eddy diffusivities estimated from observations in the labrador sea eddy diffusivities in the labrador sea ls are estimated from deep eddy resolving float trajectories moored current meter records and satellite altimetry a mean residence time of 248 days in the central ls is observed with several floats staying for more than 2 years by applying a simple random walk diffusion model the observed distribution of float residence times in the central ls could be explained by a mean eddy diffusivity of about 300 m2 s 1 estimates from float trajectories themselves and from moored current meter records yield significantly higher eddy diffusivities in the central ls of 950 1100 m2 s 1 this discrepancy can be explained by an inhomogeneity of the eddy diffusivity at middepth with high low values in the central ls region between central ls and deep labrador current which could be conjectured from the mean altimetric eddy kinetic energy eke distribution the different diffusivities explain both 1 a fast lateral homogenization of water masses in the central ls and 2 a weak exchange between central ls and boundary current the mean lagrangian length scale of 11 5 0 7 km as estimated from deep float trajectories is only slightly larger than the mean rossby radius of deformation 8 8 km largest eddy diffusivities within the central ls are associated with strong eddy drifts rather than with large swirl velocities and associated large eke between central ls and deep labrador current which could be conjectured from the mean altimetric eddy kinetic energy eke distribution the different diffusivities explain both 1 a fast lateral homogenization of water masses in the central ls and 2 a weak exchange between central ls and boundary current the mean lagrangian length scale of 11 5 0 7 km as estimated from deep float trajectories is only slightly larger than the mean rossby radius of deformation 8 8 km largest eddy diffusivities within the central ls are associated with strong eddy drifts rather than with large swirl velocities and associated large eke

airborne biogeophysical mapping of hidden mineral deposits three mapping surveys of cotter basin montana and spirit lake washington the tree cover with widespreading and deeply penetrating root systems is turned to an advantage in the airborne biogeophysical technique by detecting metal induced changes in the chlorophyll reflectance spectrum modified journal abstract

chronological sequence of the early pleistocene gigantopithecus faunas from cave sites in the chongzuo zuojiang river area south china abstract since 2004 five new early pleistocene cave sites with gigantopithecus blacki and other fossil mammals have been discovered in the chongzuo zuojiang river area guangxi zhuang autonomous region guangxi zar south china these sites include baikong cave of liyu mountain juyuan cave of boyue mountain sanhe and queque caves of wuming mountain and wuming cave of mulan mountain the present study provides a preliminary account of these newly discovered gigantopithecus faunas and discusses their taxonomic composition evolutionary trends and chronology based on recent biostratigraphic and geochronological studies combining faunal and paleomagnetic data the gigantopithecus faunas from the zuojiang river area can be divided into three temporal stages during the early pleistocene the early stage 2 6 1 8 ma is represented by the baikong and boyue faunas which include some neogene relics e g sinomastodon hesperotherium dicoryphochoerus dorcabune and cervavitus and several species that make their first appearance during the pleistocene e g sinicuon dubius pachycrocuta licenti ailuropoda microta sinomastodon jiangnanensis stegodon huananensis and tapirus sanyuanensis the middle stage 1 8 1 2 ma is represented by the sanhe fauna which is characterized by the appearance of ailuropoda wulingshanensis cuon antiquus and tapirus sinensis the late stage 1 2 0 8 ma is represented by the queque fauna which is characterized by a marked decrease in neogene relics and the appearance of a few species that are more typical of the middle pleistocene e g ailuropoda baconi and stegodon orientalis evolutionary trends in the early pleistocene gigantopithecus faunas include a gradual increase in dental size in some of the typical taxa such as g blacki ailuropoda and tapirus and the successive turnover of representative species such as a microta a wulingshanensis a baconi thus far eleven g blacki sites of early pleistocene age have been recorded in southern china and these are primarily concentrated in guangxi zar where more than 70 of early pleistocene g blacki cave sites are known given this temporal and geographic distribution it is possible to infer that guangxi zar represents an important early evolutionary and zoogeographic center for g blacki

suppression of eddy diffusivity across jets in the southern ocean abstract geostrophic eddies control the meridional mixing of heat carbon and other climatically important tracers in the southern ocean the rate of eddy mixing is typically quantified through an eddy diffusivity there is an ongoing debate as to whether eddy mixing in enhanced in the core of the antarctic circumpolar current or on its flanks a simple expression is derived that predicts the rate of eddy mixing that is the eddy diffusivity as a function of eddy and mean current statistics this novel expression predicts suppression of the cross jet eddy diffusivity in the core of the antarctic circumpolar current despite enhanced values of eddy kinetic energy the expression is qualitatively and quantitatively validated by independent estimates of eddy mixing from altimetry observations this work suggests that the meridional eddy diffusivity across the antarctic circumpolar current is weaker than presently assumed because of the suppression of eddy mixing by the strong zonal current

anomalies on geologic maps from multispectral and textural classification the bleida mining district morocco the variogram analysis of different reference image facies on a spot xs scene enables the definition of a discriminant texture index the values of this index are extracted locally in a given neighborhood this textural information is matched with the multispectral information in order to realize a combined classification the result is subsequently compared to a digitized geological map in order to extract zones of anomaly regarded as the differences between the combined classification and the geological map a majority of the anomalies require further interpretation while certain others are interesting to mineral prospecting

rationalizing the spatial distribution of mesoscale eddy diffusivity in terms of mixing length theory observations and theory suggest that lateral mixing by mesoscale ocean eddies only reaches its maximum potential at steering levels surfaces at which the propagation speed of eddies approaches that of the mean flow away from steering levels mixing is strongly suppressed because the mixing length is smaller than the eddy scale thus reducing the mixing rates the suppression is particularly pronounced in strong currents where mesoscale eddies are most energetic here a framework for parameterizing eddy mixing is explored that attempts to capture this suppression an expression of the surface eddy diffusivity proposed by ferrari and nikurashin is evaluated using observations of eddy kinetic energy eddy scale and eddy propagation speed the resulting global maps of eddy diffusivity have a broad correspondence with recent estimates of diffusivity based on the rate at which tracer contours are stretched by altimetric derived surface currents finally the expression for the eddy diffusivity is extrapolated in the vertical to infer the eddy induced meridional heat transport and the overturning streamfunction

inferring circulation and lateral eddy fluxes in the arctic ocean s deep canada basin using an inverse method abstractthe deep waters in the canada basin display a complex temperature and salinity structure the evolution of which is poorly understood the fundamental physical processes driving changes in

shuttle imaging radar experiment the shuttle imaging radar sir a acquired images of a variety of the earth s geologic areas covering about 10 million square kilometers structural and geomorphic features such as faults folds outcrops and dunes are clearly visible in both tropical and arid regions the combination of sir a and seasat images provides additional information about the surface physical properties topography and roughness ocean features were also observed including large internal waves in the andaman sea

the taphonomy and palaeoenvironmental implications of the small mammals from karain cave turkey the small mammal accumulations in the pleistocene deposits of karain cave are investigated to identify the predators and possible biases in the fossil assemblages seven small mammal assemblages are studied in chronological order from two chambers of the cave the main chamber e and the side chamber b the lowermost level within the whole sequence is proto charentien which corresponds to an early stage of the middle palaeolithic the main part of the material belongs to middle palaeolithic layers the most important aspect of the fossil record in the cave is the human occupation without any interruption through the pleistocene to holocene the small mammal fossil evidence in the cave denotes the presence of opportunistic predators throughout the sequence with one exception and these produce balanced samples of small mammal faunas in the habitat the lack of bias in the small mammal faunas allow the interpretation of local environments showing that partial steppe and arid conditions existed during deposition of the lowermost levels of the middle palaeolithic in karain cave and that these shifted into more temperate and wooded habitat in the upper levels evidence from the side chamber indicates some differences with a more open grassy environment in the mediterranean part of anatolia the temperate and moist conditions in the middle palaeolithic were superseded by more arid conditions in the upper palaeolithic followed by a decrease in steppe conditions during the epi palaeolithic period

estimating eddy stresses by fitting dynamics to observations using a residual mean ocean circulation model and its adjoint a global ocean circulation model is formulated in terms of the residual mean and used to study eddy mean flow interaction adjoint techniques are used to compute the three dimensional eddy stress field that minimizes the departure of the coarse resolution model from climatological observations of temperature the resulting 3d maps of eddy stress and residual mean circulation yield a wealth of information about the role of eddies in large scale ocean circulation in eddy rich regions such as the southern ocean the kuroshio and the gulf stream eddy stresses have an amplitude comparable to the wind stress of order 0 2 n m 2 and carry momentum from the surface down to the bottom where they are balanced

isopycnal eddy diffusivities and critical layers in the kuroshio extension from an eddying ocean model abstracthigh spatial resolution isopycnal diffusivities are estimated in the kuroshio extension ke region 28 40 n 120 190 e from a global parallel ocean program pop simulation the numerical float tracks are binned using a clustering approach the number of tracks in each bin is thus roughly the same leading to diffusivity estimates that converge better than those in bins defined by a regular geographic grid cross stream diffusivities are elevated in the southern recirculation gyre region near topographic obstacles and downstream in the ke jet where the flow has weakened along stream diffusivities which are much larger than cross stream diffusivities correlate well with the magnitudes of eddy velocity the ke jet suppresses cross stream mixing only in some longitude ranges this study estimates the critical layer depth both from linear local baroclinic instability analysis and from eddy phase speeds in the pop model using the radon transform the latter is a better predictor of large mixi

evaluation of the potential of surface pollen spectra from caves in sw china for vegetation reconstruction abstract pollen analysis is rarely applied to cave sediments because of the complex range of processes influencing the origin transport and taphonomy of pollen grains in caves in order to evaluate the potential of pollen spectra from within caves for vegetation reconstruction we compared the modern pollen from the interior and exterior of four caves in guangxi and guizhou in southwestern china the results show that the pollen spectra from within the sack shaped caves and from the front and middle of a long narrow caves were similar to those outside the caves and therefore that the pollen spectra from these caves can reliably be used for palaeovegetation reconstruction wind is the major transport medium for the pollen entering caves but animals may be additional transport medium in addition cave geometry is likely to be responsible for the observed spatial distribution of pollen concentrations in caves in long narrow caves the entrance is the optimum sampling location for pollen analysis however in sack shaped caves an optimum sampling location cannot be specified due to the gradient in pollen concentration between the entrance and the rear together with its irregular distribution

oxygen tongues and zonal currents in the equatorial atlantic 1 equatorial zonal currents and associated oxygen distributions are studied using shipboard hydrographic data trajectories from isopycnic floats drifting at about 300 m depth and velocity time series from the upper 1100 m obtained at two equatorial moorings located at 35 w and 23 w mean profiles of zonal velocity measured by moored acoustic doppler current profilers yielded a westward flowing equatorial intermediate current eic below the equatorial undercurrent euc at both locations the eic consists of two westward current cores at about 250 and 450 m the upper core of the eic deepens by about 30 m from 23 w where it has a mean velocity of 6 2 cm s 1 to 35 w where the mean is 5 3 cm s 1 the lower core of the eic is about twice as strong with 12 1 cm s 1 at 23 w and 9 2 cm s 1 at 35 w the flow below the euc is characterized by substantial interannual variability from may to december 2005 a strong zonally coherent eastward jet occurred at 300 to 350 m depth found to be an expression of shallow stacked jets superimposed on the mean eic shipboard hydrographic observations in june july 2006 revealed the existence of a high oxygen tongue that can be traced from 35 w to 10 w in the depth range of the eastward jet prevailing during the preceding year on the basis of an advection diffusion balance it is suggested that the oxygen decrease from 35 w to 10 w within the oxygen tongue is mainly balanced by lateral eddy diffusivity and oxygen consumption with diapycnal turbulent diffusivity playing only a minor role

estimating suppression of eddy mixing by mean flows particle and tracer based estimates of lateral diffusivities are used to estimate the suppression of eddy mixingacrossstrongcurrents particlesandtracersare advectedusingavelocityfieldderivedfromseasurface height measurements from the south pacific in a region west of drake passage this velocity field has been used in a companion paper to show that both particle and tracer based estimates of eddy diffusivities are equivalent despite recent claims to the contrary these estimates of eddy diffusivities are here analyzed to show 1 that the degree of suppression of mixing across the strong antarctic circumpolar current is correctly predicted by mixing length theory modified to include eddy propagation along the mean flow and 2 that the suppressioncan beinferredfromparticletrajectoriesby studyingthestructureofthe autocorrelationfunction of the particle velocities beyond the first zero crossing these results are then used to discuss how to compute lateral and vertical variations in eddy diffusivities using floats and drifters in the real ocean

magnetochronological sequence of the early pleistocene gigantopithecus faunas in chongzuo guangxi southern china abstract the gigantopithecus fauna the most important mammalian fauna during the early pleistocene in southern china was usually excavated from cave or fissure deposits without precise age constraints here we present new magnetostratigraphy results for four cave sedimentary sequences in chongzuo guangxi zhuang autonomous region of southern china from the highest and oldest to the lowest and youngest including baikong cave juyuan cave sanhe cave and queque cave magnetite was identified as the major carrier of characteristic remnant magnetizations in the cave deposits correlation to the geomagnetic polarity time scale was achieved by combining magnetostratigraphic and biochronologic data our correlation suggests that the cave sedimentary sequences span from the pre olduvai matuyama chron to the jaramillo subchron the combined magneto biochronology leads to the establishment of a chronological framework for the early pleistocene gigantopithecus faunas in chongzuo area the gigantopithecus faunal succession of early pleistocene were assigned to estimated ages of 2 0 ma baikong cave 1 8 ma juyuan cave 1 2 ma sanhe cave and 1 0 ma queque cave respectively the river incision rate in chongzuo area during this time span was estimated to be 14 mm ky

the coexistence approach a method for quantitative reconstructions of tertiary terrestrial palaeoclimate data using plant fossils abstract the coexistence approach is introduced as a method for quantitative terrestrial palaeoclimate reconstructions in the tertiary it is based on the assumption that tertiary plant taxa have similar climatic requirements to their nearest living relatives the aim of the coexistence approach is to find for a given fossil flora and a given climate parameter the climatic interval in which all nearest living relatives of the fossil flora can coexist for this purpose we have developed a data base climbot containing for over 800 tertiary plant taxa the nearest living relatives and their climatic requirements and an algorithm for analysis climst for all types of fossil floras the coexistence approach thus allows the rapid quantitative reconstruction of 10 different climate parameters including the mean annual temperature temperature of the warmest month temperature of the coldest month mean annual precipitation maximum monthly precipitation minimum monthly precipitation precipitation of the warmest month relative humidity potential evaporation as well as the ratio of mean annual precipitation over potential evaporation the reliability and resolution of the coexistence approach are tested with various techniques and proved to be reasonably good for instance the resolution with respect to the mean annual temperature can be up to 1 c applications to various modern and fossil floras are illustrated and the advantages and disadvantages of the coexistence approach are discussed

multipolarization radar images for geologic mapping and vegetation discrimination the nasa jpl airborne synthetic aperture radar system produces radar image data simultaneously in four linear polarizations hh vv vh hv at 24 6 cm wavelength l band with 10 m resolution across a swath width of approximately 10 km the signal data are recorded optically and digitally and annotated in each of the channels to facilitate a completely automated digital correlation both standard amplitude and also phase difference images are produced in the correlation process individual polarization and range dependent gain functions improve the effective dynamic range but as yet do not permit absolute quantitative measurements of the scattering coefficients however comparison of the relative intensities of the different polarizations in individual black and white and color composite images provides discriminatory mapping information in the death valley california area rough surfaces of young alluvial deposits produce strong responses at all polarizations smoother surfaces of older alluvial deposits show significantly lower responses evaporite deposits of different types and moisture contents have distinct polarization signatures in the wind river basin wyoming sedimentary rock units show polarization responses that relate to differences in weathering local intensity variations in like polarization images result from topographic effects strong cross polarization responses denote the effects of vegetation cover and in some cases possible scattering from the subsurface in the savannah river plant south carolina forest cover characteristics are discriminated by polarization responses that reflect the density and structure of the canopy and the presence or absence of standing water beneath the canopy

weak mixing in the eastern north atlantic an application of the tracer contour inverse method abstract the tracer contour inverse method is used to infer mixing and circulation in the eastern north atlantic solutions for the vertical mixing coefficient d the along isopycnal mixing coefficient k and a geostrophic streamfunction are all direct outputs of the method the method predicts a vertical mixing coefficient o 10 5 m2 s 1 in the upper 1000 m of the water column consistent with in situ observations the method predicts a depth dependent along isopycnal mixing coefficient that decreases from o 1000 m2 s 1 close to the mixed layer to o 100 m2 s 1 in the interior which is also consistent with observations and previous hypotheses the robustness of the result is tested with a rigorous sensitivity analysis including the use of two independently constructed datasets this study confirms the utility of the tracer contour inverse method the results presented support the hypothesis that vertical mixing is small in the thermocline of the subtropical atlantic ocean a strong depth dependence o

water mass transformation by cabbeling and thermobaricity water mass transformation is an important process for the global ocean circulation nonlinearities in the equation of state of seawater lead to water mass transformation due to cabbeling and thermobaricity here the contribution of cabbeling and thermobaricity to water mass transformation is calculated in a neutral density framework using temperature gradients derived from observationally based gridded climatologies and observationally based estimates of the spatially varying eddy diffusivities it is shown that cabbeling and thermobaricity play a significant role in the water mass transformation budget with cabbeling having a particularly important role in the formation of antarctic intermediate water and antarctic bottom water a physical hypothesis is presented which explains why cabbeling is important for antarctic intermediate water formation it is shown that spatially varying estimates of eddy diffusivities are essential to correctly quantify the role of cabbeling to the formation of antarctic intermediate water

geographical variability of the first baroclinic rossby radius of deformation global 1 83 18 climatologies of the first baroclinic gravity wave phase speed c1 and the rossby radius of deformation l1 are computed from climatological average temperature and salinity profiles these new atlases are compared with previously published 5 83 58 coarse resolution maps of l1 for the northern hemisphere and the south atlantic and with a 1 83 18 fine resolution map of c1 for the tropical pacific it is concluded that the methods used in these earlier estimates yield values that are biased systematically low by 5 15 owing to seemingly minor computational errors geographical variations in the new high resolution maps of c1 and l1 are discussed in terms of a wkb approximation that elucidates the effects of earth rotation stratification and water depth on these quantities it is shown that the effects of temporal variations of the stratification can be neglected in the estimation of c1 and l1 at any particular location in the world ocean this is rationalized from consideration of the wkb approximation

seasonal evolution of upper ocean horizontal structure and the remnant mixed layer 1 we discuss the seasonal evolution of upper ocean thermohaline structure at small horizontal scales the upper 350 m of a 1000 km long section in the subtropical north pacific was observed in winter spring and summer with 3 14 km horizontal resolution four vertical regions had distinct density and salinity structure the mixed layer remnant mixed layer high stratification layer and permanent thermocline the remnant mixed layer consists of water from the winter mixed layer left over after restratification the remnant mixed layer was most similar to the mixed layer in winter and spring and most similar to the high stratification layer below in summer the high stratification layer had elevated stratification that varied seasonally the permanent thermocline varied little seasonally and was horizontally and vertically uniform in comparison in all seasons density ratios showed that mixed layer s differences tended to compensate in density with the strongest tendency toward compensation in winter density ratios were temperature dominated in the remnant mixed layer consistent with salt fingering salinity anomalies were largest at the surface and decayed with depth in all seasons spectra of isopycnal depth and s anomalies along isopycnals are compared between the three seasons and four vertical layers isopycnal depth variance at 30 46 km wavelengths decreased from winter to spring to summer by a factor of 2 10 in stratified regions by treating salinity anomalies as a tracer the effective isopycnal diffusivity in the remnant mixed layer was estimated to be 1 4 m2 s 1 over 30 46 km wavelengths

palynological analysis of the late early pleistocene sediments from queque cave in guangxi south china abstract palynomorphs extracted from the sediments in queque cave of the late early pleistocene in chongzuo guangxi zhuang autonomous region were investigated to reconstruct the paleoenvironment in the study area while the sediments are pollen poor they are sufficiently productive to carry out a paleoenvironmental analysis the source vegetation reflected by the palynomorphs from the unfossiliferous layer was temperate to warm temperate deciduous and evergreen broadleaved forest while it was warm temperate to subtropical deciduous and evergreen broadleaved forest from the mammalian horizons climatic parameters obtained using the coexistence approach indicate that the unfossiliferous layer mat 11 3 15 4 c map 601 1 1076 1 mm was cooler and drier than that from the mammal bearing layers mat 12 6 18 6 c map 784 7 1523 1 mm

global surface eddy diffusivities derived from satellite altimetry 1 velocities derived from aviso sea surface height observations adjusted to be nondivergent are used to simulate the evolution of passive tracers at the ocean surface eddy mixing rates are derived from the tracer fields in two ways first the method of nakamura is applied to a sector in the east pacific second the osborn cox diffusivity is calculated globally to yield estimates of diffusivity in two dimensions the results from the east pacific show weak meridional mixing at the surface in the southern ocean 1000 m2 s 1 consistent with previous results but higher mixing rates 3000 5000 m2 s 1 in the tropical ocean the osborn cox diagnostic provides a global picture of mixing rates and agrees reasonably well with the results from the east pacific it also shows extremely high mixing rates 104 m2 s 1 in western boundary current regions the osborn cox diffusivity is sensitive to the tracer initialization which we attribute to the presence of anisotropic mixing processes the mixing rates are strongly influenced by the presence of a mean flow nearly everywhere as shown by comparison with an eddy only calculation with the mean flow absent finally results are compared with other recent estimates of mixing rates using lagrangian and inverse methods

incorporation of polarimetric radar images into multisensor data sets a technique is presented for registering polarimetric synthetic aperture radar sar data to other aircraft and spaceborne data sets resampling is done on the full stokes matrix allowing full polarization synthesis on the coregistered data set analysis of data acquired over pisgah crater in the mojave desert ca as part of the mojave field experiment shows that the resampling does not seriously affect the pedestal heights of polarization signatures or estimates of rms heights for smooth to moderately rough surfaces

mineralogic information from a new airborne thermal infrared multispectral scanner a new six channel aircraft multispectral scanner has been developed to exploit mineral signature information at wavelengths between 8 and 12 micrometers preliminary results show that igneous rock units can be identified from their free silica content and that carbonate as well as clay bearing units are readily separable on the digitally processed images

multisensor classification of sedimentary rocks abstract this paper compares linear discriminant analysis and supervised classification results based on signatures from the landsat thematic mapper tm the thermal infrared multispectral scanner tims and airborne synthetic aperture radar sar alone and combined into extended spectral signatures for seven sedimentary rock units exposed on the margin of the wind river basin wyoming results from a linear discriminant analysis showed that training area classification accuracies based on the multisensor data were improved an average of 15 over tm alone 24 over tims alone and 46 over sar alone with similar improvement resulting when supervised multisensor classification maps were compared to supervised individual sensor classification maps when training area signatures were used to map spectrally similar materials in an adjacent area the average classification accuracy improved 19 using the multisensor data over tm alone 2 over tims alone and 11 over sar alone the conclusion of this study is that certain sedimentary lithologies may be accurately mapped using a single sensor but classification of a variety of rock types can be improved using multisensor data sets that are sensitive to different characteristics such as mineralogy and surface roughness

float derived isopycnal diffusivities in the dimes experiment as part of the diapycnal and isopycnal mixing experiment in the southern ocean dimes 210 subsurface floats were deployed west of the drake passage on two targeted density surfaces absolute single particle diffusivities are calculated for the floats the focus is on the meridional component which is less affectedby the meanshear the diffusivitiesare estimatedin severalways including a novelmethodbased on the probability density function of the meridional displacements this allows the determination of the range of possible lateral diffusivities as well as the period over which the spreading can be said to be diffusive the method is applied to the float data and to synthetic trajectories generated with the massachusetts institute of technologygeneral circulationmodel mitgcm becauseof ballastingproblems manyofthefloatsdid not remain on their targeted density surface however the float temperature records suggest that most occupied asmallrangeofdensities sothefloatsweregroupedtogetherfortheanalysis thelatterfocuseson asubsetof 109 of the floats launched near 1058w the different methods yield a consistent estimate for the diffusivity of 800 6 200m 2 s 21 the same calculations were made with model particles deployed on 20 different density surfaces and the result for the particles deployed on the neutral density surface g 5 27 7 surface was the same within the errors the model was then used to map the variation of the diffusivity in the vertical near the core of the antarctic circumpolar current acc the results suggest mixing is intensified at middepths between 1500 and 2000m consistent with several previous studies

analysis of coregistered landsat seasat and sir a images of varied terrain types multisensor image data sir a seasat sar and landsat mss over areas in nothern algeria and eastern utah have been coregistered in order to assess the complementary effects of the orbital sensors for geologic mapping in two very different terrains this first attempt at registering such a data set shows that the radar backscatter information provided by the sir a image increases the classification accuracy of several geologic units over the landsat image alone and over combined landsat and seasat images

isopycnal lagrangian statistics from the north atlantic current rafos float observations one hundred isopycnal floats were tracked on the 27 2 and 27 5 surfaces in the newfoundland basin nfb from july 1993 to july 1995 to study the current structure and exchanges of waters between the subtropical and subpolar gyres the float mapped mean flow consists of weak flows in the nfb and a strong boundary current the north atlantic current nac which separates from the boundary at the northwest corner becoming a diffusive zonal drift the nac meanders are linked to topography and have similar patterns on the two isopycnals despite the fact that the upper layer velocities are twice as fast as the lower layer ones perturbation velocity from the mean is used to compute isopycnal turbulent dispersion and diffusivity this large data set allows us to resolve a narrow mean nac and results in a gaussian turbulence the turbulence approximately follows the classic taylor dispersion theory integral timescales and length scales and turbulent isopycnal diffusivity are of 1 5 2 5 days 20 30 km and 1 7 103 m2 s 1 respectively the timescale increases with depth and decreases with latitude the length scale decreases with depth and longitude and the diffusivity decreases with depth and from nac to nfb compared to previous results from surface drifters and isobaric floats our isopycnal statistics are more isotropic and agree better with the taylor dispersion theory because 1 the mean velocity has a better resolution and 2 the isopycnal floats are better lagrangian followers the diffusivity scales better with the rms velocity and length scale than with the velocity variance and timescale

four views of a portion of the north atlantic subtropical gyre abstract data from four cruises to the triangle centered at 27 n 32 30 w were smoothed by fitting second degree polynomials at each of about 30 different density surfaces the density intervals were p 0 3 corresponding to about 50 db intervals in pressure from the polynomials determination was made of central values horizontal derivatives and laplacians of the fields of pressure salt oxygen and dynamic height in addition maps of the fits and deviations of each nation from the smoothed fits were produced from the steady advective diffusive equation and the smoothed fits to the age oxygen and dynamic height fields the lateral isopycnal diffusivity as estimated to be kh 0 5 103 m2 s 1 although the salt field was reasonably stable from cruise to cruise the variability of the baroclinic velocity shear was found to be as large as the baroclinic shear itself the maps suggest a wobble of the gyre the standard deviation of the fluctuations at each nation from the smoothed fits when norma

climate influenced cave deposition and human occupation during the pleistocene in zhiren cave southwest china abstract a large number of hominin fossil bearing caves in south china have yielded evidence for the occupation of early modern humans during the middle to late pleistocene however the geology of these caves and the paleoenvironmental context of human occupation remain poorly documented and understood in this study we obtained new ages yielded by mc icpms uranium series dating of speleothems from zhiren cave guangxi where a partial early modern human mandible and 2 m have been recovered the ages demonstrate that cave infilling of zhiren cave began at 1 ma much earlier than the date previously suggested our dating results also suggest that fossils of anatomically modern human were deposited in zhiren cave during marine isotope stage mis 6 between 190 and 130 ka representing the oldest known anatomically modern human remains in east asia the cave s sedimentary processes and the paleoenvironmental changes were reconstructed based on detailed analyses of lithostratigraphy grain size pollen assemblages and the chemical weathering intensity of the sediments inside zhiren cave the results show that major climatic changes in the middle pleistocene led to the accelerated incision of local streams and the erosion of cave sediments by controlling the regional hydrological response during the early to middle pleistocene after 300 ka increased climatic contrasts between glacial and interglacial periods dominated the accumulation of sediments and the occupation of mammals and early modern humans in zhiren cave gradually desiccating climatic conditions and reduced forest cover during the penultimate glacial period mis 6 may have define a temporal window for the human occupation of zhiren cave providing ideal environmental conditions however floodwater incursion and or dense vegetation cover corresponding to a much warmer and wetter climate in the subsequent last interglacial mis 5 may have discouraged humans from further occupying zhiren cave

lateral diffusivity and lagrangian scales in the pacific ocean as derived from drifter data 1 the global drifter program surface velocity program data set is used to derive maps of the lateral diffusivity and lagrangian scales of velocity length and time across the whole pacific for the lateral diffusivity the minor principal component of both the davis diffusivity tensor and the half growth rate of the single particle dispersion tensor were calculated in 5 5 bins from drifters for the period 1979 1999 estimates of the lateral diffusivity k obtained by means of the minor principal component approach are shown to correspond well with other authors estimates for the pacific the highest values of k 2 3 104 m2 s are found in the eastern equatorial pacific while the lowest ones 2 3 103 m2 s are typical for forty odd degrees in latitude northward of the subpolar fronts in both hemispheres and for the subtropics in the eastern part of the south pacific high values of k about 1 104 m2 s are also observed in the kusoshio kuroshio extension area and in the equatorial pacific along the whole length of the equator there are two approximately symmetrical tongues of high k value in the western pacific centered around 21 n and 24 s respectively in general k has a tendency to increase westward eastward in the midlatitudes equatorial region and toward the equator in both hemispheres in the midlatitudes the lagrangian length scale l is found to be approximately equal to the first mode baroclinic radius of deformation ri while the rossby number defined as ro tearth t sin where t is the lagrangian timescale tearth is the period of the earth s rotation and is the latitude is less than unity implying that the quasigeostrophic mesoscale eddies are the main mechanism for lateral mixing the lateral diffusivity in the midlatitudes is suggested to be parameterized as k v2ri where v2 is the lagrangian velocity scale inherent to a mesoscale eddy field in the low latitudes l becomes less than ri and the condition ro 1 is no longer valid which implies the change of the eddy controlled mechanism of lateral mixing by another mechanism

3h and 3he in the beta triangle observations of gyre ventilation and oxygen utilization rates abstract isopycnal maps of 3h 3he age with about 100 km resolution have been obtained for a 1000 km scale area in the eastern subtropical north atlantic the midscale texture of the maps is consistent with isopycnal diffusivities of order 500 m 2 s 1 analysis of the distributions within the context of advection diffusion equations reveals that the larger scale 3h 3he age gradients observed within the area are not seriously affected by mixing on those surfaces that outcrop in the region of ekman downwelling thus isopycnal velocities can be estimated from 1 but record only the velocity component normal to the outcrop the velocities thus obtained agree well with geostrophic estimates although the comparison is flawed by the fundamental mismatch in timescales between the two techniques backward extrapolation of the maps to zero age outcrop positions indicate that the contribution of unventilated older recirculated water to the gyre flow above 600 m depth is small in this area no more than 20

direct estimate of lateral eddy diffusivity upstream of drake passage abstractthe first direct estimate of the rate at which geostrophic turbulence mixes tracers across the antarctic circumpolar current is presented the estimate is computed from the spreading of a tracer released upstream of drake passage as part of the diapycnal and isopycnal mixing experiment in the southern ocean dimes the meridional eddy diffusivity a measure of the rate at which the area of the tracer spreads along an isopycnal across the antarctic circumpolar current is 710 260 m2 s 1 at 1500 m depth the estimate is based on an extrapolation of the tracer based diffusivity using output from numerical tracers released in a one twentieth of a degree model simulation of the circulation and turbulence in the drake passage region the model is shown to reproduce the observed spreading rate of the dimes tracer and suggests that the meridional eddy diffusivity is weak in the upper kilometer of the water column with values below 500 m2 s 1 and peaks at the steering level near 2 km where the eddy ph

propagation of sound through a spicy ocean the sofar overture using a closely sampled 1000 km hydrographic section in the eastern north pacific the sound speed finestructure is separated into two component fields i isopyncal tilt dominated by internal waves the traditional view and ii spicy cold fresh to hot salty millifronts associated with upper ocean stirring numerical transmission experiments show significant scatter within the mixed layer from the spicy fronts this scattered energy arrives near the start of the sofar sequence and is superimposed on a triplication of the channel dispersion at the transition from reflected to upper ocean refracted energy this sofar overture is totally different from the finale which has been prominent for over 50 years the critical dependence of the overture on mixed layer processes suggests a scheme for acoustically monitoring the upper oceans at surface conjugate depths 3 to 5 km offering some advantages over in situ monitoring

new 400 320 ka gigantopithecus blacki remains from hejiang cave chongzuo city guangxi south china abstract gigantopithecus blacki is a typical member of the stegodon ailuropoda faunal complex sensu lato that inhabited southern china or more broadly mainland southeast asia during the early and middle pleistocene current evidence indicates that the giant ape became extinct during the middle pleistocene recently new remains of g blacki and associated mammalian fossils have been unearthed from a karst cave site hejiang cave in chongzuo city guangxi south china the age of the gigantopithecus bearing depositional unit is estimated to be 400 320 ka using 230th 234u disequilibrium u series dating of flowstone samples bracketing the deposits these finds document the latest occurrence of gigantopithecus and provide potential insights regarding its extinction comparisons of dental dimensions between the hejiang g blacki remains more than four hundred isolated teeth from early pleistocene localities and over ninety isolated teeth from local drugstores show that the hejiang teeth are slightly larger in their buccolingual dimensions in addition the crowns of the three unerupted upper premolars differ from those of all of the other gigantopithecus material in having more complex crenulations the differences in dental dimensions and morphology are possibly reflective of dietary responses to environmental changes that eventually led to the extinction of gigantopithecus

on the width of the equatorial deep jets the equatorial deep jets edj are a striking feature of the equatorial ocean circulation in the atlantic ocean the edj are associated with a vertical scale of between 300 and 700 m a time scale of roughly 4 5 years and upward energy propagation to the surface it has been found that the meridional width of the edj is roughly 1 5 times larger than expected based on their vertical scale here we use a shallow water model for a high order baroclinic vertical normal mode to argue that mixing of momentum along isopycnals can explain the enhanced width a lateral eddy viscosity of 300 m2 s 1 10 is found to be sufficient to account for the width implied by observations

the spatial distribution and annual cycle of upper ocean thermohaline structure 1 observations of the spatial distribution and persistence of thermohaline structure are presented and show how advection and diffusion affect a passive tracer more than two years of underwater glider observations in the central subtropical north pacific showed thermohaline variability over horizontal scales from 5 to 1300 km thermohaline fluctuations along isopycnals spice fluctuations were elevated in layers throughout the water column with the largest fluctuations near the surface and subtropical frontal regions fluctuations were uncorrelated between the layers but stirred by the same velocity field spice variance had local extrema in the vertical because of differences in source water properties and the influence of neighboring water masses spice variance spanned about three orders of magnitude along deeper isopycnals with larger variance where different water masses met and where velocity and vorticity variance were elevated horizontal wave number spectra of spice had slopes of 2 everywhere in the upper 1000 m submesoscale spice fluctuations had slopes in physical space near the ratio of the coriolis parameter to the buoyancy frequency f n consistent with predictions of quasi geostrophic theory in the mixed layer thermohaline structure had a significant annual cycle with smaller interannual differences thermohaline fluctuations left behind during restratification and isolated from the mixed layer decayed with time because of diffusion along isopycnals horizontal diffusivity estimates in the remnant mixed layer were 0 4 m2 s 1 at 15 28 km wavelengths and 0 9 m2 s 1 at 35 45 km wavelengths

geologic interpretation of space shuttle radar images of indonesia the national aeronautics and space administration nasa space shuttle mission in november 1981 acquired images of parts of the earth with a synthetic aperture radar system at a wavelength of 23 5 cm 9 3 in and spatial resolution of 38 m 125 ft this report describes the geologic interpretation of 1 250 000 scale images of irian jaya and eastern kalimantan indonesia where the all weather capability of radar penetrates the persistent cloud cover the inclined look direction of radar enhances subtle topographic features that may be the expression of geologic structures on the indonesian images the following terrain categories are recognizable for geologic mapping carbonate clastic volcanic alluvial and coastal melange and metamorphic as well as undifferentia ed bedrock regional and local geologic structures are well expressed on the images in the vogelkop region of irian jaya the major tectonic elements tamrau mountains sorong fault kemum block bintuni basin and lengguru foldbelt are readily mapped on the image of the sorong fault geomorphic features offset drainage shutterridges aligned notches provide clear evidence for left lateral strike slip displacement several lineaments on the image correlate with previously mapped faults other lineaments may be the expression of previously unrecognized faults on the image of the mainland of irian jaya a belt of metamorphic and melange terrain marks the zone of collision between the pacific plate and the australian plate the high central range of irian jaya is located south of the metamorphic and melange belt the generally homoclinal structure of the central range is interrupted in the paniai lake region by a series of southward directed thrust plates indicated by belts of carbonate terrain new guinea limestone group that alternate with belts of clastic terrain kembelangan formation in the image of eastern kalimantan several major foldbelts are clearly expressed these limited examples of space shuttle radar images demonstrate their value for geologic interpretation of indonesia it is recommended that future shuttle missions acquire complete radar coverage of the main islands of indonesia for use in geologic mapping and energy exploration shuttle radar images would also be valuable for other cloud covered forested regions

isopycnal diffusivities in the antarctic circumpolar current inferred from lagrangian floats in an eddying model average 750 250 m 2 s 1 around the polar frontal zone the results imply that parameterizations that only use eddy kinetic energy to parameterize the diffusivities are incomplete we suggest that dominant correlations of lagrangian eddy diffusivities with eddy kinetic energy found in previous studies may have been due to the use of too short time lags in the integration of the velocity autocovariance used to infer the diffusivities we find evidence that strong mean flow inhibits cross stream mixing within the acc but there are also areas where cross stream diffusivities are large in spite of strong mean flows for example in regions close to topographic obstacles such as the kerguelen plateau

mixing of a tracer in the pycnocline a patch of sulfur hexafluoride was released in may 1992 in the eastern north atlantic on an isopycnal surface near 300 m depth and was surveyed over a period of 30 months as it dispersed across and along isopycnal surfaces the diapycnal eddy diffusivity k estimated for the first 6 months was 0 12 0 02 cm2 s while for the subsequent 24 months it was 0 17 0 02 cm2 s the vertical tracer distribution remained very close to gaussian for the full 30 months as the root mean square rms dispersion grew from 5 to 50 m lateral dispersion was measured on several scales the growth of the rms width of the tracer streaks from less than 100 m to approximately 300 m within 2 weeks implies an isopycnal diffusivity of 0 07 m2 s at scales of 0 1 to 1 km larger than expected from the interaction between vertical shear of the internal waves and diapycnal mixing teasing of the overall patch initially about 25 km across into streaks with an overall length of 1800 km within 6 months supports predictions of exponential growth by the mesoscale strain field at a rate of 3 0 5 10 7 s 1 the rms width of these streaks estimated as 3 km and maintained in the face of the streak growth indicates an isopycnal diffusivity of 2 m2 s at scales of 1 to 10 km much greater than expected from internal wave shear dispersion the patch was painted in albeit streakily by 12 months confirming expectations from analytical and numerical models homogenization of the patch continued during the subsequent 18 months while the patch continued to spread with an effective isopycnal eddy diffusivity on the order of 1000 m2 s acting at scales of 30 to 300 km

the history and decay of a mediterranean salt lens subsurface coherent vortices called meddies1 are formed by the outflow of salty water from the mediterranean sea1 2 into the north atlantic in october 1984 we began a study to observe the life history and large scale changes of a meddy by identifying a specific meddy and carefully mapping it and seeding it with sofar floats3 these neutrally buoyant floats are tracked acoustically and can be located aboard ship as this meddy moved southward across the madeira abyssal plain it was resurveyed three more times during a span of two years being able to find this same lens 100km in diameter on successive surveys was itself a unique achievement that allowed us to observe the meddy evolution and to gain new insight into the importance of different mixing mechanisms that cause meddy decay we find evidence of mixing by at least three processes 1 lateral mixing by the exchange of layers of water thermohaline intrusions 4 5 2 vertical mixing at the underside of the lens by salt fingers6 and 3 mixing by turbulence together these cause the net heat and salt anomalies to decay with an e folding time of about one year despite the mixing the relative vorticity at the core remained constant for the first year and the meddy retained its coherent shape over a two year period

eddy stirring and horizontal diffusivity from argo float observations geographic and depth variability stirring along isopycnals is a significant factor in determining the distribution of tracers within the ocean salinity anomalies on density surfaces from argo float profiles are used to investigate horizontal stirring and estimate eddy mixing lengths eddy mixing length and velocity fluctuations from the ecco2 global state estimate are used to estimate horizontal diffusivity at a 300 km scale in the upper 2000 m with near global coverage diffusivity varies by over two orders of magnitude with latitude longitude and depth in all basins diffusivity is elevated in zonal bands corresponding to strong current regions including western boundary current extension regions the antarctic circumpolar current and equatorial current systems the estimated mixing lengths and diffusivities provide an observationally based data set that can be used to test and constrain predictions and parameterizations of eddy stirring

estimates of surface roughness derived from synthetic aperture radar sar data radar remote sensing data provide a unique perspective on the earth s crust and the processes that have influenced its evolution physically based models are required however to relate the geophysical quantities being measured by the radar sensor to useful geologic information synthetic aperture radar sar data over the cima volcanic field in the mojave desert of california are quantitatively connected with microtopography through inversion of a radar backscatter model changes in surface roughness inferred from the derived microtopography are modeled and found to be consistent with aeolian mantling as surfaces age estimated rates of aeolian deposition for the cima area are compared to the lunar crater volcanic field in nevada rates of deposition appear to be higher at cima volcanic field most likely because of its proximity to soda lake the main source of the aeolian material

stirring in the global surface ocean 1 global variations of stirring in the surface ocean are quantified using finite time lyapunov exponents ftles calculated from currents derived from satellite altimetry it is shown that the stirring is highly non uniform and the probability distribution functions pdfs of the ftles are broad asymmetric and have long high stretch tails the characteristics of the pdfs vary with mesoscale activity and integration time there are larger values and broader pdfs in regions of high strain rates and eddy kinetic energy eke e g western boundary currents and the antarctic circumpolar current and for shorter integration times the pdfs have a near universal relationship with the mean strain of a region and are reasonably well fit by weibull distributions the above variations in the stirring may help our understanding of the distribution and spatial heterogeneities of biogeochemical tracers and raise the possibility of developing a parameterization of the stirring based on the easily calculated eke

robust and nonrobust aspects of atlantic meridional overturning circulation variability and mechanisms in the community earth system model abstractrobust and nonrobust aspects of atlantic meridional overturning circulation amoc variability and mechanisms are analyzed in several 600 yr simulations with the community earth system mode

thorough assessment of dna preservation from fossil bone and sediments excavated from a late pleistocene holocene cave deposit on kangaroo island south australia fossils and sediments preserved in caves are an excellent source of information for investigating impacts of past environmental changes on biodiversity until recently studies have relied on morphology based palaeontological approaches but recent advances in molecular analytical methods offer excellent potential for extracting a greater array of biological information from these sites this study presents a thorough assessment of dna preservation from late pleistocene holocene vertebrate fossils and sediments from kelly hill cave kangaroo island south australia using a combination of extraction techniques and sequencing technologies ancient dna was characterised from over 70 bones and 20 sediment samples from 15 stratigraphic layers ranging in age from 20 ka to 6 8 ka a combination of primers targeting marsupial and placental mammals reptiles and two universal plant primers were used to reveal genetic biodiversity for comparison with the mainland and with the morphological fossil record for kelly hill cave we demonstrate that kelly hill cave has excellent long term dna preservation back to at least 20 ka this contrasts with the majority of australian cave sites thus far explored for ancient dna preservation and highlights the great promise kangaroo island caves hold for yielding the hitherto elusive dna of extinct australian pleistocene species

early pleistocene glacial cycles and the integrated summer insolation forcing long term variations in northern hemisphere summer insolation are generally thought to control glaciation but the intensity of summer insolation is primarily controlled by 20 000 year cycles in the precession of the equinoxes whereas early pleistocene glacial cycles occur at 40 000 year intervals matching the period of changes in earth s obliquity the resolution of this 40 000 year problem is that glaciers are sensitive to insolation integrated over the duration of the summer the integrated summer insolation is primarily controlled by obliquity and not precession because by kepler s second law the duration of the summer is inversely proportional to earth s distance from the sun

integrated analysis of high resolution field and airborne spectroradiometer data for alteration mapping oatman epithermal gold deposit in northwest arizona pervasive argillic and wall rock phyllic and propylitic alteration discrimination of these zones rests on identification of the dominant alteration minerals alunite illite mica and chlorite modified journal abstract

global observations of horizontal mixing from argo float and surface drifter trajectories mixing by mesoscale eddies in the ocean plays a major role in setting the distribution of oceanic tracers with important implications for physical and biochemical systems at local to global scales roach et al 2016 https doi org 10 1002 2015jc011440 demonstrated that a two particle analysis of argo trajectories produces robust estimates of horizontal mixing in the southern ocean here we extend this analysis to produce global 1 1 maps of eddy diffusivity at the nominal argo parking depth of 1 000 m we also applied this methodology to estimate surface eddy diffusivities from global drifter program gdp surface drifters the global mean eddy diffusivity was 543 155 m2 s at 1 000 m and 2637 311 m2 s at the surface with elevated diffusivities in regions of enhanced eddy kinetic energy such as western boundary currents and along the antarctic circumpolar current the eddy kinetic energy at the equator is high at both the surface and depth but the eddy diffusivity is only enhanced near the surface at depth the eddy diffusivity is strongly suppressed due to the presence of mean flow we used our observational estimates to test the validity of an eddy diffusivity parameterization that accounts for mixing suppression in the presence of zonal mean flows our results indicated that this parameterization generally agrees with the directly observed eddy diffusivities in the midlatitude and high latitude oceans