the shape and internal structure of the moon from the clementine mission global topographic and gravitational field models derived from data collected by the clementine spacecraft reveal a new picture of the shape and internal structure of the moon the moon exhibits a 16 kilometer range of elevation with the greatest topographic excursions occurring on the far side lunar highlands are in a state of near isostatic compensation whereas impact basins display a wide range of compensation states that do not correlate simply with basin size or age a global crustal thickness map reveals crustal thinning under all resolvable lunar basins the results indicate that the structure and thermal history of the moon are more complex than was previously believed

wind driven circulation for the eastern north atlantic subtropical gyre from argo data 1 a trans oceanic section at 24 5 n in the north atlantic has been sampled at a decadal frequency this work demonstrates that the wind driven component of the meridional overturning circulation moc may be monitored using autonomous profiling floats deployed in the eastern north atlantic subtropical gyre more than 500 ctd vertical profiles from the surface to 2000 m depth spanning one year from april 2002 to march 2003 are used to compute the geostrophic transport stream function at 24 5 n the baroclinic transport obtained from the autonomous profiling floats is not statistically different than that from three hydrographic cruises carried out in 1957 1981 and 1992 a good agreement is found between the geostrophic transport stream function and the transport derived from the wind field through the sverdrup relation

on the seasonal variability of the canary current and the atlantic meridional overturning circulation the atlantic meridional overturning circulation amoc is continually monitored along 26 n by the rapid mocha array measurements from this array show a 6 7 sv seasonal cycle for the amoc with a 5 9 sv contribution from the upper mid ocean recent studies argue that the dynamics of the eastern atlantic is the main driver for this seasonal cycle specifically rossby waves excited south of the canary islands using inverse modelling hydrographic mooring and altimetry data we describe the seasonal cycle of the ocean mass transport around the canary islands and at the eastern boundary under the influence of the african slope where eastern component of the rapid mocha array is situated we find a seasonal cycle of 4 1 0 5 sv for the oceanic region of the canary current and 3 7 0 4 sv at the eastern boundary this seasonal cycle along the eastern boundary is in agreement with the seasonal cycle of the amoc that requires the lowest contribution to the transport in the upper mid ocean to occur in fall however we demonstrate that the linear rossby wave model used previously to explain the seasonal cycle of the amoc is not robust since it is extremely sensitive to the choice of the zonal range of the wind stress curl and produces the same results with a rossby wave speed of zero we demonstrate that the seasonal cycle of the eastern boundary is due to the recirculation of the canary current and to the seasonal cycle of the poleward flow that characterizes the eastern boundaries of the oceans

some observations of the azores current and the north equatorial current the regions containing the two zonal currents of the subtropical gyre in the eastern north atlantic the azores current and the north equatorial current nec have quite different physical characteristics associated with the azores current are strong horizontal thermohaline gradients that can be located easily both at the surface and at depth with temperature data alone thus making satellite ir imagery and expendable bathythermograph profiles suitable for observing it during winter the surface expression of the azores current is often found to the north of the strongest subsurface gradients in contrast to the azores current and to the central water mass boundary just to the south the nec has relatively weak horizontal temperature and salinity gradients requiring density information in order to identify it there is no clear surface manifestation found with the nec common to both currents though is that each transports o 8 sv in the upper 800 m of the ocean near 27 w with the largest velocities being in the upper 400 m

composition of orientale basin deposits and implications for the lunar basin forming process the orientale basin on the lunar western limb has served as the prototype lunar multiring basin for many years in order to constrain possible models of the formation and excavation of basin ejecta we have studied the composition of orientale basin deposits using both earth based spectral reflectance and apollo orbital geochemical data results indicate that orientale basin ejecta are dominantly anorthositic with compositions ranging from pure anorthosite to noritic anorthosite although minor quantities of mare basalt and low k fra mauro basalt are present ultramafic and kreep components appear to be absent portions of the inner rings of the basin may be composed of anorthosite whose shock levels exceed 20 gpa 200 kbar in conjunction with photogeologic evidence for the preservation of prebasin topography and structure within the cordillera basin ring we suggest that the diameter of the excavation crater of the orientale basin is on the order of 500 to 600 km effective depths of excavation are probably less than about half the local crustal thickness which in this region is on the order of 100 km we find that the orientale impact excavated dominantly upper crustal rocks with a depth of excavation consistent with a proportional growth basin forming model

bulk composition of regolith fines on lunar crater floors initial investigation by lro mini rf abstract identifying polarimetric radar signatures of ice in smooth regolith fines on the floors of permanently shadowed lunar craters is hindered by uncertainties in their dielectric properties we address this deficiency through polarimetric radar analysis of surface backscatter to derive the dielectric constant e r of smooth rock free regolith fines covering brecciated crater floors observed by mini rf which offer ideal locations for unambiguous retrieval of surface e r from linear polarimetric scattering models and cpr analysis for volatile identification specifically we select fines covering crater fills in north polar and equatorial regions to constrain the range of variability of e r as a function of latitude and crater diameter where we hypothesize that the latter is indicative of the excavation depth of these fines our observations suggest that there is measurable variability in the dielectric properties of fines on lunar crater floors as a function of crater size and potentially with impact excavation depth suggesting that small craters e r ranging from 2 3 to 3 and large ones 5 km have higher values of e r that range from 3 to 3 8 we find that the most plausible explanation for the observed variability of e r of regolith fines on crater floors is mineralogical differences suggesting an increase in metal abundance in the original excavated substrate with depth i e in the uppermost kilometer of the lunar crust finally we suggest that regolith fines on the floors of permanently shadowed craters

mass fluxes in the canary basin abstract ocean studies in the 1970s provided an improved knowledge of the coastal upwelling region off nw africa while in the 1980s and 1990s they led to a good description of the open ocean flow patterns in the canary basin it was not until the late 1990s that major research addressed the open coastal ocean coupled response here we examine the mean and seasonal circulation patterns in the canary basin with data from four hydrographic cruises carried out in the region between cape ghir madeira island and the canary islands we apply an inverse box model to an ocean divided into 14 layers with several layers representing each water mass or stratum to obtain mass fluxes consistent with the thermal wind equation an optimum flow description is obtained using conservation of mass salt and heat anomaly biologically corrected oxygen and silicate and allowing for ekman transport in the surface layer and dianeutral mixing between adjacent layers the deep waters show no predominant flow direction while the intermediate waters display localized southward flowing mediterranean water far from shore and northward flowing antarctic intermediate water near the continental slope specially in the passage between the eastern canary islands and the african slope the mean upper thermocline canary current composed of north atlantic central water flows south with an open ocean branch transporting about 3 1 sv 1 sv 10 6 m 3 s 1 10 9 kg s 1 and an upwelling related branch near the continental slope carrying 1 0 3 sv the seasonal transport by the open ocean branch intensifies and moves offshore from spring to fall 2 8 1 2 sv in spring 2 9 1 1 sv in summer and 4 5 1 2 sv in fall while it carries its lowest southward mass flux in winter 1 7 1 0 sv possibly as a result of a migration offshore the sampled region upwelling related southward flow is present in spring and summer 1 9 0 1 sv and 2 4 0 1 sv respectively while in fall and winter it merges with the offshore southward branch this westward migration allows a northward mass flux between the canary islands and the african coast 1 8 0 1 sv that by winter reaches cape ghir 0 5 0 2 sv seasonal air sea heat fluxes fit well with the climatological values the net phosphate transport in the surface layer indicates that primary production was negligible in this region during january 1997 and april 1998 though in this last month production was probably starting as a result of significant nutrient supply

analysis of lunar samples implications for planet formation and evolution the analysis of lunar samples returned to earth by the apollo and luna missions changed our view of the processes involved in planet formation the data obtained on lunar samples brought to light the importance during planet growth of highly energetic collisions that lead to global scale melting this violent birth determines the initial structure and long term evolution of planets once past its formative era the lunar surface has served as a recorder of more than 4 billion years of interaction with the space environment the chronologic record of lunar cratering determined from the returned samples underpins age estimates for planetary surfaces throughout the inner solar system and provides evidence of the dynamic nature of the solar system during the planet forming era

characterization of previously unidentified lunar pyroclastic deposits using lunar reconnaissance orbiter camera data 1 we used a lunar reconnaissance orbiter camera lroc global monochrome wide angle camera wac mosaic to conduct a survey of the moon to search for previously unidentified pyroclastic deposits promising locations were examined in detail using lroc multispectral wac mosaics high resolution lroc narrow angle camera nac images and clementine multispectral ultraviolet visible or uvvis data out of 47 potential deposits chosen for closer examination 12 were selected as probable newly identified pyroclastic deposits potential pyroclastic deposits were generally found in settings similar to previously identified deposits including areas within or near mare deposits adjacent to highlands within floor fractured craters and along fissures in mare deposits however a significant new finding is the discovery of localized pyroclastic deposits within floor fractured craters anderson e and f on the lunar farside isolated from other known similar deposits our search confirms that most major regional and localized low albedo pyroclastic deposits have been identified on the moon down to 100 m pix resolution and that additional newly identified deposits are likely to be either isolated small deposits or additional portions of discontinuous patchy deposits

scaling impact melting and crater dimensions implications for the lunar cratering record abstract the dimensions of large craters formed by impact are controlled to a large extent by gravity whereas the volume of impact melt created during the same event is essentially independent of gravity this differential scaling fosters size dependent changes in the dynamics of impact crater and basin formation as well as in the final morphologies of the resulting structures a variety of such effects can be observed in the lunar cratering record and some predictions can be made on the basis of calculations of impact melting and crater dimensions among them are the following 1 as event magnitude increases the volume of melt created relative to that of the crater will grow and more will be retained inside the rim of the crater or basin 2 the depth of melting will exceed the depth of excavation at diameters that essentially coincide with both the inflection in the depth diameter trend and the simple to complex transition 3 the volume of melt will exceed that of the transient cavity at a cavity diameter on the order of the diameter of the moon this would arguably correspond to a moon melting event 4 small lunar craters only rarely display exterior flows of impact melt because the relatively small volumes of melt created can become choked with clasts increasing the melt s viscosity and chilling it rapidly larger craters and basins should suffer little from such a process 5 deep melting near the projectile s axis of penetration during larger events will yield a progression in cen tral structure morphology with growing event magnitude this sequence should range from single peaks through multiple peaks to peak rings 6 the minimum depth of origin of central peak material should co incide with the maximum depth of melting the main central peak in a crater the size of tycho should have had a preimpact depth of close to 15 km

a comparison of volcanic eruption processes on earth moon mars io and venus the silicate planets and satellites display a wide range of physical chemical and atmospheric characteristics which may influence the nature of volcanism a major geological process common to the evolution of the surfaces of these bodies consideration of the process of magma ascent and eruption from first principles allows predictions to be made concerning volcanic eruption styles and expected landforms and deposits on each planetary body examination of actual land forms and deposits in light of these predictions leads to a better understanding of the nature of volcanic eruption processes and outlines outstanding problems

instability dynamics of a subtropical jet and applications to the azores front current system eddy driven mean flow abstract the azores front is associated with an eastward flowing subtropical jet which coincides with the northern edge of the north atlantic subtropical gyre and forms a southern branch of the gulf stream an intensive study of the eddy driven mean flow induced by the nonlinear instability of the jet has been conducted using a primitive equation numerical model initialized with the summer hydrological fields typical of the azores front the authors show that the mesoscale patterns that appear after a few months are largely determined by baroclinic instability processes the jet and its associated mesoscale turbulence have a strong meridional asymmetry due to the strongly sloping thermocline in general an anticyclonic meander which grows and deforms northwestward generates a pinched off anticyclone while a cyclonic meander which grows and deforms southwestward degenerates in a thin filamental structure that will dissipate before any cyclone can be pinched off the authors propose a mechanism that

using argo data to investigate the meridional overturning circulation in the north atlantic abstract using a variety of oceanographic data including direct volume transports in the florida strait and argo float profiles and drift velocities at 24 n and 36 n in the north atlantic inverse calculations are presented in which the net meridional transport down to a depth of approximately 1600 m is estimated at both latitudes for a 5 year period 2003 2007 the upper ocean is divided into seven layers using neutral density and mass conservation constraints have been applied to a closed box bounded by these latitudes including the florida strait ekman layer transports have been included in the top most layer and the inverse calculation has solved for changes from the initial reference velocities ekman and florida strait transports given a priori estimates on the accuracy of each of these quantities solutions with and without transformations due to mediterranean water mw formation are made our results indicate that 1 time averaged transport estimates derived from argo have significant less eddy noise than individual hydrographic sections 2 argo drift velocities provide information to the inverse solution for the ocean interior and 3 comparison of the total integrated interior mass transports in the thermocline waters for the period 2003 2007 with the previous estimates based on trans ocean hydrographic sections shows that within the errors of our estimation the upper limb of the atlantic meridional overturning circulation has not significantly changed since 1957

circulation and nutrients in middepth atlantic waters isopycnal analyses of distributions of salinity oxygen apparent oxygen utilization nitrate and silica in the depth range 800 3000 m in the north and tropical atlantic ocean are carried out using data from the transient tracers in the oceans meteor cruise 56 leg 5 atlantis ii cruise 109 legs 1 and 3 and the geosecs atlantic study the results are summarized in isopycnal distribution maps and property property plots the layer between 800 and 1500 m is oxygen poor and nutrient rich and is poorly ventilated below this is a better aerated layer with the deep western boundary current part of which separates along the equator regeneration of nutrients and consumption of oxygen persist into the deep ocean in regions off the west coast of africa the mediterranean outflow water apparently is causing significant cross isopycnal mixing through salt fingering the resultant cross isopycnal velocity may be large enough to cause significant vorticity stretching

the constitution and structure of the lunar interior the current state of understanding of the lunar interior is the sum of nearly four decades of work and a range of exploration programs spanning that same time period missions of the 1960s including the rangers surveyors and lunar orbiters as well as earth based telescopic studies laid the groundwork for the apollo program and provided a basic understanding of the surface its stratigraphy and chronology through a combination of remote sensing surface exploration and sample return the apollo missions provided a general picture of the lunar interior and spawned the concept of the lunar magma ocean in particular the discovery of anorthite clasts in the returned samples led to the view that a large portion of the moon was initially molten and that crystallization of this magma ocean gave rise to mafic cumulates that make up the mantle and plagioclase flotation cumulates that make up the crust smith et al 1970 wood et al 1970 this model is now generally accepted and is the framework that unifies our knowledge of the structure and composition of the moon the intention of this chapter is to review the major advances that have been made over the past decade regarding the constitution of the moon s interior much of this new knowledge is a direct result of data acquired from the successful clementine and lunar prospector missions as well as the analysis of new lunar meteorites as will be seen results from these studies have led to many fundamental amendments to the magma ocean model much of what we know from sample analyses has been previously summarized elsewhere and only their most important aspects will be discussed in this chapter the reader is referred to the relevant chapters in the books basaltic volcanism on the terrestrial planets basaltic volcanism study project 1981 the

canary current and north equatorial current from an inverse box model 1 the large scale canary basin circulation is estimated from a box inverse model applied to hydrographic data from a quasi synoptic survey carried out in september 2003 the cruise consisted of 76 full depth ctd and oxygen stations circulation is required to nearly conserve mass and anomalies of salinity and heat within layers bounded by neutral surfaces it permits advective and diffusive exchange between layers and an adjustment of the ekman transport and the freshwater flux divergences the canary current at the thermocline layer transports a net mass of 4 7 0 8 sv southward north of the canary islands from the african coast to 19 w it is divided into a northward circulation at a rate of 1 1 0 5 sv between the african coast and lanzarote island and a southward transport of 5 8 0 6 sv it transports north atlantic central water and organic matters advected offshore by the filaments protruding from the upwelling system off northwest africa at 24 n the canary current feeds the north equatorial current that transports a mixture of north and south atlantic central waters westward in the intermediate layer a southwestward flow of 1 2 1 1 sv transports mediterranean water to the subtropical gyre though the highest salt flux is transported by a meddy oxygen distribution and mass transport suggest a northeastward deep flow of a water mass colder than 2 2 c consisting of diluted antarctic bottom water the heat and freshwater divergences and the average dianeutral velocity and diffusion between the sections and the african coast are negligible

circulation patterns and transport of the azores front current system in this paper different types of new data sets hydrography lagrangian and eulerian current measurements and quasi geostrophic model results obtained after altimetric data assimilation are used to study the structure and variability of the azores current and frontal system the azores current was observed to transport between 11 0 and 18 0 sv eastwards and the associated counter current some 2 0 10 0 sv to the west resulting in a net value of about 8 9 sv furthermore both data and model results revealed a meandering azores current where some freely rotating eddies were also identified these hydrographic and lagrangian results exhibit space and time scales that agree fairly well with the dynamics shaped by baroclinic instability current meters moored across the azores current system delineated a mean counter current flowing westwards with a maximum subsurface core of about 2 0 cm s at a mean depth of 800 dbar this is in excellent agreement with previous studies which explains this azores counter current as the rectification process of the geostrophic turbulence occurring north of the main azores current stream a new scheme is proposed for the formation mechanism of the freely rotating cyclonic eddies observed south of the azores it is shown that the north south contrast thickness of the 17 19 c water layer across the azores front decreases downstream this will create in turn a downstream increase of the most unstable wavelength in a non linear baroclinic instability context as a consequence both large cyclonic and anticyclonic features are able to form at the eastern side of the azores current around 19 w while at the western side around 35 w only large anticyclones will survive western generated cyclones will be small enough to be quickly dissipated this means that the eastern cyclones of the azores current may live longer than the shorter western ones however because longer lived cyclonic eddies propagate westwards with a mean speed of 2 5 km day they may be observed south of azores and of the main stream several months later although they were not formed there

the lassell massif a silicic lunar volcano abstract lunar surface volcanic processes are dominated by mare producing basaltic extrusions however spectral anomalies landform morphology and granitic or rhyolitic components found in the apollo sample suites indicate limited occurrences of non mare geochemically evolved si enriched volcanic deposits recent thermal infrared spectroscopy high resolution imagery and topographic data from the lunar reconnaissance orbiter lro show that most of the historic red spots and other less well known locations on the moon are indeed silica rich relative to basalt here we present a geologic investigation of the lassell massif 14 65 s 350 96 e near the center of alphonsus a basin in mare nubium where high silica thermal emission signals correspond with morphological indications of viscous possibly also explosive extrusion and small scale low reflectance deposits occur in a variety of stratigraphic relationships multiple layers with stair step lobate forms suggest different eruption events or pulsing within a single eruption absolute model ages derived from crater size frequency distributions csfds indicate that the northern parts of the massif were emplaced at 4 ga before the surrounding mare however csfds also indicate the possibility of more recent resurfacing events the complex resurfacing history might be explained by either continuous resurfacing due to mass wasting and or the emplacement of pyroclastics relatively low reflectance deposits are visible at meter scale resolutions below detection limits for compositional analysis at multiple locations across the massif suggestive of pyroclastic activity a quenched flow surface or late stage mafic materials compositional evidence from 7 band uv vis spectral data at the kilometer scale and morphologic evidence for possible caldera collapse and or explosive venting support the interpretation of a complex volcanic history for the lassell massif

pristine lunar glasses criteria data and implications major element analyses of several thousand glasses from all of the apollo landing sites have resulted in the identification of 25 groups of pristine i e volcanic glass the nickel in these pristine glasses is shown to be indigenous not meteoritic contamination and to be correlated with mg the chemical data indicate that these glasses are consistently better candidates for primary magmas than the majority of crystalline mare basalts the pristine glasses support the view that assimilative processes ringwood and kesson 1976 involving two cumulate systems in the differentiated mantle operated during mare petrogenesis the reality of those assimilative interactions is evident by the occurrence of two linear arrays among the chemistries of the glasses data suggest that these cumulate components in the differentiated mantle persist for lateral distances of at least 1000 km and therefore appear to be products of a vast magma ocean that existed early in lunar history alternative hypotheses claiming that the highlands crust and mare source regions were produced by serial magmatism without a magma ocean have not yet considered all of the constraints derived from the pristine glasses

volcanic and impact deposits of the moon s aristarchus plateau a new view from earth based radar images lunar pyroclastic deposits reflect an explosive stage of the basaltic volcanism that filled impact basins across the nearside these fine grained mantling layers are of interest for their association with early mare volcanic processes and as possible sources of volatiles and other species for lunar outposts we present earth based radar images at 12 6 and 70 cm wavelengths of the pyroclastic deposit that blankets the aristarchus plateau the 70 cm data reveal the outlines of a lava flow complex that covers a significant portion of the plateau and appears to have formed by spillover of magma from the large sinuous rille vallis schroteri the pyroclastics mantling these flows are heavily contaminated with rocks 10 cm and larger in diameter the 12 6 cm data confirm that other areas are mantled by 20 m or less of material and that there are numerous patches of 2 cm and larger rocks associated with ejecta from aristarchus crater some of the radar detected rocky debris is within the mantling material and is not evident in visible wavelength images the radar data identify thick rock poor areas of the pyroclastic deposit best suited for resource exploitation

seasonal flow reversals of intermediate waters in the canary current system east of the canary islands two 9 yr current meter and salinity records together with climatological data reveal marked seasonal variability of the intermediate flow at a key location in the canary basin the region is characterized by a summer july september and early fall october northward progression of antarctic intermediate water followed by a fall november december intense flow reversal of mediterranean water a sverdrup type model confirms that these movements are associated with stretching or shrinking of the intermediate water strata

the source of the canary current in fall 2009 1 the source of the canary current has been inferred from an inverse box model applied to the hydrographic data of a survey carried out in 2009 in the northeast subtropical gyre 29 37 n 9 24 w the portugal current is observed between 13 5 and 14 8 w at 37 n carrying 1 8 0 4 sv southward this current presumably merges with the eastward transport of the azores current system and partly contributes to the mediterranean inflow and partly to the northward recirculation of the azores current through the gulf of cadiz the azores current system is located in the meridional range 33 50 36 25 n at 24 50 w this system transports eastward 7 2 0 5 sv in the thermocline layers and 1 1 0 8 sv at intermediate layers the azores current intermediate water mass has the highest portion of sub arctic intermediate water saiw in the region while the azores countercurrent intermediate waters mass is mainly mediterranean water the canary current extends from 22 25 to 18 50 w at 29 n the westernmost position ever observed this current transports southward 6 2 0 6 sv in the thermocline layers and 2 0 0 8 sv in the intermediate layers this intermediate flow shows a relative maximum of oxygen and a relative minimum in nutrient concentration indicating the presence of saiw the study concludes that at least in fall 2009 the canary current extends to the intermediate waters n 27 9220 approximately 1600 dbar and that azores current feeds the canary current at surface and intermediate layers

major element chemistry of the changjiang yangtze river the chemistry of major elements ca mg na k hco3 so4 cl and si in the river water of the changjiang yangtze river was studied based on continuously monitored data at 191 stations in the drainage basin for the period 1958 1990 the results show that the total dissolved solid tds concentration of the changjiang varies over an order of magnitude throughout the basin 49 7 518 1 mg l with a medium tds concentration of 205 9 mg l about three times the global average in contrast the tds at a given main channel station varies only slightly in different seasons with a variation factor less than 2 0 despite a substantial water dilution in the summer flood season the major element chemistry of the changjiang is mainly controlled by rock weathering with the anion hco3 and the cation ca dominating the major ion composition due to the abundance of carbonate rocks in the basin a persistently increasing trend has been observed in the concentrations of so4 and to a lesser extent cl in the changjiang a signature of considerable anthropogenic impacts e g acid deposition flux calculations at datong the most downstream main channel station without tidal influence indicate that the changjiang transports ca 154 106 tons year of tds to the sea second only to the amazon in the world

zonal circulation in the nw atlantic and caribbean from a meridional world ocean circulation experiment hydrographic section at 66 w a world ocean circulation experiment hydrographic program section along 66 w in the north atlantic was made in 1997 in addition to the usual variables hydrographic and tracer measured in woce onetime sections we made lowered acoustic doppler current profiler ladcp measurements at nearly all of the stations the section closed off a portion of the western north atlantic to the west of the line making a closed volume for constraining the circulation in addition the deep portions of the caribbean do not communicate with the rest of the basin by combining mass silica and ladcp information as constraints an inverse calculation obtained reveals a strong eastward transport in the gulf stream bounded by westward flowing water on either side within these energetic flows we see evidence for recently ventilated classical labrador sea water which has not reached the deep western boundary current north of puerto rico in any significant amounts within the caribbean our major new finding is a deep cyclonic circulation below sill depth in excess of 100 times the inflow of deep atlantic water through the major deep sill the anegada jungfern passage the signature of the deep atlantic source water is most prominent in cfcs and both a bottom and mid depth maximum are present in the caribbean to the south of puerto rico off the coast of venezuela however only the deeper cfc maximum is found for the entire section the net overturning circulation heat flux and freshwater fluxes are all consistent with expectations based on water mass formation and air sea exchanges to the west of our section but the annual mean air sea fluxes of heat and freshwater from comprehensive ocean atmosphere data sets appear somewhat too small in comparison with our single section result

surface circulation in the gulf of cadiz model and mean flow structure 1 the mean flow structure of the gulf of cadiz is studied using a numerical model the model consists of a set of one way nested configurations attaining resolutions on the order of 2 6 km in the region of the gulf of cadiz in the large scale configuration the entrainment of the mediterranean water is parameterized implicitly through a nudging term in medium and small scale nested configurations the mediterranean outflow is introduced explicitly the model reproduces all the known features of the azores current and of the circulation inside the gulf of cadiz a realistic mediterranean undercurrent is generated and meddies develop at proper depths on the southwest tip of the iberian slope the hypothesis that the azores current may generate in association with the mediterranean outflow plume theories is confirmed by the model results the time mean flow is dominated by a cyclonic cell generated in the gulf which expands westward and has transports ranging from 4 to 5 sv the connection between the cell and the azores current is analyzed at the scale of the gulf the time mean flow cell is composed by the westward mediterranean undercurrent and by a counterflow running eastward over the outer edge of the mediterranean undercurrent deeper vein as the latter is forced downslope this counterflow feeds the entrainment at the depths of the mediterranean undercurrent and the atlantic inflow at shallower levels coastward and upslope of this recirculation cell a second current running equatorward all the way along the northern part of the gulf is revealed this current is a very robust model result that promotes continuity between the southwestern iberian coast and the strait of gibraltar and helps explain many observations and recurrent sst features of the gulf of cadiz

zonal structure of the mean flow and eddies in the azores current system 1 the surface circulation and eddy field from the azores current system are studied here by analyzing surface drifters records and altimetry maps collected over more than 16 years clear differences in mean flow and eddy characteristics allow for a classification of the azores current in three zonal sectors west of 30 w between the mid atlantic ridge and the hyeres atlantis seamount system between 30 w and the longitude of madeira and east of madeira a detailed and quantitative characterization of each sector is given the transition between the western and central parts is controlled by the hyeres atlantis ridge in the transition to the eastern sector there is a change in the dynamics and the flow is forced by the cyclonic recirculation driven by the mediterranean outflow there is no clear expression of a continuous surface northern counterflow but three distinct westward flows are seen one along the southeastern border of the azores plateau another one southwest of madeira and a third one along 31 n west of the hyeres seamount no clear tilt in the axis of the azores current is found in the calculated mean surface flow from surface drifters observations from both drifters and altimetry data show that anticyclonic features dominate in the northern region whereas cyclonic ones dominate in the southern region overall cyclones are more numerous constituting 60 of large eddies the eddy features detected in the west tend to be larger than those in the east both in size and sea level anomaly there is indication of different mean propagation speeds east and west of 25 w 30 w with the mean speeds consistently increasing by 25 45 in the west estimates for the rate of formation of strong eddies range from 1 4 to 2 4 year 1 for cyclones and 1 2 to 1 7 year 1 for anticyclones

lunar regional dark mantle deposits geologic multispectral and modeling studies clementine five channel uv visible uvvis data have been used to study seven regional dark mantle deposits dmds on the moon the dmds were mapped in distribution to determine their extent and stratigraphic relationship to other geologic units based upon the spectral properties for each dmd the crystallization of the beads in each deposit was inferred and used to estimate cooling rates in the volcanic plumes that emplaced the deposits deposits with a high concentration of glasses reflect volcanic plumes that had low optical densities and high cooling rates whereas deposits dominated by crystallized beads indicate plumes with slower cooling rates due to higher optical densities spectral data from each of the regional dmds show that their glass crystallized bead ratio can be estimated based upon their 415 750 and 750 950 nm values and comparison to laboratory spectra for the beads patches of young dark mantle in the sinus aestuum dmd represent one extreme with the bluest color highest 415 750 and weakest glass band absorption lowest 750 950 of all the dmds at the other extreme is the aristarchus plateau dmd with the reddest color and strongest glass band absorption the other nearside dmds including taurus littrow sulpicius gallus rima bode and mare vaporum lie between these two extremes due to intermediate mixtures of the crystallized beads and glasses with other local soils the orientale ring dmd on the western limb is dominated by volcanic glasses and is spectrally similar to the localized dmds found in alphonsus crater we have identified a central vent for the orientale ring dmd and model the eruption as degassing of a near surface dike to produce a 20 km high umbrella shaped plume with ejection velocities of 360 m s and deposition of the glasses at an average radius of 80 km from the vent although we cannot identify the exact sources for the other regional dmds probably because they are buried beneath younger mare the eruptions most likely resulted from dikes breaching the surface and producing a volcanic plume dominated by larger greater than submillimeter hot clasts that formed mare and sinuous rules the small percent of clasts that form the volcanic beads are carried by the expanding gas cloud to large distances in some cases 100 km to produce the observed continuous regional dmds the lack of basalt samples that can be petrologically related to the volcanic glasses may be a result of their spatial separation with the basalts flowing into the basins while the beads are deposited both into the basins and on the adjacent highlands

spectral properties of the marius hills volcanic complex and implications for the formation of lunar domes and cones we have used multispectral data from the clementine uv visible camera to study the volcanic features of the marius hills complex and their comparison to other lunar domes and cones there are several mare units identified in the complex each with a unique ti content as indicated by their 415 750 nm value the domes in marius hills are spectrally identical to the mare plains of the complex supporting similar compositions in contrast most of the volcanic cones of the complex are lower in reflectance bluer in color and have weaker mafic absorptions than the mare and domes the spectral characteristics of the cones can best be explained by fine grained crystallization in the spatter that compose the cones other lunar cones such as mons esam in northern tranquillitatis have spectral properties similar to those at marius hills the rima parry cones and their associated dark mantle deposit appear redder with a stronger mafic absorption than the marius hills cones the cones isis and osiris in southern mare serenitatis the domes of rumker hills and several domes in northern mare tranquillitatis are spectrally similar to adjacent mare units the mairan and gruithuisen domes in northern oceanus procellarum have a feldspathic signature characteristic of highland material although they are redder and brighter than adjacent highland soils they appear to represent highland material that resembles domes rather than actual mare domes like those at marius and rumker hills the diversity of lunar volcanic features can best be explained by differences in accumulation rates and cooling of ejected clasts from various eruption styles mare domes may have formed at lower effusion rates thereby allowing lava to construct small shields with slopes 3 the steeper domes at marius hills require higher viscosities resulting from even lower effusion rates and enhanced crystallization in the magmas during the terminal stages of earlier eruptions that emplaced the mare cones like mons esam rima parry isis and osiris are aligned along linear rilles and are interpreted to result from degassing of near surface dikes in contrast the cones of marius hills show no linear alignment and may result from strombolian eruptions at the terminal stages of earlier effusive eruptions that emplaced the domes and mare in the complex

a view of the canary basin thermocline circulation in winter during january and february 1989 the recirculation of the subtropical gyre in the eastern north atlantic was surveyed with a three ship experiment the analysis of hydrographic measurements and velocity data from a shipboard acoustic doppler current profiler reveals the synoptic scale circulation patterns and water mass distributions in the canary basin the geostrophic transport stream function estimated with a horizontally varying reference level of no motion highlights the major currents in three layers representing the vertical structure of the horizontal circulation the classical circulation scheme is shown by the stream function in the upper 200 m the azores canary and north equatorial currents unlike the deep penetrating azores current the canary current and the north equatorial current are restricted to the upper 200 m both carry north atlantic central water along the water mass boundary with south atlantic central water south atlantic central water flows through the passage between the cape verde archipelago and africa via narrow currents into the area north of 14 5 n at the southern edge of the subtropical gyre we identify an eastward flow of antarctic intermediate water between 700 and 1200 m

an investigation of potential pyroclastic deposits on the southeast limb of the moon abstract we investigated the physical and spectral properties of potential dark mantling deposits pdmds previously and newly identified on the se limb of the moon near the craters humboldt and petavius the goals of this investigation were to constrain the composition and mode of emplacement of these poorly studied deposits to identify interdeposit variations and to use these results to draw conclusions about regional and subsurface geologic processes our investigation involved an assessment of both the physical properties size texture morphology and spectral properties albedo absorption bands color ratios utilizing remote sensing data from multiple lunar orbital missions we found that many of the se limb deposits previously identified as possibly pyroclastic in origin were likely effusively emplaced however we also identified several likely pyroclastic deposits including three not previously mapped we found that the volcanic deposits across the study area comprise three major spectral groups one similar to mare fecunditatis one similar to mare australe and one similar to known glassy pyroclastic deposits elsewhere on the moon we conclude that volcanism across the se limb was likely fed from at least two distinct magma source regions and that the type and extent of surface expression of this volcanic activity was possibly influenced by regional variations in crustal thickness our documentation and analysis of the complex volcanic history in this region of the moon supports ongoing efforts to develop increasingly detailed interpretations of the volcanic history of the entire moon

dark ring in southwestern orientale basin origin as a single pyroclastic eruption 1 a large 154 km diameter dark annular ring located in the southwestern part of the orientale basin along the montes rook ring was first discovered and documented in soviet zond 8 images clementine uv visible multispectral data indicate that the dark ring consists of material similar to the pyroclastic glasses collected by the apollo astronauts with the glasses being more closely related to the orange glass beads that comprise the aristarchus plateau than to the crystallized black beads typical of taurus littrow this implies relatively rapid cooling times for the eruption products we propose that the dark ring is the manifestation of a pyroclastic eruption originating at a fissure vent an elongate 7 5 km by 16 km depression located near the center of the ring the event producing the eruption began with a dike rapidly emplaced from subcrustal depths to within 3 4 km of the surface the dike stabilized and degassed over 1 7 years to form an upper foam layer which then penetrated to the surface to cause an eruption lasting 1 2 weeks the eruption produced a 38 km high symmetrical spray of pyroclasts into the lunar vacuum at velocities of 350 to 420 m s and the pyroclastic material accumulated in a symmetrical ring around the vent the geometry of eruption caused the deposits to accumulate preferentially in a ring representing the material ejected at 45 the paucity of pyroclastic rings of this type on the moon can be attributed to the low probability of a dike stalling at just the right depth 3 4 km to create these eruption conditions the detailed characteristics of this ring provide important new insight into the emplacement of pyroclastics in the more regionally continuous lunar dark mantle deposits suggesting that their sources are dominated by effusive and hawaiian style eruptions the orientale dark ring deposit has similarities to the pyroclastic rings on the galilean satellite io both the orientale dark ring and ionian eruptions involve acceleration of small particles to a high velocity in an expanding gas stream silicate pyroclasts derived from the disrupted foam layer in the lunar case and a mixture of silicate pyroclasts and snowflakes of condensing so2 solids on io in both cases the silicate pyroclasts ejected from the vent are accelerated by the gas until they become decoupled and continue on ballistic trajectories controlled only by gravity differences in mass flux and cloud opacity between the moon and io are the direct result of the origin and mass fraction of the volatile phase the accumulation of a magmatic foam layer on top of a silicate intrusion in the lunar case and the intimate mixing on io of a steadily erupting magma and liquid so2 the interpretation of the orientale dark mantle ring as a pyroclastic eruption provides an alternative to the hypothesis that the dark ring represents the presence of an ancient pre orientale impact structure and that the orientale basin cavity of excavation must therefore lie within the outer rook mountain ring

lunar mare volcanism stratigraphy eruption conditions and the evolution of secondary crusts abstract lunar mare basalt deposits cover 17 of the lunar surface occur preferentially in topographic lows on the nearside and have a total volume estimated at 1 107 km3 analysis of returned samples and photogeologic and remote sensing studies shows that mare volcanism began prior to the end of heavy bombardment the period of cryptomare formation in pre nectarian times and continued until the copernican period a total duration approaching 3 5 4 ga stratigraphic analyses show that the flux was not constant but peaked in early lunar history during the imbrian period which spans the period 3 85 3 2 ga average volcanic output rate during this peak period was about 10 2 km 3 a very low relative to the present global terrestrial volcanic output rate and comparable to the present local output rates for individual volcanoes such as vesuvius and kilauea hawaii volcanic landforms indicate that many eruptions were of high volume and long duration some eruptions associated with sinuous rules may have lasted of the order of a year and emplaced 103 km3 of lava representing the equivalent in one year of about 70 000 years at the average flux shallow magma chambers were uncommon the nearsidefarside mare deposit asymmetry can be readily explained by differences in crustal thickness magma ascending from the mantle or from a buoyancy trap at the base of the crust should preferentially extrude to the surface on the nearside but should generally stall and cool in dikes in the farside crust extruding only in the deepest basins the occurrence of farside maria within craters whose diameter is generally near to or less than the thickness of the crust may be accounted for by the difference between local and regional compensation dikes that establish pathways to the surface on the nearside should have very high volumes comparable to the volumes associated with many observed flows and sinuous rilles an abundance of dikes should exist in the lower crust of the moon many more than those feeding surface eruptions the upper limit is 37 50 of the crust by volume the presence and abundance of such dike swarms have important implications for the interpretation of the average composition of the lunar crust and the composition of basin and crater ejecta the interplay between thermal contraction and differentiation leads to net cooling and ultimate contraction of the outer portions of the moon resulting in a regional horizontal compressive stress acting on the lunar crust in addition overall cooling and deepening of sources require the production of ever larger volumes of magma in order to reach the surface with time stresses became high enough so that few dikes could open to the surface causing eruptive activity to be severely diminished in the eratosthenian and perhaps to cease in the copernican period lower stress levels are required to terminate eruptive activity on the lunar farside consistent with the imbrian age of the farside maria and the nearside location of the youngest maria lunar mare deposits provide an example of the transition from primary crusts to secondary crusts and illustrate the significance of several factors in the evolution of secondary crusts such as crustal density variations in crustal thickness presence of impact basins state and magnitude of stress in the lithosphere and general thermal evolution these factors are also responsible for the extremely low volcanic flux even during periods of peak extrusion

large scale mass transports water mass formation and diffusivities estimated from world ocean circulation experiment woce hydrographic data 1 a global inversion is used to estimate the oceanic mass transports and vertical diffusivities based on a subset of hydrographic data from the world ocean circulation experiment woce and java australia dynamic experiment the analysis is based on the linear inverse box model of ganachaud and wunsch 2000 that consistently combines the transoceanic sections a globally consistent solution is obtained for a depth independent adjustment to the thermal wind field the freshwater flux divergences the ekman transport and the advective and diffusive dianeutral fluxes between layers a detailed error budget permits calculation of statistical uncertainties taking into account both the nonresolved part of the solution and the systematic errors due to the temporal oceanic variability the horizontal structure of the transports for different density classes is analyzed regionally during the woce period 1985 1996 net meridional transports are estimated with 16 2 sv 106 m3 s of north atlantic deep water nadw being produced in the northern north atlantic moving southward entraining antarctic bottom water aabw and antarctic intermediate water increasing in volume transport to 23 3 sv at 30 s in the southern ocean 21 6 sv of bottom water was formed from lower circumpolar deep water which corresponds approximately to the lower nadw density range bottom water inflows nadw aabw mixture to the atlantic indian and pacific oceans are estimated at 6 1 3 11 4 and 7 2 sv respectively in the indian and pacific oceans this water returns southward at deep and intermediate levels property anomaly conservation constraints permit estimation of dianeutral diffusivities in deep layers with a global average of 3 7 0 7 cm2s 1 north of 30 s

compositional analyses of lunar pyroclastic deposits abstract the 5 band clementine uvvis data at 100 m pixel were used to examine the compositions of 75 large and small lunar pyroclastic deposits lpds and these were compared to representative lunar maria and highlands deposits results show that the albedo spectral color and inferred composition of most lpds are similar to those of low titanium mature lunar maria these lpds may have consisted largely of fragmented basalt with substantial components of iron bearing mafic minerals pyroxenes olivine and smaller amounts if any of volcanic glass several smaller lpds also show substantial highland components three classes of very large deposits can be distinguished from most lpds and from each other on the basis of crystallinity and possible titanium content of their pyroclastic components one class has spectral properties that are dominated by high titanium crystallized black beads e g taurus littrow a second consists of a mixture of high titanium glasses and beads with a higher glass bead ratio sulpicius gallus than that of taurus littrow and a third has a significant component of quenched iron bearing volcanic glasses aristarchus with possible moderate titanium contents although areally extensive these three classes of very large pyroclastic deposits compose only 20 of the 75 deposits studied 27 and eruption of such materials was thus likely to have been less frequent on the moon

mineralogy of the lunar crust results from clementine received 1997 december 5 accepted in revised form 1998 september 15 abstract the central peaks of 109 impact craters across the moon are examined with clementine ultraviolet visible uvvis camera multispectral data the craters range in diameter from 40 to 180 km and are believed to have exhumed material from 5 30 km beneath the surface to form the peaks including both upper and lower crustal rocks depending on whether craters have impacted into highlands or basins representative five color spectra from spectrally and spatially distinct areas within the peaks are classified using spectral parameters including key ratio which is related to mafic mineral abundance and spectral curvature linked to absorption band shape which distinguishes between low and high ca pyroxene and olivine the spectral parameters are correlated to mineralogical abundances related in turn to highland plutonic rock compositions the derived rock compositions for the various central peaks are presented in a global map from these results it is evident that the lunar crust is compositionally diverse both globally and at local 100 m scales found within individual sets of central peaks although the central peaks compositions imply a crust that is generally consistent with previous models of crustal structure they also indicate a more anorthositic crust than generally assumed with a bulk plagioclase content of 8 1 evolving from pure anorthosite near the surface towards more mafic low ca pyroxene rich compositions with depth comparable to anorthositic norite evidence for mafic plutons occurs in both highlands and basins and represent all mafic highland rock types however the lower crust is more compositionally diverse than the highlands with both a greater range of rock types and more diversity within individual sets of central peaks

large and mesoscale variability of the water masses and the deep chlorophyll maximum in the azores front 1 coupling between the physical and biological fields in the upper ocean around the azores front af was studied in summer 1998 during an oceanographic cruise to the southern azores islands 30 n 38 n and 20 w 33 w on the basis of conductivity temperature depth ctd acoustic doppler current profiler adcp and fluorescence data several large scale mesoscale and submesoscale physical features are described the adcp data and geostrophic field revealed an eastward transport associated with the azores current ac and weak countercurrents to the south and north of the ac the water mass field shows a strong latitudinal variation in the af with an eastward modification from the surface to 300 dbar the saline distribution strongly defined the af as a very sharp vertical front the horizontal thermohaline gradient increased to the east and reached a maximum at approximately 150 dbar the 16 2 c isotherm and 36 2 isohaline at 150 dbar precisely located the af along the whole area in agreement with the dynamic field to the west of 26 w the azores current was 140 km wide while the af was only 15 25 km wide to the east of 26 w the ac underwent a strong meandering the water mass characteristics in the southern part of the af show an eastward evolution between 18 c seawater and madeira mode water data from a ctd fluorometer mounted on an undulator system allowed the small scale structure of af to be mapped describing several eddies and meanders the deep chlorophyll maximum dcm showed highest values 0 9 to 1 2 mg chl m 3 toward the west 32 w on the southern side of the af chlorophyll concentrations at the dcm 0 4 0 6 mg chl m 3 on the northern side of the study area were moderate and fairly constant whereas low values 0 3 mg chl m 3 were measured at the very deep dcm 120 140 m in the southeast associated with high saline waters examination of a cold eddy showed similar chlorophyll concentrations to those found on the northern side of the af the thermohaline structure of the eddy was similar to the af with northern water enclosed within saline and warm southern water

the azores current system from a meridional section at 24 5 w 1 high spatial resolution hydrographic data including lowered acoustic doppler current profiler ladcp measurements were acquired along a meridional section at 24 5 w in october 2009 the data are analyzed in detail with the purpose of definitively defining and quantifying the zonal azores current system the azores current and azores countercurrent are delimited each extending meridionally for 110 km the azores current is located between 33 5 n and 34 5 n flanked to the north by the azores countercurrent 35 25 36 25 n vertically both currents reach the n 27 975 kg m 3 level 2000 m depth their mass transports ranging across thermocline as well as intermediate layers the azores current transports 13 9 sv 1 sv 106 m3 s 1 109 kg s 1 eastward with its maximum associated with the azores front 33 75 n the azores countercurrent flows below the surface transporting 5 5 sv westward this contributes to a net eastward flow of 8 4 sv across the section at intermediate layers the azores countercurrent transports mixed mediterranean water to the west and the azores current transports mixed sub arctic intermediate water to the east shipboard adcp and satellite derived geostrophic velocity are used to confirm the transports revealed by the hydrographic data

clementine observations of the aristarchus region of the moon multispectral and topographic data acquired by the clementine spacecraft provide information on the composition and geologic history of the aristarchus region of the moon altimetry profiles show the aristarchus plateau dipping about 1 to the north northwest and rising about 2 kilometers above the surrounding lavas of oceanus procellarum to the south dark reddish pyroclastic glass covers the plateau to average depths of 10 to 30 meters as determined from the estimated excavation depths of 100 to 1000 meter diameter craters that have exposed materials below the pyroclastics these craters and the walls of sinuous rilles also show that mare basalts underlie the pyroclastics across much of the plateau near infrared images of aristarchus crater reveal olivine rich materials and two kilometer sized outcrops of anorthosite in the central peaks the anorthosite could be either a derivative of local magnesium suite magmatism or a remnant of the ferroan anorthosite crust that formed over the primordial magma ocean

a sharper view of impact craters from clementine data the ultraviolet visible camera on the clementine spacecraft obtained high spatial resolution images of the moon in five spectral channels impact craters mapped with these multispectral images show a scale of lithologic diversity that varies with crater size and target stratigraphy prominent lithologic variations feldspathic versus basaltic occur within the south wall of copernicus 93 kilometers in diameter on the scale of 1 to 2 kilometers lithologic diversity at tycho 85 kilometers in diameter is less apparent at this scale although the impact melt of these two large craters is remarkably similar in this spectral range the lunar surface within and around the smaller crater giordano bruno 22 kilometers in diameter is largely dominated by the mixing of freshly excavated material with surrounding older soils derived from a generally similar feldspathic lithology

seasonal variability of the canary current a numerical study 1 a high resolution numerical model study of the canary basin in the northeast subtropical atlantic ocean is presented a long term climatological solution from the regional oceanic modeling system roms reveals mesoscale variability associated with the azores and canary current systems the northwest african coastal upwelling and the canary island archipelago the primary result concerns the canary current canc which in the solution transports 3 sv southward in line with observations the simulated canc has a well defined path with pronounced seasonal variability this variability is shown to be mediated by the westward passage of two large annually excited counterrotating anomalous structures that originate at the african coast the anomalies have a sea surface expression permitting their validation using altimetry and travel at the phase speed of baroclinic planetary rossby waves the role of nearshore wind stress curl variability as a generating mechanism for the anomalies is confirmed through a sensitivity experiment forced by low resolution winds the resulting circulation is weak in comparison to the base run but the propagating anomalies are still discernible so we cannot discount a further role in their generation being played by annual reversals of the large scale boundary flow that are known to occur along the african margin an additional sensitivity experiment where the azores current is removed by closing the strait of gibraltar presents the same anomalies and canc behavior as the base run suggesting that the canc is rather insensitive to upstream variability from the azores current

new insight into lunar impact melt mobility from the lro camera 1 the lunar reconnaissance orbiter camera lroc is systematically imaging impact melt deposits in and around lunar craters at meter and sub meter scales these images reveal that lunar impact melts although morphologically similar to terrestrial lava flows of similar size exhibit distinctive features e g erosional channels although generated in a single rapid event the post impact mobility and morphology of lunar impact melts is surprisingly complex we present evidence for multi stage influx of impact melt into flow lobes and crater floor ponds our volume and cooling time estimates for the post emplacement melt movements noted in lroc images suggest that new flows can emerge from melt ponds an extended time period after the impact event

the compositional and physical properties of localized lunar pyroclastic deposits abstract lunar localized pyroclastic deposits are low albedo deposits with areas 2 these deposits were difficult to study before the turn of the millennium because of the lack of available high spatial resolution data with the launch of the lunar reconnaissance orbiter kaguya and chaandrayan 1 new sets of diverse high spatial resolution data are now available using several of these data sets we conducted a study of 34 localized pyroclastic deposits globally for each localized pyroclastic deposit we examined topography to estimate pyroclastic volume and juvenile proportions s band radar backscatter thermal infrared derived measures of surficial rock abundance and regolith density and mineral abundances our goals are to 1 quantitatively characterize the physical and mineralogical properties of each localized pyroclastic deposit 2 investigate the physical and mineralogical variations among localized pyroclastic deposits 3 compare these properties of localized 2 to regional pyroclastic deposits 2500 km 2 and 4 provide useful parameters for future volcanological modeling from this study we find that 1 localized pyroclastic deposits exhibit low relief structures 2 the surface rock abundance and circular polarization ratio of localized pyroclastic deposits display a wide range of values 0 2 0 5 and 0 3 0 6 respectively 3 the glass abundance of localized pyroclastic deposits vary between 0 and 80 wt 4 there are four types of localized pyroclastic deposits based upon the surface rock abundance and glass abundance parameters 5 pyroclastic deposits within the same floor fractured crater tend to have similar properties and 6 localized pyroclastic deposits are diverse with respect to regional pyroclastic deposits but a subset of localized pyroclastic deposits have similar physical and mineralogical properties to regional pyroclastic deposits

39ar 40ar ages for the apollo 15 green and yellow volcanic glasses a technique using the laser microprobe to extract noble gases from individual small 100 750 m in diameter low potassium 0 09 wt k2o glassy samples was developed this technique has an advantage in that an individual sample can be chemically characterized by an electron microprobe and then analyzed for its argon age thus eliminating any ambiguities in the classification of the sample and the need for large quantities of samples this technique was then used to study the argon isotopes and apparent 39ar 40ar ages of three varieties of volcanic glass from apollo 15 yellow volcanic green volcanic group a and green volcanic group d the apparent solidification age for the glasses are 3 62 0 07 3 41 0 12 and 3 35 0 18 aeons respectively the ages for group a and d green glasses agree well with previously reported ages for aliquots of bulk green glass a value of 40ar 36arsw 0 5 0 5 was used to correct the data since a 40ar 36arsw versus 39ark 36arsw plot failed to identify a well defined trapped component no significant difference in the solidification age 0 2 aeons was found between the a and d groups of the volcanic green glasses these ages for volcanic glasses are consistent with the prediction of delano and livi 1981 that array ii volcanic glasses are generally older 3 6 aeons than array i glasses the average exposure ages for the apollo 15 yellow volcanic and green volcanic groups a and d glasses from 15426 and 15427 were indistinguishable with ages between 300 and 275 m y

meandering of the subtropical front south east of the azores a subtropical front was observed in the area south and southeast of the azores during cruises of fs meteor and fs poseidon in early 1982 the front has a basically west east extension with considerable meandering observed meso scale eddies are found on both sides the overall flow pattern corresponds to earlier results on geopotential differences in the upper northeast atlantic but the baroclinic transport of the order of 107 m3 s 1 is found to be concentrated in a 60 km wide jet we suggest here that the current band is part of the gyre circulation resulting from a branching of the north atlantic current

the canary basin contribution to the seasonal cycle of the atlantic meridional overturning circulation at 26 n this study examines the seasonal cycle of the atlantic meridional overturning circulation amoc and its eastern boundary contributions the cycle has a magnitude of 6 sv as measured by the rapid mocha wbts project array at 26 n which is driven largely by the eastern boundary the eastern boundary variations are explored in the context of the regional circulation around the canary islands there is a 3 month lag between maximum wind forcing and the largest eastern boundary transports which is explained in terms of a model for rossby wave generated at the eastern boundary two dynamic processes take place through the lanzarote passage lp in fall the recirculation of the canary current and the northward flow of the intermediate poleward undercurrent in contrast during the remaining seasons the transport through the lp is southward due to the canary upwelling current these processes are linked to the seasonal cycle of the amoc

basaltic magmatism on the moon a perspective from volcanic picritic glass beads abstract it is widely accepted that basaltic magmas are products of partial fusion of periodotite within planetary mantles as such they provide valuable insights into the composition structure and processes of planetary interiors those compositions which approach primary melt compositions provide the most direct information about planetary interiors and serve as a starting point to understand basaltic evolution within the collection of lunar samples returned by the apollo and luna missions are homogeneous picritic glass beads of volcanic origin these picritic glasses are our closest approximations to primary magmas as such these glass beads provide a unique perspective concerning the origin of mare basalts the characteristics of the lunar interior and processes in the early differentiation of the moon we have obtained trace element data for these picritic glasses using sims techniques these data and literature isotopic and experimental data on the picritic glasses are placed within the framework of mare basaltic magmatism the volcanic glasses are very diverse in their trace element characteristics for example they have a wide range of ree pattern shapes and concentrations like the crystalline mare basalts all picritic glasses have a negative eu anomaly unlike the crystalline mare basalts there is little correlation between the size of the eu anomaly and overall ree concentrations trace element differences among the various glasses suggests that a kreep component was incorporated into their mantle source this implies large scale mixing of the lunar magma ocean derived cumulate pile subtle differences among glasses suggest that local mixing of sources may also have been an important process preservation of subtle chemical differences in the picritic glasses and crystalline basalts may be interpreted as indicating that they were produced by small to moderate degrees of partial melting and that the lunar mantle did not experience extensive melting during episodes of mare volcanism several lines of evidence are consistent with the view that the picritic glasses were derived from mantle sources that were compositionally distinct from the sources for crystalline mare basalts these are parallel but no common liquid lines of descent chemical differences between picritic glasses and the more primitive crystalline mare basalts experimental studies indicating that the picritic glasses are multiply saturated at depths greater than that of the mare basalts differences in lead isotopic data and the mode of eruption i e fire fountaining for glass beads these data also provide circumstantial evidence that suggests that the picritic glasses were derived from a source somewhat more volatile rich than that of the mare basalts several petrogenetic models are suggested by the trace element characteristics of the picritic glasses 1 1 partial melting of heterogeneous lunar mantle at depths greater than 300 km to produce the parental magmas picritic for both the mare basalts and picritic glasses picritic magmas represented by glass beads were erupted to the surface with small degrees of fractional crystallization while mare basalts were produced by larger degrees of fractional crystallization 15 30 of similar but not identical picritic magmas 2 2 picritic magmas represented by the glass beads were generated at depths greater than 400 km in a volatile enriched relative to the mare basalt source heterogeneous mantle while mare basalts are fractional crystallization products of picritic magmas generated at depths of less than 400 km 3 3 the picritic magmas represented by the glass beads represent polybaric melting that initiated at depths of at least 1000 km a primitive mantle component or less processed cumulate mantle components may have been involved in the generation of the picritic glasses in any of these models

radar remote sensing of pyroclastic deposits in the southern mare serenitatis and mare vaporum regions of the moon 1 we use polarimetric radar observations to study the distribution depth and embedded rock abundance of nearside lunar pyroclastic deposits radar images were obtained for mare vaporum and the southern half of mare serenitatis the imaged areas contain the large rima bode mare vaporum sulpicius gallus and taurus littrow pyroclastic deposits potential pyroclastic deposits at rima hyginus crater the tacquet formation and a dome in mare vaporum are also included data were acquired at s band 12 6 cm wavelength using arecibo observatory and the green bank telescope in a bistatic configuration the s band images have resolutions between 20 and 100 m pixel the pyroclastic deposits appear dark to the radar and have low circular polarization ratios at s band wavelengths because they are smooth easily penetrable by radar waves and generally contain few embedded blocks changes in circular polarization ratio cpr across some of the pyroclastic deposits show areas with increased rock abundance as well as deposits that are shallower radar backscatter and cpr maps are used to identify fine grained mantling deposits in cases where optical and near infrared data are ambiguous about the presence of pyroclastics the tacquet formation in southern serenitatis areas near hyginus crater and a dome in mare vaporum have lower backscatter cross sections than would be expected for mare basalts of similar estimated titanium content combined with very low cpr values this is strong evidence that these areas are covered in fine grained pyroclastic mantling material

on the reasons for the formation and variability of the azores current abstract recent studies have shown that the formation of the well defined zonally oriented azores current may be the result of water mass transformation associated with the mediterranean outflow in the gulf of cadiz as the denser mediterranean water descends down the continental slope it entrains overlying north atlantic central water it is believed that the azores current then forms as part of the horizontal recirculating gyre generated through the plume mechanism in this study the authors further explore this hypothesis by performing a series of numerical experiments these experiments are based on a high resolution general circulation model that includes the mediterranean sea and that realistically simulates the water mass exchange through the strait of gibraltar and the transport and variability of the azores current the authors show that the divergence of the relative vorticity flux and the planetary vorticity flux associated with planetary waves are the main factors determining the variab

on the origin of the azores current the azores current south of the azores archipelago is part of the subtropical north atlantic gyre using an international hydrographic data set we analyze mean and seasonal geostrophic transport fields in the upper 800 m of the ocean in order to determine the origin of the azores current in the western basin and seasonal changes in the related flow geostrophic currents are obtained by using the method applied by stramma 1984 in the eastern basin the azores current is found to originate in the area of the southwest newfoundland rise figure 10 in winter an almost uniform current connects this region of origin with the azores current while a branching into two current bands is observed in summer with the southern band forming a marked cyclonic loop within the upper 800 m all of the transport in the northern band and about 70 of the transport in the southern band recirculates in the eastern basin additionally expendable bathythermograph data from the azores current region indicate an increase of eddy potential energy from winter to summer

the water masses of the central north atlantic in 1983 84 abstract hydrographic surveys carried out in 1983 84 along both sides of the mid atlantic ridge between 24 and 53 n provide a detailed description of the well known north atlantic water masses with particular emphasis on their meridional distribution and zonal dissymetry in the upper layers the dense horizontal sampling resolves the several narrow gulf stream extensions into the ocean interior giving the image in the central water density range of a mosaic of mode waters separated by fronts at intermediate depths a vertical shear in the distributions of the mediterranean water and labrador sea water stands out both water masses having their lower part displaced southwards relative to their upper parts bottom waters containing nearly 20 percent of pure antarctic bottom water are observed at 50 n in the eastern basin in contrast with the western basin where proportions greater than 10 percent were found only south of 36 n along our section this water mass analysis also gives indications that stron

mixing and spreading of the mediterranean outflow abstract hydrographic and current profiler data taken during the 1988 gulf of cadiz expedition have been analyzed to diagnose the mixing spreading and descent of the mediterranean outflow the s properties and the thickness and width of the outflow were similar to that seen in earlier surveys the transport of pure mediterranean water i e water with s 38 4 psu was estimated to be about 0 4 106 m3 s 1 which is lower than historical estimates most of which were indirect but comparable to other recent estimates made from direct velocity observations the outflow transport estimated at the west end of the strait of gibraltar was about 0 7 106 m3 s 1 of mixed water and the transport increased to about 1 9 106 m3 s 1 within the eastern gulf of cadiz this increase in transport occurred by entrainment of fresher north atlantic central water and the salinity anomaly of the outflow was consequently reduced the velocity weighted salinity decreased to 36 7 psu within 60 km of the strait and decre

physical oceanography of the azores front abstract there is a considerable body of evidence for the existence of a permanent front sw of the azores surveys in the summer of 1981 show the structure to penetrate to a depth of 2 000 m and suggest that its meandering is related to the alignment of the atlantis gt meteor seamount chain the total volume transport above 2 000 m is between 10 and 12 106 m3 s 1 towards the east the main water mass contrasts across the front are confined to the upper 400 m of the water column only a small change in mediterranean water strength was seen across the front satellite tracked drogued buoys seeded into the front showed surface speeds of up to 40 cm sec 1 and revealed the formation of a closed cold core eddy some 100 115 km in diameter which propagated westward at 2 2 km day 1 over a 200 day period sea surface temperature contrasts across the frontal boundary are small and together with frequent cloud cover prevent the detection of the front and associated eddies by satellite infra red imagery the front apparently marks the eastward extension of the southern branch of the gulf stream recirculation and the northern limit of the 18 c water mass eddies formed at the front could propagate westward into the interior of the sargasso sea but have not yet been observed to cross the mid atlantic ridge

quasi synoptic transport budgets and water mass transformation in the azores gibraltar strait region during summer 2009 abstract we describe the circulation patterns in the azores gibraltar strait region north eastern atlantic during the 2009 caibox cruise on the basis of hydrographic and direct current velocity measurements this study offers new data for a region where importation of central waters subpolar and subtropical modes of eastern north atlantic central water and exports of mediterranean water are strongly related to large scale dynamics in the north atlantic ocean azores current mediterranean water system the description is backed up quantitatively by the results of a box inverse model which was used to obtain absolute water mass transport values consistent with thermal wind equations and with conservation of volume salt and heat the contributions of water masses were determined in an extended optimum multiparameter analysis from a quasi synoptic point of view providing detail in addition to volume salt and heat transport the surface subsurface large scale current system in the region consists of the azores current 13 1 2 5 sverdrup sv 1 sv 10 6 m 3 s 1 the azores counter current 5 2 2 1 sv the portugal current 4 5 1 4 sv and the canary current 7 1 1 1 sv broadly speaking central waters are imported into the caibox region at a rate of 1 6 0 9 sv and mediterranean water is exported at a rate of 1 5 0 4 sv the downwelling of central waters west of gibraltar strait was quantified at 1 1 sv not all this volume participates in mw formation but 0 8 sv of entrained central waters of which 0 5 sv are from central waters of subpolar origin and 0 3 sv from subtropical central waters of the 4 9 sv of subtropical central waters advected by the azores current about 0 7 sv would reach the gulf of cadiz region either to take part in central water entrainment or to flow across the gibraltar strait as part of the atlantic inflow to the mediterranean sea

observed interannual variability of the atlantic meridional overturning circulation at 26 5 n the atlantic meridional overturning circulation moc plays a critical role in the climate system and is responsible for much of the heat transported by the ocean a mooring array nomianally at 26 circ n between the bahamas and the canary islands deployed in apr 2004 provides continuous measurements of the strength and variability of this circulation with seven full years of measurements we now examine the interannual variability of the moc while earlier results highlighted substantial seasonal and shorter timescale variability there had not been significant interannual variability the mean moc from 1 apr 2004 to the 31 march 2009 was 18 5 sv with the annual means having a standard deviation of only 1 0 sv from 1 april 2009 to 31 march 2010 the annually averaged moc strength was just 12 8 sv representing a 30 decline this downturn persisted from early 2009 to mid 2010 we show that the cause of the decline was not only an anomalous wind driven event from dec 2009 mar 2010 but also a strengthening of the geostrophic flow in particular the southward flow in the top 1100 m intensified while the deep southward return transport particularly in the deepest layer from 3000 5000 m weakened this rebalancing of the transport from the deep overturning to the upper gyre has implications for the heat transported by the atlantic

lunar iron and titanium abundance algorithms based on final processing of clementine ultraviolet visible images the clementine mission to the moon returned global imaging data collected by the ultraviolet visible uvvis camera this data set is now in a final state of calibration and a five band multispectral digital image model dim of the lunar surface will soon be available to the science community we have used observations of the lunar sample return sites and stations extracted from the final dim in conjunction with compositional information for returned lunar soils to revise our previously published algorithms for the spectral determination of the feo and tio2 content of the lunar surface the algorithms successfully normalize the effects of space weathering so that composition may be determined without regard to a surface s state of maturity these algorithms permit anyone with access to the standard archived dim to construct high spatial resolution maps of feo and tio2 abundance such maps will be of great utility in a variety of lunar geologic studies

compositional analyses of small lunar pyroclastic deposits using clementine multispectral data clementine ultraviolet visible uvvis data are used to examine the compositions of 18 pyroclastic deposits 15 small three large at 13 sites on the moon compositional variations among pyroclastic deposits largely result from differing amounts of new basaltic or juvenile material and reworked local material entrained in their ejecta upon eruption characterization of pyroclastic deposit compositions allows us to understand the mechanisms of lunar explosive volcanism evidence for compositional differences between small pyroclastic deposits at a single site is observed at atlas crater at all sites compositional variation among the small pyroclastic deposits is consistent with earlier classification based on earth based spectra three compositional groups can be observed and the trend of increasing mafic absorption band strength from group 1 to group 2 to group 3 is noted as redefined here group 1 deposits include those of alphonsus west alphonsus southeast alphonsus northeast 2 atlas south cruger franklin grimaldi lavoisier oppenheimer orientale and riccioli group 1 deposits resemble lunar highlands with weak mafic bands and relatively high uv vis ratios group 2 deposits include those of alphonsus northeast 1 atlas north eastern frigoris east and west and aristarchus plateau group 2 deposits are similar to mature lunar maria with moderate mafic band depths and intermediate uv vis ratios the single group 3 deposit j herschel has a relatively strong mafic band and a low uv vis ratio and olivine is a likely juvenile component two of the deposits in these groups orientale and aristarchus are large pyroclastic deposits the third large pyroclastic deposit apollo 17 taurus littrow has a very weak mafic band and a high uv vis ratio and it does not belong to any of the compositional groups for small pyroclastic deposits the observed compositional variations indicate that highland and mare materials are also present in many large and small pyroclastic deposits and they suggest that volcanic glasses or spheres may not be dominant juvenile components in all large pyroclastic deposits

the origin of lunar concentric craters abstract lunar concentric craters are a unique class of impact craters because the interior of the craters contains a concentric ridge but their formation mechanism is unknown in order to determine the origin of concentric craters we examined multiple working hypotheses which include eight impact related and endogenic processes we analyzed data sets that originated from instruments onboard clementine kaguya and the lunar reconnaissance orbiter to characterize the morphology spatial distribution composition and absolute model ages of 114 concentric craters concentric craters contain five key properties 1 a concentric ridge 2 anomalously shallow floors 3 their occurrence is concentrated near mare margins and in mare pond regions 4 the concentric ridge composition is similar to the surrounding area and 5 concentric crater ages are eratosthenian and older these five key properties served as constraints for testing impact related and endogenic mechanisms of formation we find that most impact related hypotheses cannot explain the spatial and age distribution of concentric craters as for endogenic hypotheses we deduce that igneous intrusions are the likely mechanism that formed concentric craters because of the close relationship between concentric craters and floor fractured craters and the concentration of both features near mare highland boundaries and in mare ponds furthermore we observe that floor fractured craters are common at crater diameters 15 km whereas concentric craters are common at crater diameters 15 km produce floor fractured craters

lunar mare deposits associated with the orientale impact basin new insights into mineralogy history mode of emplacement and relation to orientale basin evolution from moon mineralogy mapper m3 data from chandrayaan 1 1 moon mineralogy mapper m3 image and spectral reflectance data are combined to analyze mare basalt units in and adjacent to the orientale multiring impact basin models are assessed for the relationships between basin formation and mare basalt emplacement mare basalt emplacement on the western nearside limb began prior to the orientale event as evidenced by the presence of cryptomaria the earliest post orientale event mare basalt emplacement occurred in the center of the basin mare orientale and postdated the formation of the orientale basin by about 60 100 ma over the next several hundred million years basalt patches were emplaced first along the base of the outer rook ring lacus veris and then along the base of the cordillera ring lacus autumni with some overlap in ages the latest basalt patches are as young as some of the youngest basalt deposits on the lunar nearside m3 data show several previously undetected mare patches on the southwestern margins of the basin interior regardless the previously documented increase in mare abundance from the southwest toward the northeast is still prominent we attribute this to crustal and lithospheric trends moving from the farside to the nearside with correspondingly shallower density and thermal barriers to basaltic magma ascent and eruption toward the nearside the wide range of model ages for orientale mare deposits 3 70 1 66 ga mirrors the range of nearside mare ages indicating that the small amount of mare fill in orientale is not due to early cessation of mare emplacement but rather to limited volumes of extrusion for each phase during the entire period of nearside mare basalt volcanism this suggests that nearside and farside source regions may be similar but that other factors such as thermal and crustal thickness barriers to magma ascent and eruption may be determining the abundance of surface deposits on the limbs and farside the sequence timing and elevation of mare basalt deposits suggest that regional basin related stresses exerted control on their distribution our analysis clearly shows that orientale serves as an excellent example of the early stages of the filling of impact basins with mare basalt

temporal variability of mass transport in the canary current abstract the variability of the canary current is investigated using bimonthly expandable bathythermograph sections from gran canaria island to the african coast between november 1996 and september 1998 the geostrophic transport of the easternmost branch of the canary current is estimated by integrating the thermal wind equation using the layer of neutral density 27 3 roughly 600 m depth as the layer of no motion the yearly average geostrophic transport of this branch of the canary current is 1 8 1 4 10 9 kg s 1 southward approximately half of the transport flows through the channel between the islands of gran canaria and fuerteventura and the other half through the channel between fuerteventura and the african coast the total southward geostrophic transport shows significant seasonal variability ranging from 1 2 0 3 10 9 kg s 1 in may to 2 6 0 1 10 9 kg s 1 in january although november is the only month with considerable differences in geostrophic transport between 1996 and 1997 there is seasonal northward transport in both channels during may in the gran canaria fuerteventura channel and during november in the fuerteventura african coast channel this seasonal pattern is probably linked to autumn weakening of upwelling in the canary islands area and the offshore diversion of this flow at cape ghir

volcanic glass signatures in spectroscopic survey of newly proposed lunar pyroclastic deposits moon mineralogy mapper spectroscopic observations are used to assess the mineralogy of five sites that have recently been proposed to include lunar dark mantle deposits dmds volcanic glasses have for the first time clearly been identified at the location of three of the proposed pyroclastic deposits this is the first time that volcanic glasses have been identified at such a small scale on the lunar surface from remote sensing observations deposits at birt e schluter and walther a appear to be glassy dmds deposits at birt e and schluter show 1 morphological evidence suggesting a likely vent and 2 mineralogical evidence indicative of the presence of volcanic glasses the walther a deposits although they show no morphological evidence of vents have the spectroscopic characteristics diagnostic of volcanic glasses the deposits of the freundlich sharonov basin are separated in two areas 1 the buys ballot deposits lack mineralogical and morphological evidence and thus are found to be associated with mare volcanism not with dmds and 2 the anderson crater deposits which do not exhibit glassy dmd signatures but they appear to be associated with possible vent structures and so may be classifiable as dmds finally dark deposits near the crater kopff are found to be associated with likely mare volcanism and not associated with dmds the spectral identification of volcanic glass seen in many of the potential dmds is a strong indicator of their pyroclastic origin

large shield volcanoes on the moon 1 the volcanic style of the moon has long been understood to consist almost exclusively of flood basalts erupted from fissures along with minor pyroclastic activity large central vent shield volcanoes that characterize basaltic volcanism on the other terrestrial planets appeared to be absent small few kilometers diameter central vent constructs have long been recognized in the lunar maria and often are found clustered in fields throughout the lunar maria new global topographic data from the lola and lroc instruments on lro reveal that almost all of these volcanic complexes on the moon occur on large regional topographic rises in the lunar maria tens to hundreds of kilometers in extent and between several hundred to several thousand meters high we propose that these topographic swells are shield volcanoes and are the lunar equivalents of the large basaltic shields found on the earth venus and mars the newly recognized lunar shields are found peripheral to the large deeply flooded impact basins imbrium and serenitatis suggesting a genetic relation to those features loading of the lithosphere by these basalt filled basins may be responsible for inducing a combination of flexural and membrane stress inducing a pressure distribution on vertically oriented dikes favorable to magma ascent this condition would occur in a zone annular to the large circular loads produced by the basins where the shield volcanoes occur

meridional overturning transports at 7 5n and 24 5n in the atlantic ocean during 1992 93 and 2010 11 abstract transatlantic hydrographic sections along latitudes 7 5n and 24 5n have been repeated with about 20 years difference at the beginning of the 1990s and 2010s for each period an inverse model is applied to the closed box bound by both sections the model imposes mass conservation for individual layers defined by isoneutral surfaces and the whole water column using surface ekman transport and several transport constraints for specific ranges of longitudes and depths as a result the velocities at the reference layer for each station pair and the dianeutral velocities between layers are estimated and the horizontal velocity fields and the water heat and freshwater transports are calculated in particular we find that mass transport per stratum at 24 5n in 2011 is in good agreement with the transport estimates from the rapid watch array during both realizations the dianeutral velocities downwell from the upper north atlantic deep water unadw to the lower north atlantic deep water lnadw strata resulting in the merging of the two southward flowing strata at 24 5n into one deep southward moving stratum at 7 5n at 24 5n there is an increase in southward unadw transport between 1992 and 2011 compensated by a decrease of southward lnadw transport a descent in the upper limit of the antarctic bottom water aabw from 1992 to 2011 is also inferred the atlantic meridional overturning circulation amoc is larger in 1992 93 than in 2010 11 decreasing from 24 7 1 7 to 20 1 1 4 sv at 24 5n and from 29 2 1 7 to 16 9 1 5 sv at 7 5n much of this decrease arises because of the northward flow of antarctic intermediate water aaiw which was much more intense in 1992 93 than in 2010 11 as a consequence heat transport at 24 5n is not significantly different in 1992 1 4 0 1 pw and 2011 1 2 0 1 pw the estimation of heat transport at 7 5n strongly depends on the magnitude of the north brazil current over the american continental platform the freshwater flux into the box bounded by the two transoceanic sections decreases significantly from 1992 93 0 45 0 05 sv to 2010 11 0 36 0 3 sv meaning a decrease in net evaporation over this same area

meddies and decadal changes at the azores front from 1980 to 2000 twenty years of time series observations from the deep sea mooring kiel276 are used to obtain information on the frequency and propagation of meddies mediterranean water eddies on long term changes in flow properties and on a possible relation to the north atlantic oscillation the mooring was set at the nominal position 33 n 22 w at a water depth of more than 5200 m in the northern canary basin it is located near the southern boundary of the azores current ac which is part of the north atlantic subtropical gyre and also in the large scale mediterranean water mw tongue originating from the strait of gibraltar the amplitudes of time varying vertical quasi geostrophic modes and the correlation of current and temperature changes at levels in the mw and the north atlantic central water above are used to identify meddies a total of 10 meddies passed the mooring during the period 1980 2000 half of the events can be related to earlier observations directional changes in meddy related velocities are used to estimate speeds and directions of meddy propagation directions of propagation are very homogeneous with all the 10 meddies observed propagating with a southward velocity component within a sector of 90 and typical speeds are 2 3 cm s meddy occurrence was uneven in time with six meddies found during the first four years and only four meddies during the remaining 16 years decadal changes show the annual mean and the fluctuating kinetic energy levels at the site changing from lower values in the 1980s to high values in the 1990s this change appears to be correlated with variations in the north atlantic oscillation nao index with a delay in oceanic response of about 3 years a conceptual model of ac meanders is used to identify meander signals in the upper layer time series the ac axis appears to be closer to the site during the 1990s than during the preceding decade and indicates a southward or southwestward displacement of the ac with increasingly positive values of the nao index meddy frequency is lower when the ac gets closer from the north a reduction in meddy occurrence in the region just south of the ac is possibly caused by the shear induced blocking of some meddies crossing the front from the north

remote sensing of lunar pyroclastic mantling deposits abstract mantling deposits on the moon are considered to be pyroclastic units emplaced on the lunar surface as a result of explosive fire fountaining these pyroclastic units are characterized as having low albedos having smooth fine textured surfaces and consisting in part of homogeneous febearing volcanic glass and partially crystallized spheres mantling units exhibit low returns on depolarized 3 8 cm radar maps indicating an absence of surface scatterers in the 1 to 50 cm size range a number of reflectance spectra from several regional pyroclastic deposits are presented for the first time these data support a previous interpretation that mantling units have a unique spectral signature which is indicative of the presence of a significant fe bearing volcanic glass component the rima bode region is discussed as an example of an area in which several types of remote sensing data including 3 8 cm radar spectral reflectance and multispectral vidicon data were used to reconstruct the geologic events surrounding the emplacement of a regional pyroclastic mantling deposit the recognition of numerous varieties of volcanic glass samples especially relatively high albedo e g green yellow glasses suggests the existence of additional unrecognized mantling deposits with albedos higher than those studied to date on the basis of the remote sensing data summarized and presented five new areas have been identified which may represent higher albedo regional pyroclastic deposits

the upper oceanic response to overflows a mechanism for the azores current abstract the oceanic response to overflows is explored using a two layer isopycnal model overflows enter the open ocean as dense gravity currents that flow along and down the continental slope while descending the slope overflows typically double their volume transport by entraining upper oceanic water the upper oceanic layer must balance this loss of mass and the resulting convergent flow produces significant vortex stretching overflows thus represent an intense and localized mass and vorticity forcing for the upper ocean in this study simulations show that the upper ocean responds to the overflow induced forcing by establishing topographic plumes that are aligned more or less along isobaths and that have a transport that is typically a few times larger than that of the overflows for the topographic plume driven by the mediterranean overflow the occurrence of eddies near cape st vincent portugal allows the topographic plume to flow across isobaths the modeled topographic plume circu

nine years of mass transport data in the eastern boundary of the north atlantic subtropical gyre 1 one of the longest current meter time series in the lanzarote passage in the eastern boundary of the north atlantic subtropical gyre has been used to determine and quantify the 9 year mean transport the inter annual and seasonal mass transport variability for the three water masses present in the area results show north atlantic central water nacw flowing southward in the upper levels with a mean mass transport of 0 81 1 48 sv antarctic intermediate water aaiw flowing northward at intermediate levels with a mean transport of 0 09 0 57 sv and mediterranean water mw flowing southward in the deep part of the passage with a mean transport of 0 05 0 17 sv harmonic and wavelet analysis show the presence of a seasonal pattern in the passage for the three water masses a maximum southward transport in winter and spring has been observed for the nacw followed by a minimum in summer and fall near zero values during winter and spring are found for aaiw with a maximum northward value in summer and a negative value in fall when this water mass reverses its flow mw has a similar seasonal pattern to nacw the vertical structure in the lanzarote passage can be approximated by four significant oscillatory modes which cumulatively explain 86 4 of the variance the strong transport fluctuation found at the seasonal and inter annual timescales demonstrates that the eastern boundary current transport has a strong impact on meridional overturning estimates thus indicating that to understand meridional overturning circulation variability these transport estimates at the eastern atlantic margin are necessary

the mineralogy of late stage lunar volcanism as observed by the moon mineralogy mapper on chandrayaan 1 1 the last major phases of lunar volcanism produced spectrally unique high titanium basalts on the western nearside of the moon the moon mineralogy mapper m3 on chandrayaan 1 has provided detailed measurements of these basalts at spatial and spectral resolutions necessary for mineralogical interpretation and mapping of distinct compositional units the m3 imaging spectrometer acquired data in 85 spectral bands from 430 to 3000 nm at 140 to 280 m pixel in its global mapping mode during the first half of 2009 reflectance data of several key sites in the western maria were also acquired at higher spatial and spectral resolutions using m3 s target mode prior to the end of the chandrayaan 1 mission these new observations confirm that both fresh craters and mare soils within the western high ti basalts display strong 1 m and weak 2 m absorptions consistent with olivine rich basaltic compositions the inferred abundance of olivine is observed to correlate with stratigraphic sequence across different mare regions and absolute ages the apparent stratigraphic evolution and fe rich compositions of these basalts as a whole suggest an origin from evolved residual melts rather than through the assimilation of more primitive olivine rich sources mare deposits with spectral properties similar to these late stage high ti basalts appear to be very limited outside the procellarum imbrium region of the moon and where present appear to occur as small areas of late stage regional volcanism detailed analyses of these new data and supporting measurements are in progress to provide further constraints on the mineralogy olivine abundance and compositions of these final products of lunar volcanism and the nature and evolution of their source regions

iron abundances on the lunar surface as measured by the lunar prospector gamma ray and neutron spectrometers i global measurements of iron abundances on the lunar surface are presented using data from the lunar prospector lp gamma ray spectrometer grs and neutron spectrometer ns in this study we derive relative iron abundances from the low altitude high spatial resolution 45 km 2 lp data using the 7 6 mev neutron capture gamma ray doublet as part of the lp grs analysis we demonstrate the importance of accounting for variations in neutron number density across the lunar surface by measuring neutron fluxes using lp ns data in a first step of comparing the lp grs data with previously published iron abundances inferred from clementine spectral reflectance csr data we show that the existing csr feo data are nonlinear with respect to the lp relative iron abundances we use the lp data to linearize the relationship between the csr and the relative iron values then recalibrate the csr data to iron abundance using returned soil abundances we then correlate the csr data except for major anomalies with the lp relative iron measurements to convert the lp data to absolute iron abundances when we compare the lp grs and revised csr data sets we find a very good correspondence there are two locations mare tranquillitatis and south pole aitken spa basin that show major discrepancies suggesting that the csr data are locally overestimating iron abundances in both these regions the discrepancies identified by the lp grs csr comparison are possibly explained by mineralogical differences that are not accounted for in the csr to feo calibration in regards to our understanding of the moon the lp data have found the following i there exist large expanses of mare basalt in the western mare regions that have very high iron abundances 22 23 wt feo that are underrepresented but not absent from the returned sample collection and are highly unusual for mare soils which typically contain a significant amount of highlands contamination 2 the low iron abundances in the lunar highlands 5 feo wt are consistent with a previous analysis using thermal and epithermal neutrons and with the idea that the lunar crust formed by a relatively simple magma ocean process 3 the comparison of lp and csr derived iron abundances suggests that the material within spa basin is similar to a norite type rock without an enriched mantle feo signature 4 a comparison of lp and csr data at tycho crater shows a large discrepancy such that the csr data show moderate iron abundances of 8 9 wt feo while the lp data show very low iron abundances of 3 4 wt feo this discrepancy cannot yet be easily explained by any known process