Percentage contribution of inputs from the Atlantic, Irish Sea, English Channel and Baltic into the North Sea during 1988: A tracer-based evaluation using artificial radionuclides

Bois, Pascal Bailly du; Guegueniat, P.; Gandon, R.; León, Ricardo; Baron, Y.

doi:10.1016/0077-7579(93)90012-h

Cited by 24 publications

(13 citation statements)

References 12 publications

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“…waters from northern inflow regions and Channel waters) to the steady-state water mass distribution over the model grid. The results could be reasonably well compared to similar quantities derived from observations of radionuclides and salinity in the summer of 1988 (Bailly du Bois et al 1993). For further detail on these validation studies see Kerkhoven (2000).…”

Section: Model Descriptionsupporting

confidence: 54%

Large-scale circulation and flushing characteristics of the North Sea under various climate forcings

Blaas

Kerkhoven²,

Swart³

2001

Clim. Res.

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With the aid of a numerical model it is shown that, in addition to the residual effects of tides and winds, the meridional density distribution in the North-East Atlantic Ocean has a significant effect on the large-scale, residual circulation in the North Sea. This effect is due to the fact that the currents along the continental slope, which are mainly forced by density gradients and tides, intrude into the deeper parts of the shelf sea and, as a consequence, oppose or enhance the wind-driven circulation. From dispersion-model experiments it is demonstrated that the interplay of the tide, ocean density, and winds results in efficient flushing of the basin if their effects coincide. However, the residual circulation may break up into closed cells on the shelf if forcings counteract. In that case, efficient renewal of material is inhibited. The characteristics of the dispersion of material in the shelf sea are quantified by computing the spatial distributions of residence times. In addition, basin-wide flushing characteristics are typified by calculating turn-over and flushing time scales. The ratio of these time scales is used as a measure for the relative retention strength of material within the basin by closed circulation cells.

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Section: Model Descriptionsupporting

confidence: 54%

Large-scale circulation and flushing characteristics of the North Sea under various climate forcings

Blaas

Kerkhoven²,

Swart³

2001

Clim. Res.

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“…Antimony 125, nearly absent from other sources and conservative in seawater, is the reference marker to identify the water plume labelled by the La Hague plant. It clearly shows the dispersion of these releases in the English Channel and the North Sea Guéguéniat et al, 1993 ;Guéguéniat et al, 1994 ;Bailly du Bois et al, 1993 ;Bailly du Bois et al, 1995).…”

Section: Radiolabelling From La Haguementioning

confidence: 91%

Quantitative assessment of dissolved radiotracers in the English Channel: Sources, average impact of la Hague reprocessing plant and conservative behaviour (1983, 1986, 1988, 1994)

Bois

Guegueniat²

1999

Continental Shelf Research

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Knowledge of long-term movements of water-masses in the English Channel has been substantially improved using hydrodynamic modelling coupled with radio-tracers studies ; nevertheless, the precision of results so obtained is still largely dependent on measurement precision.New tools are now available to make more accurate determinations of radio-tracer distribution : -Repositioning of station locations at the same tide reference-time, giving a homogeneous spatial data set, coupled with the possibility of interpolating and quantifying the amounts of dissolved radioactivity flowing through the English Channel ;-The first measurements of tritium ( 3 H) in seawater on a large scale in the English Channel demonstrate that this fully conservative radionuclide is a clearly identifiable marker of industrial releases ;-Recent campaigns carried out during the FluxManche II CCE (1994) programme show the general distribution of dissolved radionuclides 137 Cs, 134 Cs, 60 Co, 125 Sb, 106 Ru and 3 H in the English Channel and the Irish Sea ;-The re-utilisation of data from previous campaigns (1983, 1986 and 1988) provides indications, at any given location in the English Channel, about the average dilution and distribution of releases derived from the La Hague reprocessing plant.Excesses and losses of radionuclides are now quantified with respect to known source-terms ; estimates of losses are provided for non-conservative radionuclides, while an excess of 137 Cs was observed in the English Channel during the period 1983 -1994. This excess which has the same order of magnitude as the quantities released from La Hague plant in the English Channel, could be explained by about 1% of Sellafield reprocessing plant releases entering the Channel.These results confirm and give a more detailed picture of the previously known distribution of water masses in the English Channel. They lead to clear information about transit times and dilution at this scale, and provide directly comparable data for the validation of hydrodynamic models.

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“…produced during the period of atmospheric nuclear bomb tests provided valuable information about the ventilation of the upper ocean and about the formation of deep water [ Broecker and Peng , ]. Further, the regional and point‐like release of a suite of different radionuclide contaminants (such as 3 H, 90 Sr, 99 Tc, 125 Sb 129 I, 137 Cs, and transuranic actinides) by the nuclear reprocessing facilities Sellafield (formerly Windscale), Great Britain (later termed SF) and La Hague, France (later termed LH) into the Northeast Atlantic Ocean (Figure ) triggered numerous oceanographic tracer studies [ Alfimov et al ., ; Bailly du Bois et al ., ; Herrmann et al ., ; Karcher et al ., ; Nies , ]. These studies investigated the local distribution and the dispersion of anthropogenic radionuclides and were able to quantify timescales of regional ocean circulation.…”

Section: Introductionmentioning

confidence: 98%

Reconstruction of the ²³⁶U input function for the Northeast Atlantic Ocean: Implications for ¹²⁹I/²³⁶U and ²³⁶U/²³⁸U‐based tracer ages

et al. 2015

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A reconstruction of historical discharges of 236U into the Northeast Atlantic Ocean by nuclear installations is presented. The nuclear reprocessing facilities Sellafield (SF), Great Britain (GB) and La Hague (LH), France and potentially also the nuclear fuel processing installation Springfields (SP), GB represent the main contributors of 236U in the Northeast Atlantic Ocean. Because data on 236U releases is lacking, 236U discharges from SP and SF are estimated based on the U‐isotopic systematics found in the discharges from LH. The resulting reconstruction of 236U releases indicates that, until 2013, a total of (95 ± 32) kg of 236U was discharged from SF, SP, and LH. In a second step, the reconstructed 236U releases are combined with 129I data from literature and oceanic and atmospheric box models are used to derive the 129I/236U and 236U/238U input functions that, for example, can be used to calculate tracer ages of Atlantic Waters in the Arctic Ocean. Our conceptual results show that the combination of 129I/236U and 236U/238U generally allows the estimation of tracer ages over the past approximately 25 years if contributions of 236U from global fallout are considered. Finally, as a proof of concept, the new method is applied to calculate tracer ages of Arctic Ocean surface samples (collected in 2011/2012) and the results are in good agreement with literature data. We conclude that the combination of 129I/236U with 236U/238U in a dual tracer approach provides a sensitive tool for the calculation of tracer ages and ventilation rates in the North Atlantic region.

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Percentage contribution of inputs from the Atlantic, Irish Sea, English Channel and Baltic into the North Sea during 1988: A tracer-based evaluation using artificial radionuclides

Cited by 24 publications

References 12 publications

Large-scale circulation and flushing characteristics of the North Sea under various climate forcings

Large-scale circulation and flushing characteristics of the North Sea under various climate forcings

Quantitative assessment of dissolved radiotracers in the English Channel: Sources, average impact of la Hague reprocessing plant and conservative behaviour (1983, 1986, 1988, 1994)

Reconstruction of the ²³⁶U input function for the Northeast Atlantic Ocean: Implications for ¹²⁹I/²³⁶U and ²³⁶U/²³⁸U‐based tracer ages

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Percentage contribution of inputs from the Atlantic, Irish Sea, English Channel and Baltic into the North Sea during 1988: A tracer-based evaluation using artificial radionuclides

Cited by 24 publications

References 12 publications

Large-scale circulation and flushing characteristics of the North Sea under various climate forcings

Large-scale circulation and flushing characteristics of the North Sea under various climate forcings

Quantitative assessment of dissolved radiotracers in the English Channel: Sources, average impact of la Hague reprocessing plant and conservative behaviour (1983, 1986, 1988, 1994)

Reconstruction of the 236U input function for the Northeast Atlantic Ocean: Implications for 129I/236U and 236U/238U‐based tracer ages

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Reconstruction of the ²³⁶U input function for the Northeast Atlantic Ocean: Implications for ¹²⁹I/²³⁶U and ²³⁶U/²³⁸U‐based tracer ages