Role of baroclinic currents in bottom salty water formation in the Arkona basin

Abstract Eddy modulation of the air–sea interaction and convection that occurs in the process of mode water formation is analyzed in simulations of a baroclinically unstable wind- and buoyancy-driven jet. The watermass transformation analysis of Walin is used to estimate the formation rate of mode water and to characterize the role of eddies in that process. It is found that diabatic eddy heat flux divergences in the mixed layer are comparable in magnitude, but of opposite sign, to the surface air–sea heat flux and largely cancel the direct effect of buoyancy loss to the atmosphere. The calculations suggest that mode water formation estimates based on climatological air–sea heat flux data and outcrops, which do not fully resolve ocean eddies, may neglect a large opposing term in the heat budget and are thus likely to significantly overestimate true formation rates. In Walin’s watermass transformation framework, this manifests itself as a sensitivity of formation rate estimates to the averaging period over which the outcrops and air–sea fluxes are subjected. The key processes are described in terms of a transformed Eulerian-mean formalism in which eddy-induced mean flow tends to cancel the Eulerian-mean flow, resulting in weaker residual mean flow, subduction, and mode water formation rates.

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A novel assessment of the role of the methyl radical and water formation channel in the CH3OH + H reaction

Physical Chemistry Chemical Physics ◽

10.1039/c7cp03806b ◽

2017 ◽

Vol 19 (36) ◽

pp. 24467-24477 ◽

Cited By ~ 11

Author(s):

Flávio O. Sanches-Neto ◽

Nayara D. Coutinho ◽

Valter H. Carvalho-Silva

Keyword(s):

Atomic Hydrogen ◽

Methyl Radical ◽

Water Formation

A number of experimental and theoretical papers accounted almost exclusively for two channels in the reaction of atomic hydrogen with methanol. However, several astrochemical studies claimed the importance of another channel for this reaction.

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Role of air–sea fluxes and ocean surface density in the production of deep waters in the eastern subpolar gyre of the North Atlantic

Ocean Science ◽

10.5194/os-17-1353-2021 ◽

2021 ◽

Vol 17 (5) ◽

pp. 1353-1365

Author(s):

Tillys Petit ◽

M. Susan Lozier ◽

Simon A. Josey ◽

Stuart A. Cunningham

Keyword(s):

North Atlantic ◽

Surface Density ◽

Ocean Surface ◽

Density Field ◽

The North ◽

Iceland Basin ◽

Deep Waters ◽

Water Formation ◽

Dense Water Formation

Abstract. Wintertime convection in the North Atlantic Ocean is a key component of the global climate as it produces dense waters at high latitudes that flow equatorward as part of the Atlantic Meridional Overturning Circulation (AMOC). Recent work has highlighted the dominant role of the Irminger and Iceland basins in the production of North Atlantic Deep Water. Dense water formation in these basins is mainly explained by buoyancy forcing that transforms surface waters to the deep waters of the AMOC lower limb. Air–sea fluxes and the ocean surface density field are both key determinants of the buoyancy-driven transformation. We analyze these contributions to the transformation in order to better understand the connection between atmospheric forcing and the densification of surface water. More precisely, we study the impact of air–sea fluxes and the ocean surface density field on the transformation of subpolar mode water (SPMW) in the Iceland Basin, a water mass that “pre-conditions” dense water formation downstream. Analyses using 40 years of observations (1980–2019) reveal that the variance in SPMW transformation is mainly influenced by the variance in density at the ocean surface. This surface density is set by a combination of advection, wind-driven upwelling and surface fluxes. Our study shows that the latter explains ∼ 30 % of the variance in outcrop area as expressed by the surface area between the outcropped SPMW isopycnals. The key role of the surface density in SPMW transformation partly explains the unusually large SPMW transformation in winter 2014–2015 over the Iceland Basin.

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KEMISKINAN DI WILAYAH PEDESAAN NTB : STUDI KASUS WANITA PEMBUAT GARAM DI DUSUN MEDANG

Agro Ekonomi ◽

10.22146/agroekonomi.16808 ◽

2016 ◽

Vol 9 (1) ◽

pp. 65

Author(s):

Maryadi Maryadi

Keyword(s):

Sea Water ◽

Salt Water ◽

Poverty Line ◽

Small Scale ◽

Salty Water ◽

Processing Material ◽

Home Industries ◽

Rural Industries ◽

Small Scale Industries

Role of women in development has been well-known. Women roles in rural area can be identified from their involvement in rural industries either agricultural home industries or other small-scale industries processing material taken from natural resources. One of such natural resource materials is sea water to be further processed as salts. Most of women in Medang Hamlet, Village of Sekotong Barat, Nusa Tenggara Barat Province work as salt makers. Instead of drying salty water by using sunshine, the salt farmers in Medang Hamlet use wood in heating the salt water. The study finds that the income earned from this activity is considerably low. Since there is no other source of income alternative for the women in this hamlet, making salt becomes the only job that can be done. The consequence is that the villagers in this area are still live under poverty line.

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Influence of Nordic Seas dynamics on the Atlantic Water propagation and its impacts on sea ice concentration.

10.5194/egusphere-egu21-14798 ◽

2021 ◽

Author(s):

Sourav Chatterjee ◽

Roshin P Raj ◽

Laurent Bertino ◽

Nuncio Murukesh

Keyword(s):

Sea Ice ◽

Deep Water ◽

Atlantic Water ◽

The Arctic ◽

Deep Water Formation ◽

Sea Ice Concentration ◽

Nordic Seas ◽

Ice Concentration ◽

Water Formation

<p>Enhanced intrusion of warm and saline Atlantic Water (AW) to the Arctic Ocean (AO) in recent years has drawn wide interest of the scientific community owing to its potential role in &#8216;Arctic Amplification&#8217;. Not only the AW has warmed over the last few decades , but its transfer efficiency have also undergone significant modifications due to changes in atmosphere and ocean dynamics at regional to large scales. The Nordic Seas (NS), in this regard, play a vital role as the major exchange of polar and sub-polar waters takes place in this region. Further, the AW and its significant modification on its way to AO via the Nordic Seas has large scale implications on e.g., deep water formation, air-sea heat fluxes. Previous studies have suggested that a change in the sub-polar gyre dynamics in the North Atlantic controls the AW anomalies that enter the NS and eventually end up in the AO. However, the role of NS dynamics in resulting in the modifications of these AW anomalies are not well studied. Here in this study, we show that the Nordic Seas are not only a passive conduit of AW anomalies but the ocean circulations in the Nordic Seas, particularly the Greenland Sea Gyre (GSG) circulation can significantly change the AW characteristics between the entry and exit point of AW in the NS. Further, it is shown that the change in GSG circulation can modify the AW heat distribution in the Nordic Seas and can potentially influence the sea ice concentration therein. Projected enhanced atmospheric forcing in the NS in a warming Arctic scenario and the warming trend of the AW can amplify the role of NS circulation in AW propagation and its impact on sea ice, freshwater budget and deep water formation.</p>

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An examination of the role of particles in oceanic mercury cycling

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2015.0297 ◽

2016 ◽

Vol 374 (2081) ◽

pp. 20150297 ◽

Cited By ~ 20

Author(s):

Carl H. Lamborg ◽

Chad R. Hammerschmidt ◽

Katlin L. Bowman

Keyword(s):

Deep Water ◽

Oceanic Water ◽

Deep Water Formation ◽

Mercury Cycling ◽

Trace Element Chemistry ◽

Sinking Particles ◽

Water Formation ◽

Climatic Impacts ◽

Using Data

Recent models of global mercury (Hg) cycling have identified the downward flux of sinking particles in the ocean as a prominent Hg removal process from the ocean. At least one of these models estimates the amount of anthropogenic Hg in the ocean to be about 400 Mmol, with deep water formation and sinking fluxes representing the largest vectors by which pollutant Hg is able to penetrate the ocean interior. Using data from recent cruises to the Atlantic, we examined the dissolved and particulate partitioning of Hg in the oceanic water column as a cross-check on the hypothesis that sinking particle fluxes are important. Interestingly, these new data suggest particle-dissolved partitioning ( K d ) that is approximately 20× greater than previous estimates, which thereby challenges certain assumptions about the scavenging and active partitioning of Hg in the ocean used in earlier models. For example, the new particle data suggest that regenerative scavenging is the most likely mechanism by which the association of Hg and particles occurs. This article is part of the themed issue ‘Biological and climatic impacts of ocean trace element chemistry’.

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Surface and subsurface Labrador Shelf water mass conditions during the last 6000 years

Climate of the Past ◽

10.5194/cp-16-1127-2020 ◽

2020 ◽

Vol 16 (4) ◽

pp. 1127-1143

Author(s):

Annalena A. Lochte ◽

Ralph Schneider ◽

Markus Kienast ◽

Janne Repschläger ◽

Thomas Blanz ◽

...

Keyword(s):

Deep Water ◽

Late Holocene ◽

Thermohaline Circulation ◽

Sea Water ◽

Labrador Sea ◽

Circulation System ◽

Deep Water Formation ◽

Holocene Thermal Maximum ◽

Water Formation

Abstract. The Labrador Sea is important for the modern global thermohaline circulation system through the formation of intermediate Labrador Sea Water (LSW) that has been hypothesized to stabilize the modern mode of North Atlantic deep-water circulation. The rate of LSW formation is controlled by the amount of winter heat loss to the atmosphere, the expanse of freshwater in the convection region and the inflow of saline waters from the Atlantic. The Labrador Sea, today, receives freshwater through the East and West Greenland currents (EGC, WGC) and the Labrador Current (LC). Several studies have suggested the WGC to be the main supplier of freshwater to the Labrador Sea, but the role of the southward flowing LC in Labrador Sea convection is still debated. At the same time, many paleoceanographic reconstructions from the Labrador Shelf focussed on late deglacial to early Holocene meltwater run-off from the Laurentide Ice Sheet (LIS), whereas little information exists about LC variability since the final melting of the LIS about 7000 years ago. In order to enable better assessment of the role of the LC in deep-water formation and its importance for Holocene climate variability in Atlantic Canada, this study presents high-resolution middle to late Holocene records of sea surface and bottom water temperatures, freshening, and sea ice cover on the Labrador Shelf during the last 6000 years. Our records reveal that the LC underwent three major oceanographic phases from the mid- to late Holocene. From 6.2 to 5.6 ka, the LC experienced a cold episode that was followed by warmer conditions between 5.6 and 2.1 ka, possibly associated with the late Holocene thermal maximum. While surface waters on the Labrador Shelf cooled gradually after 3 ka in response to the neoglaciation, Labrador Shelf subsurface or bottom waters show a shift to warmer temperatures after 2.1 ka. Although such an inverse stratification by cooling of surface and warming of subsurface waters on the Labrador Shelf would suggest a diminished convection during the last 2 millennia compared to the mid-Holocene, it remains difficult to assess whether hydrographic conditions in the LC have had a significant impact on Labrador Sea deep-water formation.

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The role of subpolar deep water formation and Nordic Seas overflows in simulated multidecadal variability of the Atlantic meridional overturning circulation

Ocean Science ◽

10.5194/os-10-227-2014 ◽

2014 ◽

Vol 10 (2) ◽

pp. 227-241 ◽

Cited By ~ 19

Author(s):

K. Lohmann ◽

J. H. Jungclaus ◽

D. Matei ◽

J. Mignot ◽

M. Menary ◽

...

Keyword(s):

Deep Water ◽

Atlantic Meridional Overturning Circulation ◽

Meridional Overturning Circulation ◽

Deep Water Formation ◽

Multidecadal Variability ◽

Nordic Seas ◽

Denmark Strait ◽

Water Formation ◽

Meridional Overturning

Abstract. We investigate the respective role of variations in subpolar deep water formation and Nordic Seas overflows for the decadal to multidecadal variability of the Atlantic meridional overturning circulation (AMOC). This is partly done by analysing long (order of 1000 years) control simulations with five coupled climate models. For all models, the maximum influence of variations in subpolar deep water formation is found at about 45° N, while the maximum influence of variations in Nordic Seas overflows is rather found at 55 to 60° N. Regarding the two overflow branches, the influence of variations in the Denmark Strait overflow is, for all models, substantially larger than that of variations in the overflow across the Iceland–Scotland Ridge. The latter might, however, be underestimated, as the models in general do not realistically simulate the flow path of the Iceland–Scotland overflow water south of the Iceland–Scotland Ridge. The influence of variations in subpolar deep water formation is, on multimodel average, larger than that of variations in the Denmark Strait overflow. This is true both at 45° N, where the maximum standard deviation of decadal to multidecadal AMOC variability is located for all but one model, and at the more classical latitude of 30° N. At 30° N, variations in subpolar deep water formation and Denmark Strait overflow explain, on multimodel average, about half and one-third respectively of the decadal to multidecadal AMOC variance. Apart from analysing multimodel control simulations, we have performed sensitivity experiments with one of the models, in which we suppress the variability of either subpolar deep water formation or Nordic Seas overflows. The sensitivity experiments indicate that variations in subpolar deep water formation and Nordic Seas overflows are not completely independent. We further conclude from these experiments that the decadal to multidecadal AMOC variability north of about 50° N is mainly related to variations in Nordic Seas overflows. At 45° N and south of this latitude, variations in both subpolar deep water formation and Nordic Seas overflows contribute to the AMOC variability, with neither of the processes being very dominant compared to the other.

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