zonal motion and structure in jupiter s upper troposphere from voyager infrared and imaging observations abstract voyager infrared data are used to produce global cylindrical projection digital maps of temperature at the 270 and 150 mb pressure levels infrared cloud optical depths at 45 and 5 m wavelength and the ammonia abundance near the 680 mb level voyager imaging data are used to produce maps of orange reflectivity and violet reflectivity effective wavelengths of 0 58 and 0 41 m respectively the zonal motions of the dominant structures in each of the quantities are evaluated using cross correlation of the maps structures in the maps of cloud optical depths ammonia abundance and visible reflectivities show the same zonal motion at almost all latitudes the dominant upper tropospheric thermal structures move at a rate which is far different than the cloud indicators and they remain stationary with respect to the bulk rotation of the planet comparison of these motions with the zonally averaged thermal wind shear inthe upper troposphere indicates that the thermal structures move at a rate far different than the local fluid velocity we present a simple theory which suggests that these slowly moving thermal structures could represent the influence of a disturbance seated in a slowly moving region deep in jupiter s atmospheres although this explanation is not unique intercomparison of the motions and longitudinal alignment of the various cloud indicators with the thermal wind shear in the upper troposphere shows that the few latitudes at which differences exist correlate strikingly with latitudes of largest shear suggesting that the observed differences may reflect height differences in observed cloud features fourier analysis of the maps of temperature at 270 mb show a robust stationary feature at a zonal wavenumber of 9 near 15 n latitude the maps of cloud optical depth at 45 m show a feature at zonal wavenumber 11 near 20 n these periodicities may be related to similar structures recently detected in groundbased observations and their longevity and robustness may indicate preferred wavemodes of the atmosphere

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

jupiter s polar regions in the ultraviolet as imaged by hst wfpc2 auroral aligned features and zonal motions jupiter s polar regions are examined using ultraviolet uv 120 320 nm images obtained with the hubble space telescope wide field and planetary camera 2 over the period of 1994 1997 these images probe the stratospheric aerosols at pressures of a few tens of millibars we discovered a uv darkened segment in the polar shading just equatorward of the north polar hood that remained aligned with the southern most portion of the north auroral oval the darkened segment generally extended over 100 260 system iii longitude and 39 53 n planetocentric latitude in the f160w f218w and f255w images no single type of feature in the f218w and f255w images appeared consistently aligned within the outline of the north auroral oval but several transient features were observed it is not certain whether these transient features were associated with auroral processes or just coincidentally aligned a south dark patch was consistently observed within the outline of the south auroral oval and was temporally variable in size and shape by tracking selected features we obtained the first direct measurements of the zonal motions in jupiter s high latitude stratosphere primarily retrograde motions were observed from 41 n to 60 n both prograde and retrograde motions appeared from 48 s to 71 s we propose that the asymmetric appearance of the polar hoods r a west 1979 icarus 38 12 33 r wagener and j caldwell 1988 icarus 74 141 152 is influenced in part by meridional mixing in the stratosphere enhanced meridional mixing would tend to be more effective at dispersing the polar aerosols to lower latitudes in the north than in the south

endolithic biodegradation of cool water skeletal carbonates on scott shelf northwestern vancouver island canada abstract biodegradation of shell material is widespread in the cool water skeletal carbonate deposits on scott shelf northwestern vancouver island and is especially evident in the large aragonitic bivalves glycymeris and humilaria major primary sediment contributors ten types of endolithic microborings have been identified in the shells including representatives of green algae e g ostreobium quekettii blue green algae e g plectonema terebrans scytonema sp fungi bacteria and clionid sponges as well as macroborings of phoronids polychaetes and naticid gatropods microcrystalline carbonate is not precipitated in vacated bores boring physically weakens the shells rendering them more prone to mechanical abrasion during sediment transport and bioturbation and to biological abrasion by grazing benthos tumbling experiments demonstrate that the rate of carbonate mud production is much greater for bored as compared to fresh bivalve shells and that mud production rates decrease with tumbling time because most endolithic microborings are confined to the periphery of grains boring also increases significantly the porosity and surface area of skeletal grains and destroys their organic matrix making them susceptible to maceration and dissolution on cool water shelves fostered by the generally low rates of carbonate production and accumulation many aragonitic bivalve shells on scott shelf have become thoroughly degraded through a combination of endolithic microboring maceration and dissolution within about 1000 years in ambient sea water in geologic terms such selective taphonomic loss of skeletal material may be considerable in ancient temperate shelf limestones and should be evaluated when interpreting their paleoecology and paleoenvironments

saturn s zonal winds at cloud level we present an analysis of new cloud motion measurements in saturn s atmosphere from voyager 1 and 2 images and define a nominal zonal wind velocity vs latitude profile for the cloud top level that can be used as reference for the upcoming cassini mission improvements over previous studies include i twice the number of wind vectors used ii independent measurements of cloud tracers iii extended latitudinal coverage iv strict error control and evaluation and v a new zonal averaging methodology mean zonal wind velocities are given for the latitude range 81 to 71 planetographic in steps of 0 5 with a gap between 0 and 10 due to ring shadowing this research also includes the study of the morphology and motions of cloud systems in the equator and in the southern hemisphere which have not been described previously we give an ephemeris motion equation for several long lived features that could be observable if they survive until cassini arrives on saturn the long term behavior of the zonal wind profile is studied by comparing it with a complete set of wind velocities compiled from historical and modern ground based and hst observations significant changes are noted in the equatorial jet between this set and the nominal voyager profile we discuss in detail the possible origin for such differences

long term variation in the cloud tracked zonal velocities at the cloud top of venus deduced from venus express vmc images 1 we present observational evidence of the variation of the cloud tracked zonal velocity by 20 m s 1 with a timescale of a few hundred days in the southern low latitude region based on an analysis of cloud images taken by the venus monitoring camera on board venus express a spectral analysis suggests that the variation has a periodicity with a period of about 255 days although cloud features are not always passive tracers the periodical variation of the dynamical state is a robust feature superposed on this long term variation of the zonal velocity kelvin wave like disturbances tend to be observed in periods of relatively slow background velocity while rossby wave like disturbances tend to be observed in periods of fast background velocity since the momentum deposition by these waves can accelerate and decelerate the mean flow these waves may contribute to the suggested long term oscillation

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

saturn s cloud structure and temporal evolution from ten years of hubble space telescope images 1994 2003 abstract we present a study of the vertical structure of clouds and hazes in the upper atmosphere of saturn s southern hemisphere during 1994 2003 about one third of a saturn year based on hubble space telescope images the photometrically calibrated wfpc2 images cover the spectral region between the near uv 218 255 nm and the near ir 953 1042 nm including the 890 nm methane band using a radiative transfer code we have reproduced the observed center to limb variations in absolute reflectivity at selected latitudes which allowed us to characterize the vertical structure of the entire hemisphere during this period a model atmosphere with two haze layers has been used to study the variation of hazes with latitude and to characterize their temporal changes both hazes are located above a thick cloud putatively composed of ammonia ice an upper thin haze in the stratosphere between 1 and 10 mbar is found to be persistent and formed by small particles radii 0 2 m the lower thicker haze close to the tropopause level shows a strong latitudinal dependence in its optical thickness typically 20 40 at the equator but 5 at the pole at 814 nm this tropospheric haze is blue absorbent and extends from 50 to 100 mbar to about 400 mbar both hazes show temporal variability but at different time scales first there is a tendency for the optical thickness of the stratospheric haze to increase at all latitudes as insolation increases second the tropospheric haze shows mid term changes over time scales from months to 1 2 years in its optical thickness typically by a factor of 2 such changes always occur within a rather narrow latitude band width 5 10 affecting almost all latitudes but at different times third we detected a long term 10 year decrease in the blue single scattering albedo of the tropospheric haze particles most intense in the equatorial and polar areas long term changes follow seasonal insolation variations smoothly without any apparent delay suggesting photochemical processes that affect the particles optical properties as well as their size in contrast mid term changes are sudden and show various time scales pointing to a dynamical origin

cassini iss observation of saturn s north polar vortex and comparison to the south polar vortex we present analyses of saturn s north pole using high resolution images captured in late 2012 by the cassini spacecraft s imaging science subsystem iss camera the images reveal the presence of an intense cyclonic vortex centered at the north pole in the red and green visible continuum wavelengths the north polar region exhibits a cyclonically spiraling cloud morphology extending from the pole to 85 n planetocentric latitude with a 4700 km radius images captured in the methane bands which sense upper tropospheric haze show an approximately circular hole in the haze extending up to 1 5 latitude away from the pole the spiraling morphology and the eye like hole at the center are reminiscent of a terrestrial tropical cyclone in the system iii reference frame rotation period of 10h39m22 4s seidelmann et al 2007 archinal et al 2011 the eastward wind speed increases to about 140 m s 1 at 89 n planetocentric latitude the vorticity is 6 5 1 5 10 4 s 1 at the pole and decreases to 1 3 1 2 10 4 s 1 at 89 n in addition we present an analysis of saturn s south polar vortex using images captured in january 2007 to compare its cloud morphology to the north pole the set of images captured in 2007 includes filters that have not been analyzed before images captured in the violet filter 400 nm also reveal a bright polar cloud the south polar morphology in 2007 was more smooth and lacked the small clouds apparent around the north pole in 2012 saturn underwent equinox in august 2009 the 2007 observation captured the pre equinox south pole and the 2012 observation captured the post equinox north pole thus the observed differences between the poles are likely due to seasonal effects if these differences indeed are caused by seasonal effects continuing observations of the summer north pole by the cassini mission should show a formation of a polar cloud that appears bright in short wavelength filters

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

global context of the galileo e6 observations of jupiter s white ovals galileo solid state imaging ssi data taken during the e6 orbit on february 19 1997 offer a brief high resolution glimpse of jupiter s white ovals these data can be used to infer relative cloud heights and systematic rotations over a small area of latitude and longitude approximately 20 by 30 around the white ovals to fully understand the behavior of these cloud systems however a longer time span of global data is necessary in this paper we utilize ground based voyager and hubble space telescope data to interpret the galileo images we find that the white ovals translation rates have slowed from 0 39 deg day 1during the voyager era to 0 13 deg day 1in 1996 and they along with three smaller anticyclonic systems have coalesced into a system of alternating cyclonic and anticyclonic systems that has not been observed before the largest of the ovals bc is now impeding the eastward motion of the system causing more rapidly translating anticyclonic cells to catch the system and increase the westward extension of the equally spaced features rotational velocities for bc and a small anticyclonic system at 42 s have also been measured and peak at 120 m sec 1for both systems comparable to the mitchellet al j geophys res 86 8751 8757 measurements of bc and the great red spot grs from voyager data the motion of individual features and of the whole system in the ambient wind flow is discussed

jupiter s interior and deep atmosphere the initial pole to pole passes with the juno spacecraft on 27 august 2016 the juno spacecraft acquired science observations of jupiter passing less than 5000 kilometers above the equatorial cloud tops images of jupiter s poles show a chaotic scene unlike saturn s poles microwave sounding reveals weather features at pressures deeper than 100 bars dominated by an ammonia rich narrow low latitude plume resembling a deeper wider version of earth s hadley cell near infrared mapping reveals the relative humidity within prominent downwelling regions juno s measured gravity field differs substantially from the last available estimate and is one order of magnitude more precise this has implications for the distribution of heavy elements in the interior including the existence and mass of jupiter s core the observed magnetic field exhibits smaller spatial variations than expected indicative of a rich harmonic content

bathymetric zonation of modern microborers in dead coral substrates from new caledonia implications for paleodepth reconstructions in holocene corals abstract microboring endoliths were studied in dead modern corals collected at various depths and in growth position on la surprise atoll in new caledonia eight taxa of microborers were regularly observed three cyanobacteria hyella caespitosa mastigocoleus testarum and plectonema terebrans two chlorophytes ostreobium quekettii and phaeophila dendroides and three fungal forms dodgella priscus and two unidentified fungi the relative abundance of each taxon was determined in the modern corals throughout the studied sampling interval from 0 down to 40 m water depth this allowed us to propose for the first time a bathymetric model based on microendolith assemblages colonizing in situ hard substrates of corals in this model the occurrence of the cyanobacteria hyella and mastigocoleus indicates a bathymetric range from 0 down to a water depth of 3 and 6 m respectively the chlorophyta o quekettii associated with the cyanobacterium p terebrans and fungi is dominant from 10 to 40 m depth which is the lower limit of our sampling the distribution ranges of individual taxa observed in the dead coral substrates from new caledonia are much narrower than those reported in the literature for other substrates the bathymetric model based on distribution of microborers in modern corals was then applied to interpret the trace assemblages of microborers observed in holocene corals collected by drilling on two reef sites of new caledonia la surprise islet in the vicinity of the sampling sites of the modern corals and the barrier reef of bayes on the ne coast of grande terre the paleodepth interpretations performed at various levels along the cores allow identification of several shallowing upward sequences during the last 7000 years of reef growth in new caledonia differences in the thickness of these sequences between la surprise and bayes sites were interpreted as differences in the space available for accommodation between the two sites in turn related to the differential subsidence that affected new caledonia during holocene times the use of the microendolith trace assemblages in paleodepth reconstructions of holocene reefs from new caledonia allowed detection of relative sea level variations finer than those deduced from changes in coralgal assemblages

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

cloud features and zonal wind measurements of saturn s atmosphere as observed by cassini vims 1 we present an analysis of data about saturn s atmosphere from cassini s visual and infrared mapping spectrometer vims focusing on the meteorology of the features seen in the 5 m spectral window we present vims mosaics and discuss the morphology and general characteristics of the features backlit by saturn s thermal emission we have also constructed a zonal wind profile from vims feature tracking observation sequences using an automated cloud feature tracker comparison with previously constructed profiles from voyager and cassini imaging data reveals broad similarities suggesting minimal vertical shear of the zonal wind however areas of apparent wind shear are present in the vims zonal wind profile at jet stream cores in particular our analysis shows that the equatorial jet reaches speeds exceeding 450 m s 1 similar to speeds obtained during the voyager era this suggests that recent inferences of relatively slower jet speeds of 275 375 m s 1 are confined to the upper troposphere and that the deep 1 bar jet has not experienced a significant slowdown our measurements of the numerous dark spotted features seen in the vims mosaics reveals that most of these features have diameters less than 1000 km and reside in confined zonal bands between jet stream cores we propose that these spot features are vortices and that vims and imaging science subsystem are sensing the same vortices at two different pressure levels the local structure at the zonal jet streams remains complex as vims may be sensing cloud features that are deeper than the nh3 cloud deck

the vertical structure of jupiter s equatorial zonal wind above the cloud deck derived using mesoscale gravity waves 1 data from the galileo probe collected during its descent into jupiter s atmosphere is used to obtain a vertical profile of the zonal wind from 0 5 bar upper troposphere to 0 1 bar lower thermosphere at the probe entry site this is accomplished by constructing a map of gravity wave lomb scargle periodograms as a function of altitude the profile obtained from the map indicates that the wind speed above the visible cloud deck increases with height to 150 m s 1 and then levels off at this value over a broad altitude range the location of the turbopause as a region of wide wave spectrum is also identified from the map in addition a cross equatorial oscillation of a jet which has previously been linked to the qqo in the stratosphere is suggested by the profile

first measurements of jupiter s zonal winds with visible imaging spectroscopy abstract we present the first measurements of jupiter s wind profile ever obtained with doppler velocity measurements in the visible hitherto knowledge about atmospheric dynamics has been obtained with cloud tracking techniques which consist of tracking visible features from images taken at different dates however cloud tracking indicates the motion of large cloud structures which is an indication of the speed of iso pressure regions rather than the speed of the actual atmospheric particles doppler imaging is as challenging motions are usually less than 100 m s 1 as appealing because it measures the speed of cloud particles instead of large cloud structures significant difference could appear in the case of atmospheric waves interfering with cloud structures here we present the first scientific results of a doppler imaging spectrometer that is dedicated to giant planet seismology and atmospheric dynamics by providing instantaneous line of sight velocity maps of the planets of the solar system the instrument has been developed in the framework of the projects jovial jovian oscillations through velocity images at several longitudes and jive in nm jovian interiors from velocimetry experiment in new mexico it is a fourier transform spectrometer with a fixed optical path difference working in the mid visible domain which monitors the position of solar fraunhofer lines that are reflected in the planets upper atmospheres after describing the instrument principle and the different steps of data reduction we report measurement of the average zonal wind speed of jupiter as a function of latitude from datasets obtained in 2015 and 2016 with two different telescopes when the planet was close to its opposition our results are consistent between the two years we compare the results with wind profiles obtained by cloud tracking on hst hubble space telescope images taken at the same epoch and identify a significant discrepancy in the north equatorial belt and northern part of the equatorial zone

a comparison of red spots in the atmosphere of jupiter abstract comparative broadband relative photometry has been obtained for the great red spot a well developed little red spot at 19 2 planetographic or 16 9 planetocentric latitude and selected belts and zones these results reveal the presence of a uv absorber in both the grs and the lrs that is not present in the belts mapping of the latitudinal dimensions obtained from measurements of ground based photographs onto the latitudinal dependence of zonal winds derived from the voyager data indicates that the position of the lrs and grs relative to the zonal winds is similar and suggest that the lrs is an anticyclonic system questions raised by this analysis are presented for further investigation

the evolving flow of jupiter s white ovals and adjacent cyclones abstract we present results regarding the dynamical meteorology of jupiter s white ovals at different points in their evolution starting from the era with three white ovals fa bc and de galileo continuing to the post merger epoch with only one oval ba cassini and finally to oval ba s current reddened state new horizons we demonstrate that the dynamics of their flow have similarly evolved along with their appearance in the galileo epoch oval de had an elliptical shape with peak zonal wind speeds of 90 m s 1 in both its northern and southern peripheries during the post merger epoch oval ba s shape was more triangular and less elliptical than oval de in addition to widening in the north south direction its northern periphery was 20 m s 1 slower and its southern periphery was 20 m s 1 faster than oval de s flow during the galileo era finally in the new horizons era the reddened oval ba had evolved back to a classical elliptical form the northern periphery of oval ba increased in speed by 20 m s 1 from cassini to new horizons ending up at a speed nearly identical to that of the northern periphery of oval de during galileo however the peak speeds along the southern rim of the newly formed oval ba were consistently faster than the corresponding speeds in oval de and they increased still further between cassini and new horizons ending up at 140 150 m s 1 relative vorticity maps of oval ba reveal a cyclonic ring surrounding its outer periphery similar to the ring present around the great red spot the cyclonic ring around oval ba in 2007 appears to be moderately stronger than observed in 1997 and 2001 suggesting that this may be associated with the coloration of the vortex the modest strengthening of the winds in oval ba the appearance of red aerosols and the appearance of a turbulent cyclonic feature to oval ba s northwest create a strong resemblance with the great red spot from both a dynamical and morphological perspective in addition to the white ovals we also measure the winds within two compact cyclonic regions one in the galileo data set and one in the cassini data set in the images these cyclonic features appear turbulent and filamentary but our wind field reveals that the flow manifests as a coherent high speed collar surrounding relatively quiescent interiors our relative vorticity maps show that the vorticity likewise concentrates in a collar near the outermost periphery unlike the white ovals which have peak relative vorticity magnitudes near the center of the vortex the cyclones contain several localized bright regions consistent with the characteristics of thunderstorms identified in other studies although less studied than their anticyclonic cousins these cyclones may offer crucial insights into the planet s cloud level energetics and dynamical meteorology

dynamics of jupiter s equatorial region at cloud top level from cassini and hst images abstract we present a study of the equatorial region of jupiter between latitudes 15 s and 15 n based on cassini iss images obtained during the jupiter flyby at the end of 2000 and hst images acquired in may and july 2008 we examine the structure of the zonal wind profile and report the detection of significant longitudinal variations in the intensity of the 6 n eastward jet up to 60 m s 1 in cassini and hst observations these longitudinal variations are in the hst case associated with different cloud morphology photometric and radiative transfer analysis of the cloud features used as tracers in hst images show that at most there is only a small height difference no larger than 0 5 1 scale heights between the slow 100 m s 1 and fast 150 m s 1 moving features this suggests that speed variability at 6 n is not dominated by vertical wind shears but instead we propose that rossby wave activity is the responsible for the zonal variability removing this variability we find that jupiter s equatorial jet is actually symmetric relative to equator with two peaks of 140 150 m s 1 located at latitudes 6 n and 6 s and at a similar pressure level we also study the local dynamics of particular equatorial features such as several dark projections associated with 5 m hot spots and a large long lived feature called the white spot ws located at 6 s convergent flow at the dark projections appears to be a characteristic which depends on the particular morphology and has only been detected in some cases the internal flow field in the white spot indicates that it is a weakly rotating quasi equatorial anticyclone relative to the ambient meridionally sheared flow

far traveled latest cretaceous paleocene conglomerates of the southern rocky mountains usa record of transient laramide tectonism a solitary thin widespread conglomerate is found in latest cretaceous paleocene sections in each of these laramide basins of the southern rockies the table cliff northwestern kaiparowits plateau and uinta basin utah the piceance creek and denver basins colorado and the san juan basin new mexico these units are unusual compared to typical syntectonic conglomerates in that they occur as a thin interval underlain by a disconformity are far traveled across most of the length of their basins generally reflect a change in dispersal direction relative to underlying deposits and were deposited during a period of reduced subsidence all units were deposited well after local initiation of the laramide orogeny but within 8 m y of each other however each conglomerate unit was separately derived from individual source areas and is not part of a once continuous gravel sheet similar widespread conglomerate units of this age are apparently absent in other rocky mountain laramide basins previous studies postulate the shallow subduction of an oceanic plateau the conjugate shatsky rise beneath the u s cordillera during the time interval of conglomerate deposition the distribution timing and dispersion directions of the far traveled conglomerates are grossly consistent with vertical motions and surface tilting along the transport path of the oceanic plateau an exact match of conglomerate timing differs from previously proposed models but uncertainties in timing of deposits and the lack of constraints on the shape and structure of the subducted plateau preclude our ability to further refine the comparison elsewise local tectonic activity climate change and sea level fluctuations fail to explain the observed spatiotemporal pattern hence we suggest that these deposits record a transient mantle derived tectonic effect traversing the rocky mountain region and demonstrate the utility of stratigraphy as a record of subtle tectonic events

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

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

comparison of the structure and dynamics of jupiter s great red spot between the voyager 1 and 2 encounters abstract we have consistently navigated the highest resolution images available of jupiter s great red spot grs from the voyager iss experiment from them we have measured apparent displacements of cloud features around and within the red spot which can be interpreted as wind vectors we have used the wind field information to determine the circulation characteristics of the collar and to map the relative vorticity and horizontal divergence of the central grs region color ratios and ground based data have been used to complement these observations derived quantities from the iris data set taken simultaneously with the voyager images have been obtained in order to determine the thermal structure infrared cloud opacity nh 3 abundance and para h 2 fraction above the great red spot there is evidence of non chaotic activity in the central region of the red spot small eddy structures consisting of coherent cloud features with apparently two dimensional turbulent motions are present in this region along with larger classical cyclonic vortices the surrounding anticyclonic collar circulates with higher velocities and appears to be detached from the core by an abrupt transition region the central region appears to be elevated over the surrounding collar and exhibits evidence for upwelling and some outflow of material differences in the collar structure and velocity profiles between the voyager encounters can be attributed to differences in the ingestion rate of westward moving south equatorial belt vortices caused by a blocking south tropical zone disturbance which moving eastward overtook and passed the red spot between the two encounters this disturbance appears to temporarily increase in brightness during conjunctions with the red spot and has been tracked for 20 years

meteorology of jupiter s equatorial hot spots and plumes from cassini we present an updated analysis of jupiter s equatorial meteorology from cassini observations for two months preceding the spacecraft s closest approach the imaging science subsystem iss onboard regularly imaged the atmosphere we created time lapse movies from this period in order to analyze the dynamics of equatorial hot spots and their interactions with adjacent latitudes hot spots are relatively cloud free regions that emit strongly at 5 lm improved knowledge of these features is crucial for fully understanding galileo probe measurements taken during its descent through one hot spots are quasistable rectangular dark areas on visible wavelength images with defined eastern edges that sharply contrast with surrounding clouds but diffuse western edges serving as nebulous boundaries with adjacent equatorial plumes hot spots exhibit significant variations in size and shape over timescales of days and weeks some of these changes correspond with passing vortex systems from adjacent latitudes interacting with hot spots strong anticyclonic gyres present to the south and southeast of the dark areas appear to circulate into hot spots impressive bright white plumes occupy spaces in between hot spots compact cirrus like scooter clouds flow rapidly through the plumes before disappearing within the dark areas these clouds travel at 150 200 m s 1 much faster than the 100 m s 1 hot spot and plume drift speed this raises the possibility that the scooter clouds may be more illustrative of the actual jet stream speed at these latitudes most previously published zonal wind profiles represent the drift speed of the hot spots at their latitude from pattern matching of the entire longitudinal image strip if a downward branch of an equatorially trapped rossby wave controls the overall appearance of hot spots however the westward phase velocity of the wave leads to underestimates of the true jet stream speed

jupiter s zonal winds are they bands of homogenized potential vorticity organized as a monotonic staircase the east west striped pattern of clouds in jupiter s weather layer is accompanied by a zonal flow containing 12 eastward going jet streams alternating in latitude with westward going jet streams based on theory simulation and observations of the earth s oceans and atmosphere it is conjectured that jupiter s weather layer is made of bands of constant potential vorticity pv where the interfaces between bands are at the latitudes of the maxima of the eastward going jet streams it is speculated that the mixing of pv on jupiter is analogous to the mixing of salt in the ocean by the phillips effect which causes the salt density to form a monotonic staircase it is hypothesized that the pv in jupiter s weather layer is also a staircase decreasing from north to south pv is a function of vorticity as well as parameters with unknown values e g the vertical stratification and the zonal flow beneath the observable weather layer therefore these hypotheses cannot be tested directly using an atmospheric model that contains these unknown parameters we solved the inverse problem and found values of the unknown parameters and their uncertainties that best fit jovian observations the unknown parameters influence how the zonal flow interacts with large vortices e g the great red spot grs the largest and longest lived jovian vortex centred at 23 s and the oval ba the second largest vortex centred at 33 s although we found that the pv distribution is approximately piecewise constant and that the peaks of the eastward going jet streams are at the latitudes of pv interfaces there is also a pv interface at 20 s where there is a westward going jet stream we find that the zonal pv is not a monotonic staircase due to the backwards interface at 20 s we show that this backwards interface is necessary to make the grs nearly round and that without that interface the red spot would be highly elongated in the east west direction and probably unstable

paleobathymetric implications of microborings in tertiary strata of alaska usa abstract microboring algae bacteria and fungi that lived under non tropical conditions are abundantly present in four richly fossiliferous marine strata of paleocene to miocene age in alaska by comparing their boring trace communities with endolithic guide ichnocoenoses characterizing various photic zones which have been previously defined mainly in tropical and subtropical environments the alaska strata can be placed in bathymetric zones as follows the lower upper paleocene prince creek formation in the dysphotic zone the lower oligocene stepovak formation in the shallow euphotic zone shallow euphotic zone iii and the upper miocene tachilni formation in the deep euphotic zone these interpretations agree very well with bathymetric reconstructions inferred from other criteria a fourth formation the lower middle miocene narrow cape formation contains only heterotrophic microborers as if it had been deposited in the aphotic zone in contrast to previous reconstructions in this formation the periostracum of the mollusc shells is exceptionally well preserved this may explain the absence of boring algae because only heterotrophs can penetrate through organic shell layers the absolute depth ranges of these ichnocoenoses zones are inferred from their ranges in comparable latitudes of the modern north atlantic the most important features of bathymetrically controlled tropical and subtropical guide ichnocoenoses are also present at the non tropical alaskan sites although some boring algae that are widespread in tropical realms are absent

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

dynamics of saturn s polar regions we analyze data retrieved by the imaging science system onboard the cassini spacecraft to study the horizontal velocity and vorticity fields of saturn s polar regions latitudes 60 90 n in june december 2013 and 60 90 s in october 2006 and july december 2008 including the northern region where the hexagonal wave is prominent with the aid of an automated two dimensional correlation algorithm we determine two dimensional maps of zonal and meridional winds and deduce vorticity maps we extract zonal averages of zonal winds providing wind profiles that reach latitudes as high as 89 5 in the south and 89 9 in the north wind measurements cover the intense polar cyclonic vortices that reach similar peak velocities of 150 m s 1 at 88 5 the hexagonal wave lies in the core of an intense eastward jet at planetocentric latitude 75 8 n with motions that become nonzonal at the hexagonal feature in the south hemisphere the peak of the eastward jet is located at planetocentric latitude 70 4 s a large anticyclone the south polar spot sps similar to the north polar spot nps observed at the voyager times 1980 1981 has been observed in images from april 2008 to january 2009 in the south polar region at latitude 66 1 close to the eastward jet the sps does not apparently excite a wave on the jet we analyze the stability of the zonal jets finding potential instabilities at the flanks of the eastward jets around 70 and we measure the eddy wind components suggesting momentum transfer from eddy motion to the westward jets closer to the poles

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

interior ramp supported uplifts implications for sediment provenance in foreland basins the composition of syntectonic conglomerates in foreland basin sequences is strongly controlled by the lithology of strata exposed to erosion in uplifted thrust plates consideration of the styles and mechanisms of uplift in thrust belts combined with knowledge of sediment provenance and dispersal in eroding thrusted terranes leads to the concept of interior ramp supported uplift as a potential mechanism for generating syntectonic conglomerates in foreland basins interior ramp supported uplift occurs when an older inactive thrust plate that is part of the upper plate of a younger active thrust is transported over a ramp in the younger thrust uplift and folding of the inactive thrust plate re establish the older thrusted terrane as a sediment source area this mechanism is utilized to account for the deposition of a thick accumulation of quartzite clast conglomerate harebell and pinyon formations in the sevier foreland basin of northwestern wyoming other hypotheses of uplift erosion deposition suggested to explain the origin of these deposits include 1 basement involved uplift 2 progressive clast recycling through multiple episodes of fluvial transport during uplift on successive thrust plates and 3 direct transport from the toe of active thrusts although these mechanisms all undoubtedly operate in eroding thrusted terranes each has limitations to its potential validity as source for quartzite debris in the northwestern wyoming foreland basin the concept of interior ramp supported uplift alleviates many of the inconsistencies of other models and is compatible with observations elsewhere in the cordilleran thrust belt the interior uplift model also implies that uplift of an older inactive thrusted terrane over ramps of active thrusts may be the primary factor in the development of topographic relief in fold thrust belts

new observational results concerning jupiter s great red spot the changing size and aspect ratio of the great red spot from 1880 to 2000 are reviewed indicating that the length of the system has decreased significantly over the last 100 years and continues to decrease at present at a rate of 0 19 degrees per year voyager iris maps of para hydrogen fraction and potential temperature over the system are presented showing the internal structure and surrounding areas at pressures from 100 to 500 mbars in these maps the grs appears as a cold temperature anomaly and a low para fraction anomaly vertical structure analyses and wind velocity measurements are presented from data acquired by the galileo spacecraft in 1996 and 2000 respectively the vertical structure data suggest a very thick white cloud deck with a top near 800 100 mbars and an extended blue absorbing optically thick haze up to about 200 mbars with a thin stratospheric haze above it the wind field shows a substantial increase in the maximum tangential velocity from 150 to 190 m s 1 over the galileo time period the vertical structure analyses from galileo data and the wind and temperature fields from voyager data all show evidence of a tilt to the great red spot at the cloud deck from north to south and more subtly from east to west the data support the hypothesis of the grs as a tilted pancake with temporal variability to the tilt

a disturbance in jupiter s high speed north temperate jet during 1990 abstract during february 1990 a remarkable disturbance developed in the strongest jovian atmospheric jet located at 24 n planetographic latitude our telescopic images at visible wavelenghts revealed the outbreak of two bright features with an initial length scale 6000km the first discovered on february 10 and the second a week later both resided on the peak of the eastward jet drifting rapidly with zonal velocities of 165 and 170 m sec 1 respectively to the west of these bright features a pattern of alternating dark and light spots developed over the next few days these features moved with a lower mean velocity of 108 m sec 1 and had a mean east west length of 10 000 km their separation in longitude showed a bimodal distribution with peaks at 12 600 and 19 700 km the disturbance expanded zonally encircling the whole latitudinal band at 24 n 3 months after its outburst generating a new temperate belt we suggest that the two bright spots were the result of a localized convective instability while the dark spots may reflect a wave disturbance that was generated by the onset of convection

cenozoic contractional reactivation of mesozoic extensional structures in the eastern cordillera of colombia 1 the eastern cordillera of colombia is key to understanding the role of inherited basement anisotropies in the evolution of active noncollisional mountain belts in particular the rio blanco guatiquia region of the eastern cordillera is exemplary in displaying a variety of phenomena that document the importance of the orientation geometry and segmentation of preorogenic anisotropies we document the first unambiguous evidence that extensional basement structures played an important role in determining the locus of deformation during contractional reactivation in the eastern cordillera detailed structural field mapping and analysis of industry seismic reflection profiles have helped to identify the inherited san juanito naranjal and servita normal faults and associated transfer faults as important structures that were inverted during the cenozoic andean orogeny apparently the more internal faults in the former rift basin were not properly oriented for an efficient reactivation in contraction however these faults have a fundamental role as strain risers as folding is concentrated west of them in contrast reactivated normal faults such as the more external servita fault are responsible for uplifting the eastern flank of the eastern cordillera in addition these structures are adjacent and intimately linked to the development of thin skinned faults farther east in part the superimposed compression in this prestrained extensional region is compensated by lateral escape the dominant presence of basement involved buckling and thrusting and the restricted development of thin skinned thrusting in this inversion orogen makes the eastern cordillera a close analog to the intraplate atlas mountains of morocco and other inverted sectors of the andean orogen farther south

potential vorticity and layer thickness variations in the flow around jupiter s great red spot and white oval bc layer thickness variations in jupiter s atmosphere are investigated by treating potential vorticity as a conserved tracer starting with the horizontal velocity field measured from voyager images fluid trajectories around the great red spot grs and white oval bc are calculated the flow is assumed to be frictionless adiabatic hydrostatic and steady in the reference frame of the vortex absolute vorticity is followed along each trajectory its magnitude is assumed to vary directly as the thickness which is defined as the mass per unit area between potential temperature surfaces to the accuracy of the observations the inferred thickness is a separable function of trajectory and latitude the latitude dependence has positive curvature near the grs and bc the relative variations of thickness with respect to latitude are generally larger than the relative variations of coriolis parameter with respect to latitude the beta effect the data are a useful diagnostic which will help differentiate between models of jovian vortices the present analysis employs a quasi geostrophic model in which a thin upper weather layer which contains the vortex is supported hydrostatically by a much deeper lower layer in this model the upper free surface does not contribute to the observed variation of thickness along trajectories such variations are due exclusively to bottom topography flow of the deep lower layer relative to the vortex the observation are used to infer the form of the deep zonal velocity profile vs latitude the magnitude of the profile depends on the unknown static stability the principal result is the existence of horizontal shear in the deep layer zonal velocity profile i e the lower layer is not in solid body rotation and does not act like a flat solid surface in this respect the data support the hypothesis of ingersoll and cuong concerning motions in the deep layer however at some latitudes the data violate ingersoll and cuong s criterion governing the compactness of the vortices at these latitudes the topography allows standing rossby waves wakes extending far downstream to the west observed wavelike features the filamentary regions are possibly formed by this mechanism

long distance longitudinal transport of gravel across the cordilleran thrust belt of montana and idaho two newly identified middle eocene paleovalleys 100 km long preserved on top of the southwest montana reentrant of the cordilleran fold and thrust belt indicate long lived longitudinal flow across the thrust belt and resolve a long standing debate about the source of the voluminous quartzite debris in the upper cretaceous to lower tertiary divide harebell and pinyon conglomerates of montana idaho and wyoming geologic mapping stratigraphic provenance and geochronologic studies revealed that eocene volcanic and sedimentary rocks in the paleovalleys are as thick as 2 km onlap preexisting bedrock and interfinger with well rounded conglomerate derived from formations exposed only to the west the middle eocene paleovalleys are the youngest expression of a major paleoriver system that transported sediment toward the foreland during the sevier orogeny an eocene subcrop map shows that the headwaters of the eocene paleovalleys coincided with structural culminations in the thrust belt that supplied sediment to the divide conglomerate of the upper cretaceous to lower tertiary beaverhead group ultimately the lemhi pass and hawley creek paleovalleys provided several thousand cubic kilometers of quartzite debris to the pinyon and harebell conglomerates of northwest wyoming 200 350 km away and formed the northwest half of a giant longitudinal drainage system sevier contraction not the rising idaho batholith first uplifted vast culminations beneath the headwaters of this river system

changes in jupiter s zonal velocity between 1979 and 2008 abstract we show that the peak velocity of jupiter s visible cloud level zonal winds near 24 n planetographic increased from 2000 to 2008 this increase was the only change in the zonal velocity from 2000 to 2008 for latitudes between 70 that was statistically significant and not obviously associated with visible weather we present the first automated retrieval of fast 130 m s 1 zonal velocities at 8 n planetographic latitude and show that some previous retrievals incorrectly found slower zonal winds because the eastward drift of the dark projections associated with 5 m hot spots fooled the retrieval algorithms we determined the zonal velocity in 2000 from cassini images from nasa s planetary data system using a global method similar to previous longitude shifting correlation methods used by others and a new local method based on the longitudinal average of the two dimensional velocity field we obtained global velocities from images acquired in may 2008 with the wide field planetary camera 2 wfpc2 on the hubble space telescope hst longer term variability of the zonal winds is based on comparisons with published velocities based on 1979 voyager 2 and 1995 1998 hst images fluctuations in the zonal wind speeds on the order of 10 m s 1 on timescales ranging from weeks to months were found in the 1979 voyager 2 and the 1995 1998 hst velocities in data separated by 10 h we find that the east west velocity uncertainty due to longitudinal fluctuations are nearly 10 m s 1 so velocity fluctuations of 10 m s 1 may occur on timescales that are even smaller than 10 h fluctuations across such a wide range of timescales limit the accuracy of zonal wind measurements the concept of an average zonal velocity may be ill posed and defining a temporal mean zonal velocity as the average of several zonal velocity fields spanning months or years may not be physically meaningful at 8 n we use our global method to find peak zonal velocities of 110 m s 1 in 2000 and 130 m s 1 in 2008 zonal velocities from 2000 cassini data produced by our local and global methods agree everywhere except in the vicinity of 8 n there the local algorithm shows that the east west velocity has large variations in longitude vast regions exceed 140 m s 1 our global algorithm and all of the velocity extraction algorithms used in previously published studies found the east west drift velocities of the visible dark projections rather than the true zonal velocity at the visible cloud level therefore the apparent increase in zonal winds between 2000 and 2008 at 8 n is not a true change in zonal velocity at 7 3 n the galileo probe found zonal velocities of 170 m s 1 at the 3 bar level if the true zonal velocity at the visible cloud level at this latitude is 140 m s 1 rather than 105 m s 1 then the vertical zonal wind shear is much less than the currently accepted value

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

merging circulations on jupiter observed differences between cyclonic and anticyclonic mergers abstract the dynamics of mergers of large circulations in jupiter s atmosphere may permit different models of the atmosphere to be tested we report well resolved observations of such events at visible wavelengths three anticyclonic and three cyclonic events a merger of anticyclonic white ovals in the south south temperate domain 2002 march is compared with the previously reported merger of ovals be and fa in the south temperate domain 2000 march in each case the two similar sized ovals converged rapidly once they were separated by less than the sum of their diameters they orbited around each other anticyclonically during the merger the merged oval initially had the same rapid drift as the western parent and in an unexpected similarity a cyclonic oval emerged westward from the point of merger evidence suggests that a merger of smaller ovals in the north north temperate domain 2002 february had similar dynamics in contrast mergers of cyclonic ovals in the north equatorial belt barges 2001 november 2005 may proceeded in a different manner the two parent barges showed no consistent acceleration towards each other as they converged on contact there was no obvious sign of mutual circulation and the low albedo regions had almost passed each other before they finally merged and the resulting barge had a drift rate intermediate between the two parents and a length that was greater than either parent again a third such event involving a smaller barge 2002 december showed many of the same characteristics these observations define different dynamical behaviour during anticyclonic and cyclonic mergers

the jovian anticyclone ba i motions and interaction with the grs from observations and non linear simulations abstract a study of the dynamics of the second largest anticyclone in jupiter oval ba and its red colour change that occurred in late 2005 is presented in a three part study the first part this paper deals with its long term kinematical and dynamical behaviour monitored since its formation in 2000 to september 2008 using ground based observations archived at the public international outer planet watch iopw database the vortex changed its zonal drift velocity from 1 8 m s 1 in the period 2000 2002 to 0 8 m s 1 in 2002 2003 and to 2 5 m s 1 since late 2003 it also migrated southwards by 1 0 0 5 in latitude between 2000 and 2004 remaining afterwards at an almost fixed latitude position during the period 2000 2007 the oval also changed its triangular like shape to a more symmetrical one no latitudinal change was found in the months before the development of a red annulus in its interior the colour change took place in less than 5 months in 2005 2006 and no red colour feature was observed to have been present or entrained by ba months before the annulus development after detailed examination of the four encounters between ba and grs that took place during this 9 year period we did not detect any noticeable change in its drift rate or in apparent structure associated with the encounters at cloud level also the area of ba did not significantly change in this period additionally we found that ba displays a long term oscillation of 160 days in its longitude position with peak to peak amplitude of 1 2 numerical experiments using the global circulation model epic reproduce accurately the shape connecting it to its latitude migration and morphology of the oval and confirm that no strong interaction between ba and the grs is possible at least in the current situation

saturn s zonal wind profile in 2004 2009 from cassini iss images and its long term variability abstract five years of cassini imaging science subsystem images from 2004 to 2009 are analyzed in this work to retrieve global zonal wind profiles of saturn s northern and southern hemispheres in the methane absorbing bands at 890 and 727 nm and in their respective adjacent continuum wavelengths of 939 and 752 nm a complete view of saturn s global circulation including the equator at two pressure levels in the tropopause 60 mbar to 250 mbar with the mt filters and in the upper troposphere from 350 mbar to 500 mbar with the cb filter set is presented both zonal wind profiles available at the supplementary material section show the same structure but with significant differences in the peak of the eastward jets and the equatorial region including a region of positive vertical shear symmetrically located around the equator between the 10 c

the south equatorial belt of jupiter ii the onset and development of the 1993 disturbance on april 6 1993 an seb disturbance commenced with a bright white spot at 15 5 s latitude the spot was followed by a dark column lying only 24 from the eastern edge of the great red spot a continuous ccd and photographic survey at visual wavelengths of the event during the four months following the eruption has allowed us to obtain the best imaging records of the evolution of an seb disturbance with a spatial resolution and temporal coverage of unprecedent quality a high resolution zonal wind velocity profile in the 8 s to 25 s latitude range has been obtained tracking the cloud elements pertaining to the sebd and nearby features the sebd central and northern branches developed according to the classical morphology patterns and values of the zonal winds as described in paper i however this sebd event was marked by the unusual proximity of the onset site to the grs and by the interaction of the sebd spots with preexisting features in the strz the new phenomena observed included i a temporal delay in the development of the sebd southern branch spots that moved with lower velocities at about 30 m sec 1 than those observed on the average in other events ii the interaction of a preexisting strz disturbance with the grs and the sebd southern branch features iii the interaction of the features of the central branch with a long lived anticyclonic vortex in the strz the revival of the seb was complete in november 1993 entering the belt during 1994 in an sebd1 phase as described in paper i which was characterized at continuum wavelengths by the formation of a strz belt at 23 5 s and by the presence of synoptic and rapidly changing white spots at 11 5 s this activity formed tilted cloud patterns of turbulence in the northern half of the belt in a region that corresponds to the cyclonic southern half of the strong eastward jetstream at 7 s

ground based imaging of jovian cloud morphologies and motions ii the northern hemisphere from 1975 to 1985 abstract telescopic photographs of jupiter obtained during one jovian year 1975 1985 have been analyzed in order to study the morphology and motions of the great scale cloud systems present in the northern hemisphere during the epoch pre and post voyager flyby spacecraft mission see sanchez lavega and rodrigo 1985 astron astrophys 148 67 78 for a similar work in the southern hemisphere the texture of the north equatorial belt neb was characterized by a variable number of plumes between 11 and 15 a mean of 25 have high albedo heads rifts tilted high albedo clouds crossing the belt in the shear flow sense and turbulent wavy patterns in the northern edge we present interactions between these features as observed in 1985 elongated dark barges and rows of small dark spots were observed near the northern edge of the neb during specific epochs the high albedo north tropical zone ntrz was generally homogeneous from 1977 to 1984 but in 1976 little red spots were observed in its interior and a contrasting visible and red wavelengths narrow belt located in its center was present in 1985 however the most interesting feature in this region was the development of a prominent double disturbance ntrzd during 1975 in the high speed eastward jet at 24 n of which we present a study of its morphology and kinematics pronounced albedo changes were observed in the ntb during the whole period analyzed color contrasts in the ntrz ntb ntz regions were measured in 1985 from broadband relative photometry north of 34 n there were alternating albedo bands characterized by their longitudinal variability by the presence of small light spots in the equatorial side of the eastward jets and by elongated dark sections of the belts on the polar side the zonal wind profile u measured during this jovian year is in good agreement with that obtained from voyager s images and from previous ground based analysis

kinematic history of the meade thrust based on provenance of the bechler conglomerate at red mountain idaho sevier thrust belt with up to 45 km of slip the meade thrust fault in southeastern idaho is one of the major thrusts in the sevier thrust belt yet its age of displacement has remained enigmatic because of the lack of a derivative synorogenic deposit we propose that the synorogenic conglomerate produced by initial meade thrusting crops out on red mountain in southeastern idaho 1 5 km east of the present trace of the meade thrust this conglomerate historically has been considered part of the ephraim formation of the lower cretaceous gannett group but we suggest that it is a conglomeratic facies of the bechler formation localized to the area of red mountain regional stratigraphic considerations and paleontological dates from underlying and overlying strata indicate that the bechler conglomerate facies bcf is aptian in age the bcf is 850 m thick and consists of pebble to boulder conglomerate sandstone and mudrock deposited by fluvial and mass flow processes on medial to distal parts of an alluvial fan paleocurrent data indicate an eastward fan shaped dispersal pattern the bcf contains clasts of micritic limestone chert pebble conglomerate and cherty litharenite that were derived from the ephraim formation in addition the conglomerate contains abundant clasts of ordovician carboniferous and lower mesozoic rocks that crop out on both the meade thrust sheet and the paris thrust sheet 25 30 km to the west the base of the bcf is marked by a local 27 angular unconformity on top of the ephraim formation the bcf contains intraformational progressively rotated angular unconformities internal growth folds and minor dip discontinuities that were produced by simultaneous folding and sediment accumulation on the proximal footwall of the meade thrust provenance modeling indicates that the bcf was derived from mesozoic strata that were exposed along the frontal part of the meade thrust sheet and from paleozoic strata that were coevally exposed in the hindward located paris thrust sheet topography on the paris sheet was rejuvenated as it was carried passively over a major ramp in the meade thrust provenance and structural data are combined to produce an incremental bulk rock retrodeformation of initial meade displacement clasts of jurassic twin creek limestone with pressure solution cleavage in the lower part of the bcf indicate that an episode of layer parallel shortening occurred in the meade hanging wall prior to meade displacement this may have been related to emplacement of the paris thrust sheet the bcf recorded 6 km of initial meade related shortening by thrust slip and fault propagation folding during aptian time illite crystallinity systematic fracture sets in the ephraim formation and bcf finite strain in meade footwall and hanging wall rocks and thermal models by previous workers indicate that the meade thrust sheet ultimately overrode the bcf and other footwall rocks probably during albian cenomanian time the bcf and the meade thrust were folded during slip on thrust faults related to the northern crawford thrust during coniacian time a revised interpretation of gannett group provenance throughout the thrust belt suggests that the ephraim formation was derived from both the paris thrust sheet and an older hindward located thrust sheet the bechler was derived from the meade and paris sheets

fragmentation of a foreland basin in response to out of sequence basement uplifts and structural reactivation el cajon campo del arenal basin nw argentina the style and mechanisms by which a foreland region is incorporated into an orogen depends on the tectonic style effectiveness of uplift and dynamic subsidence classical foreland basin models reflect a self similar propagation of deformation into the foreland in a thin skinned thrust belt setting governed by wedge mechanics thick skinned foreland regions which are characterized by high angle reverse fault bounded basement uplifts and intervening basins however do not fit this idealized model unlike thin skinned tectonic provinces deformation and uplift in these regions may be highly variable in time and space furthermore deformation patterns may be complicated by the presence of preexisting structures particularly those which lie at orientations that enable them to be reactivated and utilized to accommodated deformation under compression the neogene el cajon campo del are nal basin is one of a series of basins located along the eastern margin of the puna plateau within the sierras pampeanas a region that is composed of a thick skinned foreland fragmented by reverse fault bounded basement uplifts that regionally characterize an eastward younging trend this region is superimposed onto the cretaceous salta rift province which provides a series of pre existing structures that may potentially be reactivated the basin is located along the eastern margin of the puna plateau an integral component of the andean orogen which includes several filled uplifted and internally drained cenozoic intraplateau basins structural and sedimentological similarities exist between basins along the margin of the puna and those within it understanding the evolution of foreland basins such as the el cajon campo del arenal basin provides possible mechanisms for the development and incorporation of marginal basins into orogenic belts and in the case of the andean orogen the potential for these basins to be incorporated into the plateau our analysis which integrates seismic sedimentary and thermochronological data characterizes the evolution of this basin and surrounding ranges the appearance in the sedimentary section of a distinct grain age population derived from the basement erosion surface constrains the uplift and erosion of an out of sequence intrabasin high to ca 6 ma the basin fill therefore records an evolution from an undeformed foreland to one that is compartmentalized by basement uplifts and that is incorporated into the greater orogenic structure the data reveal the importance of the reactivation of preexisting structures along the basin margin in creating east dipping structures in a generally west dipping domain these opposing faults on the basin margin consequently caused the out of sequence uplift of the intrabasin range the sierra de quilmes the sierra de quilmes fragments the foreland and because its position is locked by loads to the west and east creates increased deformation within the basin basin fill uplift and incorporation into the orogen unlike basins within the plateau however the el cajon campo del arenal basin has been re excavated and integrated once more into the foreland drainage network

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

dynamics of saturn s great storm of 2010 2011 from cassini iss and rpws saturn s quasi periodic planet encircling storms are the largest convecting cumulus outbursts in the solar system the last eruption was in 1990 sanchez lavega a 1994 chaos 4 341 353 a new eruption started in december 2010 and presented the first ever opportunity to observe such episodic storms from a spacecraft in orbit around saturn fischer g et al 2011 nature 475 75 77 sanchez lavega a et al 2011 nature 475 71 74 fletcher l n et al 2011 science 332 1413 here we analyze images acquired with the cassini imaging science subsystem iss which captured the storm s birth evolution and demise in studying the end of the convective activity we also analyze the saturn electrostatic discharge sed signals detected by the radio and plasma wave science rpws instrument the storm s initial position coincided with that of a previously known feature called the string of pearls sops at 33 n planetocentric latitude intense cumulus convection at the westernmost point of the storm formed a particularly bright head that drifted at 26 9 0 8 m s 1 negative denotes westward motion on january 11 2011 the size of the head was 9200 km and up to 34 000 km in the north south and east west dimensions respectively rpws measurements show that the longitudinal extent of the lightning source expanded with the storm s growth the storm spawned the largest tropospheric vortex ever seen on saturn on january 11 2011 the anticyclone was sized 11 000 km by 12 000 km in the north south and east west directions respectively between january and september 2011 the vortex drifted at an average speed of 8 4 m s 1 we detect anticyclonic circulation in the new vortex the vortex s size gradually decreased after its formation and its central latitude shifted to the north the storm s head moved westward and encountered the new anticyclone from the east in june 2011 after the head vortex collision the rpws instrument detected that the sed activities became intermittent and declined over 40 days until the signals became undetectable in early august in late august the sed radio signals resurged for 9 days the storm left a vast dark area between 32 n and 38 n latitudes surrounded by a highly disturbed region that resembles the mid latitudes of jupiter using iss images we also made cloud tracking wind measurements that reveal differences in the cloud level zonal wind profiles before and after the storm

clastic deposition provenance and sequence of andean thrusting in the frontal eastern cordillera and llanos foreland basin of colombia sedimentological provenance and detrital thermochronological results for basin fill at the modern deformation front of the northern andes 6 n latitude provide a long term eocene to pliocene record of foreland basin sedimentation along the eastern cordillera llanos basin boundary in colombia lithofacies assemblages and paleocurrent orientations in the upward coarsening 5 km thick succession of the nunchia syncline reveal a systematic shift from craton derived shallow marine distal foreland back bulge accumulation in the mirador formation to orogen sourced deltaic and coastal influenced sedimentation of the distal to medial foreland foredeep in the carbonera and leon formations to anastomosing fluvial and distributive braided fluvial megafan systems of the proximal foreland foredeep to wedge top basin in the lower and upper guayabo formation these changes in depositional processes and sediment dispersal are supported by up section variations in detrital zircon u pb and u th he ages that record exhumation of evolving compartmentalized sediment source areas in the eastern cordillera the data are interpreted in terms of a progressive eastward advance in fold and thrust deformation with late eocene oligocene deformation in the axial zone of the eastern cordillera along the western edge of floresta basin soapaga thrust early miocene reactivation inversion of the eastern margin of the mesozoic rift system pajarito and guaicaramo thrusts and middle late miocene propagation of a footwall shortcut fault yopal thrust that created the nunchia syncline in a wedge top piggyback setting of the eastern foothills along the transition from the eastern cordillera to llanos foreland basin collectively the data presented here for the frontal eastern cordillera define a general in sequence pattern of eastward advancing fold and thrust deformation during cenozoic east west shortening in the colombian andes

the 2009 2010 fade of jupiter s south equatorial belt vertical cloud structure models and zonal winds from visible imaging abstract the south equatorial belt seb of jupiter is known to alternate its appearance at visible wavelengths from a classical belt like band most of the time to a short lived zone like aspect which is called a fade of the belt hereafter sebf the albedo change of the seb is due to a change in the structure and properties of the clouds and upper hazes recent works based on infrared observations of the last sebf have shown that the aerosol density below 1 bar increased in parallel with the reflectivity change however the nature of the change in the upper clouds and hazes that produces the visible reflectivity change and whether or not this reflectivity change is accompanied by a change in the winds at the upper cloud level remained unknown in this paper we focus in the near ultraviolet to near infrared reflected sunlight 255 953 nm to address these two issues we characterize the vertical cloud structure above the ammonia condensation level from hubble space telescope images and the zonal wind velocities from long term high quality images coming from the international outer planet watch database both during the seb and sebf phases we show that reflectivity changes do not happen simultaneously in this wavelength range but they start earlier in the most deep sensing filters and end in 2010 with just minor changes in those sensing the highest particle layers our models require a substantial increase of the optical thickness of the cloud deck at 1 0 0 4 bar from cloud 6 2 in july 2009 seb phase to semiinfinite at visual wavelengths in 2010 sebf upper tropospheric particles 240 1400 mbar are also required to become substantially reflectant and their single scattering albedo in the blue changes from 0 0 905 0 005 in november 2009 to 0 0 95 0 01 in june 2010 no significant changes were found in the cloud top heights or in the particle density of the tropospheric haze the disturbance travels from the levels below 3 bar to a level about 400 100 mbar we derive an upward velocity of 0 15 0 05 cm s in agreement with a diffusive process in jupiter s upper troposphere requiring a mean eddy coefficient k 8 105 cm2 s 1 on the other hand cloud tracking on the iopw imaging showed no significant changes in the zonal wind profile between the seb and sebf stages as in other visually huge changes in jupiter s cloud morphology and structure the wind profile remains robust possibly indicating a deeply rooted dynamical regime