Transport processes in the Kara Sea

McClimans, T. A.; Johnson, Donald R.; Krosshavn, M.; King, S.E.; Carroll, JoLynn; Grenness, Ø.

doi:10.1029/1999jc000012

Cited by 29 publications

(36 citation statements)

References 27 publications

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“…Generally, along the outer parts of Arctic Ocean continental margins and across topographic highs in deep basins, sea ice is assumed to be the main contributor seasonal sea-ice formation, ice rafting, peak riverine input shortly after spring break-up, pulsed productivity during ice-free months and increased resuspension of bottom sediments and current transport during ice-free conditions and freeze-up (e.g., Macdonald 2000; McClimans et al 2000; Bauch et al 2001;Sternberg et al 2001; Baskaran et al 2003; Bauch et al 2004;Stein, Schubert et al 2004;Wegner et al 2005). Today, shelf currents experience a strong seasonality with wind and ice as limiting factors (e.g., Harms & Karcher 1999;McClimans et al 2000;Sternberg et al 2001;Wegner et al 2005;Schulze & Pickart 2012).…”

Section: Transport Processesmentioning

confidence: 99%

“…Today, shelf currents experience a strong seasonality with wind and ice as limiting factors (e.g., Harms & Karcher 1999;McClimans et al 2000;Sternberg et al 2001;Wegner et al 2005;Schulze & Pickart 2012). The surface distribution of riverine water and river-derived material shows strong interannual variability, mainly attributed to atmospheric vorticity variations over the adjacent Arctic Ocean in summer (Guay et al 2001;Macdonald et al 2002; ViscosiShirley et al 2003;Dmitrenko et al 2005; Bauch et al 2009;Yamamoto-Kawai et al 2009;Wegner et al 2013).…”

Section: Transport Processesmentioning

confidence: 99%

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Variability in transport of terrigenous material on the shelves and the deep Arctic Ocean during the Holocene

Wegner

Bennett

Vernal³

et al. 2015

Polar Research

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Arctic coastal zones serve as a sensitive filter for terrigenous matter input onto the shelves via river discharge and coastal erosion. This material is further distributed across the Arctic by ocean currents and sea ice. The coastal regions are particularly vulnerable to changes related to recent climate change. We compiled a pan-Arctic review that looks into the changing Holocene sources, transport processes and sinks of terrigenous sediment in the Arctic Ocean. Existing palaeoceanographic studies demonstrate how climate warming and the disappearance of ice sheets during the early Holocene initiated eustatic sea-level rise that greatly modified the physiography of the Arctic Ocean. Sedimentation rates over the shelves and slopes were much greater during periods of rapid sea-level rise in the early and middle Holocene, as a result of the relative distance to the terrestrial sediment sources. However, estimates of suspended sediment delivery through major Arctic rivers do not indicate enhanced delivery during this time, which suggests enhanced rates of coastal erosion. The increased supply of terrigenous material to the outer shelves and deep Arctic Ocean in the early and middle Holocene might serve as analogous to forecast changes in the future Arctic.To access the supplementary material for this article, please see supplementary files under Article Tools online.Rapid changes in the environmental conditions of the Arctic have been observed over recent decades. These include decreasing summer and winter sea-ice extent, increasing annual river discharge, increasing areal extent of open-water areas over the Arctic shelves and lengthening of the open-water season Serreze et al. 2007;Kwok et al. 2009;Wagner et al. 2011;Stroeve et al. 2012;Fichot et al. 2013;Zhang et al. 2013). These changes will likely lead to important transformations in sedimentary environments and the pathways and processes of terrigeneous particulate cycling. In particular, they could play a role in sediment resuspension and coastal erosion (e.g., Atkinson 2005;Eicken et al. 2005; Carmack et al. 2006; Anisimov et al. 2007;Lantuit et al. 2012).The impact of increased export of turbid waters from rivers and coastal regions on Arctic marine ecosystems remains uncertain; it could either increase delivery of nutrients and promote productivity or suppress photosynthesis in the light-limited algal populations by scattering absorbing sunlight (Retamal et al. 2008). An adequate understanding of the pathways of terrigenous material is needed to elucidate connections between sediment and ecosystem dynamics under a changing climate. Research efforts assessing recent trends and variability of terrigenous particulate matter inputs into the Arctic Ocean have been carried out during the past decades and discussed in reviews by Rachold et al. (2004), Macdonald et al. (2010), Forbes (2011) and Goñ i et al. (2013). However, the ability to forecast the future significance of land-derived sedimentary inputs into the Arctic Ocean also needs to account for th...

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Section: Transport Processesmentioning

confidence: 99%

Section: Transport Processesmentioning

confidence: 99%

Variability in transport of terrigenous material on the shelves and the deep Arctic Ocean during the Holocene

Wegner

Bennett

Vernal³

et al. 2015

Polar Research

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“…Another freshwater source is the inflow of Polar Water (T < 6, S < 34.4) into the Barents Sea from the Arctic. The connection between this inflow and wind has been used to force physical laboratory models of the Barents Sea and the Kara Sea (McClimans and Nilsen 1993;McClimans et al 2000). McClimans and Nilsen (1993) used inflow of fresher Polar Water from the north to force the dynamics of the Polar Front in the Barents Sea.…”

Section: Variability Of the Simulated Hydrography And Circulation Of mentioning

confidence: 99%

Modification of water masses in the Barents Sea and its coupling to ice dynamics: a model study

2009

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The physical and biological environment of the Barents Sea is characterised by large variability on a wide range of scales. Results from a numerical ocean model, SINMOD, are presented showing that the physical variability is partly forced by changes in annual net ice import. The mean contribution from ice import in the simulation period is about 40% of the total amount of ice melted each year. The annual ice import into the Barents Sea varies between 143 and 1,236 km 3 , and this causes a substantial variability in the amount of annual ice melt in the Barents Sea. This in turn impacts the freshwater content. The simulated freshwater contribution from ice is 0.02 Sv on average and 0.04 Sv at maximum. When mixed into a mean net Atlantic Water (AW) inflow of 1.1 Sv with a salinity of 35.1, this freshwater addition decreases the salinity of the modified AW to 34.4 and 33.9 for the mean and maximum freshwater fluxes, respectively. Ice import may thus be important for the Barents Sea production of Arctic Ocean halocline water which has salinity of about 34.5. The changes in the ice melt the following summer due to ice import also affect the formation of dense water in the Barents Sea by changing stratification, altering the vertical mixing rates and affecting heat loss from the warm AW. The model results thus indicate that ice import from the Arctic has a great impact on water mass modification in the Barents Sea which in turn impacts the ventilation of the Arctic Ocean.

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“…The strength of the upwelling flow varies as Q 0.3 , with megaplumes (>10 6 L day -1 ) achieving upwelling flows of one or more meters per second (Leifer et al, 2000;Wiggins et al, 2015). In the process, the upwelling flow distorts the flow streamlines associated with currents (McClimans et al, 2000). The upwelling flow carries deeper, cooler (denser) water to shallower depths, doing work against stratification ; however, if the ambient-plume density difference becomes too large, plume fluid detrainment occurs (Aseda and Imberger, 1993), particularly near the thermocline, where water density changes rapidly.…”

Section: Bubble Plumes and Vertical Fluid Motionsmentioning

confidence: 99%

“…Few studies have looked at the interaction between currents, which are absent in lakes, but ubiquitous in the marine setting, and bubbleplume upwelling flows. Currents distort the momentum plume, compressing it in the upstream direction and extending it in the downstream direction (McClimans et al, 2000;Leifer et al, 2009). Detrainment of suspended material from the bubble plume can segregate detritus and upwelled fluids into the downstream momentum plume ) including small, dissolving bubbles (Wilson et al, 2015).…”

Section: Bubble Plumes and Vertical Fluid Motionsmentioning

confidence: 99%

Bubble momentum plume as a possible mechanism for an early breakdown of the seasonal stratification in the northern North Sea

Nauw

Линке

Leifer

2015

Marine and Petroleum Geology

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The presence of a seasonal thermocline likely plays a key role in restraining methane released from a seabed source in the deeper water column, thereby inhibiting exchange to the atmosphere. The bubble plume itself, however, generates an upward motion of fluid, e.g. upwelling and may thereby be partially responsible for an early breakdown of the seasonal thermocline. Measurements at site 22/4b, located at (57 o 55'N, 1 o 38'E) in the UK Central North Sea, 200 km east of the Scottish mainland, where gas is still being released since a blow out in 1990, have been used to identify the generation of the seasonal thermocline, and thus, the depth of the upper mixed layer and its breakdown in autumn. Data derived from two landers, containing an Acoustic Doppler Current Profiler and a Conductivity Temperature Depth recorder, were used to determine the mixed layer depth and the breakdown of the thermocline. Mixing of upper layer fluid into the lower layer has been inferred from large amplitude variations in the near-bottom temperature. The ADCPs estimate velocity profiles in four beam directions using Doppler shifted frequency from acoustic pings sent out and received by four different transducers in a specific configuration. Besides that, the intensity of the backscattered sound per transducer is also recorded. Bubbles from the nearby plume contaminate the signal during part of the tidal cycle, but in bubble free periods, the mixed layer depth can be estimated using the acoustic backscatter signal as local maxima. Results show that the thermocline broke down between mid-October and early November, several weeks earlier than the breakdown of the thermocline in nearby/comparable areas, likely caused by bubble-induced downwelling at the site. The early breakdown of the thermocline was accompanied by multiple occurrence of a strong jet-like structure, associated with the seasonal tidal mixing front. 2

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Transport processes in the Kara Sea

Cited by 29 publications

References 27 publications

Variability in transport of terrigenous material on the shelves and the deep Arctic Ocean during the Holocene

Variability in transport of terrigenous material on the shelves and the deep Arctic Ocean during the Holocene

Modification of water masses in the Barents Sea and its coupling to ice dynamics: a model study

Bubble momentum plume as a possible mechanism for an early breakdown of the seasonal stratification in the northern North Sea

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