficits: vertical mixing, horizontal advection, air–sea exchange, and biological activity. The deficits show a clear seasonality with a minimum in winter, when the mixed layer is at the deepest, and a maximum in early autumn, when biological uptake has removed much of the nutrients. The annual vertical fluxes of DIC and nitrate amounts to 1.7 ± 0.3 and 0.23 ± 0.07 mol m−2 yr−1, respectively, and the annual air–sea uptake of atmospheric CO2 is 4.4 ± 1.1 mol m−2 yr−1. The biologically driven changes in DIC during the year relates to net community production (NCP), and the net annual NCP corresponds to export production, and is here calculated to 6.1 ± 0.9 mol C m−2 yr−1. The typical, median C : N ratio during the period of net community uptake is 11, and thus clearly higher than Redfield, but is varying during the season.

scholarly journals Southern Ocean heat storage, reemergence, and winter sea ice decline induced by summertime winds

2020 ◽  
pp. 1-47
Author(s):  
Edward W. Doddridge ◽  
John Marshall ◽  
Hajoon Song ◽  
Jean-Michel Campin ◽  
Maxwell Kelley
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Mixed Layer ◽  
Vertical Mixing ◽  
Heat Content ◽  
Ice Cover ◽  
Sea Surface ◽  
Surface Mixed Layer ◽  
Surface Cooling ◽  
Westerly Winds

AbstractThe observational record shows a substantial 40-year upward trend in summertime westerly winds over the Southern Ocean, as characterised by the Southern Annular Mode (SAM) index. Enhanced summertime westerly winds have been linked to cold summertime sea surface temperature (SST) anomalies. Previous studies have suggested that Ekman transport or upwelling is responsible for this seasonal cooling. Here, another process is presented in which enhanced vertical mixing, driven by summertime wind anomalies, moves heat downwards, cooling the sea surface and simultaneously warming the subsurface waters. The anomalously cold SSTs draw heat from the atmosphere into the ocean, leading to increased depth-integrated ocean heat content. The subsurface heat is returned to the surface mixed layer during the autumn and winter as the mixed layer deepens, leading to anomalously warm SSTs and potentially reducing sea ice cover. Observational analyses and numerical experiments support our proposed mechanism, showing that enhanced vertical mixing produces subsurface warming and cools the surface mixed layer. Nevertheless, the dominant driver of surface cooling remains uncertain; the relative importance of advective and mixing contributions to the surface cooling is model dependent. Modeling results suggest that sea ice volume is more sensitive to summertime winds than sea ice extent, implying that enhanced summertime westerly winds may lead to thinner sea ice in the following winter, if not lesser ice extent. Thus, strong summertime winds could precondition the sea ice cover for a rapid retreat in the following melt season.

scholarly journals Fluxes of carbon and nutrients to the Iceland Sea surface layer and inferred primary productivity and stoichiometry

2015 ◽  
Vol 12 (3) ◽  
pp. 875-885 ◽  
Author(s):  
E. Jeansson ◽  
R. G. J. Bellerby ◽  
I. Skjelvan ◽  
H. Frigstad ◽  
S. R. Ólafsdóttir ◽  
...  
Keyword(s):  
Surface Layer ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Vertical Mixing ◽  
Sea Surface ◽  
Net Community Production ◽  
Horizontal Advection ◽  
Vertical Fluxes ◽  
Community Production

Abstract. This study evaluates long-term mean fluxes of carbon and nutrients to the upper 100 m of the Iceland Sea. The study utilises hydro-chemical data from the Iceland Sea time series station (68.00° N, 12.67° W), for the years between 1993 and 2006. By comparing data of dissolved inorganic carbon (DIC) and nutrients in the surface layer (upper 100 m), and a sub-surface layer (100–200 m), we calculate monthly deficits in the surface, and use these to deduce the long-term mean surface layer fluxes that affect the deficits: vertical mixing, horizontal advection, air–sea exchange, and biological activity. The deficits show a clear seasonality with a minimum in winter, when the mixed layer is at the deepest, and a maximum in early autumn, when biological uptake has removed much of the nutrients. The annual vertical fluxes of DIC and nitrate amounts to 2.9 ± 0.5 and 0.45 ± 0.09 mol m−2 yr−1, respectively, and the annual air–sea uptake of atmospheric CO2 is 4.4 ± 1.1 mol C m−2 yr−1. The biologically driven changes in DIC during the year relates to net community production (NCP), and the net annual NCP corresponds to export production, and is here calculated as 7.3 ± 1.0 mol C m−2 yr−1. The typical, median C : N ratio during the period of net community uptake is 9.0, and clearly higher than the Redfield ratio, but is varying during the season.

Academic Events: An Empirically Grounded Typology and Their Academic Impact

2020 ◽  
Vol 24 (4) ◽  
pp. 481-497 ◽  
Author(s):  
Thomas Trøst Hansen ◽  
David Budtz Pedersen ◽  
Carmel Foley
Keyword(s):  
Analytical Framework ◽  
Future Research ◽  
Academic Impact ◽  
Future Research Agenda ◽  
Tourism Studies ◽  
Academic Events ◽  
Business Events ◽  
The Individual ◽  
Analytical Frameworks ◽  
Academic Sector

The meetings industry, government bodies, and scholars within tourism studies have identified the need to understand the broader impact of business events. To succeed in this endeavor, we consider it necessary to develop analytical frameworks that are sensitive to the particularities of the analyzed event, sector, and stakeholder group. In this article we focus on the academic sector and offer two connected analyses. First is an empirically grounded typology of academic events. We identify four differentiating dimensions of academic events: size, academic focus, participants, and tradition, and based on these dimensions we develop a typology of academic events that includes: congress, specialty conference, symposium, and practitioners' meeting. Secondly, we outline the academic impact of attending these four types of events. For this purpose, the concept of credibility cycles is used as an analytical framework for examining academic impact. We suggest that academic events should be conceptualized and evaluated as open marketplaces that facilitate conversion of credibility. Data were obtained from interviews with 22 researchers at three Danish universities. The study concludes that there are significant differences between the events in terms of their academic impact. Moreover, the outcome for the individual scholar depends on the investment being made. Finally, the study calls for a future research agenda on beyond tourism benefits based on interdisciplinary collaborations.

scholarly journals A SIGHT OVER THE HEALTH OF WASTE PICKERS: AN ANALYTICAL FRAMEWORK PROPOSITION

2018 ◽  
Vol 21 (0) ◽  
Author(s):  
LAYSCE ROCHA DE MOURA ◽  
SYLMARA LOPES FRANCELINO GONÇALVES DIAS ◽  
LUCIANO ANTONIO PRATES JUNQUEIRA
Keyword(s):  
Systematic Review ◽  
Empirical Studies ◽  
Analytical Framework ◽  
Review Of Literature ◽  
Individual Activity ◽  
The Individual ◽  
Waste Pickers

Abstract This study aims to identify articles focused on the waste picker’s health to support the construction of an analytical framework that considers the individual and the environment in the scope of their labor activity. For this purpose, it is intended to answer the following question: which aspects can be considered in the analysis of the waste picker’s health in their labor activity? Methodologically, it has an exploratory nature and use the Systematic Review of Literature. The results pointed out to four categories of analysis grouped into the following aspects: meanings, individual, activity and environment. The analytical framework proposed presents contributions for an extended understanding of waste picker’s health, its aspects and interrelationships. Finally, it is suggested that empirical studies could be carried out to validate the proposed structure.

scholarly journals SST Anomalies in the Mozambique Channel Using Remote Sensing and Numerical Modeling Data

2019 ◽  
Vol 11 (9) ◽  
pp. 1112
Author(s):  
Guoqing Han ◽  
Changming Dong ◽  
Junde Li ◽  
Jingsong Yang ◽  
Qingyue Wang ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Mixed Layer Depth ◽  
Surface Wind ◽  
Radiant Heat ◽  
Heat Fluxes ◽  
Sea Surface ◽  
Surface Mixed Layer ◽  
Mozambique Channel ◽  
Sea Surface Wind ◽  
Sst Anomalies

Based on both satellite remote sensing sea surface temperature (SST) data and numerical model results, SST warming differences in the Mozambique Channel (MC) west of the Madagascar Island (MI) were found with respect to the SST east of the MI along the same latitude. The mean SST west of the MI is up to about 3.0 °C warmer than that east of the MI. The SST differences exist all year round and the maximum value appears in October. The area of the highest SST is located in the northern part of the MC. Potential factors causing the SST anomalies could be sea surface wind, heat flux and oceanic flow advection. The presence of the MI results in weakening wind in the MC and in turn causes weakening of the mixing in the upper oceans, thus the surface mixed layer depth becomes shallower. There is more precipitation on the east of the MI than that inside the MC because of the orographic effects. Different precipitation patterns and types of clouds result in different solar radiant heat fluxes across both sides of the MI. Warm water advected from the equatorial area also contribute to the SST warm anomalies.

scholarly journals Interannual Variability of Sea Surface Temperature off Java and Sumatra in a Global GCM*

2008 ◽  
Vol 21 (11) ◽  
pp. 2451-2465 ◽  
Author(s):  
Yan Du ◽  
Tangdong Qu ◽  
Gary Meyers
Keyword(s):  
Indian Ocean ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Mixed Layer ◽  
Heat Budget ◽  
Sea Surface ◽  
Surface Mixed Layer ◽  
Horizontal Advection ◽  
Cold Anomaly ◽  
Sst Anomalies

Abstract Using results from the Simple Ocean Data Assimilation (SODA), this study assesses the mixed layer heat budget to identify the mechanisms that control the interannual variation of sea surface temperature (SST) off Java and Sumatra. The analysis indicates that during the positive Indian Ocean Dipole (IOD) years, cold SST anomalies are phase locked with the season cycle. They may exceed −3°C near the coast of Sumatra and extend as far westward as 80°E along the equator. The depth of the thermocline has a prominent influence on the generation and maintenance of SST anomalies. In the normal years, cooling by upwelling–entrainment is largely counterbalanced by warming due to horizontal advection. In the cooling episode of IOD events, coastal upwelling–entrainment is enhanced, and as a result of mixed layer shoaling, the barrier layer no longer exists, so that the effect of upwelling–entrainment can easily reach the surface mixed layer. Horizontal advection spreads the cold anomaly to the interior tropical Indian Ocean. Near the coast of Java, the northern branch of an anomalous anticyclonic circulation spreads the cold anomaly to the west near the equator. Both the anomalous advection and the enhanced, wind-driven upwelling generate the cold SST anomaly of the positive IOD. At the end of the cooling episode, the enhanced surface thermal forcing overbalances the cooling effect by upwelling/entrainment, and leads to a warming in SST off Java and Sumatra.

scholarly journals Particulate organic carbon (POC) in relation to other pore water carbon fractions in drained and rewetted fens in Southern Germany

2008 ◽  
Vol 5 (6) ◽  
pp. 1615-1623 ◽  
Author(s):  
S. Fiedler ◽  
B. S. Höll ◽  
A. Freibauer ◽  
K. Stahr ◽  
M. Drösler ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Particulate Organic Carbon ◽  
Pore Water ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Relative Importance ◽  
Pore Waters ◽  
Calcareous Fens ◽  
Essential Components ◽  
The Individual

Abstract. Numerous studies have dealt with carbon (C) contents in Histosols, but there are no studies quantifying the relative importance of the individual C components in pore waters. For this study, measurements were taken of all the carbon components (particulate organic carbon, POC; dissolved organic carbon, DOC; dissolved inorganic carbon, DIC; dissolved methane, CH4) in the soil pore water of calcareous fens under three different water management regimes (re-wetted, deeply and moderately drained). Pore water was collected weekly or biweekly (April 2004 to April 2006) at depths between 10 and 150 cm. The main results obtained were: (1) DIC (94–280 mg C l−1) was the main C-component. (2) POC and DOC concentrations in the pore water (14–125 mg C l−1 vs. 41–95 mg C l−1) were pari passu. (3) Dissolved CH4 was the smallest C component (0.005–0.9 mg C l−1). Interestingly, about 30% of the POM particles were colonized by microbes indicating that they are active in the internal C turnover. Certainly, both POC and DOC fractions are essential components of the C budget of peatlands. Furthermore, dissolved CO2 in all forms of DIC appears to be an important part of peatland C-balance.

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