convective momentum transport by rainbands within a madden julian oscillation in a global nonhydrostatic model with explicit deep convective processes part i methodology and general results abstractthe convective momentum transport cmt properties of 13 215 rainbands within a madden julian oscillation mjo event simulated by a global nonhydrostatic model are examined cmt vectors which represent horizontal accelerations to the mean winds due to momentum flux convergences of deviation winds are derived for each rainband the cmt vectors are composited according to their locations relative to the mjo center while a similar number of rainbands are detected in the eastern and western halves of the mjo convective envelope cmt vectors with large zonal components are most plentiful between 0 and 20 to the west of the mjo center the zonal components of the cmt vectors exhibit a coherent directionality and have a well organized three layer structure positive near the surface negative in the low to midtroposphere and positive in the upper troposphere in the low to midtroposphere where the longitudinal difference in the mean zonal wind across the mjo is 10 m s 1 on average the net acceler

heating and moistening of the mjo during dynamo in ecmwf reforecasts abstractreforecasts produced by the ecmwf integrated forecast system ifs were used to study heating and moistening processes associated with three mjo events over the equatorial indian ocean during the dynamics of the madden julian oscillation dynamo field campaign variables produced by and derived from the ifs reforecast ifs rf agree reasonably well with observations over the dynamo sounding arrays and they vary smoothly from the western to eastern equatorial indian ocean this lends confidence toward using ifs rf as a surrogate of observations over the equatorial indian ocean outside the dynamo arrays the apparent heat source q1 and apparent moisture sink q2 produced by ifs are primarily generated by parameterized cumulus convection followed by microphysics and radiation the vertical growth of positive q1 and q2 associated with the progression of mjo convection can be gradual stepwise or rapid depending on the event and its location over the broader equatorial indian ocean the time for con

the paleohydrology of lower cretaceous seasonal wetlands isle of wight southern england abstract the floodplain deposits of the wealden group lower cretaceous of the isle of wight southern england were formed in a seasonal wetland setting a type of environment widespread today along higher order tropical and subtropical river systems but rarely identified in the geological record the unit consists of four main lithofacies sheet sandstones with dinosaur footprint casts green gray mudstones with vertebrate remains abundant lignite pyrite and siderite spectacularly color mottled mudstones with goethite and locally pseudo anticlines and red mudstones with pseudo anticlines hematite and carbonate nodules the sheet sandstones are interpreted as crevasse deposits the green gray mudstones were deposited in shallow ponds on the floodplain which acted as sinks for debris released by local floods following wildfires the mottled mudstones represent surface water gley soils formed in seasonally waterlogged areas and the red mudstones resemble present day vertisols that formed on topographically elevated areas only intermittently flooded these mudstones show vertical transitions from one to another and although they could be interpreted as components of simple catenas the absence of associated facies changes implies that topographic differences were not the only control it is proposed that these three mudstone types formed as seasonal wetland catenas in which differences in soil drainage conditions resulted from variations in the flooding hydroperiod affecting areas with minor relief differences rather than drainage variability simply reflecting static topographic differences such seasonal wetland systems are rarely documented in the stratigraphic record despite being a widespread environment in present day tropical regions and the wealden deposits are used to identify criteria for the recognition of this important environment in the rock record these southern english wetlands are compared with other lower cretaceous wetlands from northern spain enabling hydrological factors which controlled deposition to be recognized

organisms and sediments relationships and applications the sixth lyell meeting of the geological society was held on 13 february 1992 major themes included advances in the study of trace fossils with emphasis on ichnofabrics and the use of skeletal accumulations shell and bone beds both in elucidating environmental change and in sequence stratigraphy of the 12 papers read at the meeting seven are published in this thematic set the papers presented cover topics which lyell did not himself discuss at any length with the exception of his classic study on the temple at puzzuoli nevertheless the theme of the meeting was aptly expressed by him arrangements of fossils in strata each stratum in fact however far it may now lie beneath the surface was once in the state of shingle loose sand or soft mud at the bottom of the sea in which shells and other bodies easily became enveloped by attending to the nature of these remains we are often enabled to determine whether deposition was slow or rapid whether it took place in a deep or shallow sea near the shore or far from land and whether the water was salt brackish or fresh elements of geology chapter 3 as well as honouring lyell it was befitting to remember robert w frey university of georgia athens who died on 1 january 1992 following a long fight against cancer much of his considerable research output was directly in the fields covered at the meeting over the past 20 years he pioneered the study of animal sediment

the barremian aptian arid phase in western europe abstract evidence is presented from nine areas in western europe speeton yorkshire southern north sea channel and weald basins southern england jeanne d arc lusitanian and aquitanian basins of the north atlantic continental margins lower saxony basin north germany the paris basin and southern france for a phase of aridity which began during the hauterivian middle barremian and continued to dominate the climate of the region until the mid aptian although conditions during this period were not uniformly dry throughout criteria for recognising arid environments include the occurrence of evaporites abundances of carbonate rich sediments red beds firmgrounds carbonate nodules and pyrite concretions depletion of kaolinite spore assemblages of limited morphological diversity and the presence of numerous coniferalean and cheirolepidiacean pollen grains the change from generally humid to dry climates during the barremian is thought to have been linked to a lowering of sea level the arid phase clearly falls within the time span of the first cretaceous oceanic anoxic event

zonal and vertical structure of the madden julian oscillation abstract a statistical study of the three dimensional structure of the madden julian oscillation mjo is carried out by projecting dynamical fields from reanalysis and radiosonde data onto space time filtered outgoing longwave radiation olr data mjo convection is generally preceded by low level convergence and upward motion in the lower troposphere while subsidence cooling and drying prevail aloft this leads to moistening of the boundary layer and the development of shallow convection followed by a gradual and then more rapid lofting of moisture into the middle troposphere at the onset of deep convection after the passage of the heaviest rainfall a westerly wind burst region is accompanied by stratiform precipitation where lower tropospheric subsidence and drying coincide with continuing upper tropospheric upward motion the evolution of the heating field leads to a temperature structure that favors the growth of the mjo the analysis also reveals distinct differences in the vertical structure

regression analysis of zonally narrow components of the mjo abstractrecent works have demonstrated that eastward propagating features smaller than zonal wavenumber 3 but with spatial structures similar to those of the madden julian oscillation mjo frequently develop over the indo pacific warm pool these signals are characterized by periods shorter than 4 weeks but since they occur as part of a spectral peak of the mjo they might be characterized by similar physics these zonally narrow features occur at any phase of traditionally defined 30 60 day mjo events but they occur most frequently in its active convective phase this work presents a linear regression analysis based on filtering in the wavenumber frequency domain to compare such signals with traditionally defined mjos and 15 30 m s 1 convectively coupled kelvin waves results show that the trough collocated with the easterly wind anomaly extends westward into the region of lower tropospheric westerly wind and deep convection in the zonally narrow slow signals and mjos the fast kelvin waves have a ri

a simple model of fjord and coastal circulation interaction abstract the dynamical interaction of a narrow fjord with a wind driven coastal regime is investigated using a linear two layer numerical model the coriolis acceleration is important in the coastal regime but assumed to he unimportant in the fjord dynamical because v 0 for a wide variety of wind conditions bottom topography and model parameters the wind forced coastal circulation with its geostrophic alongshore currants has a strong effect on the circulation within the fjord these geostrophic currents control the free surface and pycnocline displacement at the fjord mouth thereby strongly affecting fjord circulation this mechanism is an alternative to the classical idea of hydraulic control at the mouth by sills or constrictions model simulators also show that the free surface slope is a baroclinic effect and that alongshore and across shore winds affect the fjord differently alongshore winds produce flooding while up and down fjord winds simply sat up the surface we find that offshore win

propagating diurnal disturbances embedded in the madden julian oscillation 1 fine structure of large scale intraseasonal disturbance associated with the madden julian oscillation mjo was analyzed using the 3 hourly 3b42 trmm rainfall data over the maritime continent diurnal cycle becomes pronounced during the passage of mjo and the eastward propagating diurnal disturbances pdds dominate as an internal structure of large scale convection system of mjo importantly fast pdds that penetrate through the islands are observed within the slowly propagating mjo system this eastward penetration of pdds through the islands result in a sudden shift of the convection center from the western part of the islands to the east causing an overall propagation of the mjo from the indian ocean to the pacific our results demonstrate that the diurnal cycle of convection over and around the major islands thus plays an active role in the propagation of the mjo over the maritime continent

subtidal circulation in a deep silled fjord douglas channel british columbia douglas channel a deep fjord on the west coast of british columbia canada is the main waterway in the fjord system that connects the town of kitimat to queen charlotte sound and hecate strait a 200 m depth sill divides douglas channel into an outer and an inner basin this study examines the low frequency from seasonal to meteorological bands circulation in douglas channel from data collected at three moorings deployed during 2013 2015 the deep flows are dominated by a yearly renewal that takes place from may june to early september a dense bottom layer with a thickness of 100 m that cascades through the system at the speed of 0 1 0 2 m s 1 which is consistent with gravity currents estuarine flow dominates the circulation above the sill depth and the observed landward net volume flux suggests that it is necessary to include the entire complex channel network to fully understand the estuarine circulation in the system the influence of the wind forcing on the subtidal circulation is not only at the surface but also at middepth the along channel wind dominates the surface current velocity fluctuations and the sea level response to the wind produces a velocity signal at 100 120 m in the counter wind direction overall the circulation in the seasonal and the meteorological bands is a mix of estuarine flow direct wind driven flow and the barotropic and baroclinic responses to changes to the surface pressure gradient caused by the wind stress

a mechanism governing the estuarine circulation in deep strongly stratified fjords the estuarine circulation in deep strongly stratified fjords is discussed it is argued that a two layer description of the stratification in the fjord is correct in very wide fjords wide compared to the width of the mouth and possibly also in narrow fjords with high runoff and or weak mixing a theory for the thickness and the salinity of the brackish layer in a wide fjord was earlier developed by the present author and published in swedish 1975 and it is presented here among other findings in that theory we may mention that the thickness of the brackish layer is primarily determined by the internal hydraulic control for high specific runoff runoff unit horizontal surface area of the fjord and weak mixing in the other extreme with low specific runoff and strong mixing the thickness of the brackish layer is found to be proportional to the monin obukhov length the circulation in not very wide fjords is also discussed it is found that recirculation in the brackish layer may be expected whereby a two layer description of the flow field breaks down at least locally a critical rayleigh number that seems to control the recirculation of brackish water within the fjord is found a theory for the density difference between the mouth and the head in the brackish layer in the fjord is developed from the critical rayleigh number condition it is found that this density difference normally is proportional to the density difference between the brackish water at the mouth and the underlying sea water provided that the river runoff is not too heavy and or the mixing is not too weak this prediction is confirmed by extensive measurements from the nordfjord

satellite observations of tidal upwelling and mixing in the st lawrence estuary satellite thermal images noaa 9 of the st lawrence estuary are used to confirm the existence of a persistent cold spot due to tidal upwelling at the head of the lower st lawrence estuary and to show that cold water may be found episodically up to 100 km downstream of the head this extended cold anomaly may exist in two spatial configurations one confined to near the south shore the other being centered over mid estuary we discuss the various physical agencies likely to contribute to the growth of this anomaly and conclude that wind internal tides and advection of cold water from the head region are the most significant

horizontal and vertical structure of easterly waves in the pacific itcz abstract outgoing longwave radiation olr and low level wind fields in the atlantic and pacific intertropical convergence zone itcz are dominated by variability on synoptic time scales primarily associated with easterly waves during boreal summer and fall this study uses spectral filtering of observed olr data to capture the convective variability coupled to pacific easterly waves filtered olr is then used as an independent variable to isolate easterly wave structure in wind temperature and humidity fields from open ocean buoys radiosondes and gridded reanalysis products the analysis shows that while some pacific easterly waves originate in the atlantic most of the waves appear to form and strengthen within the pacific pacific easterly waves have wavelengths of 4200 5900 km westward phase speeds of 11 3 13 6 m s 1 and maximum meridional wind anomalies at about 600 hpa a warm moist boundary layer is observed ahead of the waves with moisture lofted quickly through the troposphere by deep co

equatorial dry air intrusion and related synoptic variability in mjo initiation during dynamo abstractdynamics of the madden julian oscillation dynamo was conducted over the equatorial indian ocean io from october 2011 to march 2012 during mid to late november a strong madden julian oscillation mjo event denoted mjo 2 initiated in the western io and passed through the dynamo observation array dry air intrusions associated with synoptic variability in the equatorial region played a key role in the evolution of mjo 2 first a sharp dry air intrusion surging from the subtropics into the equatorial region suppresses convection in the itcz south of the equator this diminishes subsidence on the equator associated with the itcz convection which leads to an equatorward shift of convection it is viewed as a contributing factor for the onset of equatorial convection in mjo 2 once the mjo convection is established a second type of dry air intrusion is related to synoptic gyres within the mjo convective envelope the westward propagating gyres draw drier air from the subtropics into the equa

observation of a quasi 2 day wave during toga coare abstract detailed structure of the quasi 2 day oscillation observed in the active phase of the madden julian oscillations during the intensive observation period of tropical ocean and global atmosphere coupled ocean atmosphere response experiment toga coare iop was described a variety of observational platforms is used including high resolution gms infrared histogram rain rate estimate from toga and mit radar measurements upper air soundings and boundary layer profiler winds from the integrated sounding system and surface data from the imet buoy the quasi 2 day mode had a westward propagation speed of 12 15 day 1 a horizontal wavelength of 25 30 longitude a coupling with the westward propagating n 1 inertio gravity waves was hypothesized from the space time power spectral distribution of the cloud field the wind disturbance structure was consistent with the hypothesis the vertical wave structure had an eastward phase tilt with height below 175 hpa and vice versa above indicating the wav

shelf fjord exchange driven by coastal trapped waves in the arctic in this article we show that the class of low frequency subinertial waves known as coastal trapped waves ctws are a significant agent of water volume exchange in a west svalbard fjord and by extension more widely along the west svalbard and east greenland margins where similar conditions prevail we show that ctws generated by weather systems passing across the sloping topography of the shelf break propagate into the fjord steered by the topography of an across shelf trough the ctws have characteristic periods of 2 days set by the passage time of weather systems phase speeds and wavelengths vary seasonally by a factor of two according to stratification winter summer values are cp 0 25 ms 1 0 5 ms 1 and 40 km 84 km ctw induced flow velocities in excess of 0 2 ms 1 at 100 m water depth are recorded observationally scaled ctw model results allow their explicit role in volume exchange to be quantified of the estimated exchange terms estuarine exchange is weakest qest 0 62 103 m3s 1 followed by barotropic tidal pumping qbt 2 5 103 m3s 1 with intermediary exchange dominating qi 2 4 104 m3s 1 oscillatory flows display greatest activity in the 1 5 day period band and ctw activity is identified as the likely source of variability in the 40 60 h period band within that band intermediary exchange driven by ctws is estimated as qictw ave 0 82 104 m3s 1 an exchange rate exceeding both barotropic and estuarine exchange estimates

baroclinic annular variability of internal motions in a patagonian fjord time series of horizontal velocities echo intensity wind velocity and atmospheric pressure were collected for 200 days in a patagonian fjord to explore pycnocline motions produced by the southern hemisphere s baroclinic annular mode bam the bam variability occurs between 20 and 30 days and is associated with fluctuations in atmospheric kinetic energy and in turbulent fluxes of heat spectra of horizontal velocities and normalized echo intensity in the fjord s water showed highest energy between 25 and 30 days this was explained by sustained westerly winds associated with extreme low pressure systems 900 hpa that had periodicity related to the bam wind forcing produced 40 cm s 1 along channel and cross channel currents in the surface layer which in turn created a wind induced setup toward the head of the fjord the setup was accompanied by a deepening of the pycnocline from 5 to 15 m depth with 25 to 30 day periodicity as derived from the normalized echo intensity the dominant empirical orthogonal function mode of the normalized echo intensity profiles explained 70 8 of the variance and also exhibited a 25 30 day periodicity further a wavelet and spectral analysis of 10 years of atmospheric pressure indicated peaks between 25 and 30 days each year indicating that the bam consistently influences weather patterns in chilean patagonia this is the first documented case of baroclinic annular variability in a specific region of the southern hemisphere and of its effects on fjord systems

the madden julian oscillation recorded in early observations from the tropical rainfall measuring mission trmm a satellite data analysis is performed to explore the madden julian oscillation mjo focusing on the potential roles of the equatorial rossby er and kelvin waves measurements from the tropical rainfall measuring mission trmm precipitation radar pr and visible infrared scanner virs are analyzed in the frequency wavenumber domain to identify and ultimately filter primary low frequency modes in the tropics the space time spectrum of deep storm fraction estimated by pr and virs exhibits notable kelvin wave signals at wavenumbers 5 8 a distinct mjo peak at wavenumbers 1 7 and periods of about 40 days and a signal corresponding to the er wave these modes are separately filtered to study the individual modes and possible relationship among them in the time longitude space in 10 cases analyzed here an mjo event is often collocated with a group of consecutive kelvin waves as well as an intruding er wave accompanied with the occasional onset of a stationary convective phase the spatial and temporal relationship between the mjo and kelvin wave is clearly visible in a lag composite diagram while the ubiquity of the er wave leads to a less pronounced relation between the mjo and er wave a case study based on the geostationary meteorological satellite gms imagery together with associated dynamic field captures the substructure of the planetary scale waves a cross correlation analysis confirms the mjo related cycle that involves surface and atmospheric parameters such as sea surface temperature water vapor low clouds shallow convection and near surface wind as proposed in past studies the findings suggest the possibility that a sequence of convective events coupled with the linear waves may play a critical role in mjo propagation an intraseasonal radiative hydrological cycle inherent in the local thermodynamic conditions could be also a potential factor responsible for the mjo by loosely modulating the envelope of the entire propagation system

palaeoenvironmental significance of storm coquinas in a lower cretaceous coastal lagoonal succession vectis formation isle of wight southern england thin bioclastic limestone beds coquinas in the vectis formation wealden group lower cretaceous of the isle of wight southern england exhibit a range of biofabrics and internal stratigraphies these features are attributed to both simple and complex storm deposition of allochthonous biogenic and siliciclastic materials in coastal lagoons and on adjacent mudflats these modes of deposition facilitated preservation of dinosaur trackways desiccation cracks shallow tier trace fossils and in situ bivalve colonies through rapid burial the coquinas thus preserve a record of surficial muds commonly lost through reworking the principal components of the coquinas comprise dispersed elements from within the argillaceous background facies some of these beds are laterally traceable for up to 27 km providing the foundations for a high resolution event stratigraphic framework

double diffusive convection in this paper we present a rather personal view of the important developments in double diffusive convection a subject whose evolution has been the result of a close interaction between theoreticians laboratory experimenters and sea going oceano graphers more recently applications in astrophysics engineering and geology have become apparent in the final section we attempt to draw some general conclusions and suggest that further progress will again depend on a close collaboration between fluid dynamicists and other scientists

sedimentology and palaeogeography of the regressive transgressive kurnub group early cretaceous of jordan abstract the early cretaceous kurnub group of jordan consists of three regressive transgressive fluvial marine depositional sequences in northern jordan recorded here for the first time whereas continental clastics dominated central and southern jordan deposition of the kurnub group started in the late neocomian above a regional angular unconformity by basal conglomerate and sandstone facies association of an alluvial braidplain origin during this time the tethys seaway was located to the north and northwest of jordan which afterwards during the barremian advanced in a south and southeastward direction flooding north jordan and giving rise to a tidal flat coastal swamp sequence following a subsequent regression of the sea unconfined braidplain deposits covered the area the most extensive transgression of the tethys inundated the region during the late aptian and early albian where a mixed siliciclastic carbonate sequence with interbedded inner shelf carbonates and tidal marsh coastal swamp black shales and lignites was deposited the next and last regression took place in the middle albian where a thin meandering river clastic sequence was deposited finally shallow marine sedimentation resumed over the region during the remaining time of the kurnub group which at the same time prepared for the subsequent regional cenomanian transgression upon comparison with global eustatic curves these three incursions of the tethys sea in jordan are to a great extent in accordance with the global sea level fluctuations the various formations of the kurnub group and their informal units that are established here for the first time can readily be correlated with equivalent deposits in adjacent countries the distribution of the shorelines of the barremian aptian and albian on both sides of the dead sea transform offers new evidence for 100 km northward displacement of the arabian plate against the sinai palestine plate

automated remote sensing of sediment plumes for identification of runoff from the greenland ice sheet the viability of employing sediment plumes emanating from outlets along the western margin of the greenland ice sheet as indicators of runoff is assessed an automated sediment plume quantification system based on daily 250 m moderate resolution imaging spectroradiometer modis band 1 reflectance imagery is developed coherent plumes are identified using spectral thresholds and polygon tracing validation employs imagery quality control procedures and manual verification of plume areas outlets at land terminating margins with wide and straight fjord geometries deliver the most accurate and consistent results plume area observations are also possible at marine terminating margins with relatively static fronts and low proximal sea ice concentrations variability in plume area is examined with reference to special satellite microwave imager ssm i derived daily melt extent at the hydrologic catchment scale at annual timescales plume areas tend to co vary with surface melt extent indicating that more mass is lost by runoff during years of extensive melting some synchronicity in plume areas from different catchments is apparent at seasonal and daily timescales plumes from individual outlets primarily relate to catchment specific melting

lagoonal sedimentation and fluctuating salinities in the vectis formation wealden group lower cretaceous of the isle of wight southern england abstract sedimentation in the shepherd s chine member of the vectis formation is characterised by a cyclicity of four principal facies on which a strong asymmetry has been imprinted by erosional events the four lithofacies are 1 very fine to fine sandstones 2 heterolithic sand silt and mudstones 3 parallel laminated pinstripe mudstones and 4 black mudstones the biota principally associated with lithofacies 2 and 3 as shelly partings and coquinas can be grouped into five molluscan associations which range from freshwater to quasi marine these associations are poorly correlated with the lithofacies but fluctuate within and between cycles salinity and storm frequency increase towards the top of the formation heralding the main marine aptian transgression lithofacies and biotas indicate deposition in a lagoon that was shallow and temporarily emergent the cyclicity is thought to represent the more distal phases of the advance and retreat of deltaic sand bodies derived from a westerly direction into the lagoon major storm events broke the symmetry of the cycles a deltaic facies represented by the barnes high sandstone member is thought to be laterally linked reworked deltaic sandstone lobes

effect of dry large scale vertical motions on initial mjo convective onset anomalies of eastward propagating large scale vertical motion with 30 day variability at addu city maldives move into the indian ocean from the west and are implicated in madden julian oscillation mjo convective onset using ground based radar and large scale forcing data derived from a sounding array typical profiles of environmental heating moisture sink vertical motion moisture advection and eulerian moisture tendency are computed for periods prior to those during which deep convection is prevalent and those during which moderately deep cumulonimbi do not form into deep clouds convection with 3 7 km tops is ubiquitous but present in greater numbers when tropospheric moistening occurs below 600 hpa vertical eddy convergence of moisture in shallow to moderately deep clouds is likely responsible for moistening during a 3 7 day long transition period between suppressed and active mjo conditions although moistening via evaporation of cloud condensate detrained into the environment of such clouds may also be important reduction in large scale subsidence associated with a vertical velocity structure that travels with a dry eastward propagating zonal wavenumbers 1 1 5 structure in zonal wind drives a steepening of the lapse rate below 700 hpa which supports an increase in moderately deep moist convection as the moderately deep cumulonimbi moisten the lower troposphere more deep convection develops which itself moistens the upper troposphere reduction in large scale subsidence associated with the eastward propagating feature reinforces the upper tropospheric moistening helping to then rapidly make the environment conducive to formation of large stratiform precipitation regions whose heating is critical for mjo maintenance

convectively coupled equatorial waves in high resolution hadley centre climate models abstract a methodology for diagnosing convectively coupled equatorial waves is applied to output from two high resolution versions of atmospheric models the hadley centre atmospheric model version 3 hadam3 and the new hadley centre global atmospheric model version 1 hadgam1 which have fundamental differences in dynamical formulation variability horizontal and vertical structures and propagation characteristics of tropical convection and equatorial waves along with their coupled behavior in the models are examined and evaluated against a previous comprehensive study of observed convectively coupled equatorial waves using the 15 yr ecmwf re analysis era 15 and satellite observed data the extent to which the models are able to represent the coupled waves found in real atmospheric observations is investigated it is shown that in general the models perform well for equatorial waves coupled with off equatorial convection however they perform poorly for waves coupled with equatorial convect

polynya impacts on water properties in a northeast greenland fjord abstract polynyas are an important yet poorly understood phenomena of high latitude oceans a storm event during late december 2013 with down fjord winds of up to 25 m s forced the collapse of the landfast ice over the young sound ys fjord outlet in northeast greenland this storm created a coastal polynya that was further maintained by several consecutive wind events until early march 2014 during the polynya period three landfast ice tethered oceanographic moorings recorded an enhanced surface layer 0 40 m transport towards the mouth of ys and a layer below 40 140 m flowing into the fjord and supplying the interior with cool and saline water from the polynya subsequent ctd transects in may 2014 reveal that this lower layer contained polynya originated cool saline and oxygen enriched water with oxygen concentrations significantly exceeding values from the previous summer salt balance bulk estimates show that the polynya generated a sufficient amount of brine to ventilate the fjord interior

sedimentary organic matter geochemistry of clayoquot sound vancouver island british columbia surface sediment samples from three interconnected fjords of clayoquot sound british columbia were density fractionated 1 6 g cm 3 to isolate discrete organic debris od from mineral associated organic matter mom total organic carbon oc values varied greatly ranging from 0 1 to 8 8 by weight with a general decreasing trend from fjord head to the continental shelf within the sediment terrestrial om was present either as vascular plant debris or soil mom down fjord the woody vascular plant material in the od fraction acquires nitrogen which is hypothesized to be due to the bacterial incorporation of nitrogen from the water terrestrial oc in the mom is incompletely replaced by marine oc within the fjords resulting in a 65 net loss of mom sediments deposited under oxic and intermittently anoxic water column conditions have organic carbon to surface area ratios oc sa ranging from 0 4 to 1 2 mg c m 2 similar to that of typical continental margin sediments given that temperate fjords contain an estimated 12 of the continental margin sediment deposited during the last 100 000 yr and that they bury at least a margin equivalent amount of oc either weight or surface area normalized we hypothesize that temperate fjords may contain 12 or more of the sedimentary oc buried during this time

wavelet analysis for geophysical applications wavelet transforms originated in geophysics in the early 1980s for the analysis of seismic signals since then significant mathematical advances in wavelet theory have enabled a suite of applications in diverse fields in geophysics the power of wavelets for analysis of nonstationary processes that contain multiscale features detection of singularities analysis of transient phenom ena fractal and multifractal processes and signal com pression is now being exploited for the study of several processes including space time precipitation remotely sensed hydrologic fluxes atmospheric turbulence can opy cover land surface topography seafloor bathymetry and ocean wind waves it is anticipated that in the near future significant further advances in understanding and modeling geophysical processes will result from the use of wavelet analysis in this paper we review the basic properties of wavelets that make them such an attractive and powerful tool for geophysical applications we dis cuss continuous discrete orthogonal wavelets and wavelet packets and present applications to geophysical processes

the rate of inflow and mixing during deep water renewal in a sill fjord we obtained high resolution data on a deep water renewal in the basin of gullmar fjord sweden using an autonomous profiling platform in the middle of the fjord where the platform is anchored renewal starts with the passage of a gravity current front and continues with a steady thickening of the new oxygen rich low nitrate bottom layer and an associated lifting of the old oxygen depleted high nitrate bottom water the basin continuously fills to sill level during a period of 10 d at the mouth of the fjord a three layer structure develops renewal is driven by the density difference between the intermediate water inside and the new deep water outside the fjord the volume flux is well predicted by a hydraulic exchange model in which the upper layer plays a passive role local upwelling and downwelling of the upper halocline cause fluctuating baroclinic currents during renewal but these seem to have little influence on the average volume flux of new deep water entrainment rates are small and the associated volume flux increase seems to be balanced by detrainment

new validation method for hydrodynamic fjord models applied in the hardangerfjord norway abstract we introduce a new intuitive evaluation method for comparison of fjord model results and current measurements the approach is tested using high resolution model simulations and measurements in the hardangerfjord a large fjord system in norway with huge aquaculture production the method is easy to interpret clearly distinguishes periods with good and poor model performance and relate them to physical driving forces this makes it possible to identify potential shortcomings in the models representation of physical processes the applied model mostly performs well in the hardangerfjord good performance often coincides with strong local fjord forcing i e strong winds in the fjord in periods with poor model performance internal waves induced by pressure perturbations on the coastal shelf tend to propagate erroneously into the fjord stratification biases in coastal waters connected to the applied model boundary conditions seems to be an important cause demonstrated flexibility of time frame and performance criteria suggests applicability of the validation method for a wide set of geophysical variables in various physical environments

propagation of the madden julian oscillation through the maritime continent and scale interaction with the diurnal cycle of precipitation the convectively active part of the madden julian oscillation mjo propagates eastward through the warm pool from the indian ocean through the maritime continent the indonesian archipelago to the western pacific the maritime continent s complex topography means the exact nature of the mjo propagation through this region is unclear model simulations of the mjo are often poor over the region leading to local errors in latent heat release and global errors in medium range weather prediction and climate simulation using 14 northern winters of trmm satellite data it is shown that where the mean diurnal cycle of precipitation is strong 80 of the mjo precipitation signal in the maritime continent is accounted for by changes in the amplitude of the diurnal cycle additionally the relationship between outgoing long wave radiation olr and precipitation is weakened here such that olr is no longer a reliable proxy for precipitation the canonical view of the mjo as the smooth eastward propagation of a large scale precipitation envelope also breaks down over the islands of the maritime continent instead a vanguard of precipitation anomalies of 2 5 mm day 1 over 10 6 km 2 jumps ahead of the main body by approximately 6 days or 2000 km hence there can be enhanced precipitation over sumatra borneo or new guinea when the large scale mjo envelope over the surrounding ocean is one of suppressed precipitation this behaviour can be accommodated into existing mjo theories frictional and topographic moisture convergence and relatively clear skies ahead of the main convective envelope combine with the low thermal inertia of the islands to allow a rapid response in the diurnal cycle which rectifies onto the lower frequency mjo hence accurate representations of the diurnal cycle and its scale interaction appear to be necessary for models to simulate the mjo successfully

seasonal mixing processes in an arctic fjord system abstract studies of water movement in the aafardlikavs qaumarujuk fjord system in west greenland have barn carried out in order to understand the movement of mine tailings discharged into agfardlikavs fjord observations are explained in terms of resonance of the internal tide deep convection associated with sea ice growth and basin water exchange occurring at the time of ice breakup in early summer mixing processes are dominated by these events illustrating the limitations of any seasonal description based on conventional diffusive processes

palaeoenvironmental analysis of mid cretaceous coastal lagoonal deposits lusitanian basin w portugal abstract the sedimentary record of fossil coastal lagoons is an under explored archive of environmental change in ancient coastal domains the significant continentality of coastal lagoons the small volumes of their water bodies very shallow depths and intermittent connectivity to oceanic aquafacies all result in a highly complex depositional system the matrix micrite chemostratigraphy carbon and oxygen isotope ratios of two mid cenomanian shallow coastal lagoon sections in the western lusitanian basin portugal are here presented in comparison to the geochemistry of different diagenetic carbonate materials geochemical evidence is placed against independent data from field observations sedimentology microfacies analysis and ostracod palaeoecology marine ingressions and coastal lagoonal environments are recorded both in sedimentological micropalaeontological and geochemical data sets intervals of more open marine conditions are evidenced by overall higher 0 to 2 carbon and less 18o depleted 3 isotope ratios the opposing pattern is observed for periods of more restricted lagoonal conditions the combination of a detailed ostracod palaeoecology with geochemical and sedimentological findings is considered a strength of this paper as it allowed to disentangle the complex geochemical signals of ancient coastal lagoonal deposits the comparison with recent coastal lagoons provided new arguments to clarify interpretations based on ancient records

kelvin wave time scale propagation features of the madden julian oscillation mjo as measured by the chen mjo index 1 kelvin wave time scale propagation features in an indexed measure of the strength of the madden julian oscillation mjo are investigated examination of reanalysis data and chen mjo index data for three 14 may to 21 september periods shows that recurring events near sumatra frequently associated with convectively coupled cc kelvin waves tend to correspond in a time lagged manner with increases in indexed mjo strength at various longitudes the events characterized by low level divergence within a cyclonic circulation off the west coast of sumatra combined with northward advances in the dynamic equator tend to lag increases in indexed mjo strength by several days in the indian ocean and maritime continent and to lead such increases farther to the east maximum time lagged correlation coefficients between increases in indexed mjo strength and a measure of the strength of the divergence events near sumatra are consistent with a disturbance propagating eastward at kelvin wave phase speeds a similar signal is demonstrated in a 32 year data set of the chen mjo index by examining time lagged correlations between increases in indexed mjo strength at various longitudes and corresponding increases for selected events at 80 e and 160 e the results suggest an enhanced rate of increase in mjo strength as the apparent kelvin wave signal passes roughly marking the beginning of an extended period of mjo growth potential limitations of the current analysis are discussed a look at a particular mjo episode provides evidence consistent with the statistical results while supporting a role of sequential cc kelvin wave passages in the propagation of the mjo

katabatic wind driven exchange in fjords the general issue of katabatic wind driven exchange in fjords is considered using an idealized numerical model theory and observations two regimes are identified for fjords narrower than a viscous boundary layer width the exchange is limited by a balance between wind and friction in lateral boundary layers for the nonlinear viscous parameterization used here this boundary layer thickness depends on the properties of the fjord such as stratification and length as well as on the wind stress and numerical parameters such as grid spacing and an empirical constant for wider fjords typical of east greenland the balance is primarily between wind the along fjord pressure gradient and acceleration in general agreement with previous two layer nonrotating theories it is expected that o 10 of the surface layer will be flushed out of the fjord by a single wind event application of the idealized model to a typical katabatic wind event produces outflowing velocities that are in general agreement with observations in sermilik fjord the presence of a sill has only a minor influence on the exchange until the sill penetrates over most of the lower layer thickness in which cases the exchange is reduced it is concluded that the multiple katabatic wind events per winter that are experienced by the fjords along east greenland represent an important mechanism of exchange between the fjord and shelf with implications for the renewal of warm salty waters at depth and for the export of glacial freshwater in the upper layer

forcing mechanisms and hydrodynamics in loch linnhe a dynamically wide scottish estuary abstract hydrodynamic conditions in loch linnhe a dynamifcally wide estuary on the west coast of scotland are primarily influenced by wind forcing freshwater input and tides winds in the region are orographically steered along the axis of the estuary due to surrounding mountains a large rainfall catchment area results in a large freshwater inflow into loch linnhe which in turn produces low salinity waters at the head of the estuary this combined with a connection to the open sea with coastal salinities leads to salinity gradients in the horizontal and vertical even though a range of observational programmes have focussed on loch linnhe the literature still lacks an evaluation of its physical dynamics here we present a first description of the hydrodynamics in loch linnhe based on observations wind stress predominantly influences the surface layer especially at low frequencies and with a stronger influence than tides during neap tides the buoyancy driven flow due to the large river runoff influences the circulation independent of wind stress seasonal spring autumn and interannual 2011 2012 variability of water masses occur especially in the surface layer tides are dominated by the semi diurnal constituent m 2 with tidal ellipses aligned in the along estuary direction and a stronger influence during spring tides compared to wind an evaluation of dimensionless numbers reveal laterally and vertically sheared exchange flows compared to other scottish estuaries loch linnhe is wide enough to be influenced by the earth s rotation and demonstrates an enhanced freshwater outflow along its north western coast as the freshwater is diverted to the right in the direction of the flow these observed patterns are important for the sustainable environmental management of this socio economically valuable region e g through their relevance to aquaculture pathogen transmission patterns a thorough understanding of the dynamics of the system is essential for a successful evidence based marine planning framework

the bude formation lower westphalian sw england siliciclastic shelf sedimentation in a large equatorial lake the 1300 m thick turbiditic bude formation was deposited in a lake lake bude but disagreement persists over whether the environment was a deltaic or deep water fan the tectonic setting of the lake was the northern flank of a northerly advancing variscan foreland basin close to the westphalian palaeo equator palaeocurrents indicate sediment sourcing from all quadrants except the south there is a dm m scale cyclicity whereby sandstone bodies comprising amalgamated event beds alternate with mudstone intervals containing non amalgamated event beds the ideal cycle is a symmetrical coarsening up fining up cycle consisting of three facies i 2 and 3 arranged in 12321 order facies 3 in the middle of the cycle is an amalgamated sandstone body up to 10 m thick which interfingers laterally with thin cm mudstone layers the sandstone body comprises amalgamated beds of very fine sandstone which are largely massive and up to 0 4 m thick channels are absent except for scours up to 0 2 m deep which truncate the interfingering mudstone layers sandstone bodies are inferred to be tongue shaped in three dimensions facies 1 and 2 completing the 12321 cycle are respectively dark grey fine and light grey coarse varved mudstone containing thin 0 4 m sandstone event beds fossils and burrows indicate that facies 1 and 2 were deposited respectively in brackish rarely marine and fresh water hence the ideal cycle 12321 reflects an upward decrease then increase in salinity brackish fresh brackish this is attributed to the lake sill being periodically overtopped by the sea due to glacio euitatic sea level oscillations the resulting oscillations in lake depth produced the coarsening up fining up regressivetransgressive cyclicity the central sandstone body representing the regressive maximum event beds are interpreted as river fed turbidites deposited during catastrophic storm floods combinedflow ripples and other wave influenced structures occur in event beds throughout the ideal cycle suggesting deposition of the entire bude formation above storm wave base the proposed environment is a shelf of continental shelf dimensions but lacustrine instead of marine sandstone bodies are interpreted to be river connected tongues or lobes the absence of cycles containing nearshore or emergent facies is attributed to i the lake sill preventing the water level from falling below sill level thereby insulating the lake floor from eustatically forced emergence and ii relatively distal deposition beyond the reach of shoreline progradations the lack of palaeoflow from the south is attributed to a now eroded deep water trough lying to the south in front of the northerly advancing orogen some facies 2 laminated mudstone beds grade laterally into massive and or contorted beds interpreted as in situ seismites facies 4 consistent with an active foreland basin setting development of seismites was possibly facilitated by gas bubbles and or weak cohesion in the fresh water bottom mud the late quaternary black sea with its broad northwestern shelf is probably a good physiographical analogue of lake bude and was likewise fresh at times

paleobiogeography and historical biogeography of the non marine caenogastropod family melanopsidae abstract we investigate the distributions of representatives of the family melanopsidae gastropoda caenogastropoda cerithioidea from the late cretaceous to present day the present contribution discusses and partly revises former schemes of melanopsid dispersal during the cenozoic all of which were based on outdated stratigraphic and tectonic concepts as well as an incompletely considered fossil record conflating a comprehensive and stratigraphically well constrained fossil record modern paleogeographical reconstructions and contemporary climate data our goal is to present a thorough model of melanopsid distribution and its changes over the cenozoic as well as its paleogeographical and climatic constraints the family melanopsidae evolved about 90 ma ago in the late turonian from brackish cerithioidean ancestors cretaceous and paleogene species occur in marginal marine to brackish environments along the shores of the tethys and paratethys seas the extant clades of melanopsis likely derive from the evolution of freshwater melanopsis on the balkan peninsula back in the late early miocene up to the pliocene freshwater species spread toward southwestern and southeastern europe and successively replaced brackish water representatives paralleling a general decline of latter systems during the late cenozoic the southwards expansion of melanopsis and its simultaneous retreat from northern latitudes resulted in the disjunct distribution pattern observed today the genus holandriana first appeared in northern italy in the late early miocene the genera microcolpia and esperiana both first occurred in the late miocene and likely derive from brackish water melanopsis species native to peri paratethyan lakes the present day biogeographic isolation of the three latter genera and melanopsis roots in the climatic deterioration and the disappearance of major lake systems in southeastern europe while thermophilous melanopsis retreated to the warm dry climates of the mediterranean and middle east holandriana microcolpia and esperiana adapted to the seasonal cold temperate climate of southeastern and eastern europe and some species became restricted to thermal springs

analysis of convectively coupled kelvin waves in the indian ocean mjo abstract the active convective phase of the madden julian oscillation hereafter active mjo comprises enhanced moist deep convection on its own temporal and spatial scales as well as increased variance in convection associated with higher frequency modes synoptic scale cloud superclusters apparently associated with convectively coupled kelvin waves occur within the active convective envelopes of most mjo events these convectively coupled kelvin waves also occur during the suppressed convective phase of the mjo hereafter suppressed mjo this observational study presents an analysis of outgoing longwave radiation and reanalysis data to determine how these waves behave differently as they propagate through the active and suppressed mjo time indices of the mjo and kelvin waves are derived for over the equatorial indian ocean dates of local extrema in these indices are used to composite data to discern how the waves and associated circulations behave on average then further composites are made based o

a climatology of waves in the equatorial region abstract propagating anomalies of moisture and moist deep convection in the tropics are organized into a variety of large scale modes these include but are not limited to the so called intraseasonal oscillations convectively coupled waves similar to those predicted by shallow water theory on the equatorial beta plane and tropical depression type disturbances along with the annual and diurnal cycles these modes act and interact to control much of the variance of tropical convection analyses of 10 yr of outgoing longwave radiation olr and precipitable water pw data are carried out to develop comparative climatologies of these wavelike modes the analysis relaxes the commonly used cross equatorial symmetry constraints which allows study of the portions of the wavelike processes that are asymmetric across the equator mean background states are found for olr and for pw as functions of day of the year examination of anomalies together with the background reveals much about how the waves are affec

evolution and hydrocarbon prospectivity of the brittany basin western approaches trough offshore north west france abstract the faulted preservation of a complete jurassic cretaceous succession in the brittany basin is primarily the result of early cretaceous rifting throughout the western approaches trough jurassic and cenozoic strike slip deformation has also contributed to the distribution of sedimentary successions now observed consequently the brittany basin has a different burial uplift history to the adjacent basins of the western approaches making the lias lower jurassic a mature source rock reservoir rocks are present but the unique deformation history has resulted in the late formation and possible breaching of structural traps the sedimentary record from the brittany basin allows us to observe the depositional effects of tectonic events occurring elsewhere in the western approaches trough these suggest middle jurassic early cretaceous late cretaceous and cenozoic uplift events each have different structural effects the origin of the most prominent intra mesozoic unconformity throughout the western approaches trough the early mid cretaceous is discussed with reference to causes of juxtaposed uplift and renewed rifting

on large scale circulations in convecting atmospheres the dominant thinking about the interaction between large scale atmospheric circulations and moist convection holds that convection acts as a heat source for the large scale circulations while the latter supply water vapour to the convection we show that this idea has led to fundamental misconceptions about this interaction and offer an alternative paradigm based on the idea that convection is nearly in statistical equilibrium with its environment according to the alternative paradigm the vertical temperature profile itself rather than the heating is controlled by the convection which ties the temperature directly to the subcloud layer entropy the understanding of large scale circulations in convecting atmospheres can therefore be regarded as a problem of understanding the distribution in space and time of the subcloud layer entropy we show that the subcloud layer entropy is controlled by the sea surface temperature the surface wind speed and the large scale vertical velocity in the convecting layer and demonstrate how the recognition of this control leads to a simple physically consistent view of large scale flows ranging from the hadley and walker circulations to the 30 50 day oscillation in particular we argue that the direct effect of convection on large scale circulations is to reduce by roughly an order of magnitude the effective static stability felt by such circulations and to damp all of them

sequence stratigraphic analysis of the aptian albian lower greensand in southern england abstract facies analysis and its use in sequence stratigraphy is described using the lower greensand of southern england as an example and the resulting interpretations are outlined this work forms an independent test of sequence stratigraphic techniques and the exxon cycle chart sequence stratigraphy is a very powerful tool in the analysis of problematic successions although some modification is made here in emphasizing the use of the transgressive surface changing palaeoenvironmental conditions and the effect that palaeoceanography has on the recognition of sequence boundaries are also discussed broad agreement is found between these results and the cycle chart although changing tidal conditions alter the criteria available for analysis of the aptian albian lower greensand succession comparison between this study and sequence stratigraphic analyses conducted in the more condensed type sections of england and france shows that further sequence boundaries are recognizable

vertical mixing rates in fjords determined using radon and salinity as tracers excess radon profiles were measured in several washington state and british columbia fjords generally exponential profiels were observed during periods of bottom water stagnation values of the vertical eddy diffusivity were estimated from the exponential excess radon profiles and from salinity changes in the stagnant bottom water these values ranged from 0 16 to 36 cm2 s 1 among fjords and the variation could be explained by different inputs of tidal energy into vertical mixing for the different fjords excess radon was also observed in surface water of several fjords the source of this excess radon was the freshwater runoff entering the fjords values of the vertical eddy diffusivity were estimated for the near surface water of narrows inlet from these profiles to be 0 32 to 0 47 cm2 s 1 across the freshwater saltwater interface and 0 9 to 3 1 cm2 s 1 between 5 and 35 m depth

where glaciers meet water subaqueous melt and its relevance to glaciers in various settings glacier change is ubiquitous but the fastest and largest magnitude changes occur in glaciers that terminate in water this includes the most rapidly retreating glaciers and also several advancing ones often in similar regional climate settings furthermore water terminating glaciers show a large range in morphology particularly when ice flow into ocean water is compared to that into freshwater lakes all water terminating glaciers share the ability to lose significant volume of ice at the front either through mechanical calving or direct melt from the water in contact here we present a review of the subaqueous melt process we discuss the relevant physics and show how different physical settings can lead to different glacial responses we find that subaqueous melt can be an important trigger for glacier change it can explain many of the morphological differences such as the existence or absence of floating tongues subaqueous melting is influenced by glacial runoff which is largely a function of atmospheric conditions this shows a tight connection between atmosphere oceans and lakes and glaciers subaqueous melt rates even if shown to be large should always be discussed in the context of ice supply to the glacier front to assess its overall relevance we find that melt is often relevant to explain seasonal evolution can be instrumental in shifting a glacier into a different dynamical regime and often forms a large part of a glacier s mass loss on the other hand in some cases melt is a small component of mass loss and does not significantly affect glacier response

role of pressure solution in the formation of bedding parallel calcite veins in an immature shale cretaceous southern uk bedding parallel fibrous calcite veins in black shales cretaceous southern uk were investigated using a combined field stable isotopic geochemistry petrographic and crystallographic method to examine their formation mechanism calcite veins occur in all shale beds and are most abundant in the bituminous shales of the chief beef beds the calcite fibres in these veins exhibit either an antitaxial fibre growth with curvy stylolites as the median zone or a predominantly syntaxial upwards growth the calcite veins range from 0 49 to 1 78 of 13c values and 6 53 to 0 03 of 18o values which are both similar to those of their host shales our petrographic observations demonstrate that subhorizontal and interconnecting microstylolite networks commonly occur within the calcite veins equant calcite grains in the median zones exhibit indenting truncating and also interpenetrating grain contacts it is interpreted that the fibrous calcite veins were sourced by neomorphic calcite from their host shales with evidence from the 13c signatures pressure solution features stylolites microstylolites and grain contact styles and embedded fossil ghosts within the veins the diagenetic fluids from which calcite was precipitated were a mixing of the original seawaters and 18o depleted meteoric waters development of bedding parallel calcite veins is considered to have been enhanced by pressure solution as a positive feedback mechanism which was facilitated by the overburden pressure as the maximum principal stress calcite fibres with a predominant subvertical c axis orientation exhibit a displacive growth in porous shales and a replacive growth at vein limestone contacts this study highlights the critical role of pressure solution in the formation of bedding parallel calcite veins during burial and diagenesis of immature black shales

evolution of precipitation and convective echo top heights observed by trmm radar over the indian ocean during dynamo radar data from the tropical rainfall measuring mission show the evolution of echo tops of convective elements over the indian ocean and maritime continent during the dynamics of the madden julian oscillation dynamo field campaign of 2011 2012 echo top heights exhibited a bimodal distribution wherein cumulonimbi of moderate height constituted a congestus mode while vertically extensive cumulonimbus made up a deep mode an intraseasonal time scale dominated variability in these modes from october to january over much of the indian ocean over the maritime continent there was no clear intraseasonal signal in convective echo top heights where the intraseasonal oscillation was detected radar echoes evolved from being dominated by the congestus mode to being characterized by more deep mode convection on time scales of less than 1 week the areal coverage of congestus echoes began to increase 2 8 days prior to the rise in area of deep echoes these satellite derived results confirm that the time scale for convective deepening seen at individual dynamo observational sites is consistent with that of convection on the large scale over the indian ocean intraseasonal variability of zonal wind temperature and humidity as depicted by reanalysis is also consistent with that derived from rawinsonde observations during dynamo thus the gradual buildup of convection as depicted by recent versions of the discharge recharge hypothesis does not accurately describe evolutions of convection prior to mjo events observed during dynamo although cloud moistening processes may still be relevant on time scales of 1 week or less

topographic effects on the eastward propagation and initiation of the madden julian oscillation abstract this study investigates the relationship between deep convection and heating anomaly in the madden julian oscillation mjo and the tropical topography the eastward propagation of the deep heating anomalies is confined to two regions the indian ocean and the western pacific warm pool superimposed on the eastward propagation is a series of quasi stationary deep heating anomalies that occur sequentially and discretely downstream in a leapfrog manner in the central indian ocean the maritime continent tropical south america and tropical africa the deep heating anomaly usually preceded by near surface moisture convergence and shallow heating anomalies tends to occur on the windward side of the tropical topography in these regions except the central indian ocean under the prevailing surface easterly anomaly of the mjo it is suggested that the lifting and frictional effects of the tropical topography and landmass induce the near surface moisture convergence anomaly which in turn triggers

convectively coupled equatorial waves 1 convectively coupled equatorial waves ccews control a substantial fraction of tropical rainfall variability their horizontal structures and dispersion characteristics correspond to matsuno s 1966 solutions of the shallow water equations on an equatorial beta plane namely kelvin equatorial rossby mixed rossby gravity and inertio gravity waves because of moist processes the tilted vertical structures of ccews are complex and their scales do not correspond to that expected from the linear theory of dry waves the dynamical structures and cloud morphology of ccews display a large degree of self similarity over a surprisingly wide range of scales with shallow convection at their leading edge followed by deep convection and then stratiform precipitation mirroring that of individual mesoscale convective complexes ccews have broad impacts within the tropics and their simulation in general circulation models is still problematic although progress has been made using simpler models a complete understanding of ccews remains a challenge in tropical meteorology

fluvial shallow marine glaciofluvial depositional environments of the ordovician system in jordan abstract the ordovician system cropping out in southern and west central jordan consists entirely of a 750 m thick clastic sequence that can be subdivided into six formations the lower disi formation starts conformably above the late cambrian umm ishrin formation according to cruziana furcifera occurring in the upper third of the disi formation an early ordovician age is confirmed the disi formation consisting mainly of downstream accretion da fluvial architectural element was deposited in a proximal braidplain flowing n ne from the southerly located arabian nubian shield towards the tethys seaway the braidplain depositional environment evolved into a braidplain dominated delta through the middle and upper parts of the disi formation and the lower part of the overlying um saham formation the delta was replaced by siliciclastic tidal flats that in turn evolved into an upper to lower shoreface environment through the upper part of the um saham formation the depositional environment attained the maximum bathymetric depth during the deposition of the lower and central parts of the third unit the hiswa formation where offshore graptolite rich mudstone with intercalated hummocky cross stratified tempestites were deposited the tethys seaway regressed back through the upper part of the hiswa formation promoting a resumption of the lower upper shoreface sedimentation oscillation between the lower to upper shoreface depositional environment characterized the entire fourth unit the dubaydib formation as well as the tubeiylliat sandstone member of the fifth unit the mudawwara formation the depositional history of the ordovician sequence was terminated by a glaciofluvial regime that finally was gradually replaced by a shoreface depositional environment throughout the last unit the ammar formation

sill processes related to deep water renewal in a fjord observations of the gravitational circulation over the sill at the entrance to puget sound indicate a fortnightly modulation of the two layer flow with a corresponding variation in stratification gravitational circulation and stratification reach a maximum during neap tides and a minimum during spring tides the modulation appears to be a function of the turbulence generation by tidal flow over the sill which varies as a function of tidal amplitude the enhanced gravitational circulation during neap tides augments the flux of dense water across the sill region and episodes of bottom water renewal in puget sound result intrusions of dense water in the main basin of the sound show a fortnightly periodicity with a phase lag appropriate for the propagation of an internal bore from the sill region commencing at the neap tide observations indicate that the intrusions take the form of gravity currents propagating at approximately 20 cm s 1 down the main basin the detailed dynamics of the turbulent mixing processes that modulate the onset of inflow were not resolved in this study but the integrated effect of tidal mixing on the low frequency circulation is clearly demonstrated

how systematic is organized tropical convection within the mjo 1 recent theories of the dynamics of the madden julian oscillation mjo have been building on its multiscale structure while it is observed that much of the convection within the mjo envelope is related to higher frequency equatorial waves it is not known to what extent this organization is systematic from one mjo event to another for instance it is of interest to know whether mjo favors waves of particular types and propagation direction and how this variability changes seasonally this work presents a wavenumber frequency spectral analysis of the mjo convective envelope which indicates that there is no strong preferred scale of high frequency organization that is ubiquitous to the mjo this null finding supports the use of convective parametrizations in modeling the mjo since while moist convection is likely critical to its initiation and maintenance the particular details of that organization may not be critical for its prediction and simulation

magnetostratigraphy of the lower cretaceous vectis formation wealden group on the isle of wight southern england magnetostratigraphic results are described from two sections within the lower cretaceous vectis formation formerly wealden shales of the isle of wight southern england the sections are located at shepherd9s chine and yaverland respectively in both of these sections a reliably established reverse polarity magnetozone herein defined as the vectis magnetozone occurs within the shepherd9s chine member this magnetozone has a thickness of some 15 m and its upper boundary is well defined in the yaverland section but is obscured in the shepherd9s chine section due to cliff slumping the lower boundary is well established in both sections and lies some 15 m above the barnes high sandstone member in the shepherd9s chine section and 12 m above this unit at yaverland this boundary provides a useful chron stratigraphic datum a comparison with established geomagnetic polarity timescales for the cretaceous indicates that the vectis magnetozone may be correlated either with lower aptian reverse polarity chron cm 0 or with lower barremian chron cm 1 with the former being the more likely an important implication of this interpretation is that the base of the aptian stage as defined from tethyan foraminiferal zones must lie within the vectis formation at least 25 30 m beneath the top of the shepherd9s chine member rather than at the top of this member as hitherto commonly accepted beds characterized by anomalously high intensities of magnetization which occur at the base of the vectis formation and a few metres above the barnes high sandstone in the two sections are tentatively interpreted as having a volcanogenic origin

modulations of the phase speed of convectively coupled kelvin waves by the itcz abstracta number of studies suggest a two way feedback between convectively coupled kelvin waves cckws and the intertropical convergence zone itcz viewed here as a proxy for deep convection analysis of brightness temperature data reveals several aspects of these interdependencies a wavenumber frequency spectral analysis is applied to the satellite data in order to filter cckws the itcz is characterized by a region of low brightness temperature and a proxy for both the itcz location and width are defined the phase speed of cckw data is determined using the radon transform method linear regression techniques and probability density analysis are consistent with previous theoretical predictions and observational results in particular the fastest waves are found when the itcz is the farthest from the equator and the narrowest conversely the slowest waves coincide with broad itczs that are located near the equator

an explosive convective cloud system and its environmental conditions in mjo initiation observed during dynamo an unusually large explosive convective cloud system was observed over the equatorial indian ocean on 28 november 2011 during the dynamo dynamics of the madden julian oscillation mjo field campaign the significance of this mesoscale convective system mcs is its size and explosive development of cold cloud tops 96 c during the initiation of a strong mjo event observations from the dynamo show that the large mcs developed within a well defined synoptic scale cyclonic circulation associated with an equatorial low pressure system with characteristics of a mixed rossby gravity wave that dominated the flow in the dynamo array prior to the development of the mcs the equatorial flow was characterized by strong vertical wind shear with low level westerlies and upper level easterlies a region of decreased wind shear and enhanced upper level divergence emerged concurrently with the passage of the westward moving mixed rossby gravity wave related low pressure system and convective activity in situ sounding observations suggest that widespread deep convection upstream of the large mcs may have contributed to the reduction of the upper level easterlies through vertical momentum transport and convective outflow both the reduction in vertical wind shear and enhanced low level convergence induced by the equatorial low pressure system created a favorable environment for the rapid development of the mcs this study examines the development of the mcs and the associated synoptic scale equatorial low pressure system within the large scale mjo circulation using in situ sounding observations from dynamo which provide new insights into the interaction between convection and environmental flow during mjo initiation over the equatorial indian ocean

the deepwater exchange cycle in indian arm british columbia abstract a silled fjord on the british columbia coast indian arm was used to study the exchange processes controlling deepwater exchange in fjords bottom water renewal took place during the winter of 1984 85 hydraulic control of the exchange is exerted over the long sill which restricts access to the fjord the maximum density at the sill occurs during neap tides no distinct peaks in the velocity at the sill are observed during periods of inflow reduced vertical mixing over the long sill during periods of neap tides sets the timing of the bottom water exchange during each inflow over the 1984 85 winter about 20 of the water in the fjord was replaced these exchanges occurred over periods of 5 10 days between the exchange years diffusion of the water in the basin is important in conditioning the water for the next exchange event the vertical diffusion coefficient k t was determined from an analysis of the salinity data and was found to be related to the buoyancy frequency n by the relationship k v n 1 6

frictional moisture convergence in a composite life cycle of the madden julian oscillation abstract a composite life cycle of the madden julian oscillation mjo is constructed using an index based on the first two eofs of the bandpass filtered 20 80 days 850 mb zonal wind averaged from 5 n to 5 s every 2 5 around the equator precipitation 1000 mb convergence 850 mb wind and 200 mb wind are composited for the period 1979 95 water vapor integrated from the surface to 300 mb is composited for the period 1988 92 frictional moisture convergence at the equator is shown to play an important role in the life cycle of the madden julian oscillation mjo regions of boundary layer convergence foster growth of positive water vapor anomalies to the east of convection this convergence coincides with 850 mb easterly wind anomalies as is consistent with kelvin wave dynamics drying of the atmosphere occurs rapidly after the passage of convection with the onset of 850 mb westerly perturbations possible mechanisms for this drying include boundary layer divergence and subsidence or horizontal advect

topographic influence on the mjo in the maritime continent abstract this study demonstrates that during the passage of the mjo through the maritime continent in the boreal winter the corresponding deep convection and near surface wind anomalies tend to skirt around mountainous islands flow bifurcation around elongated mountainous islands such as new guinea is clearly seen topographic blocking generates distinctive vorticity and convergence distributions in this specific domain mountain wave like structures are also observed throughout the maritime continent with a clear spatial relationship with the high terrains in sumatra sulawesi and new guinea the existence of topography seems to create extra lifting and sinking within the large scale circulation and thus the convective system exhibits quasi stationary features near the major topography during the mjo passage through the maritime continent it is suggested that resolving the detailed topographic effects may play a key role in simulating realistic characteristics of the mjo in the maritime continent

convectively coupled equatorial waves within the mjo during cindy dynamo slow kelvin waves as building blocks this study examines the relationship between the mjo and convectively coupled equatorial waves ccews during the cindy2011 dynamo field campaign using satellite borne infrared radiation data in order to better understand the interaction between convection and the large scale circulation the spatio temporal wavelet transform stwt enables us to document the convective signals within the mjo envelope in terms of ccews in great detail through localization of space time spectra at any given location and time three mjo events that occurred in october november and december 2011 are examined it is in general difficult to find universal relationships between the mjo and ccews implying that mjos are diverse in terms of the types of disturbances that make up its convective envelope however it is found in all mjo events that the major convective body of the mjo is made up mainly by slow convectively coupled kelvin waves these kelvin waves have relatively fast phase speeds of 10 13 m s 1 outside of and slow phase speeds of 8 9 m s 1 within the mjo sometimes even slower eastward propagating signals with 3 5 m s 1 phase speed show up within the mjo which as well as the slow kelvin waves appear to comprise major building blocks of the mjo it is also suggested that these eastward propagating waves often occur coincident with n 1 wig waves which is consistent with the schematic model from nakazawa in 1988 some practical aspects that facilitate use of the stwt are also elaborated upon and discussed

influence of the basic state zonal flow on convectively coupled equatorial waves observational data are used to test the hypothesis that the basic state modulates the dispersion properties of convectively coupled equatorial waves ccews this hypothesis is based on shallow water theory which predicts that the zonal speed of propagation of such tropospheric equatorial modes is altered by the equivalent depth and the basic zonal flow localized space time spectra are calculated to investigate how ccew spectral peaks vary across the tropics and how they are affected by the variations in zonal wind observed geographically and by season doppler shifting by the basic state barotropic zonal flow is readily identified once this doppler shifting is taken into account the equivalent depths of ccews inferred from global power spectra are surprisingly uniform both geographically and temporally however there are also detectable modulations that appear consistent with changes in vertical shear of the zonal flow along with other shifts that are not as easily explained

water mass characteristics and sill dynamics in a subpolar cold water coral reef setting at stjernsund northern norway the stjernsund located in subpolar setting at 70 5 n off northern norway hosts a thriving cold water coral reef community on a morainic sill dives with manned submersible jago identified the different reef zones and sedimentary facies on top and on the slopes of the sill hydrographic investigations indicate different water mass distribution east and west of the sill winter mode water and norwegian coastal water variability depends on the runoff and freshwater discharge into the fjord atlantic water dynamics are almost entirely tidally driven high resolution ctd time series covering a full tidal cycle demonstrate mixing processes occurring east of the sill additionally the different bathymetric distribution of living corals on the western and eastern slope of the sill portrays the dependence on these tidal dynamics the living corals thrive just below the isopycnal of 27 5 kg m 3 which marks the boundary between norwegian coastal water and atlantic water

eastward propagating 2 to 15 day equatorial convection and its relation to the tropical intraseasonal oscillation anomalies of outgoing longwave radiation olr in 1980 1989 were examined in a narrow latitude band about the equator to elucidate the propagation and interaction of tropical intraseasonal oscillations tios and synoptic scale convective activity hovmoller diagrams of olr data reconstructed from two frequency bands corresponding to periods of 30 60 days and 2 15 days respectively revealed a clear distinction between the phase speed of eastward moving tios 3 7 m s 1 and that of eastward synoptic scale convection 10 13 m s 1 coherent propagation of tios from the indian to the western pacific oceans was often observed with temporary diminution of amplitude over the maritime continent propagation of high frequency anomalies was generally confined to an individual basin dominance of eastward propagating synoptic scale convection in the equatorial zone contrasts sharply with the westward propagation of off equatorial convergence zones interaction between the tio and high frequency activity resolved by daily olr was visible as a modest enhancement of eastward synoptic scale events and of high frequency activity in general during the convectively active phase of the tio

the boreal summer madden julian oscillation and moist convective morphology over the maritime continent abstractwhile the boreal summer madden julian oscillation mjo is commonly defined as a planetary scale disturbance the convective elements that constitute its cloud dipole exhibit pronounced var

observations of a super cloud cluster accompanied by synoptic scale eastward propagating precipitating systems over the indian ocean the multiscale structure of a super cloud cluster scc over the equatorial indian ocean observed in november and december 2006 was investigated using data from satellite microwave sensors and surfacebased radars the smaller scale structure of this scc was marked by a complicated relationship between rainfall systems and upper tropospheric cloud shields which moved eastward and westward respectively with a cycle of 2 4 days in the analyses attention was given to the structure of slow eastward propagating 5 11 m s 21 precipitating systems and related synoptic scale 2000 km disturbances a case study of one of the systems revealed that it consisted of several lines of convective cells with a depth that was usually shallower than 10 km unless the cells encountered the westward moving cloud shields the environment of the convective lines was characterized by persistent unstable conditions with an increase of the westerly flow in the lower troposphere suggesting the existence of a synoptic scale upward motion composite analyses revealed that each rainfall system formed in a region of zonal flow convergence near the surface and divergence near 300 hpa the vertical temperature structure tilted westward with height below this pressure level and eastward aloft similar to that of a convectively coupled kelvin wave these results suggest that a scc involves a group of synoptic scale shallow waves propagating eastward an additional analysis over the western pacific also showed the predominance of eastward propagation in a scc demonstrating the advantage of satellite microwave sensors over infrared ones in monitoring the multiscale structure of tropical convection

baroclinic tidal currents in the gareloch scotland abstract acoustic doppler current profiler moored current meter and thermistor data were collected in the gareloch a sea loch on the west coast of scotland for 4 days during june 2001 the loch is approximately 8 km long 40 m deep in the interior and is separated from the clyde estuary by a sill at a depth of 16 m with respect to mean sea level the sill is situated in the narrows at the mouth of the loch where the tidal currents are barotropic in character and reach maximum speeds of about 0 3 m s in the interior of the loch where the barotropic tidal currents should not exceed 0 02 0 03 m s the flow was markedly baroclinic and reached speeds of 0 15 m s in the surface layer the surface and bottom layer flows displayed a 180 phase difference with the lower layer flow being directed landward during the flood tide the tidal currents did not display the expected semi diurnal motion that is characteristic of the clyde sea and estuary instead the motion was dominated by short period oscillations that appeared to be seiche related rather than due to shallow water tidal effects a strong inflow event observed at the mouth of the loch during a flood tide was consistent with the presence of a density driven current superimposed on the tidal flow the thermistor data showed that the loch was thermally stratified with a surface layer of thickness 8 10 m simulations with a two layered model that allowed for variable channel width and water depth reproduced the observed phase difference between the surface and bottom layers the model results suggested that the short period variability in the observed currents was related to interfacial oscillations generated by the strong tidal flow above the sill

two day disturbances in the equatorial western pacific from november 1992 to february 1993 westward propagating disturbances with scales of 1000 1500 km frequented the equatorial western pacific they propagated at about 16 m s 1 and their passage was accompanied by a two day oscillation in high cloudiness their convection was most intense when the lower troposphere was cool and the level of free convection was relatively low the disturbances propagated westward at about 18 m s 1 faster than the lower tropospheric flow this rapid propagation may have been the result of a coupling between the disturbance s convection and the 20 m s 1 vertical mode the signal of this mode was apparent in vertical profiles of temperature and wind and the most intense convection began when the mode dynamically cooled the lower troposphere lowering the level of free convection

multiscale variability of deep convection in relation to large scale circulation in toga coare deep convection over the indo pacific oceanic warm pool in the tropical ocean global atmosphere coupled ocean atmosphere response experiment toga coare occurred in cloud clusters which grouped together in regions favoring their occurrence these large groups of cloud clusters produced large scale regions of satellite observed cold cloud top temperature this paper investigates the manner in which the cloud clusters were organized on time and space scales ranging from the seasonal mean pattern over the whole warm pool region to the scale of individual cloud clusters and their relationship to the large scale circulation and sea surface temperature sst the dominant convective variability was associated with the intraseasonal oscillation iso a large eastward propagating ensemble of cloud clusters marked the iso s progress the meridional structure of the iso was strongly affected by the seasonal cycle with a southward shift from the northern hemisphere in october november to the southern hemisphere in january february the sst had an intraseasonal signal in lagged quadrature with the cold cloudiness and rainfall in coare the sst increased decreased during the convectively suppressed active phases of the iso enhanced low level westerly winds occurred toward the later stages of the enhanced convection periods of the iso though not always centered at the equator the strongest westerlies tended to be located between two synoptic scale cyclonic gyres which were often not symmetric about the equator in the low level wind field this asymmetry in the anomalous equatorial low level westerlies may have different implications for the oceanic response in the coupled atmosphere ocean system than those centered on the equator the cyclonic gyres contained highly concentrated deep convection and in four cases the gyres developed into tropical cyclones within the envelope marking the convectively active phase of the iso cloud clusters were frequently concentrated into westward propagating disturbances with a local periodicity of similar to 2 days these 2 day disturbances have been identified in earlier spectral studies and appear to be related to westward propagating inertio gravity waves in coare they typically contained numerous cloud clusters which underwent a distinct diurnal cycle most of the cloud clusters embedded in the 2 day disturbances moved westward though some were stationary and a few moved eastward a cloud duster tracking program identified groups of clusters lime dusters that exhibited continuity in time and space in the most convectively active period of the iso the tracking program identified almost the entire iso cloud ensemble as a long lasting trackable superconvective system this observation indicates the lack of a distinct scale separation between convection and large scale disturbances during the most intense convective periods in coare

a model study of density intrusions into and circulation within a deep silled estuary puget sound a laterally averaged hydrodynamical model is used to investigate episodic intrusions of denser more oceanic water across the shallow double silled entrance of puget sound and the resulting circulation within the interior deep basin tidal freshwater discharge and wind effects are also encompassed in model results model simulations were made of the 4 month period from december 1983 through march 1984 during that period hourly measurements of currents and salinity were made at the estuary entrance and on four moorings in the interior basin the first 60 days of salinity data were used with the model to choose rates of vertical turbulent mixing and the lag times between fresh water appearance at river gauges and its arrival in the main basin of the sound comparison of model results with the full 120 days of salinity and velocity data shows that the model incorporates the important circulation features of this estuary the model was then used to study intrusions and mixing in the sill region the model identifies these factors as controls on the occurrence and strength of intrusions the trans sill salinity gradient the intensity of tidal stirring and mixing over the sills the supply of fresher surface water resulting from river runoff and the winds time series of salinities in the interior basin show local maxima following local maxima in the trans sill salinity difference vertical transport in the sill region at both tidal and subtidal time scales is dominated by advection rather than diffusion though much of the vertical exchange occurs over the shallower sill a depth depression between the two entrance sills appears to be the site of significant overturning downwelling of surface water occurs on the landward side of both sills substantial freshening of the interior basin occurs during the winter months because river discharges are large and are stirred downward in the sill region to be entrained into landward bottom flows extraordinarily large river discharges can suppress the effect of large trans sill salinity differences with the effect of weakening potential intrusions winds can indirectly influence intrusions by longitudinally positioning fresher river influenced surface water in the sill region winds can directly influence intrusions via bottom compensation flows in admiralty inlet with northward winds encouraging intrusions and by changing salinities at the entrance to the sound and thus the trans sill salinity gradient

a tide generated internal waveform in the western approaches to the strait of gibraltar aircraft expendable bathythermograph radar infrared scanner and visual data collected in october 1982 1984 and 1985 as well as space shuttle photographs indicate that an internal waveform depending on flow conditions either an internal hydraulic jump or a lee wave is a semipermanent feature over the camarinal sill in the western approaches to the strait of gibraltar comparison of these data with both historic and recent current meter mooring data indicates that the waveform generated at the interface between the atlantic and mediterranean waters undergoes periodic changes wrought by interaction of the tidal current and the flow of the atlantic and mediterranean waters we believe that the waveform is a major mixing mechanism between the two water masses