upper ocean response to typhoon choi wan as measured by the kuroshio extension observatory mooring 1 the kuroshio extension observatory keo is a highly instrumented moored reference station located at 32 3 n 144 5 e in the recirculation gyre south of the kuroshio extension on 19 september 2009 the eye of typhoon choi wan international designation 0914 passed 40 km to the southeast of the keo surface mooring hourly meteorological and physical oceanographic measurements together with 3 hourly air sea carbon dioxide observations telemetered from keo in near real time show the evolution of the upper ocean and its associated air sea fluxes during the passage of this storm and its aftermath during the approach of the storm the mixed layer freshened because of intense rainfall this was followed by a large outgassing of co2 rapid cooling and an increase in salinity although these changes in mixed layer properties imply substantial entrainment they were accompanied by upwelling and ultimately a temporary 20 m shoaling of the mixed layer this upwelling which was observed at all depths including the deepest sensor near 500 m was coincident with the onset of near inertial oscillations in the mixed layer currents after the typhoon passed inertial pumping caused 15 20 m amplitude vertical displacements throughout the top 500 m that continued for at least 6 days a large oceanic response was observed in this case even though the eye of choi wan passed to the right of keo resulting in winds rotating cyclonically with time in opposition to the anticyclonic rotating near inertial currents

analyses and simulations of the upper ocean s response to hurricane felix at the bermuda testbed mooring site 13 23 august 1995 causedalargeincreaseinkineticenergyatnear inertialfrequencies internalgravitywavesin the thermocline and inertial pumping mixed layer deepening and significant vertical redistribution of heat with cooling of the upper 30 m and warming at depths of 30 70 m the temperature evolution was simulated using four one dimensional mixed layer models price weller pinkel pwp k profile parameterization kpp mellor yamada 2 5 my and a modified version of my2 5 my2 the primary differences in the model results were in their simulations of temperature evolution in particular when forced using a drag coefficient thathadalinear dependenceonwindspeed the kppmodelpredicted seasurface cooling mixed layer currents and the maximum depth of cooling closer to the observations than any of the other models this was shown to be partly because of a special parameterization for gradient richardson number rgkpp shear instability mixing in responsetoresolvedshearintheinterior themy2modelpredictedmoreseasurfacecooling and greater depth penetration of kinetic energy than the my model in the my2 model the dissipation rate of turbulent kinetic energy is parameterized as a function of a locally defined richardson number rgmy2 allowing for a reduction in dissipation rate for stable richardsonnumbers rgmy2 wheninternalgravitywavesarelikelytobepresent sensitivity simulations with the pwp model which has specifically defined mixing procedures show that most of the heat lost from the upper layer was due to entrainment parameterized as a function of bulk richardson number rbpwp with the remainder due to local richardson number rgpwp instabilities with the exception of the my model the models predicted reasonable estimates of the north and east current components during and after the hurricane passage at 25 and 45 m although the results emphasize differences between the modeled responsestoagivenwindstress currentcontroversyovertheformulationofwindstressfrom wind speed measurements including possible sea state and wave age and sheltering effects cautions against using our results for assessing model skill in particular sensitivity studies show that my2 simulations of the temperature evolution are excellent when the wind stress is increased albeit with currents that are larger than observed sensitivity experiments also indicate that preexisting inertial motion modulated the amplitude of poststormcurrents butthattherewasprobablynotasignificantresonantresponsebecauseof clockwise wind rotation for our study site index terms 4504 oceanography physical air sea interactions 0312 4572 oceanography physical upper ocean processes 4255 oceanography general numericalmodeling 4544oceanography physical internalandinertialwaves keywords hurricane tropical cyclone mixed layer modeling upper ocean processes inertial currents ocean storms

varying interplanetary magnetic field by effects on interhemispheric conjugate auroral features during a weak substorm 1 interhemispheric conjugate auroral features during a weak substorm interval were investigated using simultaneous all sky camera asc measurements at the northern and southern geomagnetic conjugate points at tjornes tjo 66 2 n 342 9 e in iceland and syowa station syo 69 0 s 39 6 e in antarctica around postmidnight just after the substorm onset the asc field of view fov at tjo was first filled with dynamic auroral activations however its counterpart was not detected over the zenith at syo at that time in contrast in the late stage about 20 min after the onset of substorm development we observed spiral like auroral arcs with a similar shape drifting eastward across the center of each asc fov although the one at tjo preceded the one at syo the time sequence of the interhemispheric conjugate auroral features was well reflected in the geomagnetic field variations at both stations on the basis of a detailed comparison of both asc images we identified that the northern geomagnetic footprint of syo was displaced poleward of tjo by up to 3 0 or more in the initial stage of substorm development whereas in the late stage it was displaced eastward by up to 1 h relative to tjo and then moved closer to tjo we emphasize that the dynamic motion of the conjugate points is a consequence of the time dependent magnetotail field reconfiguration process controlled by the varying interplanetary magnetic field by polarity

architectural features of the kayenta formation lower jurassic colorado plateau usa relationship to salt tectonics in the paradox basin abstract fluvial sandstones of the kayenta formation were analyzed using architectural element analysis paleocurrent trends the distribution of lacustrine facies and local silcrete development indicate that synsedimentary movement of evaporites in the underlying paradox basin created an unstable basin floor beneath the kayenta fluvial system this instability resulted in deflection of fluvial axes local basin development and local areas of interrupted fluvial deposition with eolian dunes paleocurrent trends in the kayenta system reflect periodic interruptions of southwesterly flow salt migrating laterally out of a rim syncline into an adjacent salt anticline resulted in a rim syncline of slight topographic relief the resulting basin was probably rapidly filled allowing the resumption of southwesterly flow differential movement of salt incipient solution collapse features resulted in the formation of small centripetal basins in which playa mudstones formed a laterally extensive resistant ledge underlies a horizontal surface suggestive of deflation to the water table of an exposed section of valley fill a channel scour in the top of one of these surfaces has margins much steeper 60 than the angle of repose for unconsolidated sand early cementation of the exposed floodplain could account for this resistance

upper ocean temperature response to hurricane felix as measured by the bermuda testbed mooring hurricane felix passed over the bermuda testbed mooring on 15 august 1995 providing a unique opportunity to observe the response of the upper ocean to a hurricane in the vicinity of bermuda felix was a particularly large hurricane with hurricane force winds over a diameter of about 300 400 km and tropical storm force winds over a diameter of about 650 800 km felix moved northwestward at about 25 km h21 with the eye passing about 65 km southwest of the mooring on 15 august peak winds reached about 135 km h21 at the mooring complementary satellite sea surface temperature maps show that a swath of cooler water by about 3 58 4 08c was left in the wake of felix with the mooring in the center of the wake prior to the passage of felix the mooring site was undergoing strong heating and stratification however this trend was dramatically interrupted by the passage of the hurricane as felix passed the mooring large inertial currents speeds of 100 cm s 21 at 25 m were generated within the upper layer the e folding decay timescale of the inertial currents was about 9 days the mixed layer depth was about 15 m before the arrival of felix and deepened to about 45 m within three days after felix s passage the temperature at 25 m decreased by approximately 3 5 8 4 08c large amplitude temperature oscillations 1 58c near the inertial period inertial pumping effect were set up by the hurricane in the seasonal thermocline resulting in vertical displacements of isotherms of approximately 15 m at 60 70 m comparative scale analyses of the upper ocean responses to hurricane felix and hurricane gloria 1985 indicate that they have several similarities

observations of the response of thermocline currents to a hurricane abstract in september 1985 the eye of hurricane gloria passed within about 100 km of a current meter mooring in the western north atlantic data from this mooring provide a clear view of the vertical structure of the near inertial wake in the main thermocline the response at 159 m was strong 25 cm s 1 amplitude and lasted about 18 days at greater depths the response was weaker and more irregular the phase of the near inertial currents increased with depth consistent with the downward spreading of enemy the total phase change across the thermocline reached about a half cycle seven days after the hurricane s passage indicating a large vertical scale of the response the observations are briefly compared with other time series measurements on the continental margin and with models

ichnology paleosols and palimpsests surfaces in the tinat member of the nuayyim formation unayzah group subsurface saudi arabia trace fossils and genetic stratigraphy in continental settings abstract the nuayyim formation of the unayzah group is widespread in subsurface central saudi arabia and constitutes a laterally variable stratigraphic unit with a complex mosaic of facies sedimentation for the tinat member took place majorly in a continental setting dominated by aeolian processes that resulted in dunes interdunes ephemeral stream deposits terminating with regional development of paleosols facies ichnofacies and palynological analysis suggest an arid to semi arid setting with biogenic activity in the form of continental fauna and plants in deposits associated with pedogenetical alteration in paleosol horizons therein burrowing exhibits elements of the scoyenia ichnofacies in beds with sparse to abundant bioturbation tectonic uplift and subaerial exposure resulted in the exhumation of previously buried substrates leading to the formation of burrowed palimpsests surfaces associated with paleosols at the end of unayzah deposition prior to the onset of the khuff formation progressive thermal updoming is interpreted to have occurred during the latest portion of the unayzah group sedimentation cycle in the arabian plate culminating in the regional pre khuff unconformity at the top of this megacycle recognized in this study by biogenically demarcated diastems ichnological and sedimentological observations outlined in this study are significant because they i refine existing interpretations of the paleoenvironmental history in the study area ii document diastems marking breaks in sedimentation and iii outline several soil forming cycles that allowed the establishment of a trace fossil suite with continental affinities thus demarcating the end of an entire sedimentation cycle the recognition and delineation of burrowed horizons associated with paleosols provides a tool to understand the tectono stratigraphic evolution of similar successions in the rock record

first observations of simultaneous interhemispheric conjugate high latitude thermospheric winds 1 we report the first observations of simultaneous high latitude interhemispheric f region neutral wind fields by combining the 630 nm optical measurements from two scanning doppler imagers sdis and three fabry perot interferometers fpis for a period exceeding 5 h from the southern hemisphere a sdi at mawson and a fpi at davis both in antarctica are geomagnetically mapped onto the northern hemisphere these data are combined in the northern hemisphere with a sdi at longyearbyen svalbard and two fpis near kiruna in sweden and sodankyla in finland geomagnetic conditions were moderate kp 3 3 and steady although the interplanetary magnetic field bz component did change polarity several times there is good agreement between the conjugate 630 nm optical intensities and wind vectors where the two sdis fields of view overlap all wind field vectors are overlaid onto the northern super dual auroral radar network ion convection contours qualitatively the agreement between neutral and ion flow is remarkably good throughout the study interval even down to mesoscale spatial size

forced stage response to a moving hurricane abstract the upper ocean s response to three hurricanes norbert 1984 josephine 1984 and gloria 1985 is examined using field observations and a numerical ocean model our goal is to describe the physical processes that determine the structure and amplitude of hurricane driven upper ocean currents all three of these northern hemisphere hurricanes produced a rightward biased response of the mixed layer current and transport this asymmetry arises because the wind stress vector rotates clockwise on the right side of the track and remains nearly parallel with the inertially rotating mixed layer current during most of the hurricane passage the maximum observed mixed layer current varied from 0 8 m s 1 in response to josephine which was a large but comparatively weak hurricane to 1 7 m s 1 in response to gloria which was very large and also intense these cases have been simulated with a three dimensional numerical model that includes a treatment of wind driven vertical mixing within the primitive

advective spreading of storm induced inertial oscillations in a model of the northwest atlantic ocean the spreading of inertial oscillations induced by the passage of hurricane juan 2003 across the gulf stream and the scotian shelf is examined using a regional model of the northwest atlantic ocean it is found that surface intensified inertial oscillations develop at locations remote from the storm track after a period of 5 10 days a diagnostic technique reveals the importance of advection by the background geostrophic flow for explaining this effect the results suggest that advection by mean circulation can play a role in redistributing near inertial energy in the ocean we argue that advective redistribution could have important consequences for understanding diapycnal mixing in the ocean

observations of the cold wake of typhoon fanapi 2010 1 several tens of thousands of temperature profiles are used to investigate the thermal evolution of the cold wake of typhoon fanapi 2010 typhoon fanapi formed a cold wake in the western north pacific ocean on 18 september characterized by a mixed layer that was 2 5 c cooler than the surrounding water and extending to 80 m twice as deep as the preexisting mixed layer the initial cold wake became capped after 4 days as a warm thin surface layer formed the thickness of the capped wake defined as the 26 c 27 c layer decreased approaching the background thickness of this layer with an e folding time of 23 days almost twice the e folding lifetime of the sea surface temperature sst cold wake 12 days the wake was advected several hundreds of kilometers from the storm track by a preexisting mesoscale eddy the observations reveal new intricacies of cold wake evolution and demonstrate the challenges of describing the thermal structure of the upper ocean using sea surface information alone

seasonal and interannual variability in deep ocean particle fluxes at the oceanic flux program ofp bermuda atlantic time series bats site in the western sargasso sea near bermuda abstract since 1978 the oceanic flux program ofp time series sediment traps have measured particle fluxes in the deep sargasso sea near bermuda there is currently a 20 yr flux record at 3200 m depth a 12 yr flux at 1500 m depth and a 9 yr record at 500 m depth strong seasonality is observed in mass flux at all depths with a flux maximum in february march and a smaller maximum in december january there is also significant interannual variability in the flux especially with respect to the presence absence of the december january flux maximum and in the duration of the high flux period in the spring the flux records at the three depths are surprisingly coherent with no statistically significant temporal lag between 500 and 3200 m fluxes at our biweekly sample resolution bulk compositional data indicate an extremely rapid decrease in the flux of organic constituents with depth between 500 and 1500 m and a smaller decrease with depth between 1500 and 3200 m depth in contrast carbonate flux is uniform or increases slightly between 500 and 1500 m possibly reflecting deep secondary calcification by foraminifera the lithogenic flux increases by over 50 between 500 and 3200 m depth indicating strong deep water scavenging repackaging of suspended lithogenic material concurrent with the rapid changes in flux composition there is a marked reduction in the heterogeneity of the sinking particle pool with depth especially within the mesopelagic zone by 3200 m depth the bulk composition of the sinking particle pool is strikingly uniform both seasonally and over variations in mass flux of more than an order of magnitude these ofp results provide strong indirect evidence for the intensity of reprocessing of the particle pool by resident zooplankton within mesopelagic and bathypelagic waters the rapid loss of organic components the marked reduction in the heterogeneity of the bulk composition of the flux and the increase in terrigenous fluxes with depth are most consistent with a model of rapid particle turnover and material scavenging from the suspended pool during new particle formation we suggest that much of the deep mass flux is generated in situ by deep dwelling zooplankton and that mass flux as well as scavenging of suspended materials from the deep water column varies in proportion to changes in grazer activity labile very rapidly sinking aggregates e g salp fecal material arriving in the bathypelagic zone within days of their upper ocean production may act to stimulate zooplankton grazing rates and increase large particle production and deep mass flux days to weeks in advance of the arrival of bulk of surface produced material this process could reconcile mean particle sinking rate estimates with the phase coherence observed between upper and deep ocean mass fluxes

satellite measurements of sea surface cooling during hurricane gloria hurricanes and other strong storms can cause important decreases in sea surface temperature by means of vertical mixing within the upper ocean and by air sea heat exchange here we use satellite derived infrared images of the western north atlantic to study sea surface cooling caused by hurricane gloria 1985 significant regional variations in sea surface cooling are well correlated with hydrographic conditions the greatest cooling up to 5 c occurred in slope waters north of the gulf stream where the seasonal thermocline is shallowest and most compressed moderate cooling up to 3 c occurred in the open sargasso sea where the thermocline is deeper and more diffused little or no cooling occurred in shallow coastal waters bottom depth less than 20 m which were isothermal before the passage of hurricane gloria there is a pronounced right side asymmetry of sea surface cooling with stronger by a factor of 4 and more extensive by a factor of 3 cooling found on the right side of the hurricane track these qualitative results are consistent with the notion that vertical mixing within the upper ocean is the dominant sea surface cooling mechanism of hurricanes

sedimentary architecture of an ancient linear megadune barremian neuquen basin insights into the long term development and evolution of aeolian linear bedforms linear aeolian bedforms are the most abundant bedform type in modern earth sand seas and are very common in our solar system despite their abundance the long term development of these bedforms and its impact upon the resulting sedimentary architecture in the geological record is still poorly understood the aims of this paper are to study the exposed record of an ancient linear megadune in order to discuss the factors that impact the development and sedimentary architecture of aeolian linear bedforms the outcrops of the ancient troncoso sand sea barremian neuquen basin argentina provide a unique opportunity to access a preserved megadune record with an external body geometry that unequivocally confirms its linear morphology architectural analysis of the bedform record reveals significant differences for several aspects of cross stratified set bodies and bounding surfaces and allows for the identification of three architectural complexes insights from deterministic models analysis of set body relative chronology and distribution suggest that complexes result from distinctive phases in bedform development it also clearly shows that the megadune s construction was achieved by expansion from a core where the oldest deposits are located and that its development was characterized by sustained growth and strong longitudinal dynamics factors that impact the development and architecture of linear bedforms are identified discussed and compared to bedforms of transverse dynamics finally a scheme of expected styles of sedimentary architecture for linear bedforms is presented this case study shows how growth can be a critical factor conditioning linear bedform architecture and indicates how the preservation of certain styles of sedimentary architecture in the geological record may not be as unusual as previously thought

mid wisconsinan eolian deposits of the kittigazuit formation tuktoyaktuk coastlands northwest territories canada the kittigazuit formation is a late quaternary sand unit commonly observed throughout the tuktoyaktuk coastlands and in subbottom sediments of the southern beaufort shelf stratigraphic and sedimentology data including sedimentary structures grain surface characteristics and heavy and light mineralogy assist in characterizing the deposit and indicate that it is eolian in origin plant and arthropod macrofossils suggest that although the summer climate during deposition was as warm or slightly warmer than today conditions were likely more arid permafrost is interpreted as being widespread during deposition accelerator mass spectrometry radiocarbon dates indicate that the kittigazuit formation was deposited between 37 and 33 ka bp the unit is therefore interpreted as a mid wisconsinan eolian dune deposit formed by reworking of underlying alluvial sediments of the kidluit formation under nonglacial conditions glaciogenic sediments overlying the kittigazuit formation indicate that glacial ice cover

effect of typhoon kalmaegi 2014 on northern south china sea explored using muti platform satellite and buoy observations data abstract based on observational data from a buoy mooring array and satellite remote sensing data for sea surface winds temperature and height during the passage of typhoon kalmaegi 2014 a systematic analysis is performed on the atmospheric and oceanic variables of winds sea level air pressure surface air temperature sensible and latent heat fluxes rainfall water temperature salinity and ocean currents kalmaegi passed through the south china sea scs with a mean non dimensional speed of 2 87 typical of a fast moving storm with a predominantly baroclinic oceanic response in addition to some well documented response features such as rightward biased intensifications in sea surface cooling and currents a much deeper mixed layer to the right side of the storm and a strong near inertial oscillation in the thermocline we here identify several new features as follows 1 the current velocity to the right side of the track decays faster than that to the left side 2 on the right side of the track the typhoon induced water temperature anomaly exhibits a three layered cooling warming cooling structure in the vertical with salinity and density anomaly profiles sharing a similar pattern 3 on the left side of the track the whole upper ocean is cooled whereas salinity shows no variation in the uppermost 20 m layer with a negative anomaly for water at depths from 20 to 50 m and a positive anomaly below 50 m the associated mechanisms are discussed in the text 4 the storm induced maximum cooling is not unique to kalmaegi 2014 in fact storms with tracks similar to that of kalmaegi 2014 may induce similar maximum cooling in the northern scs which may be useful in predictions of where such storms would induce the maximum cooling

composition and architecture of braided and sheetflood dominated ephemeral fluvial strata in the cambrian ordovician potsdam group a case example of the morphodynamics of early phanerozoic fluvial systems and climate change abstract two fluvial facies associations braided and ephemeral fluvial are recognized in strata of the cambrian ordovician potsdam group in the ottawa embayment and quebec basin in northeastern north america braided fluvial sedimentation was dominated by the migration of coarse grained sandy dunes and rare unit bars and local gravels that built up low relief 0 4 5 m thick downstream accreting compound bars in very wide and shallow braided channels rare meter scale confluence scours incision and filling of decimeter thick bypass channels and thin 7 cm overbank deposition also occurred ephemeral fluvial sedimentation was dominated by the progradation of lobate terminal splays most of which were deflated and or reworked into thin 10 95 cm sheets by eolian processes during the long recurrence intervals between floods these strata were locally incised by rare 0 3 1 9 m thick scour filling high energy supercritical bedform strata and decimeter thick bypass channels both braided and ephemeral fluvial deposits consist of meter scale stacked high order stratal units separated by horizontal laterally extensive surfaces recording the recurring buildup avulsion and finally abandonment of channel belts in braided fluvial strata of the potsdam the dominance of thin 2 m elongated compound bars with low relief 5 bar margins and internal accretion surfaces 15 suggest that braided channels and in channel compound bars expanded laterally with negligible increase in flow depth during periods of increased discharge in the absence of bank stabilizing vegetation similar to other examples of the pre vegetated sheet braided style however in areas where bedrock topography inhibited the lateral expansion of channels thicker compound braid bars 1 2 3 5 m with higher relief accretion surfaces up to 35 like those observed in post silurian and modern systems preferentially formed in relatively deep channels ephemeral fluvial deposits here are similar to ephemeral examples throughout geologic history in that they mostly comprise poorly confined sheet like terminal splays that accumulated in topographic lows however compared to several post silurian examples strata in the potsdam exhibit considerably more eolian reworking of splays and preservation of supercritical bedform strata a manifestation of greater rates of surface water infiltration due to a lack of sheltering by rooted plants and propensity for unconfined flooding finally in the upper part of the potsdam two regional ephemeral fluvial units are interstratified with two braided fluvial units providing evidence for shifts in regional climate the sharp areally extensive surfaces that separate these fluvial systems are interpreted to approximate time lines and therein provide a means for relative and absolute chronostratigraphic correlation these changes are correlated with documented late cambrian to earliest ordovician global climate fluctuations with semiarid conditions and related ephemeral fluvial systems corresponding to global cooling events at ca 491 and 487 ma

a reassessment of the integrated impact of tropical cyclones on surface chlorophyll in the western subtropical north atlantic the impact of tropical cyclones on surface chlorophyll concentration is assessed in the western subtropical north atlantic ocean during 1998 2011 previous studies in this area focused on individual cyclones and gave mixed results regarding the importance of tropical cyclone induced mixing for changes in surface chlorophyll using a more integrated and comprehensive approach that includes quantification of cyclone induced changes in mixed layer depth here it is shown that accumulated cyclone energy explains 22 of the interannual variability in seasonally averaged june november chlorophyll concentration in the western subtropical north atlantic after removing the influence of the north atlantic oscillation nao the variance explained by tropical cyclones is thus about 70 of that explained by the nao which has well known impacts in this region it is therefore likely that tropical cyclones contribute significantly to interannual variations of primary productivity in the western subtropical north atlantic during the hurricane season

conjugacy of isolated auroral arcs and nonconjugate auroral breakups fine examples of both conjugate and nonconjugate isolated auroral arcs were observed at two geomagnetically conjugate stations near l 6 syowa station in antarctica and husafell in iceland on september 12 1988 these events exhibited some interesting characteristics an auroral loop structure that appeared in both hemispheres was 2 0 times larger in the north south direction at syowa than at husafell this scale difference is greater than expected from the difference in geographic and geomagnetic igrf coordinates between the two points of observation however temporal and spatial variations in the loop structures were almost identical in both hemispheres after the disappearance of the loop structure closely conjugate auroras were formed nonconjugate auroral features appeared again at syowa on the poleward side while the equatorward auroras maintained conjugacy the nonconjugate aurora at syowa then began to break up showing fast moving vortex like structures auroral spirals at this time all auroral features at husafell seemed to have their conjugate counterparts in equatorward auroras at syowa and none exhibited rapid motions these conjugate auroras at husafell were gradually extending poleward while the corresponding features at syowa were compressed toward the equator and shrinking in size the onset of auroral breakup was about one minute earlier at syowa than at husafell the nonconjugate auroral features were reflected in corresponding magnetic field variations on the ground the events summarized above give interesting clues to the development and decay of auroral conjugacy and the question why the beginning of auroral breakup is not simultaneous at conjugate stations the time lag and nonconjugacy of auroral breakup in conjugate areas suggests that the triggering source of auroral breakup was not located near the equatorial plane in the magnetosphere but most likely in a localized region near the ionosphere in the southern hemisphere the nonconjugate auroral spirals also suggest the existence of asymmetrical field aligned currents

stratigraphic architecture of alluvial aeolian systems developed on active karst terrains an early pleistocene example from the ebro basin ne spain abstract during the early pleistocene fluvial alluvial and aeolian depositional systems interacted in the central ebro basin spain constructing wide alluvial plains over a neogene evaporite substratum fluvial sediments mainly longitudinal gravel bars and channels are interdigitated with gravel mass flow and distal mudflat deposits aeolian sedimentation is registered as aeolian dunes and sand sheets episodes of fluvial deposition alternated with periods of alluvial fan progradation and aeolian deposition these changes are related to climate driven water availability stratigraphic units and deformation structures show synsedimentary karstification of the evaporite substratum that although karst was not restricted to any particular climate scenario was probably favoured during periods of high water availability karstification conditioned the development of local sedimentary depocentres which in turn influenced the distribution of sedimentary subenvironments as well as the accumulation and preservation of aeolian dunes and lacustrine palustrine deposits stratigraphic architecture shows that thickening of the series due to karst subsidence did not occur homogeneously but was controlled by diachronous subsidence resulting in numerous angular unconformities in subsiding karst areas transport capacity was reduced and sediment preservation increased

tracing geomagnetic conjugate points using exceptionally similar synchronous auroras 1 we report on highly similar auroras that were simultaneously acquired with all sky tv cameras situated at two geomagnetically conjugate points at tjornes in iceland and at syowa station in antarctica during this event meso scale discrete auroras including both east west and north south directed auroral forms showed excellent similarity in terms of shapes movements and luminosity variations at both observatories using these data we were able to trace the temporal movements and displacement of auroras in the northern and southern hemispheres with a high spatial temporal resolution our results indicate that the geomagnetic conjugate point of one station moved 200 km in longitude and 50 km in latitude in one hour due to changes in topology of the geomagnetic field similar and dissimilar auroras appeared simultaneously in adjoining areas of sky in both hemispheres

interhemispheric observations of emerging polar cap asymmetries 1 in this paper we use simultaneous global uv images of the aurora in the two hemispheres to study differences in the polar cap boundary location we show that the northern and southern auroral ovals circumvent the same amount of magnetic flux providing additional evidence that the poleward boundary of the aurora coincides with the open closed field line boundary during a period of significant flux closure large asymmetries in the polar cap boundaries developed between the hemispheres the asymmetry was strongest in the regions where the polar caps contracted the most suggesting that emerging interhemispheric polar cap asymmetries is an intrinsic phenomenon during substorm expansions when magnetic flux closes rapidly in the tail utilizing the prolonged surveillance of the open closed boundary location we show that the growing asymmetries can be accounted for by differences in the ionospheric convection in the two hemispheres the observations suggest that the differences in convection were due to seasonal differences between the hemispheres and that the summer hemisphere responded more promptly to changes in magnetospheric convection than the winter hemisphere

simultaneous images of the northern and southern auroras from the polar spacecraft an auroral substorm 1 the first simultaneous images of the auroras in the northern and southern hemispheres with a single camera have been gained with the earth camera onboard the polar spacecraft with sufficient angular resolution to provide maps of the intensities an auroral substorm was fortuitously observed on 1 november 2001 when the spacecraft was favorably positioned to observe both auroras the auroral intensities during the onset and the early expansive phase were mapped into corrected geomagnetic coordinates the onset brightening at far ultraviolet wavelengths was first detected in the southern auroras and subsequently seen in the northern auroras about 1 min later on l shells of about 5 re during the early phases of the auroral expansive phase the southern aurora continued to be brighter the unequal auroral intensities in the two hemispheres suggest that there is strong coupling of the ionosphere and magnetosphere the mapping of the auroras revealed that there is a local time difference between the onset positions of about 40 min with the southern auroras positioned to the east relative to those in the north this displacement was also similarly detected in the quiet auroral regions which were not participants in the auroral substorm such displacements may be useful in developing improvements in the accuracy of global magnetic models that are important for determination of the position of the in situ particle and field measurements in the magnetosphere the greater brightness of the northern quiet time auroras by tens of percent as first reported by aircraft observations at visible wavelengths in both hemispheres has been verified by the more global view from the polar spacecraft

response of subsurface waters in the eastern arabian sea to tropical cyclones abstract thermister chain data at different depths for june 1998 cyclone in the arabian sea at a location 69 2 e 15 5 n which is about 60 km to the left of the cyclone track indicates subsurface warming below 60 m and inertial oscillations of temperature with a periodicity of about 2 days the oscillations continued for 15 days even after the cyclone crossed the coast the analysis of the buoy ds1 located at the same position also suggests a stabilized southward flow after about two weeks of the cyclone crossed the coast analysis of the buoy data for may 1999 cyclone in the same region also indicates similar pattern in order to investigate the effect of cyclone ocean interaction and primarily to understand the process for the subsurface warming 3 dimensional princeton ocean model is configured for the eastern part of the arabian sea the model uses high horizontal resolution of about 6 km near the coast and a terrain following sigma coordinate in the vertical with 26 levels the study focuses on surface cooling and temperature rise in the underlying waters and explains its mechanism through upwelling and downwelling respectively the simulations in concurrence with the observations suggest that the occurrence of subsurface warming precedes the surface cooling with a lag of a day as the cyclone advances ds1 the simulations also demonstrate local temperature stratification plays an important role for cooling of the upper ocean and warming of the subsurface waters and extent of warming is directly related to the depth of the thermocline

new chemical bio optical and physical observations of upper ocean response to the passage of a mesoscale eddy off bermuda a mesoscale eddy advected across the bermuda testbed mooring site over a 30 day period centered on july 14 1995 temperature and current measurements along with biogeochemical measurements were used to characterize the biological response of the upper ocean associated with the introduction of nitrate into the euphotic layer due to the doming of isotherms associated with the eddy complementary shipboard data showed an anomalous water mass which extended from a depth of 50 to 1000 m manifesting as a cold surface expression and warm anomaly at depth although mesoscale eddies are frequently observed in the sargasso sea the present observations are particularly unique because of the high temporal resolution measurements of the new instrumentation deployed on the mooring analyzers that measure nitrate plus nitrite were placed at depths of 80 and 200 m and bio optical sensors were located at depths of 20 35 45 71 and 86 m peak nitrate values of nearly 3 0 mm at 80 m and chlorophyll a values of 1 4 mg m 23 at 71 m were observed as well as a 25 to 30 meter shoaling of the 1 light level depth a doppler shift from the inertial period 22 8 hours to 25 2 hours was observed in several time series records due to the movement of the eddy across the mooring inertial pumping brought cold nutrient rich waters farther into the euphotic zone than would occur solely by isothermal lifting silicic acid was depleted to undetectable levels owing to the growth of diatoms within the eddy the chlorophyll a values associated with the eddy appear to be the largest recorded during the 8 years of the ongoing u s jgofs bermuda atlantic time series study bats program

integration of horizontal well geological data into reservoir descriptions rotliegende sandstone lancelot area southern north sea lancelot guinevere and excalibur are rotliegende group gas fields that were developed mainly by horizontal drilling horizontal well geological data from these fields are interpreted and integrated with vertical well data to evaluate the target zone and enhance the reservoir description lateral variations in reservoir quality and eolian facies are interpreted in a horizontal core borehole images and conventional electric logs are used to identify facies record the lateral extent and orientation of eolian dune cross bed sets characterize diagenetic trends and locate fractures through the uncored horizontal well sections the cored interval consists of gently dipping medium grained dune base strata separated by a set boundary from moderately steeply dipping fine grained dune top sediments permeability varies with grain size and is therefore greater in the dune base than the dune top in this cored section the main facies in the horizontal wells as a whole are of eolian dune interdune and fluvial to marine reworked eolian origin comparison of facies in horizontal and vertical wells defines reservoir units in the upper part of the formation that show large scale mound and intermound infilling geometries reflecting relic dune field geomorphology comparison of the lateral extents and heights of eolian cross bed sets and patterns of foreset bed dip vector swing suggest that the sets are strongly trough shaped in copyright 1997 the american association of petroleum geologists all rights reserved 1manuscript received may 25 1995 revised manuscript received march 6 1996 final acceptance august 14 1996 2robertson research international limited llandudno north wales ll30 1sa united kingdom current address robertson blackwatch ltd netherton business centre fetternear kemnay inverurie aberdeenshire ab1 5lx united kingdom 3mobil north sea limited 3 6 clements inn london wc2a 2eb united kingdom we thank mobil north sea ltd brabant oilex ltd and robertson research international ltd for permission to publish this paper we thank the following people for their helpful discussions peter corbett richard wood john ebbern peter lucas rob crossley and carl watkins and aapg referees peter hutchinson neil hurley and roy nurmi whose critical reviews helped improve the organization of the paper the opinions expressed and any misconceptions however are entirely ours

dust and pollution a recipe for enhanced ocean fertilization 1 for fe contained in aeolian dust to act as a micronutrient for oceanic phytoplankton some fraction of it must first be transformed mobilized into a form soluble in ocean water fe solubilization in deliquesced mineral dust aerosols emanating from east asia during the springtime outflow conditions is investigated here with a lagrangian box model of the gas and aqueous phase chemistry the model simulates the scavenging of soluble and reactive gaseous species by mineral dust aerosols chemical reactions of these species and mineral dust ions in deliquesced solution and dissolution of fe iii oxides that occurs as a result of the acid mobilization the calculations indicate that mineral calcite caco3 strongly buffers deliquesced dust aerosols with a ph that remains close to 8 until the amount of acid added to the aerosol solution exceeds caco3 alkalinity so2 pollutant emissions are a potential source of acidity to advecting dust from east asia the model is used to simulate the chemical evolution of dust plumes formed from two contrasting documented gobi desert storms that advected dust to fe limited regions of the north pacific ocean npo these calculations indicate that only plumes with relatively high initial so2 to dust ratios are capable of delivering significant amounts of bioavailable fe to the npo the estimated change in phytoplankton population inferred from the model calculated inputs of bioavailable fe for these two episodes is consistent with the satellite measured chlorophyll a concentrations in the npo model simulations indicate that 1 large dust advection episodes that can export vast amounts of mineral dust to the open ocean should have insignificant dissolved iron fraction dif as the amount of so2 required to acidify such dust plumes is about an order of magnitude higher than what can typically be entrained in the plume during its advection 2 smaller dust plumes will generally have higher difs because they require lower amounts of so2 and even if such small plumes may not cause algae blooms they could still be important sources of dissolved fe to the npo the calculations suggest that future changes in so2 pollutant emissions from east asia either up or down may affect the productivity of the npo

high resolution stratigraphic architecture and lithological heterogeneity within marginal aeolian reservoir analogues marginal aeolian successions contain different lithological units with variable geometries dimensions and spatial distributions such variations may result in considerable heterogeneity within hydrocarbon reservoirs developed in successions of this type which poses a high risk to their efficient development here such heterogeneity is described and characterized at inter well 1 km scales using two well exposed outcrop analogues of end member marginal aeolian deposits from the permian cedar mesa sandstone and jurassic page sandstone of south central utah usa the sedimentology and stratigraphic architecture of the cedar mesa sandstone was studied in a 1 2 km2 area in the indian creek region of southern utah where the interval consists of interbedded fluvial and aeolian deposits representative of a fluvial dominated erg margin the page sandstone was studied in a 4 3 km2 area near escalante close to the utah arizona border where it consists of interbedded sabkha and aeolian deposits representative of a transitional marine erg margin the three dimensional stratigraphic architectures of both reservoir analogues have been characterized in order to establish the dimensions geometries and connectivity of high permeability aeolian sandstones facies architecture of the aeolian sabkha deposits is characterized by laterally continuous aeolian sandstone layers of relatively uniform thickness that alternate with layers of heterolithic sabkha deposits aeolian sandstones are thus likely to form vertically unconnected but laterally widespread flow units in analogous reservoirs facies architecture in the aeolian fluvial deposits is more complex because it contains alternating intervals of aeolian sandstone and fluvial heterolithic strata both of which may be laterally discontinuous at the studied length scales aeolian sandstones encased by fluvial heterolithic strata may form small isolated flow units in analogous reservoirs although the limited continuity of fluvial heterolithic strata results in vertical connectivity between successive aeolian sandstones in other locations these architectural templates may be used to condition zonation schemes in models of marginal aeolian reservoirs

complexities in eolian and marine interactions processes and eustatic controls on erg development abstract the interplay between eolian and marine realms includes process interactions cycles of transgression and regression and possible inland effects of marine coastal events process interactions are geologically common and most obvious where eolian and marine environments are adjacent these interactions include sediment exchange between the two environments the supply of marine ions to the erg for surface and near surface cementation and the control directly or indirectly of marine events on the sediment budget of an erg regression accompanied by erg progradation over marine deposits occurs with both onshore and offshore winds marine transgression of ergs varies from producing a planar marine scoured surface to a planar deflation surface that precedes the transgression to varying degrees of paleotopographic dune preservation and a variety of transitional facies the extent of paleotopographic dune preservation is largely a function of the energy level of the transgressing marine realm the rate of the transgression and potential for early dune cementation general correlations between ergs and global eustatic sea level and coastal onlap curves occur for coastal and near coastal cyclic erg sequences eustatic control of inland ergs exists to the extent that sea level controls in large measure the extent of the basin exposed to subaerial processes i e regional base level and probably to a lesser extent the sediment supply to the erg direct correlation of inland erg events to coastal onlap curves is dubious at present but an indirect relationship may exist

distinctions and uses of stratification types in the interpretation of eolian sand abstract eolian and subaqueous cross strata cannot be distinguished reliably by many commonly cited criteria they can however generally be distinguished by the characteristics of their component types of stratification which represent processes of sorting and transport of the grain population on dunes eolian dune stratification types consist of grainflow cross strata grainfall laminae and wind ripple generated climbing translatent strata some of these types especially translatent strata have characteristics unique to the eolian realm these same stratification types are found to compose some ancient cross strata and their occurrence confirms the eolian interpretations of pans of the entrada jurassic navajo triassic jurassic and galesville cambrian formations a well as revealing emergent islands in the curtis formation jurassic previously considered to be totally marine in origin stratification types show a characteristic distribution on modern eolian dunes and differ in their relative abundances and structure on dunes of differing size and kind these same relations allow some estimates of the type shape and original height of ancient dune deposits as well as influencing the occurrences of surface features such as tracks and tipple forms the geological record of stratification types and other dune features is greatly affected however by the extent of the post depositional truncation of dunes

palaeoclimatic significance of co occurring wind and water induced sedimentary structures in last interglacial coastal deposits from bermuda and the bahamas response to hearty et al s comment abstract we respond to hearty et al s objections to our interpretation of upper pleistocene coastal landforms from bermuda and the bahamas as aeolian dunes rather than wave induced deposits their remarks concern the origin of fine scale laminae and fenestral pores observed in these landforms the apparent lack of steeply dipping foresets the inference that carbonate coastal dunes can migrate the vicinity of wave deposited boulders that we did not mention and finally the palaeoclimatic reconstruction we derived from our interpretation although we do not exclude and never did that occasional storm generated waves washed up and over these dunes and created some scours we maintain that these controversial deposits have an aeolian origin

on the simultaneity of substorm onset between two hemispheres simultaneous observations of auroral kilometric radiation from the northern and southern hemispheres showed some cases in which the buildup of field aligned acceleration occurred only in one hemisphere at the substorm onset this indicates that a substorm does not always complete the current system by connecting the cross tail current with both northern and southern ionospheric currents conjugate auroral observations showed that in one case the auroral breakup in the northern and southern hemispheres was not simultaneous rather they occurred a few minutes apart this time difference in the breakup between two hemispheres suggests that the local auroral ionosphere controls auroral breakup in each hemisphere independently the evidence in this study may indicate that the buildup of the field aligned acceleration region at the auroral breakup does not result only from the magnetospheric process and that the auroral ionosphere finally controls and or ignites the substorm onset that is the auroral breakup

upper ocean response to hurricane gonzalo 2014 salinity effects revealed by targeted and sustained underwater glider observations during october 2014 hurricane gonzalo traveled within 85 km from the location of an underwater glider situated north of puerto rico observations collected before during and after the passage of this hurricane were analyzed to improve our understanding of the upper ocean response to hurricane winds the main finding in this study is that salinity potentially played an important role on changes observed in the upper ocean a near surface barrier layer likely suppressed the hurricane induced upper ocean cooling leading to smaller than expected temperature changes poststorm observations also revealed a partial recovery of the ocean to prestorm conditions 11 days after the hurricane comparison with a coupled ocean atmosphere hurricane model indicates that model observations discrepancies are largely linked to salinity effects described results presented in this study emphasize the value of underwater glider observations for improving our knowledge of how the ocean responds to tropical cyclone winds and for tropical cyclone intensification studies and forecasts

coupling leeside grainfall to avalanche characteristics in aeolian dune dynamics avalanche grainflow processes are fundamental drivers of dune morphodynamics and are typically initiated by grainfall accumulations in sedimentary systems however the dynamism between grainfall and grainflow remains unspecified because simple measurements are hampered by the inherent instability of lee slopes here for the first time terrestrial laser scanning is used to quantify key aspects of the grainfall process on the lee slip face of a barchan sand dune we determine grainfall zone extent and flux and show their variability under differing wind speeds the increase in the downwind distance from the brink of peak grainfall under stronger winds provides a mechanism that explains the competence of large avalanches to descend the entire lee slope these findings highlight important interactions between wind speed grainfall and subsequent grainflow that influence dune migration rates and are important for correct interpretation of dune stratigraphy

3 2ga eolian deposits from the moodies group barberton greenstone belt south africa implications for the origin of first cycle quartz sandstones abstract the 3 2 ga moodies group in barberton greenstone belt south africa contains the oldest recognized evidence for eolian processes on earth these eolian facies indicate that significant wind regimes existed in the archean atmosphere eolian deposits are developed in the lower moodies group in the central part of the belt and consist of stacked inversely graded strata ranging in thickness from 2 to 10 mm individual strata consist of fine to medium grained quartz sandstone at the base that passes vertically into very coarse to coarse grained quartz sandstone strata make up cross bed sets up to 3 5 m thick sets of wind ripple strata are either tabular tangential or in the form of broad troughs this type of inversely graded stratification is the product of wind ripple migration the coarse grain size of the sediment combined with the low angle of inclination of the strata is best interpreted as the product of sand sheet or dune plinth preservation based on the geometry of eolian set boundaries dunes were probably simple barchan form the tens of meters thick eolian deposits are underlain by braided stream deposits composed of subfeldspathic pebbly sandstones the vertical change from braided stream subfeldspathic sandstones to eolian quartz arenites highlights the underappreciated capacity of eolian processes to generate first cycle quartz sandstones on landscapes pre dating the advent of land vegetation

an examination of the thermodynamic impacts of western north pacific tropical cyclones on their tropical tropospheric environment abstractthe present study examines the tropospheric thermodynamic anomalies induced by western north pacific tropical cyclone tc passage using storm relative composites negative moist static energy mse anomalies containing embedded westward propagating anomalies generally occur only following larger tcs for two months following tc passage in a region extending from the domain center to 3000 km to its west larger tcs force negative mse anomalies likely because of feedbacks from stronger broader tc induced negative sea surface temperature sst anomalies and the excitation of tc induced rossby waves to the southeast of the tc the negative mse anomalies are composed of lower and midtropospheric negative latent energy anomalies with smaller contributions from boundary layer and upper tropospheric negative sensible heat anomalies the lower and midtropospheric negative mse anomalies are forced by the tc whereas the upper tropospheric negative mse anomalies are forced by the madden julian oscillatio

observations and analyses of upper ocean responses to tropical storms and hurricanes in the vicinity of bermuda 1 a circular region within a radius of 400 km of bermuda has been struck by 188 tropical storms or hurricanes from 1851 through 2005 and by 20 since 1995 here we describe new direct and remote sensing observations and analyses of recent events near the bermuda testbed mooring including hurricane fabian 2003 tropical storm harvey 2005 and hurricane nate 2005 the most impressive upper ocean response of the recent events was produced by hurricane fabian when sst cooling exceeded 3 5 c vertical mixing occurred to a depth of greater than 130 m and upper ocean currents reached 100 cm s 1 fabian also triggered an ocean color event visible in seawifs satellite images related implications include improved estimates of the roles of tropical cyclones in driving meridional overturning circulation moc and testing of hypotheses concerning warming of the tropical oceans which could cause more intense tropical storms and hurricanes

uncertainty propagation in coupled atmosphere wave ocean prediction system a study of hurricane earl 2010 abstractthis study focuses on understanding the evolution of hurricane earl 2010 with respect to random perturbations in the storm s initial strength size and asymmetry in wind distribution we

last glacial aeolian landforms and deposits in the rhone valley se france spatial distribution and grain size characterization abstract in the rhone valley a north south oriented cenozoic rift in southeast france thick pleistocene loess deposits have been recognized since the beginning of the last century these loess records which are disconnected from the north european loess belt nelb are of significant interest to document the evolution of perimediterranean landscapes and environments during the last glacial to overcome the poor precision of available aeolian distribution maps aeolian deposits were mapped using the topsoil textural database provided by the land use and cover area frame statistical survey project lucas the grain size distribution of aeolian sand and loess was first determined using 116 samples taken from surveyed outcrops then the areas showing a similar grain size composition were extracted from the lucas rasters the resulting map reproduces the conventional maps correctly but suggests a more significant extension of loess in better agreement with the known distribution of outcrops the map shows that the distinctive morphology of the valley dominantly controls the distribution of aeolian deposits the deflation related landforms i e yardangs closed depressions pans and desert pavements are widespread south of narrowings of the rhone valley between latitudes 44 n and 45 n they indicate palaeowinds blowing from the north northwest aeolian sand loessic sand sandy loess and loess deposits successively spread on both sides of the rhone river the loess is characterized by a coarse texture main mode around 60 m strong local thickness 5 m limited extension and abundant bioturbation this preservation results from the persistence of a shrub vegetal cover during the coldest and driest phases of the last glacial that allowed for trapping the saltating and suspended particles close to the alluvial sources

the ocean boundary layer below hurricane dennis abstract three neutrally buoyant floats were air deployed ahead of hurricane dennis on 28 august 1999 these floats were designed to accurately follow three dimensional water trajectories and measure pressure i e their own depth and temperature the hurricane eye passed between two of the floats both measured the properties of the ocean boundary layer beneath sustained 30 m s 1 winds the floats repeatedly moved through a mixed layer 30 70 m deep at average vertical speeds of 0 03 0 06 m s 1 the speed was roughly proportional to the friction velocity mixed layer temperature cooled about 2 8 and 0 75 c at the floats on the east and west sides of the northward going storm respectively much of the cooling occurred before the eye passage the remaining terms in the horizontally averaged mixed layer heat budget the vertical velocity temperature covariance and the lagrangian heating rate were computed from the float data surface heat fluxes accounted for only a small part of the cooling most of th

numerical study of the storm induced circulation on the scotian shelf during hurricane juan using a nested grid ocean model a nested grid ocean circulation modelling system is used to assess the upper ocean response of the scotian shelf and adjacent slope to hurricane juan in september 2003 the nested grid system consists of a fine grid inner model covering the scotian shelf slope and a coarse grid outer model covering the northwest atlantic ocean the model calculated upper ocean response to hurricane juan is characterized by large divergent surface currents forced by the local wind forcing under the storm and intense near inertial currents in the wake of the storm the sea surface temperature sst cooling produced by the model is biased to the right of the storm track and agrees well with a satellite derived analysis over the deep water off the scotian shelf some of the near inertial energy input by the storm is advected eastward by the gulf stream away from the storm track the hurricane also generates shelf waves that propagate equatorward with the coastline on their right in comparison with the outer model results the inner model captures more meso scale structures greater sst cooling and stronger near inertial currents in the study region

the sensitivity of upper ocean structure to time varying wind direction observations and models show that sudden changes in the magnitude of the wind stress which occur within a time interval of one half inertial period are most effective in increasing surface current speeds and mixing the upper layers of the ocean the purpose of the present study is to quantify the effects of concurrent time dependent wind direction the mellor yamada level 2 1 2 turbulence closure model is used a series of model runs was executed in order to determine the relative sensitivity of mixed layer depth and sea surface temperature to wind speed as compared with the rate of change of wind direction the results indicate that the accuracy and time resolution of wind direction should be given special consideration in the design and interpretation of field experiments which will be used for testing prognostic mixed layer models

hemispheric asymmetry of the structure of dayside auroral oval a comprehensive analysis of long term and multispectral auroral observations made in the arctic and antarctica demonstrates that the dayside auroral ovals in two hemispheres are both presented in a two peak structure namely the prenoon 09 00 magnetic local time mlt and postnoon 15 00 mlt peaks the two peak structures of dayside ovals however are asymmetric in the two hemispheres i e the postnoon average auroral intensity is more than the prenoon one in the northern hemisphere but less in the southern hemisphere the hemispheric asymmetry cannot be accounted for by the effect of the interplanetary magnetic field by component and the seasonal difference of ionospheric conductivities in the two hemispheres which were used to interpret satellite observed real time auroral intensity asymmetries in the two hemispheres in previous studies we suggest that the hemispheric asymmetry is the combined effect of the prenoon postnoon variations of the magnetosheath density and local ionospheric conductivity

shallow marine and coastal eolian quartz arenites in the neoarchean palaeoproterozoic karutola formation dongargarh volcano sedimentary succession central india abstract the neoarchean palaeoproterozoic karutola formation a 200 m thick supermature quartz arenite occurs interlayered between two thick units of intermediate to basic volcanic rocks of the dongargarh group despite metamorphism and deformation detrital texture and sedimentary structures are well preserved allowing detailed process based facies analysis the facies recognised include 1 inner shelf 2 shoreface 3 delta mouth lower delta plain 4 tidal flat and 5 foreshore backshore a coastal sand sheet dominated by adhesion structures and consisting of alternating eolian and foreshore aqueous deposits records eolian processes operative in the karutola coastal area textural characteristics hint at a significant eolian contribution to the shallow marine sand overall palaeocurrent indicates a nw se shoreline trend with hinterland to the west of the present outcrop belt a surface indicating an abrupt increase in the water depth divides the formation into two units the lower part encloses inner shelf to foreshore backshore deposits and the upper part of the succession records deposition from the shoreface to lower deltaplain environment a tidal flat sandstone mudstone unit is developed only in the north western end of the study area a granite gneiss source terrain cropping out to the west and a hot humid climate appears to have supplied the abundant quartz sand to the karutola shoreline and the sand population attained textural maturity through eolian and aqueous reworking it is postulated that the aqueous eolian interaction inferred for the karutola sand should be common in sandy depositional environments that lacked land vegetation

large eddy simulations of upper ocean response to a midlatitude storm and comparison with observations abstract a large eddy simulation les model is used to investigate an upper ocean response to a fall storm in the open ocean of the north pacific ocean the storm is characterized by rapid increases in wind speed and surface heat loss but a relatively steady wave field the les model shows that surface convergence zones or windrows organize into line patterns aligned with the wind direction evolving from nearly parallel lines to irregular structures featuring y junctions as the wind speed increases the downwelling to upwelling velocity ratio ranges between 1 2 and 1 6 indicating a moderate level of asymmetry between the downwelling and upwelling plumes in langmuir circulation during the storm the turbulent langmuir number lat increases from 0 2 to 0 5 while the vertical turbulence intensity w2 decreases from 1 4 to 0 7 u 2 where u is the friction velocity the order of turbulence intensities in three directions switches from crosswind vertical downwind directions to downwind crosswind ver