nonlinear simulations of jupiter s 5 micron hot spots large scale nonlinear simulations of jupiter s 5 micron hot spots produce long lived coherent structures that cause subsidence in local regions explaining the low cloudiness and the dryness measured by the galileo probe inside a hot spot like observed hot spots the simulated coherent structures are equatorially confined have periodic spacing propagate west relative to the flow are generally confined to one hemisphere and have an anticyclonic gyre on their equatorward side the southern edge of the simulated hot spots develops vertical shear of up to 70 meters per second in the eastward wind which can explain the results of the galileo probe doppler wind experiment

purple haze combined geochemical and pb sr isotope constraints on colourants in celtic glass abstract the composition of 2977 late prehistoric glass objects was investigated to derive information on the nature of the colourants used 2673 late iron age celtic la tene bracelet fragments from the netherlands and austria and 51 early iron age beads from the netherlands were analysed hand held xrf analyses demonstrated that all glass objects were of the soda silica lime type which has a presumed origin in the eastern mediterranean copper was used as colourant in the form of copper filings in most of the early iron age glass beads to give recycled glass a blue green colour the vast majority 98 of the translucent iron age glass was coloured using cobalt blue manganese purple colourless antimony colourless and iron green manganese however was added to all glass contributing additional amounts of elements like copper cobalt and iron opaque decorations were produced using antimony or a combination of tin and lead ree analyses on a selection of representative objects indicate that the manganese ores in translucent glass are of hydrogenetic diagenetic early iron age or hydrothermally influenced diagenetic late iron age types strontium isotope ratios show mixing between a calcite related seawater source 0 709 and manganese ores with isotope ratios of 0 70766 lead isotope ratios are dominated by colourant derived pb the isotope ratios of the manganese used to produce translucent glass and lead used for opaque glass decorations fall in the same range the most likely general provenance of both lies on lavrion or the western cycladic islands although an origin in the central taurus or the sinai mountains cannot be excluded the conclusion is that manganese ore used for colourants contributes significantly to the ree concentration in the glass including nd as well as to sr and pb this needs to be taken into account when using concentrations or isotope ratios of these elements for provenancing other raw materials like sand and calcium carbonate this appears to be the case for all antique soda lime silica glass

polar lightning and decadal scale cloud variability on jupiter although lightning has been seen on other planets including jupiter polar lightning has been known only on earth optical observations from the new horizons spacecraft have identified lightning at high latitudes above jupiter up to 80 n and 74 s lightning rates and optical powers were similar at each pole and the mean optical flux is comparable to that at nonpolar latitudes which is consistent with the notion that internal heat is the main driver of convection both near infrared and ground based 5 micrometer thermal imagery reveal that cloud cover has thinned substantially since the 2000 cassini flyby particularly in the turbulent wake of the great red spot and in the southern half of the equatorial region demonstrating that vertical dynamical processes are time varying on seasonal scales at mid and low latitudes on jupiter

provenance of polychrome and colourless 8th 4th century bc glass from pieria greece a chemical and isotopic approach abstract glass objects from pydna and methoni in modern day greece dated to the eighth to fourth century bc were chemically investigated the combined use of multiple analytical techniques allowed the elemental and isotopic characterization of these polychrome and colourless glass artefacts in order to examine their provenance all fragments were found to be soda lime silica natron based glass produced from a rather pure silica rich sand containing sea shells and mixed with natron possibly coming from more than one source based on the strontium and neodymium isotopic signatures most glass artefacts likely derive from a syro palestinian production site although the exact location is unknown also the oxygen isotopic signature of most of the samples suggests the manufacturing of the artefacts from raw materials with a primary origin along the syro palestinian coast nevertheless the use of particular raw materials cannot be excluded for some artefacts as some samples show enriched 18 o values pointing to a different glassmaking tradition

the mode of formation of chromium poor megacryst suites from kimberlites the nature of magma bodies associated with the formation of cr poor megacryst suites included in kimberlites is considered with particular regard to the possibility of a virtually isobaric body containing crystals at widely varying temperatures a model is proposed in which a complex of magma sheets and other apophyses exists in a temperature gradient thereby allowing the simultaneous existence of different states of magma differentiation and crystallization

spatial distribution of visible lightning on jupiter spacecraft observations have provided evidence for the existence of lightning on venus1 3 jupiter4 5 saturn6 7 and uranus8 little is known however about the global distribution of lightning on these planets because of the limited spatial resolution and areal coverage of these previous detections which have principally involved radio frequency measurements two long exposure images obtained by the voyager 1 spacecraft of a small area on the nightside of jupiter have provided the only previously studied imaging observations of lightning on another planet9 10 here we present an analysis of all suitable voyager images of jupiter and evaluate the horizontal spatial distribution of visible lightning over most of one hemisphere essentially all the detectable activity is confined to very narrow latitude bands at 13 5 n and 49 n the active regions at 49 n are the brightest most numerous and periodic in longitude activity at this latitude is long lived and is most likely associated with moist convective regions deep in jupiter s atmosphere the longitudinal periodicity of the lightning storms may represent the effects of a planetary scale atmospheric wave trapped at the depth of the moist convection11 12

the galileo probe doppler wind experiment measurement of the deep zonal winds on jupiter during its descent into the upper atmosphere of jupiter the galileo probe transmitted data to the orbiter for 57 5 min accurate measurements of the probe radio frequency driven by an ultrastable oscillator allowed an accurate time history of the probe motions to be reconstructed removal from the probe radio frequency profile of known doppler contributions including the orbiter trajectory the probe descent velocity and the rotation of jupiter left a measurable frequency residual due to jupiter s zonal winds and microdynamical motion of the probe from spin swing under the parachute atmospheric turbulence and aerodynamic buffeting from the assumption of the dominance of the zonal horizontal winds the frequency residuals were inverted and resulted in the first in situ measurements of the vertical profile of jupiter s deep zonal winds a number of error sources with the capability of corrupting the frequency measurements or the interpretation of the frequency residuals were considered using reasonable assumptions and calibrations from prelaunch and in flight testing it is found that beneath the cloud tops about 700 mbar the winds are prograde and rise rapidly to 170 m s at 4 bars beyond 4 bars to the depth at which the link with the probe was lost nearly 21 bars the winds remain constant and strong corrections for the high temperatures encountered by the probe have recently been completed and provide no evidence of diminishing or strengthening of the zonal wind profile in the deeper regions explored by the galileo probe

thermal structure of jupiter s atmosphere near the edge of a 5 μm hot spot in the north equatorial belt thermal structure of the atmosphere of jupiter was measured from 1029 km above to 133 km below the 1 bar level during entry and descent of the galileo probe the data confirm the hot exosphere observed by voyager 900 k at 1 nanobar the deep atmosphere which reached 429 k at 22 bars was close to dry adiabatic from 6 to 16 bars within an uncertainty 0 1 k km the upper atmosphere was dominated by gravity waves from the tropopause to the exosphere shorter waves were fully absorbed below 300 km while longer wave amplitudes first grew then were damped at the higher altitudes a remarkably deep isothermal layer was found in the stratosphere from 90 to 290 km with t 160 k just above the tropopause at 260 mbar there was a second isothermal region 25 km deep with t 112 k between 10 and 1000 mbar the data substantially agree with voyager radio occultations the voyager 1 equatorial occultation was similar in detail to the present sounding through the tropopause region the voyager iris average thermal structure in the north equatorial belt neb approximates a smoothed fit to the present data between 0 03 and 400 mbar differences are partly a result of large differences in vertical resolution but may also reflect differences between a hot spot and the average neb at 15 4 bars probe descent velocities derived from the data are consistently unsteady suggesting the presence of large scale turbulence or gravity waves however there was no evidence of turbulent temperature fluctuations 0 12 k a conspicuous pause in the rate of decrease of descent velocity between 1 1 and 1 35 bars where a disturbance was also detected by the two radio doppler experiments implies strong vertical flow in the cloud seen by the probe nephelometer at p 0 6 bar measured temperatures were 3 k warmer than the dry adiabat possible evidence of radiative warming this could be associated with a tenuous cloud detected by the probe nephelometer above the 0 51 bar level for an ammonia cloud to form at this level the required abundance is 0 20 solar

a detection of water ice on jupiter with voyager iris abstract possible water ice spectral signatures have been detected on jupiter using voyager infrared interferometer spectrometer and radiometer iris spectra taken near closest approach of the voyager 1 and 2 missions comparison with simultaneous imaging data shows that these iris footprints approximately correspond to locations on the planet where deep convection is suspected of the sample of 7500 spectra approximately 1 show a water ice absorption feature near 44 m the infrared optical depths of the absorption features between 0 18 and 0 44 indicate that large amounts of ice particles need not be present to produce the observed spectral signature the water ice clouds would have visible optical depths on the order of unity and would not be distinguishable above a thick ammonia cloud deck which can have much larger visible optical depths these thin clouds yield about 1 precipitable micrometer of water comparable to martian tharsis ridge clouds

motions in jovian hot spot plume regions using voyager images abstract we have measured the motions and wind velocity vectors in six jovian hot spot plume areas latitudes 0 to 12 using high resolution voyager 1 and 2 images separated by one jovian rotation 10 hr rapid changes in cloud forms take place in a few hours at scales from 100 to 2000 km no large scale organized motions e g diagonal convergence along the plume tails toward hot spots or circulation patterns such as those recently reported using galileo images separated by 1 hr have been found we show that particle evaporation and cloud element mixing in the upper ammonia cloud could be fast enough to dissipate the small cloud elements such as those used as tracers by the galileo ssi team in less than 10 hr

saturn s visible lightning its radio emissions and the structure of the 2009 2011 lightning storms visible lightning on saturn was first detected by the cassini camera in 2009 at 35 south latitude we report more lightning observations at 35 south later in 2009 and lightning in the 2010 2011 giant lightning storm at 35 north the 2009 lightning is detected on the night side of saturn in a broadband clear filter the 2011 lightning is detected on the day side in blue wavelengths only in other wavelengths the 2011 images lacked sensitivity to detect lightning which leaves the lightning spectrum unknown the prominent clouds at the west edge or the head of the 2010 2011 storm periodically spawn large anticyclones which drift off to the east with a longitude spacing of 10 15 10 000 km the wavy boundary of the storm s envelope drifts with the anticyclones the relative vorticity of the anticyclones ranges up to f 3 where f is the planetary vorticity the lightning occurs in the diagonal gaps between the large anticyclones the vorticity of the gaps is cyclonic and the atmosphere there is clear down to level of the deep clouds in these respects the diagonal gaps resemble the jovian belts which are the principal sites of jovian lightning the size of the flash illuminated cloud tops is similar to previous detections with diameter 200 km this suggests that all lightning on saturn is generated at similar depths 125 250 km below the cloud tops probably in the water clouds optical energies of individual flashes for both southern storms and the giant storm range up to 8 10 9 j which is larger than the previous 2009 equinox estimate of 1 7 10 9 j cassini radio measurements at 1 16 mhz suggest that assuming lightning radio emissions range up to 10 ghz lightning radio energies are of the same order of magnitude as the optical energies southern storms flash at a rate 1 2 per minute the 2011 storm flashes hundreds of times more often 5 times per second and produces 10 10 w of optical power based on this power the storm s total convective power is of the order 10 17 w which is uncertain by at least an order of magnitude and probably is underestimated this power is similar to saturn s global internal power radiated to space it suggests that storms like the 2010 2011 giant storm are important players in saturn s cooling and thermal evolution

nickeliferous sulfides in xenoliths olivine megacrysts and basaltic glass the composition of olivine and nickeliferous sulfide inclusions from a selection of mafic and ultramafre rocks xenoliths and megacrysts including picritic basalts from kilauea volcano hawaii kimberlite from fayette county pennsylvania and megacrysts from mount shasta california are compared with the mean experimental value of the distribution coefficient for ni fe exchange kd3 32 only nine of the forty five olivipe bulk sulfide pairs investigated have compositions consistent with equilibration at high temperature yielding calculated kd3 values in the range 22 to 41 the remaining pairs have calculated kd3 values which range from 0 to 19 bulk sulfides in disequilibrated assem blages are consistently depleted in nickel and within both indivudual associations and individual petrographic sections they exhibit a wide variation in nis content the bulk copper contents of olivine and groundmass hosted sulfides from kilauea volcano range from 0 5 to 43 at and samples from the kilauea iki lava lake are more fe and cu rich and generally have lower kd3 values than those from the eruption itself as with magmatic ni cu sulfide deposits most nickeliferous sulfide inclusions in mantle related rocks and xenoliths and in volcanic rocks do not have pristine early magmatic bulk compositions and it would seem to be premature to attribute these sulfides solely to either a mantle or an early magnatic origin

neptune s global circulation deduced from multi wavelength observations abstract we observed neptune between june and october 2003 at near and mid infrared wavelengths with the 10 m w m keck ii and i telescopes respectively and at radio wavelengths with the very large array images were obtained at near infrared wavelengths with nirc2 coupled to the adaptive optics system in both broad and narrow band filters between 1 2 and 2 2 m in the mid infrared we imaged neptune at wavelengths between 8 and 22 m and obtained slit resolved spectra at 8 13 m and 18 22 m at radio wavelengths we mapped the planet in discrete filters between 0 7 and 6 cm we analyzed each dataset separately with a radiative transfer program that is optimized for that particular wavelength regime at southern midlatitudes the atmosphere appears to be cooler at mid infrared wavelengths than anywhere else on the planet we interpret this to be caused by adiabatic cooling due to air rising at midlatitudes at all longitudes from the upper troposphere up to 0 1 mbar levels at near infrared wavelengths we find two distinct cloud layers at these latitudes a relatively deep layer of clouds presumably methane in the troposphere at pressure levels p 300 600 mbar which we suggest to be caused by the large scale upwelling and its accompanying adiabatic cooling and condensation of methane and a higher spatially intermittent layer of clouds in the stratosphere at 20 30 mbar the latitudes of these high clouds encompass an anticyclonic band of zonal flow which suggests that they may be due to strong but localized vertical upwellings associated with local anticyclones rather than plumes in convective i e cyclonic storms clouds at northern midlatitudes are located at the highest altitudes in the atmosphere near 10 mbar neptune s south pole is considerably enhanced in brightness at both mid infrared and radio wavelengths i e from 0 1 mbar levels in the stratosphere down to tens of bars in the troposphere we interpret this to be due to subsiding motions from the stratosphere all the way down to the deep troposphere the enhanced brightness observed at mid infrared wavelengths is interpreted to be due to adiabatic heating by compression in the stratosphere and the enhanced brightness temperature at radio wavelengths reveals that the subsiding air over the pole is very dry the relative humidity of h 2 s over the pole is only 5 at altitudes above the nh 4 sh cloud at 40 bar the low humidity region extends from the south pole down to latitudes of 66 s this is near the same latitudes as the south polar prograde jet signifying the boundary of the polar vortex we suggest that the south polar features spfs at latitudes of 60 70 are convective storms produced by baroclinic instabilities expected to be produced at latitudes near the south polar prograde jet taken together our data suggest a global circulation pattern where air is rising above southern and northern midlatitudes from the troposphere up well into the stratosphere and subsidence of dry air over the pole and equator from the stratosphere down into the troposphere we suggest that this pattern extends all the way from 0 1 mbar down to pressures of 40 bar

sasanian glass from veh ardasīr investigated by strontium and neodymium isotopic analysis abstract a collection of 31 glass fragments dated to the 3rd to 7th century ad and excavated in veh ardas r modern iraq were analysed for their sr and nd isotopic compositions with the aim of deepening our knowledge on glass circulating within central mesopotamia during sasanian times and to highlight the merits of isotope ratios for the definition of the production scenery based on the elemental composition of the samples two groups related to the exploitation of different plant ashes were previously distinguished and also a change in the silica source in the course of the 4th century ad emerged the determination of isotopic distributions of sr and nd offers a deeper insight the 87 sr 86 sr isotope ratio together with the sr elemental concentration confirms this use of different plant ashes and permits one to distinguish distinct glass batches although the isotopic sr signature does not allow us to highlight evidences of different provenances for the samples of different composition moreover the 143 nd 144 nd isotope ratio suggests the use of sands belonging to a common geological area and also allows the identification of a set of samples that were possibly produced exploiting a further different sand source as a whole sr and nd isotope ratio values for the samples considered i e 87 sr 86 sr 0 70833 to 0 70916 and nd 8 69 to 4 98 differ from the published isotopic data on middle eastern glass samples and can therefore define a characteristic sr nd signature for plant ash sasanian glass excavated in veh ardas r

a study of the possibility of sprites in the atmospheres of other planets 1 sprites are a spectacular type of transient luminous events which occur above thunderstorms immediately after lightning they have shapes of giant jellyfish carrots or columns and last tens of milliseconds in earth s atmosphere sprites mostly emit in red and blue wavelengths from excited n2 and n2 and span a vertical range between 50 and 90 km above the surface the emission spectra morphology and occurrence heights of sprites reflect the properties of the planetary atmosphere they inhabit and are related to the intensity of the initiating parent lightning this paper presents results of theoretical calculations of the expected occurrence heights of sprites above lightning discharges in the co2 atmosphere of venus the n2 atmosphere of titan and the h2 he atmosphere of jupiter the expected emission features are presented and the potential of detecting sprites in planetary atmospheres by orbiting spacecraft is discussed

a three dimensional model of moist convection for the giant planets the jupiter case abstract we present a three dimensional cloud model designed for the study of formation and evolution of moist convective storms on the giant planets this is a finite difference model that solves the dynamic and thermodynamic equations forward in time under the anelastic approximation including microphysics in a parameterized form three dimensional modeling is needed to include the dynamical effects of the vertical and meridional ambient wind shears and the coriolis force on the storm onset and evolution the model is designed to run on the four giant planets to compare how moist convection operates in each case in this paper we present the results for jupiter water ammonia storms under a variety of conditions several improvements in the mathematical formulation and in the numerical methods and an update of the input values e g the thermal profile and gas abundances with respect to previous models have been incorporated we show that under the appropriate relative humidity conditions and particulate precipitation it is possible to create visible storms even with a small deep water abundance of 0 2 times the solar value the effect of the vertical wind shear is important as it is on earth in controlling the structure of the cloud its growing ratio and the local wind field but it has a small influence on the upper level reached by the storm the distribution of the convective cells created in the presence of a vertical wind shear resembles the pattern of mesoscale storms recently observed by galileo

convective storms and atmospheric vertical structure in uranus and neptune the ice giants uranus and neptune have hydrogen based atmospheres with several constituents that condense in their cold upper atmospheres a small number of bright cloud systems observed in both planets are good candidates for moist convective storms but their observed properties size temporal scales and cycles of activity differ from moist convective storms in the gas giants these clouds and storms are possibly due to methane condensation and observations also suggest deeper clouds of hydrogen sulfide h2s at depths of a few bars even deeper thermochemical models predict clouds of ammonia hydrosulfide nh4sh and water at pressures of tens to hundreds of bars forming extended deep weather layers because of hydrogen s low molecular weight and the high abundance of volatiles their condensation imposes a strongly stabilizing vertical gradient of molecular weight larger than the equivalent one in jupiter and saturn the resulting inhibition of vertical motions should lead to a moist convective regime that differs significantly from the one occurring on nitrogen based atmospheres like those of earth or titan as a consequence the thermal structure of the deep atmospheres of uranus and neptune is not well understood similar processes might occur at the deep water cloud of jupiter in saturn but the ice giants offer the possibility to study these physical aspects in the upper methane cloud layer a combination of orbital and in situ data will be required to understand convection and its role in atmospheric dynamics in the ice giants and by extension in hydrogen atmospheres including jupiter saturn and giant exoplanets this article is part of a discussion meeting issue future exploration of ice giant systems

the structure and temporal stability of jupiter s zonal winds a study of the north tropical region abstract this paper investigates possible long term zonal wind variations using voyager 1979 hubble space telescope hst 1995 1997 1998 and galileo orbiter 1997 data that has all been processed and analyzed in the same manner for consistency previous attempts to measure the zonal wind profile in voyager data had yielded inconsistent results for the maximum eastward jet near 23 7 n latitude from different studies a p ingersoll et al 1979 nature 280 773 775 ibid 1981 j geophys res 86 8733 8743 t maxworthy 1984 planet space sci 32 1053 1058 s limaye 1986 icarus 65 335 352 this paper compares previous measurements and includes new independent analysis to conclude that the correct wind jet velocity at the time of voyager is close to 182 m s 1 most consistent with the reported results of maxworthy 1984 in the data sets from different epochs the overall shape of the wind profile and locations of the prograde and retrograde jets remain constant but there are amplitude changes at a few latitudes the largest velocity deviations between the voyager and the 1995 1997 hst profiles occurred in the maximum eastward jet near 23 7 n and at 6 s and 20 s planetographic latitude possible causes for an apparent zonal wind decrease were explored using galileo visible and hst near infrared data and the wind velocity change was determined to be real a very definite change in cloud structure and brightness has also occurred at 23 7 n additionally surface brightness changes seen at 6 s and 20 s also correlated with changes in wind speed hst wfpc2 data obtained in 1998 showed the recovery of the 23 7 n region to a voyager like appearance and an increase in wind velocity to the voyager value

life cycles of spots on jupiter from cassini images using the sequence of 70 day continuum band 751 nm images from the cassini imaging science system iss we record over 500 compact oval spots and study their relation to the large scale motions the 100 spots whose vorticity could be measured the large spots in most cases were all anticyclonic we exclude cyclonic features chaotic regions because they do not have a compact oval shape but we do record their interactions with spots we distinguish probable convective storms from other spots because they appear suddenly grow rapidly and are much brighter than their surroundings the distribution of lifetimes for spots that appeared and disappeared during the 70 day period follows a decaying exponential with time constant mean lifetime of 3 5 days for probable convective storms and 16 8 days for all other spots extrapolating the exponential beyond 70 days seriously underestimates the number of spots that existed for the entire 70 day period this and other evidences size shape distribution in latitude suggest that these long lived spots with lifetime larger than 70 days are from a separate population the zonal wind profile obtained manually by tracking individual features this study agrees with that obtained automatically by correlating brightness variations in narrow latitude bands porco et al 2003 some westward jets have developed more curvature and some have developed less curvature since voyager times but the number of westward jets that violate the barotropic stability criterion is about the same in the northern hemisphere the number of spots is greatest at the latitudes of the westward jets which are the most unstable regions according to the barotropic stability criterion during the 70 day observation period the great red spot grs absorbed nine westward moving spots that originated in the south equatorial belt seb where most of the probable convective storms originate although the probable convective storms do not directly transform themselves into westward moving spots their common origin in the seb suggests that moist convection and the westward jet compose a system that has maintained the grs over its long lifetime

observations and numerical modelling of a convective disturbance in a large scale cyclone in jupiter s south temperate belt abstract moist convective storms in jupiter develop frequently and can trigger atmospheric activity of different scales from localized storms to planetary scale disturbances including convective activity confined inside a larger meteorological system in february 2018 a series of convective storms erupted in jupiter s south temperate belt stb planetocentric latitudes from 23 to 29 5 this occurred inside an elongated cyclonic region known popularly as the stb ghost close to the large anticyclone oval ba resulting in the clouds from the storms being confined to the cyclone the initial storms lasted only a few days but they generated abundant enduring turbulence they also produced dark features possibly partially devoid of clouds that circulated around the cyclone over the first week the subsequent activity developed over months and resulted in two main structures one of them closely interacting with oval ba and the other one being expelled to the west here we present a study of this meteorological activity based on daily observations provided by the amateur community complemented by observations obtained from planetcam upv ehu at calar alto observatory the hubble space telescope and by junocam on the juno spacecraft we also perform numerical simulations with the epic general circulation model to reproduce the phenomenology observed the successful simulations require a complex interplay between the ghost the convective eruptions and oval and they demonstrate that water moist convection was the source of the initial storms a simple scale comparison with other moist convective storms that can be observed in the planet in visible and methane absorption band images strongly suggests that most of these storms are powered by water condensation instead of ammonia

a comparative study of jovian cyclonic features from a six year 1994 2000 survey abstract this work presents a six year study aimed at characterizing the morphology and properties of the atmospheric features present in jovian cyclonic regions it complements our previous analysis for the same period on the anticyclonic vortices morales juberias et al 2002 icarus 157 76 90 the main difference between cyclonic and anticyclonic regions in jupiter is that a variety of organized morphologies are present in the cyclonic areas although they can be grouped consistently into five different types filamentary turbulence related to the highest speed jets organized folded filamentary regions elongated areas with contours closed by a ribbon like feature discrete closed brown cyclones barges and peculiar transient structures such as short wave trains and cyclonic cells we present data on their color contrast size aspect ratio distribution lifetimes relation to the jet system and to the anticyclones and motions global and internal to the features most cyclonic features show a rapid evolution compared to the anticyclones and tend to be dispersed zonally although some survive for a few years we used the barges that are the most representative long lived and extended type of cyclonic features to show that there exists a linear relationship between their relative velocity and the mean zonal flow speed similar to that found in our previous work on the anticyclones there is also some evidence that the drift rate of barges is related to the planetary minus flow vorticity gradient

jupiter new estimates of the mean zonal flow at the cloud level abstract previous estimates of the mean zonal flow on jupiter from voyager images by ingersoll et al a p ingersoll r f beebe j l mitchell g w garneau g m yagi and j p mueller 1981 j geophys res 86 8733 8743 and by limaye et al s s limaye h e revercomb l a sromovsky r j krauss v e suomi s a collins and c c avis 1982 j atmos sci 39 1413 1432 showed good agreement in the locations of the easterly and westerly jets but differed somewhat in magnitude recent measurements of the high speed jet located near 24 north plane topographic latitude by t maxworthy 1984 planet space sci 32 1053 1058 from high spatial and temporal resolution voyager images indicate that both ingersoll et al and limaye et al underestimated the magnitude of the jet by more than 30 40 msec 1 in an attempt to examine the differences in the magnitude of the jovian jets determined from voyager 1 and 2 images a new approach to determine the zonal mean east west component of motion was investigated the new technique based on simple digital pattern matching approach and applied on pairs of mapped images cylindrical mosaics yields a profile of the mean zonal component that reproduces the exact locations of the easterly and westerly jets between 60 latitude not only do the jet magnitudes but also the wings of the jets agree remarkably well from mosaic pair to pair further the latitudinal resolution is five midlatitudes to eight times equatorial greater than previous results results have been obtained for all of the voyager 1 and 2 cylindrical mosaics the correlation coefficient between voyager 1 and voyager 2 average mean zonal flow between 60 latitude determined from violet filter mosaics is 0 998 a slight latitude offset possibly due to navigation errors is detectable 0 2 latitude average in the voyager 1 data independent cloud motion measurements in two high resolution image pairs orange and violet acquired from voyager 1 cameras agree well with the average mean zonal flow for the fastest jovian jet at 23 8 n latitude comparison with maxworthy s 1984 results suggests longitudinal variations in cloud motions approaching about 20 msec 1 in particular the jet magnitude is about 163 7 rms msec 1 which compares well with 182 10 msec 1 reported by maxworthy there is excellent agreement in the location of the peak magnitude as well as its shape the time average voyager 2 mean zonal flow profile with latitude is presented in a table

the retrieval of cloud structure maps in the equatorial region of jupiter using a principal component analysis of galileo nims data abstract the cloud structure of the jovian atmosphere at pressures less than 2 bars has previously been estimated using near infrared observations such as those by both the solid state imager ssi and near infrared mapping spectrometer nims instruments on board the galileo spacecraft unfortunately complete near infrared spectra such as those measured by nims take a long time to be analyzed with multiple scattering radiative transfer models and thus it has until now been rather difficult to use these data to produce wide area cloud maps in this paper we show how principal component analysis may be employed to isolate a small number of empirical orthogonal functions eofs from spectra of jupiter made by galileo nims these eofs may be used to represent the variance of real nims spectra to a high degree of accuracy and with good noise and drop out discrimination because of this a small set of representative spectra may then be calculated using these eofs and input into a retrieval model that generates a table of fitted cloud profiles for each case this approach avoids the long times required for analyzing a large number of spectra with full multiple scattering radiative transfer models and allows us to represent the variability of the 3000 spectra contained in the observations of the north equatorial belt neb used in this study with only 75 representative spectra the cloud structures fitted to these representative spectra were interpolated for the spectra found at individual locations in the measured nims data set to produce maps of cloud opacity and mean particle size we find that the dominant opacity variation anticorrelated with 5 m brightness exists in the 1 2 bar pressure range the distribution of the cloud at 0 72 bars is mapped and found to be more zonally diffuse than the lower clouds we find at least one 2000 km sized deep convective cloud in the neb vertically extending to all the pressure levels that can be sensed by nims

isotopic evidence for the use of caucasian antimony in late bronze age glass making abstract antimony sb is considered a rare material in the archaeological record found only in unusual circumstances nevertheless antimony minerals were an important resource for several millennia used in metallurgy and to opacify or decolour glass and glazes in this way sb spread throughout the known world from the chalcolithic onward in glassmaking stibnite was the only available resource that could provide in any measure the very pure sb evident from trace element analyses of the earliest glass sb isotopic analysis has allowed late bronze age egyptian and mesopotamian glass vessels and caucasian sb metallic beads to be compared to the possible ancient ore sources the only known matches for the isotopic composition of the glass are stibnite ores from the racha lechkumi district in the caucasus present day georgia near the zopkhito au sb deposits mined from the 17th century bce conversely the sb metal beads represent several isotopic and trace element compositional groups only one of which matches the racha lechkumi stibnite sb extraction for glassmaking was likely unrelated to copper metallurgy and may have been associated with the mining of precious metals

production mixing and provenance of late bronze age mixed alkali glasses from northern italy an isotopic approach late bronze age glass in mesopotamia egypt and greece was made from silica and plant ashes around 1200 bc in europe a new glass type appears of a mixed alkali composition although the highest concentration of this glass is found at frattesina in the veneto northern italy there is no absolute proof that it was fused there from raw materials a variety of possible alkali raw materials have been suggested but there is still no certainty about its identity the chemical compositions of these mixed alkali glasses are characterised by a series of mixing lines which suggest that raw materials or glasses were mixed to address these issues we present here the first set of radiogenic isotope 87sr 86sr and 143nd 144nd results for highly coloured samples of 11th century bc raw and waste glass from frattesina together with new isotopic results for northern italian silica and plant samples although a relatively small number the isotopic results suggest that primary production of mixed alkali glass occurred in northern italy moreover it can be suggested that two of the samples were made from a mixture of different glasses with contrasting isotopic signatures one probably deriving from northern italy and the other from a non local source this indicates that there were two production centres for mixed alkali glass we have shown that frattesina glasses were made using isotopically distinct raw materials from those used to make the slightly earlier late bronze age mesopotamian and egyptian plant ash glasses even though we have tested a small number of samples the isotopic results nevertheless provide significant new evidence for these mixed alkali glasses being the first european glasses

galileo images of lightning on jupiter in october and november of 1997 the galileo solid state imager ssi detected lightning from 26 storms on the night side of jupiter more than half the surface area of the planet was surveyed the data include images of lightning against moonlit clouds illuminated by light from io and images of the same storm on the day and night sides the spatial resolution ranged from 23 to 134 km per pixel while the storms ranged in size up to 1500 km most storms were imaged more than once and they typically exhibit many flashes per minute the storms occur only in areas of cyclonic shear and near the centers of westward jets latitudes near 50 in both hemispheres are particularly active although the northern hemisphere has more lightning overall the greatest optical energy observed in a single flash was 1 6 10 10 j which is several times larger than terrestrial superbolts the average optical power per unit area is 3 10 7 w m 2 which is close to the terrestrial value the limited color information is consistent with line and continuum emission from atomic hydrogen and helium the intensity profiles of resolved lightning strikes are bell shaped with the half width at half maximum ranging from 45 to 80 km we used these widths to infer the depth of the strikes assuming that the appearance of each is the result of light scattering from a point source below the cloudtops we conclude that lightning must be occurring within or below the jovian water cloud the occurrence of lightning in regions of cyclonic shear has important implications for the dynamics of jupiter s atmosphere

propagation of unducted whistlers from their source lightning a case study 1 we analyze nightside measurements of the demeter spacecraft related to lightning activity at the 707 km altitude of demeter we observe 3 d electric and magnetic field waveforms of fractional hop whistlers at the same time the corresponding atmospherics are recorded by a very low frequency vlf ground based station located in nancay france the source lightning strokes are identified by the meteorage lightning detection network we perform multidimensional analysis of the demeter measurements and obtain detailed information on wave polarization characteristics and propagation directions this allows us for the first time to combine these measurements with ray tracing simulation in order to directly characterize how the radiation penetrates upward through the ionosphere we find that penetration into the ionosphere occurs at nearly vertical wave vector angles as was expected from coupling conditions at distances of 100 900 km from the source lightning the same distance is traveled by the simultaneously observed atmospherics to the vlf ground station the measured dispersion of fractional hop whistlers combined with the ionosonde measurements at the ebro observatory in spain allows us to derive the density profile in the topside ionosphere

prevalent lightning sferics at 600 megahertz near jupiter s poles lightning has been detected on jupiter by all visiting spacecraft through night side optical imaging and whistler lightning generated radio waves signatures1 6 jovian lightning is thought to be generated in the mixed phase liquid ice region of convective water clouds through a charge separation process between condensed liquid water and water ice particles similar to that of terrestrial cloud to cloud lightning7 9 unlike terrestrial lightning which emits broadly over the radio spectrum up to gigahertz frequencies10 11 lightning on jupiter has been detected only at kilohertz frequencies despite a search for signals in the megahertz range 12 strong ionospheric attenuation or a lightning discharge much slower than that on earth have been suggested as possible explanations for this discrepancy13 14 here we report observations of jovian lightning sferics broadband electromagnetic impulses at 600 megahertz from the microwave radiometer 15 onboard the juno spacecraft these detections imply that jovian lightning discharges are not distinct from terrestrial lightning as previously thought in the first eight orbits of juno we detected 377 lightning sferics from pole to pole we found lightning to be prevalent in the polar regions absent near the equator and most frequent in the northern hemisphere at latitudes higher than 40 degrees north because the distribution of lightning is a proxy for moist convective activity which is thought to be an important source of outward energy transport from the interior of the planet16 17 increased convection towards the poles could indicate an outward internal heat flux that is preferentially weighted towards the poles9 16 18 the distribution of moist convection is important for understanding the composition general circulation and energy transport on jupiter observations of broadband emission from lightning on jupiter at 600 megahertz show a lightning discharge mechanism similar to that of terrestrial lightning and indicate increased moist convection near jupiter s poles

isotopic investigation into the raw materials of late bronze age glass making this paper discusses sr nd sb isotopic analysis of late bronze age glass to investigate the origin and nature of the mineral raw materials used in early glass making sr nd isotopic analysis characterizes the flux and silica component of the glass raw material mixture this technique has been successfully applied to separate egyptian from mesopotamian glass signatures also identifying the use of at least two distinct flux silica mixtures in mesopotamian glass making sb isotopic analysis is presented as a novel technique to examine the raw material used to opacify the earliest glass it is demonstrated that egyptian and mesopotamian glass factories likely used an identical source of sb possibly originating from the caucasus this suggests a steady supply and long distance exchange or trade of this material during the late bronze age

galileo imaging of jupiter s atmosphere the great red spot equatorial region and white ovals during the first six orbits of the galileo spacecraft s prime mission the solid state imaging ssi system acquired multispectral image mosaics of jupiter s great red spot an equatorial belt zone boundary a 5 m hot spot similar to the galileo probe entry site and two of the classic white ovals we present mosaics of each region approximating their appearance at visible wavelengths and showing cloud height and opacity variations the local wind field is derived by tracking cloud motions between multiple observations of each region with time separations of roughly 1 and 10 hr vertical cloud structure is derived in a companion paper by banfieldet al icarus135 230 250 galileo s brief high resolution observations complement earth based and voyager studies and offer local meteorological context for the galileo probe results our results show that the dynamics of the zonal jets and large vortices have changed little since voyager with a few exceptions we detect a cyclonic current within the center of the predominantly anticyclonic great red spot the zonal velocity difference between 0 s and 6 s has increased by 20 m sec 1 we measure a strong northeast flow approaching the hot spot this flow indicates either massive horizontal convergence or the presence of a large anticyclonic vortex southeast of the hot spot the current compact arrangement of two white ovals and a cyclonic structure greatly perturbs the zonal jets in that region

a study of the stability of jovian zonal winds from hst images 1995 2000 abstract we present a five year study of the temporal stability of jupiter s zonal wind velocity profile at cloud level based on hubble space telescope images obtained from 1995 to 2000 we used the correlation of east west albedo scans in pairs of images separated by one jovian rotation to retrieve the zonal winds the resolution in the hst images ranged from 140 to 190 km pixel 1 independent measurements of the motions of individual cloud tracers were used to control the above profiles three wavelengths were used in this analysis 410 nm violet continuum 892 nm methane absorption band and 953 nm red continuum our study indicates that globally jupiter s zonal flow did not change during this five year interval and it does not depend on the observed wavelengths when comparing our mean profile with that obtained 16 years ago using voyager data we find a reasonable agreement we note however a small shift in the latitude of the jets poleward of latitude 30 probably due to image navigation uncertainties however true changes in the intensity of the jets at 24 n and 32 n are found results also indicate that the 7 s jet has remained stable since the voyager era in addition we extend in this paper our previous study of the 24 n with new data from year 2000 the new data confirm the jet s stability during the 1995 2000 period finally we present the average profile for this period including error estimation in a table that extends the latitudinal coverage of limaye s 1986 icarus 65 335 352 voyager profile up to latitudes 68 s and 77 n

cassini imaging of jupiter s atmosphere satellites and rings the cassini imaging science subsystem acquired about 26 000 images of the jupiter system as the spacecraft encountered the giant planet en route to saturn we report findings on jupiter s zonal winds convective storms low latitude upper troposphere polar stratosphere and northern aurora we also describe previously unseen emissions arising from io and europa in eclipse a giant volcanic plume over io s north pole disk resolved images of the satellite himalia circumstantial evidence for a causal relation between the satellites metis and adrastea and the main jovian ring and information on the nature of the ring particles

modeling jupiter s cloud bands and decks 2 distribution and motion of condensates abstract a simple jovian cloud scheme has been developed for the oxford planetary unified model system opus nh 3 ice nh 4 sh solid h 2 o ice and h 2 o liquid clouds have been modeled in southern hemisphere limited area simulations of jupiter we found that either three or four of the condensates existed in the model for a deep atmospheric water abundance close to solar composition an nh 3 ice deck above 0 7 bar an nh 4 sh solid deck above 2 5 bar and a h 2 o liquid deck with a base at about 7 5 bar and frozen cloud tops formed if a depleted deep water abundance is assumed however a very compact cloud structure develops where an h 2 o ice cloud forms by direct sublimation above 3 bar the condensates constitute good tracers of atmospheric motion and we have confirmed that zonal velocities determined from manual feature tracking in the modeled cloud layers agree reasonably well with the modeled zonal velocities dense and elevated clouds form over latitudes with strong atmospheric upwelling and depleted clouds exist over areas with strong downwelling in the nh 3 ice deck this leads to elevated cloud bands over the zones in the domain and thin clouds over the belts which is consistent with the observationally deduced distribution due to changes in the vertical velocity pattern in the deeper atmosphere the nh 4 sh solid and water cloud decks are more uniform this modeled cloud structure thus includes the possibility of more frequent water cloud observations in belts as this deeper deck could be more easily detected under areas with thin nh 3 ice clouds large scale vortices appeared spontaneously in the model and were characterized by elevated nh 3 ice clouds as expected from observations these eddies leave the most discernible imprint on the lighter condensate particles of the uppermost layer

a model for large scale convective storms in jupiter 1 large scale convective storms are a common phenomenon in jupiter s atmosphere they are apparent in ground based and spacecraft images and may strongly affect the dynamics of the global atmosphere as well as the energy transport in the meteorological layer in this paper we analyze the outburst of a large convective storm system core 5000 km in the south equatorial belt seb that was observed at high spatial and temporal resolution by the voyager 1 spacecraft in 1979 we use a two dimensional 2 d model to study the interaction between cloud material brought up by moist convection and the environmental wind aided by previous 3 d models of jovian storms we can draw several qualitative and quantitative conclusions the evolution of this storm can be characterized by three phases 1 onset of the perturbation well reproduced by the growth of a single cell storm 2 an expanding phase in which the number of convective cells increases to 200 with updraft velocities limited to 50 m s and 3 a relatively sudden suppression of the convective activity leading to the disruption of large structures by the environmental wind furthermore we interpret the observations of the inner bright core as a well defined anticyclonic vortex with darker cloud material preferentially left southwest of the system finally we show that 1016 w are released by such a storm over its life cycle of 12 days and that the direct formation of a large scale anticyclonic vortex after the moist convective source has been removed is prevented by the environmental wind shear

jupiter s atmospheric temperatures from voyager iris to cassini cirs abstract retrievals performed on cassini composite infrared spectrometer data obtained during the distant jupiter flyby in 2000 2001 have been used to generate global temperature maps of the planet in the troposphere and stratosphere but to higher latitudes than were shown previously by flasar et al flasar f m 39 colleagues 2004a nature 427 132 135 flasar f m 44 colleagues 2004b space sci rev 115 169 297 similar retrievals were performed on voyager 1 iris data to provide the first detailed iris map of the stratosphere and high latitudes in the troposphere thermal winds were calculated for each data set and show strong vertical shears in the zonal winds at low latitudes and meridional temperature gradients indicate the presence of circumpolar jets as well the temperatures retrieved from the two spacecraft were also compared with yearly ground based data obtained over the intervening two decades tropospheric temperatures reveal gradual changes at low latitudes with little obvious seasonal or short term variation orton et al 1994 science 265 625 631 stratospheric temperatures show much more complicated behavior over short timescales consistent with quasi quadrennial oscillations at low latitudes as suggested in prior analyses of shorter intervals of ground based data orton et al 1991 science 252 537 542 friedson a j 1999 icarus 137 34 55 a scaling analysis indicates that meridional motions mechanically forced by wave or eddy convergence play an important role in modulating the temperatures and winds in the upper troposphere and stratosphere on seasonal and shorter timescales at latitudes away from the equator the mechanical forcing can be derived simply from a temporal record of temperature and its vertical derivative ground based observations with improved vertical resolution and or long term monitoring from spacecraft are required for this purpose though the voyager and cassini data given indications that the magnitude of the forcing is very small

analysis of voyager 2 images of jovian lightning abstract voyager 2 images have been examined and found to contain bright spots due to lightning activity that is confined to two narrow latitude bands centered at 49 n and 13 5 n latitude and to a single region near 60 n latitude no lightning activity is observed in the southern hemisphere even though a large area was observed with the same sensitivity as that used for northern hemisphere observations the brightest band of lightning activity occurs at 49 n but no unusual cloud features can be associated with this activity this result is consistent with the depth of the lightning activity being 80 km below the ammonia clouds and thus not producing readily observed disturbances in the visible clouds the secondary band of lightning activity that appears at 13 5 n is restricted in longitude to the disturbed zone one of the two storms found in this tropical band is very close to the location of a bright cloud feature that extends some 3 5 in latitude if it is assumed that the deflection of this feature is caused by the westerly flow of an air parcel over a hill in the potential temperature surface located at the 5 to 10 bar level then the air parcel moving over the hill would be forced to rise sufficiently high that the free convection level would be reached this situation could be the cause of the lightning activity in this region the energy dissipation rate by lightning activity in the voyager 2 images is 3200 w km2 when attenuation by clouds is considered the energy dissipation rate is approximately 50 greater than that found in the voyager 1 images the ratio of the energy dissipated by jovian lightning to the thermal flux available to drive convection motions is found to be three decades larger than the terrestrial ratio this value is similar to the ratio for the two planets found by ingersoll 1990 for the conversion of thermal energy flux to mechanical energy

the al 2 o 3 contents of enstatite in equilibrium with garnet in the system mgo al 2 o 3 sio 2 at 15 40 kbar and 900 1 600 c forty six reversed determinations of the al2o3content of enstatite in equilibrium with garnet were made in the p t range 15 40 kbar 900 1 600 c in the mgo al2o3 sio2 system starting materials were mixtures of synthetic pyrope al free enstatite and pyrope enstatite 5 12 al2o3 al2o3 contents in reversal run pairs closely approached common values from both the high and low al sides most experiments were done in a piston cylinder device using a nacl medium some runs at very high temperatures were made in pyrex nacl or pyrex talc assemblies the measured enstatite compositions expressed as mole fractions of mg2 mgal alsi3 o12 x opy en were fitted by a monte carlo method to the equilibrium condition begin gathered delta h 970 0 970 delta s 970 0 hfill mathop smallint limits 1 p delta v 970 0 dp mathop smallint limits 970 t delta s t 0 dt rt ln x opy en 0 hfill end gathered where the best fit parameters of h s and v 1 bar 970 k for the reaction pyrope opy are 2 040 cal mol 2 12 eu and 9 55 cc mol in addition to the determination of al2o3 contents of enstatite the univariant reaction pyrope forsterite enstatite spinel was reversibly located in the range 1 100 1 400 c a best fit line passes through 22 22 5 and 25 kbar at 1 040 1 255 and 1 415 c respectively our results for the univariant reaction are in agreement with previous studies of macgregor 1974 and haselton 1979 however comparison of the experimentally determined curve with thermochemical calculations suggests that there may be a small error in the tabulated h f 970 1 0 value for enstatite a value of 8 32 rather than 8 81 kcal mole charlu et al 1975 is consistent with the present data application of garnet enstatite spinel forsterite equilibria to natural materials is fraught with difficulties the effects of nonternary components are poorly understood and the low solubilities of al2o3 in enstatite under most geologically reasonable conditions make barometric or thermometric calculations highly sensitive more detailed studies including reversed determinations in low friction assemblies are sorely needed before the effects of important diluents such as fe ca and cr can be fully understood

an unmetasomatized source for the malaitan alnoite solomon islands petrogenesis involving zone refining megacryst fractionation and assimilation of oceanic lithosphere the ma tan alnijite contains a rich and varied megacryst suite of unprecedented compositional range we have undertaken trace element and isotope modeling in order to formulate a petrogenetic scheme which links the host alniiite to its entrained megacrysts this requires that a proto alntiite magma is the product of zone refining initiated by diapiric upwelling where the initial melt passes through 200 times its volume of mantle isotopic evidence indicates the source of the proto alniiite contains a time integrated lree depleted signature 143nd 44nd 0 51274 impingement upon the rigid lithosphere halts or dramatically slows the upward progress of the mantle diapir at this point the magma cools and megacryst fractionation begins with augites crystallizingjirst followed by subcalcic diopsides and finally phlogopites garnet probably crystallizes over the entire range of clinopyroxene fractionation estimated proportions of fractionating phases are 30 augite 24 5 subcalcic diopside 27 garnet 12 9 phlogopite 5 bronzite 0 5 ilmenite and 0 1 zircon as this proto alnoite magma crystallizes it assimilates a subducted component of seawater altered basalt which underplates the ontong java plateau this is witnessed in the isotopic composition of the megacrysts and alnoite

silk road glass in xinjiang china chemical compositional analysis and interpretation using a high resolution portable xrf spectrometer abstract in this paper we explore the major minor and some trace elements of sixty five glass beads from eighteen oasis sites both north and south of the taklamakan desert the ancient centre of the silk routes linking east and west the samples date from the warring states period 475 2211 bce to the tang dynasty 618 907 ce using a high resolution portable xrf spectrometer with special attention to issues of surface weathering and sample preparation we obtained quantitative chemical compositional data that when combined with archaeological context and the technology of bead manufacture provide the basis for an understanding of both changes in glass type over time and possible source areas for the xinjiang glasses while glass beads at the early sites 1st c bce to 4th c ce were coming primarily from kushan controlled territories in northern india pakistan and afghanistan with a small contribution from central china most of the later glass 4th 10th c ce is similar to that produced in the sasanian empire at such sites as veh ardashir in central iraq these changes most likely reflect changing cultural and economic conditions in the silk road towns

investigation of iron age north eastern scottish glass beads using element analysis with la icp ms abstract class 13 and 14 iron age scottish glass beads are a group of highly decorated beads of british origin or design dating indicatively to the 1st and 2nd century ad and typically found in aberdeenshire and moray district guido 1978 85 9 their distinctive stylistic characteristics and geographical segregation renders them ideal for the investigation of whether the glasses employed in their manufacture were imported rather than produced locally and for the assessment of the technology used in the production of the deep colours studies performed in the 1980s on different specimens pertaining to the same classes henderson 1982 showed compositional characteristics differing from iron age southern british beads suggesting a different source of glass for their manufacture here a set of 19 beads which was never investigated before was analysed for 32 major minor and trace elements using laser ablation inductively coupled plasma mass spectrometry la icp ms the sample set shows good homogeneity in major and minor element composition indicating the use of imported natron glass with standardized composition typical of roman glass of the period also reflected in the recipes used for colouration evidence for the use of cullet and waste glass was found which along with the particularity of the design suggests a local origin of the beads and possible production by native glassworkers

moist convection as an energy source for the large scale motions in jupiter s atmosphere jupiter s dominant large scale weather patterns dimensions 10 000 km are zonal jets and long lived ovals the jets have been flowing east and west at constant speeds of up to 180 m s 1 for over 100 years these jets receive energy from small scale eddies which pump eastward momentum into the eastward jets and westward momentum into the westward jets this momentum transfer was predicted by numerical models before it was observed on jupiter the large ovals roll between the jets in an anticyclonic direction clockwise in the northern hemisphere and counterclockwise in the southern hemisphere where they regularly assimilate small anticyclonic eddies but from where the eddies receive their energy has been an open question here we argue that the eddies which ultimately drive both the jets and the ovals receive their energy from moist convection this hypothesis is consistent with observations of jovian lightning which is an indicator of moist convection it also explains the anticyclonic rotation and poleward drift of the eddies and suggests patterns of upwelling and downwelling that resemble the patterns of large scale axisymmetric overturning in the earth s atmosphere

a survey of small scale waves and wave like phenomena in jupiter s atmosphere detected by junocam in the first 20 orbits of the juno spacecraft around jupiter we have identified a variety of wave like features in images made by its public outreach camera junocam because of juno s unprecedented and repeated proximity to jupiter s cloud tops during its close approaches junocam has detected more wave structures than any previous surveys most of the waves appear in long wave packets oriented east west and populated by narrow wave crests spacing between crests were measured as small as 30 km shorter than any previously measured some waves are associated with atmospheric features but others are not ostensibly associated with any visible cloud phenomena and thus may be generated by dynamical forcing below the visible cloud tops some waves also appear to be converging and others appear to be overlapping possibly at different atmospheric levels another type of wave has a series of fronts that appear to be radiating outward from the center of a cyclone most of these waves appear within 5 of latitude from the equator but we have detected waves covering planetocentric latitudes between 20 s and 45 n the great majority of the waves appear in regions associated with prograde motions of the mean zonal flow juno was unable to measure the velocity of wave features to diagnose the wave types due to its close and rapid flybys however both by our own upper limits on wave motions and by analogy with previous measurements we expect that the waves junocam detected near the equator are inertia gravity waves

trace element discriminants between egyptian and mesopotamian late bronze age glasses the origins of late bronze age glass artefacts found throughout the mediterranean and near and middle east remain controversial previous analyses of major and minor elements in both egyptian and mesopotamian glasses have proven equivocal revealing no significant compositional differences between glasses from these two regions here we present new laser ablation icpms analyses of 32 trace elements in 54 samples of both egyptian and mesopotamian blue and colourless glasses our results show that there are consistent differences between these two suites which are not related to the colorant and clearly indicate the use of different raw materials and or manufacturing processes compositional variations are related to geological controls hence this method holds promise for the development of a minimally destructive technique for discriminating between archaeological glasses of different provenance which will be essential in the interpretation of ancient trade patterns and contacts

the picton and varty lake ultramafic dikes jurassic magmatism in the st lawrence platform near belleville ontario the picton and varty lake ultramafic dikes that intrude ordovician limestone near belleville ontario consist of olivine or serpentinized pseudomorphs and ti phlogopite phenocrysts set in a groundmass of spinel perovskite serpentine calcite apatite and chlorite phlogopite exhibits a complex chemical variation and late stage ba enrichment up to 6 8 wt bao spinels are chemically zoned and commonly exhibit an atoll texture in which a magnesian aluminous chromite core is separated by a silicate zone from late stage magnesian aluminous titanomagnetite chemically similar to kimberlitic spinel atoll spinels from the picton dike also have a zone of titanian pleonaste surrounding a central grain of magnesian aluminous chromite at the centre of the atoll structures both dikes are extremely silica undersaturated with high k na and mg mg fe2 ratios petrographic and chemical features of the picton and varty lake dikes preclude simple classification as both dikes have aspects indicative of kimberl

changes in jupiter s zonal wind profile preceding and during the juno mission abstract we present five epochs of wfc3 hst jupiter observations taken between 2009 2016 and extract global zonal wind profiles for each epoch jupiter s zonal wind field is globally stable throughout these years but significant variations in certain latitude regions persist we find that the largest uncertainties in the wind field are due to vortices or hot spots and show residual maps which identify the strongest vortex flows the strongest year to year variation in the zonal wind profiles is the 24 n jet peak numerous plume outbreaks have been observed in the northern temperate belt and are associated with decreases in the zonal velocity and brightness we show that the 24 n jet peak velocity and brightness decreased in 2012 and again in late 2016 following outbreaks during these years our february 2016 zonal wind profile was the last highly spatially resolved measurement prior to juno s first science observations the final 2016 data were taken in conjunction with juno s perijove 3 pass on 11 december 2016 and show the zonal wind profile following the plume outbreak at 24 n in october 2016

small lightning flashes from shallow electrical storms on jupiter lightning flashes have been observed by a number of missions that visited or flew by jupiter over the past several decades imagery led to a flash rate estimate of about 4 10 3 flashes per square kilometre per year refs 1 2 the spatial extent of voyager flashes was estimated to be about 30 kilometres half width at half maximum intensity hwhm but the camera was unlikely to have detected the dim outer edges of the flashes given its weak response to the brightest spectral line of jovian lightning emission the 656 3 nanometre h line of atomic hydrogen1 3 6 the spatial resolution of some cameras allowed investigators to confirm 22 flashes with hwhm greater than 42 kilometres and to estimate one with an hwhm of 37 to 45 kilometres refs 1 7 9 these flashes with optical energies comparable to terrestrial superbolts of 0 02 1 6 1010 joules have been interpreted as tracers of moist convection originating near the 5 bar level of jupiter s atmosphere assuming photon scattering from points beneath the clouds 1 3 7 8 10 12 previous observations of lightning have been limited by camera sensitivity distance from jupiter and long exposures about 680 milliseconds to 85 seconds meaning that some measurements were probably superimposed flashes reported as one1 2 7 9 10 13 here we report optical observations of lightning flashes by the juno spacecraft with energies of approximately 105 108 joules flash durations as short as 5 4 milliseconds and inter flash separations of tens of milliseconds with typical terrestrial energies the flash rate is about 6 1 10 2 flashes per square kilometre per year more than an order of magnitude greater than hitherto seen several flashes are of such small spatial extent that they must originate above the 2 bar level where there is no liquid water14 15 this implies that multiple mechanisms for generating lightning on jupiter need to be considered for a full understanding of the planet s atmospheric convection and composition small lightning flashes detected on jupiter by juno have shallow origins above the 2 bar level of jupiter s atmosphere where temperatures are too low for liquid water to exist

the jagersfontein cr poor megacryst suite towards a model for megacryst petrogenesis abstract major and trace element concentrations and sr and nd isotopic ratios were determined for selected cr poor megacrysts from the jagersfontein kimberlite south africa the data are consistent with fractional crystallization of the megacrysts at high pressure near the base of the mechanical boundary layer of the lithosphere from a magma of oib like affinity the host kimberlite and megacrysts are suggested to be products of the same period of plume activity in the asthenosphere but with different evolutionary histories zone refining assimilation of lithospheric melts assimilation of lithospheric and crustal fragments and near surface alteration all contribute towards the eventual hybrid composition of the kimberlite although the relative roles of these processes remain difficult to determine the host kimberlite disrupts and entrains the cr poor megacrysts and the megacrysts must therefore be considered xenocrysts in the host kimberlite

the blue ball arkansas kimberlite mineralogy petrology and geochemistry a study of the mica peridotite in blue ball scott county arkansas reveals that on the basis of mineralogy and whole rock chemistry including the rare earth elements this occurrence is a micaceous kimberlite micas occur as groundmass and phenocryst phases both are compositionally similar and characterized by reversely pleochroic rims and patches on cores with intermediate pleochroism reverse pleochroism is associated with sharp increases in feo total fe and delta t 8 si al and a sharp decrease in al 2 o 3 features consistent with the presence of tetrahedral fe 3 reverse pleochroism in the phlogopite phenocrysts is associated with resorption features mineralogical and compositional similarities between these phlogopites and those of the cumulate glimmerites including the marid nodules allows us to suggest a genetic relationship between them

jupiter s cloud structure from galileo imaging data the vertical structure of aerosols on jupiter is inferred from data obtained by the nasa galileo solid state imaging system during the first six orbits of the spacecraft images at 889 nm a strong methane band 727 nm a weaker methane band and 756 nm continuum taken at a variety of lighting and viewing angles are used the images are displayed and described in the companion paper by vasavada et al 1998 icarus 135 265 275 conservative scattering cloud particles with laterally uniform single scattering properties are assumed in the analysis and are shown to be consistent with the data at these wavelengths particles are bright and the darkest locations on jupiter correspond to the smallest optical thickness of aerosols optical depths and vertical positions of aerosol layers vary from place to place and are the retrieved quantities in the analysis only mid and low latitudes are sampled in this data set a stratospheric haze with an optical depth of roughly a tenth and an upper tropospheric haze with an optical depth of 2 to 6 exist over all regions both are consistent with previous conclusions based on data of lower spatial resolution e g west et al 1986 icarus 65 161 217 the new data show that these layers contain little lateral structure on scales smaller than the planetary jets on scales of the jets and ovals the top and bottom of the upper tropospheric haze vary in elevation the concentration of particles optical depth per pressure interval varies less than does the total optical depth near the base of the upper tropospheric haze is a third cloud component usually at pressure p 750 200 mb which is less than a scale height in geometric thickness its optical depth varies from zero to about 20 on regional scales and often varies by 50 on scales of a few tens of kilometers optical depth variations in this cloud are the principal cause of the features in jupiter s atmosphere seen at red and longer wavelengths it is probably composed of ammonia the expected nh 4sh cloud has not been identified in this work perhaps because it exists only at locations where it is concealed beneath higher clouds our retrievals also cannot rule out a pervasive deep haze without small scale structure finally in one region northwest of the great red spot a deeper cloud is identified parts of it lie at a pressure greater than four bars it is associated with a rapidly changing storm system with optical depth of several tens or more and a range of cloud heights between p 4 bars to p 400 mb it is probably composed of water

moist convection and the 2010 2011 revival of jupiter s south equatorial belt fletcher was supported by a royal society research fellowship at the university of leicester giles was supported by a royal society research grant at the university of oxford the uk authors acknowledge the support of the science and technology facilities council stfc a portion of this work was performed by orton and payne at the jet propulsion laboratory california institute of technology under a contract with nasa this research used the alice high performance computing facility at the university of leicester we are extremely grateful for the combined efforts of the numerous amateur observers including those listed in the figure captions for sharing their data and for the jupos software developed by grischa hahn and hans jorg mettig to reproject the visible light data this investigation was partially based on thermal infrared observations acquired at i the eso very large telescope paranal ut3 melipal observatory using directors discretionary time program id 286 c 5009 and regular service time program id 087 c 0024 ii the subaru telescope which is 27 operated by the national astronomical observatory of japan program id o11154 iii nasa s infrared telescope facility which is operated by the university of hawaii under contract nnh14ck55b with the national aeronautics and space administration program ids 2010b010 2011a010 2011b027 and iv observations obtained at the gemini observatory program ids gn 2010b dd 3 gs 2010b q 8 and gs 2011aq 11 which is operated by the association of universities for research in astronomy inc under a cooperative agreement with the nsf on behalf of the gemini partnership the national science foundation united states the national research council canada conicyt chile ministerio de ciencia tecnolog ia e innovacion productiva argentina and ministerio da ci encia tecnologia e inovac ao brazil we wish to recognise and acknowledge the very significant cultural role and reverence that the summit of mauna kea has always had within the indigenous hawaiian community we are most fortunate to have the opportunity to conduct observations from this mountain

cassini imaging of saturn southern hemisphere winds and vortices high resolution images of saturn s southern hemisphere acquired by the cassini imaging science subsystem between february and october 2004 are used to create maps of cloud morphology at several wavelengths to derive zonal winds and to characterize the distribution frequency size morphology color behavior and lifetime of vortices nonequatorial wind measurements display only minor differences from those collected since 1981 and reveal a strong prograde flow near the pole the region just southward of the velocity minimum at 40 7 s is especially active containing numerous vortices some generated in the proximity of convective storms the two eastward jets nearest the pole display periodicity in their longitudinal structure but no direct analogs to the northern hemisphere s polar hexagon or ribbon waves were observed characteristics of winds and vortices are compared with those of saturn s northern hemisphere and jupiter s atmosphere

dynamical implications of jupiter s tropospheric ammonia abundance abstract groundbased radio observations indicate that jupiter s ammonia is globally depleted from 0 6 bars to at least 4 6 bars relative to the deep abundance of 3 times solar a fact that has so far defied explanation the observations also indicate that i the depletion is greater in belts than zones and ii the greatest depletion occurs within jupiter s local 5 m hot spots which have recently been detected at radio wavelengths here we first show that both the global depletion and its belt zone variation can be explained by a simple model for the interaction of moist convection with jupiter s cloud layer circulation if the global depletion is dynamical in origin then important endmember models for the belt zone circulation can be ruled out next we show that the radio observations of jupiter s 5 m hot spots imply that the equatorial wave inferred to cause hot spots induces vertical parcel oscillation of a factor of 2 in pressure near the 2 bar level which places important constraints on hot spot dynamics finally using spatially resolved radio maps we demonstrate that low latitude features exceeding 4000 km diameter such as the equatorial plumes and large vortices are also depleted in ammonia from 0 6 bars to at least 2 bars relative to the deep abundance of 3 times solar if any low latitude features exist that contain 3 times solar ammonia up to the 0 6 bar ammonia condensation level they must have diameters less than 4000 km

vertical wind shear on jupiter from cassini images 1 multifilter images of jupiter acquired by the cassini imaging science subsystem iss are used to derive zonal winds at altitudes above and below the visible cloud deck small features unique to the ultraviolet images of iss are tracked to get the systematic high altitude zonal winds comparison between the zonal winds from ultraviolet images and the vertical profile of zonal winds from the cassini composite infrared spectrometer cirs shows that the zonal winds from the ultraviolet images are from a pressure level that is 0 2 scale heights higher than the pressure level of the zonal winds from continuum band images deeper zonal winds at different latitudes of the equatorial region are measured by tracking cloud features observed within hot spots on continuum band images the deeper zonal winds in this study extend the measurement of the galileo probe to different latitudes of the equatorial region comparison between the galileo probe and this study suggests that these fast moving clouds within hot spots are deeper than 3 bars and are therefore probably water clouds

atmospheric waves and dynamics beneath jupiter s clouds from radio wavelength observations abstract we observed jupiter at wavelengths near 2 cm with the karl g jansky very large array vla in february 2015 these frequencies are mostly sensitive to variations in ammonia abundance and probe between 0 5 2 0 bars of pressure in jupiter s atmosphere within and below the visible cloud deck which has its base near 0 7 bars the resultant observed data were projected into a cylindrical map of the planet with spatial resolution of 1500 km at the equator we have examined the data for atmospheric waves and observed a prominent bright belt of radio hotspot features near 10 n likely connected to the same equatorial wave associated with the 5 m hotspots we conducted a passive tracer power spectral wave analysis for the entire map and latitude regions corresponding to eastward and westward jets and compare our results to previous studies the power spectra analysis revealed that the atmosphere sampled in our observation excluding the neb region is in a 2 d turbulent regime and its dynamics are predominately governed by the shallow water equations the great red spot grs is also very prominent and has a noticeable meridional asymmetry and we compare it and nearby storms with optical images we find that the meridional radio profile has a global north south hemisphere distinction and find correlations of it to optical intensity banding and to shear zones of the zonal wind profile over select regions of latitude amateur optical images taken before and after our observation complemented the radio wavelength map to investigate dynamics of the equatorial region in jupiter s atmosphere we find that two radio hotspots at 2 cm are well correlated with optical plumes in the neb additionally revealing they are not the same 5 m hotspot features correlated with optical dark patches between adjacent plumes this analysis exploits the vla s upgraded sensitivity and explores the opportunities now possible when studying gas giants especially atmospheric dynamics of layers beneath upper level clouds