foraminiferal assemblages from bottom sediments at marian cove south shetland islands west antarctica abstract foraminiferal samples were taken from bottom sediments at marian cove west antarctica in order to determine the depth zonation and foraminiferal species composition benthic foraminiferal communities are mainly composed of calcareous agglutinated and mixed associations the fisher diversity of the total assemblage groups is close to 6 0 the dominance diversity patterns are characterized by low dominance and high diversity three zones are recognized at marian cove with depth boundaries at 22 and 65 5 m areas shallower than 22 m are nearly devoid of any toraminifera calcareous forms and or calcareous forms mixed with agglutinated forms are relatively abundant between 22 and 65 5 m while agglutinated forms dominate below 65 5 m

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

jupiter s great red spot as a shallow water system most current models of jupiter s great red spot grs are cast in terms of a two layer model where a thin upper weather layer which contains the vortex overlies a much deeper layer which is meant to represent the neutrally stratified deep atmosphere any motions in the deep layer are assumed to be zonal and steady this two layer model is dynamically equivalent to a one layer model with meridionally varying solid bottom topography called the reduced gravity model specifying the motions or lack thereof in the lower layer of the two layer model is equivalent to specifying the bottom topography and hence the far field potential vorticity in the reduced gravity model current models of the grs start by guessing the deep motions and then proceed to study vortices using the implied bottom topography here using the grs cloud top velocity data we derive the bottom topography up to a constant that depends on the unknown radius of deformation or equivalently the product of the reduced gravity and the mean thickness of the upper layer the bottom topography is inferred from three quantities derived from the velocity data bernoulli streamfunction kinetic energy per unit mass and absolute vorticity all of which are functions only of horizontal position in the reference frame of the vortex far from the vortex potential vorticity versus latitude is calculated from the observed cloud top zonal velocity and the derived bottom topography the results show that the deep atmosphere is in differential motion and that the far field potential vorticity gradient changes sign at several latitudes numerical shallow water experiments are performed using both the derived bottom topography and the bottom topographies prescribed by current models the results of three published studies are reproduced in our numerical experiments each of these models is successful in maintaining a long lived isolated vortex but only the present model yields absolute vorticity profiles along streamlines that agree with those observed for the grs by dowling and ingersoll in all the models large vortices form by merging with smaller vortices in the present observationally based model and in one other published model the smaller vortices arise spontaneously because the observed cloud top zonal velocity profile is unstable these two models require an additional momentum source to maintain the upper layer zonal velocity profile in the other two models the bottom topography stabilizes the zonal velocity profile if dissipation is present the latter two models require an additional source of smaller vortices to maintain the larger one a crucial unanswered question for the present model and for jupiter itself is how the cloud top zonal velocity profile is maintained in its present unstable state

color and the vertical structure in jupiter s belts zones and weather systems abstract radiative transfer analysis was performed with data taken by the galileo spacecraft solid state imager ssi during its nominal mission december 1995 to december 1997 the objective is to use the methane band 727 and 889 nm and color 410 and 756 nm sensitivities to identify the vertical position of cloud absorption that leads to coloration earlier work banfield et al 1998 icarus 135 230 250 with only the near ir continuum and methane band images yielded information about the vertical distribution of cloud scatterers but no information on the wavelength dependence of cloud absorption the new analysis employs the same parameter retrieval algorithm but adds the 410 nm wavelength under the assumption that the 410 nm absorption by cloud particles is indicative of spectrally broad blue absorption the new channel gives color information the primary color difference between the dark north equatorial belt neb and the brighter equatorial zone ez appears to be in the tropospheric haze layer s 410 nm single scattering albedo this layer extends through the stably stratified region approximately from 200 to 800 mbars the base of the haze layer is slightly deeper in the neb by about 200 mbars than in the ez and a variable thickness white cloud layer at the base of the haze exists in both regions but is about five times optically thicker in the ez within the ez slight color variation is seen with latitude again due to 410 nm single scattering albedo variation in the haze layer anomalous regions such as the great red spot and a 5 m hot spot are modeled showing additional variations in the structure and color of the tropospheric haze deeper clouds with pressures of 1 7 bars are seen in occasional clearings but their opacity and color are not well constrained by the data

mid infrared mapping of jupiter s temperatures aerosol opacity and chemical distributions with irtf texes abstract global maps of jupiter s atmospheric temperatures gaseous composition and aerosol opacity are derived from a programme of 5 20 m mid infrared spectroscopic observations using the texas echelon cross echelle spectrograph texes on nasa s infrared telescope facility irtf image cubes from december 2014 in eight spectral channels with spectral resolutions of r 2000 12 000 and spatial resolutions of 2 4 latitude are inverted to generate 3d maps of tropospheric and stratospheric temperatures 2d maps of upper tropospheric aerosols phosphine and ammonia and 2d maps of stratospheric ethane and acetylene the results are compared to a re analysis of cassini composite infrared spectrometer cirs observations acquired during cassini s closest approach to jupiter in december 2000 demonstrating that this new archive of ground based mapping spectroscopy can match and surpass the quality of previous investigations and will permit future studies of jupiter s evolving atmosphere the visibility of cool zones and warm belts varies from channel to channel suggesting complex vertical variations from the radiatively controlled upper troposphere to the convective mid troposphere we identify mid infrared signatures of jupiter s 5 m hotspots via simultaneous m n and q band observations which are interpreted as temperature and ammonia variations in the northern equatorial zone and on the edge of the north equatorial belt neb equatorial plumes enriched in nh3 gas are located south east of nh3 desiccated hotspots on the edge of the neb comparison of the hotspot locations in several channels across the 5 20 m range indicate that these anomalous regions tilt westward with altitude aerosols and ph3 are both enriched at the equator but are not co located with the nh3 plumes the equatorial temperature minimum and ph3 aerosol maxima have varied in amplitude over time possibly as a result of periodic equatorial brightenings and the fresh updrafts of disequilibrium material temperate mid latitudes display a correlation between mid ir aerosol opacity and the white albedo features in visible light i e zones we find hemispheric asymmetries in the distribution of tropospheric ph3 stratospheric hydrocarbons and the 2d wind field estimated via the thermal wind equation that suggest a differing efficiency of mechanical forcing e g vertical mixing and wave propagation between the two hemispheres that we argue is driven by dynamics rather than jupiter s small seasonal cycle jupiter s stratosphere is notably warmer at northern mid latitudes than in the south in both 2000 and 2014 although the latter can be largely attributed to strong thermal wave activity near 30 n that dominates the 2014 stratospheric maps and may be responsible for elevated c2h2 in the northern hemisphere a vertically variable pattern of temperature and windshear minima and maxima associated with jupiter s quasi quadrennial oscillation qqo is observed at the equator in both datasets although the contrasts were more subdued in 2014 large scale equator to pole gradients in ethane and acetylene are superimposed on top of the mid latitude mechanically driven maxima with c2h2 decreasing from equator to pole and c2h6 showing a polar enhancement consistent with a radiatively controlled circulation from low to high latitudes cold polar vortices beyond 60 latitude can be identified in the upper tropospheric and lower stratospheric temperature maps suggesting enhanced radiative cooling from polar aerosols finally compositional mapping of the great red spot confirms the local enhancements in ph3 and aerosols the north south asymmetry in nh3 gas and the presence of a warm southern periphery that have been noted by previous authors

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

foraminiferal assemblages and caco3 dissolution since the last deglaciation in the maxwell bay king george island antarctica abstract three sediment cores a10 01 02 and 08 from the maxwell bay king george island antarctica were quantitatively analyzed for foraminiferal fauna planktonic foraminifera of three cores are rare due to the special antarctica environment benthic foraminifera is mainly composed of globocassidulina biora globocassidulina crassa rossensis cassidulinoides parkerianus and miliammina arenacea g biora and g crassa rossensis show high percentages in the shallower core a10 08 while m arenacea displays obviously high percentage in deeper core a10 02 the lower parts of the cores have a lower abundance of foraminifera while the upper parts have a relatively higher abundance the down core variations of benthic foraminifera reflect the contrast of surface water environment between the last deglaciation and post glacial during the last deglaciation lower parts of the cores the lower abundant foraminifera was consistent with the lower toc which reflected that the extensive sea ice prevented the production of primary organisms and therefore lower flux of organic particles was delivered to the sea floor abundant foraminifera together with higher toc in the upper parts of the cores suggested a higher primary productivity after the glaciation the shallowest water depth core a10 08 45 m displayed a better carbonate preservation than the other two cores a10 01 and 02 from the depths of 85 and 105 m respectively the disparity in carbonate dissolution reflected the remarkable shallow lysocline and carbonate compensation depth ccd in the antarctic area and also reflected significant variations in water properties even within such a difference only about 60 m in water depth down core variations of benthic foraminifera dissolution index bdi and caco 3 content indicated the existence of stronger carbonate dissolution in the upper parts than those in the lower parts of the cores the down core variations of carbonate dissolution suggested changes of water properties linked to the shallow ccd in this area it was supposed that the less influence of the saline shelf water during the last deglaciation enhanced the carbonate preservation with the sea level increasing and retreat of the coastal ice after the glacial erosive water masses and the higher co 2 accumulated by the increased flux of organic material led to severe dissolution of caco 3 and foraminiferal shells in the sediment

jupiter cloud composition stratification convection and wave motion a view from new horizons several observations of jupiter s atmosphere made by instruments on the new horizons spacecraft have implications for the stability and dynamics of jupiter s weather layer mesoscale waves first seen by voyager have been observed at a spatial resolution of 11 to 45 kilometers these waves have a 300 kilometer wavelength and phase velocities greater than the local zonal flow by 100 meters per second much higher than predicted by models additionally infrared spectral measurements over five successive jupiter rotations at spatial resolutions of 200 to 140 kilometers have shown the development of transient ammonia ice clouds lifetimes of 40 hours or less in regions of strong atmospheric upwelling both of these phenomena serve as probes of atmospheric dynamics below the visible cloud tops

glaciomarine sedimentation and palaeo glacial setting of maxwell bay and its tributary embayment marian cove south shetland islands west antarctica abstract high resolution 3 5 khz and multi channel seismic profiles and piston cores were collected from maxwell bay and its tributary embayment marian cove in the south shetland islands antarctica during the korea antarctic research program 1992 93 and 1995 96 to elucidate the glaciomarine sedimentation processes and recent glacial history of the area seismic data from maxwell bay reveal a rugged bay margin and flattened basin floor covered with well stratified hemipelagic muds on the base of slope acoustically transparent debris flows occur indicating downslope resedimentation of glaciomarine sediments despite the subpolar and ice proximal settings of marian cove the seafloor is highly rugged with a thin sediment drape suggesting that much of the area has been recently eroded by glaciers sediment cores from the cove penetrated three distinct fining upward lithofacies 1 basal till in the lower part of the core accumulated just seaward of the grounding line of the tidewater glacier 2 interlaminated sand and mud in the middle part deposited in ice proximal zone by a combination of episodic subglacial meltwater inflow and iceberg dumping and 3 pebbly mud in the upper part deposited in ice distal zone by both surface meltwater plume and ice rafting from the glacier front a reconstruction of the glacial history of these areas since the late glacial maximum shows an ice sheet filling maxwell bay in late wisconsin time and grounding of the tidewater glacier in marian cove until about 1300 yr bp

active geologic processes in barrow canyon northeast chukchi sea abstract circulation patterns on the shelf and at the shelf break appear to dominate the barrow canyon system the canyon s shelf portion underlies and is maintained by the alaska coastal current a c c which flows northeastward along the coast toward the northeast corner of the broad chukchi sea offshelf and onshelf advective processes are indicated by oceanographic measurements of other workers these advective processes may play an important role in the production of bedforms that are found near the canyon head as well as in processes of erosion or non deposition in the deeper canyon itself coarse sediments recovered from the canyon axis at 400 to 570 m indicate that there is presently significant flow along the canyon the canyon hooks left at a point north of point barrow where the a c c loses its coastal constriction the left hook as well as preferential west wall erosion continues down to the abyssal plain of the canada basin at 3800 m a possible explanation for the preferential west wall erosion along the canyon at least for the upper few hundred meters is that the occasional upwelling events which cause nutrient rich water to flow along the west wall would in turn cause larger populations of burrowing organisms to live there than on the east wall and that these organisms cause high rates of bioerosion this hypothesis assumes that the dominant factor in the canyon s erosion is biological activity not current velocity sedimentary bedforms consisting of waves and furrows are formed in soft mud in a region on the shelf west of the canyon head their presence there perhaps reflects a the supply of fine suspended sediments delivered by the a c c from sources to the south probably the yukon and other rivers draining northwestern alaska and b the westward transport of these suspended sediments by the prevailing beaufort gyre which flows along the outer shelf

keck adaptive optics images of jupiter s north polar cap and northern red oval abstract we present observations at near infrared wavelengths 1 5 m of jupiter s north polar region and northern red oval nn lrs 1 the observations were taken with the near infrared camera nirc2 coupled to the adaptive optics system on the 10 m w m keck telescope on ut 21 august 2010 at 5 m jupiter s disk reveals considerable structure including small bright rings which appear to surround all small vortices it is striking though that no such ring is seen around the northern red oval in de pater et al 2010a icarus 210 742 762 we showed that such rings also exist around all small vortices in jupiter s southern hemisphere and are absent around the great red spot and red oval ba we show here that the vertical structure and extent of the northern red oval is very similar to that of jupiter s red oval ba these new observations of the northern red oval therefore support the idea of a dichotomy between small and large anticyclones in which ovals larger than about two rossby deformation radii do not have 5 m bright rings in de pater et al 2010a icarus 210 742 762 we explained this difference in terms of the secondary circulations within the vortices we further compare the brightness distribution of our new 5 m images with previously published radio observations of jupiter highlighting the depletion of nh 3 gas over areas that are bright at 5 m

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

jupiter s equatorial plumes and hot spots spectral mapping from gemini texes and juno mwr we present multi wavelength measurements of the thermal chemical and cloud contrasts associated with the visibly dark formations also known as 5 m hot spots and intervening bright plumes on the boundary between jupiter s equatorial zone ez and north equatorial belt neb observations made by the texes 5 20 m spectrometer at the gemini north telescope in march 2017 reveal the upper tropospheric properties of 12 hot spots which are directly compared to measurements by juno using the microwave radiometer mwr jiram at 5 m and juno cam visible images mwr and thermal infrared spectroscopic results are consistent near 0 7 bar mid infrared derived aerosol opacity is consistent with that inferred from visible albedo and 5 m opacity maps aerosol contrasts the defining characteristics of the cloudy plumes and aerosol depleted hot spots are not a good proxy for microwave brightness the hot spots are neither uniformly warmer nor ammonia depleted compared to their surroundings at p 10 bars suggesting that the hot spot plume wave is a relatively shallow feature plain language summary to date our only direct measurement of jupiter s gaseous composition came from the descent of the galileo probe in 1995 however the results from galileo appeared to be biased due to the unusual meteorological conditions of its entry location a dark cloud free region just north of the equator known as a hot spot one of the aims of nasa s juno mission was to place the findings of the galileo probe into broader con text which requires a detailed characterisation of these equatorial hot spots and their neighbouring plumes we combine a data from juno microwave observations sounding conditions below the clouds and visible infrared observations revealing variations in cloud opacity with b observations from amateur observers to track the hot spots over time and c observations from the texes infrared spectrometer mounted on the gemini north telescope the latter provides the highest resolution thermal maps of jupiter s tropics ever obtained and reveals contrasts within and between the individual hot spots and plumes we find that the hot spots are distinguishable from their surroundings for relatively shallow pressures but that the deep measurements from juno and galileo are probably more representative of jupiter s north equatorial belt than previously thought

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

why is the h3 hot spot above jupiter s great red spot so hot recent observations of jupiter s great red spot indicate that the thermosphere above the storm is hotter than its surroundings by more than 700 k possible suggested sources for this heating have t

climatic control of sedimentation in bays and fjords of the northern antarctic peninsula abstract the northern antarctic peninsula is dominated by strong climatic gradients which are locally enhanced by subsidiary orographic and topographic effects these gradients are reflected in the sediments of the bays and fjords of the region the climate of the south shetland islands is relatively warm with high levels of precipitation this leads to a temperate glacial setting in which many glaciers terminate on land and bay waters which are turbid with terrigenous debris sediments which consist of terrigenous muds and sands with a low ice rafted debris ird content are relatively thick 70 m and have now filled in and almost completely mask the underlying basement topography the palmer archipelago is colder than the south shetland islands and is the wettest area of the antarctic it is heavily glaciated and all major glaciers are grounded below sea level only rarely have sediment plumes been seen the sediments which are primarily terrigenous muds and sands with a variable ird component are thin maximum 40 m but are ponding in every available bathymetric depression the pristine nature of the ice visible above sea level indicates that terrigenous debris is entering the bays from below sea level sediment gravity flows are important in redistributing sediment the danco coast lies within the precipitation shadow of the graham land plateau its climate is slightly colder and is the driest in the study area with less than half of the precipitation of the palmer archipelago nevertheless it is also heavily glaciated with few exceptions sediments here are diatomaceous muds and oozes they are very thin and drape across the rugged basement topography rather than ponding in lows sediment gravity flow deposits are rare these observations indicate a lower rate of production of terrigenous sediment here a consequence of the drier climatic setting

galileo photopolarimeter radiometer observations of jupiter and the galilean satellites photopolarimeter radiometer ppr maps of daytime temperatures on ganymede at a resolution of 220 kilometers show the expected anticorrelation with albedo but morning temperatures were about 10 kelvin warmer than expected europa had a subsolar temperature of 128 kelvin and a lower effective thermal inertia than either ganymede or callisto and io9s night side was cooler than predicted by recent models perhaps requiring revision of heat flow estimates the lowest 250 millibar temperatures in the great red spot grs generally corresponded to the visually darkest regions temperatures remained cold north of the grs but they rose by as much as 6 kelvin to the south over the 2800 kilometer ppr resolution a visually bright region northwest of the grs was also relatively cold it is likely that nh3 clouds affected the determination of the 500 millibar temperature field which appears qualitatively different

sediment transport processes on an active submarine fault escarpment gulf of corinth greece abstract sediment transport processes on the escarpment of a listric fault in the tectonically active and terrigenous sediment dominated corinth graben in greece are studied using 3 5 khz and airgun profiles and sidescan sonar images the whole of the slope area is affected by gravitational mass movements slumps debris mud flows and liquified and turbidity flows in canyon fan systems large volumes of sediment are transported through slumping debris mud and turbidity flows into the basin here they build coalescing fans which consist of intercalations of debris flow deposits and turbidites in delta front slope fan apron systems sediments are transported radially downslope through slumping debris mud flows liquified flows and high density turbidity flows into the basin where they build coalescing fan aprons these consist of massive homogenized deposits fluxoturbidites in shelf slope systems retrogressive rotational slumping is the dominant instability feature however due to the sharp increase in the slope gradient caused by the slumping debris and turbidity flows are triggered the major factors responsible for triggering gravitational mass movements in the region are earthquakes high sedimentation rates off the river mouths and heavy rainfalls and high seas these mass movements appear to occur at least once every 2 yrs as indicated by the failure of submarine cables

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

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

thermal structure and composition of jupiter s great red spot from high resolution thermal imaging abstract thermal ir imaging from space borne and ground based observatories was used to investigate the temperature composition and aerosol structure of jupiter s great red spot grs and its temporal variability between 1995 and 2008 an elliptical warm core extending over 8 of longitude and 3 of latitude was observed within the cold anticyclonic vortex at 21 s the warm airmass is co located with the deepest red coloration of the grs interior the maximum contrast between the core and the coldest regions of the grs was 3 0 3 5 k in the north south direction at 400 mbar atmospheric pressure although the warmer temperatures are present throughout the 150 500 mbar range the resulting thermal gradients cause counter rotating flow in the grs center to decay with altitude into the lower stratosphere the elliptical warm airmass was too small to be observed in irtf imaging prior to 2006 but was present throughout the 2006 2008 period in vlt subaru and gemini imaging spatially resolved maps of mid ir tropospheric aerosol opacity revealed a well defined lane of depleted aerosols around the grs periphery and a correlation with visibly dark jovian clouds and bright 4 8 m emission ammonia showed a similar but broader ring of depletion encircling the grs this narrow lane of subsidence keeps red aerosols physically separate from white aerosols external to the grs the visibility of the 4 8 m bright periphery varies with the mid ir aerosol opacity of the upper troposphere compositional maps of ammonia phosphine and para h 2 within the grs interior all exhibit north south asymmetries with evidence for higher concentrations north of the warm central core and the strongest depletions in a symmetric arc near the southern periphery small scale enhancements in temperature nh 3 and aerosol opacity associated with localized convection are observed within the generally warm and aerosol free south equatorial belt seb northwest of the grs the extent of 4 8 m emission from the seb varied as a part of the 2007 global upheaval though changes during this period were restricted to pressures greater than 500 mbar finally a region of enhanced temperatures extended southwest of the grs during the survey restricted to the 100 400 mbar range and with no counterpart in visible imaging or compositional mapping the warm airmass was perturbed by frequent encounters with the cold airmass of oval ba but no internal thermal or compositional effects were noted in either vortex during the close encounters

correlation of nearshore ice movement with seabed ice gouges near barrow alaska nearshore patterns of ice motion near barrow alaska were monitored between 1973 and 1979 with a sea ice radar system side scan sonar surveys of the seafloor were made at the same location during the summers of 1977 and 1978 the two data sets provide information on ice motion ice gouging and the rate and character of seabed deformation by ice four ice stages open water freeze up winter and breakup can be defined on the basis of the frequency and patterns of ice motion and ice cover processes as recorded by the radar system in all four ice stages the dominant ice motion was nearly parallel to the coast side scan sonar surveys show that the principal ice gouge directions nearshore were at a high angle to the coast and to the predominant direction of ice drift in both years gouge density was greatest in a narrow zone centered about the 10 m isobath which reflects the distribution of deep ice keels and the pattern of reworking of the seafloor by waves and currents we believe the majority of observed gouges were formed by keels of multiyear ice floes during an event that occurred in july 1975 2 years before the first seabed survey persistence of the gouge pattern from 1975 until 1977 is attributed to persistence of the ice cover and limited reworking by waves and currents or additional gouging the observed decrease in gouge density between 1977 and 1978 is attributed to 1 seafloor reworking and gouge infilling by storms and 2 the absence of ice conditions that were conducive to creating fresh gouges

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

benthic foraminiferal assemblages from the eastern weddell sea between 68 and 73 s distribution ecology and fossilization potential surface sediment samples taken with a vented box corer from the eastern weddell sea on four profiles perpendicular to the continental margin have been investigated for their benthic foraminiferal content the live fauna was differentiated from empty tests comprising the foraminiferal death assemblage based on the dead assemblages potential fossil assemblages were calculated to facilitate the analogy with late neogene core material five distinct live assemblages inhabit the continental margin today six dead assemblages and five potential fossil assemblages respectively correspond to these biocoenoses a predominantly calcareous live fauna dominated by trifarina angulosa is correlated with strong bottom currents and sandy sediments at the shelf break and on the uppermost continental slope below this on the upper slope down to 2000 m water depth the predominantly calcareous bulimina aculeata assemblage coincides with the core of warm 0 c weddell deep water and with fine and more organic rich sediments these calcareous live assemblages completely change composition during early diagenesis because of calcite dissolution within the uppermost sediment which depends largely on the grain size distribution of the sediment and the fluxes of organic matter therefore a still calcareous t angulosa dominated fossil assemblage indicates the sandy substrates on the shelf break and the upper slope whereas the deeper slope with hemipelagic calm sedimentation and with high fluxes of organic matter is indicated by martinottiella nodulosa the characteristic arenaceous fossil remnant of the former predominantly calcareous live b aculeata fauna on a continental terrace between 2500 and 3500 m water depth cribrostomoides subglobosus dominates the live fauna but because of rapid disintegration of the empty tests of this agglutinated species a predominantly calcareous fauna characterized by oridorsalis umbonatus and epistominella exigua comprises the dead assemblage and the potential fossil assemblage respectively on the lower continental slope between the carbonate lysocline 3500 m and the carbonate compensation depth 4000 m tests of nuttallides umbonifer are the characteristic dead and potential fossil remnants of a former predominantly arenaceous live fauna which is associated with the lower part of the antarctic bottom water aabw this corroborates earlier investigations suggesting a relationship between the carbonate corrosiveness of water masses and the distribution of n umbonifer this is important for inferring paleo routes and estimates of paleo production rates of aabw during the neogene

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

multiple meltwater discharge and ice rafting events recorded in the deglacial sediments along the beaufort margin arctic ocean abstract the first regional model for the deglacial history of the beaufort margin slope in the western arctic is presented the conceptual model was developed using new high resolution chirp seismic reflection multibeam bathymetry and sediment core data acquired along the margin this synthesis provides important constraints on sediment source and dispersal patterns for the last deglaciation the continental slope from barrow canyon to the mackenzie trough is characterized by thick holocene sediments mostly sourced from barrow canyon and continental discharge this acoustically transparent fine grained unit overlies acoustically laminated sediments sourced from the mackenzie river and ice rafting the deglacial history of the margin from mackenzie trough to the amundsen gulf is characterized by many ice rafting and meltwater discharge events ice rafted debris layers were deposited around 14 6 ka and 14 1 ka and likely document enhanced ice shedding events from the amundsen and m clure ice streams as they retreated there are three inferred meltwater discharge events all sourced from the mackenzie region the oldest discharge event had two phases one sometime between 14 5 ka and 14 2 ka and another between 14 0 ka and 13 0 ka this discharge deposited finely laminated sediments more than 7 m thick sourced from proglacial lakes in the area following this was a flood event starting at 12 94 ka which generated high amplitude reflectors deposited coarse debris and caused a lowering in the 18o record this is possibly a major outburst flood from glacial lake agassiz with an additional component of agassiz meltwater that was diverted from its southern drainage pathway down the mississippi to the gulf of mexico finally a third discharge event was initiated by 11 3 ka which deposited coarse laminated sediments focused in the mackenzie trough timing of these second and third events correlates with the onset of the younger dryas cold period and the preboreal oscillation event respectively suggesting that fresh water discharge may have reached a tipping point leading to those climate events

fresh ammonia ice clouds in jupiter i spectroscopic identification spatial distribution and dynamical implications we report the first spectroscopic detection of discrete ammonia ice clouds in the atmosphere of jupiter as discovered utilizing the galileo near infrared mapping spectrometer nims spectrally identifiable ammonia clouds siacs cover less than 1 of the globe as measured in complete global imagery obtained in september 1996 during galileo s second orbit more than half of the most spectrally prominent siacs reside within a small latitudinal band extending from 2 to 7 n latitude just south of the 5 m hot spots the most prominent of these are spatially correlated with nearby 5 m bright hot spots lying 1 5 3 0 of latitude to the north they reside over a small range of relative longitudes on the eastward side of hot spots about 37 of the longitudinal distance to the next hot spot to the east this strong correlation between the positions of hot spots and the most prominent equatorial siacs suggests that they are linked by a common planetary wave good agreement is demonstrated between regions of condensation predicted by the rossby wave model of a j friedson and g s orton 1999 bull am astron assoc31 1155 1156 and the observed longitudinal positions of fresh ammonia clouds relative to 5 m hot spots consistency is also demonstrated between 1 the lifetime of particles as determined by the wave phase speed and cloud width and 2 the sedimentation time for 10 m radius particles consistent with previously reported ammonia particle size by t y brooke et al 1998 icarus136 1 13 a young age two days for most siac cloud particles is indicated to the south the most prominent siacs are located to the northwest of the great red spot in a region where a westward flow of jovian air diverted approximately 10 of latitude northward by the great red spot encounters a large eastward flow siacs have been observed repeatedly by nims at this location during galileo s first four years in jupiter orbit it is speculated that due to the three dimensional interactions of these flows relatively large amounts of ammonia gas are steadily transported from the sub cloud troposphere below the 600 mbar level to the high troposphere nearly continuously forming fresh ammonia ice clouds to the northwest of the great red spot

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

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

carbonate dissolution and abyssal hydrography in the atlantic ocean abstract surface sediment samples from two regions in the eastern atlantic angola basin and cape verde basin and two regions in the western atlantic brazil basin and vema channel were examined to evaluate the relationship among carbonate dissolution abyssal hydrography and carbonate chemistry of the water column at each of these locations the position of the lysocline was determined carbonate saturation 1 was calculated and major deep water mass boundaries were identified as previously observed the correlation among these variables is strikingly different between the eastern and western atlantic in the vema channel and the brazil basin there is a first order correlation among the position of the lysocline the benthic thermocline aabw nadw boundary and the transition from saturation to undersaturation with respect to carbonate this relationship breaks down in the eastern atlantic where there is no noticeable benthic thermocline and the lysocline occurs significantly deeper than the saturation undersaturation transition

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

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