paleo sea ice conditions of the amundsen gulf canadian arctic archipelago implications from the foraminiferal record of the last 200 years 1 four boxcores were collected as part of the canadian arctic exchange shelf study cases in the amundsen gulf at water depths of 59 m to 600 m data from these cores help to develop a record of changes in the oceanographic history of the area over the last 200 years with particular reference to the indication of paleo sea ice formation a key element of the arctic ecosystem the four sites cover a range of water depths and environments to provide a basis for comparison the benthic foraminifera of sites ca 06 253 m water depth and ca 18 600 m water depth show an increase in arctic surface water associated agglutinated foraminifera over the last 100 years uppermost 8 to 16 cm these are indicating a decrease in sea ice cover and in cold saline arctic bottom water influence these are similar to canadian arctic archipelago postglacial faunas this contrasts with abundant planktic foraminifera at the same stations suggesting strong oceanic arctic surface influence little freshwater in the central gulf the foraminifera of sites 403b 59 m water depth and 415b 56 m water depth at the outermost edges of amundsen gulf indicate that the present day location of the winter flaw lead has been in place for at least the last 100 years with foraminiferal faunas similar to those of the beaufort shelf additionally station 415 is on an earlier holocene shoreline that is covered with cobbles

the cold climate origin of inertinite rich gondwana coals abstract in the inertinite rich permian coals of australian there occurs a close association between inertodetrinite and alginite of a kind which has been generally overlooked in the past the association is believed to be a consequence of the environment of deposition and especially the climate which is inferred to have been one of wet cool summers and freezing winters the inertodetrinite formed by drying out of a gelified homogenised precursor the algae lived at the periodically desiccated surface of the accumulating peat much of the evidence for these conclusions has come from the combined use of light microscopy and transmission electron microscopy

upwelling of atlantic water along the canadian beaufort sea continental slope favorable atmospheric conditions and seasonal and interannual variations abstractthe role of wind forcing on the vertical displacement of the 1 c isotherm and 33 8 isohaline depths was examined based on snapshots of historical 1950 2013 temperature and salinity profiles along the mackenzie continental slope beaufort sea it is found that upwelling is correlated with along slope northeast t59 winds during both ice free and ice covered conditions although the wind impact is more efficient during the ice free season one of the most important factors responsible for vertical displacements of isopycnals is sustained wind forcing that can last for several weeks and even longer it accounts for 14 55 of total variance in isotherm isohaline depths although these numbers might be underestimated the upwelling and downwelling events are discussed in the context of the interplay between two regional centers of action the beaufort high and aleutian low that control the wind pattern over the southern beaufort sea the probability of upwelling favorable wind occurrence is close

estimating sea ice area flux across the canadian arctic archipelago using enhanced amsr e 1 enhanced resolution advanced microwave scanning radiometer amsr e imagery is used to estimate daily sea ice area fluxes between the canadian arctic archipelago and the arctic ocean and baffin bay for the period september 2002 to june 2007 over the period amundsen gulf and m clure strait exported 54 103 km2 of sea ice area or roughly 77 km3 of sea ice volume each year into the arctic ocean export import into the arctic ocean through the queen elizabeth islands is small and uncertain since no estimates for july and august could be made due to atmospheric attenuation of the microwave signal lancaster sound exported 68 103 km2 of sea ice area or roughly 102 km3 of ice volume into baffin bay this produced a net loss of sea ice area of about 122 103 km2 or roughly 174 km3 a 1 which is presumed to be generated from within the archipelago itself mainly through the stationary and transient polynyas and leads that form each winter daily ice area fluxes for amundsen gulf ag and lancaster sound ls were as high as 2500 km2 d 1 and were event driven depending on synoptic scale atmospheric circulation and the mobility of the sea ice mean sea level pressure difference across each gate is moderately correlated with daily sea ice area fluxes despite the fact that free ice drift conditions are not always met in the region cross gradient and daily sea ice area flux for lancaster sound show a large number of counter gradient ice flux occurrences suggesting that local mesoscale winds nongeostrophic and perhaps ocean currents play a role in transporting sea ice through this gate monthly ice fluxes for the ag and ms gate were positively correlated with the ao index indicating that a strong beaufort sea high pressure and gyre correspond to more export into the beaufort sea monthly fluxes for the ls gate were positively correlated with the nao index indicating that strong southerly atmospheric circulation over baffin bay increases ice export into baffin bay from lancaster sound

investigations of newly formed sea ice in the cape bathurst polynya 1 structural physical and optical properties 1 the physical structural and optical properties of newly formed ice types were studied in the cape bathurst polynya 71 n 127 w during fall freezeup in october to early november 2003 variable meteorological conditions with occasional snowfall resulted in the formation of numerous ice types and surface conditions ice samples were collected from horizontally homogeneous surfaces representative of the area crystallographic analysis on 33 ice cores revealed highly variable growth conditions and formation mechanisms in the area the mean fraction of granular ice was 33 while intermediate granular columnar and columnar ice contributed 37 and 30 respectively salinity profiles in the ice were c shaped and as the ice grew thicker bulk salinities decreased according to 4 582 13 358 hi cm these conditions resulted in brine volumes ranging from 4 to 46 bare ice surfaces commonly formed a high salinity brine skim layer due to brine expulsion salinities up to 40 were observed in this layer under suitable conditions frost flowers formed on the ice and their presence was related to characteristic ice microstructure with crystals that appeared disc like in shape fine grained snow ice was formed when snow merged with surface brine to create a complex hypersaline surface at the snow ice interface the spectral reflectance for the thin ice types was most strongly related to surface conditions the presence of frost flowers significantly increased the reflectance independent of snow precipitation any increase in ice thickness was found to have little effect on the reflectance once a 20 30 mm thick snow layer was present

an annual study of inorganic and organic nitrogen and phosphorus and silicic acid in the southeastern beaufort sea 1 water column samples from the mackenzie shelf the beaufort sea and the amundsen gulf were obtained during 2003 2004 to investigate nutrient dynamics in an arctic ecosystem influenced by a large river and flaw lead polynya nutrient inventories in the upper water column showed a significant seasonal drawdown of nitrate no3 and silicic acid si oh 4 1 1 75 mol mol and subsequent accumulation of nitrite no2 and ammonium nh4 dissolved organic nitrogen and phosphorus concentrations don and dop were elevated in surface waters during the time of peak phytoplankton growth bloom and postbloom phases and covaried in a 17 1 molar ratio vertical profiles showed the typical middepth maxima in no3 po43 and si oh 4 at salinity 32 33 1 the concentration of dop 0 76 0 27 mol p l 1 was also 2 times higher in this layer compared to the surface average and inversely correlated with the water mass tracer n n no3 16 po43 2 9 0 87 suggesting that pacific derived waters were a source of the enrichment below the mixed layer don was generally constant with depth although averaged profiles like those of urea suggested the presence of subsurface maxima at 50 m and between 250 and 300 m regeneration ratios varied with depth and were approximately 9 0 mol o2 mol no3 and 122 5 mol o2 mol po43 in shallow pacific derived waters halocline layer and 17 4 and 193 5 in deep atlantic waters atlantic layer respectively deep waters of the amundsen gulf contained an excess of 1 7 mol no3 l 1 0 12 mol po43 l 1 and 6 2 mol si oh 4 l 1 and a deficit in o2 relative to waters of similar density in the beaufort sea in proportions consistent with the remineralization ratios derived from oxygen nutrient regressions enhanced export of particulate matter from the overlying polynya and subsequent remineralization at depth are hypothesized to create this nutrient enrichment

the genesis of coal from the viewpoint of coal petrology abstract the genesis of the microscopic constituents of coal macerals and of maceral associations microlithotypes representing various coal facies is discussed in the light of recent advances that have been made in the study of coals and modern peats peat microscopy especially promoted the understanding of humification and biological gelification both of which are decisive for the genesis of huminites vitrinites in brown coals and hard coals respectively microbial activity during peatification has been documented by chemists microbiologists and petrologists and recently by electron microscopical observations in coals this activity leads to the incorporation of lipid substances into the humic matter and later influences the chemical physical and technological properties of vitrinites geochemical gelification transforms the huminites of brown coals into the vitrinites of bituminous coals and is probably caused by the onset of bitumen generation in coal in this process the hydrogel brown coal is transformed to the bitumogel bituminous coal coal as a source rock for oil has become an important research subject for coal petrologists and oil exploration the formation of more or less liquid bitumen and its later cracking to gaseous hydrocarbons leads to the coalification jumps of the macerals especially liptinites and vitrinites and to the generation of secondary macerals like exsudatinite bitumen and micrinite dead carbon bituminization in coal has been revealed by the use of fluorescence microscopy which also found the presence of new liptinite macerals bituminite fluorinite and exsudatinite and suggests a higher proportion of algal material in coals than was thought earlier the genesis of various types of inertinite macerals will probably become an increasingly important subject of research especially with regard to rank inertinites that seem to attain their high inertinitic reflectance initially during coalification besides the origin of macerals the origin of various coal facies in terms of maceral associations is considered in relation to the palaeogeographic depositional milieu the peat forming vegetation palaeoclimate water and nutrient supply acidity marine and calcareous influence and fire with examples from euramerican carboniferous coals gondwana coals and tertiary brown coals vegetation water and oxygen supply eh conditions are most important for the generation of coal facies vegetation has been reconstructed with the help of palaeobotany including palynology cuticular analysis and wood anatomy in brown coals and with the study of petrified permineralized peats preserved in coal balls the microscopical investigations of botanically recognizable plant remains isolated from coals or accompanying rocks has been especially informative however the results of palynological and cuticular analyses should be evaluated with caution considering the varying resistance of palynomorphs and cuticles and in the case of palynomorphs their possible extrapaludal origin microscopical studies of modern peats that were derived from different types of vegetation growing in different hydrological environments have been very helpful in interpreting coal facies especially in brown coals the much disputed origin of brown coal lithotypes is considered in detail for hard coals there seems to be agreement that coal layers rich in vitrites and liptinite poor clarite were deposited in wet forest swamps that microlayered liptinite rich clarites are sub aquatic humic muds and that inertinite rich durites represent oxidized peats the origin of liptinite rich durites is controversial either subaquatic muds or oxidized peats the latter perhaps from raised bogs a recent trend in the literature is the assumption that many if not all mineable coal seams have been deposited in raised bogs under ombrogenous oligotrophic conditions although raised bogs with a dense arborescent vegetation are known from borneo it seems not probable that most seams which were deposited in foredeeps or steadily sinking graben zones are of ombrogenous origin although a succession from relatively wet and eutrophic to relatively dry and oligotrophic conditions may be true for occasional seams but as in modern peats striking changes of coal facies are commonly caused by hydrological events e g inundations as a consequences of crevasses or of fires that burned the peat the origin of the inertinite rich gondwana coals is discussed in relation to their specific climatic conditions and a comparison with sub arctic peats is recommended coals influenced by marine and calcareous conditions are characterized by high contents of sulfur and pyrite as well as by hydrogen rich vitrinites with a relatively low reflectance and high fluorescence all due to a strong bacterial activity in peats of low acidity proposals for further research are made in the conclusions

spatial and temporal variability of sea ice in the southern beaufort sea and amundsen gulf 1980 2004 1 changing extent location and motion of the arctic perennial pack affect the annual evolution of seasonal ice zones canadian ice service digital ice charts covering the southern beaufort sea and amundsen gulf are used to illustrate summer and winter conditions and trends between 1980 and 2004 for several sea ice stages of development results illustrate average sea ice conditions within the region in summer and winter for predominant sea ice types and changes in the relative concentration of sea ice types in summer and winter in summer a trend toward increased old sea ice concentration occurred near the mouth of amundsen gulf with a trend toward decreasing summer first year sea ice farther west in winter increasing thick first year sea ice extent appears to be replacing young sea ice within the flaw lead system in the region the dynamically driven breakup of sea ice in spring in the amundsen gulf is a highly variable event taking anywhere between 2 and 22 weeks to completely remove ice from the gulf the timing and duration of the open water season depends upon the extent and timing of old ice influx freezeup occurs very quickly proceeding from west to east with little temporal variability the results of this paper are used to set the context for the canadian arctic shelf exchange study cases in terms of sea ice dynamic and thermodynamic processes

hydrographic conditions during the 2002 sbi process experiments abstract a review of the hydrographic data from the 2002 western arctic shelf basin interactions sbi process cruises permits the following conclusions 1 temperature salinity relationships were similar to canonical descriptions but at five stations in the outer shelf slope region warm high salinity atlantic layer water appeared to have risen displaced the lower halocline and mixed with shelf upper halocline water 2 primary production in the sbi study region was strongly influenced by the advection of dissolved inorganic nitrogen din entering via bering strait this import of din ammonium nitrate nitrite is modified by local processes but without the bering strait inflow biological productivity in the sbi region would be much lower 3 in comparison to the inflowing atlantic waters din urea phosphate and din urea silicate ratios in the pacific waters that dominated the upper 150 m of the water column were low they were also low relative to redfield uptake ratios for phytoplankton 4 microbial processes continue to destroy din in significant quantities as the pacific waters transit the sbi region 5 nitrate and ammonium were the principal contributors to din nitrite concentrations were always

two circulation regimes of the wind driven arctic ocean the major goal of this paper is to demonstrate the existence in the arctic ocean of two regimes of wind forced circulation we simulated the vertically averaged currents sea level heights and ice drift in the arctic ocean from 1946 to 1993 using a two dimensional wind forced barotropic model that includes frictional coupling between the ocean and ice the model has a spatial resolution of 55 5 km and is driven by winds river runoff and an imposed but realistic sea level slope between the pacific and the atlantic oceans there is a good agreement between velocities from observed buoy motions and velocities of modeled ice drift even though the model lacks ocean baroclinicity and ice thermodynamics the results indicate that wind driven motion in the central arctic alternates between anticyclonic and cyclonic circulation with each regime persisting for 5 7 years based upon our analysis of the modeled sea level and ice motion anticyclonic wind driven motion in the central arctic appeared during 1946 1952 1958 1963 1972 1979 and 1984 1988 and cyclonic motion appeared during 1953 1957 1964 1971 1980 1983 and 1989 1993 shifts from one regime to another are forced by changes in the location and intensity of the icelandic low and the siberian high the two regimes may help explain the significant basin scale changes in the arctic s temperature and salinity structure observed recently the great salinity anomaly and the variability of ice conditions in the arctic ocean

preface to special section on beaufort gyre climate system exploration studies documenting key parameters to understand environmental variability the beaufort gyre bg of the arctic ocean is one ofthe most hostile and inaccessible areas of the globe untillate 1920s most of it had never been measured or evenexplored the region s harsh climate winter darkness andthick drifting sea ice deterred potential observers and madethis area inaccessible to scientific expeditions the bg isa unique phenomenon comprising a set of specific atmo spheric sea ice and oceanic conditions that have significantinfluence on the arctic climate the papers of this specialissue focus on the atmospheric sea ice oceanographic andsome biogeochemical features of this region and describethe bg system variability at seasonal to decadal timescales employing historical and the most recent data simplehypotheses and models to estimate changes

on the spatiotemporal behavior of sea ice concentration anomalies in the northern hemisphere 1 reduction in the aerial extent and thickness of sea ice in the northern hemisphere is an important element in understanding how the arctic responds to global scale climate variability and change previous studies have demonstrated a significant reduction in minimum sea ice extent serreze et al 2003 with record reduction in 2005 observational studies attribute this phenomenon to variations in sea level pressure and large scale atmospheric teleconnection patterns such as the northern annular mode nam deser et al 2000 serreze et al 2003 in this study we examine variations in sea ice in the context of spatiotemporal variability of sea ice concentration sic anomalies in the northern hemisphere during the onset of ice formation examined in particular are timescales associated with coherent regions of persistence in an e folding time spatial distribution efsd annual variations of weekly sic anomalies are studied and spatial relations between positive and negative sic anomalies are explored on a hemispheric scale the results from this investigation demonstrate coherent sic persistence patterns throughout the northern hemisphere with timescales ranging from 3 to 7 weeks spatial correspondence between negative trends in sic anomalies and the efsd suggests that the same mechanism may be responsible for both increased ice reduction and persistence in this region examination of spatial coherence in sic anomalies indicates that maximum sic anomalies prevail near the kara sea beaufort sea and chukchi sea regions during late summer early fall from 1979 to 2004 a latitudinal assessment at 80 70 and 60 n indicates a poleward shift and retreat in sic anomalies while also underlining the decadal shift in variability often attributed to the nam

atmospheric controls on sea ice motion in the southern beaufort sea 1 the beaufort sea ice gyre is characterized in winter months by an anticyclonic regime associated with sea level pressure slp highs previous studies have shown instances of a reversal in this regime in summer months with the arrival of slp lows over the beaufort sea while also demonstrating a link to variations in lower stratospheric potential vorticity in this study we examine the role of relative vorticity in describing dynamic variability on weekly timescales from the surface to the middle stratosphere results from this analysis show that the beaufort gyre is characterized predominantly by anticyclonic activity throughout the year for the time interval considered from 1979 to 2000 with a summer reversal to cyclonic activity whose strength and duration varies between years these reversals coincide with reversals in slp based on a correlation analysis comparison of ice and atmospheric relative vorticity fields in the beaufort sea region bsr for all weeks from 1979 to 2000 indicates that sea ice and lower tropospheric processes are anticorrelated at zero time lag this is in contrast to relative vorticity fields at 10 mbar which exhibit maximum correlation between stratospheric and sea ice responses when 10 mbar leads ice relative vorticity by 2 6 weeks

seasonal ice loss in the beaufort sea toward synchrony and prediction the seasonal evolution of sea ice loss in the beaufort sea during 1979 2012 is examined focusing on differences between eastern and western sectors two stages in ice loss are identified the day of opening doo is defined as the spring decrease in ice concentration from its winter maximum below a value of 0 8 areal concentration the day of retreat dor is the summer decrease below 0 15 concentration we consider three aspects of the subject i e i the long term mean ii long term linear trends and iii interannual variability we find that in the mean doo occurs earliest in the eastern beaufort sea ebs owing to easterly winds which act to thin the ice there relative to the western beaufort sea wbs where ice has been generally thicker there is no significant long term trend in ebs doo although wbs doo is in fact trending toward earlier dates this means that spatial differences in doo across the beaufort sea have been shrinking over the past 33 years i e these dates are becoming more synchronous a situation which may impact human and marine mammal activity in the area retreat dates are also becoming more synchronous although with no statistical significance over the studied time period finally we find that in any given year an increase in monthly mean easterly winds of 1 m s during spring is associated with earlier summer dor of 6 15 days offering predictive capability with 2 4 months lead time

seismic noise emission induced by seismic waves the in situ rock undergoing different kinds of deformation accumulates elastic energy that can be released spontaneously or under artificial effect triggering of energy can also be performed by means of a dynamic excitation caused by elastic waves we carried out special field investigations with the use of seismic vibrators vibroseis like sources to study the effect of the energy release under the influence of seismic waves in the first experiment we conducted borehole observations of high frequency seismic noise in two narrow frequency bands around 500 hz and 1 khz the induced noise emission occurred in both frequency windows when the medium had been irradiated with the low frequency seismic vibrations intensity of emission was proportional to the mechanical power of a vibrator in the second experiment we carried out downhole measurements of a broad band seismic noise they showed a gradual increase of the noise energy in the frequency range 100 200 hz during a series of monochromatic vibrations with frequency of 67 hz facts observed give evidence that the elastic energy which accumulated during the rock deformation can be triggered by a relatively weak seismic excitation

organic petrology and coalbed gas content wilcox group paleocene eocene northern louisiana abstract wilcox group paleocene eocene coal and carbonaceous shale samples collected from four coalbed methane test wells in northern louisiana were characterized through an integrated analytical program organic petrographic analyses gas desorption and adsorption isotherm measurements and proximate ultimate analyses were conducted to provide insight into conditions of peat deposition and the relationships between coal composition rank and coalbed gas storage characteristics the results of petrographic analyses indicate that woody precursor materials were more abundant in stratigraphically higher coal zones in one of the cbm wells consistent with progradation of a deltaic depositional system holly springs delta complex into the gulf of mexico during the paleocene eocene comparison of petrographic analyses with gas desorption measurements suggests that there is not a direct relationship between coal type sensu maceral composition and coalbed gas storage moisture as a function of coal rank lignite subbituminous a exhibits an inverse relationship with measured gas content this result may be due to higher moisture content competing for adsorption space with coalbed gas in shallower lower rank samples shallower 600 m coal samples containing less moisture range from under to oversaturated with respect to their ch4 adsorption capacity

has arctic sea ice rapidly thinned abstract reports based on submarine sonar data have suggested arctic sea ice has thinned nearly by half in recent decades such rapid thinning is a concern for detection of global change and for arctic regional impacts including atmospheric time series ocean currents and river runoff into an ocean ice snow model show that the inferred rapid thinning was unlikely the problem stems from undersampling varying winds that readily redistribute arctic ice create a recurring pattern whereby ice shifts between the central arctic and peripheral regions especially in the canadian sector timing and tracks of the submarine surveys missed this dominant mode of variability although model derived overall thinning from the 1960s to the 1990s was less than hitherto supposed there is also indication of accelerated thinning during the early mid 1990s

on horizontal wind gradient variability from the stratosphere to the lower troposphere in the arctic 1 previous studies have demonstrated changes in vertical wind shear in recent decades with implications for upward propagating planetary waves the stratospheric polar vortex and tracer transport changes in vertical wind shear combined with horizontal gradients have also been shown to contribute to an increase in vertical gradients in tracer fields with important implications for vertical transport in order to explore the extent to which changes in vertical wind shear are reflected in changes to horizontal stirring we examine horizontal wind gradient fields from the stratosphere to the lower troposphere from 1979 to 2006 studied in particular are the spatial and temporal properties and trends for relative vorticity divergence strain and the okubo weiss criterion which monitors the competition between strain and vorticity dominated fields to illustrate how horizontal wind gradients have changed over the last several decades the results from this investigation show negative vorticity and strain anomalies during winter following 1998 associated with an increase in sudden stratospheric warmings and perturbations to the polar vortex noted in recent years spatial distributions for relative vorticity and strain fields exhibit coherent structures near the tropopause and middle stratosphere during fall and winter which are captured by the okubo weiss fields trend analyses highlight statistically significant trends in relative vorticity and okubo weiss fields during winter the results from this investigation demonstrate that statistically significant trends exist from the stratosphere to the lower troposphere it is hypothesized that the coupling from the lower troposphere to the upper atmosphere will be important in the development of our understanding of the response of sea ice concentrations to climate variability and change

development of seasonal pack ice in the beaufort sea during the winter of 1991 1992 a view from below subsea sonars moored in the beaufort sea acquired a spatial section of draft across 941 km of sea ice during the winter of 1991 1992 these observations document the development of seasonal sea ice from an open sea surface in october to an average accumulation exceeding 2 5 m draft by early april initially level ice occupied 85 of the profile but continued ridging reduced this fraction to 50 in late winter three modes of level ice were tracked that of seasonal ice whose growth was initiated at freeze up and two others created during openings of the ice field in january and in march the growth of these modes can be closely matched by calculations based on a slab model of ice formation forced using surface meteorological data initially ridge keels were small and widely spaced by midwinter an exponential dependence of keel frequency on draft was obvious e folding scale 2 16 m and the frequency and mean draft of keels had stabilized the maximum keel draft was a modest 17 4 m the low incidence of deep keels at all times is a statistically significant departure from the exponential dependence valid at lesser drafts the truncation point of the exponential relation is related to the draft of the thinnest level ice present in late winter the formation of deeper keels from thick first year ice was apparently precluded by the presence of younger thinner ice which limited the force available for ridge building through calculation of the seaward transport of ice over the sonars the total production of ice in the coastal flaw lead during 1991 1992 was determined to be about 60 of earlier indirect estimates in general the observations revealed winter ice conditions significantly less severe than those found on the periphery of the polar pack only a few tens of kilometers to the north but more so than conditions in a marginal first year ice zone at the same latitude in davis strait

on the record reduction in 1998 western arctic sea ice cover during summer 1998 record reductions in ice cover occurred in the beaufort and chukchi seas open water formed earlier than in prior years and september ice extent in this region was 25 percent less than the previous minimum for 1953 1997 seven percent of the arctic basin that had been perennially ice covered was ice free in 1998 this reduction in western arctic ice extent can be attributed in part to preconditioning by light ice cover in autumn 1997 and to atmospheric circulation patterns during the following winter through autumn that favored southerly and easterly winds such decreases in northerly winds and the associated weakening or displacement of the beaufort gyre is found to be typical of winters that precede years with below normal ice extent in the western arctic

co2 fluxes across the air sea interface in the southeastern beaufort sea ice free period 1 surface mixed layer co2 fugacities fco2 sw calculated from carbonate system parameters in the southeastern beaufort sea during the ice free period ranged from 240 to 350 atm in fall 2003 and from 175 to 515 atm in summer 2004 the surface mixed layer remains mostly undersaturated with respect to atmospheric co2 378 atm and therefore acts as a potential co2 sink throughout this period air sea co2 fluxes fco2 were first computed assuming ice free conditions and ranged from 32 4 to 8 6 mmol m 2 d 1 in fall 2003 and summer 2004 respectively then we included a reduction factor to account for ice cover ic and we computed the resulting fluxes fco2 ic in fall 2003 fco2 ic ranged from 4 7 mmol m 2 d 1 in the relatively open water of the cape bathurst polynya to 0 1 mmol m 2 d 1 in the southeastern beaufort sea limited by the presence of the multiyear sea ice in summer 2004 fco2 ic ranged from 13 1 mmol m 2 d 1 on the western mackenzie shelf to 8 6 mmol m 2 d 1 at cape bathurst the variability being ascribed to competing effects of vertical mixing temperature variations and possibly biological production on average a net sink of 2 3 3 5 mmol m 2 d 1 was estimated for the ice free period over the study area nevertheless the fco2 displays strong variability due to ice coverage freshwater input and upwelling events the potential responses direction and intensity of potential feedbacks of the carbon cycle in the study area to a changing arctic climate are discussed

a record minimum arctic sea ice extent and area in 2002 1 arctic sea ice extent and area in september 2002 reached their lowest levels recorded since 1978 these conditions likely resulted from 1 anomalous warm southerly winds in spring advecting ice poleward from the siberian coast 2 persistent low pressure and high temperatures over the arctic ocean in summer promoting ice divergence and rapid melt

investigations of newly formed sea ice in the cape bathurst polynya 2 microwave emission 1 this study examines the role of newly formed sea ice geophysical state on microwave emission coincident with sea ice geophysical sampling ship based passive microwave emission data dual polarized at 19 37 and 85 ghz were collected in the cape bathurst polynya during 18 october and 13 november 2003 using polarization ratios prs we found that bare thin ice was separable from snow covered ice thin snow equal to 0 02 0 13 m thickness is significantly correlated with the spectral gradient ratios grv 85 19 r2 0 55 p value 0 2 the relationship between atmospherically corrected r37 and bare ice thickness showed an exponential relationship very comparable to that reported by martin et al 2004 which is ascribed to the reduction of bare ice surface salinity based on both observational and modeling studies however the relationship quickly becomes invalid for even thin snow covered ice due to significant impact of thin wet liquid water fraction 0 02 0 04 snow on microwave emission our results suggest that the sea ice algorithms nasa team and nasa team 2 could underestimate total ice concentration over thin bare ice by 35 on average while both algorithms underestimate the total ice concentration by 20 over snow covered ice using pr 85 sea ice could be delineated from open water using a properly adjusted threshold value accounting for cloud or fog effects possibly with the exception of dark nilas and or bare consolidated pancakes

variability of fram strait ice flux and north atlantic oscillation we estimate the winter sea ice export through the fram strait using ice motion from satellite passive microwave data sea ice motion october may is obtained by tracking the displacement of common features in sequential 85 and 37 ghz brightness temperature fields the average winter area flux over the 18 year record 1978 1996 is 670 000 km2 7 of the area of the arctic ocean the winter area flux ranges from a minimum of 450 000 km2 in 1984 to a maximum of 906 000 km2 in 1995 the daily monthly and interannual variabilities of the ice area flux are high there is an upward trend in the ice area flux over the 18 year record the average winter volume flux over the winters of october 1990 through may 1995 is 1745 km3 ranging from a low of 1375 km3 in the 1990 flux to a high of 2791 km3 in 1994 the sea level pressure gradient across the fram strait explains more than 80 of the variance in the ice flux over the 18 year record we use the coefficients from the regression of the time series of area flux versus pressure gradient across the fram strait and ice thickness data to estimate the summer area and volume flux the average 12 month area flux and volume flux are 919 000 km2 and 2366 km3 we find a significant correlation r 0 86 between the area flux and positive phases of the north atlantic oscillation nao index over the months of december march correlation between our 5 years of volume flux estimates and the nao index gives r 0 56 during the high nao years a more intense icelandic low increases the gradient in the sea level pressure by almost 1 mbar across the fram strait thus increasing the atmospheric forcing on ice transport correlation is reduced during the negative nao years because of decreased dominance of this large scale atmospheric pattern on the sea level pressure gradient across the fram strait

investigations on physical and textural properties of arctic first year sea ice in the amundsen gulf canada november 2007 june 2008 ipy cfl system study we report sea ice temperature and bulk salinity measurements as well as textural analysis from 33 first year drift and fast ice stations sampled between november 2007 and june 2008 in the southern beaufort sea amundsen gulf canadian arctic during the international polar year circumpolar flaw lead ipy cfl system study we use this significant dataset to investigate the halo thermodynamic evolution of sea ice from growth to melt a strong desalination phase is observed over a small time window in the spring using calculated proxies of sea ice permeability brine volume fraction and of the intensity of brine convection rayleigh number we demonstrate that this phase corresponds to full depth gravity drainage initiated by a restored connectivity of the brine network with warming in the spring most stations had a textural sequence typical of arctic first year ice with granular ice overlying columnar ice unusual textural features were observed sporadically sandwiched granular ice platelet ice and draped platelet ice we suggest that turbulence in leads and double diffusion in strong brine plumes following the refreeze of cracks are plausible mechanisms for the formation of these textures

on the temporal character and regionality of the arctic oscillation decadal differences between the 1990s and 1980s in winter jfm sea level pressure and 300 mb zonal winds have an arctic centered character with nearly equal contributions from the atlantic and pacific sectors in contrast the differences between positive and negative arctic oscillation ao composites defined from monthly values of principal components from the same period have similar magnitudes in the pacific and arctic but have an additional large north atlantic oscillation nao signature in the atlantic sector thus arctic changes on decadal scales are more symmetric with the pole than suggested by the standard ao index definition change point analysis of the ao shows that a shift in value near 1989 is an alternate hypothesis to a linear trend analysis of zonal and meridional winds by longitudinal sectors shows the importance of the standing wave pattern in interpreting the ao which supplements the view of the ao as a simple zonal average annular mode

response of sea ice to the arctic oscillation abstract data collected by the international arctic buoy programme from 1979 to 1998 are analyzed to obtain statistics of sea level pressure slp and sea ice motion sim the annual and seasonal mean fields agree with those obtained in previous studies of arctic climatology the data show a 3 hpa decrease in decadal mean slp over the central arctic ocean between 1979 88 and 1989 98 this decrease in slp drives a cyclonic trend in sim which resembles the structure of the arctic oscillation ao regression maps of sim during the wintertime january march ao index show 1 an increase in ice advection away from the coast of the east siberian and laptev seas which should have the effect of producing more new thin ice in the coastal flaw leads 2 a decrease in ice advection from the western arctic into the eastern arctic and 3 a slight increase in ice advection out of the arctic through fram strait taken together these changes suggest that at least part of the thinning of sea ice recently observed ov

deterioration of perennial sea ice in the beaufort gyre from 2003 to 2012 and its impact on the oceanic freshwater cycle time series of ice draft from 2003 to 2012 from moored sonar data are used to investigate variability and describe the reduction of the perennial sea ice cover in the beaufort gyre bg culminating in the extreme minimum in 2012 negative trends in median ice drafts and most ice fractions are observed while open water and thinnest ice fractions 0 3 m have increased attesting to the ablation or removal of the older sea ice from the bg over the 9 year period monthly anomalies indicate a shift occurred toward thinner ice after 2007 in which the thicker ice evident at the northern stations was reduced differences in the ice characteristics between all of the stations also diminished so that the ice cover throughout the region became statistically homogenous the moored data are used in a relationship with satellite radiometer data to estimate ice volume changes throughout the bg summer solid fresh water content decreased drastically in consecutive years from 730 km3 in 2006 to 570 km3 in 2007 and to 240 km3 in 2008 after a short rebound solid fresh water fell below 220 km3 in 2012 meanwhile hydrographic data indicate that liquid fresh water in the bg in summer increased 5410 km3 from 2003 to 2010 and decreased at least 210 km3 by 2012 the reduction of both solid and liquid fresh water components indicates a net export of approximately 320 km3 of fresh water from the region occurred between 2010 and 2012 suggesting that the anticyclonic atmosphere ocean circulation has weakened

meteorological forcing of sea ice concentrations in the southern beaufort sea over the period 1979 to 2000 1 northern hemisphere sea ice areal extent and perhaps thickness have shown a detectable reduction over the past several decades this situation is particularly apparent in the southern beaufort sea the region encompassing the mackenzie shelf the cape bathurst polynya and the canada basin mobile pack ice all occur in a region referred to here as the canadian arctic shelf exchange study area cases in this paper we present results from an analysis of atmosphere sea ice and ocean coupling over the period 1979 to 2000 as a means of setting a physical science context for the cases research network operating over the period 2001 2005 results show that the cape bathurst polynya complex can be considered as a recurrent polynya particularly the flaw leads associated with the early opening of the polynya the polynya appears to be a consequence of the beaufort sea gyre acting like an ice bridge and a series of flaw leads creating conditions conducive to oceanic upwelling the sea ice average areal extent has been decreasing in this region over the period 1979 to 2000 large regional reductions are found i north of the yukon and alaska coasts in the region between the canada basin pack ice and the landfast sea ice and 2 at the eastern limit of the cape bathurst polynya in amundsen gulf the meteorological forcing of sea ice anomalies occurs through a full range of timescales and space scales at hemispheric scales a statistical cross correlation analysis between weekly sea ice concentration anomalies and the arctic oscillation accounts for a maximum of about 25 percent of the explained variance and show a surprising spatial coherence in correlation magnitudes both within the study area and northward along the canadian archipelago coast at local scales positive and negative concentration anomaly periods can be explained through local scale advective processes associated with regional scale sea level pressure 500 hpa geopotential heights and surface temperature anomalies

interannual variability of arctic landfast ice between 1976 and 2007 abstractanalysis of weekly sea ice charts produced by the u s national ice center from 1976 to 2007 indicates large interannual variations in the averaged winter landfast ice extent around the arctic basin during the 32 yr period of the record landfast ice cover was relatively extensive from the early to mid 1980s but since then has declined in many coastal regions of the arctic particularly after the early 1990s while the barents baltic and bering seas show increases in landfast ice area the overall change for the northern hemisphere is negative about 12 27 2 8 103 km2 yr 1 or 7 1 5 decade 1 relative to the long term mean except in a few coastal regions the seasonal duration of landfast ice is shorter overall particularly in the laptev east siberian and chukchi seas the decreased winter landfast ice extent is associated with some notable changes in ice growth and melt patterns in particular the slowed landfast ice expansion during fall and early winter since 1990 the observed

geology of oil shale deposits within the narrows graben queensland australia discussion investigation of the organic matter in oil shales from the narrows graben queensland and other australian tertiary oil shales has shown that most of the organic matter is derived from planktonic algae including pediastrum these oil shales are termed lamosites the presence of pediastrum in australian lamosites indicates that these oil shales were deposited in fresh to brackish lacustrine waters which were probably shallow and possibly adjacent to the sea occurrence of pediastrum in lamosites from yugoslavia thailand china and the us indicates that pediastrum was probably of widespread occurrence during the tertiary and may be an important constituent of many other lamosites of tertiary age 16 references 6 figures 1 table

thinning of the arctic sea ice cover comparison of sea ice draft data acquired on submarine cruises between 1993 and 1997 with similar data acquired between 1958 and 1976 indicates that the mean ice draft at the end of the melt season has decreased by about 1 3 m in most of the deep water portion of the arctic ocean from 3 1 m in 1958 1976 to 1 8 m in the 1990s the decrease is greater in the central and eastern arctic than in the beaufort and chukchi seas preliminary evidence is that the ice cover has continued to become thinner in some regions during the 1990s

seismic emission activity of earth s crust in northern kanto japan abstract by using the semblance analysis of seismic noise prehistory of local earthquakes recorded by a dense seismic array we reconstruct the image of distributed sources of weak seismic radiation beneath the earth s surface array observations were carried out in the nikko area northern kanto japan in 1993 by joint seismic observation team the array consists of 195 three component seismometers distributed along perpendicular profiles whose array diameters are 7 km from the analysis of data several active volumes in the upper crust were identified and new features of seismic emission discovered a joint analysis of the coda and seismic noise shows that a mid crustal magma body that was identified before by reflection analysis is both a scattering region and a source of seismic emission another large active volume is visible to the east of the array at depths of 2 15 km it coincides with a known low velocity and high attenuation anomaly this emission region corresponds to an area of large earthquakes

modeling landfast sea ice by adding tensile strength landfast ice is sea ice that forms and remains fixed along a coast where it is either attached to the shore or held between shoals or grounded icebergs the current generation of sea ice models is not capable of reproducing certain aspects of landfast ice behavior for example the persistence of landfast sea ice under the effect of offshore winds the authors develop a landfast sea ice model by adding tensile strength to the viscous plastic as well as two versions of the elastic viscous plastic sea ice rheologies one dimensional implementations of these rheologies are used to explore the ability of coastal sea ice to resist offshore winds over extended times while all modified rheologies are capable of maintaining landfast ice like structures in the model only the viscous plastic rheology fulfills theoretical expectations the elastic viscous plastic rheologies show initial elastic waves that weaken the ice and thus reduce its capacity of maintaining landfast ice further special care has to be taken when implementing the most commonly used version of the elastic viscous plastic rheology because the standard set of parameters is not adequate for landfast sea ice modeling

exchange of sea ice between the arctic ocean and the canadian arctic archipelago 1 first estimates of sea ice exchange between the arctic ocean and the canadian arctic archipelago caa are obtained using six years 1997 2002 of radarsat ice motion over the period the mean annual flux of sea ice area from the amundsen gulf ag m clure strait ms and queen elizabeth islands qei are 85 26 103 20 24 103 and 8 6 103 km2 positive negative sign indicates arctic outflow inflow overall net sea ice area is exported from the caa rough estimates suggest a mean annual volume flux of 102 km3 into the canada basin ice types are largely seasonal near the ag flux gate mixed seasonal and multiyear at the ms gate and primarily multiyear at the qei gates sea ice at the qei flux gates remains land fast for most of the year cross strait gradient in sea level pressure explains more than 50 of the variance in the area flux at these passages the role of ice exchange during the anomalous decrease in multiyear ice coverage in the sverdrup basin during september 1998 is examined

mineralogical geochemical and magnetic signatures of surface sediments from the canadian beaufort shelf and amundsen gulf canadian arctic mineralogical geochemical magnetic and siliciclastic grain size signatures of 34 surface sediment samples from the mackenzie beaufort sea slope and amundsen gulf were studied in order to better constrain the redox status detrital particle provenance and sediment dynamics in the western canadian arctic redox sensitive elements mn fe v cr zn indicate that modern sedimentary deposition within the mackenzie beaufort sea slope and amundsen gulf took place under oxic bottom water conditions with more turbulent mixing conditions and thus a well oxygenated water column prevailing within the amundsen gulf the analytical data obtained combined with multivariate statistical notably principal component and fuzzy c means clustering analyses and spatial analyses allowed the division of the study area into four provinces with distinct sedimentary compositions 1 the mackenzie trough canadian beaufort shelf with high phyllosilicate fe oxide magnetite and al k ti fe cr v zn p contents 2 southwestern banks island characterized by high dolomite k feldspar and ca mg loi contents 3 the central amundsen gulf a transitional zone typified by intermediate phyllosilicate magnetite k feldspar dolomite and al k ti fe mn v zn sr ca mg loi contents and 4 mud volcanoes on the canadian beaufort shelf distinguished by poorly sorted coarse silt with high quartz plagioclase authigenic carbonate and si zr contents as well as high magnetic susceptibility our results also confirm that the present day sedimentary dynamics on the canadian beaufort shelf is mainly controlled by sediment supply from the mackenzie river overall these insights provide a basis for future studies using mineralogical geochemical and magnetic signatures of canadian arctic sediments in order to reconstruct past variations in sediment inputs and transport pathways related to late quaternary climate and oceanographic changes keywords mineralogy elemental geochemistry magnetic properties surface sediment sediment provenance redox condition canadian beaufort shelf amundsen gulf

lithospheric studies based on array analysis of p coda and microseisms abstract a simple coherence measure the semblance coefficient has been used to sample the lithosphere beneath the norsar array in terms of its ability to produce coherent seismic energy the data set is comprised of two samples of teleseismic p coda waves south of honshu and hindu kush events and two samples of microseismic noise data with duration of about one hour each concerning the constitution of the earth structure there are two possibilities for coherent energy to be present in noise like wavefields the first is tied to scattering effects and the second may be brought about by seismic emission effects the emissive component represents the seismic response of the medium to variations in the background stress field which may arise from various sources passing seismic waves body or surface free oscillations of the earth tides an abnormal level of heat flow or geodynamic processes in general the presence of a well known source of seismic signal hunderfossen dam in the vicinity of norsar area provided an opportunity to test the data processing algorithm results obtained for two independent microseismic data samples point to the same location in close vicinity to the dam for p coda data the signal energy from the upper mantle areas as indicated by the maximum of semblance measure values at the depth around 116 km reaches about 3 8 and 5 of the total p coda energy for honshu and hindu kush events respectively for microseismic noise data this value is about 1 at a depth around 100 km comparison with the results of holographic studies supports the assumption that in the case of microseismic data the detected signal energy is of emissive nature while for p coda data we need more coda samples to make a sound judgement about the nature scattering or emission of the detected signals

bituminite a tem view abstract an illinois coal high volatile bituminous b of carboniferous age containing typical bituminite has been examined by transmission electron microscopy tem to supplement observations with the light microscope with tem the bituminite has a fine fairly regular structure including voids of a characteristic shape this structure is almost certainly inherited from a botanical precursor and is thought to represent much altered remains of former colonies of algae probably green algae the present remains contain abundant lipid rich globules and probably also include matter of algal and bacterial origin which cannot be resolved even at tem resolutions

manifestation of earth deformation processes by high frequency seismic noise characteristics abstract during recent years special investigations of high frequency seismic noise hfsn have been conducted in order to study the nature of temporal regularities of this process some correlation between hfsn level and slow changes of stress field have been observed under different geological conditions these phenomena were interpreted as being due to the presence of a seismic emission component in hfsn which is characterized by a very strong tensosensitivity i e sensitivity to the stress changes later observations of hfsn carried out at different places using highly sensitive resonant seismometers show that a modulation phenomenon i e correlation between hfsn changes and earth s tides has been seen with a different degree of confidence both in time and space this result is explained by the spatial variations in emission activity it is thought that hfsn is influenced by different kinds of geodynamic processes which change the tensosensitivity and the emission activity with time and with the presence of external seismic noises detailed inspection of hfsn behaviour shows that its response to external action is more complex than was previously thought according to observations held on a russian platform the seismic emission level is found to be modulated by changes in the intensity of 4 6 s microseisms connected with the baltic sea storms in the ashkhabad region where no strong effects of external sources are known hfsn amplitude correlates with changes of tilt caused by moon solar tides temporal change of correlation between these processes is observed well observations detected noticeable variations of the hfsn intensity with depth and the dependence of intensity and spectral composition on structure and composition of rocks this is direct proof of the endogenic nature of observed hfsn periodic changes of hfsn level observed after the strong gasli earthquake of march 19 1984 m 7 2 near the city of ashkhabad are discussed as a new self excitation type of hfsn two opposite points of view on the nature of hfsn either as telluric processes highly sensitive to stress conditions or as a noise which is not sensitive to the stress conditions are discussed and explained by both the large variance of hfsn behaviour and by the methods and conditions of observation

divergent patterns of recent sea ice cover across the bering chukchi and beaufort seas of the pacific arctic region abstract over the past three decades of the observed satellite record there have been significant changes in sea ice cover across the bering chukchi and beaufort seas of the pacific arctic region par satellite data reveal that patterns in sea ice cover have been spatially heterogeneous with significant declines in the chukchi and beaufort seas yet more complex multi year variability in the bering sea south of st lawrence island these patterns in the chukchi and beaufort seas have intensified since 2000 indicating a regime shift in sea ice cover across the northern portion of the par in particular satellite data over 1979 2012 reveal localized decreases in sea ice presence of up to 1 64 days year canada basin and 1 24 days year beaufort sea which accelerated to up to 6 57 days year canada basin and 12 84 days year beaufort sea over the 2000 2012 time period in contrast sea ice in the bering sea shows more complex multi year variability with localized increases in sea ice presence of up to 8 41 days year since 2000 the observed increases in sea ice cover since 2000 in the southern bering sea shelf region are observed in wintertime whereas sea ice losses in the canada basin and beaufort sea have occurred during summer we further compare sea ice variability across the region with the national centers for environmental prediction ncep north american regional reanalysis narr wind and air temperature fields to determine the extent to which this recent variability is driven by thermal vs wind driven processes results suggest that for these localized areas that are experiencing the most rapid shifts in sea ice cover those in the beaufort sea are primarily wind driven those offshore in the canada basin are primarily thermally driven and those in the bering sea are influenced by elements of both sea ice variability and its drivers across the par provides critical insight into the forcing effects of recent shifts in climate and its likely ultimate profound impacts on ecosystem productivity across all trophic levels

impact of sea ice processes on the carbonate system and ocean acidification at the ice water interface of the amundsen gulf arctic ocean 1 from sea ice formation in november 2007 to onset of ice melt in may 2008 we studied the carbonate system in first year arctic sea ice focusing on the impact of calciumcarbonate caco3 saturation states of aragonite xar and calcite xca at the ice water interface uiw based on total inorganic carbon ct and total alkalinity at and derived ph co2 carbonate ion co3 22 concentrations and x we investigated the major drivers such as brine rejection caco3 precipitation bacterial respiration primary production and co2 gas flux in sea ice brine frost flowers and uiw we estimated large variability in seaice ct at the top mid and bottom ice changes due to caco3 and co2 gas flux had large impact on ct in the whole ice core from march to may bacterial respiration was important at the bottom ice during all months and primary production in may it was evident that the sea ice processes had large impact on uiw resulting in a five times larger seasonal amplitude of the carbonate system relative to the upper 20 m during ice formation co2 increased by 30 mmol kg 21 co 3 22 decreased by 50 mmol kg 21 and the xar decreased by 0 8 in the uiw due to co2 enriched brine from solid caco3 conversely during ice melt co3 22 increased by 90 mmol kg 21 in the uiw and x increased by 1 4 between march and may likely due to caco3 dissolution and primary production we estimated that increased ice melt would lead to enhanced oceanic uptake of inorganic carbon to the surface layer

the arctic oscillation signature in the wintertime geopotential height and temperature fields the leading empirical orthogonal function of the wintertime sea level pressure field is more strongly coupled to surface air temperature fluctuations over the eurasian continent than the north atlantic oscillation nao it resembles the nao in many respects but its primary center of action covers more of the arctic giving it a more zonally symmetric appearance coupled to strong fluctuations at the 50 hpa level on the intraseasonal interannual and interdecadal time scales this arctic oscillation ao can be interpreted as the surface signature of modulations in the strength of the polar vortex aloft it is proposed that the zonally asymmetric surface air temperature and mid tropospheric circulation anomalies observed in association with the ao may be secondary baroclinic features induced by the land sea contrasts the same modal structure is mirrored in the pronounced trends in winter and springtime surface air temperature sea level pressure and 50 hpa height over the past 30 years parts of eurasia have warmed by as much as several k sea level pressure over parts of the arctic has fallen by 4 hpa and the core of the lower stratospheric polar vortex has cooled by several k these trends can be interpreted as the development of a systematic bias in one of the atmosphere s dominant naturally occurring modes of variability

seasonal variability of water mass distribution in the southeastern beaufort sea determined by total alkalinity and δ18o 1 we examined the seasonal variability of water mass distributions in the southeastern beaufort sea from data collected between september 2003 and august 2004 salinity total alkalinity ta and isotopic composition 18o of seawater were used together as tracers of freshwater input i e meteoric water and sea ice meltwater we used an optimum multiparameter analysis to identify the different water masses including the mackenzie river sea ice melt sim winter polar mixed layer pml upper halocline water uhw with core salinity of 33 1 psu pacific origin and atlantic water computed values of co2 fugacity in seawater fco2 sw show that the surface mixed layer sml remains mostly undersaturated 328 55 atm n 552 with respect to the average atmospheric co2 concentration 380 5 atm over the study period the influence of the mackenzie river fco2 sw 500 atm was relatively small in the southeastern beaufort sea and significant fractions were only observed on the inner mackenzie shelf the contribution of sea ice melt fco2 sw 600 atm was usually located between 120 and 180 m depth but could contribute to the sml during wind driven upwelling events in summer and autumn and during brine driven eddies in winter

on sea ice concentration anomaly coherence in the southern beaufort sea 1 the circumpolar flaw lead polynya system is a region of enhanced biological productivity and for significant portions of the annual cycle dominates the exchange of energy and mass across the ocean sea ice atmosphere osa interface we investigate the nature of sea ice concentration sic anomalies for spatial and temporal statistical persistence within a portion of this flaw lead system we find such a structure in the shelf break zone between amundsen gulf and the canada basin ncep ncar reanalysis data is used to determine the potential roles of oceanic and atmospheric forcing in creating and maintaining this observed coherence in the sic anomalies results suggest that the coherence pattern is consistent over the instrumental record 1979 to 2000 although it changes in shape and extent between years the forcing mechanisms creating this coherence in sic anomalies appear to be tied to surface wind driven upwelling in the shelf break areas of the southern beaufort sea sbs