the biogeochemistry of aluminum in the pacific ocean abstract vertical distributions and horizontal surface transects of dissolved and particulate al at several locations in the pacific ocean are presented here concentrations of dissolved al in the pacific range from 0 3 to 5 nmol kg in the surface waters from 0 1 to 1 nmol kg in mid depths and from 0 5 to 2 nmol kg in the deep waters from these data and published data from other regions it is evident that al has a unique oceanic chemistry relative to that of other metals external sources and rapid particle scavenging throughout the water column are the major controls on dissolved al distributions in the oceans vertical profiles generally exhibit a surface maximum a mid depth minimum and increasing concentrations toward the sediment water interface this suggests two sources of dissolved al one to the surface waters and one to the deep waters concentrations of dissolved al in surface waters are lowest within the eutrophic low salinity california current 0 3 1 nmol kg and increase westwardly into the subtropical gyre of the north pacific 5 nmol kg values in the south pacific gyre are fivefold lower these horizontal trends indicate that the primary source of dissolved al to the surface waters of the central pacific is from eolian input dissolved al supplied by rivers to the eastern north pacific appears to be rapidly scavenged in estuaries and or the highly productive coastal region the source of dissolved al to the deep waters is not known but could be due to a flux out of the sediments or a remineralization process suspended particulate al concentrations increase with depth at all stations and decrease with distance from the ocean boundary surface values range from 1 5 nmol kg near shore to 0 3 nmol kg in the central gyres of the pacific deep water concentrations range from 22 nmol kg near shore to 4 nmol kg in the north pacific central gyre and decrease to 1 3 nmol kg in the south pacific central gyre observed distributions indicate that suspended particulate al varies with the intensity of bottom sediment resuspension and the horizontal mixing of the resulting nepheloid layer out from ocean boundary regions particle residence times estimated are consistent with other reported values

biogeochemical and physical factors influencing seawater ƒco2 and air sea co2 exchange on the bermuda coral reef it is uncertain whether coral reef ecosystems are oceanic sources or sinks of carbon dioxide co2 understanding the complex interactions between biogeochemical and physical processes within reef ecosystems is important for determining the contribution of coral reefs to the global carbon cycle and the air sea flux of co2 the influence of biogeochemical and physical processes on co2 cycling was examined for 1 month at hog reef flat part of the rim reef of bermuda the fugacity of seawater co2 co2 was measured hourly by use of a carbon interface ocean atmosphere buoy providing the longest time series of seawater co2 data on a coral reef ecosystem seawater co2 ranged from 340 to 470 atm with a diurnal variability ranging from 20 60 atm air sea co2 was directed from ocean to atmosphere with a mean flux of 3 3 4 6 mmoles co2 m 2 d 1 the reef data are compared with a seawater co2 time series collected at the u s joint global ocean flux study bermuda atlantic time series study bats site 31 50 n 64 10 w in the sargasso sea surrounding bermuda sargasso sea waters are the original source for bermuda platform water providing a context for understanding the biogeochemical modification of reef water at hog reef flat seawater fco2 at hog reef flat was elevated relative to the sargasso sea by 0 to 120 atm primarily as a result of calcium carbonate production however the ability of the reef to act either as a source or sink of co2 to from the atmosphere largely depended on the air sea co2 disequilibrium of offshore sargasso sea waters impinging on the reef site this study also revealed that an assessment of the fate of co2 on coral reefs is dependent on understanding the reef s physical regime and forcing the dynamics of wind tide platform circulation and fluxes of offshore or onshore waters are necessary context for all coral reef sites

advances in marine chemistry 1979 1982 these four years saw advances in many areas further developments in sampling and analytical techniques have opened new avenues of exploration for trace elements and particulate matter the impact of the geosecs expedition was further felt in the field of marine chemistry as the results were still being published a major field effort occurred as a follow on to the geosecs work tto and intensive sampling was performed in the newly discovered submarine hydrothermal vent fields an important and unresolved controversy has arisen regarding the ability to measure preformed co2 in the seawater system in many respects the field of marine chemistry appears to be gaining a momentum spurred by both improvements in analytic techniques and an increasing social and economic relevance

elliptical diagnostics of stratospheric polar vortices diagnostics based on the spatial moments of isopleths of a long lived tracer or of potential vorticity are presented that enable the structure and evolution of stratospheric polar vortices to be concisely summarized and quantified the area centre aspect ratio and orientation of the equivalent ellipse of the vortex on an isentropic surface are defined using the second and lower order spatial moments of contours within the vortex edge region by examining the variations of these elliptical diagnostics with time and altitude the temporal evolution and vertical structure of the polar vortices can be quantified the usefulness of the diagnostics is assessed by examining nitrous oxide data from the geophysical fluid dynamics laboratory skyhi general circulation model the diagnostics show and quantify several differences between the arctic and antarctic vortices in the skyhi model the arctic vortex moves further off the pole is generally more elongated and has a more complicated vertical structure than the antarctic vortex with larger variations of both the vortex centre and elongation with height the elliptical diagnostics also identify the occurrence of large scale rossby wave breaking events both at the vortex edge and in the subtropics in the model

diagenesis of dissolved aluminum in organic rich estuarine sediments abstract the sedimentary geochemistry of dissolved al is complicated by a number of different reactions in this study we show that complexation by organic matter adsorption to fe oxyhydroxides and reaction with si in solution have important effects on the distribution of dissolved al in sediments in the absence of physical resuspension of sediment into overlying waters dissolved al is rapidly consumed at the sediment water interface and is subsequently released upon reduction of fe oxyhydroxides this release does not cause noticeable perturbations in dissolved al concentrations in sediments because of rapid consumption reactions which mask the true mobility of al results suggest that one of the consumption reactions may be due to formation of an fe al silicate the amount of authigenic aluminosilicate formed in estuarine sediments must be very small relative to the detrital component in the deep sea however the long residence time of fe oxyhydroxides at the sediment water interface with resulting greater accumulation of adsorbed al may explain the abundance of al in fe smectites reported from many different areas

retention of riverine iron in estuaries abstract retention of fe flocs resulting from the mixing of river water and seawater was examined in three maine estuaries riverine fe was found to remain fairly conservative with salinity implying that the process of floccufation does not necessarily remove fe from water parcels laboratory experiments corroborated the field data by demonstrating that neither gravity nor suspended sediment were very effective in removing flocculated fe from suspension however input of a tannery effluent did appear to result in scavenging of fe from estuarine waters flocculated riverine fe was found to increase considerably the fe concentrations of estuarine bottom sediments with the amount of iron per sediment specific surface area dependent on mean river flow entering an estuary while no long term retention efficiencies could be calculated for these estuaries it seems likely that a significant portion of flocculated riverine fe escapes to shelf waters

the distribution of aluminium in the greenland sea and its relationship to ventilation processes during two cruises to the greenland sea in 1988 and 1989 a total of 690 on board aluminium al determinations were performed on samples collected from profiles located along four transects in the greenland sea as part of the greenland sea project al concentrations range from extremely low values 0 4 nm in the polar waters of the east greenland current draining the arctic ocean to 17 9 nm in the newly formed norwegian sea deep water nsdw at the periphery of the greenland gyre the al content in the component water masses serves to constrain the make up of these water masses from the various mixing products of the region the enrichment of al in the nsdw both at its site of formation within the greenland sea up to 17 9 nm and in the lofoten basin of the norwegian sea up to 40 3 nm leads to the conclusion that there must be an additional external source of al to these water masses the apparent inability of water column or sedimentary diagenetic processes to provide this enrichment and the observation of enriched al values associated with a high salinity shelf brine leads us to the conclusion that these brines may be responsible for the observed enrichments the high concentration of al in the greenland sea deep water compared with the water masses that produce it suggests that al may be acting as an inverse tracer of the processes that ventilate this basin by convective overturn i e the al concentration which increases with time as a result of continuous brine or other external inputs is reduced during convective events it is also argued that this flushing of elevated al water during convective events may have a similar counterpart in the iceland sea and that this mechanism could go some way toward solving the al deficit that exists between the enriched north atlantic deep water and its depleted precursor water masses observed in the intermediate waters of the greenland and iceland seas

characterizing stratospheric polar vortex variability with computer vision techniques computer vision techniques are used to characterize the arctic stratospheric polar vortex in 38 years of reanalysis data such techniques are typically applied to analyses of digital images but they represent powerful tools that are more widely applicable basic techniques and considerations for geophysical applications are outlined herein segmentation descriptive and tracking algorithms are combined in the characterization and analysis of vortex evolution using algorithms for region tracking cave art package which was developed to comprehensively describe dynamical and geometrical evolution of polar vortices cave art can characterize and track multiple vortex regions through time providing an extensive suite of region moments and edge diagnostics for each cave art is valuable for identifying vortex splitting events including but not limited to previously cataloged vortex split sudden stratospheric warmings an algorithm for identifying such events detects 52 potential events between 1980 2017 of these 38 are subjectively classified as distinct split like events the algorithm based on cave art is also compared with moments based methods previously used to detect split events furthermore vortex edge averaged windspeeds from cave art are used to define extreme weak and strong polar vortex events over multiple vertical levels this allows characterization of their occurrence frequencies and extents in time and altitude weak and strong events show distinct signatures in cave art diagnostics in contrast to weak events strong vortices are more cylindrical and pole centered and less filamented than the climatological state these results from cave art exemplify the value of computer vision techniques for analysis of geophysical phenomena

a temporal and spatial study of mudflat erosion and deposition sediment elevations were measured on an intertidal mudflat in maine to determine the temporal and spatial changes in sediment volume the winter and spring months were times of greatest sediment change with erosion in winter months followed by rapid accretion in the spring in some months erosion and deposition took place during the same time interval but on different parts of the mudflat the data suggest that areas of erosion quickly become sites of accretion indicating that an equilibrium surface level is being maintained mudflats may strongly influence the adjacent estuary by acting as sediment banks that can periodically lend sediments to the particulate pool offshore we conclude that mudflats should not be thought of as steady accretionary environments but rather as more variable environments that respond to seasonal changes

the diurnal and latitudinal variation of auroral zone ionospheric conductivity the great spatial and temporal variability of auroral ionospheric conductivity significantly influences the ionospheric closure path for high latitude field aligned currents because these closure paths can extend to low latitudes changes in auroral zone conductivity can influence the global electric field distribution in this paper synoptic chatanika radar observations of auroral zone conductivity that cover 62 to 68 geomagnetic latitude are presented they are representative of quiet winter active winter and equinoctial conditions during the daytime the solar contribution to the height integrated conductivity is well represented by p h 5 10 cos1 2 where is the solar zenith angle the nighttime height integrated pedersen and hall conductivities p and h in the electron density trough are at times below our detection threshold of 0 5 mho following magnetic substorm onset enhanced conductivity regions move southward and intensify as the recovery phase begins the conductivity pattern recedes northward and diminishes the onset and cessation of precipitation associated with these events can be as abrupt as a few minutes in one example the behavior of p and h are examined in the vicinity of the harang discontinuity which was quite sharp 30 min in local time at the harang discontinuity on that day the ratio of h to p decreased indicating a softening of the precipitating energy distribution

a climatology of stratospheric polar vortices and anticyclones 1 united kingdom meteorological office global analyses from 1991 to 2001 are used to create a global climatology of stratospheric polar vortices and anticyclones new methodologies are developed that identify vortices in terms of evolving three dimensional 3 d air masses a case study illustrates the performance of the identification schemes during february and march of 1999 when a merger of anticyclones led to a stratospheric warming that split the arctic polar vortex the 3 d structure and temporal evolution of the arctic vortex and identified anticyclones demonstrates the algorithm s ability to capture complicated phenomena the mean geographical distribution of polar vortex and anticyclone frequency is shown for each season the frequency distributions illustrate the climatological location and persistence of polar vortices and anticyclones a counterpart to the aleutian high is documented in the southern hemisphere the australian high the temporal evolution of the area occupied by polar vortices and anticyclones in each hemisphere is shown as a function of potential temperature large polar vortex area leads to an increase in anticyclone area which in turn results in a decrease in the size of the polar vortex during northern winter and southern spring 9 years of daily anticyclone movement are shown on the 1200 k 36 km 4 hpa isentropic surface preferred locations of anticyclogenesis are related to cross equatorial flow and weak inertial stability regimes of traveling and stationary anticyclones are discussed index terms 3309 meteorology and atmospheric dynamics climatology 1620 3319 meteorology and atmospheric dynamics general circulation 3334 meteorology and atmospheric dynamics middle atmosphere dynamics 0341 0342 keywords polar vortex stratospheric anticyclones

distribution of trace metals in anchialine caves of adriatic sea croatia abstract this study presents results of the first comprehensive research on ecotoxic trace metals cd pb cu and zn in aquatic anchialine ecosystems data show the influence of hydrological and geological characteristics on trace metals in highly stratified anchialine water columns distribution of cd pb cu and zn in two anchialine water bodies bjejajka cave and lenga pit in the mljet national park croatia were investigated seasonally from 2006 to 2010 behaviour and concentrations of dissolved and total trace metals in stratified water columns and metal contents in sediment carbonate rocks and soil of the anchialine environment were evaluated trace metals and dissolved organic carbon doc concentrations in both anchialine water columns were significantly elevated compared to adjacent seawater zn and cu concentrations were the highest in the lenga pit water column and sediment elevated concentrations of zn pb and cu in bjejajka cave were mainly terrigenous significantly elevated concentrations of cadmium up to 0 3 g l 1 were found in the water column of bjejajka cave almost two orders of magnitude higher compared to nearby surface seawater laboratory analysis revealed that bat guano was the major source of cadmium in bjejajka cave cadmium levels in lenga pit which lacks accumulations of bat guano were 20 fold lower moreover low metal amounts in carbonate rocks in both caves combined with mineral leaching experiments revealed that carbonates play a minor role as a source of metals in both water columns we observed two types of vertical distribution pattern of cadmium in the stratified anchialine bjejajka cave water column at lower salinities non conservative behaviour was characterized by strong desorption and enrichment of dissolved phase while at salinities above 20 cd behaved conservatively and its dissolved concentration decreased conservative behaviour of cu pb zn and doc was observed throughout the water column after heavy rains cd showed reduced concentration and uniform vertical distribution suggesting a non terrestrial origin under the same conditions concentrations of total and dissolved pb cu zn and doc were significantly elevated variations of trace metal vertical distributions in anchialine water columns were caused by large inputs of fresh water extraordinary rainy events and were not influenced by seasonal changes

iron isotope systematics in estuaries the case of north river massachusetts usa abstract recent studies have suggested that rivers may present an isotopically light fe source to the oceans since the input of dissolved iron from river water is generally controlled by flocculation processes that occur during estuarine mixing it is important to investigate potential fractionation of fe isotopes during this process in this study we investigate the influence of the flocculation of fe rich colloids on the iron isotope composition of pristine estuarine waters and suspended particles the samples were collected along a salinity gradient from the fresh water to the ocean in the north river estuary ma usa estuarine samples were filtered at 0 22 m and the iron isotope composition of the two fractions dissolved and particles were analyzed using high resolution mc icp ms after chemical purification dissolved iron results show positive 56 fe values with an average of 0 43 0 04 relative to the irmm 14 standard and do not display any relationships with salinity or with percentage of colloid flocculation the iron isotopic composition of the particles suspended in fresh water is characterized by more negative 56 fe values than for dissolved fe and correlate with the percentage of fe flocculation particulate 56 fe values vary from 0 09 at no flocculation to 0 1 at the flocculation maximum which reflect mixing effects between river borne particles lithogenic particles derived from coastal seawaters and newly precipitated colloids since the process of flocculation produces minimal fe isotope fractionation in the dissolved fe pool we suggest that the pristine iron isotope composition of fresh water is preserved during estuarine mixing and that the value of the global riverine source into the ocean can be identified from the fresh water values however this study also suggests that 56 fe composition of rivers can also be characterized by more positive 56 fe values up to 0 3 relative to the crust than previously reported in order to improve our current understanding of the oceanic iron isotope cycling further work is now required to determine the processes controlling the fractionation of fe isotopes during continental run off

subtropical stratospheric mixing linked to disturbances in the polar vortices randel et al 1 have observed tongues of stratospheric air stretching from the tropics into middle latitudes and conclude that such events may be responsible for transporting significant amounts of stratospheric air across the tropical mid latitude barrier2 here i examine the movements of air parcels during these events using high resolution contour trajectory calculations my calculations suggest that the tongues of tropical air are associated with disturbances of the stratospheric polar vortices the edge of the disturbed polar vortex reaches low latitudes and draws a long tongue of tropical air around the vortex into middle latitudes this process occurs in the winter of both hemispheres although the edge of the larger antarctic polar vortex reaches farther toward the equator and draws up material from lower latitudes than its arctic counterpart

intrusions into the lower stratospheric arctic vortex during the winter of 1991 1992 investigations of the kinematics of the lower stratospheric arctic vortex during the winter of 1991 1992 using the contour advection with surgery technique reveal three distinct events in which there was substantial intrusion of midlatitude air into the vortex in apparent contradiction of the view that the polar vortex constitutes an isolated air mass two of these events in late january and mid february were well documented they were predicted in high resolution forecasts by the european centre for medium range weather forecasts most clearly in experimental forecasts with reduced diffusion direct confirmation of the presence of the intrusions and of their calculated locations was provided by aerosol observations from the airborne differential absorption laser lidar aboard the nasa dc 8 taken as part of the second airborne arctic stratospheric expedition campaign aerosol rich air of midlatitude origin was seen in the expected position of the intrusions the reality of the february event was also confirmed by in situ measurements from the nasa er 2 such events may be significant for the chemical processes taking place within the winter vortex the intrusions were evidently related to the meteorology of the northern stratosphereduring this winter and in particular to persistent tropospheric blocking over the northeastern atlantic ocean and western europe and concomitant ridging into the lower stratospheric vortex in this region nevertheless preliminary investigations have indicated that such events are not uncommon in other northern hemisphere winters although no such events were found in the southern hemisphere during the antarctic winter of 1987

anomalous neon helium ratios in the arctic ocean measurements of dissolved helium and neon were made on seawater samples collected at the lomonosov ridge experiment site lorex 1979 and at the fram iii drifting ice station 1981 in the arctic ocean the most striking feature of the results is the high values of ne he in the shallow depths compared to previous results in other oceans ice formation and refreezing of meltwater appear to be the mechanisms which could explain the observed ne he anomaly

entrainment of trace metal enriched atlantic shelf water in the inflow to the mediterranean sea surface waters of the mediterranean sea have higher trace metal concentrations than open atlantic surface waters1 this observation could be explained by sources within the basin but recent data from the alboran sea2 indicate that trace metals may already be enriched in atlantic waters flowing into the mediterranean through the strait of gibraltar here we present new data documenting the presence of trace metal enriched source waters west of the strait and present a mathematical analysis showing that cu ni cd and zn distributions in the alboran sea can be explained as linear mixtures of four well defined sources 1 spanish coastal waters 2 north atlantic central water 3 atlantic surface water and 4 mediterranean levantine intermediate water in this analysis salinity and trace metals are used for the first time to deconvolve mixing between water masses of different origins

iron isotope fractionation in subterranean estuaries dissolved fe concentrations in subterranean estuaries like their river seawater counterparts are strongly controlled by non conservative behavior during mixing of groundwater and seawater in coastal aquifers previous studies at a subterranean estuary of waquoit bay on cape cod usa demonstrate extensive precipitation of groundwater borne dissolved ferrous iron and subsequent accumulation of iron oxides onto subsurface sands waquoit bay is thus an excellent natural laboratory to assess the mechanisms of fe isotope fractionation in redox stratified environments and determine potential fe isotope signatures of groundwater sources to coastal seawater here we report fe isotope compositions of iron coated sands and porewaters beneath the intertidal zone of waquoit bay the distribution of pore water fe shows two distinct sources of fe one residing in the upward rising plume of fe rich groundwater and the second in the salt wedge zone of pore water the groundwater source has high fe ii concentration consistent with anoxic conditions and yield 56fe values between 0 3 and 1 3 in contrast sediment porewaters occurring in the mixing zone of the subterranean estuary have very low 56fe values down to 5 these low 56fe values reflect fe redox cycling and result from the preferential retention of heavy fe isotopes onto newly formed fe oxyhydroxides analysis of fe oxides precipitated onto subsurface sands in two cores from the subterranean estuary revealed strong 56fe and fe concentration gradients over less than 2m yielding an overall range of 56fe values between 2 and 1 5 the relationship between fe concentration and 56fe of fe rich sands can be modeled by the progressive precipitation of fe oxides along fluid flow through the subterranean estuary these results demonstrate that large scale fe isotope fractionation up to 5 can occur in subterranean estuaries which could lead to coastal seawater characterized by very low 56fe values relative to river values

the distribution of fe in the antarctic circumpolar current abstract the large scale distributions of dissolved and total fe in surface and deep waters of the antarctic circumpolar current exhibit strong relationships with hydrography and biological processes the mean dissolved fe concentrations are low in surface waters of the antarctic circumpolar current 0 31 0 49 nm with a minimum of 0 17 nm and higher averaging 1 11 9 nm in the polar frontal region enhanced dissolved surface water concentrations in the polar frontal region are attributed to input from the continental shelf and coincide with phytoplankton spring blooms of large diatoms the effects of sea ice melting and iceberg melting on the fe concentrations were relatively small dissolved deep water concentrations 400 m in the antarctic circumpolar current ranged from 0 4 to 2 8 nm circumpolar deep water has relatively high dissolved fe concentrations in the polar frontal region 0 4 2 8 nm compared with deep waters further to the south 0 6 1 1 nm similarly total dissolvable unfiltered fe concentrations in the upper circumpolar deep water tend to decrease southward from the polar frontal region in the lower circumpolar deep water total dissolvable fe concentrations are higher than in the upper circumpolar deep water due to the existing nepheloid layer and sources on the mid atlantic ridge dissolved and total dissolvable fe concentrations in the antarctic bottom water are higher than those of other water masses in the antarctic circumpolar current consistent with the nepheloid layer as well as diagenetic input from shelf sediments the high nutrient low chlorophyll areas of the antarctic ocean and northeast pacific ocean have different major fe input sources of similar magnitude in the antarctic circumpolar current upward transport of fe is the main input source whereas in the north pacific ocean aerosols are the dominant source

the stratospheric major warming of winter 1984 85 observations and dynamical inferences the evolution and dynamics of the major stratospheric warming of 1984 85 are described and discussed using synoptic maps of geopotential height and temperature fields of q vectors isentropic maps of ertel s potential vorticity and diagnostics based on zonal averaging and departures therefrom it is argued that the stratosphere cannot be regarded as being pre conditioned before the warming in the conventional sense of the term and that an important element of the warming was that the flow was highly asymmetric at the onset of the rapid breakdown of stratospheric westerlies nonlinear dynamics was involved as evidenced by an anticorrelation in time between the amplitudes of zonal waves 1 and 2 by the magnitude of a nonlinear term compared with those of linear terms in a governing equation and by the irreversible rearrangement of potential vorticity apparent loss of potential vorticity in the stratosphere is associated in part with differential advection of air in a vertically sheared flow salient features of the large scale flow in the troposphere during the stratospheric warming are noted

three dimensional transport of the ertel potential vorticity and n2o in the gfdl skyhi model abstract in this study the author investigates the 3d evolution of the ertel potential vorticity pv and n2o in northern hemisphere winter from 1 to 10 february of model year 1984 in the gfdl skyhi model the diagnosis was done on three isentropic surfaces 800 450 and 320 k by using output from the gfdl skyhi model which has 1 2 1 horizontal resolution 40 layers in vertical and 60 s time resolution the data output was taken twice daily the high resolution lagrangian field advection model fam which has no diabatic heating and diffusion is used to study the evolution of these two fields the 1 1 resolution in fam gives reasonable results the following results are found 1 in the stratosphere there are two kinds of barriers that is subtropical barrier and polar barrier for both pv and n2o the existence of the subtropical barrier is coincident with the subtropical jet the subtropical barrier is more permeable than the polar barrier even though the tropopause acts like a barrier the

scientific results of the u s ims ground based program the scientific results of the u s international magnetospheric study ims ground based program available to the author up to february 1982 are summarized included are results derived from 1 magnetometers of the ims meridian chains 2 incoherent scatter radars 3 a balloon campaign and 4 optical spectroscopic observations a large body of data obtained during the ims remains to be analyzed and published

influence of provenance weathering and sedimentary processes on the elemental ratios of the fine grained fraction of the bedload sediments from the vembanad lake and the adjoining continental shelf southwest coast of india abstract geochemical studies comprising twelve major elements and twenty four trace elements including the rare earth elements ree have been carried out on the concentrations normalized to the average upper continental crust ucc show that the sediments studied are depleted in rb k ba ta hf na and ca and enriched in cs u th rees sc fe co and cr ucc normalized patterns are strikingly similar for all the three sediment types probably because of efficient mixing of sedimentary material during weathering transport and deposition the depletion of na k ca and ba in sediments relative to ucc could be attributed to their mobility during weathering the depletion of ta and hf and enrichment of th ree and sc are probably related to provenance characteristics and enrichment of u is attributed to oxidation reduction processes shale normalized ree values reveal steep hree patterns tbsample tbshale ybsample ybshale lasample lashale smsample smshale and flat lree patterns the shale normalized patterns for all the three types of sediments are remarkably similar with variations in the magnitude of lree enrichment lan ybn varies between 1 72 to 2 57 times that of paas lree enrichment and steep hree patterns are attributed to felsic source rock characteristics other geochemical characteristics such as high la th and low la sc and th sc ratios compared to ucc also support a felsic provenance eu eu values for all the three types are little more than 1 which is also a characteristic feature of archean crust furthermore data plotted on discrimination diagrams of la th vs hf and la th sc cluster closer to granite and away from basalt and komatiite and are consistent with source rock geology geochemical data have also helped in ascertaining the weathering trends the chemical index of alteration cia has been used to quantify the degree of weathering cia values range between 81 and 94 on a scale of 40 100 indicating a high degree of alteration fluvial sediments seem to be more altered on an a cn k diagram the data fall closer to the compositional fields of highly weathered minerals kaolinite gibbsite and chlorite a high degree of weathering is also indicated by other plots such as k2o fe2o3 al2o3 and log k vs log rb the geochemical data are consistent with the studies on clay mineralogy higher kaolinite carried out by other authors on the sediments of the same area secondary processes seem to affect other geochemical discriminants such as co cr ni and u as revealed by plots of 1 la sc vs co th and 2 th hf co and co th cr th ratios and makes them unsuitable for determining provenance and tectonic setting

dissolved al in sediments and waters of the east china sea implications for authigenic mineral formation abstract numerous previous studies indicate that several different authigenic aluminosilicates form in the oceans in this study we show using dissolved al distributions in sediments and waters from the nearshore regions of the east china sea that the process of aluminosilicate formation probably begins rapidly upon contact of detrital clays with seawater statistical analyses of dissolved al si h relations in surface sediments indicate that the minerals forming in east china sea sediments low in dissolved fe are dioctahedral chlorites with an average composition ex 0 91 mg 0 77 al 5 0 si 2 7 o 10 oh 8 where ex exchangeable 1 cation this composition is also consistent with dissolved al and si measurements as a function of salinity in turbid overlying waters results suggest a dissolution reprecipitation mechanism for clay mineral reconstitution this mechanism can help to explain why different authigenic clays are found in different areas of the oceans in the east china sea the total amount of authigenic clays present must constitute a very minor fraction of the bottom sediments thus the formation of these minerals has a relatively small impact upon dissolved si distributions clay mineral reconstitution in nearshore regions may provide a mechanism for buffering sediments and overlying waters with respect to ph as the composition of minerals formed should be a direct function of the h activity in the surrounding environment

upper stratospheric circulations in the two hemispheres observed by satellites a global analysis is made of upper stratospheric circulations with the aid of nimbus 5 and tiros n satellite observations in order to make a comparison of characteristics between the northern hemisphere nh and the southern hemisphere sh it is shown that the reversal of north south gradient of the zonal mean temperature at the stratopause level is always observed in higher latitudes of the sh winter while the temperature gradient of the nh winter is variable because of the occurrence of sudden warmings consequently due to the thermal wind relation the polar night westerlies of the sh stratosphere are generally stronger than those of the nh stratosphere in association with this difference the activity of transient planetary waves of wavenumber 2 is striking in the sh in contrast to the predominance of steady waves in the nh finally the interrelation between the zonal mean field and planetary waves in the upper stratosphere is briefly discussed

contraction of the 300 mbar north circumpolar vortex during 1963 1997 and its movement into the eastern hemisphere the size of the 300 mbar north circumpolar vortex and its partition into western and eastern hemispheres and quadrants 0 90 w 90 w 180 90 e 180 and 0 90 is estimated by planimetering the area poleward of contours in the main belt of westerlies on the polar stereographic mean monthly analyses of the institute of meteorology of the free university of berlin during 1963 1997 the trend in annual vortex size is a significant 1 4 decade vortex contraction but with the trend in the western hemisphere portion of the vortex a significant 2 1 decade compared to 0 7 decade in the eastern hemisphere portion signifying a movement of the vortex farther into the eastern hemisphere thus while on average 52 of the vortex was in the eastern hemisphere during 1963 1997 this value increased by a significant 0 4 decade during the period resulting in a substantial increase in vortex eccentricity in winter and spring the vortex has moved mainly into the asian quadrant 90 e 180 whereas in summer the vortex has become elliptical with less of a decrease in size of quadrants 90 e 180 and 0 90 w and in autumn there has been a decrease in size of quadrant 90 w 180 relative to the other quadrants the standard deviation of the annual quadrant size anomalies has decreased significantly during 1963 1997 indicating a decrease in the annual displacements of the vortex center from its mean location as the eccentricity increases and the vortex contracts on the basis of a 41 station northern hemisphere radiosonde network during 1963 1997 the annual 850 300 mbar temperature increased by a significant 0 12 c decade in the northern hemisphere as a whole and by a significant 0 17 c decade in the western half and by 0 06 c decade in the eastern half of the hemisphere the resulting association of a 1 decade decrease in 300 mbar vortex size with about an 0 1 c decade increase in 850 300 mbar temperature differs by a factor of 2 from what would be expected hydrostatically a difference that would be eliminated by an 0 4 mbar decade increase in midlatitude surface pressure during 1963 1997

dynamics and geometry of extratropical cyclones in the upper troposphere by a neighbor enclosed area tracking algorithm abstractthis study shows that the morphological characteristics of upper tropospheric extratropical eddies are closely related to the background flow in the northern hemisphere winter enclosed surfaces of 300 hpa relative vorticity are identified by using the neighbor enclosed area tracking algorithm and the periphery of these surfaces are approximated by ellipses eddies are classified into five categories according to the approximate ellipse eddies having an oblateness of less than 0 6 are classified as near circle or are otherwise classified as northeast southwest ne sw northwest southeast nw se north south or west east according to the direction of the major axis in the wintertime climatology ne sw oriented cyclones are collocated with the jet stream while nw se oriented cyclones mostly reside north of the jet in interannual variability moreover the frequency of ne sw cyclones is slightly correlated with the arctic oscillation ao index while the frequency of nw se cyclones is high

the potential source of dissolved aluminum from resuspended sediments to the north atlantic deep water abstract laboratory and field studies were conducted to investigate the significance of resuspended sediments as a source of dissolved al to the deep northwest atlantic sediment resuspension experiments demonstrate the effect on dissolved al concentration initially 11 nm of adding natural suspended sediments ca 0 1 10 mg l to seawater the concentration of dissolved al increased by the resuspension of sediments for example addition of 0 15 mg l sediments caused dissolved al to increase by 10 nm distributions of dissolved and leachable particulate al off the tail of the grand banks near the highenergy western boundary current show elevated levels in the near bottom waters we suggest that resuspended sediments associated with nepheloid layers along the western boundary of the north atlantic are a source of dissolved al strong western boundary currents provide the energy to resuspend and maintain intense nepheloid layers of sediments continued resuspension and deposition of sediments within the nepheloid layer promotes the release of al from sediments to the overlying water the al rich terrigenous sediments that predominate along the deep boundary of the denmark strait labrador sea newfoundland and off nova scotia constitute a potentially significant source of dissolved al release of al from resuspended sediments associated with nepheloid layers at a more northern location e g denmark strait may contribute to the near linear increase in dissolved al with depth observed in the deep northwest atlantic

iron enrichments and fe isotopic compositions of surface sediments from the gotland deep baltic sea recent sediments from the gotland deep display enrichments in reactive fe associated with elevated fe al ratios and light fe isotopic signatures of the bulk sediments that are indicative of euxinic anoxic and sulfidic conditions these enrichments can be explained by the fe shuttle model where benthic fe is transported from the shelf to the euxinic basin and transferred to the sediments by pyrite precipitation in the sulfidic water the data provide evidence that the fe shuttle at present results in accumulations of fe that are larger compared to fe enrichments during the litorina sea stage in the gotland deep probably caused by an increase of the benthic fe flux from the shelf to the basin the derived fe enrichments are also larger compared to those in recent black sea sediments which likely reflects the larger shelf to basin ratio of the gotland deep compare to the black sea the fe isotope data show no correlation with the organic c content of the samples indicating that the negative fe isotope signatures are not associated with organic materials as was suggested as an alternative explanation for the origin of the isotopically light fe in sediments from the litorina sea stage conversely pyrites carry the negative fe isotopic signature of the sediments which supports the fe shuttle model variations in the abundance and fe isotopic signature of reactive fe and pyrite with depth suggest that syngenetically formed pyrite in the sulfidic water column has a less negative fe isotopic composition compared to diagenetically produced pyrite

dissolved aluminum in four chinese estuaries evidence of biogeochemical uncoupling of al with nutrients abstract four chinese estuaries the jiaojiang luanhe shuangtaizihe and yalujiang were investigated to determine al geochemistry and inter relations between al and nutrients these estuaries are characterised by low particulate organic carbon and high turbidity with various tidal regimes dissolved al was determined by fluorescence method after liquid liquid extraction into n hexanol concentrations of al in the luanhe estuary are relatively high 1 5 2 0 m and approximately uniform over the salinity range sampled suggesting the influence of in situ sources processes in the shuangtaizihe estuary riverine concentrations of al 1 8 2 2 m decrease with higher chlorinity indicating the predominance of simple dilution by seawater the jiaojiang and yalujiang provide evidence that al is removed from water column at early stages of estuarine mixing owing to probably the particle solution reactions e g flocculation in the estuary the al data are further compared with total suspended matter and nutrients in these estuaries the data sets indicate that aluminum is not dominantly coupled to the cycle of nutrients

cadmium isotope fractionation in seawater a signature of biological activity investigations of cadmium isotope variations in the oceans may provide new insights into the factors that control the marine distribution and cycling of this element here we present the results of cd isotope and concentration analyses for 22 seawater samples from the atlantic southern pacific and arctic oceans the results reveal for the first time large and well resolved cd isotope fractionations in the marine environment the majority of the seawater samples display an inverse relationship between dissolved cd contents and isotope compositions which range from e114 110cd 3 0 5 for cd rich waters 0 8 1 0 nmol kg to e114 110cd 38 6 for surface water with a cd concentration of only 0 003 nmol kg all e114 110cd data are reported relative to the jmc cd munster standard this suggests that the cd isotope variations reflect kinetic isotope effects that are generated during closed system uptake of dissolved seawater cd by phytoplankton a few samples do not follow this trend as they exhibit extremely low cd contents 0 008 nmol kg and nearly un fractionated cd isotope compositions such complexities which are not revealed by concentration data alone require that the cd distribution at the respective sites was affected by additional processes such as water mass mixing atmospheric inputs of cd and or adsorption uniform isotope compositions of e114 110cd 3 3 0 5 1 s d were determined for seawater from 900 m depth despite of cd concentrations that display the expected increase along the global deep water pathway from the atlantic 0 3 nmol kg to the pacific ocean 0 9 nmol kg this indicates that the biomass which is remineralized in the deeper ocean is also characterized by a very constant cd isotope composition this observation is in accord with the interpretation that the cd distribution in surface waters is primarily governed by rayleigh fractionation during near quantitative uptake of dissolved seawater cd

eastward travelling waves in the southern hemisphere stratosphere during the spring of 1983 this paper presents a case study of planetary waves in the southern hemisphere stratosphere during the spring of 1983 using the global temperature and geopotential height data provided by the united states national meteorological center nmc the eastward travelling wave of zonal wavenumber 2 with a period of 9 2 days persisted from mid september to early november it had a phase structure which showed only slight tilt with height and latitude while the quasi stationary wave 1 tilted westwards with increasing height and towards the equator during the vigorous period of the eastward travelling wave 2 the amplitude of the quasi stationary wave 1 varied with a period of about 10 days this variation was due to a coincidence between the phases of the stationary wave 1 and the eastward travelling wave 2 when the ridges of waves 1 and 2 overlap wave 1 amplitude reaches its maximum the active period of the travelling wave 2 is closely related to the seasonal change in the mean zonal winds in 1983 the eastward travelling wave 2 became vigorous after the zonal mean westerly jet moved rapidly poleward and downward compared with the other 5 years for which we have data the wind structure for the month of september 1983 was peculiar because of the stronger meridional curvature of the westerly jet

do split and displacement sudden stratospheric warmings have different annular mode signatures sudden stratospheric warmings ssws contribute to intraseasonal tropospheric forecasting skill due to their surface impacts recent studies suggest these impacts depend upon whether the polar vortex splits or is displaced during the ssw we analyse the annular mode signatures of ssws in a 1000 year ipsl cm5a lr simulation although small differences in the mean surface northern annular mode nam index following splits and displacements are found the sign is not consistent for two independent ssw algorithms and over 50 events are required to distinguish the responses we use the winter time correlation between extratropical lower stratospheric wind anomalies and the surface nam index as a metric for two way stratosphere troposphere coupling and find that the differences between splits and displacements and between classification methodologies can be simply understood in terms of their mean stratospheric wind anomalies predictability studies should therefore focus on understanding the factors that determine the persistence of these anomalies following ssws

the behavior of wave 2 in the southern hemisphere stratosphere during late winter and early spring abstract a detailed analysis is presented of the behavior of the zonal wavenumber 2 component of the flow wave 2 for july through october in the southern hemisphere stratosphere wave 2 in the stratosphere is characterized by a broad meridional structure peaking between 55 and 65 s and regular eastward propagation with periods ranging from 5 to 40 days maximum geopotential height amplitudes for a year range from approximately 600 to 1000 m examination of vertical structure suggests that during episodes of largest growth wave 2 propagates upward from the upper troposphere regular eastward propagation is however evident only within the stratosphere there are also episodes of wave 2 growth that do not appear connected with the troposphere in general the wave 2 amplitude is not as large in these cases there are several years when wave 1 and wave 2 amplitudes are strongly anticorrelated in time during september and october there are also years with strong positive correlation during august and

the coagulation of dissolved239 240pu in estuaries as determined from a mixing experiment a mixing experiment using large volumes 100 l of filtered 1 m freshwater and seawater end members was performed to simulate and investigate the chemical reactivity of239 240pu during estuarine mixing an organic rich freshwater with a relatively high concentration 0 8 dpm 100 l of dissolved239 240pu was used as one end member buzzards bay seawater dissolved239 240pu 0 04dpm 100l was the other the results demonstrate that dissolved239 240pu in the freshwater undergoes extensive and rapid coagulation under simulated estuarine conditions there is a strong correlation between the amount of coagulation of dissolved239 240pu humic acids ha and fe the extent of coagulation of all three constituents increases with increasing salinity and the net extent of their removal is 53 57 and 100 for pu ha and fe respectively as has been documented for fe in freshwater dissolved239 240pu appears to be stabilized by naturally occurring humic substances to form negatively charged colloids which are then coagulated by seawater cations the extrapolation of these experimental results to real estuaries will require additional research

synoptic dynamic climatology of the aleutian high abstracta climatology of the anticyclone that commonly appears over the aleutian islands in the wintertime northern hemisphere stratosphere is presented applying a geometric moments technique to a reanalysis dataset and updating a previously published definition 68 aleutian high ah events have been identified during 35 winter october march seasons 1979 80 2013 14 or about 2 events per season the events lasted an average of approximately 33 days thirteen of the 68 ah events each temporally and spatially coincided with tropospheric blocking identified with a wave breaking definition while 41 of the ah onsets each coincided with a persistently positive geopotential height anomaly in the troposphere also 41 of the 68 ah events each coincided with or were followed by an objectively defined disturbance split or displacement to the stratospheric polar vortex finally 47 of these disturbance events were each preceded by an ah onset such that in almost all winters 33 out of 35 an early season

polar vortices on earth and mars a comparative study of the climatology and variability from reanalyses polar vortices on mars provide case studies to aid understanding of geophysical vortex dynamics and may help to resolve long standing issues regarding polar vortices on earth due to the recent development of the first publicly available martian reanalysis dataset macda for the first time we are able to characterise thoroughly the structure and evolution of the martian polar vortices and hence perform a systematic comparison with the polar vortices on earth the winter atmospheric circulations of the two planets are compared with a specific focus on the structure and evolution of the polar vortices the martian residual meridional overturning circulation is found to be very similar to the stratospheric residual circulation on earth during winter while on earth this residual circulation is very different from the eulerian circulation on mars it is found to be very similar unlike on earth it is found that the martian polar vortices are annular and that the northern hemisphere vortex is far stronger than its southern counterpart while winter hemisphere differences in vortex strength are also reported on earth the contrast is not as large distinctions between the two planets are also apparent in terms of the climatological vertical structure of the vortices in that the martian polar vortices are observed to decrease in size at higher altitudes whereas on earth the opposite is observed finally it is found that the martian vortices are less variable through the winter than on earth especially in terms of the vortex geometry during one particular major regional dust storm on mars martian year 26 an equatorward displacement of the vortex is observed sharing some qualitative characteristics of sudden stratospheric warmings on earth

a chemical indicator of trade wind reversal in corals from the western tropical pacific historical levels of manganese have been measured in the annual rings of a reef coral from tarawa atoll 1 30 n 173 e in order to assess the temporal variability of this trace element in surface waters of the western tropical pacific seasonal variability associated with vertical mixing is not apparent as is the case in the eastern pacific however mn ca ratios are highly perturbed during three el nino southern oscillation enso events 1965 1972 1976 that occurred within the growth period 1960 1977 for approximately 6 months during each of these events mn ca ratios increase by 50 80 from a background of 27 nmol mn mol ca these features co occur with negative 18o pulses recorded in the same coral which result from anomalously abundant rainfall wet deposition of mn however does not appear to be an adequate source to account for the inferred surface ocean enrichments the most plausible explanation has to do with the transient appearance of westerly winds along the equator during enso periods particularly vigorous westerly wind bursts sometimes averaging 10 m sec or more over 16 hours during the aforementioned years may have generated wind waves of sufficient strength to create an aura of particulate and diagenetically remobilized mn from within the shallow westward facing lagoon of tarawa this interpretation is supported by relatively high mn concentrations measured in pore waters of tarawa lagoon sediments the results suggest a useful new chemical tracer of historical enso conditions in the western pacific basin

a mid twentieth century reduction in tropical upwelling inferred from coralline trace element proxies abstract the cariaco basin is an important archive of past climate variability given its response to inter and extratropical climate forcing and the accumulation of annually laminated sediments within an anoxic water column this study presents high resolution surface coral trace element records montastrea annularis and siderastrea siderea from isla tortuga venezuela located within the upwelling center of this region a two fold reduction in cd ca ratios 3 5 1 7 nmol mol is observed from 1946 to 1952 with no concurrent shift in ba ca ratios this reduction agrees with the hydrographic distribution of dissolved cadmium and barium and their expected response to upwelling significant anthropogenic variability is also observed from pb ca analysis observing three lead maxima since 1920 kinetic control of trace element ratios is inferred from an interspecies comparison of cd ca and ba ca ratios consistent with the sr ca kinetic artifact but these artifacts are smaller than the environmental signal and do not explain the cd ca transition the trace element records agree with historical climate data and differ from sedimentary faunal abundance records suggesting a linear response to north atlantic extratropical forcing cannot account for the observed historical variability in this region

porewater cadmium geochemistry and the porewater cadmium δ13c relationship results from two continental margin cores collected off pt sur california make possible a direct determination of the relationship between dissolved cadmium and the carbon isotopic composition of dissolved inorganic carbon in the interstitial water of suboxic marine sediments the 13c values of dissolved inorganic carbon decrease nearly 1 in the top 0 5 cm of the sediments and display a more gradual decrease through the top 20 cm of the sediments dissolved cadmium concentrations increase by 0 6 to 1 5 nmol kg in the top 0 5 cm of the sediments and then rapidly decrease to values of approximately 0 12 nmol kg between 5 and 10 cm into the sediments apparently as a result of scavenging onto iron oxide surfaces this pattern contrasts with porewater cadmium profiles previously reported for pelagic sediments which show no evidence of cadmium scavenging by the sediments however porewater cadmium concentrations are poorly correlated with porewater 13c values in both oxic and suboxic sediments these results suggest that the cadmiumcalcium ratios and 13c values of infaunal benthic foraminifera need not be tightly linked and that the relationship between these two aspects of foraminiferal shell chemistry may vary in response to changes in sediment geochemistry

dissolved aluminium in the tamar estuary southwest england abstract distributions of dissolved al in the tamar estuary have been recorded through spring neap tidal cycles in winter and summer dissolved al is a highly reactive constituent in this estuary undergoing net removal in the very low salinity region and net input to the mid estuary the extent of both the depletion and the augmentation varied systematically with tidal energy input indicating that tidal sediment disturbance was the principal controlling agency these field data supported by the results of laboratory simulations show that the removal is regulated by sorption onto resuspended sediment particles which dominates kinetically over authigenic aluminosilicate formation removal of dissolved al by flocculation of riverborne colloids is not significant the mid estuarine input is consistent with dissolution of authigenic aluminosilicate following net remobilization of estuarine sediment the internal cycling of al in the estuary generated by these processes alters both the time course and the soluble particulate balance of the riverine discharge of al to the adjacent coastal water

dissolved aluminium in the mediterranean abstract three vertical profiles of dissolved al and nutrients are reported from the eastern basin of the mediterranean profiles of al concentrations resemble those of the nutrient elements except that a proportionally higher residual concentration remains in the surface layer concentrations of al in the surface water inflow from the north atlantic which contains between 10 and 20 nm around gibraltar are elevated to 55 59 and 75 nm at the stations occupied calculations indicate that these concentrations are probably produced by dissolution al from aeolian dust and advective mixing of al rich deep waters into the surface layer balanced by a biologically associated removal process the al removed from the surface layer redissolves in the deep water to raise al concentrations to about 160 nm samples were also recovered from anoxic deep brines in the tyro and bannock basins in the brines al concentrations fall to about 15 nm while si concentrations approach 270 nm

distribution of aluminium in waters of the north east atlantic 25 n to 35 n abstract dissolved al concentrations from the ne atlantic between 25 n and 35 n off the coast of nw africa range from 16 nm to 32 nm in a well mixed surface layer extending to 150 m depth increasing towards the maximum of the saharan dust plume mediterranean outflow water is detected as a high al anomaly corresponding to the salinity signal of the mediterranean water other than in surface and mediterranean waters al concentrations are invariant with depth but increase from 6 nm to 11 nm towards the continental margin the magnitude of the dissolved al signal in the surface layer is compatible with dissolution of al from the highest of present estimates of dust input to this area comparison with data from other areas indicates that al cannot be cycled through the oceans in parallel to silica as has been previously suggested

relation of size and displacement of the 300 mbar north circumpolar vortex to qbo el nino and sunspot number 1963 2000 the size of the 300 mbar north circumpolar vortex and its eastern western date line and greenwich hemisphere components is estimated for the period 1963 2000 by planimetering the area poleward of 300 mbar contours in the main belt of westerlies on the mean monthly polar stereographic analyses of the institute of meteorology of the free university of berlin on the basis of the superposed epoch method there is little evidence of a relation between vortex size and phase of the qbo but significant at the 90 level or better is the tendency for the vortex to be less displaced into the eastern hemisphere in the east wind phase of the qbo for the vortex to be expanded near the time of nino 3 sea surface temperature maximum el nino but contracted 3 4 seasons after and for the vortex to be displaced farther into the date line hemisphere when there is an el nino there is also an impressive tendency for the winter vortex to be less displaced into the eastern hemisphere at the time of el nino the tendency for the vortex to be contracted near sunspot maximum and expanded near sunspot minimum is significant at only about the 80 level because of the small sample size

the distribution of dissolved and total dissolvable aluminum in the beaufort sea and canada basin region of the arctic ocean 1 vertical profiles of the concentrations of dissolved al d al and total dissolvable al t al are reported from a transect extending from the continental shelf of the beaufort sea into the canada basin in the arctic ocean sampling was performed in late summer and early autumn 2007 a year of historically extensive sea ice melt vertical profiles of d al displayed surface maxima 1 3 nmol kg 1 subsurface minima 300 m depth suggest that al is likely lost through particle scavenging in the interior of the canada basin concentrations of t al show that particulate al 0 2 m is the dominant form of al in the water column except at greater depths at the most offshore stations lateral transport of d al and t al off the shelf likely results from the offshore progression of cyclonic eddies spawned inshore oscillating upwelling and downwelling favorable winds and brine rejection during sea ice formation that can drive currents sufficiently energetic to resuspend shelf sediments

on the distribution of copper nickel and cadmium in the surface waters of the north atlantic and north pacific ocean concentrations of copper nickel and cadmium have been determined for about 250 surface water samples nonupwelling open ocean concentrations of these metals are cu 0 5 1 4 nmol kg ni 1 2 nmol kg and cd less than 10 pmol kg in the equatorial pacific upwelling zone concentrations of ni 3 nmol kg and cd 80 pmol kg are higher than in the open ocean but cu 0 9 nmol kg is not significantly enriched metal concentrations are higher in cool nutrient rich eastern boundary currents cu 1 5 nmol kg ni 3 5 nmol kg and cd 30 50 pmol kg copper is distinctly higher in the coastal waters of the gulf of panama 3 4 nmol kg and also higher in the shelf waters north of the gulf stream 2 5 nmol kg these copper enrichments may be caused by copper remobilized from mildly reducing shelf sediments and maintained by a coastal nutrient trap in the open ocean events of high cu water 1 5 3 5 nmol kg are seen on scales up to 60 km presumably these are due to the advection of coastal water into the oceanic interior the lowest copper concentrations in the north pacific central gyre 0 5 nmol kg bruland 1980 are lower than in the sargasso sea 1 3 nmol kg while for nickel the lowest concentrations are 2 nmol kg in both the north pacific and the north atlantic nickel and cadmium while generally correlated with the nutrients in surface waters show distinct regional changes in their element nutrient correlations the residual concentrations of trace metals in the surface waters of the ocean can be explained if biological discrimination against trace metals relative to phosphorus increases as productivity decreases

subarctic wintertime dissolved iron speciation driven by thermal constraints on fe ii oxidation dissolved organic matter and stream reach abstract we studied the seasonal variations in fe ii fe iii humic like dissolved organic matter dom nitrate and nitrite no 3 no 2 and silicate si oh 4 in river waters of three subarctic rivers flowing into hakodate bay in southwestern hokkaido japan from may 2010 to february 2014 high fe ii concentrations were detected in winter at the sampling sites where the river bottom was comprised of sandy or silty sediment primarily the lower and middle reaches of the rivers conversely from early spring to late autumn fe ii levels were low or undetectable we infer that soluble fe ii concentration in these subarctic river waters is driven by the balance between the influx of fe ii to the river and the fe ii oxidation rates that determines the dynamics in fe ii concentration in the river water the fe ii may originate from reductive dissolution of fe iii in the river sediment or from fe ii bearing groundwater the latter seems to be the most likely source during winter time the high fe ii concentrations during winter is predominantly attributed to the extremely slow oxidation rate of fe ii to fe iii at low water temperature rather than to an actual increase in the flux of reduced fe ii nevertheless we propose that the flux of reduced fe ii from river sediments and groundwater in lowland area of the catchment to overlying river waters might be the most important sources of iron in river waters this provides an important insight into the role of river processes and the interaction between climate and river morphology in determining the inputs of iron to subarctic coastal marine waters

large scale patterns of auroral ionospheric convection observed with the chatanika radar ionospheric convection at auroral latitudes has been examined during a series of long duration experiments with the chatanika alaska incoherent scatter radar these experiments have been carefully designed to obtain maximum latitudinal coverage 56 75 while maintaining a temporal resolution of 30 min in order to resolve the effects of individual substorms on the convection pattern design criteria for the experiments are described together with presentation of observational data acquired during 400 hr of radar operations during various levels of geophysical disturbance the data accentuate the repeatability of the gross features of the auroral convection and its basic conformity to the two cell pattern predicted from the large scale magnetospheric circulation for moderate to active geomagnetic conditions uniform sunward convection with velocities of 800 1200 m s spans the 62 to 72 latitude band at both dawn and dusk in quieter circumstances the sunward convection continues in this region but has smaller speeds and is centered at higher latitudes little evidence of a throat in the dayside convection pattern is seen at latitudes below 75 except in very disturbed circumstances during several experiments coordinated operation of the chatanika and millstone hill massachusetts radars permitted the simultaneous observation of the auroral convection pattern at two different local times substorms affect the convection at all local times and appear to generally enhance the rate of convection without seriously changing its direction near midnight latitudinal displacements and expansions of the convection pattern during substorms may result in a local rotation or reversal of the direction of convection while near dawn and dusk convection velocities are enhanced and the region of sunward flow expands to lower latitudes

cadmium in the north atlantic implication for global cadmium phosphorus relationship abstract dissolved cadmium cd distribution was determined in the tropical subtropical north atlantic along geotraces ga03 section us geotraces 2010 and 2011 cruises a pronounced mid depth cd maximum extends from the productive tropical eastern north atlantic where subsurface waters in the upper themocline are depleted in dissolved oxygen at this cd maximum cd depletion relative to phosphate po4 is observed in the cd vs po4 plot but the relative cd depletion is not present in the plot of cd po4 ratio vs depth the apparent relative cd depletion at the cd maximum appears to reflect a depth dependent variation of cd po4 ratio commonly observed in the world ocean such depth dependent variation of cd po4 ratio may result from the regeneration of cd from cd poor particulate organic carbon poc in the upper ocean and from cd rich poc in the deep ocean the vertical cd regeneration may lead to the observed difference in deep water cd po4 ratio between the north atlantic and north pacific if cd to phosphorus ratio in the poc flux to the deep ocean is higher in the pacific than in the atlantic

awesome ocim a simple flexible and powerful tool for modeling elemental cycling in the oceans abstract here we present a new flexible modeling tool for simulating the distribution of tracers in the modern ocean a working environment for simulating ocean movement and elemental cycling within an ocean circulation inverse model the awesome ocim is a transport matrix model tmm which is specifically designed to be easy accessible and intuitive even for scientists without prior modeling experience the awesome ocim comes with a variety of selectable biogeochemical functions including sources atmospheric dust hydrothermal vents and seafloor nepheloid layers internal cycling processes biological uptake remineralization and scavenging and sinks radioactive decay and burial of particles in the sediments a wide variety of elements can be simulated through different combinations of this suite of processes we anticipate that the awesome ocim will be a valuable tool for interpreting transect data from ocean surveys particularly the trace elements and isotopes distributions mapped by the ongoing geotraces program this manuscript provides an introduction to the philosophical mathematical and functional basis of the awesome ocim

a new look at stratospheric sudden warmings part iii polar vortex evolution and vertical structure the evolution of the arctic polar vortex during observed major midwinter stratospheric sudden warmings ssws is investigated for the period 1957 2002 using 40 yr european centre for medium range weather forecasts ecmwf re analysis era 40 ertel s potential vorticity pv and temperature fields timelag composites of vertically weighted pv calculated relative to the ssw onset time are derived for both vortex displacement ssws and vortex splitting ssws by averaging over the 15 recorded displacement and 13 splitting events the evolving vertical structure of the polar vortex during a typical ssw of each type is clearly illustrated by plotting an isosurface of the composite pv field and is shown to be very close to that observed during representative individual events results are verified by comparison with an elliptical diagnostic vortex moment technique for both types of ssw little variation is found between individual events in the orientation of the developing vortex relative to the underlying topography that is the location of the vortex during ssws of each type is largely fixed in relation to the earth s surface during each type of ssw the vortex is found to have a distinctive vertical structure vortex splitting events are typically barotropic with the vortex split occurring near simultaneously over a large altitude range 20 40 km in the majority of cases of the two daughter vortices formed it is the siberian vortex that dominates over its canadian counterpart in contrast displacement events are characterized by a very clear baroclinic structure the vortex tilts significantly westward with height so that the top and bottom of the vortex are separated by nearly 1808 longitude before the upper vortex is sheared away and destroyed

climatology of arctic and antarctic polar vortices using elliptical diagnostics abstract the climatological structure and interannual variability of the arctic and antarctic stratospheric polar vortices are examined by analysis of elliptical diagnostics applied to over 19 yr of potential vorticity data the elliptical diagnostics define the area center elongation and orientation of each vortex and are used to quantify their structure and evolution the diagnostics offer a novel view of the well known differences in the climatological structure of the polar vortices although both vortices form in autumn to early winter the arctic vortex has a shorter life span and breaks down over a month before the antarctic vortex there are substantial differences in the distortion of the vortices from zonal symmetry the arctic vortex is displaced farther off the pole and is more elongated than the antarctic vortex while there is a midwinter minimum in the distortion of the antarctic vortex the distortion of the arctic vortex increases during its life cycle there are also large differenc

the influence of stratospheric vortex displacements and splits on surface climate abstracta strong link exists between stratospheric variability and anomalous weather patterns at the earth s surface specifically during extreme variability of the arctic polar vortex termed a weak vortex event anomalies can descend from the upper stratosphere to the surface on time scales of weeks subsequently the outbreak of cold air events have been noted in high northern latitudes as well as a quadrupole pattern in surface temperature over the atlantic and western european sectors but it is currently not understood why certain events descend to the surface while others do not this study compares a new classification technique of weak vortex events based on the distribution of potential vorticity with that of an existing technique and demonstrates that the subdivision of such events into vortex displacements and vortex splits has important implications for tropospheric weather patterns on weekly to monthly time scales using reanalysis data it is found that vortex splitting events are correl

first data on trace metal level and behaviour in two major arctic river estuarine systems ob and yenisey and in the adjacent kara sea russia dissolved and colloidal trace element concentrations cd cu fe ni and pb were determined in the ob and yenisey river estuary systems and in the adjacent kara sea in september 1993 the data show a natural low concentration level of dissolved 0 4 m trace metals cd cu fe ni and pb in the two rivers and in the kara sea as compared to world unpolluted rivers and the central arctic ocean suggesting that the region studied is pristine with respect to trace metals the pathway of trace metals transported from rivers to the ocean seems to be complicated and largely influenced by biogeochemical processes taking place in the estuarine mixing zone colloidal material 104 daltons 0 4 m in addition to its significant contribution to the so called dissolved fraction has been shown to play a fundamental role in determining the behaviour of both conservative and non conservative trace metals during estuarine mixing hence colloids may control to a large extent the fate of dissolved trace metals as well as their net input from the rivers to the kara sea

the structure of the polar vortex reconstruction of the airborne antarctic ozone experiment and airborne arctic stratosphere expedition aircraft constituent observations radiative heating rate computations and trajectory calculations are used to generate comparative pictures of the 1987 southern hemisphere sh late winter and 1989 northern hemisphere nh mid winter lower stratospheric polar vortices overall both polar vortices define a region of highly isolated air where the exchange of trace gases occurs principally at the vortex edge through erosional wave activity aircraft measurement showed that 1 between 50 and 100 mbar horizontally stratified long lived tracers such as n20 are displaced downward 2 3 km on the cyclonic poleward side of the jet with the meridional tracer gradient sharpest at the jet core 2 eddy mixing rates computed using parcel ensemble statistics are an order of magnitude or more lower on the cyclonic side of the jet compared to those on the anticyclonic side 3 poleward zonal mean meridional flow on the anticyclonic side of the jet terminates in a descent zone at the jet core despite the similarities between the sh and nh winter vortices there are important differences during the aircraft campaign periods the sh vortex jet core was located roughly 8 o 10 o equatorward of its nh counterpart after pole centering as a result of the arger size of the sh vortex the dynamical heating associated with the jet core descent zone is displaced further from the pole the sh polar vortex can therefore approach radiative equilibrium temperatures over a comparatively larger area than the nh vortex the subsequent widespread formation of polar stratospheric clouds within the much colder sh vortex core gives rise to the interhemispheric differences in the reconstructed h20 noy c10 and 03 species which are affected by polar stratospheric clouds

a model for interpreting continental shelf hydrographic processes from the stable isotope and cadmium calcium profiles of scallop shells abstract stable oxygen and carbon isotope and cadmium calcium profiles from the shells of scallops collected from the outer continental shelf of the south atlantic bight and the virginia bight appear to trace the hydrographic processes of the two regions a model is developed to distinguish two principal modes of nutrient and trace metal input to the outer shelf from the biogeochemical profiles of the shell the oxygen isotope profiles record bottom water temperature changes caused by seasonal temperature cycles and water mass movements nutrient input and subsequent phytoplankton blooms are recorded in the carbon isotope and cd ca profiles the shell profiles from the south atlantic bight record the dominant effect of upwelling caused by gulf stream meandering the shell profiles from the virginia bight show the influence of spring river runoff and summer water column stratification biogeochemical profiles in mollusk shells are potentially important tools for studying the dynamics of both modern and ancient continental shelf upwelling systems

heavy nickel isotope compositions in rivers and the oceans abstract nickel is a biologically active trace metal whose dissolved concentration depth profiles in the ocean show nutrient like behaviour if the pronounced removal of nickel from the dissolved phase in the surface ocean and its return in the deep is associated with an isotopic fractionation nickel isotopes may be able to yield constraints on the precise biogeochemical processes involved here we present the first nickel isotope data for seawater along with data for the dissolved phase of rivers one of the principal sources of nickel to the oceans the dissolved phase of rivers exhibits substantial variability in both ni concentration and 60 ni from 2 2 to 35 nmol kg 1 and 0 29 to 1 34 respectively the most striking result from the nickel isotope analyses of rivers is that they are substantially heavier by up to 1 for 60 ni than the range for silicate rocks on the continents a finding that is analogous to that for other transition metal isotope systems if the data presented here are close to representative of the global riverine flux they suggest an annual input of ni to the oceans of 3 6 10 8 moles and a discharge and concentration weighted 60 ni average of 0 80 the relationship between ni isotopes and concentrations shows similarities with those for other transition metal isotope systems where the main control has been suggested to be isotopic partitioning between the dissolved phase and particulates either in the weathering environment or during transport in stark contrast to the rivers the dataset for seawater is very homogeneous with 2sd of the entire dataset being only twice the analytical reproducibility the second main feature is that seawater is distinctly heavier in ni isotopes than rivers the average 60 ni is 1 44 0 15 2sd and only 2 of the 29 seawater analyses have a ni isotopic composition that is lighter than the heaviest river the lack of an isotopic shift associated with the drawdown of nickel concentrations in the surface ocean suggests that the cycling of nickel between the surface and deep ocean is not associated with a pronounced isotopic fractionation the isotopic data also present a mass balance problem the main output of nickel from the oceans sorption to fe mn oxides appears to be similar in isotopic composition to the dissolved phase yet the riverine input is lighter than the dissolved pool this observation either requires other inputs that are isotopically heavy or an output that is isotopically light further large inputs over and above the dissolved riverine source appear to be required by what we know of the elemental budget but the isotopic mass balance suggests that such an input needs to be isotopically much heavier than both the riverine dissolved load and the lithogenic isotopic composition of nickel

dissolved iron and macronutrient distributions in the southern california current system 1 the distribution of dissolved iron in the southern california current system sccs is presented from seven research cruises between 2002 and 2006 dissolved iron concentrations were generally low in most of the study area 0 5 nm although high mixed layer and water column dissolved iron concentrations up to 8 nm were found to be associated with coastal upwelling both along the continental margin and some island platforms a significant supply of iron was probably not from a deep remineralized source but rather from the continental shelf and bottom boundary layer as identified in previous studies along the central and northern california coast with distance offshore dissolved iron decreased more rapidly relative to nitrate in a transition zone 10 250 km offshore during spring and summer resulting in relatively high ratios of nitrate dissolved iron higher nitrate dissolved iron ratios could be the result of utilization and scavenging in addition to an overall lower supply of iron relative to nitrate in the offshore transition zones the low supply of iron leads to phytoplankton iron limitation and a depletion in silicic acid relative to nitrate in the coastal upwelling and transition zones of the sccs

a study of planetary waves in the southern winter troposphere and stratosphere part i wave structure and vertical propagation abstract planetary wave propagation in the southern winter troposphere and stratosphere is studied in an attempt to trace the origins of upward propagating disturbance daily geopotential girds from 1000 to 1 mb are analyzed for two 120 day winter seasons a cross correlation analysis technique is developed which allows coherent wave structure to be traced in time significant correlations are observed between the troposphere and stratosphere at finite time lags indicative of vertically propagating waves the observed vertical propagation time scales between the middle troposphere and middle stratosphere are on the order of 4 days for zonal wavenumber 1 k 1 1 2 days for k 2 and 1 day for k 3 the cross correlation analysis also delineates the meridional and vertical structures of the transient in time planetary waves zonal wavenumber 1 fluctuations exhibit a vertical out of phase relationship between the midlatitude troposphere and atmosphere three out of phase maxima in latitude are observed in

vertical profile of artificial radionuclide concentrations in the central arctic ocean abstract the artificial radionuclides 90 sr 137 cs 238 pu 239 240 pu and 241 am have been measured in eight water samples collected in 1979 at intervals from surface to bottom through the ice at the lorex satellite camp ss near the north pole differences in the concentrations and ratios of these nuclides compared with values measured over time in the various water masses that flow into the arctic ocean can be used as semi independent checks on rates of flow to the lorex stations and on residence times in the arctic ocean an unexpected finding was that water labelled with low level liquid waste from the windscale plant on the irish sea is a major component of the 1500 m lorex sample and has reached there in no more than eight to ten years even from this one station in the polar ocean estimation of the inventories of the various radionuclides is good enough to emphasize the importance of horizontal advection of the various supply terms to the arctic

changes in the 300 mb north circumpolar vortex 1963 2001 abstract the mean monthly polar stereographic map analyses of the free university of berlin terminated at the end of 2001 this paper summarizes the changes in size of the 300 mb north circumpolar vortex and quadrants for the full period of record 1963 2001 where the size has been defined by planimetering the area poleward of contours in the jet stream core a contracted vortex has tended to be a deep vortex in winter but a shallow vortex in summer during 1963 2001 there was a statistically significant decrease in vortex size of 1 5 per decade the decrease in size of western hemisphere quadrants being twice that of eastern hemisphere quadrants a significant increase in arctic oscillation ao index accompanies the significant decrease in vortex size but since the vortex contracts appreciably in all four seasons whereas the positive trend in the ao index is mainly in winter the vortex cannot serve as a proxy for the ao index the evidence for vortex contraction at the time of the 1976 77 regime

a new purification method for ni and cu stable isotopes in seawater provides evidence for widespread ni isotope fractionation by phytoplankton in the north pacific abstract nickel and copper are cofactors in key phytoplankton enzymes and the stable isotope composition of ni and cu 60ni and 65cu in seawater have the potential to identify major processes that influence their biogeochemistry however accurate analysis of 60ni and 65cu is challenging because of the difficulties in separating these metals from interfering elements in the seawater matrix here we report a fast and simple method for purification of ni and cu from seawater samples that is able to completely remove interfering elements mn ti cr and fe this method was verified by analyzing four reference materials that contain significant levels of interfering elements powdered plankton natural soils and two marine sediments using this technique we generated a dataset of 49 seawater 60ni and 65cu measurements from the upper water column of the north pacific ocean which show preferential uptake of light ni isotopes by phytoplankton bio sw 0 9997 1 but no net fractionation of cu isotopes this new method simplifies treatment of seawater samples for ni and cu isotope analysis enabling high throughput investigations of 60ni and 65cu throughout the global ocean

climatology of the stratospheric polar vortex and planetary wave breaking abstract we use the distribution of ertel s potential vorticity pv on the 850 k isentropic surface to establish a climatology for the transient evolution of the planetary scale circulation in the northern hemisphere winter midstratosphere we compute pv distribution from gridded nmc daily temperature and height maps for the 10 and 30 mb levels and show that a very good approximation for 850 k pv can be derived from 10 mb heights and temperatures alone we assume that reversals of the latitudinal gradient of pv localized in longitude and latitude may be regarded as signatures of planetary wave breaking wave breaking identified by such signatures tends to occur mainly in the vicinity of the aleutian anticyclone with a secondary maximum over europe the area of the polar vortex defined as the area enclosed by pv contours greater than a certain critical value is strongly influenced by wave breaking erosion of the polar vortex due to transport and mixing of pv leads to a preconditioned state when def

assessing the application of trace metals as paleoproxies and a chemostratigraphic tool in carbonate systems a case study from the mississippian limestone of the midcontinent united states abstract trace metals have been successfully used to reconstruct geochemical seawater conditions of both modern and ancient environments the majority of these efforts have been limited to marine shales with little work on carbonate systems applying similar methods of trace metal analysis on carbonate dominated rocks may provide valuable insight into the paleoseawater chemistry such as redox state and productivity of ancient carbonate systems this study evaluates the application of trace metals as paleoproxies in carbonate rocks middle ramp wackestones to grainstones from the mississippian limestone in the midcontinent were analyzed using inductively coupled plasma mass spectrometry icp ms for both the carbonate fraction and the bulk fraction trace metal content our data show that productivity proxies such as cd and p are captured within the carbonate fraction and may reflect seawater chemistry of the system high cd and moderate bionutrient p ni zn enrichments indicate primary productivity in the system though it is difficult to quantify to what extent vanadium cr u and mo appear to be primarily associated with the bulk fraction content and correlate well with al content indicating a detrital origin furthermore v u and mo show no significant enrichments and mo fe ratios correlate with those of shales from a modern oxic shelf this suggests that anoxic or euxinic conditions in the water column were not present trace metal content of carbonate rocks have the potential to be used in paleoenvironmental reconstruction of carbonate systems though challenges exist such as the lack of comparable carbonate trace metal data bias of trace metal incorporation pathways into carbonates and diagenetic alteration

trace metal enrichments in the mediterranean sea copper nickel and cadmium occur at higher concentrations in the surface waters of the mediterranean than in nutrient depleted waters of the open ocean trace metal profiles have been taken on both sides of the strait of gibraltar to constrain a mass balance deep mediterranean waters have trace metal levels comparable to surface waters in regions of mediterranean deep water formation implying a minimal role for vertical transport by biological activity excess trace metals are not present in open atlantic source waters but a detailed map of trace metal distributions in the alboran sea immediately east of the strait reveals a metal enriched plume with concentrations as high as copper 3 6 nmol kg nickel 2 8 nmol kg and cadmium 120 pmol kg a substantial enrichment in trace metal concentrations therefore can occur in transit from the open atlantic through the coastal zone into the strait this trace metal enrichment may derive either from river inflow masked by evaporation diffusion out of continental shelf sediments eolian particulate fallout or anthropogenic sources metal sources fluvial sedimentary or atmospheric natural or anthropogenic are difficult to discern from the large scale oceanographic distribution metal retention in nutrient depleted surface waters is not due to unusual metal fluxes relative to nutrients but instead is a consequence of less frequent recycling of nutrients in the mediterranean compared to the open ocean metal enrichments would be expected before human intervention with anthropogenic input reflected in proportion to the relative augmentation of inputs over natural levels mediterranean water produces small trace metal anomalies in the outflow core positive for ni negative for cd present observations are consistent with this prediction but high precision data would be necessary to observe these at distance from gibraltar

the geochemistry of manganese in the northeast pacific ocean off washington1 2 water collected along a transect normal to the coast of washington was analyzed for dissolved co 4 pm and total dissolvable manganese tdm the vertical profiles exhibit the same general features observed elsewhere in the pacific but a horizontal section of the transect shows that concentrations increase markedly toward the continental margin a surface maximum ranging from 0 57 nmol kg in offshore waters to 5 24 over the continental slope is probably due to fluvial inputs especially from the columbia river another possible source is the upwelling of manganeseenriched bottom water over the shelf horizontal gradients are also observed in the oxygen minimum as manganese concentrations decrease from 4 75 nmol kg l near the continental slope to 0 7 1 in open ocean water porewater and solid phase data suggest that manganese is being actively remobilized under reducing conditions in the slope sediments and is diffusing into the overlying seawater at a rate sufficient to balance losses by vertical mixing and particulate scavenging two stations on opposite sides of the juan de fuca ridge have deep concentration maxima that are almost certainly due to injections of hydrothermal vent fluid along the ridge

aluminium in the northwest atlantic abstract a series of profiles between woods hole and bermuda has been measured on board ship for al the extrema in the upper waters can be explained by the accumulation of aeolian inputs in the thin summer mixed layer the depletion of the underlying winter water by scavenging during the spring bloom and the enrichment of the subtropical mode 18 c water by aeolian accumulation during winter and local convection before the spring bloom the pronounced minimum at mid depth is associated with the antarctic intermediate water and the underlying labrador sea med water complex presumably the aaiw and the med water are depleted by the ageing effect on this short residence time element during their transit to the area the lsw is formed from surface waters containing a large component of arctic waters extremely depleted in al advected south in the east greenland current the linear increase to the bottom is caused by mixing of enriched lower north atlantic deep water with the depleted bottom water and lsw cores the enrichment in the deep water appears to be produced by the entrainment of high al waters from the north european shelf by the gyre in the norwegian greenland sea and its injection into the denmark straits overflow waters in a manner recently described for the radiocaesium releases from the windscale reprocessing plant on the irish sea an additional contribution probably comes from the shelf north of iceland

geochemical profiles in the central arctic ocean their relation to freezing and shallow circulation temperature salinity nutrient tritium and oxygen isotope data collected during the lomonosov ridge experiment along a drift track between the makarov and fram basins over the lomonosov ridge are presented the relationship of these quantities to the processes that maintain the halocline in particular to the production of more saline waters by addition of brines formed during the freezing of seawater is described the results support the idea that the wide continental shelves of the arctic ocean play an important role in maintaining the halocline productivity and to the chemical and physical effects of freezing sea water a comparison of this ocean with its low productivity at least during winter with other oceanic regions should help to elucidate some of the effects of biological activity on marine chemistry for example trace metal cycling and speciation aagaard et al 1981 discussed the way in which the cold waters of the halocline which lie immediately below the surface mixed layer and extend to the top of the warm atlantic layer could be produced on the wide continental margins surrounding the arctic ocean the processes in volve freezing with release of highly saline brines having a temperature close to the freezing point of surface sea water this water flows over the shelves and into the central basin sinking then to the appropriate density surface the distribu tions of various chemical parameters will be affected in predictable ways by these processes as a part of the lomonosov ridge experiment lorex which ran from late march until the end of may 1979 a program was undertaken aimed at describing more accurate ly the hydrography of the central arctic ocean and studying the geochemistry of selected trace elements in this unusual environment to this end water samples were collected from a drifting ice station lorex satellite camp 1 for the measurement of salinity silicate phosphate 5 80 trace metals moore 1981 1983 carbon 14 tritium helium 3 caesium 137 caesium 134 strontium 90 plutonium ameri cium h d livingston et al manuscript in preparation 1983 alkalinity and ph ice cores were collected to investi gate the possibility of deducing the extent of temporal changes in the tritium content of the surface waters

oceanographic distributions of zinc cadmium copper and aluminium in waters of the central arctic vertical profiles are presented of dissolved cadmium zinc copper and aluminium at the lorex 79 site in the central arctic ocean cd zn and cu show unusually high surface concentrations of 0 3 3 and 5 nmoll 1 respectively these levels are related to contributions from surface run off and from the underlying nutrient rich bering sea winter water al has lower surface concentrations than observed elsewhere and shows no correlation with the nutrients the importance of aeolian supply is questioned and the results point to a major role for inorganic removal of al at least in the arctic ocean

the distribution of nutrients in the southeastern beaufort sea implications for water circulation and primary production hydrographic data collected above the shelf and slope in the southeastern beaufort sea show marked contrast in surface properties of nutrients temperature salinity and oxygen between august 1974 a year when ice remained close to shore and august 1975 a year with much open water the near surface properties are dominated by river inputs biological activity and the ice regime below the winter mixed zone 40 50 m properties are similar to those observed elsewhere in the arctic ocean bering sea water is detected at 50 60 m as a very weak signal in temperature nutrients and oxygen upwelling in both years was observed at the eastern side of mackenzie canyon this upwelling likely results from the interaction of coastal circulation with topography estimates of new productivity based on nutrient budgets are low 20 g c m 2 yr 1 compared to temperate coastal waters but fall in the range expected for the arctic in 1974 the heavy ice year turbid water and ice cover appear to have reduced new production by about 30 calculations show that this production over the shelf could potentially supply a significant portion of the nutrients found in the upper halocline over a wide region of the arctic ocean by regeneration at the shelf bottom and transport off the shelf in brine drainage

the seasonal evolution of planetary waves in the southern hemisphere stratosphere and troposphere seasonality in planetary wave structure in the southern hemisphere stratosphere and troposphere 1000 1 mb is studied based on eight years 1979 1986 of daily geopotential data emphasis is placed on the distinctive seasonality in the stratosphere along with tracing the stratospheric fluctuations into the troposphere time filtering is used to separate stationary and transient components maximum geopotential height variance is observed in the middle to upper stratosphere in late winter spring with a distinct secondary smaller maximum in late fall early winter these maxima sandwich the strongest mid winter zonal winds this sequence occurs approximately one month earlier in the upper stratosphere two corresponding peaks are observed in stratospheric zonal mean wind and temperature fluctuations the two maxima in stratospheric wave variance are not in agreement with observed seasonal changes in quasi geostrophic refractive index of the zonal mean flow the stratospheric geopotential variance maxima result from nearly equal amounts of stationary and transient zonal wave 1 fluctuations with transient wave 2 also contributing during late winter stationary wave 1 shows intriguing seasonal evolution the early winter maximum is predominantly equivalent barotropic whereas that of late winter spring is highly baroclinic in the stratosphere stratospheric poleward fluxes of heat and momentum both exhibit pronounced maxima during september october these result primarily from the stationary wave 1 contributions and the transients assume a secondary role although not as pronounced as the stationary wave seasonality seasonal differences in transient wave behaviour are also documented including three dimensional propagation characteristics and wave mean flow interaction diagnostics

the distribution and geochemistry of some trace metals in the bermuda coastal environment results of the analyses of the water column and sediments of the bermuda platform for cd cu fe mn ni pb and zn are presented the major process controlling the water column concentrations is physical mixing of open ocean waters with inshore waters which are polluted by a wide range of diffuse inputs sedimentation within the inshore waters plays a lesser but significant role as do fluxes from the sediments of fe and mn and possibly phytoplankton uptake of zn concentrations within the sediments are controlled by the formation of trace metal enriched clay organic particles in the inshore areas and their subsequent redistribution by sediment resuspension except for fe and mn which are largely associated with clay lattices

seasonal variability of the effect of coral reefs on seawater co2 and air sea co2 exchange there are complex physical and biological processes controlling the exchange of carbon dioxide co2 between the ocean and atmosphere in coral reef ecosystems the balance of biological processes such as calcium carbonate caco3 formation and organic carbon production can either lead to co2 being retained in the oceanic environment i e oceanic sink of co2 or returned to the atmosphere through gas exchange oceanic source of co2 what remains uncertain is the fate of co2 in reefs subject to seasonal change and the annual balance of air sea co2 flux in such systems here it is shown that the bermuda coral reef acts as a source of co2 to seawater overlying the reef the magnitude of this source of co2 varies seasonally in response to changes in the reef community between coral and macroalga dominated states reflecting changes in the net balance between calcification and organic carbon production with knowledge of the calcification rate 5 6 to 10 6 g caco3 m 22 d 21 and observed modification in seawater f co2 by reef metabolism rates 20 6 to 3 3 g c m 22 d 21 and seasonal patterns of macroalgal productivity were estimated whether the bermuda coral reef system acts as an oceanic sink or source of co2 to the atmosphere not only depends on this seasonal variation but more importantly depends on the pre existing air sea co2 disequilibrium of open ocean waters surrounding the reef system the bermuda coral reef system serves as a useful model for understanding the fate of co2 in other reefs particularly those reefs changing because of environmental stress

atmospheric trace elements at enewetak atoll 2 transport to the ocean by wet and dry deposition the concentrations of trace elements in precipitation and dry deposition are presented for samples collected at enewetak atoll 11 n 162 e during searex experiments in 1979 the concentrations of al sc mn fe co and th in rain are dominated by crustal material and for these elements wet deposition evidently exceeds dry deposition for most of these elements the present rates of atmospheric deposition at enewetak are similar to their mean rate of accumulation in sediments over the past 5 10 000 years suggesting that the air to sea exchange of particles is closely tied to the sedimentary cycle of the mid pacific noncrustal sources govern the concentrations of pb zn cu se and cd in wet and dry deposition samples analyses of dry deposition collected from a flat plastic plate indicate that the amount of material recycled from the sea surface varies markedly between samples and even though these estimates do not necessarily reflect the dry deposition to the ocean surface the results suggest that recycled sea spray often amounts to more than 50 of the total dry deposition of the enriched elements recycled sea spray also makes up a significant fraction of the total wet deposition of the enriched elements the net deposition rates of elements such as cu and zn are greater than or equal to their inputs from vertical mixing but the net deposition of pb clearly exceeds the input from upwelling the current net deposition rates of the enriched elements are also similar to their rates of removal to sediments these results indicate that air sea exchange processes may significantly affect the chemistry of trace metals in the open ocean

hafnium isotopes in arctic ocean water the first isotopic compositions of dissolved hafnium in seawater from across the arctic ocean are reported most samples from the four sub basins of the arctic ocean have values within error of an average of ehf 0 8 combined hf nd isotope compositions do not fall on the well established positive correlation for mantle and crustal rocks instead arctic waters have hf that is more radiogenic than that typically found in rocks with similar nd isotope compositions a feature previously found in ferromanganese crusts and waters from the pacific ocean arctic seawater samples generally fall on the lower part of the ferromanganese crust array reflecting influences of inputs from arctic rivers and interactions of shelf waters with underlying sediments arctic rivers have much higher hf concentrations 7 30 pm than arctic seawater 0 36 4 2 pm water from the mackenzie river has the least radiogenic hf with ehf 7 1 1 7 and plots furthest away from the ferromanganese crust array while waters from the ob yenisey and lena rivers have values that are indistinguishable from most arctic waters in the amundsen makarov and canada basins hf concentrations are highest at the surface and lowest in the deeper waters reflecting the influences of riverine inputs and of waters that have flowed over the extensive siberian continental shelves and have nd and hf characteristics that reflect water sediment interactions this is in contrast to the relatively low near surface hf concentrations reported for locations elsewhere the pacific water layer in the canada basin exhibits the highest value of ehf 6 8 1 8 reflecting the hf isotopic composition of waters entering the arctic from the pacific ocean mixing relationships indicate that a substantial fraction of the hf in the mackenzie river is lost during estuarine mixing the behaviour of hf from other rivers is less constrained

trace metals in bermuda rainwater the concentrations of cd cu fe mn ni pb and zn have been measured in bermuda rainwater factor analysis indicates that fe mn and pb have similar origins to acidic components derived from north america the other metals all behave similarly but differently to the acids sea salt even after allowances for fractionation apparently contributes minor amounts of cu pb and zn and uncertain amounts of fe mn and cd to atlantic ocean precipitation wash out ratios calculated from this data along with earlier measurements of atmospheric trace metal concentrations on bermuda are of the same order as those reported from other remote ocean areas the wet depositional fluxes of cu ni pb and zn to the western atlantic ocean are significant compared to measured oceanic flux rates however the wet depositional fluxes of fe and mn to this area are relatively small suggesting additional inputs while an excess wet depositional flux of cd suggests large scale atmospheric recycling of this element

visualizing the evolution of the stratospheric polar vortex in january 1992 from a gcm simulation of a period in easoe the evolution of the northern hemisphere polar vortex is examined by means of a sequence of three dimensional visualizations use is made of two key dynamical features the edge of the polar vortex and the height of the tropopause this technique clearly shows how the vortex is disturbed by an anticyclonic tropospheric anomaly and how this disturbance vertically propagates up the vortex an objective method for finding the edge of the vortex is presented

stratospheric polar vortex splits and displacements in the high top cmip5 climate models sudden stratospheric warming ssw events can occur as either a split or a displacement of the stratospheric polar vortex recent observational studies have come to different conclusions about the relative impacts of these two types of ssw upon surface climate a clearer understanding of their tropospheric impact would be beneficial for medium range weather forecasts and could improve understanding of the physical mechanism for stratosphere troposphere coupling here we perform the first multimodel comparison of stratospheric polar vortex splits and displacements analyzing 13 stratosphere resolving models from the fifth coupled model intercomparison project cmip5 ensemble we find a wide range of biases among models in both the mean state of the vortex and the frequency of vortex splits and displacements although these biases are closely related consistent with observational results almost all models show vortex splits to occur barotropically throughout the depth of the stratosphere while vortex displacements are more baroclinic vortex splits show a slightly stronger north atlantic surface signal in the month following onset however the most significant difference in the surface response is that vortex displacements show stronger negative pressure anomalies over siberia this region is shown to be colocated with differences in tropopause height suggestive of a localized response to lower stratospheric potential vorticity anomalies

on the subtropical edge of the stratospheric surf zone abstract the formation of a subtropical transport barrier in the wintertime stratosphere is investigated in the context of a high resolution shallow water model in which rossby waves are topographically forced on a zonally symmetric basic state two sets of experiments are performed in the first adiabatic set no dissipation or forcing of the mean state is imposed in the second set the layer thickness is relaxed to an equilibrium state taken to be representative of middle stratospheric radiative equilibrium temperatures it is found that in the adiabatic case only a very weak subtropical barrier forms for forcing amplitudes that generate realistically steep potential vorticity gradients at the edge of the polar vortex the vigorous wave breaking in the surf zone generates secondary waves that spread and in turn break well into the summer hemisphere in contrast the inclusion of relaxation to a realistic thermal equilibrium leads to the formation of a subtropical region of steep pv gradients the