dwindling groundwater resources in northern india from satellite gravity observations 1 northern india and its surroundings home to roughly 600 million people is probably the most heavily irrigated region in the world temporal changes in earth s gravity field in this region as recorded by the grace satellite mission reveal a steady large scale mass loss that we attribute to excessive extraction of groundwater combining the grace data with hydrological models to remove natural variability we conclude the region lost groundwater at a rate of 54 9 km3 yr between april 2002 the start of the grace mission and june 2008 this is probably the largest rate of groundwater loss in any comparable sized region on earth its likely contribution to sea level rise is roughly equivalent to that from melting alaskan glaciers this trend if sustained will lead to a major water crisis in this region when this non renewable resource is exhausted

post processing removal of correlated errors in grace data 1 gravity fields produced by the gravity recovery and climate experiment grace satellite mission require smoothing to reduce the effects of errors present in short wavelength components as the smoothing radius decreases these errors manifest themselves in maps of surface mass variability as long linear features generally oriented north to south i e stripes the presence of stripes implies correlations in the gravity field coefficients here we examine the spectral signature of these correlated errors and present a method to remove them finally we apply the filter to a model of surface mass variability to show that the filter has relatively little degradation of the underlying geophysical signals we seek to recover

directional wave measurement at haifa israel and sediment transport along the nile littoral cell abstract results of three years of directional wave measurement at the eastern mediterranean coast of haifa israel are presented the wave height and energy flux distributions reveal a moderately high energy coast with a bimodal annual cycle the rate of wave induced longshore sediment transport is estimated from the directional energy flux distributions it describes an annual cycle with a maximum northward transport of 75 14 10 3 m 3 month in midwinter and a southward transport of 26 5 10 3 m 3 month in summer the net annual transport is northward and computed at 110 100 10 3 m 3 yr we show that a wave induced transport is sufficient in explaining the apparent transport of sediments in the nile littoral cell from the nile delta source to the haifa bay sink

short and long term erosional processes affecting the stability of the mediterranean coastal cliffs of israel abstract the destructive processes affecting the coastal cliffs of israel are seen as time dependent processes acting in two independent zones at the top and bottom of the cliffs at the top of the cliff these processes are classed as short term phenomena that may be seen as seasonal changes or those initiated by man two main phenomena are recognized as multiple sliding at the contact of hamra clay and kurkar sandstone horizons and collapse of an overlying hard calcarenite layer high water content is by far the most significant contributor to instability which is aggravated by excessive watering of gardens near the cliff edge other factors contributing to instability are grain size and lack of cementation at the bottom of the cliff these processes are classed as long term phenomena where several climatic seasons to a number of years may pass between events these processes are mainly dependent on the abrasive action of waves and to a lesser extent on wind stability is dependent on factors such as grain size distribution of particles cross bedding and degree of cementation of the sandstone the factor of safety f for kurkar slopes ranges from f 1 29 1 78 and that of hamra slopes from f 0 59 0 60 recognition of the active processes causing instability in the different parts of the cliffs and the factors controlling them is essential for the design and remedial measures required for controlling the continued destruction of the cliffs

sediment flux dynamics over the shallow 25 m depth shelf of the mediterranean sea along the israeli coast abstract in order to study the dynamics of sediment fluxes at the northern end of the nile littoral cell sediment traps were deployed for one year over the shallow shelf of the mediterranean sea offshore israel the sediment traps replaced monthly were suspended on a mooring line two kilometers offshore of the hadera power station 10 m above a 25 m deep seafloor sea state conditions near the traps were measured by an acoustic doppler profiler that provided the bottom water temperature wave heights and current s velocities and direction the measured sediment fluxes greatly varied between sampling periods with a minimum value of 1 8 g m 2 d 1 in autumn and a maximum value of 83 g m 2 d 1 in winter this variation was mostly effected by wave induced resuspension of sediment a strong correlation r2 0 97 was found between integrated wave heights that exceeded 1 5 m and the measured sediment fluxes based on the sea state conditions and sediment trap data we conclude that the direction of sand transport at the study area was strictly northwards and that almost all of the annual sand transport occurred during several high energy events in the winter fine particles that consisted the majority of the mass flux were absent in the underlying 25 m deep seafloor suggesting that they are very effectively winnowed off beyond the sand strip

the role of detrital anhydrite in diagenesis of aeolian sandstones upper rotliegend the netherlands implications for reservoir quality prediction the rotliegend upper permian reservoir interval in the southern permian basin spb contains low permeability streaks corresponding to anhydrite cemented intervals an integrated study was conducted using core cuttings thin sections and well log data from a gas exploration well and two geothermal wells that target the zone of interest this study aims at understanding the origin and nature of these low permeability streaks as well as their impact on reservoir properties and to establish a predictive model of their spatial distribution high resolution xrf core scanning analysis allowed to extrapolate spot observations in thin sections to the entire core diagenetic history includes grain rearrangement and anhydrite haematitic clay coatings dolomite rims quartz overgrowths kaolinite and second generation carbonates as cementing phases coupling of all data reveals the detrital origin of the anhydrite gypsum grains which were deposited together with the coarse grained sand fraction in an aeolian sandflat environment such partially or completely dissolved grains acted as local sources of anhydrite cement and as nuclei for precipitation explaining its preferential occurrence in coarsegrained laminae thick gypscretes in the vicinity likely supplied the anhydrite gypsum grains a conceptual model is proposed including the location of nearby gypscretes and the prevailing west southwest aeolian transport direction on the southern rim of the spb

decadal scale coastal cliff retreat in southern and central california abstract airborne lidar data collected in 1998 and 2009 2010 were used to measure coastal cliff erosion and retreat between the mexico california border and bodega head california cliff erosion was detected along 44 of the 595 km of shoreline evaluated while the remaining cliffs were relatively stable the mean cliff top retreat rate was 0 12 m yr while mean retreat averaged over the entire cliff face was 0 04 m yr the maximum cliff top and face retreat rates were 4 2 and 3 8 m yr respectively historical 1930s to 1998 and recent retreat rates were significantly inversely correlated for areas with large historical or recent cliff retreat such that locations with elevated historical retreat had low levels of recent retreat and locations with elevated recent retreat were preceded by low rates of historical retreat the strength of this inverse correlation increased with cliff change magnitudes up to r2 of 0 91 for cliff top retreat rates 2 9 m yr mean recent retreat rates were 52 83 lower than mean historical retreat rates although beaches can protect cliffs against wave driven erosion cliffs fronted by beaches retreated 49 more than cliffs without beaches on average unarmored cliff faces retreated 0 05 m yr between 1998 and 2009 2010 about three times faster than artificially armored cliffs alongshore metrics of wave cliff impact precipitation and cliff hardness were generally not well correlated with recent cliff changes a cliff hazard metric is used to detect cliff steepening and areas prone to future cliff top failures

inference of mantle viscosity from grace and relative sea level data summary gravity recovery and climate experiment grace satellite observations of secular changes in gravity near hudson bay and geological measurements of relative sea level rsl changes over the last 10 000 yr in the same region are used in a monte carlo inversion to infer mantle viscosity structure the grace secular change in gravity shows a significant positive anomaly over a broad region 3000 km near hudson bay with a maximum of 2 5 gal yr 1 slightly west of hudson bay the pattern of this anomaly is remarkably consistent with that predicted for postglacial rebound using the ice 5g deglaciation history strongly suggesting a postglacial rebound origin for the gravity change we find that the grace and rsl data are insensitive to mantle viscosity below 1800 km depth a conclusion similar to that from previous studies that used only rsl data for a mantle with homogeneous viscosity the grace and rsl data require a viscosity between 1 4 1021 and 2 3 1021 pa s an inversion for two mantle viscosity layers separated at a depth of 670 km shows an ensemble of viscosity structures compatible with the data while the lowest misfit occurs for upper and lower mantle viscosities of 5 3 1020 and 2 3 1021 pa s respectively a weaker upper mantle may be compensated by a stronger lower mantle such that there exist other models that also provide a reasonable fit to the data we find that the grace and rsl data used in this study cannot resolve more than two layers in the upper 1800 km of the mantle

longshore sand transport estimates along the mediterranean coast of israel in the holocene abstract the nile littoral cell one of the world s longest runs 650 km along the southeastern mediterranean from abu quir bay near alexandria egypt to haifa bay on the northern israeli coast haifa bay constitutes the northernmost final depositional sink of nile derived quartz sand transported from the nile delta by longshore currents generated by approaching breaking waves the northward net sand transport along the mediterranean coast of israel results from larger waves approaching from west south west and south west compared to their counterparts from west north west and north west this study utilizes an extensive new database gathered from sediment drill cores marine geophysical maps and field observations to measure the volume of sand deposited in haifa bay and the adjacent zevulun plain during the holocene it then compares this volume to recent data including measurements of sand accumulation along haifa port s main breakwater constructed in the southern entrance of the bay as well as longshore sand transport estimates along the northern carmel coast research findings estimate the annual average quantity of sand transported to haifa bay throughout the period at 80 000 90 000 m3 the findings further conclude that this amount has not changed appreciably over the past 75 years evaluating calculated values over the long term it is suggested that the characteristics of longshore sand transport along the coast of israel have not changed significantly during the past 7900 8500 years it is obvious that this conjecture should be treated with reservations

variations of the earth s figure axis from satellite laser ranging and grace 1 satellite laser ranging slr data were used to determine the variations in the earth s principal figure axis represented by the degree 2 and order 1 geopotential coefficients c21 and s21 significant variations at the annual and chandler wobble frequencies appear in the slr time series when the rotational deformation or pole tides i e the solid earth and ocean pole tides were not modeled the contribution of the ocean pole tide is estimated to be only 8 of the total annual variations in the normalized coefficients based on the analysis of slr data the amplitude of the nontidal annual variation of is only 30 of from the slr time series the estimates of the annual variation in from slr the gravity recovery and climate experiment grace and polar motion excitation function are in a good agreement the nature of the linear trend for the earth s figure axis determined by these techniques during the last several years is in general agreement but does not agree as well with results predicted from current glacial isostatic adjustment gia models the fluid love number for the earth is estimated to be 0 9 based on the position of the mean figure axis from the grace gravity model ggm03s and the mean pole defined by the iers 2003 conventions the estimate of from grace and slr provides an improved constraint on the relative rotation of the core the results presented here indicate a possible tilt of the inner core figure axis of 2 and 3 arc sec displacement for the figure axis of the entire core

evaluation of new grace time variable gravity data over the ocean 1 monthly grace gravity field models from the three science processing centers csr gfz and jpl are analyzed for the period from february 2003 to april 2005 over the ocean the data are used to estimate maps of the mass component of sea level at smoothing radii of 500 km and 750 km in addition to using new gravity field models a filter has been applied to estimate and remove systematic errors in the coefficients that cause erroneous patterns in the maps of equivalent water level the filter is described and its effects are discussed the grace maps have been evaluated using a residual analysis with maps of altimeter sea level from jason 1 corrected for steric variations using the world ocean atlas 2001 monthly climatology the mean uncertainty of grace maps determined from an average of data from all 3 processing centers is estimated to be less than 1 8 cm rms at 750 km smoothing and 2 4 cm at 500 km smoothing which is better than was found previously using the first generation grace gravity fields

determining north atlantic meridional transport variability from pressure on the western boundary a model investigation 1 in this paper we investigate the possibility of determining north atlantic meridional transport variability using pressure on the western boundary focusing on the 42 n latitude of the halifax wave array we start by reviewing the theoretical foundations of this approach next we present results from a model analysis both statistical and dynamic that demonstrate the feasibility of the approach we consider how well we can quantify the meridional transport variability at 42 n given complete knowledge of bottom pressure across the basin and to what degree this quantification is degraded by first ignoring the effect of intervening topography and then by using only bottom pressure on the western boundary we find that for periods of greater than 1 year we can recover more than 90 of the variability of the main overturning cell at 42 n using only the western boundary pressure provided that we remove the depth averaged boundary pressure signal this signal arises from a basin mode of bottom pressure variability which has power at all time scales but that does not in truth have a meridional transport signal associated with it and from the geostrophic depth independent compensation of the ekman transport an additional benefit of the removal of the depth averaged pressure is that this high frequency ekman signal which is essentially noise as far as monitoring the meridional overturning circulation for climatically important changes is concerned is clearly separated from other modes

coastal cliff retreat rates at beit yannay israel in the 20th century research indicates that the aeolianite kurkar cliffs along the israeli mediterranean coastline have continuously retreated eastward during the last few decades there seems to be no dispute among earth scientists regarding the general trend of cliff retreat however the majority of papers displaying cliff retreat rates are based upon comparison of aerial photographs their lack of advanced geometric measurement methods causes a high margin of error public attention is focused upon the beit yannay coastal cliff since private homes are located along the southern section of the cliff crest the current research compares the historic location of the cliff crest edge at beit yannay as observed in a series of aerial photographs taken during the period 1918 2000 quantitative measurement methods included applications of satellite geodesy and digital photogrammetry and mapping research results offer quantitative consecutive and highly accurate data regarding retreat rates over a relatively long period of 82 years it is concluded that 1 annual average cliff retreat rates of the cliff crest is 20 cm year 2 categorization of the study time span reveals periods displaying varying retreat rates such as 27 cm year during 1918 1946 21 cm year during 1946 1973 and 10 cm year during 1973 2000 3 maximum retreat distances of the cliff crest over the study period were found to be approximately 25 m along the northern lowest section of the cliff minimum distances of 11 m were identified at the highest southern section of the cliff 4 the eolianite kurkar cliffs along the israeli mediterranean coast throughout the 20th century have been an important source of sediment contributing approximately 24 10 6 m 3 of sediments to the sediment balance of israeli beaches copyright 2004 john wiley sons ltd

improved methods for observing earth s time variable mass distribution with grace using spherical cap mascons we discuss several classes of improvements to gravity solutions from the gravity recovery and climate experiment grace mission these include both improvements in background geophysical models and orbital parameterization leading to the unconstrained spherical harmonic solution jpl rl05 and an alternate jpl rl05m mass concentration mascon solution benefitting from those same improvements but derived in surface spherical cap mascons the mascon basis functions allow for convenient application of a priori information derived from near global geophysical models to prevent striping in the solutions the resulting mass flux solutions are shown to suffer less from leakage errors than harmonic solutions and do not necessitate empirical filters to remove north south stripes lowering the dependence on using scale factors the global mean scale factor decreases by 0 17 to gain accurate mass estimates ocean bottom pressure obp time series derived from the mascon solutions are shown to have greater correlation with in situ data than do spherical harmonic solutions increase in correlation coefficient of 0 08 globally particularly in low latitude regions with small signal power increase in correlation coefficient of 0 35 regionally in addition to reducing the error rms with respect to the in situ data reduction of 0 37 cm globally and as much as 1 cm regionally greenland and antarctica mass balance estimates derived from the mascon solutions agree within formal uncertainties with previously published results computing basin averages for hydrology applications shows general agreement between harmonic and mascon solutions for large basins however mascon solutions typically have greater resolution for smaller spatial regions in particular when studying secular signals

characteristics of sea cliff erosion induced by a strong winter storm in the eastern mediterranean abstract changes in sea cliff morphologies along the 30 km long sharon escarpment segment of israel s weakly cemented mediterranean eolianite cliff line were analyzed to gain quantitative insights into erosion characteristics associated with a high energy winter storm 10 20 year return interval ground based repeat lidar measurements at five sites along the cliff line captured perturbations of cliff stability by basal wave scouring during the storm subsequent post storm gravity driven slope failures in the cliff face above and return of the system to transient stability within several months post storm erosion which amounted to 70 of the total volume of cliff erosion documented resulted in dramatic local effects of up to 8 m of cliff top retreat and yet at the larger scale of the 30 km cliff line examined erosion during the storm and the year that followed affected less than 4 of the cliff length and does not appear to be above the average cliff length annual erosion implied by previously published decadal scale retreat rates along this sea cliff our results do not support a direct association between strong storm events and elevated erosion and retreat at the cliff line scale

time variability of the earth s gravity field hydrological and oceanic effects and their possible detection using grace the grace satellite mission scheduled for launch in 2001 is designed to map out the earth s gravity field to high accuracy every 2 4 weeks over a nominal lifetime of 5 years changes in the gravity field are caused by the redistribution of mass within the earth and on or above its surface grace will thus be able to constrain processes that involve mass redistribution in this paper we use output from hydrological oceanographic and atmospheric models to estimate the variability in the gravity field i e in the geoid due to those sources we develop a method for constructing surface mass estimates from the grace gravity coefficients we show the results of simulations where we use synthetic grace gravity data constructed by combining estimated geophysical signals and simulated grace measurement errors to attempt to recover hydrological and oceanographic signals we show that grace may be able to recover changes in continental water storage and in seafloor pressure at scales of a few hundred kilometers and larger and at timescales of a few weeks and longer with accuracies approaching 2 mm in water thickness over land and 0 1 mbar or better in seafloor pressure

possible tsunami inundation identified amongst 4 5th century bce archaeological deposits at tel ashkelon israel abstract the eroding coastal sections of ashkelon israel contain exposed sequences of natural and anthropogenic sedimentological deposits some of unknown origin ashkelon an important and long occupied ancient coastal city is directly referred to within written records of past tsunami events yet field studies and archaeological descriptions have not yet corroborated these claims this is not unusual nor unexpected given the amount of anthropogenic and natural disturbance that can erase the sedimentary remains as well as the relatively recent advancements in identifying such deposits a sequence of sediments at the base of an eroding coastal archaeological section shows clear waterborne transport characteristics and was previously interpreted as alluvial however no alluvial sources could be associated to the deposit in this study the sedimentological characteristics of this section were described and analyzed in greater detail to determine their nearest similarity to possible transport mechanism such as storms rivers and tsunamis the deposits contain fining upward sequences rip up clasts imbricated inclusions fine mud layers microfauna foraminifera and broken diagnostic pottery from the 4 5th c bc reconstructions of the coastline at the time of the event place the sampled profile at least 100 m inland from the shoreline at an elevation 2 0 to 2 4 m above sea level river channel features were not identified in the section for this area modern observations of major storms show inundations of

cementing halite in triassic bunter sandstone tonder southwest denmark as a result of hyperfiltration of brines abstract samples of cores from the bunter sandstone formation of the tonder structure have been carefully prepared without access of fresh water the presence of cementing halite has been proven by chemical analysis and microscopic studies of these samples computer log analysis combined with core analysis show the cementing halite to exist mainly in the sandstone layers of the upper bunter sand unit the depositional environments of the bunter sandstone formation of the tonder structure are outlined it is argued that the cementing halite formed as a result of hyperfiltration of the saturated formation brines through low permeable layers of shale this process took place during the emplacement of nitrogen gas in the upper bunter sand unit late in the diagenetic history of the sandstone

ocean bottom pressure variability can it be reliably modeled ocean bottom pressure obp variability serves as a proxy of ocean mass variability the knowledge of which is needed in geophysical applications the question of how well it can be modeled by the present general ocean circulation models on time scales in excess of one day is addressed here by comparing the simulated obp variability with the observed one to this end a new multi year data set is used obtained with an array of bottom pressure gauges deployed deeply along a transect across the southern ocean we present a brief description of obp data and show large scale correlations over several thousand kilometres at all time scales red using daily and monthly averaged data annual and semi annual cycles are weak close to the agulhas retroflection signals of up to 30 cm equivalent water height ewh are detected further south signals are mostly intermittent and noisy it is shown that the models simulate consistent patterns of bottom pressure variability on monthly and longer scales except for areas with high mesoscale eddy activity where high resolution is needed to capture the variability due to eddies furthermore despite good agreement in the amplitude of variability the in situ and simulated obp show almost no correlation

source parameter inversion for recent great earthquakes from a decade long observation of global gravity fields we quantify gravity changes after great earthquakes present within the 10 year long time series of monthly gravity recovery and climate experiment grace gravity fields using spherical harmonic normal mode formulation the respective source parameters of moment tensor and double couple were estimated for the 2004 sumatra andaman earthquake the gravity data indicate a composite moment of 1 2 1023 n m with a dip of 10 in agreement with the estimate obtained at ultralong seismic periods for the 2010 maule earthquake the grace solutions range from 2 0 to 2 7 1022 n m for dips of 12 24 and centroid depths within the lower crust for the 2011 tohoku oki earthquake the estimated scalar moments range from 4 1 to 6 1 1022 n m with dips of 9 19 and centroid depths within the lower crust for the 2012 indian ocean strike slip earthquakes the gravity data delineate a composite moment of 1 9 1022 n m regardless of the centroid depth comparing favorably with the total moment of the main ruptures and aftershocks the smallest event we successfully analyzed with grace was the 2007 bengkulu earthquake with m0 5 0 1021 n m we found that the gravity data constrain the focal mechanism with the centroid only within the upper and lower crustal layers for thrust events deeper sources i e in the upper mantle could not reproduce the gravity observation as the larger rigidity and bulk modulus at mantle depths inhibit the interior from changing its volume thus reducing the negative gravity component focal mechanisms and seismic moments obtained in this study represent the behavior of the sources on temporal and spatial scales exceeding the seismic and geodetic spectrum

computations of the viscoelastic response of a 3 d compressible earth to surface loading an application to glacial isostatic adjustment in antarctica and canada s u m m a r y we develop a 3 d finite element model to study the viscoelastic response of a compressible earth to surface loads the effects of centre of mass motion polar wander feedback and selfconsistent ocean loading are implemented to assess the model s accuracy we benchmark the numerical results against a semi analytic solution for spherically symmetric structure we force our model with the ice 5g global ice loading history to study the effects of laterally varying viscosity structure on several glacial isostatic adjustment gia observables including relative sea level rsl measurements incanada and present day time variable gravity and uplift rates in antarctica canadian rsl observations have been used to determine the earth s globally averaged viscosity profile antarcticgps uplift rates have been used to constrainantarcticgia models and gia time variable gravity and uplift signals are error sources for grace and altimeter estimates of present day antarctic ice mass loss and must be modelled and removed from those estimates computinggia results for a 3 d viscosity profile derived from a realistic seismic tomography model and comparing with results computed for 1 d averages of that 3 d profile we conclude that 1 a gia viscosity model based on canadian relative sea level data is more likely to represent a canadian average than a true global average 2 the effects of 3 d viscosity structure on grace estimates of present day antarctic mass loss are probably smaller than the difference between gia models based on different antarctic deglaciation histories and 3 the effects of 3 d viscosity structure on antarctic gps observations of present day uplift rate can be significant and can complicate efforts to use gps observations to constrain 1 d gia models

precise comparisons of bottom pressure and altimetric ocean tides 1 a new set of pelagic tide determinations is constructed from seafloor pressure measurements obtained at 151 sites in the deep ocean to maximize precision of estimated tides only stations with long time series are used median time series length is 567 days geographical coverage is considerably improved by use of the international tsunami network but coverage in the indian ocean and south pacific is still weak as a tool for assessing global ocean tide models the data set is considerably more reliable than older data sets the root mean square difference with a recent altimetric tide model is approximately 5 mm for the m2 constituent precision is sufficiently high to allow secondary effects in altimetric and bottom pressure tide differences to be studied the atmospheric tide in bottom pressure is clearly detected at the s1 s2 and t2 frequencies the altimetric tide model is improved if satellite altimetry is corrected for crustal loading by the atmospheric tide models of the solid body tide can also be constrained the free core nutation effect in the k1 love number is easily detected but the overall estimates are not as accurate as a recent determination with very long baseline interferometry

the relationship between sea level and bottom pressure variability in an eddy permitting ocean model we investigate the relationship between sea level after application of an inverse barometer correction and ocean bottom pressure in an eddy permitting ocean model we find the presence of eddies can disrupt this relationship even on timescales as short as 10 20 days but only in the regions of most energetic eddy variability away from eddies the relationship is similar to that seen in a coarserresolution model with a tight relationship between sea level and bottom pressure at high frequencies but with significant correlations between sea level and bottom pressure at interannual timescales seen only in shelf sea regions in the deep ocean regions where sea level and bottom pressure remain related out to the longest timescales are in the arctic ocean and regions of the southern ocean where particularly large amplitude barotropic fluctuations are found but where the mesoscale signal is weak

long period tidal variations in the length of day a new model of long period tidal variations in length of day is developed the model comprises 80 spectral lines with periods between 18 6 years and 4 7 days and it consistently includes effects of mantle anelasticity and dynamic ocean tides for all lines the anelastic properties follow wahr and bergen experimental confirmation for their results now exists at the fortnightly period but there remains uncertainty when extrapolating to the longest periods the ocean modeling builds on recent work with the fortnightly constituent which suggests that oceanic tidal angular momentum can be reliably predicted at these periods without data assimilation this is a critical property when modeling most long period tides for which little observational data exist dynamic ocean effects are quite pronounced at shortest periods as out of phase rotation components become nearly as large as in phase components the model is tested against a 20 year time series of space geodetic measurements of length of day the current international standard model is shown to leave significant residual tidal energy and the new model is found to mostly eliminate that energy with especially large variance reduction for constituents sa ssa mf and mt

rapid eddy induced modification of subtropical mode water during the kuroshio extension system study abstractfrom 2004 to 2006 an observational array of current and pressure recording inverted echo sounders cpies were deployed as part of the kuroshio extension kex system study kess kess observed a transition from a weakly meandering stable to strongly meandering unstable state qiu and chen as the kex made this transition potential vorticity pv observed within the southern recirculation gyre srg rapidly increased from january to july 2005 in this study the authors diagnose eddy pv fluxes epvfs in isentropic coordinates within the subtropical mode water stmw layer from the cpies data to determine the role of mesoscale eddies in this rapid increase of pv the rapid increase in pv within the srg coincided with enhanced cross front epvfs and eddy pv flux convergence upstream of a mean trough in the kex path and adjacent to the srg the enhanced cross front epvfs were the result of the formation of a cold core ring ccr and the interaction of the jet with a preexisting ccr eddy d

the gravity recovery and climate experiment mission overview and early results 1 the grace mission is designed to track changes in the earth s gravity field for a period of five years launched in march 2002 the two grace satellites have collected nearly two years of data a span of data available during the commissioning phase was used to obtain initial gravity models the gravity models developed with this data are more than an order of magnitude better at the long and mid wavelengths than previous models the error estimates indicate a 2 cm accuracy uniformly over the land and ocean regions a consequence of the highly accurate global and homogenous nature of the grace data these early results are a strong affirmation of the grace mission concept

luminescence chronology of aeolianites from the section at givat olga coastal plain of israel abstract the eastern mediterranean coastal plain of israel is composed mainly of loam sand and gravel of pleistocene to holocene age indicating an alternation of marine coastal and continental environments owing to the complexity of the numerous exposures of aeolianites kurkar and soils hamra in the elongated ridges along the coastal plain it is difficult to set up a reliable stratigraphy a systematic luminescence dating study was carried out on loose sand kurkar and hamra deposits in the coastal plain between netanya and haifa sixteen samples were taken and investigated from the section at givat olga the chronological results show excellent agreement between the infrared optically stimulated luminescence irsl and thermoluminescence tl techniques indicating that the former sand dunes were well bleached prior to deposition the irsl and tl age estimates range from about 75 3 ka for the aeolianites indicating that this kurkar ridge formed during an older period of the last glaciation likely before 50 ka

an isochemical model for formation of authigenic kaolinite k feldspar and illite in sediments abstract although thermodynamic calculations indicate a narrow range of conditions for coprecipitation of kaolinite and k feldspar coexistence of authigenic kaolinite and k feldspar is common in jurassic sandstones of the north sea this paper shows that the coexistence of authigenic k feldspar and kaolinite may indicate that this narrow range of conditions did prevail and that the system behaved as a closed system these conditions are presence of muscovite in the sediment pore waters supersaturated with respect to quartz and temperatures lower than 50 c at higher temperatures the authigenic kaolinite and authigenic k feldspar may react and form authigenic illite muscovite and quartz cement the direction of the isochemical reaction is thermodynamically determined by the degree of supersaturation with respect to quartz in the formation water published data on the degree of supersaturation with respect to quartz in formation waters suggest that the illitization of kaolinite may take place at temperatures as low as 50 c much lower than previously believed

authigenic k feldspar in the bromsgrove sandstone formation triassic of ccntral england abstract authigenic k feldspar is a ubiquitous feature of the bromsgrove sandstone formation triassic in central england it occurs mainly as partially to completely developed euhedral overgrowths on detrital k feldspar cores the authigenic k feldspar is virtually pure kalsi3o8 potassian low sanidine and occurs as optically continuous overgrowths on detrital sanidine and optically discontinuous overgrowths on detrital orthoclase differences in structure and al si disorder thus control the degree of optical continuity of the overgrowths an important feature is the presence of optically and compositionally zoned overgrowths due to minor fluctuations in the bao and na2o content the formation of the overgrowths was dependent upon intrastratal dissolution of detrital grains for a supply of potassium aluminum and silicon precipitation took place within the k2o na2o al2o3 sio2 h2o system and in association with other phases in this system the diagenetic sequence 1 illite 2 quartz 3 k feldspar 4 illite 5 kaolinite is consistent with a progressive increase in k h ratio or h4sio4 activity followed by a general decrease so that the later interstitial fluids were much depleted in k ions and kaolinite was the final phase to precipitate

time variations in ocean bottom pressure from a few hours to many years in situ data numerical models and grace satellite gravimetry in situ ocean bottom pressure obp obtained from 154 different locations irregularly scattered over the globe is carefully processed to isolate signals related to the ocean general circulation and large scale sea level changes comparison against a global numerical ocean model experiment indicates poor correspondence for periods below 24 hr possibly related to residual tidal signals and small timing errors in the atmospheric forcing applied to the ocean model correspondence increases rapidly for periods between 3 and 10 days where wind driven dynamics are already well understood and consequently well implemented into numerical models coherence decreases again for periods around 30 days and longer where processes not implemented into ocean general circulation models as barystatic sea level changes become more important correspondence between in situ data and satellite based obp as obtained from the gravity recovery and climate experiment grace german research centre for geosciences rl05a gravity fields critically depends on the postprocessing of level 2 stokes coefficients that also includes the selection of appropriate averaging regions for the grace based mass anomalies the assessment of other available grace level 2 products indicates even better fit of more recent solutions as itsg grace2016 and the center for space research and jet propulsion laboratory rl05 mascons in view of the strong high frequency component of obp however a higher temporal resolution of the oceanic grace products would be rather advantageous

estimating geocenter variations from a combination of grace and ocean model output 1 in this study we estimate a time series of geocenter anomalies from a combination of data from the gravityrecoveryandclimateexperiment grace satellitemissionandthe outputfromoceanmodels amatrixequationisderivedrelating totalgeocentervariations to the grace coefficients of degrees two and higher and to the oceanic component of the degree one coefficients we estimate the oceanic component from two state of the art ocean models results are compared to independent estimates of geocenter derived from other satellite data such as satellite laser ranging and gps finally we compute degree one coefficients that are consistent with the processing applied to the grace level 2 gravity field coefficients the estimated degree one coefficients can be used to improve estimates of mass variability from grace which alone cannot provide them directly

holocene evolution of the haifa bay area israel and its influence on ancient tell settlements the geographical evolution of haifa bay and zevulun plain israel from the late pleistocene to the holocene is based on detailed analysis of drilled cores at the beginning of the holocene the bay area was still under terrestrial conditions only about 9500 to 9000 cal yr bp when sea level rose to about 35 30 m below present sea level b s l did nile derived sand start to bypass the carmel headland and haifa bay come into existence as a morphological feature between 8000 and 7150 cal yr bp when sea level was 14 10 m b s l the invading sea crossed the present day coastline at about 6800 to 6600 cal yr bp sea level rose to about 5 m b s l and flooded the zevulun plain up to 2 km inland and the river qishon estuary up to 4 km inland it is still unknown exactly when the sea reached its maximum penetration inland but later about 4000 years ago the coastline in the research area was still east of the present day coast up to 3 km in the zevulun plain and 4 8 km in the river qishon estuary when the coastline started to retreat westward the reclamation was followed by intensive deposition of shallow marine sand and aeolian dunes while to the east different wetland conditions developed the archaeological data indicate that during the early bronze age i and early bronze age ii dated to between 5600 and 4700 cal yr bp and even later during the middle bronze age ii period about 4600 to 3500 cal yr bp the coastline was still east of the present day coast but it never actually reached the bases of most of the tells as has been suggested except for tel akko and tel abu hawam

aeolian stratification and facies association in desert sediments arran basin permian scotland abstract permian aeolian sediments on the island of arran are divisible into dune including draa and interdune deposits both types display a distinctive and unusually wide variation in grain size the dominant features of the dune deposits are grainfall lamination sandflow lamination and inverse graded lamination associated with ripple form lamination and normal graded lamination the flat lying aeolian interdune deposits are characterised by granule and sand ripples horizontal lamination in coarse sand and granules plane bed lamination and inverse graded lamination associated structures include ripple form lamination and deflation lags three types of trace fossil associated with completely bioturbated horizons occur in some low angle dune and interdune deposits the aeolian facies interfinger with alluvial fan deposits giving rise to three recognizable facies belts marginal aeolian deposits are associated with fluvial conglomerates and are dominated by interdune deposits and occasionally very thin barchan deposits set height 3 37 cm intermediate aeolian deposits are characterized by interbedded crescentic dune small draa dune set height 5 cm 4 5 m and interdune deposits and rare fluvial and lake sediments basinal aeolian deposits are dominated by draa deposits dune set height 0 2 28 m associated with rare interdune sediments transverse dunes and draas were moved by north eastern palaeowinds towards the foot of the alluvial fans the aeolian sediments were deposited in a fault bounded desert basin

recent contributions of glaciers and ice caps to sea level rise satellite measurements of earth s gravity field show that the mass loss of glaciers and ice caps contributed to sea level rise by approximately 0 4 millimetres per year between 2003 and 2010 the extent to which mass loss from ice covered land areas contributes to sea level rise is not known accurately in part because previous global estimates use different techniques for glaciers ice caps and ice sheets the gravity recovery and climate experiment grace satellite has provided monthly measurements of the global gravity field since 2002 using grace data jacob et al assess regional mass loss between 2003 and 2010 and conclude that mass loss from ice covered land areas contributed almost 1 5 mm per year to the sea level rise estimated mass loss from the high mountains of asia was negligible in contrast to some other reports glaciers and ice caps gics are important contributors to present day global mean sea level rise1 2 3 4 most previous global mass balance estimates for gics rely on extrapolation of sparse mass balance measurements1 2 4 representing only a small fraction of the gic area leaving their overall contribution to sea level rise unclear here we show that gics excluding the greenland and antarctic peripheral gics lost mass at a rate of 148 30 gt yr 1 from january 2003 to december 2010 contributing 0 41 0 08 mm yr 1 to sea level rise our results are based on a global simultaneous inversion of monthly grace derived satellite gravity fields from which we calculate the mass change over all ice covered regions greater in area than 100 km2 the gic rate for 2003 2010 is about 30 per cent smaller than the previous mass balance estimate that most closely matches our study period2 the high mountains of asia in particular show a mass loss of only 4 20 gt yr 1 for 2003 2010 compared with 47 55 gt yr 1 in previously published estimates2 5 for completeness we also estimate that the greenland and antarctic ice sheets including their peripheral gics contributed 1 06 0 19 mm yr 1 to sea level rise over the same time period the total contribution to sea level rise from all ice covered regions is thus 1 48 0 26 mm 1 which agrees well with independent estimates of sea level rise originating from land ice loss and other terrestrial sources6

sediment contribution from israel s coastal cliffs into the nile s littoral cell and its significance to cliff retreat mitigation efforts abstract we quantify the volumetric erosion of israel s actively retreating mediterranean coastal cliffs between 2006 and 2015 with airborne lidar our results reveal annual sand contribution of 45 000 m3 from the coastal cliffs into the nile s littoral cell nlc which amounts to 50 of the annual long shore sand transport previously measured at the northern termination of the nlc accordingly we find that implementation of cliff retreat mitigation engineering efforts planned for israel s coastline can lead to a sand deficit in the nlc that may result in increased beach erosion