tidal exchange through the kuril straits abstract the tidal exchange between the okhotsk sea and the north pacific ocean is studied numerically with particular emphasis on the predominant k1 barotropic component the calculated harmonic constants of the k1 tide in and around the okhotsk sea agree well with those obtained from extensive tide gauge observations the features of the simulated tidal fields are similar to those reported in the literature since the k1 tide is subinertial in the okhotsk sea topographically trapped waves are effectively generated contributing to strong tidal currents with a maximum amplitude of over 1 5 m s 1 in the kuril straits the structures of tide induced mean flows in most passages of the straits are characterized by bidirectional currents in which the mean flow exhibits a reversal in direction across the passages this feature is clearly indicated in noaa infrared imagery the mean transport shows significant net exchange of water via several straits in the kuril islands a transport of about 5 0 sv 1 sv

a new high resolution unstructured grid finite volume arctic ocean model ao fvcom an application for tidal studies 1 a spherical coordinate version of the unstructured grid 3 d fvcom finite volume coastal ocean model has been applied to the arctic ocean to simulate tides with a horizontal resolution ranging from 1 km in the near coastal areas to 15 km in the deep ocean by accurately resolving the irregular coastlines and bathymetry in the arctic ocean coastal regions this model reproduces the diurnal k1 and o1 and semidiurnal m2 and s2 tidal wave dynamics and captures the complex tidal structure along the coast particularly in the narrow straits of the canadian archipelago the simulated tidal parameters harmonic constituents of sea surface elevation and currents agree well with the available observational data high resolution meshes over the continental shelf and slope capture the detailed spatial structure of topographic trapped shelf waves which are quite energetic along the greenland siberia and spitsbergen continental slope and shelf break areas water stratification influences the vertical distribution of tidal currents but not the water transport and thus tidal elevation the comparison with previous finite difference models suggests that horizontal resolution and geometric fitting are two prerequisites to simulate realistically the tidal energy flux in the arctic ocean particularly in the canadian archipelago

a barotropic inverse tidal model for the arctic ocean 1 we describe high resolution 5 km grid linear dynamics and inverse models of arctic ocean barotropic tides obtained with the osu tidal inversion software otis package the 8 constituent dynamics based model uses the latest ibcao bathymetry and open boundary forcing from the recent tpxo 6 2 global barotropic tidal solution this model performs significantly better than the present benchmark arctic tidal model 14 km grid by z kowalik and a proshutinsky as judged by comparisons with 300 coastal tide gauges the greatest improvements are found in the canadian arctic archipelago nares strait and the baffin bay and labrador sea and can be explained by the higher resolution of the new model in these topographically complex regions the new arctic inverse model assimilates coastal and benthic tide gauges and topex poseidon and ers altimetry for further improvements of the 4 dominant constituents m2 s2 k1 and o1

flow dynamics of a wide arctic canyon we extend and interpret acoustic doppler current profiler and conductivity temperature depth data collected in the summer of 1993 over barrow canyon in order to implement a high resolution 1 5 to 5 km model of the beaufort and chukchi seas this paper addresses physical processes relevant to the barrow canyon region using common dynamical analyses of both field data and numerical results the field data reveal the dominant physical processes that guide the design of our numerical experiments the observed velocity field shows an intense and variable down canyon flow with transports ranging from 0 5 to 1 4 sv a momentum analysis reveals that the cross canyon dynamic balance for the barotropic component is primarily geostrophic conversely the baroclinic cross canyon momentum balance is ageostrophic and secondary flow results from a local imbalance between the vertically varying coriolis acceleration and the cross canyon pressure gradient in addition to the moderate influence of stratification froude number of 0 4 and burger number of 0 06 the barotropic pressure gradient component across the canyon inferred from the large magnitude and little vertical variability of the residuals is dynamically important for both upcanyon and downcanyon flows that occur at different locations concurrently the along canyon dynamic balance is ageostrophic since the time derivative and the coriolis term are of the same order of magnitude temporal rossby number is approximately 1 an analysis of the longitudinal density and velocity fields from the model reveals that the main driving mechanism for generating the observed upcanyon flow is the nonlinear interaction of the variable barotropic flow with the steep topography stratification is maintained by the downcanyon advection of fresh and warm water from the bering and chukchi seas and the upcanyon advection of saltier and colder water from the arctic

the effects of tides on the water mass mixing and sea ice in the arctic ocean in this study we use a novel pan arctic sea ice ocean coupled model to examine the effects of tides on sea ice and the mixing of water masses two 30 year simulations were performed one with explicitly resolved tides and the other without any tidal dynamics we find that the tides are responsible for a 15 reduction in the volume of sea ice during the last decade and a redistribution of salinity with surface salinity in the case with tides being on average 1 0 1 8 practical salinity units psu higher than without tides the ice volume trend in the two simulations also differs 2 09 103 km3 decade without tides and 2 49 103 km3 decade with tides the latter being closer to the trend of 2 58 103 km3 decade in the piomas model which assimilates sst and ice concentration the three following mechanisms of tidal interaction appear to be significant a strong shear stresses generated by the baroclinic clockwise rotating component of tidal currents in the interior waters b thicker subsurface ice ocean and bottom boundary layers and c intensification of quasi steady vertical motions of isopycnals by 50 through enhanced bottom ekman pumping and stretching of relative vorticity over rough bottom topography the combination of these effects leads to entrainment of warm atlantic waters into the colder and fresher surface waters supporting the melting of the overlying ice

trapped motion around the pribilof islands in the bering sea observations in the region of the pribilof islands and canyon pic reveal a clockwise circulation around the group of islands and around each of the two largest islands st paul and st george six current meters deployed around st paul island revealed a steady clockwise flow around the island which was strongest south of the island and weakest to the east we use a high resolution tidal model in the pic region to show that this flow pattern results from tidal rectification over the shallow topography tides tidal residual currents of 10 15 cm s were predicted by the model compared to mean currents of 5 20 cm s observed at the mooring sites both diurnal and semidiurnal tidal oscillations contribute to the clockwise circulation around the islands in the diurnal band the enhanced currents occur also at the shelf slope where a tidal wave generates a shelf wave due to resonance with topography in the pic region the main shelf wave occurs in the pribilof canyon where both observations and measurements show enhancement of the diurnal tidal currents

no major deglaciation across the miocene pliocene boundary integrated stratigraphy and astronomical tuning of the loulja sections bou regreg area nw morocco 1 an integrated high resolution stratigraphy and orbital tuning is presented for the loulja sections located in the bou regreg area on the atlantic side of morocco the sections constitute the upward continuation of the upper messinian ain el beida section and contain a well exposed continuous record of the interval straddling the miocene pliocene m p boundary the older loulja a section which covers the interval from 5 59 to 5 12 ma reveals a dominantly precession controlled color cyclicity that allows for a straightforward orbital tuning of the boundary interval and for detailed cyclostratigraphic correlations to the mediterranean the high resolution and high quality benthic isotope record allows us to trace the dominantly obliquity controlled glacial history our results reveal that the m p boundary coincides with a minor partly precession related shift to lighter interglacial values in d18o this shift and hence the m p boundary may not correlate with isotope stage tg5 as previously thought but with an extra weak obliquity controlled cycle between tg7 and tg5 consequently the m p boundary and basal pliocene flooding of the mediterranean following the messinian salinity crisis are not associated with a major deglaciation and glacio eustatic sea level rise indicating that other factors such as tectonics must have played a fundamental role on the other hand the onset of the upper evaporites in the mediterranean marked by hyposaline conditions coincides with the major deglaciation step between marine isotope stage tg12 and tg11 suggesting that the associated sea level rise is at least partly responsible for the apparent onset of intermittently restricted marine conditions following the main desiccation phase finally the loulja a section would represent an excellent auxiliary boundary stratotype for the m p boundary as formally defined at the base of the trubi marls in the eraclea minoa section on sicily

modeling of topographically amplified diurnal tides in the nordic seas abstract diurnal tidal constituents k1 and o1 are calculated in the nordic seas with a numerical space grid of about 10 km this allows resolution of the structure of enhanced tidal currents generated by near resonant topographic vorticity waves at the yermak plateau the resonance properties of the yermak plateau are investigated in the period range 20 30 h the main resonance peak is close to the 26 h period and the resonance curve envelops a wide range of periods this broad resonance peak explains the enhancement of both diurnal tidal components separated by a 2 h difference and the stability of the resonance phenomena the model results describe well the observed flow pattern over the yermak plateau including the current ellipse rotation

water mass distribution and polar front structure in the western barents sea the water mass distribution in the western barents sea the thermohaline structure of the western barents sea polar front and the local formation of a dense water mass are described on the basis of an analysis of historical hydrographic data this study concentrated on the frontal region between bjornoya and hopen island where arctic water is found on the spitsbergen bank and atlantic water in the bear island trough and hopen trench the distributions of atlantic and arctic waters in relation to topography were consistent with the hypothesis that the location of the polar front is fixed at about the 250 m isobath by the barotropic circulation of atlantic water within the bear island trough and hopen trench in winter vertical gradients of temperature and salinity were weak throughout the frontal region consistent with a barotropic topographically controlled front in summer vertical gradients remained weak below 100 m depth but increased in the upper layer as a result of the presence of fresh warm surface water produced by melting ice the topographic control of thermohaline properties at the surface was disrupted by the meltwater pool and the meltwater contributed to water mass modification in the frontal region the following seasonal cycle of water mass formation was hypothesized summer heating melts the sea ice on the spitsbergen bank and produces the surface meltwater pool this meltwater not only increases vertical thermohaline gradients on the bank but also crosses the front and freshens the surface layer throughout the western barents sea subsequent winter cooling which creates ice over the bank also forms dense water in the bear island trough and hopen trench by convective mixing of atlantic water and the overlying meltwater

absolute transport estimates of total and individual water masses in the northern greenland sea derived from hydrographic and acoustic doppler current profiler measurements 1 conductivity temperature depth transects across the greenland sea and fram strait provide geostrophic shear velocity profiles which were absolutely referenced using the simultaneous measurements from a vessel mounted acoustic doppler current profiler the measurements are performed mainly in 1997 with supplements in 1998 1995 and 1994 the observations confirm that all currents within the area have a strong barotropic component so that calculations based on the geostrophic method underestimate the transports considerably particulars for the transports of mass and heat are given for all individual and total water masses in the area meanders and eddies on horizontal scales between 20 and 70 km affect the total transport in the west spitsbergen current significantly the atlantic water transports range between 2 and 7 sv mainly dominated by the cross sectional area occupied by this water mass the total northward heat transport across 75 n is estimated as 54 7 tw and across 79 40 n as 42 tw in september 1997

barents sea tidal and inertial motions from argos ice buoys during the coordinated eastern arctic experiment a harmonic analysis constrained to estimate separately ice motions forced by tides and inertial oscillations was applied to observed positions of argos buoys deployed on drifting multiyear sea ice in the eastern arctic ocean and barents sea during the coordinated eastern arctic experiment 1988 1989 individual tidal components were estimated at 15 day intervals and inertial oscillations were estimated at 3 day intervals the s2 tidal component was distinguishable from inertial motions south of 79 n and the m2 tidal component was distinguishable from the inertial motion north of 77 5 n computed ice velocities of up to 70 cm s 1 for m2 tidal motion over spitsbergen bank southeast of svalbard agreed reasonably well with the regional tidal models no ice cover of gjevik and of kowalik regional differences in the energy distribution in the arctic basin low barents shelf high and spitsbergen bank extreme were emphasized by this technique the m4 tidal component in the ice motion was typically as large over the barents shelf as the inertial oscillation

changes in the flow of atlantic water into the arctic ocean since the last deglaciation evidence from the northern svalbard continental margin 80 n 1 the svalbard archipelago is located in the high arctic 76 80 n within the northernmost reach of the west spitsbergen current which is the continuation of the north atlantic current in this specific setting close to the polar front even small variations in the current system are expected to give large and distinct signals in paleoceanographic parameters thus the svalbard area is ideal for monitoring the past history of the inflow of atlantic water to the arctic ocean we have studied sediment core np94 51 taken outside the mouth of the hinlopen strait on the northern svalbard shelf the paleoceanographic development of the last deglaciation and the holocene has been reconstructed using benthic and planktonic foraminifera oxygen isotopes and ice rafted detritus the results show that the first strong subsurface inflow of atlantic water to the arctic ocean after the last glacial maximum commenced at 12 6 14c kyr b p circa 15 000 calendar cal years b p during the bolling allerod interstadial during the younger dryas polar conditions prevailed at the surface with extensive sea ice cover and the inflow of atlantic derived water was generally diminished the inflow of more saline but still cold atlantic water was relatively strong during the early holocene and caused intensified seasonal biological productivity the atlantic water inflow declined gradually during the mid holocene between 4500 and 1100 cal years b p the inflow was very weak and the bottom waters over the northern svalbard margin were cold and of lower salinity during the last 1000 years climatic conditions improved such that the subsurface inflow of atlantic derived water increased however the surface waters were still cold

the barents sea polar front in summer in august 1992 a combined physical oceanography and acoustic tomography experiment was conducted to describe the barents sea polar front bspf and investigate its impact on the regional oceanography the study area was an 80 70 km grid east of bear island where the front exhibits topographic trapping along the northern slope of the bear island trough conductivity temperature depth current meter and acoustic doppler current profiler adcp data combined with tomographic cross sections presented a highly resolved picture of the front in august all hydrographic measurements were dominated by tidal signals with the strongest signatures associated with the m2 and s2 semidiurnal species mean currents in the warm saline water to the south of the front derived from a current meter mooring and adcp data were directed to the southwest and may be associated with a barotropic recirculation of norwegian atlantic water naw within the bear island trough the geostrophic component of the velocity was well correlated with the measured southwestward mean surface layer flow north of the front the frontal structure was retrograde as the frontal isopleths sloped opposite to the bathymetry the surface signature of the front was dominated by salinity gradients associated with the confluence of atlantic and arctic water masses both warmed by insolation to a depth of about 20 m the surface manifestation of the front varied laterally on the order of 10 km associated with tidal oscillations below the mixed layer temperature and salinity variations were compensating defining a nearly barotropic front the horizontal scale of the front in this region was 3 km or less at middepth beneath the frontal interface tomographic cross sections indicated a high frequency 16 cpd upslope motion of filaments of naw origin the summertime bspf was confirmed to have many of the general characteristics of a shelf slope frontal system mooers et al 1978 as well as a topographic circulatory front federov 1983

tidally induced diapycnal mixing in the kuril straits and its role in water transformation and transport a three dimensional nonhydrostatic model experiment 1 baroclinic processes generated by the k1 tidal flow around the kuril straits and their role in the linkage between the okhotsk sea and the north pacific are investigated using a three dimensional nonhydrostatic model large amplitude unsteady lee waves are generated around sill tops all along the kuril island chain and induce significant density inversions from the sea surface down to the 27 6 density layer along with this wave breaking a large flow of energy takes place from the swift tidal flow regions to greater depths as a result of the clockwise propagation of both the topographically trapped waves around the islands and the remaining unsteady lee waves such wave generation and energy exchange eventually cause intense diapycnal mixing over the shallow topographic features and near the bottom leading to a maximum diapycnal diffusivity of over 103 cm2 s 1 even in the deep bussol strait which is thought to be the main exit of the okhotsk sea water considerable mixing corresponding to diapycnal diffusivity values of between 10 50 cm2 s 1 occurs vigorous mixing in the shallow regions produces low potential vorticity pv water in the upper layer and high pv water below accordingly pv fronts are formed along the island chain and sustain instabilities that in turn release baroclinic eddies with low core pv values these features are indicated in recent satellite imagery and in situ observations suggesting that the tide is the controlling factor in the formation of fronts observed in the kuril straits tidally induced mean transport across the straits is estimated to reach 26 sv 1 sv 106 m3 s 1 which is much larger than in the barotropic case however most of the exchanged water tends to circulate around the islands due to the effect of bottom topography whereas eddies pinched off from the tidal fronts carry the exchanged water offshore the amount of eddy driven offshore transport away from the islands reaches 14 sv with roughly half being directed to the north pacific this significant offshore transport spreads the effect of the diapycnal mixing taking place in the straits over wider areas of the north pacific and the okhotsk sea for example the pv values generated in the eddies differ by 30 40 from the ambient water on average whereas sea surface salinity within the eddies is 0 1 psu higher than the surroundings corresponding to the density increase of 0 08 thus the eddy transport provides significant pv and salinity fluxes to both the north pacific and the okhotsk sea hence we infer that a combination of tidally driven processes taking place at the passages leads to the formation of eddies that play a central role in water transport and transformation and are an essential aspect of the physical interplay between the okhotsk sea and the north pacific

observations of turbulent mixing and hydrography in the marginal ice zone of the barents sea 1 measurements of hydrography currents microstructure shear and temperature were made at ice drift stations in the marginal ice zone miz of the northern barents sea highly variable mixing regimes were observed within and below the pycnocline elevated turbulent dissipation 5 15 10 7 w kg 1 was associated with strong vertical shear between the surface layer and the subsurface currents as well as strong tidal flow over shallow topography dissipation in the pycnocline was enhanced at stations with strong wind forcing during drifts under relatively calm wind and away from strong fronts and abrupt topography station mean dissipation values were up to a factor 50 lower and double diffusion contributed significantly to the vertical heat flux where hydrography favored diffusive layering independent measures of turbulent length scale from density overturns compared well with those inferred from the dissipation measurements the variability of dissipation was better captured using a scaling by shear suggested for shelves rather than shear variance models appropriate to the deep open ocean sufficiently resolved patches of enhanced temperature microstructure used in combination with dissipation measurements suggest mixing efficiency of rf 0 2 for patches stable to double diffusion comparable to the conventional upper bound of rf 0 17 mixing efficiency for double diffusive convection favorable cases is found to be significantly larger rf 0 36 water mass modification and fluxes of nutrients and dissolved carbon were found to have large local variability in accordance with the observed variability of vertical mixing in the miz

age refinement of the messinian salinity crisis onset in the mediterranean we propose a revised age calibration of the messinian salinity crisis onset in the mediterranean at 5 971 ma based on the recognition of an extra gypsum cycle in the transitional interval of the perales section sorbas basin spain and the revision of the magnetostratigraphy of the monticino section vena del gesso basin italy this age re calibration allows to state more accurately that i the interval encompassing the msc onset is continuous thus ruling out any erosional feature or stratigraphic hiatus related to a major sea level fall affecting the mediterranean ii the first gypsum was deposited during the summer insolation peak at 5 969 ma associated with an eccentricity minimum and roughly coincident with glacial stage tg32 iii the msc onset was preconditioned by the tectonically driven reduction of the hydrological exchanges with the atlantic ocean and finally triggered by glacial conditions in the northern hemisphere and by arid conditions in northern africa

model simulations of the tides in the barents sea a large scale numerical model covering the nordic seas and the arctic ocean with 25 12 5 km grid resolution has been applied to study the tides in the barents sea tidal charts for elevation and phase are presented for the four tidal constituents m2 s2 n2 and k1 computed harmonic constants for elevation and current have been compared with observations from 46 coastal and pelagic tidal stations the agreement between model and field data is good for most stations with an overall standard deviation of 2 5 cm for amplitude 18 30 for phase and 1 3 cm s for current speed calculated tidal residual currents show anticyclonic eddy circulation over the svalbard bank and around bear island and hopen particle trajectories and streaklines due to the tidal flow over svalbardbanken have been calculated and the computed streaklines are found to agree well with observed rifts in the ice cover due to stranded icebergs

crustal uplift due to ice mass variability on upernavik isstrom west greenland abstract we estimate the mass loss rate of upernavik isstrom ui using surface elevation changes between a spot 5 digital elevation model dem from 2008 and nasa s airborne topographic mapper atm data from 2010 to assess the validity of our mass loss estimate we analyze gps data between 2007 and 2011 from two continuous receivers upvk and srmp which are established on bedrock and located 65 and 2 km from the front of ui respectively we construct along track elevation changes on ui for several time intervals during 2005 2011 based on atm spot 5 and ice cloud and land elevation satellite icesat data to assess temporal changes of ui we estimate a mass loss rate of 6 7 4 2 gt yr over an area of 1600 km 2 the ice mass loss occurs primarily over the northern glacier of ui this pattern is also observed 40 km upstream where we observe glacier thinning at a rate of 1 6 0 3 m yr across the northern portion of ui and 0 5 0 1 m yr across the southern portion gps measurements suggest bedrock uplift rates of 7 6 0 6 mm yr upvk and 16 2 0 6 mm yr srmp the modeled ice mass loss of ui causes bedrock uplift rates of 1 3 0 6 mm yr upvk and 8 3 4 2 mm yr srmp including additional contributions from ice mass changes outside ui and from glacial isostatic adjustment gia we obtain total modeled uplift rates of 4 7 0 6 mm yr upvk and 13 8 4 2 mm yr srmp the modeled uplift rates from our ui ice mass loss are substantially lower indicating that additional mass loss is taking place outside of ui we obtain a difference of 0 6 mm yr between the modeled and observed relative uplift rates srmp relative to upvk suggesting that the mass loss of ui is well captured in the model we observe elevation changes from 15 to 40 m yr near the front during the period 2005 2011 indicating that ui undergoes large variations in thinning pattern over short time spans

a numerical model study of parameters influencing tidal currents in the irish sea the mathematical formulation of a mixed finite difference modal three dimensional tidal model of the irish sea using quadratic bottom friction is briefly presented by using an expansion of modes in the vertical a continuous current profile from sea surface to seabed can be computed and accurate comparisons made with tidal currents measured at a range of positions throughout the water column the sensitivity of current profiles to various eddy viscosity formulations and coefficients of bottom friction are examined in detail also the influence of open boundary conditions and water depths upon computed tidal elevations and currents is examined in common with other earlier published calculations initial results show that with previous formulations of eddy viscosity and friction an accurate distribution of sea surface elevations is accompanied with computed currents which exceed observations by the order of 20 cm s 1 however results from the sensitivity study presented here show that elevations and currents above the bottom boundary in good agreement with observations can be obtained with alternative formulations of viscosity and other friction coefficients together with current input to the radiation condition however computed near bed currents are still larger than those observed although a slight increase in water depth and bottom friction coefficients corrects this calculations clearly show that the computation of near bed currents subject to the constraints of obtaining accurate elevation and current distributions is the most sensitive test of the model excellent agreement between computed and observed currents and elevations was obtained in a final series of calculations using appropriate parameterizations of eddy viscosity and bottom friction

diurnal tides in the arctic ocean a two dimensional numerical model with a space grid of about 14 km is applied to calculate diurnal tidal constituents k1 and o1 in the arctic ocean calculated corange and cotidal charts show that along the continental slope local regions of increased sea level amplitude highly variable phase and enhanced currents occur it is shown that in these local regions shelf waves topographic waves of tidal origin are generated in the arctic ocean and northern atlantic ocean more than 30 regions of enhanced currents are identified to prove the near resonant interaction of the diurnal tides with the local bottom topography the natural periods of oscillations for all regions have been calculated the flux of energy averaged over the tidal period depicts the gyres of semitrapped energy suggesting that the shelf waves are partially trapped over the irregularities of the bottom topography it is shown that the occurrence of near resonance phenomenon changes the energy flow in the tidal waves first the flux of energy from the astronomical sources is amplified in the shelf wave regions and afterwards the tidal energy is strongly dissipated in the same regions

topographic enhancement of tidal motion in the western barents sea a high resolution numerical lattice is used to study a topographically trapped motion around islands and shallow banks of the western barents sea caused both by the semidiurnal and diurnal tidal waves observations and model computations in the vicinity of bear island show well developed trapped motion with distinctive tidal oscillatory motion numerical investigations demonstrate that one source of the trapped motion is tidal current rectification over shallow topography tidal motion supports residual currents of the order of 8 cm s 1 around bear island and shallow spitsbergenbanken the structures of enhanced tidal currents for the semidiurnal components are generated in the shallow areas due to topographic amplification in the diurnal band of oscillations the maximum current is associated with the shelf wave occurrence residual currents due to diurnal tides occur at both the shallow areas and the shelf slope in regions of maximum topographic gradients surface manifestation of the diurnal current enhancement is the local maximum of tidal amplitude at the shelf break of the order of 5 to 10 cm tidal current enhancement and tidally generated residual currents in the bear island and spitsbergenbanken regions cause an increased generation of ice leads ridges and trapped motion of the ice floes

ice production and brine formation in storfjorden svalbard brines which appear as salty and cold bottom water layers on arctic shelves form by salt rejection during sea ice formation high ice production occurs in latent heat polynyas such as the one that appears in storfjorden under northerly winds using ers 2 synthetic aperture radar imagery we observed the ice cover in storfjorden over the winter 1997 1998 revealing an area of over 6000 km 2 of the open water and thin ice that are characteristic of a polynya changes in the polynya extent correlated well with a simple wind driven polynya size algorithm furthermore using a frazil ice formation algorithm and the hypothesis of ice accumulation at the lee side of the polynya we distinguished between open water thin ice and fast pack ice the average polynya width during the 6 winter months was about 30 km with a maximum of 130 km in march thus storfjorden was composed of 5 6 fast and pack ice and 1 6 polynya open water occupied about half of the polynya the other half was composed of brash ice and thin ice involved in ridging and rafting a total ice volume of 40 km 3 was produced in storfjorden between november 15 1997 and may 15 1998 about 57 of it was formed in the open water area 9 in the thin ice area and 34 in the fast pack ice area this ice production released more than 1 gt gigaton of salt able to increase the salinity of the storfjorden waters by 1 4 practical salinity units psu assuming that brine enriched waters are 0 3 psu more saline than the parent waters the above salt release is able to ventilate storfjorden 4 5 times during the course of the productive season