sensitivity of the initiation of an isolated thunderstorm over the beijing metropolitan region to urbanization terrain morphology and cold outflows to gain insight into the processes leading to the convective initiation ci of an isolated thunderstorm near the central urban area cua of the beijing metropolitan region bmr on 9 august 2011 a series of numerical sensitivity experiments by removing or modifying the cua terrain morphology and convectively generated cold outflows is performed results show that the cua accounts for the formation of cloud condensation near the top of the mixed layer at the ci site as a result of the growing boundary layer depth through its urban heat island effects and urban induced convergence between a warm and moist southerly flow and an easterly flow on the downstream side the northerly approaching cold outflows from the mesoscale convective system mcs facilitate the generation of northerly flows through a northwestward concaved valley such that the enhanced low level convergence with the southerly and easterly flows near the cua could determine the timing of the outbreak of shallow clouds near the mixed layer top into an intense thunderstorm when the concaved valley on the northwest of the cua is eliminated little northerly flows ahead of the cold outflow boundaries into the ci site would be present the results obtained herein appear to have significant implications to understanding and forecasting the development of afternoon thunderstorms in the bmr under weak gradient environments

late pleistocene last interglacial terrace deposits bahia coyote baja california sur mexico abstract late pleistocene age terrace deposits are exposed in the narrow cliffed coastal plain of bahia coyote baja california sur resting unconformably on the lagoonal shallow water volcaniclastics of the early miocene cerro colorado member of the el cien formation the terrace is dissected by widely spaced arroyos and partically covered by alluvial fans in the inner and central areas the marine deposits vary in thickness from 0 5 to 10 m and were laid down in pre existing erosional channels and depressions in the pleistocene landscape the sequence begins with a cobble conglomerate with oyster shells overlain by poorly bedded molluscan rich bioclastic sands and coral rubble beds of massive porites in growth position and coral rhodolith sands and marls beach sands and gravels and coastal dunes cap the sequence samples of porites panamensis selected for u th dating are well preserved aragonite 95 preliminary results yield u th ages of 109 209 ka but the corals have initial 234u values in excess of modern seawater values this indicates open system behavior and uncertainty associated with the ages a corrected age for the top of the massive porites unit suggests that the corals grew during the last interglacial marine isotope stage mis 5e sea level high stand assuming global sea level during mis 5e was ca 4 5 m above present day sea level mcculloch and esat 2000 and the growth position of the corals was 1 5 m below sea level the terraces have been uplifted between 12 and 25 m 12 15 cm kyr this is consistent with other terrace based uplift rates for the central baja california peninsula north of the la paz fault

terrain trapped airflows and orographic rainfall along the coast of northern california part ii horizontal and vertical structures observed by a scanning doppler radar abstractthis study documents the mean properties and variability of kinematic and precipitation structures associated with orographic precipitation along the coast of northern california in the con

effects of melting on frontogenesis abstract frontal precipitation systems are simulated with a 2d cloud model including ice phase microphysics despite the use of idealized frontogenetic forcing in the simulations some observed characteristics of frontal zones and their associated cloud and precipitation fields are reproduced in the simulations the effects of melting snow on surface frontogenesis is investigated it is found that the cooling effects of melting snow significantly accelerate surface frontogenesis in winter storm environments especially when the melting layer is close to the surface however the steady state surface frontal strength in the model is not sensitive to the melting effects finescale thermal and kinematic perturbations inside the frontal zone near the melting level quite similar to those recently reported in the literature are evident in the model results analysis of the model results suggests that cooling from melting snow may induce these thermal and kinematic perturbations and may enhance baroclinicity

a multiwinter analysis of channeled flow through a prominent gap along the northern california coast during caljet and pacjet abstract experimental observations from coastal and island wind profilers aircraft and other sensors deployed during the california land falling jets experiment of 1997 98 and the pacific land falling jets experiment of 2000 01 2003 04 were combined with observations from operational networks to document the regular occurrence and characteristic structure of shallow 400 500 m deep cold airstreams flowing westward through california s petaluma gap from the central valley to the coast during the winter months the petaluma gap which is the only major air shed outlet from the central valley is 35 50 km wide and has walls extending at most a modest 600 900 m above the valley floor based on this geometry together with winter meteorological conditions typical of the region e g cold air pooled in the central valley and approaching extratropical cyclones this gap is predisposed to generating westward directed ageostrophic flows driven by along gap pressure differences two case studies and a fiv

tsunami imprints on the leeward netherlands antilles aruba curacao bonaire and their relation to other coastal problems abstract tsunami are one of the major natural hazards in the caribbean the historical record lists 88 tsunami from local events to teletsunami in the time period from 1489 to 1998 this study focuses on the spatial distribution and geomorphologic evidence related to coarse littoral sediment and boulder deposition by tsunami events of holocene age in the southern caribbean at a worldwide scale these debris deposits represent the most extensive and impressive records of holocene paleo tsunami so far studied hitherto the leeward lesser antilles consisting of the islands of aruba curacao and bonaire were not known to have had tsunami affecting their coastlines the possible contribution of tsunami to configuring coastlines e g the questions of embayment development the coastal environment changes and the absence of holocene fringing reefs along the windward coasts is discussed

the ancient shorelines of lanai hawaii revisited abstract three ancient shorelines the mahana kaluakapo and manele have been described at elevations of 365 190 and 170 m in the kaluakapo crater lanai hawaii bernice p bishop mus bull 237 1978 1 stearns original observation of a fossil bearing outcrop at 326 m was interpreted as an ancient shoreline subsequently moore and moore 1984 1988 science 226 1984 1312 geol soc am spec pap 229 1988 101 argued that stearns fossil evidence represented the highest inundation of tsunami waves associated with the collapse of the flanks of the hawaiian islands chain the giant wave hypothesis gwh subsequently stearns fossil bearing swale site has never been observed geological field studies of kaluakapo crater were conducted to clarify the nature of the highest coral bearing outcrops preserved on lanai these field studies found no support for a shoreline at 326 m however the field studies did document a shingle terrace with numerous coral clasts at 190 m elevation we find in situ fossil bearing marine deposits at 170 m elevation within kaluakapo crater furthermore we observe the undisturbed nature of marine deposits at 190 m the preservation of fine grained materials at 170 m the absence of in situ deposits with a biological component between 200 and 365 m the dearth of rounded boulders lacking weathering rinds between 200 and 365 m and the lack of post depositional burial of the terrace deposit despite loose debris being present on the high ground surrounding the 190 m terrace these observations lead us to believe that erosion by the hypothesized giant waves did not take place our observations are inconsistent with the giant wave tsunami inundation of the kaluakapo crater area thus we concur with stearns 1938 1978 geol soc am bull 49 1938 615 bernice p bishop mus bull 237 1978 1 jones 1993 jones a t 1993 elevated fossil coral deposits in the hawaiian islands a measure of island uplift in the quaternary phd dissertation department of oceanography university of hawaii 1 274 and grigg and jones 1997 mar geol 141 1997 11 that the coral bearing deposits on lanai represent ancient shorelines and reflect a history of uplift of the island associated with lithospheric deformation of the sea floor around the hawaiian hot spot

variability of sediment transport in beach and coastal dune environments brittany france abstract on the coasts of brittany english channel and bay of biscay barrier systems were surveyed between 1995 and 2000 the beach profiles have a very high variability which cannot be statistically explained by linear correlation with the wind the waves or the tides the behaviour of the profile is represented on a phase diagram speed of profile change y axis thickness of the profile x axis the points in the center of the profile rotate around an average equilibrium which is seldom measured in the field the seaward edge of the beaches oscillates between loss and gain but with a net positive budget the landward top of the beach displays a range of oscillations the dunes always have a positive budget the whole behaviour of the system is explained if the precise succession of anticyclonic and cyclonic winds is taken into account long periods of easterly winds offshorewards tend to produce a calm sea and to increase tidal sediment settling on the seafloor if an onshore westerly storm occurs just after such a period it hits a sediment rich environment and produces a net accumulation on both the beach and the dunes periods of westerly calm to moderate winds do not help accumulation a full going storm will hit a depleted environment and produce erosion the speed of dune accretion and the budget of the beaches seem to partly depend on the ratio of cyclonic to anticyclonic conditions

δ13c and c n as potential coastal palaeoenvironmental indicators in the mersey estuary uk the reconstruction of former environments and ultimately relative sea level changes in coastal and estuarine environments normally utilises a range of microfossil proxies such as diatoms foraminifera and pollen as microfossils are sometimes poorly preserved sparse or absent from coastal sediments this study assesses the potential of using 13c and c n analysis of sedimentary organic matter as an alternative contemporary high inter tidal and sub tidal surface saltmarsh sediments of the mersey estuary uk reveal distinctly different 13c and c n values reflecting the contrasting sources of organic matter in relation to ground elevation within the tidal frame despite decomposition effects the relationship between ground elevation 13c and c n is preserved in the sediment record with a gradual increase in 13c and decrease in c n from supra tidal through to inter tidal and to sub tidal environments holocene variations in 13c and c n are compared with stratigraphical palaeoenvironmental changes inferred from diatom and pollen evidence and show a good correspondence although 13c and c n are not as accurate as microfossil analysis in terms of coastal palaeoenvironmental reconstruction they may be applied successfully in the field of relative sea level reconstruction by helping to verify sea level index points when microfossils are absent

changes of relative sea level during the past 5000 years in the ancient harbor of marseilles southern france in the ancient harbor of marseilles marine fauna fixed upon archaeological structures as well as bio sedimentary units document a 1 5 m steady rise in relative sea level during the past 5000 years followed by a near stable level at present datum from about 1500 years ad to the last century this trend is similar to the one previously documented along the rocky coasts of the same region field observations inside and outside the harbor confirm that no sea level stand higher than the present ever occurred during the studied period in contradiction with the numerical model of peltier but in agreement with the glacio hydro isostatic models of lambeck and johnston and lambeck and bard q 2001 elsevier science b v all rights reserved

holocene sea level changes along the mediterranean coast of israel based on archaeological observations and numerical model local sea level curves reflect global eustatic changes regional isostatic adjustments of the crust to changing ice and ocean volumes and tectonically controlled crustal movements in this study we evaluate the relative contribution of each of these factors to the holocene sea level curve of the mediterranean coast of israel we use archaeological data as constraints on palaeo sea levels and we then compare the observational limits with isostatic models for sea level change across the region the isostatic model includes the contribution arising from the relative minor increase in ocean volumes for the past 6000 years due to residual melting of ice sheets the effect of the changing shape of the ocean basin the time dependence of shorelines as sealevel changes and the changing surface area occupied by ice sheets differences if significant between the observed and predicted change are interpreted as being of tectonic origin the archaeological observations and the model sea level curve along the mediterranean coast of israel were found to be generally consistent and any discrepancies lie within the uncertainties of both values our model predicted that 8000 years ago sea level at the israel coast was at about 213 5 2 m whereas the archaeological data place it at 216 5 1 m by 7000 bp the predicted level has risen to about 27 1 m consistent with the archaeological evidences according to both observations and predictions sea level was still lower than 2 3t o24 5 m at 6000 bp and remained below its present level until about 3000 2000 bp the comparison between the model sea level curve and the archaeological observations also enable to conclude that the average rate of vertical tectonic movement for the last 8000 years at the carmel coast israel has been less than 0 2 mm year q 2001 elsevier science b v all rights reserved

global glacial isostatic adjustment palaeogeodetic and space geodetic tests of the ice 4g vm2 model analyses of the global process of glacial isostatic adjustment and post glacial relative sea level change continue to deliver important insights into earth system form and process one successful model of the related phenomenology is based upon a spherically symmetric internal viscoelastic structure for the solid earth which has been denoted vm2 and a model of the most recent deglaciation event of the current ice age denoted ice 4g the primary purpose of this paper is to describe several new a posteriori tests that have recently been performed to further investigate the quality of this global solution to the inverse problem for both mantle viscosity and deglaciation history that is posed by the observables associated with this large scale geodynamic phenomenon i focus especially upon the misfits of observations to the theoretical predictions of this model which i am currently using to further refine its properties and upon predictions made using it of geophysical signals that should soon become visible in the context of the gravity recovery and climate experiment grace satellite mission among the required refinements to ice 4g one that is necessary to eliminate a recently revealed misfit to space geodetic constraints on the present day rate of radial motion at the yellowknife location well to the west of hudson bay and a similar misfit to absolute gravity measurements to the southwest of the bay is the insertion of a keewatin dome of thick ice centred over yellowknife with a ridge of ice extending to the south east in the geomorphological literature the existence of such a keewatin dome previously has been hypothesised but chronological control was lacking on the surface features that suggested its former existence an important additional constraint that requires the late glacial existence of this important feature consists of new inferences of the last glacial maximum lowstand of the sea from sites in the far field of the main concentrations of land ice copyright 2002 john wiley sons ltd

sea level during the penultimate interglacial period based on a submerged stalagmite from argentarola cave italy accurate constraints are presented for the absolute age duration and sea level for the highstand corresponding to marine isotope stage mis 7 1 our work is based on a stalagmite collected in a currently submerged cave from italy argentarola cave flooding of this coastal cave is clearly marked within the stalagmite by a thick marine overgrowth of serpulid worms precise uranium thorium u th ages measured by thermal ionization mass spectrometry suggest that the stalagmite growth varied in phase with climate during mis 7 2 and mis 6 the penultimate glacial period in addition the period of marine transgression is bracketed between 202 and 190 kyr bp defining a mis 7 1 duration of 11 2 kyr comparison with previous studies provides a new constraint on the sea level during mis 7 1 that has approximately remained between 318 and 39 m relative to present sea level the timing of the mis 7 1 highstand is in full agreement with the specmap chronology which contrasts with the growing body of evidence showing a significant phase difference for mis 5 5 a tempting conclusion is that second order sea level highstands such as mis 7 1 may be purely driven by astronomical changes in contrast with major terminations such as termination ii atmospheric co2 levels may partly explain this contrast since the two sea level transitions mis 7 2 7 1 and mis 6 5 5 are characterized by very different co2 rises 20 vs 100 ppm fl 2002 elsevier science b v all rights reserved

carbonate cementation patterns and diagenetic reservoir facies in the campos basin cretaceous turbidites offshore eastern brazil massive turbidite arkoses contain more than 80 of the oil reserves of the campos basin the main petroleum province of brazil the porosity and permeability distribution in the namorado albian cenomanian and carapebus turonian santonian sandstones is

coastline evolution at different time scales examples from the pomeranian bight southern baltic sea sedimentological and morphological changes on the upper and lower shoreface during relatively stable sea level highstand conditions have been investigated in the pomeranian bight southern baltic sea at time scales ranging from storm events to millennia in order to cover that variety of time scales different methods have been applied seasonal variations in the morphology of the upper shoreface were measured accurately using the tracer stick method the ratio of breaking waves and energy dissipation due to wave breaking are the main forces controlling redeposition on the upper shoreface with the depth of disturbance up to three times the net change the impact of single storm events can be observed from sidescan sonar mosaics to remain on the decadal scale aerial photographs covering the upper shoreface show that the location of gates channel like systems where water masses move offshore created during storm events also remain stable over decades sedimentological and geomorphological variations and changes on the lower shoreface are only measurable on the century to millennium scale because the main driving forces are longlasting processes like sea level fluctuations or neotectonics data on these scales have much more uncertainty in their relationship to forcing functions than data at shorter time scales because the effects of coastal processes active on different time scales can interact comprehensive understanding of large scale coastal behavior requires investigations from short events to long term processes c 2002 elsevier science b v all rights reserved

double bright band observations with high resolution vertically pointing radar lidar and profilers on 11 may 2010 an elevated temperature inversion associated with an approaching warm front produced two melting layers simultaneously which resulted in two distinct bright bands as viewed from the er 2 doppler radar system a vertically pointing coherent x band radar located in greenbelt md due to the high temporal resolution of this radar system an increase in altitude of the melting layer of approximately 1 2 km in the time span of 4 min was captured the double bright band feature remained evident for approximately 17 min until the lower atmosphere warmed enough to dissipate the lower melting layer this case shows the relatively rapid evolution of freezing levels in response to an advancing warm front over a 2 h time period and the descent of an elevated warm air mass with time although observations of double bright bands are somewhat rare the ability to identify this phenomenon is important for rainfall estimation from spaceborne sensors because algorithms employing the restriction of a radar bright band to a constant height especially when sampling across frontal systems will limit the ability to accurately estimate rainfall

high precision u series dating of corals from western australia and implications for the timing and duration of the last interglacial abstract u series ages using methods of thermal ionisation mass spectrometry tims are reported for last interglacial fossil reefs along the stable coastal margin of western australia thorium isotope ratios were measured with superior precision using methods of charge collection high levels of precision in the measurement of both uranium and thorium isotopes has reduced the age uncertainty due to analytical errors excluding the uncertainty in the decay constants by a factor of four over the precisions reported by many earlier tims workers uncertainties in 234u t determined from both 230th 238u and 234u 238u are also significantly smaller than previously reported allowing samples which have undergone diagenetic exchange of uranium and thorium to be more easily identified strict criteria were adopted to screen the new western australian data reliable ages range from 127 to 122 ka published tims observations from other localities have been assessed using the same strict criteria when these are combined with glacio hydro isostatic sea level models they indicate that the last interglacial period occurred from at least 130 to 117 ka however these age constraints are largely determined from single data points and need to be verified with additional ages before considering them to be robust estimates for the timing of onset and termination of the last interglacial globally the main episode of reef growth appears to be confined to a narrow interval occurring from 127 to 122 ka in direct agreement with the narrow range in ages obtained from the western australian sites this may indicate that the last interglacial was of short duration extending from 127 to 122 ka only alternatively this interval may reflect a major reef building event in the middle of a longer duration 130 117 ka interglacial interval

synoptic and topographic variability of northern california precipitation characteristics in landfalling winter storms observed during caljet abstract observations from northern california during the california landfalling jets caljet experiment are used to examine the mean characteristics of precipitation and their variances as functions of synoptic and topographic regimes ten cases involving the landfall of extratropical cyclones are analyzed with radar and rain gauge data collected at two sites one in the coastal mountains north of san francisco czd and the other in the central valley just west of sacramento kdax aside from the melting layer bright band the most striking feature in the 10 case composite vertical profile of radar reflectivity at czd was a distinct change in slope about 2 5 km above the bright band this shoulder is thought to represent a change in the growth rate of hydrometeors although the bright band was quite distinct about one third of the profiles in the composite did not exhibit this feature these nonbrightband nbb profiles had a low level slope where reflectivity increased with decreasing altitude a

predicted and observed holocene sea levels on the australian coast what do they indicate about hydro isostatic models in far field sites data relating to holocene sea level elevations and ages obtained by radiocarbon dating of relict calcareous skeletons of intertidal organisms from widely spaced parts of the australian coast a far field region of comparative tectonic stability are divisible into two sets namely pre and post ca 3600 yr bp the older ages are from material consistently between 1 5 m and 2 2 m higher than present sea level whereas the younger ages ca 3600 1500 yr bp generally cluster around 1 m above present sea level the elevations do not display any decline in amplitude from north to south over an extensive transect contrary to predictions by hydro isostatic models also there appears to be little difference between time elevation results for the coasts of north queensland new south wales and the bass strait region adjacent to tasmania despite differences in the width of the continental shelf in these three locations and the expectation of some hydro isostatic warping of the continental shelf subsequent to the onset of the holocene transgression results from the south and southwest coasts of western australia also display similar elevations to the east coast for the same time periods there is sufficient evidence extending over 20 of latitude to suggest that north south differences related to hydro isostatic influence is limited or non existent there is insufficient data to test hydro isostatic models across continental shelves hydro isostasy and the lithological elasticity it reflects may not be as pronounced in far field sites with narrow continental shelves as models predict stable far field passive continental margins may be the best place to measure the ratio of inputs of eustatic and hydro isostatic influences on holocene relative sea levels copyright 2002 john wiley sons ltd journal of quaternary science

recent shoreline mobility and geomorphologic evolution of macrotidal sandy beaches in the north of france abstract this paper examines shoreline mobility and sediment budget conditions on a sandy macrotidal coast with a well developed foredune aerial photographs and bunker archaeology covering the last 50 years were analysed in order to determine the meso scale evolution of le touquet beach in northern france both methods show that shoreline retreat has been negligible or very slow and has been accompanied by an elevation of the foredune dgps cross shore profiles show a balanced sediment budget over the last 7 years only a slight change of the beach face profile 0 2 0 5 m rise or fall was observed while the foredune exhibited a sharper change the french coast of the eastern english channel differs from that of the french atlantic coast which is currently being strongly eroded the balanced sediment budget of the former is attributed to sand inputs from nearshore banks which compensate exports due to longshore drift and to foredune development

a comparison of two coastal barrier jet events along the southeast alaskan coast during the sarjet field experiment abstract the southeastern alaskan regional jets experiment investigated the structures and physical processes of barrier jets along the coastal fairweather mountains near juneau alaska from 24 september to 21 october 2004 this paper compares in situ aircraft data and high resolution simulations from the first intensive observation period iop1 which featured a nearly terrain parallel barrier jet classical jet with another coastal jet event iop7 that was influenced by offshore directed gap flows at the coast hybrid jet iop1 featured southerly onshore flow preceding a landfalling trough which was blocked by the coastal terrain and accelerated down the pressure gradient to produce a 5 10 m s 1 wind enhancement in the alongshore direction in the lowest 1 km msl in contrast iop7 featured higher surface pressure and colder low level temperatures to the east inland of the study area than did iop1 which resulted in offshore directed coastal gap flow exiting cross sound below 500 m that turned a

on the origin of late holocene sea level highstands within equatorial ocean basins abstract late holocene sea level highstands of amplitude 3 m are endemic to equatorial ocean basins these highstands imply an ongoing and moderate sub mm yr sea level fall in the far field of the late pleistocene ice cover that has long been linked to the process of glacial isostatic adjustment gia clark et al 1978 mitrovica and peltier 1991 coined the term equatorial ocean syphoning to describe the gia induced sea level fall and they provided the first physical explanation for the process they argued that water migrated away from far field equatorial ocean basins in order to fill space vacated by collapsing forebulges at the periphery of previously glaciated regions we provide a complete physical explanation for the origin of equatorial ocean syphoning and the associated development of sea level highstands using numerical solutions of the equation that governs meltwater redistribution on spherical viscoelastic earth models in particular we separate the total predicted sea level change into contributions associated with ice and meltwater loading effects and by doing so isolate a second mechanism that contributes significantly to the ocean syphoning process ocean loading at continental margins induces a levering of continents and a subsidence of offshore regions that has also long been recognized within the gia literature walcott 1972 we show that the influx of water into the volume created by this subsidence produces a sea level fall at locations distant from these margins indeed over the major ocean basins that is comparable in amplitude to the syphoning mechanism isolated by mitrovica and peltier 1991

holocene aeolian morphogenetic phases in southern italy problems in 14c age determinations using terrestrial gastropods abstract radiocarbon age determination is one of the most important methods for dating holocene events in particular it has been used to reconstruct the sequence of aeolian morphogenetic phases along the apulia and basilicata coasts southern italy in these areas three main holocene morphogenetic phases have been recognized using radiocarbon data obtained from sub fossil terrestrial gastropods archaeological data and osl analyses those of the middle holocene period of the greek roman time and of the middle ages sub fossil terrestrial gastropods have been considered suitable indicators in the detecting holocene climate environmental changes however it is well known that they could show problems as chronological indicators mainly due to aging effects induced by i micro particles of calcite aragonite in the shell structure derived from the local substratum and ii a variation of co 2 content in the plants eaten in order to verify these hypotheses living terrestrial gastropods were collected from coastal areas and analysed using ams the results indicate that many living gastropods gave ages of 1500 years older than those expected thus confirming the aging effect as 14 c ages of middle and late holocene aeolian morphogenetic phases obtained from terrestrial gastropods seem to be confirmed by archaeological data and osl analyses the aim of this work is to verify if the age anomalies obtained from modern gastropods could be extended to the entire holocene period

the kinematics of orographic airflow during sierra storms abstract two case studies of the kinematics of the airflow over the sierra barrier are presented the observations consisted of rawinsondes and single doppler rhi and velocity azimuth display vad analysis of ppi scans the rhi scans were made orthogonal to the nearly two dimensional sierra barrier the cloud in the first case study contained a strong stable layer at 0 c while the second storm was highly unstable the radar bright band and soundings near the radar indicated that an 250 m thick 0 c isothermal layer was present in response to the diabatic process of melting when the bright band was impinging upon the barrier the associated 0 c isothermal layer was inferred to expand until it finally reached the ground at that point it was 1 km in depth direct thermodynamic soundings am presented for a similar situation which agrees with the modified soundings inferred for this study the resulting effects on the airflow and precipitation are discussed the unstable case contained a line of deep conve

the mesoscale and microscale structure of a severe ice pellet storm abstract on 1 2 february 1992 a major storm produced a prolonged period 6 h of ice pellets over st john s newfoundland at least two key features contributed to the prolonged duration first a subsaturated region within an inversion led to a reduction in the melting rate of particles that eventually meant that they could completely refreeze in the lower subfreezing region this subsaturated region formed within descending air aloft identified by doppler radar observations second a cold core of air between the surface and the inversion was critically important for the refreezing of partially melted particles results from an airmass transformation model were used to show that the ice pellet duration was extended as a result of air traveling over sea ice as opposed to over the ocean in addition this study showed that doppler radar velocity information may be capable of estimating the base height of the above freezing temperature regime during freezing rain drizzle furthermore the doppler velocity

sedimentary record of a tsunami during roman times bay of cadiz spain abstract historical data show that the gulf of cadiz has been exposed to destructive tsunamisduring at least the past 2000 yr the last tsunami was generated by the ad 1755 lisbon earthquake which affected the atlantic coasts of spain portugal and morocco today these littoral areas areintensely populated and the expected damage could be much greater tsunami studies are of greatimportance in helping to determine the recurrence interval of these events the presence of washover fan deposits on the inland margin of the valdelagrana spit bar cadiz spain indicates the occurrence of a high energy marine event ca 2300 cal yr bp historical geomorphological sedimentological palaeontological and geochronological data suggest that atsunami could have affected the area during roman times copyright 2002 john wiley sons ltd journal of quaternary science keywords tsunami deposits grain size palaeontology gulf of cadiz south spain introduction investigations of the geological records of past tsunamis arean important tool in helping to determine the recurrenceinterval of such events in a region these investigations arealso the only way of determining the prehistoric occurrenceand tsunami hazard in areas of infrequent seismic activity however at present it is dif cult to distinguish betweentsunami deposits and those laid down by other high energyevents such as a storm surge or hurricane recent work bygoff et al 2001 has helped to identify a series of diagnosticcriteria for tsunami deposits and research is underway tohighlight the differences between these and other high energyevents goff and chagu e goff in preparation j goff personalcommunication 2002 wave hydrodynamics the speci ccoastal setting morphology orientation availability and typeof sediments depositional environments tsunami magnitudeand tidal range are all factors that help to de ne the type andpreservation of tsunami deposits furthermore the ability todetermine the tsunamigenic source largely depends upon thepalaeoseismic and historical record e g goff et al 2001

pleistocene coastal stratigraphy sea level highstands and neotectonism of the southern australian passive continental margin a review located in a tectonically stable intraplate setting and in the far field of former ice sheets the southern australian passive continental margin represents a globally important region for quantifying sea level during pleistocene highstands the stratigraphical record of the southern australian margin is dominated by geographically extensive coastal barrier estuarine and peritidal landforms of bioclastic temperate carbonate affinity a function of regional aridity siliciclastic successions dominate the eastern australian coastline despite the generally high level of tectonic stability regional contrasts are evident in the elevation of pleistocene shoreline deposits that largely relate to pre quaternary geotectonic setting the most complete record of pleistocene highstand deposits occurs in the murray basin coorong coastal plain region and indicates that interglacial sea level highstands for at least the past 11 interglacials did not deviate by more than 6 m from present sea level the pleistocene marginal marine record of southern australia is dominantly represented by coastal successions deposited during marine oxygen isotope stages 5e and 7 equating with relative sea level maxima of 2 6 m and greater than 1 m above present sea level apsl respectively intertidal facies of late pleistocene interstadial successions rarely occur above present sea level the most reliable record of glacio eustatic ice equivalent sea level is registered on coastlines developed on stable precambrian cratons such as the gawler craton eyre peninsula where a consistent elevation of 2 m apsl is registered for over 500 km for the last interglacial shoreline 125 ka copyright 2002 john wiley sons ltd

tyrrhenian holocene palaeoclimate trends from spelean serpulids abstract in tropical regions changes in sea level and sea surface temperature sst can be obtained from coral reefs in temperate seas such as the mediterranean where there are neither fossil nor actively growing coral reefs palaeoclimatic trends and associated sea level rise can be reconstructed through radiocarbon ages and the geochemical properties of serpulid calcite tubes from colonies that dwell in submerged caves in the present work we reconstructed holocene palaeoclimate trends for the tyrrhenian sea through the oxygen isotopic composition of marine polychaete serpulids that colonised continental speleothems when the sea invaded the caves which open along the italian coast the long term 18 o trend extracted from multiple serpulid skeletons of 0 7 per mil increase over the last 8 kyr can be interpreted in terms of temperature change but could also be due to long term changes in the salinity balance of the mediterranean if the 18 o trends recorded by serpulid calcite reflected changes in mediterranean sst starting at 8200 cal yr bp it would coincide with the cooling trend recorded in the tropics and in greenland ice cores spelean serpulids radiocarbon ages allowed us to reconstruct a tyrrhenian sea level curve comparable to that recorded along the french mediterranean coast spelean serpulid calcite therefore can be used as a useful tool to reconstruct paleoclimate and sea level changes in temperate coastal karst regions

how long and how stable was the last interglacial abstract surface ocean indicators in the north atlantic during marine isotope stage mis 5 correlate closely with the vegetational succession in northeastern france the melisey i silty layer which marks the end of the last interglacial biozone in la grande pile pollen record appears coeval with the polar front advance c24 registered in the core v29 191 by a sharply increased presence of ice rafted detritus and the cold water foraminifer neogloboquadrina pachyderma sinistral since this event is younger than the peak of mis 5d the last interglacial as recognized in northern france correlates not only with the mis 5e but also with a substantial part of mis 5d the last interglacial in la grande pile was twice as long as the holocene and the climate in its first half was apparently not less stable than during the current interglacial if the future natural climates were to develop as analogs of the past then the onset of the next glacial environments on land would be still many millennia ahead

holocene uplift rates and historical rapid sea level changes at the gargano promontory italy this paper uses a combination of geomorphological and radiometric data from the northern coast of the gargano promontory comprising the fortore river coastal plain and punta delle pietre nere to reconstruct holocene uplift rates the coastal plain consists of a sandy progradational beach sequence that extends seawards from the base of a relict cliff this cliff probably marks the maximum position reached by the holocene transgression altimetric data compared with the age of beach deposits and the available eustatic sea level curves indicate an average holocene uplift rate of 1 5 mm yr 1 a similar uplift rate has been estimated by dating a bioherm constituted of calcareous algae vermetids and subordinately by cladocora caespitosa l which crops out in the locality of punta delle pietre nere this deposit which was previously assigned an interglacial age yielded a mid holocene age by means of th u and 14c age determinations our observations also reveal evidence for coseismic deformation along the northern coast of the gargano promontory during the last millennium vertical displacements of 0 5 m have affected the punta delle pietre nere coastal block and were preceded by periods of slow coastal subsidence which increased rapidly shortly before a major earthquake copyright 2002 john wiley sons ltd

cross barrier flow during orographic precipitation events results from map and improve abstract ground based and airborne doppler radar data collected during passage of frontal rainstorms over the european alps and cascade mountains of oregon are found to exhibit characteristic cross barrier flow and precipitation patterns a stably stratified layer of blocked or partially blocked low momentum flow below mountain crest level is separated from strong cross barrier flow aloft by a concentrated layer of vertical wind shear this shear layer slopes upward toward the mountain crest and persists for several hours as the storm passes over the mountain range this pattern is remarkably similar from case to case and from one mountain range to the other the orographically enhanced precipitation in these cases exhibits stratiform structure marked by a radar bright band which often drops to a lower height indicating locally cooler conditions immediately adjacent to the windward mountain slopes a terrain induced gravity wave produces strong downslope flow and spillover of precipitation onto the

porcelaneous cement and microporosity in california miocene turbidites origin and effect on reservoir properties abstract southern california miocene sands are cemented with porcelaneous cement a mixture of opal a opal ct microquartz and montmorillonite clay this cement was observed filling interparticle pore space in sandstones from the beta and wilmington fields in the los angeles basin the silica minerals result from recrystallization of siliceous organisms such as diatom frustules and sponge spicules which are incorporated into the turbidite sands the montmorillonite sources include detrital clay and alteration of unstable grains about 70 of the bulk volume of the cement is micropore space this microporosity constitutes from one fifth to four fifths of the total porosity in these sandstones rocks with large amounts of microporosity have low permeabilities since fluid flow through the micropore system is restricted recrystallization of the porcelaneous cement with further burial would result in a chert cemented sandstone it is suggested that biogenic silica may be one source of chert cements observed in ancient turbidites

sierra barrier jets atmospheric rivers and precipitation characteristics in northern california a composite perspective based on a network of wind profilers abstractfive 915 mhz wind profilers and gps receivers across california s northern central valley cv and adjacent sierra foothills and coastal zone in tandem with a 6 km resolution gridded reanalysis dataset generated from the weather research and forecasting model document key spatiotemporal characteristics of sierra barrier jets sbjs landfalling atmospheric rivers ars and their interactions composite kinematic and thermodynamic analyses are based on the 13 strongest sbj cases observed by the sloughhouse profiler between 2009 and 2011 the analyses show shallow cool south southeasterly i e sierra parallel flow and associated water vapor transport strengthening with time early in the 24 h compositing period culminating in an sbj core at 1 km above ground over the eastern cv the sbj core increases in altitude up the sierra s windward slope and poleward toward the north end of the cv but it does not reach the westernmost cv above the developing sbj strengthening southwesterly flow des

high precision u series dating of last interglacial events by mass spectrometry houtman abrolhos islands western australia the houtman abrolhos islands situated at the western passive margin of the australian continent consist of a series of shelf edge coral reefs the central platforms of the reefs are late pleistocene in age and are generally some 3 5 m above present sea level the uppermost part of the last interglacial reefs normally has an upward shallowing sequence consisting of coral framestone coralline algal bindstone and skeletal grainstone to rudstone this sequence represents deposition in water depths of less than 2 m and provides a good indicator of sea level high precision mass spectrometric dates of corals from the abrolhos reefs including dates obtained from drill cores arological isotopic and stratigraphic criteria are established for the selection of suitable samples for dating and for assessing the reliability of dates using the screened dates and the stratigraphic evidence the timing and character of the sea level variations of the last interglacial in the abrolhos region are examined the data show that sea level of the last interglacial in the abrolhos was 4 m below its present height by ca 134 ka bp and probably reached about 2 m above present height at ca 133 ka bp the exact time at which sea level reached its peak 6 m above present sea level cannot be determined from our data but it is clear that the sea level high stand of the last interglacial lasted until ca 116 ka bp and that for much of the last interglacial sea level at the abrolhos was at a height of about 4 m above its present level

mesoscale circulations initiated by melting snow a linearized model is used to examine the dynamical effects of a mesoscale temperature perturbation in the lower troposphere the perturbation is a result of nonuniform cooling of the environment by melting snow an organized mesoscale thermal circulation develops with strong vertical motions in the interior outflow at low levels and a return flow at upper levels this circulation is similar to a sea breeze circulation but is forced by an elevated horizontal temperature gradient a possible application to the problem of observed enhanced precipitation regions near a rain snow boundary is considered

large boulder accumulations by extreme waves along the adriatic coast of southern apulia italy abstract the adriatic coast of southern apulia italy is marked by the presence of large boulder accumulations boulders are up to 8 t in weight and arranged either in small groups or rows composed of a few imbricated elements the lower surface of some of the boulders is covered by biogenic encrustation which suggests that they were possibly carved from the mid or sublittoral zone and that they capsized during their transport other boulders detached from the supratidal zone have their surface affected by tilted rock pools new horizontal solution pans are continually forming a detailed survey of a large boulder accumulation was carried out at torre santa sabina direct observations were also made concerning the carving out and transportation of one single boulder during the severe storms in that area on january 4th 2002 and on january 12th 2003 collated data from both the survey and the direct observations including some radiocarbon age determinations and hydrodynamic calculations suggest that the studied accumulation was due to the superimposed effects of one or two tsunami as well as of storm waves tsunami would be responsible for the detachment and transportation of the largest boulders while storm waves may have been responsible for the carving out and transportation of the newer smaller blocks and for moving once again the largest boulders it was in this way that a typical boulder accumulation was produced the collated data suggest that two tsunami may have recently struck the adriatic coast of southern apulia the first possibly took place on the dalmatian coast as a result of the earthquake on april 6 1667 which destroyed ragusa modern day dubrovnik the second tsunami would have accompanied the strong earthquake which took place in southern apulia on february 20 1743

the holocene storegga slide tsunami in the united kingdom all currently known sites in the united kingdom with evidence for the holocene storegga slide tsunami are described information on the altitude distribution stratigraphical context age particle size profile and microfossil characteristics of the deposits is presented the tsunami involved a greater area than previously described reaching a coastline over 600 km long the ubiquitous sand layer which forms the main deposit associated with the event is shown to exhibit a consistent morphology and a particle size profile marked by fining upwards sequences an analysis of new and previously published radiocarbon dates indicates that from evidence in the united kingdom the event took place sometime around 7100 radiocarbon years bp 7900 calibrated years bp a new isobase model for mainland scotland and adjacent areas providing a preliminary estimate of land uplift since the tsunami is presented the model estimates contemporary sea surface level offshore at 14 m below the present day mean high water spring tides tsunami sediment run up is greatest in inlets where it reaches at least 25 m on shetland and at least 5 m along the mainland coastline to the south and run up of the tsunami would have exceeded these values the tsunami sediments identified here are considered particularly valuable as a synchronous marker horizon

duration and structure of the past four interglaciations reanalysis and additional dating of the devils hole 18o paleotemperature record confirm that the last interglaciation in the great basin the continental analog of marine isotopic substage 5e lasted 22 000 yr consistent with the vostok paleotemperature record which suggests a duration of 19 000 yr for this event in antarctica the three preceding interglaciations in the devils hole record analogs of marine isotopic substages 7e 9c and 11c range from 20 000 to 26 000 yr in duration a 20 000 yr duration for the last interglaciation is consistent with tims uranium series dated sea level high stands thus the widely held view that interglaciations were of 11 000 to 13 000 yr duration and constituted only about 10 of mid to late pleistocene climatic cycles needs reexamination the warmest portion of each interglaciation in the devils hole time series is marked by a 18o plateau signifying apparent climatic stability for periods of 10 000 to 15 000 yr duration

kinematic and thermodynamic structures of sierra barrier jets and overrunning atmospheric rivers during a landfalling winter storm in northern california abstractthis study characterizes kinematic and thermodynamic structures of sierra barrier jets sbjs atmospheric rivers ars and their interaction over the period 14 16 february 2011 when a winter storm made landfall in northern california a suite of scanning and profiling doppler radars rawinsondes and gps receivers is used to document these structures across the central valley and up the western sierra slope to the crest along an 200 km segment of the sierra the winter storm is grouped into two episodes each having an ar that made landfall low level winds in the sbj observed during episode 1 were southeasterly and embedded in a stably stratified air mass along barrier wind speeds u340 reached maximum values of 25 30 m s 1 as low as 0 2 km msl over the central valley and as high as 1 5 km msl over the western sierra slope southwesterly winds associated with the ar overlaid the sbj along an interface that sloped upward from southwest to northeast with a southwestern extent at the western

microporosity development in shallow marine sediments from the nankai trough abstract i characterized microporosity by performing low pressure nitrogen adsorption measurements on 13 shallow marine mudstone samples from the nankai trough offshore japan the samples were from two reference sites on the incoming philippine sea plate and one site above the accretionary prism i determined pore size distributions using the barrett joyner hallenda bjh model and merged these with existing mercury injection capillary pressure micp measurements to construct a full distribution covering micro to macropores i found that overall pore sizes decrease with consolidation and that microporosity content pores ca 2 sr si show inconsistent relationships with microporosity development and cannot confirm or deny the role of ash alteration in this process the strongest correlation observed at the three sites was between microporosity volume and clay mineral fraction this suggests that microporosity content is determined mainly by detrital clay abundance and development of clay as an ash alteration product with some contribution from amorphous silica cement precipitated in the zones of anomalous high porosity

linearly stratified rotating flow over long ridges in a channel the flow of a rotating linearly stratified fluid over a long symmetric ridge in a channel is investigated experimentally the laboratory apparatus consists of a long channel of rectangular cross section the upper bounding surface is a transparent horizontal plane the lower boundary is a horizontal flexible belt the belt serves as a false bottom of the channel and is translated parallel to its long axis topographic features are mounted on the belt and are towed through a salt stratified fluid which is otherwise at rest relative to a rotating observer the channel rests on a rotating table whose rotation axis is vertical the most important dimensionless parameters governing the motion are the rossby and ekman numbers a stratification parameter defined as the ratio of the brunt vaisala frequency to the coriolis parameter and the geometrical parameters defining the aspect ratio of the ridge the ridge height to channel depth ratio and the ridge to channel width ratios an analysis is presented that demonstrates the conditions under which centrifugal effects can be neglected in such laboratory experiments the analysis also shows the conditions under which the laboratory flows should be a good approximation to the quasigeostrophic potential vorticity equations and attendant boundary conditions for the oceans and atmosphere this analysis is made for a general three dimensional topographic feature i e it is not restricted to a long ridge the laboratory system seems to be an excellent vehicle for modelling oceanic flows but does not properly reproduce a non boussinesq term in the atmospheric equation an analysis for an infinitely long ridge is presented the predictions so obtained are in good qualitative agreement with the experiments the quantitative agreement for the range of parameters considered however is shown to be poor and this is attributed to neglecting the effects of the lateral bounding surfaces the experiments demonstrate that for fixed rotation stratification and free stream speed the streakline deflection caused by the topography decays with height for such experiments the flow in the lower levels for positive upward rotation deflects to the left before reaching the ridge then continues to deflect to the left on the upwind side of the ridge before beginning a rightward drift slightly upstream of the mountain crest this rightward drift continues on the downwind side of the ridge and well downstream of the ridge itself before reaching a maximum shift from which a leftward drift again begins increased rotation other parameters being held fixed provides stronger horizontal streakline deflections stronger stratification other parameters being fixed leads to stronger downslope winds and possibly flow separation in the lee various characteristics of the flow field such as the distance upstream to which substantial streakline curvature is observed are measured as functions of the various system parameters comparisons with the infinite ridge theory are also made the downstream motion is accompanied by lee waves for the major portion of the parameter space examined the amplitude of these waves is shown to decrease with increased rotation other parameters being held fixed some non rotating experiments are conducted and these are shown to be in good agreement with the model of long 1955 and the measured wavelengths are found to be in good agreement with linear theory and laboratory measurements made by other investigators measurements supporting the theory of queney 1947 are presented which show that the horizontal wavelengths of the lee waves decrease for increased rotation other parameters being fixed a flow regime map based on the observed structure of the vertical wave motion is developed and it is shown that for the range of parameters considered rotation plays only a minor role if any

reply to the comment of pedoja et al by maouche s meghraoui m morhange c belabbes s bouhadad y and haddoum h on the published paper maouche s meghraoui m morhange c belabbes s bouhadad y and haddoum h 2011 active coastal thrusting and folding and uplift rate of the sahel anticline and zemmouri earthquake area tell atlas algeria tectonophysics 509 2011 69 80 reply to the comment of pedoja et al by maouche s meghraoui m morhange c belabbes s bouhadad y and haddoum h on the published paper maouche s meghraoui m morhange c belabbes s bouhadad y and haddoum h 2011 active coastal thrusting and folding and uplift rate of the sahel anticline and zemmouri earthquake area tell atlas algeria tectonophysics 509 2011 69 80 said maouche mustapha meghraoui christophe morhange samir belabbes youcef bouhadad hamid haddoum

late holocene tsunamogenic coseismic uplift in kerkira island greece the presence of a coralligenic like bioherm constituted by boulders up to 1 2 m in diameter cemented by bioconcretions of calcareous algae and vermetids spp has been recognized in the southernmost part of kerkira island this biostructure is placed at up to 1 4 m above the present mean sea level a few hundred meters north well developed beach rocks are at about the same elevation the morphological continuity of these landforms allows us to hypothesize that a recent coseismic uplift interested this area ams age determination has been performed on different vermetids sampled in the upper part of the raised bioherm moreover a complete review of the chronological data cited in the bibliography highlights the difficulties in the use of some bioindicators as chronologically precise sea level indicators the entire data set suggests a late holocene tectonic behaviour characterized by sequences of subsidence and coseismic uplift in particular the age of the raised bioherm suggests that a coseismic uplift occurred 3 ka bp due to an earthquake of regional interest capable of generating a strong tsunami that impacted the nearest coast of lefkada island and the plaghia peninsula

notes and correspondence polarimetric radar observation of multiple freezing levels abstract an unusual multiple freezing level event observed with polarimetric radar during the second phase of the improvement of microphysical parameterization through observational verification experiments improve 2 field program is described the event occurred on 28 november 2001 when a warm front moved over the oregon cascade mountains as the front approached an elevated melting layer formed above a preexisting melting layer near ground continued warming of the lower atmosphere eventually dissipated the lower melting layer the polarimetric measurements are used to estimate the height of the freezing levels document their evolution and deduce hydrometeor habits the measurements indicate that when the two freezing levels were first observed melting was incomplete in the upper melting layer and characteristics of particles that passed through the two melting layers were similar as warming progressed the character of particles entering the lower melting layer changed possibly becoming ice pell

interstadial coral reef terraces and relative sea level changes during marine oxygen isotope stages 3 4 kikai island central ryukyus japan abstract coral reef terraces are one of the best recorders of relative sea level changes during the last glacial cycle thus far knowledge of relative sea level record based on coral reefs during the marine oxygen isotope stage ois 3 has been limited to studies of the huon peninsula papua new guinea high precision a spectrometric 230 th 234 u dating demonstrated an offlapping sequence of five coral reef complexes ages of which are 66 64 62 55 and 52 ka in the northern part of kikai island central ryukyus of japan interstadial reefs characterized by deepening upward sequences of coral assemblages recorded three hemicycles from transgression to highstand at 52 62 and 66 ka during which these reefs were drowned these highstands in the relative sea level record can be correlated with the eustatic record reconstructed from the huon reef terraces and with the interstadials 14 18 and 19 of the gisp 2 oxygen isotope record this consistency confirms the huon sea level record of ois 3 and implies that the eustatic sea level responded to the millennial scale climate changes even during the glacial period of ois 4

orographic effects on precipitating clouds 1 precipitation over and near mountains is not caused by topography but rather occurs when storms of a type that can occur anywhere deep convection fronts tropical cyclones form near or move over complex terrain deep convective systems occurring near mountains are affected by channeling of airflow near mountains capping of moist boundary layers by flow subsiding from higher terrain and triggering to break the cap when low level flow encounters hills near the bases of major mountain ranges mesoscale convective systems are triggered by nocturnal downslope flows and by diurnally triggered disturbances propagating away from mountain ranges the stratiform regions of mesoscale convective systems are enhanced by upslope flow when they move over mountains in frontal cloud systems the poleward flow of warm sector air ahead of the system may rise easily over terrain and a maximum of precipitating cloud occurs over the first rise of terrain and rainfall is maximum on ridges and minimum in valleys if the low level air ahead of the system is stable blocking or damming occurs shear between a blocked layer and unblocked moist air above favors turbulent overturning which can accelerate precipitation fallout in tropical cyclones the tangential winds encountering a mountain range produce a gravity wave response and greatly enhanced upslope flow depending on the height of the mountain the maximum rain may occur on either the windward or leeward side when the capped boundary layer of the eye of a tropical cyclone passes over a mountain the cap may be broken with intense convection resulting

late quaternary relative sea level changes and vertical movements at lipari aeolian islands indicators of former sea levels are recognised on the emergent portion of lipari aeolian islands they correlate with three raised shorelines located at elevations of 43 45 m above present sea level i 23 27 m ii and about 12 m iii according to stratigraphical constraints these shorelines correlate with the sea level highstands corresponding to marine oxygen isotope substages 5e 124 ka 5c 100 ka and 5a 81 ka respectively the correlation of the shoreline i with substage 5e is supported by a u th age 119 6 ka obtained from corals chronological and height data relevant to the fossil shorelines indicate that lipari was affected by uplift with an average rate of 0 34 mm yr 1 during the past 125 ka this uplift rate accords with the average uplift rates obtained during the same time period from the nearby islands of filicudi 0 31 mm yr 1 and salina 0 36 mm yr 1 combined these data suggest a similar uplift trend related to regional tectonic processes in contrast to the long term uplift a localised submergence trend documented especially for the last century affects the eastern coast of lipari this subsidence is related to neo and or volcano tectonic processes copyright 2002 john wiley sons ltd

eustatic and tectonic control on late quaternary alluvial fans along the tyrrhenian sea coast of calabria south italy abstract the late quaternary evolution of the western coastal range northern calabria has been reconstructed by means of a multidisciplinary approach we have focused on the role of allocyclic mechanisms tectonics and base level change considered as factors influencing alluvial fan development in particular we identify no clear evidence for a major influence of climate age constraints were provided by a tephra layer and a paleosol coupled with geomorphological correlations middle pleistocene perched terraces and fan relicts hanging above fault scarps indicate that tectonics caused switches in fan dynamics between aggradational and erosional phases as tectonic activity declined during late middle pleistocene eustatically driven changes in base level possibly plus low rates of tectonic subsidence represent the main factor which controlled late pleistocene fan development the two major fan aggradation phases occurred during periods of climate amelioration prior to highstands whereas high sea levels ois 5 and 1 promoted channel incision into the fan surfaces this continued during periods of climate deterioration with a seaward progradation of alluvial deposition sea level rise is seen as creating accommodation space producing very open fans locally within mountain embayments the fans are characterised by a mushroom shape in plan view and by a retrograde stacking pattern of alluvial fan facies

holocene coastal uplift in the western pacific rim in the context of late quaternary uplift abstract this paper reviews recent studies of holocene coastal uplift in tectonically active areas near the plate boundaries of the western pacific rim emergent holocene terraces exist along the coast of north island of new zealand the huon peninsula of papua new guinea the japanese islands and taiwan these terraces have several features in common all comprise series of subdivided terraces the highest terrace is a constructional terrace underlain by estuarine or marine deposits and the lower terraces are erosional cutting into transgressive deposits or bedrock the highest terrace records the culmination of holocene sea level rise at ca 6 6 5 ka bp lower terraces were coseismically uplifted repeated major earthquakes have usually occurred at ka intervals and meter scale uplift the maximum uplift rate and number of terraces are surprisingly similar about 4 m ka and seven to four major steps in north island huon peninsula and japan taiwan especially along the east coast of the coastal range is different reaching a maximum uplift rate of 15 m ka with 10 subdivided steps they record a very rapid uplift comparison between short term holocene and long term since the last interglacial maximum sub stage 5e uplift rates demonstrates that a steady uplift rate huon peninsula or accelerated uplift toward the present several areas of japan and north island has continued at least since isotope sub stage 5e rapid uplift in eastern taiwan probably started only in the early holocene judging from the absence of any older marine terraces most of the causative faults for the coastal uplift may be offshore reverse faults branched from the main plate boundary fault but some of them are onshore faults which deformed progressively with time

a tsunami ca 6300 years bp and other holocene environmental changes northern hawke s bay new zealand abstract sediment cores collected in a coastal lagoon a few kilometres east of wairoa northern hawke s bay new zealand were examined using sedimentological geochemical palynological and micropaleontological analyses a distinct short lived catastrophic saltwater inundation csi about 6300 years bp and possibly other minor marine incursions are preserved in the coastal estuarine to lagoonal freshwater sedimentary sequences which have been deposited in the last 6500 years the csi is characterised by a gravel unit that thins landward and decreases in particle size to sand within a sequence consisting mainly of brackish estuarine muds diatom assemblages indicate a marked change from the shallow brackish estuarine muds to marine gravels and sands to brackish estuarine muds the marine influence in the gravel and sand is also shown by the presence of marine dinoflagellates and a peak in na rb sedimentological chemical and paleontological in particular diatoms evidence indicates it is a csi we conclude that this was a tsunami and propose the most likely propagating mechanisms marine influence decreases upcore and totally freshwater conditions are evident in the upper section of the cores the geochemistry of the sediments mainly reflects the change in stratigraphy with distinct signatures for tephra na fe cr organic rich and peat units as br and the coarse gravel sand csi unit na rb cr fe but it is also indicative of changes in depositional environment the change in chemistry na rb in the csi event is indicative of a saltwater influence whereas a marked change in s content suggests a sudden change from brackish to freshwater conditions shortly after 4800 years bp another peak in s and br content about 3200 years bp may indicate another temporary change to brackish conditions

orographic precipitation forcing along the coast of northern california during a landfalling winter storm abstractthis study documents orographic precipitation forcing along the coastal mountains of northern california during the landfall of a significant winter storm over the period 16 18 february 2004 the primary observing asset is a scanning x band doppler radar deployed on the coast at fort ross california which provides low level e g below 1 km msl horizontal and vertical scans of radial velocity and reflectivity to characterize airflow and precipitation structures further context is provided by a wind profiling radar a radio acoustic sounding system rass balloon soundings buoys a gps receiver and surface meteorological sensors the winter storm is divided into two episodes each having pre cold frontal low level jet llj structures and atmospheric river characteristics episode 1 has a corridor of terrain trapped airflow tta that forms an interface with the llj the interface extends 25 km offshore in a 0 5 km vertical layer and the western edge of this interface near the ocean surf

contemporary and fossil foraminifera from isolation basins in northwest scotland isolation basins are widely used in sea level reconstructions but contemporary analogues have been poorly studied comparatively recent research has identified isolation basins with extended transitional isolation contacts that pose problems in sea level interpretations this paper presents foraminiferal results from 24 contemporary isolation basins combined with data from two isolation basins with extended isolation contacts foraminiferal associations identified from the contemporary basins show a clear relationship with water salinity and sill altitude that supports interpretation of the extended fossil sequences an association dominated by miliammina fusca mf signifies a basin close to final isolation from marine influence increasing marine inundation of basins is signified by a series of associations dominated by the following foraminifera ja jadammina macrescens and m fusca me m fusca and elphidium williamsoni ew e williamsoni he haynesina germanica and e williamsoni nd nonion depressulus these associations can be used to interpret the sedimentary isolation sequences from loch nan corr and rumach vi a pilot study of the stable isotope signature from the two species h germanica and e williamsoni is reported from rumach vi and loch nan corr the results show the potential of stable isotope analysis for environmental reconstruction from isolation basins in particular using 18o for salinity reconstruction

comparison of esr and tims u th dating of marine isotope stage mis 5e 5c and 5a coral from barbados implications for palaeo sea level changes in the caribbean abstract electron spin resonance esr dating of coral has become an efficient geochronological tool in supporting morphostratigraphic studies carried out on barbados during the last 10 years the newly developed approach for de determination de dmax plot procedure improves the precision of esr dating of pleistocene coral and therefore permits differentiation between the main marine isotope stages mis 5 7 9 and 11 and also between sub stages 5e c and a this study compares results of esr and tims uranium series dating u th of emergent last interglacial coral reef terraces from barbados and presents some implications for the timing and extent of sea level changes during marine isotope stages mis 5e c and a both dating methods indicate a distinct formation of up to three coral reef terraces during mis 5e at approximately 132 ka esr to 128 ka u th at c 128 ka esr and at c 120 ka u th to 118 ka esr it is also highly probable that three reef terraces were developed during mis 5c between c 103 ka u th and 105 ka esr the formation of two separate coral reefs during mis 5a is recognized for the first time on barbados with an age estimate for the older mis 5a 2 reef of 85 ka esr or 84 ka u th and an age estimate for the younger mis 5a 1 reef terraces of 74 ka esr or 77 ka u th assuming a constant uplift rate of 0 276 m ka at the south coast of barbados sea level reached its maximum during mis 5e 3 and mis 5e 2 between 132 and 128 ka ago after this sea level declined reaching a level of c 11 m below present sea level approx 118 120 ka ago mis 5e 1 during the substage 5c sea level was generally lower than in substage 5e it reached relative maxima at c 13 20 and 25 m during mis 5c approx 105 ka and formed three distinct coral reef terraces probably in relative short time intervals for the first time a double sea level oscillation is recognized on barbados during mis 5a an early mis 5a 2 c 85 ka with a sea level places at approx 21 m and a late mis 5a 1 sub stage c 74 or 77 ka with a sea level at approx 19 m below present sea level

holocene land and sea level changes in great britain analysis of more than 1200 radiocarbon dated samples that constrain relative sea levels in great britain over the past 16 000 yr provides estimates of current land level changes negative of relative sea level change maximum relative land uplift occurs in central and western scotland ca 1 6 mm yr 1 and maximum subsidence is in southwest england ca 1 2 mm yr 1 sediment consolidation arising from autocompaction as the sediment accumulates and from land drainage increases the subsidence in areas with thick sequences of holocene sediments with an average effect equivalent to at least an extra ca 0 2 mm yr 1 land subsidence but more in parts of southeast england 0 5 1 1 mm yr 1 modelled changes in tidal range during the mid to late holocene in eastern england suggest that the calculated rate of land subsidence is overestimated unless such changes are quantified the effect is most significant for large coastal lowlands the fenland and humber ca 0 5 and 0 6 mm yr 1 that were tidal embayments during the mid to late holocene

damaging southerly winds caused by barrier jets in the cook strait and wellington region of new zealand abstractstrong southerly winds regularly occur in the cook strait region of new zealand occasionally these winds are strong enough to cause severe damage to property and threaten human life one example of a storm containing such winds is the wellington storm which occurred on 20 june 2013 for this case wind speeds in cook strait were stronger than those observed or forecast elsewhere in the storm even though wind speeds of this intensity are rare storms affecting new zealand with central pressures equal to the wellington storm 976 hpa are not uncommon numerical experiments have been carried out to investigate the possible reasons for the exceptional damaging southerly winds dsws occurring in this storm analyses of the simulations showed that dsws in cook strait for this event were actually barrier jets not gap winds as they appeared the strength of barrier jets in cook strait is sensitive to the precise location of the storm center this explains the uncommon occurrence of dsws in cook

reconciliation of late quaternary sea levels derived from coral terraces at huon peninsula with deep sea oxygen isotope records a major discrepancy between the late quaternary sea level changes derived from raised coral reef terraces at the huon peninsula in papua new guinea and from oxygen isotopes in deep sea cores is resolved the two methods agree closely from 120 ka to 80 ka and from 20 ka to 0 ka ka 1000 yr before present but between 70 and 30 ka the isotopic sea levels are 20 40 m lower than the huon peninsula sea levels derived in earlier studies new high precision u series age measurements and revised stratigraphic data for huon peninsula terraces aged between 30 and 70 ka now give similar sea levels to those based on deep sea oxygen isotope data planktonic and benthic 18o data using the sea level and deep sea isotopic data oxygen isotope ratios are calculated for the northern continental ice sheets through the last glacial cycle and are consistent with results from greenland ice cores the record of ice volume changes through the last glacial cycle now appears to be reasonably complete