benthic foraminiferal recovery in the oslofjord norway responses to capping and re oxygenation abstract since 2001 the semi enclosed bekkelag basin inner oslofjord has been re oxygenated following decades of predominantly anoxic conditions additionally in 2007 parts of the polluted organic rich sediments in the basin were capped with uncontaminated post glacial clay this offered a unique opportunity to monitor the response recovery and colonization of the benthic community to re oxygenation and capping with uncontaminated sediments two sites 165 m apart at 50 m water depth in the bekkelag basin were regularly sampled for benthic foraminiferal and geochemical analyses between march 2008 and september 2010 one site rc5 capped was located in the middle and one rc9 re oxygenated uncapped just outside the capped area at the beginning of the study period the former had been exposed to colonization for one year and the latter for seven years maximum abundance of benthic foraminifera occurred in the surface 0 5 cm of sediment at both sites 60 occurred in the surface 0 1 cm and the majority of these were small 63 125 m forms the same taxa i e stainforthia fusiformis bulimina marginata textularia earlandi organic walled allogromiids were common at both sites indicating that the colonizers had rapidly immigrated from neighboring environments however their abundance showed pronounced differences between sites the dominance was lower and the species richness was significantly higher at the capped compared to the uncapped site throughout the study period these faunal characteristics probably reflect the fundamentally different environmental properties of the capping clay versus those of the formerly anoxic sediments nevertheless the absolute abundance increased at both sites and the assemblage compositions converged with time these results show that benthic foraminifera are well suited for monitoring ecological recovery and that colonization at the uncapped site where recovery was due to re oxygenation was slower than at the capped site

recent environmental changes recorded in anoxic barsnesfjord sediments western norway abstract four high quality gravity cores and five box cores up to 2 3 m long from the land locked silled and anoxic barsnesfjord in western norway contained three different sediment sequences these were alternating thick dark and light layers fine scaled laminated sections and grayish brownish layers dominated by minerogenic grains accurate sedimentation rates over the last 150 years were determined using three different techniques 137 cs dating occurrence of historically documented slide slump events and counting of seasonal sediment layers bulk sediment and organic carbon accumulation rates in the outer and inner fjord basin decreased by over 30 when values of the last century pre 1904 are compared with those of this century 1904 1986 this significant change is attributed to the damming of the hafslovatn in 1904 no significant change in these values was observed after regulation of the veitastrondsvatn in 1982 and after the 2nd damming of the hafslovatn in connection with the construction of the aroy electrical power plant in 1983 zn and cu accumulation over the same time periods remained constant

the minch palaeo ice stream nw sector of the british irish ice sheet geophysical data from the uk continental shelf off nw scotland reveal strongly parallel subglacial bedforms on the sea bed field mapping on the adjacent landmass has identified closely spaced bedrock megagrooves and highly elongate drumlinoid forms all these mega scale glacial lineations probably formed beneath the same fast flowing zone of the last british irish ice sheet the minch palaeo ice stream this ice stream drained the nw sector of the british irish ice sheet during the late devensian glaciation marine isotope stage 2 and terminated near the edge of the continental shelf the size of the adjacent trough mouth sula sgeir fan and the presence of buried mega scale glacial lineations within the quaternary stratigraphic record imply that fast ice sheet flow in the minch has been a feature of several mid to late pleistocene glaciations

marine climate variability during the last millennium the loch sunart record scotland uk abstract the first decadal scale reconstruction of british coastal temperature anomalies spanning the last millennium is presented from a sea loch fjord basin loch sunart nw scotland based on modern observation and the results of previous numerical modeling of fjord circulation benthic foraminiferal oxygen isotope records are interpreted as a record of summer temperature a significant climate transition apparently driven by large scale reorganization of northern hemisphere atmospheric circulation occurs in the record around ad 1400 an abrupt but relatively short lived climate warming occurs between ad 1540 1610 when the bottom water temperature anomalies are 1 1 c above the long term average which is warmer than most of the 20th century and the late medieval warm period a long term cooling occurs throughout the little ice age culminating in the coldest recorded temperature anomalies between the late 1920s and 1940s the warmest reconstructed temperatures of the past millennium occurred in the last 5 years of the record which ends in 2006 a replicated post ad 1900 shift in benthic foraminiferal 13 c of ca 0 6 provides evidence of the oceanic 13 c suess effect this feature provides an independent test of the age model and demonstrates the value of benthic foraminifera as palaeo proxies in the loch sunart record

organic carbon burial in fjords terrestrial versus marine inputs abstract fjords have been identified as sites of enhanced organic carbon oc burial and may play an important role in regulating climate change on glacial interglacial timescales understanding sediment processes and sources of sedimentary oc are necessary to better constrain oc burial in fjords in this study we use fiordland new zealand as a case study and present data on surface sediments sediment down cores and terrestrial end members to examine dynamics of sediments and the sources of oc in fjord sediments sediment cores showed evidence of multiple particle sources frequent bioturbation and mass wasting events a multi proxy approach stable isotopes lignin phenols and fatty acids allowed for separation of marine soil and vascular plant oc in surface sediments the relationship between mass accumulation rate mar and oc contents in fjord surface sediments suggested that mineral dilution is important in controlling oc content on a global scale but is less important for specific regions e g new zealand the inconsistency of oc budgets calculated by using mar weighted oc and oc accumulation rates ar 6 vs 21 31 tg oc yr 1 suggested that sediment flux in fjords was likely underestimated by using end member models we propose that 55 to 62 of total oc buried in fjords is terrestrially derived and accounts for 17 12 of the octerr buried in all marine sediments the strong correlation between mar and oc ar indicated that oc flux will likely decrease in fjords in the future with global warming due to decrease in sediment flux caused by glacier denudation

interlaminated ice proximal glacimarine sediments in muir inlet alaska muir inlet in glacier bay alaska is a glacial fjord receiving a tremendous volume of sediment annually the rate of sediment accumulation is greatest proximal to muir glacier about 9 m yr 1 and decreases away from the glacier the primary sediment sources are meltwater streams discharging at subglacial and ice marginal positions to form overflows interflows and underflows continuous turbidity currents overflows and interflows interact with diurnal tidal currents and their volume and sediment concentration varies diurnally and annually with meltwater discharge these effects produce cyclic deposits of a thin fine grained sand or silt lamina that grades normally to a thicker poorly to very poorly sorted mud lamina this lamina couplet is termed a cyclopel underflows are suggested to occur in this glacimarine environment because of conditions unique to subglacial fluvial systems underflow deposits occur only in proximal positions 0 5 km from glacier face and are coarse grained reverse to normal graded and exhibit an increase in sorting and sand content up layer ice rafted debris identified as particles 177 m is ubiquitous though low 5 by weight and occurs as isolated particles frozen pellets or as lenses that in cores may have a lamina appearance proximally ice rafted debris is difficult to identify because proximal sediment is often as coarse grained deposited sediment may be reworked by tidal currents and sediment gravity flows depositional processes operating in muir inlet produce interlaminated sand silt clay that characterizes sediment proximal to a glacier and fines seaward to mud sediment is classified into one of three sediment types 1 1 type i sediment is very fine grained mean 8 65 7 17 o low in sand 0 1 11 2 and very poorly to poorly sorted it is the dominant sediment type in muir inlet and is transported by plumes and deposited by suspension settling 2 2 type ii sediment is fine to coarse grained mean 6 70 3 12 o low to high in sand 5 1 86 6 and very poorly to moderately sorted it represents reworked sediment proximal plume deposits or coarse grained laminae of cyclopels 3 3 type iii sediment is coarse grained mean 3 89 2 38 o high in sand 58 0 100 0 and poorly to well sorted it is deposited by sediment gravity flows or underflows

erosion of sognefjord norway sognefjord is formed by a combination of exploitation of rock structure and subaerial and subglacial processes the fjord system follows zones of rock structural weakness above sea level the landforms are due mainly to subaerial processes and somewhat surprisingly not to glacial activity removal of erosive products and deepening of the fjord below sea level is due to glacial erosion

synchronizing ice cores from the renland and agassiz ice caps to the greenland ice core chronology 1 four ice cores from the agassiz ice cap in the canadian high arctic and one ice core from the renland ice cap in eastern greenland have been synchronized to the greenland ice core chronology 2005 gicc05 which is based on annual layer counts in the dye 3 grip and ngrip ice cores volcanic reference horizons seen in electrical conductivity measurements ecm have been used to carry out the synchronization throughout the holocene the agassiz ice cores have been matched to the ngrip ice core ecm signal while the renland core has been matched to the grip ice core ecm signal thus tying the cores to gicc05 furthermore it has been possible to synchronize the renland ice core to ngrip gicc05 in the glacial period back to 60 000 years b2k years before a d 2000 on the basis of a matching of transitions between stadials and interstadials this work brings the total number of ice core records that have been rigorously tied to the gicc05 timescale up to nine renland annual layer thicknesses are increasing with depth during the period from 7 to 8 5 ka b2k a highly unusual observation only matched by a similar thickness increase in the glacial section of the renland core some 60 ka ago annual layer thicknesses in the agassiz ice cores point to a well developed raymond bump in the agassiz ice cap

alkenones alkenoates and organic matter in coastal environments of nw scotland assessment of potential application for sea level reconstruction reconstruction of late quaternary sea level history in areas of glacioisostatic uplift often relies on sediment archives from coastal isolation basins natural coastal rock depressions previously isolated from or connected to the sea at different times proxy indicators for marine brackish or lacustrine conditions combined with precise dating can constrain the time when the sea crossed the sill threshold and isolated or connected the basin the utility of isolation basins in investigations of sea level change is well known but investigations have been mostly limited to microfossil proxies the application of which can be limited by preservation and nonanalog problems here we investigate the potential of long chain alkenones alkenoates and bulk organic parameters toc corg n for reconstructing past sea level changes in isolation basins in nw scotland we analyze organic biomarkers and bulk parameters from both modern basins at different stages of isolation from the sea and fossil basins with sea level histories reconstructed from established proxies logit regression analysis was employed to find which of the biomarker metrics or bulk organic measurements could reliably characterize the sediment samples in terms of a marine brackish or isolated lacustrine origin the results suggested a good efficiency for the alkenone index c37 4 at predicting the depositional origin of the sediments this study suggests that alkenones could be used as a novel proxy for sea level change in fossil isolation basins especially when microfossil preservation is poor

geochemical and sedimentological considerations of a permanently anoxic fjord framvaren south norway abstract framvaren a fjord in south norway is an example of extreme anoxia due to the geomorphological features sill depth 2 m basin depth 180 m the postglacial history of framvaren is outlined emphasizing the preservation of environmental changes in the properties of the water and the sediments high levels of hydrogen sulfide in the water 170 180 ml l 1 or 7 8 mm h 2 s dense populations of photosynthetic bacteria at the redox boundary total number 3 10 6 ml 1 metal sulfide formation in the anoxic water e g framboidal pyrite and zinc sulfide and organic rich bottom sediments with high metal content e g 1000 ppm zn are typical examples the rate of sedimentation is estimated in three independent ways suggesting an average annual flux of 100 g m 2 yr 1 in the central basin of framvaren fluxes of organic matter and zinc to the sediments are calculated and compared with potential sources

sources sinks and subsidies terrestrial carbon storage in mid latitude fjords this work was supported by the natural environment research council grant number ne l501852 1 with additional support from the nerc life science mass spectrometry facility ceh l 098 11 2015 and the nerc geophysical equipment facility nggfsc minor loan 1031

8000 year marine record of climate variability and fjord dynamics from southern greenland abstract holocene sediment records of glacio marine environmental and climatic changes from ikersuaq fjord and narsaq sound in southern greenland have been studied the ikersuaq fjord record representing the last c 500 years is dominated by turbidite sedimentation and very high sedimentations rates of up to 1 cm yr the adjacent narsaq sound site on the other hand represents a continuous and more slowly accumulating sedimentation record of the last c 8000 years the narsaq record reveals changes in position and melting rates of glacier termini of the nearby greenland ice sheet from the holocene thermal optimum period terminating at about 5 0 ka to the neoglaciation period during the late holocene from 8 0 ka to 4 8 ka ice rafted debris ird influx progressively became reduced supporting a landward retraction of glacier termini neoglaciation of the region appears to have been initiated at about 4 8 ka with a culmination of ird rain at about 4 6 ka 3 6 ka 2 2 ka 1 0 ka 0 7 ka and 0 5 ka and onward some of these ird events appear to be associated with enhanced melting and glacier instability during warming episodes however at the transition to the little ice age at about 1450 years ad a marked increase in ird influx took place the bottom water of narsaq sound appears to have been dominated by modified irminger water atlantic during most of the holocene bottom current flow was quite sluggish before 3 2 ka whereas the late holocene period appears to have been characterised by three pronounced episodes of increased bottom current velocity and increased calcareous benthic foraminifera productivity the long term climate pattern in the narsaq sound record follows climate changes consistent with patterns of east greenland current variability which is partly related to dominant north atlantic oscillation forcing of wind and ice drift patterns

time gcm results for the quasi two day wave to understand how the quasi two day wave qtdw interacts with the mean flow and migrating tides we perturbed the lower boundary of the national center for atmospheric research thermosphere ionosphere mesosphere electrodynamics general circulation model time gcm to excite the qtdw results from our initial model runs computed for a perpetual january 15th show wave amplitudes in wind and temperature that are in qualitative agreement with previous model results and observations the wave period and amplitude change over the duration of the model run and it is expected that this results from changes in the zonal mean zonal winds evidence supporting nonlinear interactions between the qtdw and the migrating tides is presented

a two millennium dinoflagellate cyst record from gullmar fjord a swedish skagerrak sill fjord abstract gullmar fjord a sill fjord on the skagerrak coast of western sweden contains a valuable sedimentary archive for the last 2500 years this archive encompasses a temporal record from the roman warm period the dark ages the medieval warm period the little ice age and into the modern warm period a high resolution dinoflagellate cyst analysis has been completed on this archive using material from two cores taken from the deepest part of the fjord alsback deep the recovered dinoflagellate cysts have provided a quantitative temporal record that has been used to construct a dinoflagellate cyst spectrum and has been subjected to both q mode cluster analysis and cabfac factor analysis with varimax rotation in addition the heterotrophic ratio and both the thermophilic and cryophilic ratios have been calculated to assist with the interpretation of the results well preserved and diverse dinoflagellate cyst assemblages have been recovered throughout the sedimentary sequence and have been used to explore surface water conditions within the fjord over this time interval although a clear link is observed between the cyst assemblages and the climate phases of the subatlantic established from previous stable isotope work there was little change in the cyst populations and indeed they reflect the known modern cyst floras however a major change was seen in the incoming of gymnodinium nolleri during the dark age and its reduction to a relict species towards the end of the little ice age comparisons to other published work confirm the regional nature of this dinoflagellate cyst event but its ecological preferences remain enigmatic a second major change was also recognised around the late 1960s early 1970s and was associated with differences in nutrient availability from either a diminution in upwelling as the nao changed from a negative phase to a positive or from marine pollution or a combination of both otherwise the dinoflagellate cyst assemblages can be grouped using the factor analysis into f1 protoperidinium spp indet round brown cysts f2 g nolleri and f3 lingulodinium polyedrum and protoceratium reticulatum the cluster analysis shows a similar subdivision into units closely associated with the recognised climate phases of the subatlantic possible climate environments have been explored but because of the relatively minor variations in the assemblages and the lack of autecological information only relatively small scale changes were recognised except for the clear but complex nature of the recent warm period

generation of secondary waves arising from nonlinear interaction between the quasi 2 day wave and the migrating diurnal tide theory and past observations have provided evidence that atmospheric tides and other global scale waves interact nonlinearly to produce additional secondary waves throughout the space atmosphere interaction region however few studies have investigated the generation region of nonlinearly generated secondary waves and as a result the manifestation and impacts of these waves are still poorly understood this study focuses on the nonlinear interaction between the quasi 2 day wave 2dayw3 and the migrating diurnal tide dw1 two of the largest global scale waves in the atmosphere the fundamental goals of this effort are to characterize the forcing region of the secondary waves and to understand how it relates to their manifestation on a global scale first the fast fourier synoptic mapping method is applied to thermosphere ionosphere mesosphere energetics and dynamics sounding of the atmosphere using broadband emission radiometry satellite observations to provide new evidence of secondary waves these results show that secondary waves are only significant above 80 km the nonlinear forcing for each secondary wave is then computed by extracting short term primary wave information from a reanalysis model the estimated nonlinear forcing quantities are used to force a linearized tidal model in order to calculate numerical secondary wave responses model results show that the secondary waves are significant from the upper mesosphere to the middle thermosphere highlighting the implications for the atmosphere space weather coupling the study also concludes that the secondary wave response is most sensitive to the nonlinear forcing occurring in the lower and middle mesosphere and not coincident with the regions of strongest nonlinear forcing

verification of large scale rapid transport in the lower thermosphere tracking the exhaust plume of sts 107 from launch to the antarctic 1 new analysis of the doppler shift of o2 airglow spectra recorded by the timed doppler interferometer tidi and the high resolution doppler imager hrdi have provided conclusive evidence that the shuttle main engine exhaust plume generated in the lower thermosphere by the launch of sts 107 and imaged by the global ultraviolet imager guvi instrument on timed was transported to the antarctic in 80 h supporting a key inference from the initial study by stevens et al 2005 these new results were aided by improved knowledge of the effects of instrumental and satellite artifacts imposed on the doppler spectra sts 107 launched on 16 january 2003 and the neutral wind near its launch trajectory and nearby volume was sampled within minutes by tidi these initial observations suggested that the northernmost end of the shuttle s exhaust plume would move northeast and that the southern end would move southeast motions that were identified in imagery acquired during the next orbit of timed the direction and magnitude of plume motion inferred from guvi images obtained 12 26 and 50 h after launch were again confirmed by tidi and hrdi the appearance of the plume over the antarctic 80 h after launch inferred from earlier work by the appearance of iron ablated from the shuttle s main engines was consistent with neutral winds measured by the satellite doppler instruments over the antarctic the transport of the plume from the coast of florida to the antarctic was aided by the favorable phase and strong amplitude of a 2 day planetary wave of wave number three in the southern hemisphere on 18 january 2003 the existence of the 2 day wave was deduced from zonally averaged and combined tidi and hrdi neutral wind observations we conclude that the existence of strong and sustained winds in the mlt significantly greater than expected from empirical and theoretical models is indisputable and provides compelling evidence supporting the global scale nature of thermospheric winds with magnitude greater than 100 m s observed by larsen 2002 from 40 years of sounding rocket chemical release experiments

a 400 year record of environmental change in an euxinic fjord as revealed by the sedimentary biomarker record a 400 year sedimentary record of the euxinic kyllaren fjord was investigated using organic biogeochemical geochemical and sedimentological approaches accumulation rates of a suite of biomarkers and in some cases their stable carbon isotopic composition were determined biomarkers were separated into three different groups terrestrial derived general aquatic marine derived and aquatic marine derived but related to high primary productivity variations in bulk sediment parameters and biomarker accumulation rates with depth were used to interpret the sedimentary record we infer that in the first half of the 19th century an environmental change occurred caused by a change in either the precipitation regime vegetation and or land use the data also show that in the last century and especially in the last decades a distinct increase in primary productivity occurred most likely this is caused by a natural eutrophication due to the transformation of the fjord from an open to a confined system by the building of a partially open dam in 1954 possibly combined with anthropogenic eutrophication a concurrent shoaling of the fjord chemocline may have had a mediating effect in the change towards a higher productivity by enhancing nutrient and carbon recycling enhanced carbon recycling is reflected by decreased 13c values of several biomarkers

glacial and tectonic control on fjord morphology and sediment deposition in the magellan region 53 s chile in the patagonian andes erosion by temperate pleistocene glaciers has produced a deeply incised fjord system in which glacial and non glacial sedimentswere deposited since the late glacial glacier retreat so far fjord bathymetry and structures in the sediment infill were widely unexplored here we report the results of an investigation of morphology and sediment characteristics of a 250 km long fjord transect across the southernmost andes 53 s using multibeam and parametric echosounder data and sediment cores subaquatic morphology reveals continuity of on land tectonic lineaments mapped using field and remote sensing data our results indicate that glacial erosion and fjord orientation are strongly controlled by three major strike slip fault zones furthermore erosion is partly controlled by older and or reactivated fracture zones as well as by differential resistance of the basement units to denudation basement morphology is regionally superimposed by late glacial and holocene subaquatic moraines which are associated to known glacier advances the moraines preferentially occur on basement highs which constrained the glacier flows this suggests that the extent of glacier advances was also controlled by basement morphology subaquatic mass flows fluid vent sites as well as distinct late glacial and holocene sediment infills have furthermore modified fjord bathymetry in the western fjord system close to the strait of magellan subaquatic terraces occur in 20 to 30 m water depth providing an important tag for proglacial lake level during the late glacial

sensitivity of mesospheric mean flow planetary waves and tides to strength of gravity wave drag a global circulation model which extends from the surface to 125 km is used to study how the strength of gravity wave drag affects the dynamics of the mesosphere the strength of gravity wave drag has a strong influence on the zonal mean state of the mesosphere in particular the magnitude and variability of the summer mesopause temperature and the shear on the top of the mesospheric jets this change in the zonal mean state strongly affects the susceptibility of the mesosphere to baroclinic and or barotropic instability and hence the formation of the 2 day wave the 2 day wave in turn interacts nonlinearly with the diurnal tide producing secondary waves and a reduction in amplitude of the diurnal tide previous studies with quasi linear mechanistic tidal models have captured some semiannual variation in tidal amplitude through direct interactions between tides and gravity waves our fully nonlinear global circulation model results support an alternative explanation in terms of interactions between planetary waves and tides

foraminiferal reconstruction of mid to late holocene ocean circulation and climate variability in disko bugt west greenland benthic foraminifera from two cores collected from disko bugt a large marine embayment in west greenland are used to investigate hydrographic changes during the mid to late holocene the records document fluctuations in the west greenland current wgc linked to large scale changes in north atlantic circulation and for one core impacts of local climate changes in particular changes in the cold east greenland current egc and the warm more saline irminger current ic influence the wgc and propagate into disko bugt the cores record subsurface warming associated with the holocene thermal maximum htm from c 6 to 5 ka cal bp gradual cooling of wgc from 5 ka cal bp was interrupted by an abrupt warm interval from 3 9 to 3 5 ka cal bp before cooling became more prominent from 3 5 to 2 ka cal bp this cold period corresponds to the well documented northern hemisphere cooling of the neoglacial and we interpret it as reflecting enhanced flux from the egc and reduced ic flux to the wgc in disko b

late weichselian and holocene sedimentary environments and ice rafting in isfjorden spitsbergen abstract multi proxy analyses of two sediment cores from central isfjorden were used to reconstruct the glacial history in central spitsbergen during the late weichselian and the holocene and to relate iceberg rafting and sea ice rafting to climatic and oceanographic changes in the north atlantic region a basal till was deposited beneath an ice stream prior to 12 700 cal years bp calendar years before the present several tidewater glaciers influenced the sedimentary environment during the younger dryas and probably already during the allerod the younger dryas cooling might be reflected by enhanced sea ice formation and suspension settling as well as reduced iceberg rafting the final deglaciation was dominated by intense iceberg rafting it terminated around 11 200 cal years bp optimum holocene climatic and oceanographic conditions with significantly reduced ice rafting occurred between c 11 200 and 9000 cal years bp ice rafting occurred almost exclusively from icebergs after 10 200 cal years bp the icebergs most probably originated from tidewater glaciers on east spitsbergen indicating the presence of a strong east west temperature gradient at this time an increase of iceberg rafting around 9000 cal years bp followed by enhanced sea ice rafting reflects the onset of a general cooling in the western barents sea svalbard region comparatively intense rafting from icebergs and sea ice between 9000 and 4000 cal years bp is related to this cooling a general reduction in ice rafting after 4000 cal years bp is most probably the result of the enhanced formation of shore fast and or more permanent sea ice cover reducing the drift of icebergs and sea ice in the fjord the results indicate that the palaeoenvironmental conditions on central spitsbergen to a large degree depended on the oceanographic conditions in the western barents sea and west off spitsbergen however climatic trends affecting greenland and the entire north atlantic region can also be identified

depositional settings and evolution of a fjord system during the carboniferous glaciation in northwest argentina abstract fjord systems represented by glacial diamictites and postglacial transgressive shales formed in the basins of western argentina during the late carboniferous gondwana glaciation well exposed fjord deposits of the guandacol formation were studied in the loma de los piojos region protoprecordillera where they fill a 2 9 km wide paleovalley with steep side walls and a relatively flat floor the valley cross cuts lower devonian sandstones and mississippian mudstones and sandstones and provides evidence of glacial abrasion including striated pavements and glacial microtopography grooves ridges and striae based on the analysis of seven sedimentary logs eight sedimentary facies in the valley fill were recognized a massive diamictites b laminated mudstones with dropstones c stratified diamictites d clast supported conglomerates and sandstones e deformed diamictites conglomerates and sandstones f folded diamictites g mudstones interbedded with sandstones and h stacked and amalgamated sandstones these sedimentary facies are grouped into two principal facies assemblages that represent different stages of the paleovalley fill assemblage 1 is composed of diamictites facies a c and f laminated mudstones with dropstones facies b and conglomerates facies d and e which represent glacially influenced sedimentation in the paleovalley assemblage 2 represents the paleovalley fill when glacial influence ceased and comprises laminated mudstones interbedded with sandstones facies g and stacked sandstone beds facies h that mostly record deltaic sedimentation stratigraphic relationships plant fossils found in the paleovalley walls and palynological assemblages recovered in mudstones of facies d help to establish an early pennsylvanian age for both the incision and the filling of the paleovalley the studied paleovalley records an exceptional example of the western gondwanan glacial to postglacial transition due to the continuous stratigraphic succession within the paleovalley as well as palynological megafloristic and radiometric data this example provides a complete framework of the late carboniferous postglacial evolution in western gondwana

holocene glacier and climate variations in vestfirðir iceland from the modeling of drangajokull ice cap abstract drangajokull is a maritime ice cap located in northwest vestfir ir iceland drangajokull s evolution is therefore closely linked to atmospheric and ocean variability in order to better constrain the holocene climate and glacier history of vestfir ir we model the past evolution of drangajokull ice cap simulations from 10 ka to present are forced by general circulation model output ice core based temperature reconstructions and sea surface temperature reconstructions based on these 10 thousand year simulations drangajokull did not persist through the holocene we estimate that air temperatures were 2 5 3 0 c higher during the holocene thermal maximum than the local 1960 1990 average simulations support drangajokull s late holocene inception between 2 and 1 ka though intermittent ice likely occupied cirques as early as 2 6 ka drangajokull is primarily a little ice age ice cap it expanded between 1300 and 1750 ce with the most rapid growth occurring between 1600 and 1750 ce the maximum holocene extent of drangajokull occurred between 1700 and 1925 ce despite the lowest late holocene temperatures occurring between 1650 and 1720 ce between 1700 and 1925 ce temperatures were likely 0 6 0 8 c lower than the 1950 2015 reference temperature the modern equilibrium line altitude ela is bracketed by topographic thresholds a 1 c temperature increase from the modern ela would eliminate the ice cap s accumulation area while a reduction of 0 5 c would lead to the rapid expansion of the ice cap across vestfir ir the proximity of drangajokull to topographic thresholds may explain its late inception and rapid expansion during the little ice age

benthic stable isotope variability in the trondheimsfjord during the last 50 years proxy records of mixing dynamics related to nao abstract benthic stable isotopes 18 o c and 13 c c in the trondheimsfjord reliably reflect the prevailing hydrological conditions with regard to the distance to the fjord entrance and the local topography at the fjord entrance the 18 o c and 13 c c variabilities record changes in the temperature of the north atlantic current nac and in the delivery of terrigenous organic matter by the norwegian coastal current ncc and the fjord estuarine circulation respectively in the inner fjord basins the benthic stable isotope compositions are predominantly controlled by hydrological characteristics linked to internal mixing and the prevailing wind pattern the fjord deep basins are relatively sheltered from erosion and both land and marine derived sediments accumulate at very high rates indicating past regional climate and associated driving parameters in the present study we discuss the recent variability last 55 years of the stable isotope compositions oxygen and carbon measured in calcite shells of the benthic foraminiferan melonis barleeanus with regard to the changing influence of marine versus fresh water inputs and of the prevailing wind patterns the relative influence of marine versus continental waters were analysed as well as the complex topography and the related hydrology of the trondheimsfjord using sediment cores collected in three different settings along the fjord axis the variability the of stable isotope compositions obtained from the sedimentary archives is compared with in situ instrumental measurements over the investigated time interval

stable oxygen and carbon isotope information on the establishment of a new opportunistic foraminiferal fauna in a swedish skagerrak fjord basin in 1979 1980 significant faunal changes reported fromrecent coastal environments which are not directly influenced by urban and industrial impact are rarely seen in gullmar fjord on the swedish west coast a significant foraminiferal fauna change occurred in connectionwith severe low oxygen conditions that evolved in thewinter of 1979 1980 a foraminiferal fauna marked by common skagerrak kattegat species which had previously characterised the deep fjord basin was replaced by the opportunistic low oxygen tolerant species stainforthia fusiformis williamsson to study this phenomenon further we performed stable oxygen and carbon isotope analyses on the indicator species itself s fusiformis both on specimens from sediment cores representing approximately the last 85 years and on living stained individuals taken from a transect across the deep fjord basin our purpose was to detail how and why s fusiformis came to dominate the fauna the oxygen isotope results suggest that salinities and temperatures in the deep basin have been relatively constant over the last c 85 years while the carbon isotopes show a significant change towards more negative values in association with the faunal shift of 1979 1980 the combined results from both the cores and the surface sediments suggest that s fusiformis did not inhabit the deep basin until 1980 before then almost all specimens of s fusiformis were small sized and their carbon isotope values suggest they were re deposited shallow water specimens that had been transported down to the central deep basin as part of a suspension load after a major faunal extinction in 1979 1980 s fusiformis of all sizes suddenly appeared in large numbers and their carbon isotopic values were similar to the signal from registered in the recent living fauna within the deep basin this suggests that the opportunistic s fusiformis established itself in the deep basin as a consequence of the severe low oxygen event and the faunal crash of the previously dominating skagerrak kattegat fauna less

a continuous marine record 8000 1600 cal yr bp from the malangenfjord north norway foraminiferal and isotopic evidence holocene oceanography and climate were studied in the continuous marine sediment sequence in a piston core from the high latitude malangenfjord north norway using benthic foraminifera and stable isotopes radiocarbon dates indicate that the investigated sequence covers the period from c 8000 to 1600 cal bp and has a sedimentation rate of 0 3 12 7 m 1000 years bottom water temperatures reconstructed from benthic foraminiferal stable isotopes in the malangenfjord show a cooling of c 3 c ranging from 10 c and reaching c 7 c at 1600 cal yr bp which is similar to present bottom water temperature at the core location a planktic foraminiferal 18o record was established from c 6400 to 1600 cal yr bp generally following the same pattem as the benthic record this long term cooling correlates to the decreasing insolation at 70 n following the orbital forcing the long term cooling also corresponds well with atmospheric proxy records implying a close ocean atmosphere coupling it is also indicated both b

late holocene atlantic bottom water variability in igaliku fjord south greenland reconstructed from foraminifera faunas a high resolution record of late holocene subsurface water mass characteristics in outer igaliku fjord south greenland is presented based on benthic foraminifera faunas from core po 243 451 collected from a water depth of 304 m strati cation with atlantic water masses present in the lower part of the water column is suggested to have prevailed during the last 3200 cal years except for a period referred to as the mediaeval warm period mwp during the mwp c ad 885 1235 the outer part of igaliku fjord experienced enhanced vertical mixing and a high hydrodynamic energy level which we ascribe to increasing wind stress through this period corresponding to the period of the norse settlement the transition from the mwp to the little ice age lia shows a two step pattern with a short climatic amelioration around ad 1520 before maximum cooling occurred the intensified wind stress and the overall environmental change are suggested to have contributed to the loss of the norse settlement in greenland periods with strong stratification and marked in uence of atlantic subsurface water masses around 2 6 1 3 ka bp and during the lia are correlated to north atlantic holocene ice rafting events reported by bond et al 1997

observed temperature two day wave and its relatives near the stratopause the two day wave is observed in the upper atmosphere research satellitemicrowave limb sounder temperature data around 40 58 km between december 1991 and september 1994 the two day wave temperature signature is most significant after each solstice when the derived easterly winds near the stratopause extend across the equator to at least 208 latitude in the winter hemisphere and the zonal mean winds near the equator are inertially unstable with observed inertial instability disturbances the observed two day wave consists of a 2 0 day period zonal wavenumber 3 and a 1 8 day period zonal wavenumber 4 component named 3 2 0 and 4 1 8 respectively the 3 2 0 component is dominant during two of the three available austral summers but its amplitude is much weaker than the 4 1 8 component during the two observed boreal summers during the austral summers correspondence between amplification of the two day wave temperature signatures regions of reversed potential vorticity gradient due to meridional curvature of the zonal mean flow and the critical lines for the 3 2 0 and 4 1 8 modes suggest barotropic instability as a source of both wave components momentum redistribution by observed inertial instability appears to barotropically destabilize the equatorward flank of the easterly jet where the wave components subsequently grow during the boreal summers the 4 1 8 component appears to be excited by instability that is associated with vertical shear and curvature of the flow seated above the observational domain the boreal 3 2 0 mode appears unrelated to the zonal flow instability within the observational domain and may reflect a normal mode like response during these periods

fjord insertion into continental margins driven by topographic steering of ice fjords line mountainous continental margins where icesheets and glaciers once stood a two dimensional model simulation suggests that fjords can be eroded within one million years primarily in response to topographic ice steering and erosion from ice discharge subsequent glaciers that form on these landscapes are smaller and exhibit greater responses to climate change

fjord stratigraphy and processes evidence from the ne atlantic fensfjorden system fjords commonly hold sediment basins with high temporal resolution that mirror land and marine based processes and depositional environments during a glacial interglacial cycle here we present topas seismic profiles with a vertical resolution of 30 cm bathymetric records and a gravity core from fensfjorden west norway which allow a detailed study of sedimentary processes and depositional environments in a ne atlantic fjord system fensfjorden hosts a sediment volume of 0 70 km3 and the sediment basins evolved reach a maximum thickness of 100 m the basins are characterized by a lower acoustically well laminated glacimarine unit of allerod and younger dryas age this unit is overlain by several acoustically transparent lenses interpreted to be slide debrites we suggest these slide debrites to be a result of recurrent mass failures that occurred between 11 500 and 2100 cal a bp a thin late holocene hemipelagic unit drapes the slide debrites during the late holocene the sedimentation rates in fensfjorden decreased from 0 110 to 0 040 cm a 1 and two turbidity currents occurred in the 2040 1190 cal a bp time period this ability to map fjord processes in more detail has furthermore made it possible to revise the established stratigraphical framework for ne atlantic fjords copyright 2013 john wiley sons ltd

intraseasonal and interannual variability of the quasi 2 day wave in the northern hemisphere summer mesosphere this study uses global synoptic meteorological fields from a high altitude data assimilation system to investigate the quasi 2 day wave q2dw and migrating diurnal tide during the northern hemisphere nh summers of 2007 2009 by applying a two dimensional fast fourier transform to meridional wind and temperature fields we identify q2dw source regions and diagnose propagation of q2dw activity into the upper mesosphere and lower thermosphere we find that the q2dw in nh summer is composed primarily of westward propagating zonal wave number 3 and wave number 4 components that originate within baroclinically unstable regions along the equatorward flank of the summer midlatitude easterly jet the amplitude of the wave number 3 q2dw tends to peak in july while the amplitude of the wave number 4 q2dw tends to peak in late june and again in early august the seasonal mean q2dw amplitudes are largest in 2009 when the amplitude of the migrating diurnal tide in the upper mesosphere near 30 n was relatively weak however there is no evidence of rapid amplification of the q2dw via nonlinear interaction with the diurnal tide instead variations of q2dw amplitudes during nh summer appear to be linked to variations in the strength and location of the mesospheric easterly jet from one summer to the next with a stronger jet producing larger q2dw amplitudes linear instability model calculations based on the assimilated wind fields indicate that the fastest growing modes are zonal wave numbers 3 and 4 with periods near 2 days that originate in the vicinity of the easterly jet

coordinated investigation of summer time mid latitude descending e layer es perturbations using na lidar ionosonde and meteor wind radar observations over logan utah 41 7 n 111 8 w 1 it is well known that there is a strong correlation between the formation of a descending sporadic e layer es and the occurrence of large upper atmospheric zonal wind shears most likely driven by solar thermal tides and or gravity waves we present new results of es perturbation events captured between 13 and 17 july 2011 ut days 194 198 as part of a coordinated campaign using a wind temperature na lidar at utah state university 41 7on 111 8 w and a canadian advanced digital ionosonde cadi scientific instrumentation ltd saskatoon saskatchewan canada and skiymet meteor wind radar both located at nearby bear lake observatory 41 9 n 111 4 w during this period the cadi detected strong descending es on 2 days 195 and 197 when large modulations of the top side mesospheric na layer occurred in synchronism with strong oscillations in the ionosonde e region echoes a weakening in the descending e layer echoes was observed on the other 2 days 196 and 198 coincident with a large reduction in the zonal diurnal and semidiurnal amplitudes above 95 km both tidal components were found to have comparable contributions to the total zonal wind shear that was critical for es formation and its downward propagation further investigation indicates that the weakening tidal amplitudes and the occurrence of the es events were also influenced by a strong quasi two day period modulation suggesting significant quasi two day wave qtdw interactions with the tides indeed a nonlinear wave wave interaction induced 16 hour period child wave was also detected with amplitude comparable to that of the prevailing tides these interaction processes and their associated effects are consistent with earlier thermosphere ionosphere mesosphere electrodynamics general circulation model studies of nonlinear interactions between the migrating tidal waves and the qtdw and were probably responsible for the observed damping of the tidal amplitudes resulting in the disruption of the es

late holocene paleoceanographic evidence of the influence of the aleutian low and north pacific high on circulation in the seymour belize inlet complex british columbia canada foraminiferal and thecamoebian faunas from the seymour belize inlet complex sbic a fjord network situated on the mainland coast of british columbia were studied to assess climatic cycles and trends impacting the area through the ad 850 ad 2002 interval ocean circulation patterns prevalent in the sbic are strongly linked to precipitation which is closely linked to the relative strength and position center of action coa of the seasonally developed aleutian low al and north pacific high nph atmospheric circulation gyres through interpretation of cluster analysis and ordination methods a period of weak estuarine circulation was recognized to have impacted the sbic area between ad 850 and ad 1500 during this time waters in the sbic were dysoxic to anoxic and the sediment water interface was comprised of a depauperate foraminiferal fauna consisting of low diversity agglutinated forms these reduced oxygen conditions came about as a result of diminished precipitation in the sbic catchment as the coa of the al progressively migrated westward over time resulting in greatly reduced estuarine circulation and only infrequent and feeble incursions of well oxygenated open ocean water into the sbic basin by ad 1575 following a gradual transition period of 75 years when circulation patterns in the inlet were unstable very strong estuarine circulation developed in the sbic concomitant with the onset of the little ice age lia in western canada in the sbic this interval was characterized by higher levels of precipitation which greatly enhanced estuarine circulation resulting in frequent incursions of cold well oxygenated ocean currents into the bottom waters of the sbic and the development of a diverse calcareous foraminiferal fauna this circulation pattern began to break down in the late 19th century ad and by ad 1940 conditions similar to those that existed in the inlet prior to ad 1500 had redeveloped a process that continues at present

role of the gulf stream and kuroshio oyashio systems in large scale atmosphere ocean interaction a review abstract ocean atmosphere interaction over the northern hemisphere western boundary current wbc regions i e the gulf stream kuroshio oyashio and their extensions is reviewed with an emphasis on their role in basin scale climate variability sst anomalies exhibit considerable variance on interannual to decadal time scales in these regions low frequency sst variability is primarily driven by basin scale wind stress curl variability via the oceanic rossby wave adjustment of the gyre scale circulation that modulates the latitude and strength of the wbc related oceanic fronts rectification of the variability by mesoscale eddies reemergence of the anomalies from the preceding winter and tropical remote forcing also play important roles in driving and maintaining the low frequency variability in these regions in the gulf stream region interaction with the deep western boundary current also likely influences the low frequency variability surface heat fluxes damp the low frequency sst anomalies ove

the holocene record of loch etive western scotland influence of catchment and relative sea level changes abstract two sediment cores from inner loch etive a deep fjord basin on the west coast of scotland reveal a continuous sediment sequence spanning the last 10 000 yr benthic foraminiferal assemblages indicate that marine conditions prevailed in loch etive throughout the holocene however changes in sediment grain size composition and magnetic susceptibility suggest that the strength and frequency of deep water renewal events has varied through time this exchange with coastal water is controlled mainly by relative sea level changes influencing sill depth and the influx of freshwater to the loch the very early holocene sediments are well sorted coarse silt fine sands with a diverse assemblage of calcareous foraminifera indicating frequent renewal of bottom waters during this period immediately following the withdrawal of younger dryas glaciers denudation rates were high in the catchment area the period 9 7 ky bp during which relative sea level rose in this part of w scotland is characterised by highly variable environments the grain size data indicate an enhanced transport of sandy bed load material from the bonawe sill region to the basin deep during the mid holocene relative sea level high 8 9 m higher than present high relative sea levels at this time would explain the occurrence of frequent vigorous deep water renewal events and an increased tidal current regime in the loch the late holocene record is characterised by an upward fining of sediment grain size disappearance of calcareous benthic foraminifera and increasing organic content suggesting a development towards a more restricted fjordic circulation in response to the progressive lowering of relative sea level a sudden acceleration in this late holocene trend took place during the last millennium during which time human land use and deforestation have influenced the sediment and organic material flux to loch etive it appears that average holocene sediment accumulation rates in the bonawe deep were about 0 01 0 03 g cm 2 yr 1 which is far below modern estimates for the site this can be explained by vigorous bottom current activity during much of the holocene leading to a low net depositional rate

why sedimentologists are interested in fjords abstract fjords offer a unique environmental setting to study geochemical and sedimentological processes and the interaction between these processes and biological systems they can be described generally as enclosed mini oceans where the rate of processes is fast and associated environmental gradients are large most fjords are easily accessible and the resources necessary to study them are relatively modest compared to those required for sedimentological work in the open ocean fjords differ significantly with respect to sediment input transport and depositional environment those situated in glaciated areas receive sediment laden meltwater that promotes high deposition rates that are often evident as deltaic deposits in these instances the bottom sediments are characteristically inorganic and show large variations in grain size in contrast fjords with low sediment input high organic production and insufficient deep water renewal may be anoxic either seasonally or permanently these highly organic environments tend to accumulate sedimentary facies that are especially applicable to geochemical process studies or to high resolution paleoclimatic investigations that are dependent on minimal post depositional sediment mixing e g bioturbation

benthic foraminiferal distributions in chilean fjords 47 s to 54 s abstract surface sediment samples collected from the fjord region of southern chile 47 to 54 south were analyzed for benthic foraminifera a total of 175 species were identified including agglutinated and calcareous benthic taxa hierarchical cluster analysis of the foraminiferal data resulted in the recognition of three distinct biofacies inner fjord intermediate fjord and channel and oceanic biofacies geographically controlled by relative position between the pacific ocean and fjord heads similarity percentage simper analysis identified key taxa in the definition of the biofacies that include globocassidulina rossensis cassidulina laevigata and bulimina notovata principal components analysis resulted in two principal components representing sediment size and bottom water temperature and salinity regional distributions are strongly controlled by the oceanographic conditions influenced from the pacific in the west and the glacial freshwater input from the east localized distributions of foraminifera are controlled by conditions influenced by the physiography of the individual fjords and channels the distribution of chilean fjord foraminifera and their environmental associations are consistent with results from other temperate to high latitude fjord foraminiferal studies

western boundary currents and frontal air sea interaction gulf stream and kuroshio extension abstract in the northern hemisphere midlatitude western boundary current wbc systems there is a complex interaction between dynamics and thermodynamics and between atmosphere and ocean their potential contribution to the climate system motivated major parallel field programs in both the north pacific kuroshio extension system study kess and the north atlantic climate variability and predictability clivar mode water dynamics experiment climode and preliminary observations and analyses from these programs highlight that complexity the gulf stream gs in the north atlantic and the kuroshio extension ke in the north pacific have broad similarities as subtropical gyre wbcs but they also have significant differences which affect the regional air sea exchange processes and their larger scale interactions the 15 yr satellite altimeter data record which provides a rich source of information is combined here with the longer historical record from in situ data to describe and compare the curr

the origin of modern agglutinated foraminiferal assemblages evidence from a stratified fjord loch etive a silled 145 m deep fjord on the scottish west coast provides an example of modern benthic foraminiferal assemblages at intermediate depths i e below the intertidal zone and above the ccd consisting almost exclusively of organic cemented agglutinated forms since such faunas from intermediate depths are rare in modern oceans but relatively common in the fossil record the present study allows new insights into one kind of ancient environment for which there are few modern analogues the strong dominance of agglutinated forms both living and in some dead assemblages of foraminifera to the exclusion of calcareous taxa is attributed to the unusual oceanographic conditions these include a combination of restricted deep water renewals and strong influence of freshwater which drains through large areas relative to the size of the loch of vegetated land the result is calm bottom water conditions with commonly occurring oxygen depletion although not anoxic brackish water throughout the water column salinity 28 in the deeper parts and organic rich mostly terrestrially derived sediments with geochemical properties which to a much larger degree than open marine ones are controlled by local input this environment supports low abundance and low diversity live assemblages mainly restricted to the surface 1 cm of sediment the dead assemblages show similar faunal characteristics but the calcareous components are due to carbonate dissolution even more reduced one of the calcareous species in loch etive is elphidium albiumbilicatum its occurrence is the first record in british waters and it matches the previously suggested southern limit of its distribution analysis of a 90 cm long core representing sediments deposited over the past two centuries shows the presence of a calcareous dominated assemblage including more marine species with a higher diversity in the lower part this suggests that loch etive is in the process of going from a marine to a more terrestrial dominated environment the relatively high sedimentation rate 0 5 cm per yr the apparent lack of smearing through bioturbation and the presence of faunal changes in response to reduced marine influence over the past centuries shows that loch etive has a good potential for performing high resolution climatic studies

the character of polar tidal signatures in the extended canadian middle atmosphere model the characteristics of the diurnal semidiurnal and terdiurnal tides zonal wave numbers 5 to 5 in temperature and zonal wind in the polar mesosphere and lower thermosphere region as simulated by the extended canadian middle atmosphere model are examined the most significant diurnal semidiurnal and terdiurnal tides in the polar regions are ds0 dw1 and de1 sw3 sw2 sw1 ss0 se1 and se2 and tw3 ts0 and tw1 respectively and their latitudinal structures seasonal variations and hemispheric asymmetries noted of these components ds0 tw1 ts0 and tw3 exhibit a seasonally symmetric variation with both hemispheres strengthening simultaneously on the other hand dw1 strengthens asymmetrically so that when one hemisphere is strong the other is weak the remainder show no seasonal tendency but vacillate on shorter than seasonal time scales in a symmetric or antisymmetric manner at different times of the year global scale correlations of the amplitudes of the migrating tides dw1 sw2 and the stationary planetary wave 1 and the assumed child nonmigrating tides are also examined the results indicate that the correlations are highly time scale dependent and the significant correlations seen with the original time series are mainly due to longer term variations 18 days there are no consistent global correlations associated with the short term variations 18 days among these waves

large scale waves in the mesosphere and lower thermosphere observed by saber observations made by the sounding of the atmosphere using broadband emission radiometry saber instrument on board nasa s thermosphere ionosphere mesosphere energetics and dynamics timed satellite have been processed using salby s fast fourier synoptic mapping ffsm algorithm the mapped data provide a first synoptic look at the mean structure and traveling waves of the mesosphere and lower thermosphere mlt since the launch of the timed satellite in december 2001 the results show the presence of various wave modes in the mlt which reach largest amplitude above the mesopause and include kelvin and rossby gravity waves eastward propagating diurnal oscillations non sunsynchronous tides and a set of quasi normal modes associated with the so called 2 day wave the latter exhibits marked seasonal variability attaining large amplitudes during the solstices and all but disappearing at the equinoxes saber data also show a strong quasi stationary rossby wave signal throughout the middle atmosphere of the winter hemisphere the signal extends into the tropics and even into the summer hemisphere in the mlt suggesting ducting by westerly background zonal winds at certain times of the year the 5 day rossby normal mode and the 4 day wave associated with instability of the polar night jet are also prominent in saber data

observations of the quasi two day wave in the middle and lower atmosphere over christmas island we present analyses of data collected at christmas island in the mesosphere and lower thermosphere using a meteor echo detection and collection system medac in addition to data collected in the troposphere and lower stratosphere using a clear air stratosphere troposphere st radar these data which provide 5 years of semicontinuous horizontal wind velocity estimates are analyzed to determine the temporal structure of the quasi two day wave in the middle and lower atmosphere our results show the presence of strong wave activity in the middle atmosphere during late january and early february as well as a secondary maxima in june august for each of the years we have data however the magnitude and duration of the wave events observed in late january and early february exhibit interannual variability

a 275 year ice core record from akademii nauk ice cap severnaya zemlya russian arctic between 1999 and 2001 a 724 m long ice core was drilled on akademii nauk the largest glacier on severnaya zemlya russian arctic the drilling site is located near the summit the core is characterized by high melt layer content the melt layers are caused by melting and even by rain during the summer we present high resolution data of density electrical conductivity dielectrical profiling stable water isotopes and melt layer content for the upper 136 m 120 m w e of the ice core the dating by isotopic cycles and electrical conductivity peak identification suggests that this core section covers approximately the past 275 years singularities of volcanogenic and anthropogenic origin provide well defined additional time markers long term temperatures inferred from 12 year running mean averages of d 18 o reach their lowest level in the entire record around 1790 thereafter the d 18 o values indicate a continuously increasing mean temperature on the akademii nauk ice cap until 1935 interrupted only by minor cooling episodes the 20th century is found to be the warmest period in this record

observations of the 2 day wave in nmc stratospheric analyses abstract observational characteristics of the 2 day wave a westward propagating zonal wave 3 oscillation in the summer subtropical upper stratosphere and mesosphere are studied based on five years of national meteorological center nmc operational stratospheric analyses these data show episodic occurrence of the 2 day wave in the upper stratosphere in january centered near 20 s and july august centered near 20 n these episodes are strongly correlated with observed reversals of the zonal mean potential vorticity gradient near the core of the summer easterly jet consistent with previous suggestions that the 2 day wave is generated by an in situ instability of this jet on the other hand the horizontal and vertical structure of the waves is very similar to that calculated by salby for a global normal mode rossby wave the combination of normal mode structure and instability signature suggests that the 2 day wave is a near resonant mode forced by dynamical instability

glacial to postglacial submarine landform assemblages in fiords of northeastern baffin island abstract fiord morphology plays a fundamental role in glacier flow dynamics and on ice margin stability as most of the present day margins of the greenland ice sheet lays in fiords there is a need for understanding short and long term glacial dynamics in fiord settings we investigate ice sheet retreat patterns in previously glaciated submarine terrain of northeastern baffin island fiords to provide analogues for modern and future ice sheet response to climate change and sea level rise geomorphological maps constructed from the interpretation of swath bathymetry imagery in fiords of northeastern baffin island reveal a wide range of glacial to postglacial landforms that allow the reconstruction of past ice sheet retreat dynamics ice flow landforms such as mega scale glacial lineations crag and tails and meltwater channels reveal the direction and behaviour of late foxe ice flow through the fiords the presence of undisturbed elongated landforms within the fiords suggests that ice streams have probably been active until the late stage of deglaciation landforms transverse to ice flow direction include grounding zone wedges frontal moraines grounding line fans recessional moraines and de geer moraines these landforms are interpreted as the result of former standstills of the ice margin during deglaciation the occurrence of grounding zones in deep 800 m part of the fiords contrasts with studies suggesting instability and rapid retreat of outlet glaciers over deep fiord basins sediment filled basins often characterised by the presence of turbidity channels gullies and mass movement scars occur in between the moraines sediment filled basins with a ponded architecture between sills illustrate that most of the sediment accumulation was ice proximal during deglaciation and characterised by gravity driven flows the proposed landform assemblage model for northeastern baffin fiords includes landforms typical of different fiord landsystems

an eastward propagating two day wave evidence for nonlinear planetary wave and tidal coupling in the mesosphere and lower thermosphere 1 temperature observations from the saber instrument on the timed spacecraft are used to investigate the structure and evolution of an eastward propagating zonal wavenumber 2 disturbance with a period near two days this oscillation obtains a maximum amplitude of nearly 10 k in the southern hemisphere mid latitudes during late january the timing and location of this planetary wave is coincident with the regular quasi two day wave intensification that occurs annually in late january the period wavenumber and spatial structure of the eastward propagating two day wave are consistent with a wave that results from a nonlinear interaction between the quasi two day wave and the migrating diurnal tide the existence of an eastward propagating wave with a period near two days coincident with the westward propagating two day wave will have an impact on the interpretation of ground based observations analysis of the saber temperature observations are utilized to determine the structure and evolution of both this eastward propagating two day wave and the classic westward propagating zonal wavenumber 3 quasi two day wave during january 2005

short term variability in the migrating diurnal tide caused by interactions with the quasi 2 day wave 1 the migrating diurnal tide is one of the dominant dynamical features in the low latitudes of the earth s mesosphere and lower thermosphere mlt region representing the atmospheric response to the largest component of solar forcing ground based observations of the tide have resolved short term variations attributed to nonlinear interactions between the tide and planetary waves that are also in the region using the ncar thermosphere ionosphere mesosphere electrodynamics general circulation model time gcm we simulate a quasi 2 day wave qtdw event under late january conditions in this case sideband sum and difference child waves are resolved indicating that a nonlinear interaction is occurring between the qtdw and the tide the migrating diurnal tide in the mlt displays local amplitude decreases of 20 40 as well as a shortening of vertical wavelength by roughly 4 km examining the physical mechanisms driving the interaction nonlinear advection is found to result in amplification of the tide in some regions and damping in others manifesting as increased smoothing of the tidal structure when the qtdw is present in the mlt additionally the qtdw also enhances the easterly summer mean wind jet that can also account for changes in tidal amplitude and vertical wavelength we find that qtdw induced background atmosphere changes in time gcm can drive tidal variability at levels greater than nonlinear advection a possibility not previously considered

a tree ring based reconstruction of the atlantic multidecadal oscillation since 1567 a d 1 we present a tree ring based reconstruction of the atlantic multidecadal oscillation amo which demonstrates that strong low frequency 60 100 yr variability in basin wide 0 70 n sea surface temperatures ssts has been a consistent feature of north atlantic climate for the past five centuries intervention analysis of reconstructed amo indicates that 20th century modes were similar to those in the preceding 350 yr and wavelet spectra show robust multidecadal oscillations throughout the reconstruction though the exact relationships between low frequency sst modes higher frequency 7 25 yr atmospheric modes e g north atlantic oscillation arctic oscillation and terrestrial climates must still be resolved our results confirm that the amo should be considered in assessments of past and future northern hemisphere climates

two ice core δ18o records from svalbard illustrating climate and sea ice variability over the last 400 years ice cores from the relatively low lying ice caps in svalbard have not been widely exploited in climatic studies owing to uncertainties about the effect of meltwater percolation however results from two new svalbard ice cores at lomonosovfonna and austfonna have shown that with careful site selection high resolution sampling and multiple chemical analyses it is possible to recover ice cores from which part of the annual signals are preserved despite the considerable meltwater percolation the new svalbard ice cores are positioned in different parts of svalbard and cover the past 800 years in this paper we focus on the last 400 years the 6180 signals from the cores are qualitatively similar over most of the twentieth century suggesting that they record the same atmospheric signal prior to ad 1920 the austfonna ice core exhibits more negative 6180 values than lomonosovfonna although there are intermittent decadal scale periods throughout the record with similar values we suggest that the differences reflect the effect of the inversion layer during the winter the pattern in the 6180 records is similar to the longyearbyen airtemperature record but on an annual level the correlation is low the austfonna record correlates well with the temperature record from the more distant and southwesterly located jan mayen a comparison of the ice core and sea ice records from this period suggests that sea ice extent and austfonna 6180 are related over the past 400 years this may reflect the position of the storm tracks and their direct influence on the relatively low altitude austfonna lomonosovfonna may be less sensitive to such changes and primarily record free atmospheric changes instead of variations in sea ice extent the latter is probably a result of its higher elevation

holocene mass transport activity and climate in outer isfjorden spitsbergen marine and subsurface evidence the analyses of high resolution seismic data swath bathymetry data and sediment cores from the basin svensksunddjupet in isfjorden spitsbergen reveal the deposits of repeated slope failures most of the slope failures occurred during three periods at c 9650 cal bp 8350 8200 cal bp and 3000 cal bp suggested factors causing instability of the slopes include earthquake activity resulting from rapid isostatic uplift excess pore pressure caused by relative sea level fall and or the presence of gas as well as climatic changes mass transport deposits at the mouth of an incision at the southern slope of svensksunddjupet are suggested to mainly relate to runoff from the land based glacier vardebreen the increase of the mass transport activity may indicate that vardebreen either formed or increased in size at c 7000 cal bp

the 8200 cal yr bp event reflected in the arctic fjord van mijenfjorden svalbard detailed stratigraphic investigations of a high resolution sediment core from the arctic fjord van mijenfjorden svalbard reveal significant reductions in benthic foraminiferal 18o of 0 4 and 0 2 0 3 dated to c 8200 and 8450 cal yr bp respectively these reductions combined with changes in the benthic foraminiferal fauna and ird indicate substantial changes in the hydrography of the fjord such as freshening of the bottom water enhanced sea ice distribution and reduced biogenic production the age and duration 100 years of the youngest event is directly in phase with the 8200 cal yr anomaly in the 18o record gisp2 and ngrip of the greenland ice sheet the changes around 8450 cal yr bp compare well to the timing of the initial freshwater drainage of the proglacial lake agassiz therefore the proxy record of van mijenfjorden lends support to the theory explaining the 8200 cal yr bp event as a cumulative response to a freshwater forced reduction in the meridional overturning circulation in

environmental assessment from the sedimentary record of high latitude fiords the sedimentary record of fiords at high latitude where global change may be occurring earliest and will be greatest has the potential for assessment of environmental change at both low resolution the scale of millennia and high resolution decadal to less than daily unlike the lacustrine record which has been used very successfully in these studies the sedimentary processes and thus the sedimentary deposits of fiords differ 1 in the role of salt water in inhibiting mixing and promoting flocculation and through the role of sea ice 2 in the exchange of mass and energy with the much larger ocean beyond and 3 in the role of benthic biota in the sedimentary environment the work reviewed in this paper shows that fiord sediments are being used to assess sedimentary and oceanic processes as well as glacial periglacial and geomorphic history and that they are important proxies for long term climate and hydrology recommendations for advancing this work include long term monitoring of conditions in fiords and their drainage basins so that the transfer relations can be more solidly constructed from the proxy of fiord sediment integration of results from fiords in opposite polar latitudes and among proxies especially from lacustrine and ice core records will produce valuable insights assessment of the range of conditions in fiords from the most polar to temperate regions is important to building models of their processes and understanding of the paleoenvironmental signals that can be interpreted from each type

holocene climate variability although the dramatic climate disruptions of the last glacial period have received considerable attention relatively little has been directed toward climate variability in the holocene 11 500 cal yr b p to the present examination of similar to50 globally distributed paleoclimate records reveals as many as six periods of significant rapid climate change during the time periods 9000 8000 6000 5000 4200 3800 3500 2500 1200 1000 and 600 150 cal yr b p most of the climate change events in these globally distributed records are characterized by polar cooling tropical aridity and major atmospheric circulation changes although in the most recent interval 600 150 cal yr b p polar cooling was accompanied by increased moisture in some parts of the tropics several intervals coincide with major disruptions of civilization illustrating the human significance of holocene climate variability c 2004 university of washington all rights reserved

holocene changes in marine productivity and terrestrial organic carbon inputs into an icelandic fjord application of molecular and bulk organic proxies this study examines the dynamics of organic carbon contributions from different sources to the sediments of a 39 m core from isafjar ardjup fjord northwest iceland throughout the holocene furth

evidence of fluid seepage in gronfjorden spitsbergen implications from an integrated acoustic study of seafloor morphology marine sediments and tectonics abstract this study integrates high resolution surface and sub surface geophysical data to investigate possible fluid gas and or liquids migration pathways to the seafloor in gronfjorden west spitsbergen gronfjorden is an n s aligned tributary fjord located in the western part of the isfjorden fjord system pockmarks were identified on the bathymetric data in the southern and northern parts of the fjord three types of shallow seep related acoustic features have been identified in the marine sediments i enhanced reflections ii acoustic turbid zones and iii acoustic blankings they occur beneath some of the pockmarks and circular patches of high backscatter on the seafloor in the central part of the fjord which are potential seep related seafloor features 6 8 km long nnw sse striking ridges have been identified in the southern part of the study area thrust faults were interpreted on 2d multichannel seismic data truncating the triassic jurassic and cretaceous successions of western isfjorden located north of gronfjorden a possible link has been found between these fault systems and the seafloor ridges which strike in a similar direction further a normal fault has been identified within the shallow marine sediments which drapes the bedrock of the fjord the fractured bedrock of the fjord and faults associated with the west spitsbergen fold and thrust belt could possibly represent major conduits for fluid migration from deeper stratigraphy to shallow marine sediments and the seafloor

air temperature variations on the atlantic arctic boundary since 1802 1 a two hundred year instrumental record of annual surface air temperature in the atlantic arctic boundary region was reconstructed from four station based composite time series the new time series adds seventy six years to the previously available record credibility is supported by ice core records other temperature proxies and historical evidence this record provides new perspective on past climate fluctuations in a region where pivotal climate system processes occur and where unexplained low frequency variations were observed during the 20th century it is well correlated with sea surface temperature anomalies both regionally and in the vicinity of the north atlantic western boundary current and southern recirculation gyre the extended instrumental record reveals an irregular pattern of decadal scale temperature fluctuations over the past two centuries the early 20th century warming event is by far the most striking historical example

eight hundred year temperature variability from the norwegian continental margin and the north atlantic thermohaline circulation 1 four cores raised from the eastern norwegian sea and adjacent norwegian fjords at sites influenced by atlantic water have been investigated oxygen isotope analyses in benthic and planktonic foraminifera are used as a proxy for the paleotemperature development spanning the last 800 years the cores have been dated using a combination of 210pb and radiocarbon dates yielding time resolutions of 2 5 years for the last century and 9 25 years beyond this the proxy records have been compared with instrumental time series covering the last 100 years in order to validate the oxygen isotope measurements as a proxy for paleotemperature the comparison shows that the paleotemperature variability derived from the oxygen isotope analyses is generally similar to the amplitudes and trends seen in the instrumental time series in particular a cooling around 1905 1925 followed by a warming until 1955 is evident in all proxy records as well as in the instrumental time series beyond the last century the proxy records show two periods from 1225 1450 and 1650 1905 25 when temperatures were 1 3 1 6 c lower than present separated by a period of temperatures periodically comparable to present the last 80 years represent the modern warming and appear to be the warmest period of the last 800 years we find that that the ocean temperature variability is comparable to terrestrial reconstructions from the region implying a strong link in the ocean atmosphere climate system this suggests that the climate variability in this region beyond the period covered by instrumental time series was also associated with changes in the thermohaline circulation

main features of foraminiferal distribution reflecting estuarine hydrography in oslo fjord abstract foraminiferal assemblages have been analysed in sediment surface samples located along three profiles covering the depth interval 1 120 m in breidangen a wide basin forming the middle portion of oslo fjord the study concentrates on the distribution of major faunal features including suborders and diversities number of species shannon wiener index equitability in addition species distribution is recorded and q mode factor analysis has distinguished six assemblages measurements of hydrographical properties temperature salinity dissolved oxygen reveal the estuarine stratification of the water column which is reflected also by the faunal parameters on the basis of these features the following subdivision is proposed with increasing depth 1 seasonal layer dominated by calcareous species in the upper and agglutinated species in the lower part with low to intermediate diversities 2 transitional layer characterized by a maximum in diversity and a reduction in the agglutinated component 3 stable deeper water showing high diversity and a further decrease in the agglutinated component the generally higher frequency of calcareous foraminifera below the seasonal water layer on the eastern side of breidangen compared to the western side is mainly attributed to the influence of inflowing skagerrak water additionally it may be a result of increased supply of organic matter to the western side increasing the oxygen demand in this area

holocene relative sea level changes in a glacio isostatic area new data from south west scotland united kingdom abstract this paper contributes to knowledge of holocene relative sea level change along the mainland ayrshire coast and offshore isle of bute sw scotland uk where few such studies have previously been undertaken morphological studies mapping and altitude survey together with stratigraphical and biostratigraphical studies pollen and diatom analyses and radiocarbon dating disclose evidence for mid and late holocene relative sea level changes the main postglacial and blairdrummond displaced shorelines previously identified widely in mainland scotland are dated in the area at c 6800 calibrated years c 6000 14c years and c 4200 calibrated years c 3800 14c years bp respectively this information is compared with previously published information for scotland against the classical theoretical model of relative sea level change in areas of glacio isostasy for the mid and late holocene in conformity with the model a falling sequence of relative sea level changes near the centre of uplift is replaced by a rising sequence towards the periphery in which later shorelines overlap earlier ones in particular the blairdrummond shoreline which overlaps the earlier main postglacial shoreline is identified as the highest holocene shoreline over much of the coastline of scotland

modern sedimentary processes at the heads of martinez channel and steffen fjord chilean patagonia abstract chilean fjord sediments constitute high resolution archives of climate and environmental change in the southern andes to interpret such records accurately it is crucial to understand how sediment is transported and deposited within these basins this issue is of particular importance in glaciofluvial martinez channel and steffen fjord 48 s due to the increasing occurrence of glacial lake outburst floods glofs originating from outlet glaciers of the northern patagonian icefield hence the bathymetry of the head of martinez channel and steffen fjord was mapped at high resolution and the grain size and organic carbon content of grab sediment samples were examined results show that the subaquatic deltas of baker and huemules rivers at the head of martinez channel and steffen fjord respectively are deeply incised up to 36 m by sinuous channels the presence of sediment waves and coarser sediments within these channels imply recent activity and sediment transport by turbidity currents although several triggering mechanisms are possible we argue that elevated river discharge and the associated relatively high suspended sediment loads is the main cause of the occurrence of turbidity currents at the head of these fjords and are of key importance in shaping the fjord s subaquatic morphology this study shows that the heads of martinez channel and steffen fjord are dynamic sedimentary environments with rapidly migrating channels it highlights the importance of site selection and multi coring in any future project aimed at reconstructing environmental change using the sediments of either fjord

natural vs human induced facies changes in recent shallow fjord sediments of the store lungegardsvannet in bergen western norway a basin wide change from an older homogeneous bioturbated to a younger laminated facies occurs in sediments from the 26 m deep permanently anoxic store lungegardsvannet fjord the younger facies consists of alternating packages of light and dark layers each containing millimetre scale laminae the composition of the dark layers differs from that of the light layers in the occurrence of predominantly marine benthic diatoms larger grain size lower loss on ignition loi and lower trace metal cu pb zn concentrations total trace metal concentrations correlate with the redox sensitive trace elements mo and v r 0 8 and with loi r 0 6 the correlation of the minerogenic matter and the grain size related elements al and li is poor r 0 2 the shoaling of the sill depth and reduction of the fjord area resulting in the reduction of bottom water exchange accounted for the shift from bioturbated to laminated sediments during the end of the last century the alternating changes within the laminated facies are the result of alternating wind forces during years of calm wind conditions 1908 1919 and 1945 1961 undisturbed sedimentation of organic matter from primary production and an associated accumulation of trace metals prevail years of high wind force 1919 1945 and 1961 1991 trigger shore erosion and an increased influx of minerogenic matter

iron and manganese speciation and cycling in glacially influenced high latitude fjord sediments west spitsbergen svalbard evidence for a benthic recycling transport mechanism abstract glacial environments may provide an important but poorly constrained source of potentially bioavailable iron and manganese phases to the coastal ocean in high latitude regions little is known about the fate and biogeochemical cycling of glacially derived iron and manganese in the coastal marine realm sediment and porewater samples were collected along transects from the fjord mouths to the tidewater glaciers at the fjord heads in smeerenburgfjorden kongsfjorden and van keulenfjorden along western svalbard solid phase iron and manganese speciation determined by sequential chemical extraction could be linked to the compositions of the local bedrock and hydrological weathering conditions below the local glaciers the concentration and sulfur isotope composition of chromium reducible sulfur crs in kongs and van keulenfjorden sediments largely reflect the delivery rate and isotope composition of detrital pyrite originating from adjacent glaciers the varying input of reducible iron and manganese oxide phases and the input of organic matter of varying reactivity control the pathways of organic carbon mineralization in the sediments of the three fjords high reducible iron and manganese oxide concentrations and elevated metal accumulation rates coupled to low input of fresh organic matter lead to a strong expression of dissimilatory metal oxide reduction evidenced in very high porewater iron up to 800 m and manganese up to 210 m concentrations in kongsfjorden and van keulenfjorden sediment reworking by the benthic macrofauna and physical sediment resuspension via iceberg calving may be additional factors that promote extensive benthic iron and manganese cycling in these fjords on going benthic recycling of glacially derived dissolved iron into overlying seawater where partial re oxidation and deposition occurs facilitates the transport of iron across the fjords and potentially into adjacent continental shelf waters such iron dominated fjord sediments are likely to provide significant fluxes of potentially bioavailable iron to coastal waters and beyond by contrast low delivery of reducible iron oxyhydr oxide phases and elevated organic carbon mineralization rates driven by elevated input of fresh marine organic matter allow organoclastic sulfate reduction to dominate carbon remineralization at the outer smeerenburgfjorden sites which may limit iron fluxes to the water column

late quaternary glacial to postglacial sedimentation in three adjacent fjord lakes of the quebec north shore eastern canadian shield abstract high resolution swath bathymetry imagery allowed mapping in great detail the sublacustrine geomorphology of lakes pentecote walker and pasteur three deep adjacent fjord lakes of the quebec north shore eastern canada these sedimentary basins have been glacio isostatically uplifted to form deep steep sided elongated lakes their key geographical position and limnogeological characteristics typical of fjords suggest exceptional potential for long term high resolution paleoenvironmental reconstitutions acoustic subbottom profiles acquired using a bi frequency chirp echosounder 3 5 12 khz together with cm and m long sediment core data reveal the presence of four acoustic stratigraphic units the acoustic basement unit 1 represents the structural bedrock and or the ice contact sediments of the laurentide ice sheet and reveals v shaped bedrock valleys at the bottom of the lakes occupied by ice loaded sediments in a basin fill geometry unit 2 moraines observed at the bottom of lakes and in their structural valleys indicate a deglaciation punctuated by short term ice margin stabilizations following ice retreat and their isolation the fjord lakes were filled by a thick draping sequence of rhythmically laminated silts and clays unit 3 deposited during glaciomarine and or glaciolacustrine settings these sediments were episodically disturbed by mass movements during deglaciation due to glacial isostatic rebound ams 14c dating reveal that the transition between deglaciation of the lakes pentecote and walker watersheds and the development of para and post glacial conditions occurred around 8000 cal bp the development of the lake head river delta plain during the holocene provided a constant source of fluvial sediment supply to the lakes and the formation of turbidity current bedforms on the sublacustrine delta slopes the upper sediment succession i e 4 6 5 m consists of a continuous para to post glacial sediment drape unit 4 that contains laminated and massive sediment and series of rapidly deposited layers these results allow establishing a conceptual model of how a glaciated coastal fjord evolves during and after deglaciation in a context of rapid glacio isostatically induced forced regression

comparison of the auroral e region neutral winds derived with the european incoherent scatter radar and predicted by the national center for atmospheric research thermosphere ionosphere mesosphere electrodynamics general circulation model a comparison study of the auroral e region neutral wind has been conducted using the european incoherent scatter eiscat radar observations and thermosphere ionosphere mesosphere electro dynamics general circulation model time gcm predictions the daily mean wind data as well as diurnal and semidiurnal tidal wind data are compared for the three seasons summer equinox and winter between 95 and 119 km fairly good agreement is found in the altitude profile of the mean zonal wind between the eiscat observation and the time gcm prediction for summer indicating the parameterization of gravity waves employed in the time gcm is adequate for this feature the meridional mean wind amplitude predicted by the time gcm is considerably smaller than that observed by eiscat and the predicted wind is slightly northward for all the seasons above 100 km generally good agreement is found for the amplitude of the diurnal tide especially the summer prediction while disagreements between the model and observational results are found for the corresponding phases the semidiurnal amplitude predicted by the time gcm is much smaller than that observed by eiscat and relatively large differences of the semidiurnal phase between the observations and predictions are found for all seasons these comparison results suggest that further advancements in the gravity wave parameterization as well as the addition of planetary wave effects are needed to predict more realistic lower thermospheric winds at high latitude

cyclic sedimentation produced by fluctuations in meltwater discharge tides and marine productivity in an alaskan fjord glacimarine sediment deposited in the fjord adjacent to muir glacier in south eastern alaska consists of rhythmically laminated muds stratified sandy mud sand and gravelly mud facies cyclicity is recorded by gravelly mud facies deposited during winter by ice rafting black mud laminae formed by spring plankton blooms and variations in tidal rhythmite thickness and texture produced by the interaction of meltwater discharges and tidal currents in the macrotidal fjord regular cyclicity in laminae thickness is tested statistically by fourier transform and can be attributed to a lunar tidal cycle control in the five cores collected up to 6 km from the sediment source cores close to the source can have additional laminae as a result of discharge fluctuations and distal cores may lack full cycles because of variability in the plume path and attenuation with distance cyclic variations in sediment texture are recorded in magnetic susceptibility ms profiles of the cores high ms values are produced by turbidite sand beds or by stratified sandy mud deposited by overflow plumes during peak summer meltwater discharge low values reflect muddy intervals deposited during periods of low meltwater discharge such as during autumn and winter sediment accumulation rates measured by 210pb dating range from 82 cm year 1 2 km from the sediment source at the head of the fjord to 16 cm year 1 6 km away these rates are within the same range as average sediment accumulation rates determined from cyclic seasonal markers within the cores these data show that with careful documentation annual cycles of glacimarine sediment accumulation can be detected within marine cores cores collected from the distal portion of the basin were deposited during the transition of muir glacier from a tidewater terminus ending in deep water to a terrestrial glacier with an ice contact delta deposited in front of the terminus this transition is recorded by a coarsening upward sedimentary sequence formed by turbidite sands originating from the prograding delta above fine grained laminated basin fill deposited by turbid overflow plumes

a signal of persistent atlantic multidecadal variability in arctic sea ice satellite data suggest an arctic sea ice climate system in rapid transformation yet its long term natural modes of variability are poorly known here we integrate and synthesize a set of multicentury historical records of atlantic arctic sea ice supplemented with high resolution paleoproxy records each reflecting primarily winter spring sea ice conditions we establish a signal of pervasive and persistent multidecadal 60 90 year fluctuations that is most pronounced in the greenland sea and weakens further away covariability between sea ice and atlantic multidecadal variability as represented by the atlantic multidecadal oscillation amo index is evident during the instrumental record including an abrupt change at the onset of the early twentieth century warming similar covariability through previous centuries is evident from comparison of the longest historical sea ice records and paleoproxy reconstructions of sea ice and the amo this observational evidence supports recent modeling studies that have suggested that arctic sea ice is intrinsically linked to atlantic multidecadal variability this may have implications for understanding the recent negative trend in arctic winter sea ice extent although because the losses have been greater in summer other processes and feedbacks are also important

115 year ice core data from akademii nauk ice cap severnaya zemlya high resolution record of eurasian arctic climate change from 1999 to 2001 a 724 m deep ice core was drilled on akademii nauk ice cap severnaya zemlya to gain high resolution proxy data from the central russian arctic despite strong summertime meltwater percolation this ice core provides valuable information on the regional climate and environmental history we present data of stable water isotopes melt layer content and major ions from the uppermost 57 m of this core covering the period 1883 1998 dating was achieved by counting seasonal isotopic cycles and using reference horizons multi annual 18 o values reflect eurasian sub arctic and arctic surface air temperature variations we found strong correlations to instrumental temperature data from some stations e g r 0 62 for vardo northern norway the 18 o values show pronounced 20th century temperature changes with a strong rise about 1920 and the absolute temperature maximum in the 1930s a recent decrease in the deuterium excess time series indicates an increasing role of the kara sea as a regional moisture source from the multi annual ion variations we deduced decreasing sea salt aerosol trends in the 20th century as reflected by sodium and chloride whereas sulphate and nitrate are strongly affected by anthropogenic pollution

observations of the phase locked 2 day wave over the australian sector using medium frequency radar and airglow data 1 the quasi 2 day wave with a nominal mean period just above 50 h is a significant feature of the 80 100 km altitude region in both hemispheres it becomes particularly prominent in the southern hemisphere summer at midlatitudes where a short time after summer solstice its amplitude rapidly increases and its mean period is found to be approximately 48 h producing an oscillation phase locked in local time this lasts for a few weeks presented here are observations of the meridional winds and airglow over two sites in australia for 4 years during the austral summers of 2003 2006 we show that during those times when the large amplitude phase locked 2 day wave pl tdw is present the diurnal tide greatly decreases this is consistent with the walterscheid and vincent 1996 model in which the pl tdw derives its energy from a parametric excitation by the diurnal tide these data also show that the diurnal tide is more suppressed and the pl tdw amplitude is larger in odd numbered years suggesting a biannual effect the airglow data indicated that for the pl tdw the winds and temperature are nearly out of phase when the pl tdw is present airglow amplitudes can become quite large a result dependent on the local time of the pl tdw maximum the airglow intensity response was in general much larger than what would be expected from the airglow temperature response suggesting that the pl tdw is causing a significant composition change possibly due to minor constituent transport