provenancing and archaeology of roman millstones from the mediterranean area abstract roman rotary grain mills in the mediterranean area are mainly of two styles hourglass shaped pompeian style mills and flatter cylindrical millstones many of these millstones are made of igneous rocks imported to the sites where the mills are found and they may therefore be important indicators of resource procurement and trade if the source of the rock of manufacture can be traced three types of igneous rock were used to make millstones 1 reddish rhyolitic ignimbrite 2 leucite phyric lavas and 3 generally fresh grey vesicular lavas of basic intermediate composition potential source rocks and millstones of all three types of rock were characterized using petrographic examination in thin section and chemical analysis for major and 15 trace elements determined by low dilution fusion wavelength dispersive x ray fluorescence analysis one hundred and forty six millstones and lavas from archaeological contexts were studied and 113 of these were successfully assigned to geological sources sixteen areas of igneous rocks were used by the romans for millstone production these include the basic and intermediate composition grey vesicular lavas of olot northeast spain agde southern france volvic and possibly the le puy area central and southeast france respectively vulture italy etna and monti iblei in sicily pantelleria sardinia ustica the aeolian islands nisyros aegean libya and the middle atlas and rif areas of morocco the red rhyolite was quarried at the village of mulargia in sardinia and the leucite phyric rocks originated on the italian mainland including the quarry of orvieto in umbria there is a wide variation in size and style of millstones from individual production centres and some were exported in unfinished form grey vesicular millstones were traded up to at least 820 km from their sources and fall into four mainly separate distributions in the mediterranean the mulargia rhyolite and the leucitites were moved mainly from north to south were traded further than the grey vesicular rocks and were probably the most desirable types they are found 1350 and 1500 km distant from their sources respectively the millstones were moved mainly by sea perhaps on grain collecting ships on outward voyages from italy to the south and west of the mediterranean

comments on on the focusing issue of synthetic aperture radar imaging of ocean waves by c bruning et al in the above named work see ibid vol 29 p 120 8 1991 c bruning et al present results that show the application of the velocity bunching model to synthetic aperture radar sar images obtained during the tower ocean wave and radar dependence toward experiment the commenters argue that some of the observations presented require classification and discussion an attempt is made in this comment to clarify the issues and to present some new relevant results obtained from the sar x band and ocean nonlinearities chesapeake light tower saxon clt experiment

post collisional tertiary quaternary mafic alkalic magmatism in the carpathian pannonian region a review mafic alkalic volcanism was widespread in the carpathian pannonian region cpr between 11 and 0 2 ma it followed the miocene continental collision of the alcapa and tisia blocks with the european plate as subduction related calc alkaline magmatism was waning several groups of mafic alkalic rocks from different regions within the cpr have been distinguished on the basis of ages and or trace element compositions their trace element and sr nd pb isotope systematics are consistent with derivation from complex mantle source regions which included both depleted asthenosphere and metasomatized lithosphere the mixing of dmm himu emii mantle components within asthenosphere derived magmas indicates variable contamination of the shallow asthenosphere and or thermal boundary layer of the lithosphere by a himu like component prior to and following the introduction of subduction components various mantle sources have been identified lower lithospheric mantle modified by several ancient asthenospheric enrichments source a young asthenospheric plumes with oib like trace element signatures that are either isotopically enriched source b or variably depleted source c old upper asthenosphere heterogeneously contaminated by dm himuemii emi components and slightly influenced by miocene subduction related enrichment source d old upper asthenosphere heterogeneously contaminated by dm himu emii components and significantly influenced by miocene subduction related enrichment source e melt generation was initiated either by i finger like young asthenospheric plumes rising to and heating up the base of the lithosphere below the alcapa block or ii decompressional melting of old asthenosphere upwelling to replace any lower lithosphere or heating and melting former subducted slabs the tisia block d 2004 published by elsevier b v

differential behaviour of the rb sr and k ar systems of spilitic flows and interbedded metasediments the spilite group of erquy brittany france paleomagnetic implications the erquy series cotes du nord france consists in its upper part of spilitic pillow lavas with some interbedded volcano sedimentary horizons

nonlocality of atlantic tropical cyclone intensities 1 the assumption that tropical cyclones respond primarily to sea surface temperatures ssts local to their main development regions underlies much of the concern regarding the possible impacts of anthropogenic greenhouse warming on tropical cyclone statistics here the observed relationship between changes in sea surface temperature and tropical cyclone intensities in the atlantic basin is explored atlantic tropical cyclone intensity fluctuations and storm numbers are shown to depend not only upon sst anomalies local to the atlantic main development region but also in a negative sense upon the tropical mean sst this behavior is shown in part to be consistent with changes in the tropical cyclone potential intensity that provides an upper bound on storm intensity however atlantic tropical cyclone intensity fluctuations are more nonlocal than the potential intensity itself and specifically vary along with atlantic main development region sst anomalies relative to the tropical mean sst this suggests that there is no straightforward link between warmer ssts in the main development region and more intense tropical cyclones

from alkali basalt to phonolite in hand size samples vapor differentiation effects in the bouzentes lava flow cantal france abstract the bouzentes lava flow is a 20 m thick alkali basalt flow emplaced during the last stage of formation of the cantal stratovolcano at 4 2 ma its upper part has 1 to 20 cm thick vesicle rich segregation sheets which recur every 0 1 2 m these horizontal veins are hawaiitic in composition they are characterized by hypertrophic development of their minerals pegmatoids and by glassy phonolitic segregation vesicles internal differentiation within the bouzentes lava flow was triggered by an unusually high water content as suggested by pre emptive iddingsite alteration of olivine phenocrysts the proposed model of formation of the segregation sheets includes the upward motion of diapirs of residual melt plus addition of vapor from the bottom of the central liquid lens to the base of the upper solidified crust of the cooling lava flow olivine settling appears to have been inhibited or at least retarded by upward migration of melt plus vesicles most of the features observed in bouzentes recall the internal differentiation processes usually described within thick hawaiian lava lakes the segregation vesicles are believed to result from an increase of gas solubility in residual melt during the crystallization process

models for synthetic aperture radar imaging of the ocean a comparison theoretical comparisons are made of different models for synthetic aperture radar sar imaging of ocean waves the velocity bunching model distributed surface model lyzenga model canadian center for remote sensing radarsat ccrs radarsat model and the ocean research and engineering ore model are compared analytically with respect to their description of the sar imaging process and the radar backscatter process the study concentrates on the temporal description of the backscatter process and its impact on sar imaging of the ocean sample simulations are conducted so as to quantify some of the similarities and differences of the aforementioned models other sar imaging models are discussed as they pertain to the comparisons noted above the analytical and numerical simulations show that the lyzenga model the ccrs radarsat model and the ore model are similar for most commonly occurring sea states the velocity bunching model is similar to these models when the sar integration time is small but it tends to deviate for long integration times the distributed surface model is shown to describe the imaging process adequately when the radar backscatter is highly correlated in space and time

atlantic seasonal hurricane frequency part i el nino and 30 mb quasi biennial oscillation influences abstract this is the first of two papers on atlantic seasonal hurricane frequency in this paper seasonal hurricane frequency as related to e1 nino events during 1900 82 and to the equatorial quasi biennial oscillation qbo of stratospheric zonal wind from 1950 to 1982 is discussed it is shown that a substantial negative correlation is typically present between the seasonal number of hurricanes hurricane days and tropical storms and moderate or strong 15 cases el nin off the south american west coast a similar negative anomaly in hurricane activity occurs when equatorial winds at 30 mb are from an easterly direction and or are becoming more easterly with time during the hurricane season this association of atlantic hurricane activity with el nino can also be made with the southern oscillation index by contrast seasonal hurricane frequency is slightly above normal in non el nino years and substantially above normal when equatorial stratospheric winds blow from a westerly direction and or are bec

petrological and geochemical relationships between pyroxene megacrysts and associated alkali basalts from massif central france major trace element and ree analyses as well as sr isotopic ratios have been obtained on twelve clinopyene megacrysts and phenocrysts and their alkali basalt hosts from the french massif central equilibrium between crystals and host was examined based on petrographic and geochemical data two types of pyroxenes are recognized the acmite bearing clinopyroxenes rich in incompatible elements and the salitic clinopyroxenes poor in incompatible elements 87sr 86sr isotopic data reveal no significant difference between clinopyroxenes and host lavas they are in apparent isotopic equilibrium the sr isotopic ratios of the two types of pyroxenes are also quite similar however pyroxene crystals from the first group are not in equilibrium with their host they have crystallized at high pressure from differentiated alkali lavas and have been incorporated in a more primitive magma pyroxene crystals from the second group are in apparent equilibrium with their host lava they have crystallized at various pressures for the latter distribution coefficients are proposed for compatible elements trace elements and ree

focusing simulations of synthetic aperture radar ocean images the sar ocean images obtained in the tower ocean wave and radar dependence experiment toward are carefully analyzed at different focus settings and compared with simulated results based on various theories for imaging surface waves the agreement between the experimental data and all of the sar simulations except one is found to be favorable there is also surprisingly close agreement among the different theoretical models themselves suggesting a closer fundamental similarity among the contending theories than was previously thought it is shown that the width of the focusing curve has an inverse dependence on the sar integration time for the toward conditions it is found that the image modulation due to azimuth traveling surface waves is greater than that due to range traveling waves

tropical sea surface temperature vertical wind shear and hurricane development 1 the anomalously strong hurricane activity in the atlantic sector during the recent years led to a controversy about the impact of global warming on hurricane activity in the atlantic sector here we show that the temperature difference between the tropical north atlantic and the tropical indian and pacific oceans indo pacific is a key parameter in controlling the vertical wind shear over the atlantic an important quantity for hurricane activity the stronger warming of the tropical north atlantic relative to that of the indo pacific during the most recent years drove reduced vertical wind shear over the atlantic and is thus responsible for the strong hurricane activity observed in 2006 however the temperature difference between the tropical north atlantic and the tropical indian and pacific oceans is much reduced which explains the relatively weak hurricane season

the two scale radar wave probe and sar imagery of the ocean a two scale formulation of oceanic backscatter of microwave radiation which has previously been applied to the dual frequency scatterometer is applied here to the two scale radar wave probe and sar imagery of the ocean a two scale radar wave probe is a microwave system which coherently detects signals scattered from a very small patch of the ocean surface it is shown that a sar image may be described as a convolution of the am part of the output of a two scale wave probe with the power spectrum of the fm part of the output thus sar images are not faithful reproductions of cross section variations over the surface distortions occur as a result of variable surface velocities examples of this distortion are derived from two scale wave probe data taken in the gulf of mexico application of a focusing correction does not remove the distortion from the simulated image of a nearly sinusoidal azimuth traveling wave large v r0 ratios minimize the distortion however

focusing of synthetic aperture radar ocean images with long integration times synthetic aperture radar sar images obtained in the sar and x band ocean nonlinearities chesapeake light tower saxon clt experiment are processed with long integration times 6 s and analyzed to study the effects of focusing two images with near azimuth traveling waves were chosen for the study the first image consists of relatively short wavelength wind waves traveling in the same general direction as the aircraft the second image consists of a long atlantic swell traveling in the opposite direction to the aircraft at these long integration times the image spectral intensities are found to be sensitive to the focus setting the spectral intensity at the optimum focus is 400 of that at zero focus for the first image and 167 for the second image the focusing curves for both images agree well with those predicted by a model developed by several groups and referred to here as the consensus model this model predicts an optimum focus setting that is equal to one half of the effective phase speed of the dominant wave in the azimuth direction the velocity bunching model underpredicts the optimum focus setting significantly the study concludes that in long integration time sar processing of surface waves such as the spotlight mode the image contrast is sensitively dependent on the focus setting and that the optimum focus setting is given by one half of the effective phase speed of the dominant surface wave

diagnosis of the mjo modulation of tropical cyclogenesis using an empirical index the modulation of tropical cyclone activity by the madden julian oscillation mjo is explored using an empirical genesis potential gp index composite anomalies of the genesis index associated with the different mjo phases are consistent with the composite anomalies in tc genesis frequency that occur in the same phases indicating that the index captures the changes in the environment that are at least in part responsible for the genesis frequency changes of the four environmental variables that enter the genesis potential index the midlevel relative humidity makes the largest contribution to the mjo composite gp anomalies the second largest contribution comes from the low level absolute vorticity and only very minor contributions come from the vertical wind shear and potential intensity when basin integrated mjo composite anomalies of the gp index are regressed against basin integrated composite anomalies of tc genesis frequency the results differ quantitatively from those obtained from the analogous calculation performed on the annual climatologies in the two quantities the gp index captures the mjo modulation of tc genesis to a lesser degree than the climatological annual cycle of genesis to which it was originally tuned this may be due to weaknesses of the reanalysis or indicative of the importance of precursor disturbances not well captured in the gp index computed from weekly data to the intraseasonal tc genesis frequency fluctuations

theory for synthetic aperture radar imaging of the ocean surface with application to the tower ocean wave and radar dependence experiment on focus resolution and wave height spectra a one dimensional model is developed to simulate azimuthal synthetic aperture radar sar imaging of the ocean surface the model developed here is general and can admit both the distributed surface and the velocity bunching approaches computer simulations are performed to test the validity of this model the simulations show that the time dependent modulation patterns due to the radar cross section variation and the velocity bunching effects give optimum focusing around half the phase velocity of the long wave it is shown that the focus dependence is due to an incoherent integration process and not due to motion induced phase errors it is argued that the radar reflectivity is correlated over distances small in comparison with the sar resolution in the simulations the radar reflectivity is assumed to be spatially decorrelated also given are the relative importance of the various effects that degrade the azimuthal resolution it is shown that the limited radar temporal coherence due to the velocity spread of short waves degrades the azimuthal resolution of the sar this coherence time depends on sea state and radar wavelength it is shown that the orbital acceleration effects are small in comparison with the smearing due to the velocity spread it is found that the degraded azimuthal resolution of the radar minimizes the nonlinear effects of velocity bunching the simulations show that in the tower ocean wave and radar dependence experiment toward sar imaging at l band is reasonably linear

multifocus processing of l band synthetic aperture radar images of ocean waves obtained during the tower ocean wave and radar dependence experiment as part of the tower ocean wave and radar dependence experiment toward objectives the mechanisms of sar imaging of ocean waves are investigated using l band sar data over the naval ocean systems center tower this paper provides experimental evidence needed to validate the differing hypotheses various processing methods are investigated to generate spectra with large degrees of freedom the results show that waves traveling in the aircraft direction are most detectable at focus settings in the range 10 0 15 0 m s which is consistent with the marine remote sensing experiment marsen observations reported by jain and shemdin 1983 waves traveling in the direction opposite to the aircraft are most detectable at settings equal to 5 0 to 15 0 m s the sar imaging system acts as a low pass filter with the peak of the ocean wave height spectrum occurring at higher wave numbers compared with the peak in the sar image spectrum

systematic variation of summertime tropical cyclone activity in the western north pacific in relation to the madden julian oscillation abstract the variability of observed tropical cyclone tc activity i e genesis track and landfall in the western north pacific wnp is examined in relation to the various categories of the madden julian oscillation mjo during summer june september for the period 1979 2004 the mjo categories are defined based on the empirical orthogonal function analysis of outgoing longwave radiation data the number of tcs increases when the mjo related convection center is located in the wnp the axis of a preferable genesis region systematically shifts like a seesaw in response to changes in the large scale environments associated with both the eastward and northward propagation of the mjo and the intraseasonal variability of the wnp subtropical high furthermore the authors show that the density of tc tracks in each mjo category depends on the systematic shift in the main genesis regions at first order also the shift is affected by the prevailing large scale steering flows in each mjo category when th

mjo and tropical cyclogenesis in the gulf of mexico and eastern pacific case study and idealized numerical modeling the role of the madden julian oscillation mjo in modulating the frequency and location of tropical cyclogenesis over the eastern pacific and the gulf of mexico during august september 1998 is examined during the nonconvective phase of the mjo convection and low level cyclonic vorticity occurred primarily in conjunction with the intertropical convergence zone itcz during the convective phase convection low level cyclonic vorticity and convergence expanded into the northeastern pacific and the gulf of mexico this was accompanied by enhanced eddy kinetic energy and barotropic energy conversions as compared to the nonconvective phase consistent with previous research during the nonconvective phase of the mjo vertical shear was relatively weaker but tropical cyclones tended to form mainly within the itcz on the contrary during the convective phase vertical wind shear exceeded 10 m s 1 over much of this region and tropical cyclone development occurred north of the itcz near the mexican pacific coast and the gulf of mexico idealized numerical experiments are conducted using a barotropic model with time invariant basic states representative of the nonconvective and convective phases of the mjo the simulations indicate that the propagation paths as well as the amplification of the eddies differ substantially between the two phases during the nonconvective phase the waves tend to propagate westward into the eastern pacific during the convective phase stronger southerlies steer the waves into the gulf of mexico the mjo related modulation of tropical cyclogenesis in the eastern pacific and gulf of mexico thus appears to involve anomalous convergence cyclonic vorticity vertical wind shear and differing tracks of easterly waves

low frequency equatorial waves in vertically sheared zonal flow part i stable waves abstract the mechanism by which a vertically sheared zonal flow affects large scale low frequency equatorial waves is investigated with two level equatorial plane and spherical coordinates models vertical shears couple barolinic and barotropic components of equatorial wave motion affecting significantly the rossby wave and westward propagating yanai wave but not the kelvin wave this difference results from the fact that the barotropic component is a modified rossby mode and can be resonantly excited only by westward propagating internal waves the barotropic components emanate poleward into the extratropics with a pronounced amplitude while the baroclinic components remain equatorially trapped a westerly vertical shear favors the trapping of rossby and yanai waves in the upper troposphere whereas an easterly shear tends to confine them in the lower troposphere as such their westward propagation is slowed down by both westerly and easterly shears when the strength of the vertical shear varies w

reconciliation of theories of synthetic aperture radar imagery of ocean waves several theories of synthetic aperture radar sar imagery of ocean waves especially those dealing with the focusing issue are examined we show that the time dependent theories of lyzenga 1988 and of kasilingam and shemdin 1988 and the velocity bunching theory of bruning alpers and shroter 1991 are identical for short integration times but diverge on the focusing issue for long integration times the reason for the divergence is simply that velocity bunching theory assumes that integration times are short compared with ocean wave periods the inference is that the phase speed of the ocean wave plays a secondary nearly negligible role to that of orbital velocity and acceleration in determining the optimum focus setting for short integration times but becomes dominant as integration times are increased for the case of zero focus adjustment these focus dependent theories are shown to reduce to those of plant and keller 1983 and of hasselmann et al 1985 thus several of the apparently differing theories of sar imagery of the ocean are reconciled and shown to be a single consistent theory

modulation of eastern north pacific hurricanes by the madden julian oscillation abstract hurricane and tropical storm statistics verify the modulation of eastern pacific tropical systems by the madden julian oscillation mjo as hypothesized by maloney and hartmann over twice as many named tropical systems hurricanes and tropical storms accompany equatorial 850 mb westerly anomalies than accompany equatorial easterly anomalies and the systems that do exist are stronger hurricanes are over four times more numerous during westerly phases of the mjo than during easterly phases the current study constructs a composite life cycle of the mjo during may november 1979 95 using an index based on the 850 mb equatorial zonal wind equatorial kelvin waves propagating eastward from convective regions of the western pacific ocean alter dynamical conditions over the eastern pacific ocean westerly easterly equatorial 850 mb wind anomalies are accompanied by enhanced suppressed convection over the eastern pacific hurricane region convection locally amplifies the wind anomalies over the ea

evolution of magma mixing in an alkaline suite the grande cascade sequence monts dore french massif central geochemical modelling abstract trachyandesitic lavas from an alkaline suite grande cascade sequence monts dore french massif central have been investigated for evidence of mechanical magma mixing a wide variety of textures are present in the sequence as pillow like enclaves bandings and emulsified facies the grande cascade flows and pyroclasts range from basalt to trachyte 44 67 wt sio 2 pillow like enclaves intricate commingling and local diffusive mixing at the mafic felsic interface in emulsified types show that mafic inclusions were incorporated in their trachytic host as blobs of magma such inclusions were probably dispersed throughout the trachytic magma by mechanical mixing different stages of the evolution of a mechanical mixing process were recognized in relation with the stratigraphy and chronology of the products the most heterogeneous features enclaves bandings are restricted to the bottom of the sequence where basalt and trachyte coexist at the top texturally homogeneous trachyandesites occur relict phenocrysts are observed in both basaltic enclaves oligoclase fe rich clinopyroxene sanidine of the trachyte and trachytic hosts mg rich olivine mg rich clinopyroxene ca rich plagioclase of basalt the intermediate rocks basic trachyandesites contain xenocrysts of mg rich olivine clinopyroxenes oligoclase sanidine together with reversely zoned plagioclase and pyroxene phenocrysts this assemblage is presumed to result from the incorporation of xenocrysts related both to mafic and felsic endmembers all mineral assemblages are out of equilibrium reversed compositional zoning profiles in plagioclase and clinopyroxene crystals were produced by the mixing event we are able to identify the compositional characteristics of the components that were mixed a primary alkaline basalt mg olivine labrador mg clinopyroxene magnetite and a silicic trachyte oligoclase fe clinopyroxene sanidine are the endmembers of mixing observed chemical variations in major and trace elements can be modelled as pure binary mixtures between basaltic and trachytic endmembers using the best mixing line method provost and allegre 1979 the calculations emphasize that trachyandesites are the result of complete hybridization between basalt and trachyte the data on mesostasis show that melt mixing and not only crystal transfers has produced the intermediate lavas of the grande cascade sequence textural criteria petrography mineral chemistry and geochemical data major and trace elements support the magma mixing model

the influence of the madden julian oscillation on tropical cyclone activity in the fiji region abstract this study examines the modulation of tropical cyclone tc activity by the madden julian oscillation mjo in the fiji samoa and tonga regions fst region using joint typhoon warning center best track cyclone data and the mjo index developed by wheeler and hendon results suggest strong mjo tc relationships in the fst region the tc genesis patterns are significantly altered over the fst region with approximately 5 times more cyclones forming in the active phase than in the inactive phase of the mjo this modulation is further strengthened during el nino periods the large scale environmental conditions i e low level relative vorticity upper level divergence and vertical wind shear associated with tc genesis show a distinct patterns of variability for the active and inactive mjo phases the mjo also has a significant effect on hurricane category and combined gale and storm category cyclones in the fst region the occurrences of both these cyclone categories are increased in the active

geochemical provenance analyses of roman lava millstones north of the alps a study of their distribution and implications for the beginning of roman lava quarrying in the eifel region germany abstract in roman times rotary querns and different types of millstones driven either by horse capstan or water power were produced in the lava quarries of the quaternary volcanic eifel region and exported to many parts of the empire the geographic distribution of roman lava millstones from the eifel region provides important information about trade patterns and in cases of well dated millstones also allows an estimate as to when the roman lava quarrying in the eifel region began sixty two millstones from germany france and austria were sampled and analyzed for major and trace elements by x ray fluorescence to determine their provenance the millstone data was evaluated by a combination of geochemical discrimination and cluster and discriminant analyses using an extensive and detailed database of all roman lava quarries in the eifel region an eifel provenance could be confirmed for forty four artefacts and furthermore determined down to the exact lava flow the affiliation of the other artefacts to other possible regions where millstones of comparable lava were extracted was carried out on the basis of geochemical data from the literature however because of insufficient data only assumptions about the regional provenance can be made the origins of the other finds are assumed to be the vogelsberg region the massif central orvieto and possibly the pannonian basin a preliminary map of the distribution of eifel millstones in roman times based on these data is presented the beginning of roman lava quarrying can be constrained to 8 7 bc

magma mixing at la nugere volcano chaine des puys massif central france role in the trachyandesites genesis a succession of heterogeneous pyroclastites with contrasted composition hawaiite trachyte and homogeneous intermediate lava flows benmoreite is present at puy de la nugere chaine des puys massif central france mineralogical disequilibrium assemblages are present in both the explosive en effusive products textural mineralogical and geochemical data on these formations are compatible with a magma mixing model the origin of the trachyandesitic rocks in the alkaline suite of chaine des puys would be controlled by fractional crystallization and magma mixing

the madden julian oscillation s influence on african easterly waves and downstream tropical cyclogenesis abstractthe influence of the madden julian oscillation mjo over tropical africa and atlantic is explored during the northern hemisphere summer months the mjo is assessed by using real time multivariate mjo rmm indices these indices divide the active convective signal of the mjo into 8 phases convection associated with the mjo is enhanced over tropical africa during rmm phases 8 1 and 2 convection becomes suppressed over tropical africa during the subsequent rmm phases phases 3 7 african convective signals are associated with westward propagating equatorial rossby waves the mjo modulates african easterly wave aew activity aew activity is locally enhanced during rmm phases 1 3 and suppressed during rmm phases 6 8 enhanced aew activity occurs during periods of enhanced convection over tropical africa consistent with stronger or more frequent triggering of aews as well as more growth associated with latent heat release enhanced aew activity occurs during the low level westerly wind phase of

petrogenesis of monte vulture volcano italy inferences from mineral chemistry major and trace element data the paper presents major and trace element data and mineral compositions for a series of foiditic tephritic to phonolitic rocks coming from monte vulture southern italy and investigates their origin evolution and relationship with the other centres of the roman province

links between tropical cyclone activity and madden julian oscillation phase in the north atlantic and northeast pacific basins abstract the leading intraseasonal mode of atmospheric and oceanic variability the madden julian oscillation mjo influences tropical and extratropical sea level pressure temperature divergent and rotational wind components moisture and deep convection as a 40 to 50 day oscillation the mjo is also known to influence tropical phenomena including tropical cyclone tc activity in various tc basins the links between the mjo and multiple measures of tc activity including genesis landfall and an integrative accumulated cyclone energy ace index were quantified for multiple tc formation basins across the western hemisphere including the north atlantic and northeast pacific ocean and subbasins for the period 1978 2006 using this relatively long 29 yr tc dataset and employing an upper tropospheric mjo diagnostic that is physically meaningful over the entire western hemisphere this study extends existing research on the relationships between the mjo and tcs the noaa climate prediction cente

geochemistry and trade of eastern mediterranean millstones from the neolithic to roman periods millstones and grindstones of the prehistoric to roman periods include saddle querns rectangular hopper rubber mills rotary querns and pompeian style donkey mills many of these were manufactured from igneous rocks which can be provenanced to their geological sources using chemical analysis giving information about trade contacts of sites sixty nine samples of 10 20 g each were removed from broken parts of lava millstones of prehistoric and early historic date from sites in israel syria egypt greece and turkey these were analysed for major and trace elements using x ray fluorescence and petrological features were examined in thin section the millstones were all young generally fresh lavas ranging from vesicular basalt to porphyritic andesite potential sources occur in younger volcanics of mainland greece the aegean turkey and the levant israel syria and jordan and in egypt thirty four geological samples from israel syria and turkey were collected and analysed in the same way as the archaeological samples and an intensive literature survey carried out to supplement these by published analyses comparison of archaeological samples with source data is done by using a series of discrimination graphs following a simple flow diagram the archaeological samples were of two types within plate lavas and island arc or other subduction related lavas all samples were successfully assigned to sources and results show use of the source areas as follows during the prehistoric period neolithic bronze age pre 6th century bc iron age samples saddle querns in mainland greece were made of aegina andesire while sites in north syria used local syrian lavas and in israel basalts from near lake tiberias and from the dead sea area were used earlier work by the authors and others has shown import of levant millstones to cyprus in the late bronze age hopper rubbers of the 5th century bc onwards were made at specialized quarries in aegean islands on nisyros kimolos and santorini and exported to mainland greece western turkey egypt and cyprus less well finished hopper rubbers were made and used in western turkey and in israel roman pompeian style mills were made of levant lavas from several sources particularly around lake tiberias and were transported within israel as well as to cyprus as shown by earlier studies rotary querns were made of lavas from santorini and probably nisyros and of locally used west anatolian rocks rotary querns of roman and later 10th 12th century ad dates were also produced at several sources in the levant again around lake tiberias and probably in north syria and within the dead sea volcanics for use within israel olive crushing trapeta used in turkey and greece were manufactured from andesites from anatolia and aegina respectively west anatolian lavas mill types unknown have also been identified at roman sites in the eastern desert of egypt millstone distributions increased in complexity and extent over time with hopper rubbers being traded up to 820 km from sources and roman rotary millstones up to 1300 km the three major source areas aegean anatolia and the levant were in apparent competition by the roman period when there is extensive overlap of distributions from different sources with aegean and anatolian products traded the furthest the millstone trade in the eastern mediterranean is separate from that of the west mediterranean west of greece except for one hopper rubber of nisyros lava identified in a shipwreck off mallorca this dichotomy is in marked contrast to the distribution of amphorae within which west mediterranean italian products were widely used in the east from at least the 2nd century bc stylistically east mediterranean millstones also show differences from those in the west in the prevalence of hopper rubbers and later in decorative features common on pompeian style mills

theory of synthetic aperture radar ocean imaging a marsen view this paper reviews basic synthetic aperture radar sar theory of ocean wave imaging mechanisms using both known work and recent experimental and theoretical results from the marine remote sensing marsen experiment several viewpoints that have contributed to the field are drawn together in a general analysis of the backscatter statistics of a moving sea surface a common focus for different scattering models is provided by the mean image impulse response function which is shown to be identical to the spatially varying frequency variance spectrum of the local complex reflectivity coefficient from the analysis has emerged a more complete view of the sar imaging phenomenon than has been previously available a new generalized imaging model is proposed

modulation of hurricane activity in the gulf of mexico by the madden julian oscillation the madden julian oscillation mjo is a large scale episodic modulation of tropical winds and precipitation that travels eastward from asia to america with a characteristic repeat time of 30 to 60 days here it is shown that when mjo wind anomalies in the lower troposphere of the eastern pacific are westerly gulf of mexico and western caribbean hurricane genesis is four times more likely than when the mjo winds are easterly accurate predictions of the mjo may lead to improved long range forecasts of tropical cyclone activity

tower ocean wave and radar dependence experiment a synthesis the tower ocean wave and radar dependence experiment toward was conceived to provide an experimental data base to resolve the disparity among the different synthetic aperture radar sar imaging theories of the ocean surface this goal has been achieved through publication of two collections of scientific papers of which the second is part of this issue there is now a framework and consensus on how sar images the ocean surface

modulation of tropical cyclogenesis location and frequency over the indo western north pacific by the intraseasonal indo western pacific convection oscillation during the boreal extended summer abstractthe influence of the intraseasonal indo western pacific convection oscillation ipco on tropical cyclone tc genesis location and frequency over the indo western north pacific wnp during the boreal extended summer may october is explored observational analysis shows that the impacts of the intraseasonal ipco on tcs over the indo wnp include an evident phase lock of tc genesis location and distinct differences in tc frequency in the wnp in the positive intraseasonal ipco phase the atmosphere gains heat through the release of latent heat in cumulus convective condensation and the anomalous cyclonic circulation weakens the western pacific subtropical high wpsh and enhances tc genesis thereby tending to produce many more tcs moreover the diminished wpsh and the westward shift of the centers of anomalous cyclonic circulations lock tc genesis locations to the west wnp and lower latitudes around 5 20 n especially in the south china sea the almost opposite situation occurs in a nega

roman lava quarries in the eifel region germany geochemical data for millstone provenance studies roman millstones of assumed eifel origin were produced and exported in huge quantities to many parts of roman europe and can be used as tracers for trade patterns in roman times this study presents for the first time a raw material centred geochemical definition of the 13 well known roman basaltic lava quarries in the quaternary east and west eifel volcanic fields the aim is to find a way to characterize the individual exploitation sites precisely by means of their geochemical composition and to recommend a standard procedure for further millstone provenance analysis based on major and trace element composition analyses by xrf a differentiation of each quarry is achieved by using a combination of geochemical discrimination and cluster and discriminant analysis therefore for provenance analysis of a unknown millstone sample the following procedure is recommended 1 geochemical discrimination to check if it actually belongs to the volcanic eifel quarries 2 cluster analysis to check to which quarry or cluster of quarries the millstone can be affiliated and 3 discriminant analysis to assign the sample to its quarry of origin with a certain confidence

three dimensional structure and evolution of the mjo and its relation to the mean flow abstractthe two leading principal components of the daily 850 minus 150 hpa global velocity potential in the interim european centre for medium range weather forecasts ecmwf re analysis era interim 1979 2011 data are used as time varying madden julian oscillation mjo indices regression maps and meridional cross sections based on these indices are used to document the structure and evolution of the zonal wind u and geopotential height z anomalies in the mjo cycle the data are daily and they are not separated by season at upper tropospheric levels the mjo signature is dominated by eastward propagating planetary wave packets consisting of equatorial kelvin waves flanked by rossby waves centered along 28 n s for which the westerly jet streams serve as waveguides at lower tropospheric levels the pattern more closely resembles the response to a pulsating heat source over the maritime continent where the andes block the eastward propagating kelvin wave pulse the contrasting upper and lower

magma evolution at mount vulture southern italy the vulture complex is made up of foiditic tephritic phonolitic trachytic and phonolitic products new rock analyses have been performed in order to ascertain whether the various rock types derive from a unique parental magma and if so to define its nature the data presented support that the vulture suite originated from a foiditic melt which had differentiated at low pressures the main process determining the foidite tephrite phonolitic trachyte evolution seems to be the crystal fractionation of mainly clinopyroxenes and opaques with the contribution of plagioclases and hauyne too in the tephrite trachyte evolution additionary role must have been played by a mixing of melts at different evolution stages occurred in a shallow seated magma chamber

the zonal dipole pattern of tropical cyclone genesis in the indian ocean influenced by the tropical indo pacific ocean sea surface temperature anomalies abstractfrom a basinwide perspective the dominant mode of indian ocean tropical cyclone genesis tcg in september november son shows an equatorially symmetric east west zonal dipole pattern wh

improved extended reconstruction of sst 1854 1997 abstract an improved sst reconstruction for the 1854 1997 period is developed compared to the version 1 analysis in the western tropical pacific the tropical atlantic and indian oceans more variance is resolved in the new analysis this improved analysis also uses sea ice concentrations to improve the high latitude sst analysis and a modified historical bias correction for the 1939 41 period in addition the new analysis includes an improved error estimate analysis uncertainty is largest in the nineteenth century and during the two world wars due to sparse sampling the near global average sst in the new analysis is consistent with the version 1 reconstruction the 95 confidence uncertainty for the near global average is 0 4 c or more in the nineteenth century near 0 2 c for the first half of the twentieth century and 0 1 c or less after 1950

cluster analysis of tropical cyclone tracks in the southern hemisphere a probabilistic clustering method is used to describe various aspects of tropical cyclone tc tracks in the southern hemisphere for the period 1969 2008 a total of 7 clusters are examined three in the south indian ocean three in the australian region and one in the south pacific ocean large scale environmental variables related to tc genesis in each cluster are explored including sea surface temperature low level relative vorticity deep layer vertical wind shear outgoing longwave radiation el nino southern oscillation enso and the madden julian oscillation mjo composite maps constructed 2 days prior to genesis show some of these to be significant precursors to tc formation most prominently westerly wind anomalies equatorward of the main development regions clusters are also evaluated with respect to their genesis location seasonality mean peak intensity track duration landfall location and intensity at landfall enso is found to play a significant role in modulating annual frequency and mean genesis location in three of the seven clusters two in the south indian ocean and one in the pacific the enso modulating effect on genesis frequency is caused primarily by changes in low level zonal flow between the equator and 10 s and associated relative vorticity changes in the main development regions enso also has a significant effect on mean genesis location in three clusters with tcs forming further equatorward poleward during el nino la nina in addition to large shifts in mean longitude the mjo has a strong influence on tc genesis in all clusters though the amount modulation is found to be sensitive to the definition of the mjo

on the madden julian oscillation atlantic hurricane relationship abstract the large scale equatorial circulation known as the madden julian oscillation mjo has been shown to impact tropical cyclone activity in several basins around the globe in this paper the author utilizes an mjo index created by wheeler and hendon to examine its impacts on tropical genesis and intensification in the atlantic large differences in frequency and intensity of tropical cyclone activity are seen both in the tropical atlantic as well as in the northwest caribbean and gulf of mexico depending on the mjo phase coherent changes in upper and lower level winds and relative humidity are likely responsible for these differences since the mjo shows potential predictability out to about two weeks the relationships discussed in this paper may be useful for short term predictions of the probability of tropical cyclone activity in the atlantic as a complement to the already available longer term seasonal predictions

potential vorticity easterly waves and eastern pacific tropical cyclogenesis abstract a significant sign reversal in the meridional potential vorticity gradient was found during the summer of 1991 on the 310 k isentropic surface near 700 mb over the caribbean sea the charney stern necessary condition for instability of the mean flow is met in this region it is speculated that the sign reversal permits either invigoration of african waves or actual generation of easterly waves in the caribbean during the same season a correlation existed between the strength of the negative potential vorticity gradient in the caribbean and subsequent cyclogenesis in the eastern pacific the meridional pv gradient convective heating measured by outgoing longwave radiation data and eastern pacific cyclogenesis all varied on the timescale of the madden julian oscillation mjo it is hypothesized that upstream wave growth in the dynamically unstable region provides the connection between the mjo or any other convective forcing and the associated enhanced downstream tropical cyclogenesis

an anomalous genesis potential index for mjo modulation of tropical cyclones abstractmodulation of tropical cyclone tc genesis by the madden julian oscillation mjo has been quantitatively diagnosed by using a climatological genesis potential index gpi analysis of tc genesis during november april of 1979 2014 indicates the most effective factors controlling intraseasonal tc genesis are 850 hpa relative vorticity weighted by the coriolis parameter f r850 and 500 hpa vertical motion 500 the total vertical wind shear and maximum potential intensity are unimportant and the role of 600 hpa relative humidity is greatly represented by 500 the mjo modulates tc genesis primarily through changing low level vorticity induced by its rossby wave gyres and meridional shears of equatorial zonal winds a new intraseasonal gpi isgpi is proposed to quantify the mjo s modulation of tc genesis the isgpi significantly improves representation of intraseasonal variation of tc genesis in the tropics and in each subregion of the southern indian ocean australian monsoon and south pacific i

lateral flow of african mantle below the nearby tyrrhenian plate geochemical evidence the quaternary magmatism of the southern tyrrhenian basin represents a rare example of an active volcanic arc system where ocean island basalt oib and island arc basalt iab magmas coexist although there is general agreement on the importance of the ionian oceanic lithosphere subduction in the genesis of the iab magmatism the tectono magmatic processes producing the coexisting oib magmas are still poorly understood here we show that the geochemistry of the quaternary southern tyrrhenian oib type magmatism i e ustica island and prometeo a previously unknown submarine lava field is very similar to that of oib type volcanoes situated on the nearby african plate i e etna and hyblean plateau among the possible geodynamic scenarios proposed to explain the coexistence of oib and iab magmas in arc settings we consider the development of a tear at the edge of the ionian plate as the more likely mechanism to favour the flow of african asthenospheric mantle below the tyrrhenian plate

mediterranean trade of the most widespread roman volcanic millstones from italy and petrochemical markers of their raw materials abstract the petrochemical study of millstones can contribute to improve the archaeological research into reconstruction of ancient communication routes and trade networks volcanic rocks are geographically restricted and rather rare in the mediterranean regions and during the roman period italian volcanoes were important sources of raw materials for millstones so the task of determining their geological origin is relatively straightforward the italian vesicular volcanics most frequently employed for this purpose were trachytes from euganean hills veneto leucite bearing lavas from the vulsini volcanic district latium basic intermediate leucite bearing lavas from somma vesuvius campania silica undersaturated lavas from monte vulture volcano basilicata a rhyolitic ignimbrite from sardinia and basic products from mount etna and the island of pantelleria sicily this paper contains a general outline of the trade network for each volcanic typology used for millstones during the roman period updated with data concerning the leucite bearing lavic items discovered in the archaeological sites of the ancient cuicul now djemila algeria together with a summary of their petrographic and geochemical features

sem eds characterization of western mediterranean obsidians and the neolithic site of a fuata corsica during the neolithic obsidians of the monte arci sardinia volcanic complex were by far more used in the northern tyrrhenian area than those of the three other source islands lipari palmarola pantelleria in the western mediterranean it is shown that merely determinations of content for six major elements with a scanning electron microscope by energy dispersion spectrometry sem eds are sufficient to distinguish the four types of monte arci obsidians because of the compositional similarities between these obsidian types a multivariate analysis is recommended in provenance studies although sem eds electron microprobe wavelength dispersion spectrometry emp wds and particle induced x ray emission pixe give essentially concordant results in the determination of these six element contents subtle technique related biases prevent the combination of sem eds emp wds and pixe data on source samples for provenance purposes an sem eds test study reveals the first occurrence of obsidians of lipari for the a fuata middle to late neolithic site of nw corsica north of sardinia in addition to the usual monte arci obsidians similar to emp wds the sem eds technique requires only millimeter sized fragments

on the focusing issue of synthetic aperture radar imaging of ocean waves it is widely accepted that the imaging of ocean surface waves by synthetic aperture radar sar can be adequately described by velocity bunching theory in conjunction with the two scale wave model however it has been conjectured that this theory is incapable of explaining why under certain conditions the image contrast of airborne sar imagery of ocean waves can be enhanced by defocusing the sar processor in the present study the velocity bunching theory is defended

role of multiple equatorial waves on cyclogenesis over bay of bengal tropical variations on intraseasonal time scales like madden julian oscillations mjo tropical depressions and convectively coupled equatorial waves ccews are known to modulate the probability of cyclogenesis over different ocean basins in the present study a detailed analysis of the role of mjo kelvin waves equatorial rossby er waves and combined mixed rossby gravity waves and tropical depressions mt on cyclogenesis over the bay of bengal bob is carried out for a period of 1979 2013 the effect of different waves occurring individually and their combinations on the cyclogenesis over bob is studied it is shown that the cyclogenesis is favoured over bob when multiple waves are present simultaneously than in the presence of a single wave individually er is most favourable for the cyclogenesis followed by mjo while mt is the least favourable a combination of er and mjo is associated with the highest number of cyclogenesis and the least number of cyclones are formed when kelvin and mt are present together modulation of the atmospheric factors contributing to the cyclogenesis potential namely vorticity relative humidity rh and vertical wind shear by different waves is discussed it is shown that the mjo increases the cyclogenesis by increasing rh while the rossby wave contributes by increasing the relative vorticity and mt contributes by reducing the vertical wind shear on the other hand mt has the least rh while kelvin wave is associated with the least vorticity thus contributing to lesser number of cyclogenesis