a shallow convective model for jupiter s alternating wind bands 1 the dynamics of a thin atmospheric layer 1 340 bar below the cloud tops of jupiter is simulated with a three dimensional nonlinear transformed spectral model the gas is compressible and stratified commensurate with the observed emitted radiation from jupiter s atmosphere the transport of the planet s internal energy in the lower region is taken to be convective but solar heating is not accounted for in qualitative agreement with observations the model produces alternating wind bands and a dominant prograde equatorial jet the zonal wind speed at the equator is within a factor of 2 of the observed values

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

mapping potential vorticity dynamics on jupiter i zonal mean circulation from cassini and voyager 1 data maps of ertel potential vorticity on isentropic surfaces ipv and or quasi geostrophic potential vorticity qgpv are well established in dynamical meteorology as powerful sources of insight into dynamical processes involving balanced flow in the present study we derive maps of zonal mean ipv and qgpv in jupiter s upper troposphere and lower stratosphere by making use of a combination of velocity measurements derived from the tracking of cloud features in images from the voyager 1 and 2 and cassini missions and thermal measurements from the voyager 1 iris and cassini cirs instruments ipv and qgpv are mapped and compared for the entire globe between latitudes 55 profiles of zonally averaged pv show some evidence for a step like pattern suggestive of local pv homogenization separated by strong pv gradients in association with eastward jets though on differing scales in the northern and southern hemispheres the northward gradient of pv ipv or qgpv is found to change sign in several places in each hemisphere even when baroclinic contributions are taken into account the relationship of lateral gradients of ipv and qgpv with the corresponding mean zonal flows indicate that the northern hemisphere may be closer to marginal stability with respect to arnol d s second stability theorem than the southern hemisphere copyright 2006 royal meteorological society

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

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

two classes of volcanic plumes on io abstract comparison of voyager 1 and voyager 2 images of the south polar region of io has revealed that a major volcanic eruption occured there during the period between the two spacecraft encounters an annular deposit 1400 km in diameter formed around the aten patera caldera 311 w 48 s the floor of which changed from orange to red black the characteristics of this eruption are remarkably similar to those described earlier for an eruption centered on surt caldera 338 w 45 n that occured during the same period also at high latitude but in the north both volcanic centers were evidently inactive during the voyager 1 and 2 encounters but were active sometime between the two the geometric and colorimetric characteristics as well as scale of the two annular deposits are virtually identical both resemble the surface features formed by the eruption of pele 255 w 18 s these three very large plume eruptions suggest a class of eruption distinct from that of six smaller plumes observed to be continously active by both voyagers 1 and 2 the smaller plumes of which prometheus is the type example are longer lived deposit bright whitish material erupt at velocities of 0 5 km sec 1 and are concentrated at low latitudes in an equatorial belt around the satellite the very large pele type plumes on the other hand are relatively short lived deposit darker red materials erupt at 1 0 km sec 1 and rather than restricted to a latitudinal band are restricted in longitude from 240 to 360 w both direct thermal infrared temperature measurements and the implied color temperatures for quenched liquid sulfur suggest that hot spot temperatures of 650 k are associated with the large plumes and temperatures 2 in their annuli whereas the large plumes apparently do not two other plumes that occur at either end of the linear feature loki may be intermediate or hybrid between the two classes exhibiting attributes of both additionally loki occurs in the area of overlap in the regional distributions of the two plume classes two distinct volcanic systems involving different volatiles may be responsible for the two classes we propose that the discrete temperatures associated with the two classes are a direct reflection of sulfur s peculiar variation in viscosity with temperature over two temperature ranges 400 to 430 k and 650 k sulfur is a low viscosity fluid orange and black respectively at other temperatures it is either solid or has a high viscosity as a result there will be two zones in io s crust in which liquid sulfur will flow freely a shallow zone of orange sulfur and a deeper zone of black sulfur a low temperature system driven by so 2 heated to 400 to 400 k by the orange sulfur zone seems the best model for the small plumes a system driven by sulfur heated to 650 k by hot or even molten silicates in the black sulfur zone seems the best explanation for the large plume class the large pele type plumes are apparently concentrated in a region of the satellite in which a thinner sulfur rich crust overlies the tidally heated silicate lithosphere so the black sulfur zone may be fairly shallow in this region the prometheus type plumes are possibly confined to the equatorial belt by some process that concentrates so 2 fluid in the equatorial crust

taylor proudman columns in non hydrostatic divergent baroclinic and barotropic flows the taylor proudman theorem states that the velocity of slow steady flow in a rotating incompressible fluid does not change along the direction of the rotation axis this fundamental result has been invoked to explain blocking phenomena observed over topographic features in oceanic and atmospheric flows on earth and atmospheric patterns observed in giant gas planets even in cases where the assumption of incompressibility fails the possible existence of taylor proudman columns is analyzed here for a less restrictive family of non hydrostatic divergent density stratified flows including situations where the stratification gradient and rotation axis are not parallel the results show that taylor proudman like constraints are possible in baroclinic inviscid and viscous nonlinear flows of constant vorticity beltrami flows and low rossby number flows it is found that 1 the baroclinic term is moderated by a factor of the order of the rossby number 2 a conservation law can be found for baroclinic flows and 3 taylor proudman columns will be eroded in viscous flows one particular result stressed in this note is its interpretation in equatorial regions where the rotation axis is perpendicular to the main stratification gradient and it is argued that taylor proudman columns could be difficult to discern with observational parameters from convective cells with only zonal and vertical transport copyright 2009 royal meteorological society

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

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

computer simulations of jupiter s deep internal dynamics help interpret what juno sees we describe computer simulations of thermal convection and magnetic field generation in jupiter s deep interior that is its convective dynamo results from three different simulations highlight the importance of including the dynamics in the very deep interior although much of the convection and field generation seems to be confined to the upper part of the interior a long debated question is to what depth do jupiter s zonal winds extend below its surface our simulations suggest that if global latitudinally banded patterns in jupiter s near surface magnetic and gravity fields were detected by juno nasa s orbiting spacecraft at jupiter bolton s et al 2017 science 356 821 825 they would provide evidence for jupiter s zonal winds extending deep below the surface one of our simulations has also maintained for a couple simulated years a deep axisymmetric inertial wave with properties at the surface that depend on the size of the model s small rocky core if such a wave was detected on jupiter s surface its latitudes and oscillation frequency would provide evidence for the existence and size of jupiter s rocky core

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

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

volcanic activity at tvashtar catena io abstract galileo s solid state imager ssi observed tvashtar catena four times between november 1999 and october 2001 providing a unique look at a distinctive high latitude volcanic complex on io the first observation orbit i25 november 1999 resolved for the first time an active extraterrestrial fissure eruption the brightness temperature was at least 1300 k the second observation orbit i27 february 2000 showed a large 500 km 2 region with many small hot regions of active lava the third observation was taken in conjunction with cassini imaging in december 2000 and showed a pele like annular plume deposit the cassini images revealed an 400 km high pele type plume above tvashtar catena the final galileo ssi observation of tvashtar orbit i32 october 2001 revealed that obvious to ssi activity had ceased although data from galileo s near infrared mapping spectrometer nims indicated that there was still significant thermal emission from the tvashtar region in this paper we primarily analyze the style of eruption during orbit i27 february 2000 comparison with a lava flow cooling model indicates that the behavior of the tvashtar eruption during i27 does not match that of simple advancing lava flows instead it may be an active lava lake or a complex set of lava flows with episodic overlapping eruptions the highest reliable color temperature is 1300 k although higher temperatures cannot be ruled out they do not need to be invoked to fit the observed data the total power output from the active lavas in february 2000 was at least 10 11 w

an objective classification of saturn cloud features from cassini iss images abstract a k means clustering algorithm is applied to cassini imaging science subsystem continuum and methane band images of saturn s northern hemisphere to objectively classify regional albedo features and aid in their dynamical interpretation the procedure is based on a technique applied previously to visible infrared images of earth it provides a new perspective on giant planet cloud morphology and its relationship to the dynamics and a meteorological context for the analysis of other types of simultaneous saturn observations the method identifies 6 clusters that exhibit distinct morphology vertical structure and preferred latitudes of occurrence these correspond to areas dominated by deep convective cells low contrast areas some including thinner and thicker clouds possibly associated with baroclinic instability regions with possible isolated thin cirrus clouds darker areas due to thinner low level clouds or clearer skies due to downwelling or due to absorbing particles and fields of relatively shallow cumulus clouds the spatial associations among these cloud types suggest that dynamically there are three distinct types of latitude bands on saturn deep convectively disturbed latitudes in cyclonic shear regions poleward of the eastward jets convectively suppressed regions near and surrounding the westward jets and baroclinically unstable latitudes near eastward jet cores and in the anti cyclonic regions equatorward of them these are roughly analogous to some of the features of earth s tropics subtropics and midlatitudes respectively this classification may be more useful for dynamics purposes than the traditional belt zone partitioning temporal variations of feature contrast and cluster occurrence suggest that the upper tropospheric haze in the northern hemisphere may have thickened by 2014 the results suggest that routine use of clustering may be a worthwhile complement to many different types of planetary atmospheric data analysis

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

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

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

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

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

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

smart sdb sample specific multiple band ratio technique for satellite derived bathymetry abstract spectrally based retrieval of bathymetry is challenging in inland coastal waters due to variations in factors other than water depth across a water body including bottom type optically significant constituents water surface roughness and others optimal band ratio analysis obra is the most widely used method to deal with these confounding effects to retrieve water depth obra identifies the pair of bands that provides the highest accuracy among all possible pairs when using a log transformed band ratio model however this approach fits a single ratio model to all training samples without fully accounting for the heterogeneity of the aforementioned complicating factors to deal with this problem we introduce a novel method called sample specific multiple band ratio technique for satellite derived bathymetry smart sdb the proposed smart sdb technique partitions the feature space of the spectral data and creates for every subspace a different band ratio model that performs better than the other models within that subspace bathymetry is then predicted based on the closest model s in the feature space by performing a sample specific k nearest neighbor k nn analysis the depth estimates provided by the neighboring models are averaged with weights proportional to their inverse distance in the feature space the proposed method can be used in both inland and coastal waters here we thoroughly examine its effectiveness in the challenging and heterogenous environments of fluvial systems using a wide range of spectral data including radiative transfer simulations an airborne hyperspectral image of the snake river usa and a worldview 3 satellite image of the sarca river italy the results of this study indicate a significant improvement in depth retrieval for estimations based on the smart sdb method relative to standard obra either when a single model or multiple models are employed

galileo observations of volcanic plumes on io abstract io s volcanic plumes erupt in a dazzling variety of sizes shapes colors and opacities in general the plumes fall into two classes representing distinct source gas temperatures most of the galileo imaging observations were of the smaller more numerous prometheus type plumes that are produced when hot flows of silicate lava impinge on volatile surface ices of so2 few detections were made of the giant pele type plumes that vent high temperature sulfur rich gases from the interior of io this was partly because of the insensitivity of galileo s camera to ultraviolet wavelengths both gas and dust spout from plumes of each class favorably located gas plumes were detected during eclipse when io was in jupiter s shadow dense dust columns were imaged in daylight above several prometheus type eruptions reaching heights typically less than 100 km comparisons between eclipse observations sunlit images and the record of surface changes show that these optically thick dust columns are much smaller in stature than the corresponding gas plumes but are adequate to produce the observed surface deposits mie scattering calculations suggest that these conspicuous dust plumes are made up of coarse grained ash particles with radii on the order of 100 nm and total masses on the order of 106 kg per plume long exposure images of thor in sunlight show a faint outer envelope apparently populated by particles small enough to be carried along with the gas flow perhaps formed by condensation of sulfurous snowflakes as suggested by the plasma instrumentation aboard galileo as it flew through thor s plume frank l a paterson w r 2002 j geophys res space phys 107 doi 10 1029 2002ja009240 31 1 if so the total mass of these fine nearly invisible particles may be comparable to the mass of the gas and could account for much of io s rapid resurfacing

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

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

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

temperature and variability of pillan wayland patera and loki patera on io from cassini iss data abstract cassini spacecraft images of io obtained during its flyby of jupiter in late 2000 and early 2001 were used to determine the lava composition and eruption style of three faint hot spots pillan wayland patera and loki patera we found a maximum color temperature of 1130 289 k for pillan and maximum color temperatures of 1297 289 k and 1387 287 k for wayland patera and loki patera respectively these temperatures are suggestive of basaltic lava but an ultramafic composition cannot be ruled out the temperatures with the best signal to noise ratios also suggested basaltic lava and were found to be 780 189 k 1116 250 k and 1017 177 k for pillan wayland patera and loki patera respectively pillan showed constant thermal output within error over three days of observations the data also suggest pillan may be surrounded by topography that blocked emission in the middle of the observation and caused a more dramatic decrease in emission wayland patera s intensity decreased over the three eclipse observations consistent with a cooling lava flow or decreasing effusion rate intensities at loki patera over the course of the observations varied consistent with previous determinations that loki patera is an often quiescent lava lake with periods of overturning fountaining and crustal foundering

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

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

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

surface changes on io during the galileo mission abstract a careful survey of galileo ssi global monitoring images revealed more than 80 apparent surface changes that took place on io during the 5 year period of observation ranging from giant plume deposits to subtle changes in the color or albedo of patera surfaces explosive volcanic activity was discovered at four previously unrecognized centers an unnamed patera to the south of karei that produced a pele sized red ring a patera to the west of zal that produced a small circular bright deposit a large orange ring detected near the north pole of io and a small bright ring near io s south pole only a handful of io s many active volcanoes produced large scale explosive eruptions and several of these erupted repeatedly leaving at least 83 of io s surface unaltered throughout the galileo mission most of the hot spots detected from ssi nims and ground based thermal observations caused no noticeable surface changes greater than 10 km in extent over the five year period surface changes were found at every location where active plumes were identified including acala which was never seen in sunlight and was only detected through auroral emissions during eclipse two types of plumes are distinguished on the basis of the size and color of their deposits confirming post voyager suggestions by mcewen and soderblom icarus 55 1983 191 smaller plumes produce near circular rings typically 150 200 km in radius that are white or yellow in color unless contaminated with silicates and frequently coat their surroundings with frosts of fine grained so2 the larger plumes are much less numerous limited to a half dozen examples and produce oval orange or red sulfur rich rings with maximum radii in the north south direction that are typically in the range from 500 to 550 km both types of plumes can be either episodic or quasi continuous over a five year period repeated eruptions of the smaller so2 rich plumes likely contribute significantly to io s resurfacing rate whereas dust ejection is likely dominated by the tenuous giant plumes both types of plume deposits fade on time scales of months to years through burial and alteration episodic seepages of so2 at haemus montes zal montes dorian montes and the plateau to the north of pillan patera may have been triggered by activity at nearby volcanic centers

jupiter s visible aurora and io footprint images obtained by the galileo spacecraft s solid state imaging ssi system represent the first survey of jupiter s northern auroral emissions at visible wavelengths and on the nightside of the planet these images captured the emissions with unprecedented spatial resolutions down to 26 km pixel 1 four classes of emission were observed 1 a continuous primary arc associated with the middle outer magnetosphere 2 a variable secondary arc associated with the region just beyond io s torus 3 diffuse polar cap emission and 4 a patch and tail associated with the magnetic footprint of io the primary arc emission occurs at an altitude 245 30 km above the 1 bar pressure level its horizontal width is typically a few hundred kilometers and its total optical power output varied between 10 10 and 10 11 w in observations taken months apart the location of the primary arc in planetary coordinates is similar to that on dayside images at other wavelengths and does not vary with local time the morphology of the primary arc is not constant changing from a multiply branched latitudinally distributed pattern after dusk to a single narrow arc before dawn emission from io s ionospheric footprint is distinct from both the primary and secondary arcs measurements of its optical power output ranged from 2 to 7 10 8 w

mapping jupiter s latitudinal bands and great red spot using hst wfpc2 far ultraviolet imaging jupiter s low and mid latitudes are examined using ultraviolet uv images obtained with the hubble space telescope wide field and planetary camera 2 over the period of 1994 1997 effective atmospheric pressures probed by the f160w f218w and f255w are estimated at 100 165 and 370 mbar respectively at low latitudes far ultraviolet images of jupiter taken with the f160w filter reveal bright and dark latitudinal bands at low and mid latitudes these bands were found to be correlated with the zonal winds the bright bands are at latitudes of subsidences and the dark bands at upwellings the sense of this correlation is opposite to that seen in visible images of jupiter where the bright zones are located over upwellings and dark belts over subsidences the locations of the dark bands seen in the f160w images are consistent with enhanced concentrations of nh 3 and or aerosols in the upwellings near the tropopause anticyclonic ovals like the great red spot are regions of upwellings and also appear dark in the f160w images temporal variations were also observed in the contrast of the low latitude bands an increase in the contrast of the low latitude bands appeared to coincide with a visible wavelength broadening of the north equatorial belt that occurred in early to mid 1996 changes at mid southern latitudes were observed in the aftermath of the sl 9 impacts in july 1994

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

zonal jets as transport barriers in planetary atmospheres abstract the connection between transport barriers and potential vorticity pv barriers in pv conserving flows is investigated with a focus on zonal jets in planetary atmospheres a perturbed pv staircase model is used to illustrate important concepts this flow consists of a sequence of narrow eastward and broad westward zonal jets with a staircase pv structure the pv steps are at the latitudes of the cores of the eastward jets numerically simulated solutions to the quasigeostrophic pv conservation equation in a perturbed pv staircase flow are presented these simulations reveal that both eastward and westward zonal jets serve as robust meridional transport barriers the surprise is that westward jets across which the background pv gradient vanishes serve as robust transport barriers a theoretical explanation of the underlying barrier mechanism is provided it is argued that transport barriers near the cores of westward zonal jets across which the background pv gradient is small are found in jupi

the final galileo ssi observations of io orbits g28 i33 abstract we present the observations of io acquired by the solid state imaging ssi experiment during the galileo millennium mission gmm and the strategy we used to plan the exploration of io despite galileo s tight restrictions on data volume and downlink capability and several spacecraft and camera anomalies due to the intense radiation close to jupiter there were many successful ssi observations during gmm four giant high latitude plumes including the largest plume ever observed on io were documented over a period of eight months only faint evidence of such plumes had been seen since the voyager 2 encounter despite monitoring by galileo during the previous five years moreover the source of one of the plumes was tvashtar catena demonstrating that a single site can exhibit remarkably diverse eruption styles from a curtain of lava fountains to extensive surface flows and finally a 400 km high plume over a relatively short period of time 13 months between orbits i25 and g29 despite this substantial activity no evidence of any truly new volcanic center was seen during the six years of galileo observations the recent observations also revealed details of mass wasting processes acting on io slumping and landsliding dominate and occur in close proximity to each other demonstrating spatial variation in material properties over distances of several kilometers however despite the ubiquitous evidence for mass wasting the rate of volcanic resurfacing seems to dominate the floors of paterae in proximity to mountains are generally free of debris finally the highest resolution observations obtained during galileo s final encounters with io provided further evidence for a wide diversity of surface processes at work on io

trace element geochemistry of groundwater from quetta valley western pakistan this manuscript presents major minor and trace elements data for groundwater samples collected from wells tube wells springs and karezes from quetta valley quetta valley in pakistan has frequently experienced shortage of groundwater in recent years the water quality has had a sharp decline at many locations the study of groundwater resources in this valley is an attempt to understand the causes of and sources of contamination at several locations nitrate sulfate arsenic selenium chromium and nickel contamination has been determined the preliminary results indicate that these contaminations apparently result from a combination of rock alteration and mining activity in the area different water sources could have also contributed to the deterioration of the water quality of quetta valley this research provides the basis for future work which will involve detailed hydrological modeling and water quality studies

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

jupiter s atmospheric jet streams extend thousands of kilometres deep the depth to which jupiter s observed east west jet streams extend has been a long standing question resolving this puzzle has been a primary goal for the juno spacecraft which has been in orbit around the gas giant since july 2016 juno s gravitational measurements have revealed that jupiter s gravitational field is north south asymmetric which is a signature of the planet s atmospheric and interior flows here we report that the measured odd gravitational harmonics j 3 j 5 j 7 and j 9 indicate that the observed jet streams as they appear at the cloud level extend down to depths of thousands of kilometres beneath the cloud level probably to the region of magnetic dissipation at a depth of about 3 000 kilometres by inverting the measured gravity values into a wind field we calculate the most likely vertical profile of the deep atmospheric and interior flow and the latitudinal dependence of its depth furthermore the even gravity harmonics j 8 and j 10 resulting from this flow profile also match the measurements when taking into account the contribution of the interior structure these results indicate that the mass of the dynamical atmosphere is about one per cent of jupiter s total mass

longitudinal variation and waves in jupiter s south equatorial wind jet abstract a detailed study of the chevron shaped dark spots on the strong southern equatorial wind jet near 7 5 s planetographic latitude shows variations in velocity with longitude and time the presence of the large anticyclonic south equatorial disturbance sed has a profound effect on the chevron velocity causing slower velocities to its east and increasing with distance from the disturbance the chevrons move with velocities near the maximum wind jet velocity of 140 m s as deduced by the history of velocities at this latitude and the magnitude of the symmetric wind jet near 7 n latitude their repetitive nature is consistent with a gravity inertia wave n 75 100 with phase speed up to 25 m s relative to the local flow but the identity of this wave mode is not well constrained however for the first time high spatial resolution movies from cassini images show that the chevrons oscillate in latitude with a 6 7 0 7 day period this oscillating motion has a wavelength of 20 and a speed of 101 3 m s following a pattern similar to that seen in the rossby wave plumes of the north equatorial zone and possibly reinforced by it all dates show chevron latitude variability but it is unclear if this larger wave is present during other epochs as there are no other suitable time series movies that fully delineate it in the presence of multiple wave modes the difference in dominant cloud appearance between 7 n and 7 5 s is likely due to the presence of the great red spot either through changes in stratification and stability or by acting as a wave boundary

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

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

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

jupiter s unearthly jets a new turbulent model exhibiting statistical steadiness without large scale dissipation abstracta longstanding mystery about jupiter has been the straightness and steadiness of its weather layer jets quite unlike terrestrial strong jets with their characteristic unsteadiness and long wavelength meandering the problem is addressed in two steps the first is to take seriously the classic dowling ingersoll di 1 layer scenario and its supporting observational evidence pointing toward deep massive zonally symmetric zonal jets in the underlying dry convective layer the second is to improve the realism of the model stochastic forcing used to represent the effects of jupiter s moist convection as far as possible within the 1 layer dynamics of the di scenario the real moist convection should be strongest in the belts where the interface to the deep flow is highest and coldest and should generate cyclones as well as anticyclones with the anticyclones systematically stronger the new model forcing reflects these insights also it acts quasi frictionally on large scales to produce statisti

spatial organization and time dependence of jupiter s tropospheric temperatures 1980 1993 the spatial organization and time dependence of jupiter s temperatures near 250 millibar pressure were measured through a jovian year by imaging thermal emission at 18 micrometers the temperature field is influenced by seasonal radiative forcing and its banded organization is closely correlated with the visible cloud field evidence was found for a quasi periodic oscillation of temperatures in the equatorial zone a correlation between tropospheric and stratospheric waves in the north equatorial belt and slowly moving thermal features in the north and south equatorial belts there appears to be no common relation between temporal changes of temperature and changes in the visual albedo of the various axisymmetric bands

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

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

constraints on saturn s tropospheric general circulation from cassini iss images abstract an automated cloud tracking algorithm is applied to cassini imaging science subsystem high resolution apoapsis images of saturn from 2005 and 2007 and moderate resolution images from 2011 and 2012 to define the near global distribution of zonal winds and eddy momentum fluxes at the middle troposphere cloud level and in the upper troposphere haze improvements in the tracking algorithm combined with the greater feature contrast in the northern hemisphere during the approach to spring equinox allow for better rejection of erroneous wind vectors a more objective assessment at any latitude of the quality of the mean zonal wind and a population of winds comparable in size to that available for the much higher contrast atmosphere of jupiter zonal winds at cloud level changed little between 2005 and 2007 at all latitudes sampled upper troposphere zonal winds derived from methane band images are 10 m s 1 weaker than cloud level winds in the cores of eastward jets and 5 m s 1 stronger on either side of the jet core i e eastward jets appear to broaden with increasing altitude in westward jet regions winds are approximately the same at both altitudes lateral eddy momentum fluxes are directed into eastward jet cores including the strong equatorial jet and away from westward jet cores and weaken with increasing altitude on the flanks of the eastward jets consistent with the upward broadening of these jets the conversion rate of eddy to mean zonal kinetic energy at the visible cloud level is larger in eastward jet regions 5 2 10 5 m 2 s 3 and smaller in westward jet regions 1 6 10 5 m 2 s 3 than the global mean value 4 1 10 5 m 2 s 3 overall the results are consistent with theories that suggest that the jets and the overturning meridional circulation at cloud level on saturn are maintained at least in part by eddies due to instabilities of the large scale flow near and or below the cloud level

observations and temperatures of io s pele patera from cassini and galileo spacecraft images abstract pele has been the most intense high temperature hotspot on io to be continuously active during the galileo monitoring from 1996 2001 a suite of characteristics suggests that pele is an active lava lake inside a volcanic depression in 2000 2001 pele was observed by two spacecraft cassini and galileo the cassini observations revealed that pele is variable in activity over timescales of minutes typical of active lava lakes in hawaii and ethiopia these observations also revealed that the short wavelength thermal emission from pele decreases with rotation of io by a factor significantly greater than the cosine of the emission angle and that the color temperature becomes more variable and hotter at high emission angles this behavior suggests that a significant portion of the visible thermal emission from pele comes from lava fountains within a topographically confined lava body high spatial resolution nightside images from a galileo flyby in october 2001 revealed a large relatively cool

influence of ocean surface conditions on atmospheric vertical thermodynamic structure and deep convection abstract the authors analyze the influence of sea surface temperature sst and surface wind divergence on atmospheric thermodynamic structure and the resulting effects on the occurrence of deep convection using national meteorological center radiosonde data and international satellite cloud climatology program data for july 1983 july 1985 the onset of deep convection requires not only the existence of positive convective available potential energy cape but also an unstable planetary boundary layer pbl a stable pbl is observed to suppress deep convection even when cape is positive variations of sst have a major effect on cape but surface wind divergence can also affect deep convection by changing the lapse rate in the lower troposphere and humidity in the pbl specifically when sst 28 c cape is always positive and surface wind divergence does not qualitatively change the buoyancy profile above the pbl strong surface wind divergence however stabilizes the pbl so as to suppress the initiation

jupiter s great red spot fine scale matches of model vorticity patterns to prevailing cloud patterns abstract we report on a set of six new matches between fine scale features in the vorticity field of a three dimensional 3d primitive equation finite difference model of jupiter s great red spot that includes no clouds or cloud physics and quasi permanent structures in reflected visible band images of the clouds these add to similar success by cho et al cho j de la torre juarez m ingersoll a p dritschel d g 2001 j geophys res 106 5099 5106 who earlier captured four characteristic features of the grs also reproduced here using a 3d quasi geostrophic cloud free contour dynamics model in that study and this the key enabling model attribute is sufficient horizontal resolution rather than the moist convective and cloud microphysics processes often required to match the patterns of clouds in terrestrial hurricanes the only significant feature that these dry models do not capture is the episodic moist convective plumes seen in the northwest quadrant adjacent to the grs we initialize with jupiter s averaged zonal winds plus an approximately balanced smooth 3d ellipsoidal anticyclone the threshold horizontal grid resolution to obtain the fine scale matches is approximately y ld 0 15 where y 300 km is the meridional grid spacing and ld 2000 km the rossby deformation length for models with this or finer horizontal resolution the best correspondence with observations is reached after about six vortex turnaround times from initialization 30 earth days but good facsimiles of nearly all the studied features appear after only 1 5 turnaround times 7 8 days we conclude that in images of jupiter it is not accurate to associate clouds with upward motion since these dry models reproduce the observed cloud patterns without this association and indeed the synoptic scale vertical motions in the model as well as those deduced from observations do not at all correspond to the observed cloud patterns instead jupiter s cloud top patterns indicate the effects of local shear in the manner of passive tracer fields as a corollary the water clouds on jupiter which lie unseen below its visible clouds are the only ones on the planet likely to correlate with upwelling in the manner that clouds do on earth the next step is to extend studies such as this past the reflected visible band for example to include the grs s 5 m emission bright collar which may require the inclusion of cloud physics to enable the successful simulation of large voids

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

the dusk flank of jupiter s magnetosphere limited single spacecraft observations of jupiter s magnetopause have been used to infer that the boundary moves inward or outward in response to variations in the dynamic pressure of the solar wind at earth multiple spacecraft observations have been implemented to understand the physics of how this motion occurs because they can provide a snapshot of a transient event in progress here we present a set of nearly simultaneous two point measurements of the jovian magnetopause at a time when the jovian magnetopause was in a state of transition from a relatively larger to a relatively smaller size in response to an increase in solar wind pressure the response of jupiter s magnetopause is very similar to that of the earth confirming that the understanding built on studies of the earth s magnetosphere is valid the data also reveal evidence for a well developed boundary layer just inside the magnetopause

the first close up images of jupiter s polar regions results from the juno mission junocam instrument during juno s first perijove encounter the junocam instrument acquired the first images of jupiter s polar regions at 50 70 km spatial scale at low emission angles poleward of 64 68 planetocentric latitude where jupiter s east west banded structure breaks down several types of discrete features appear on a darker background cyclonic oval features are clustered near both poles other oval shaped features are also present ranging in size from 2000 km down to junocam s resolution limits the largest and brightest features often have chaotic shapes two narrow linear features in the north associated with an overlying haze feature traverse tens of degrees of longitude junocam also detected an optically thin cloud or haze layer past the northern nightside terminator estimated to be 58 21 km approximately three scale heights above the main cloud deck junocam will acquire polar images on every perijove allowing us to track the state and evolution of longer lived features

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

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

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

clusters of cyclones encircling jupiter s poles the familiar axisymmetric zones and belts that characterize jupiter s weather system at lower latitudes give way to pervasive cyclonic activity at higher latitudes two dimensional turbulence in combination with the coriolis effect that is the large meridionally varying coriolis force on the giant planets of the solar system produces alternating zonal flows the zonal flows weaken with rising latitude so that a transition between equatorial jets and polar turbulence on jupiter can occur simulations with shallow water models of giant planets support this transition by producing both alternating flows near the equator and circumpolar cyclones near the poles jovian polar regions are not visible from earth owing to jupiter s low axial tilt and were poorly characterized by previous missions because the trajectories of these missions did not venture far from jupiter s equatorial plane here we report that visible and infrared images obtained from above each pole by the juno spacecraft during its first five orbits reveal persistent polygonal patterns of large cyclones in the north eight circumpolar cyclones are observed about a single polar cyclone in the south one polar cyclone is encircled by five circumpolar cyclones cyclonic circulation is established via time lapse imagery obtained over intervals ranging from 20 minutes to 4 hours although migration of cyclones towards the pole might be expected as a consequence of the coriolis effect by which cyclonic vortices naturally drift towards the rotational pole the configuration of the cyclones is without precedent on other planets including saturn s polar hexagonal features the manner in which the cyclones persist without merging and the process by which they evolve to their current configuration are unknown

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

the vertical profile of radar reflectivity of convective cells a strong indicator of storm intensity and lightning probability abstract reflectivity data from doppler radars are used to construct vertical profiles of radar reflectivity vprr of convective cells in mesoscale convective systems mcss in three different environmental regimes the national center for atmospheric research cp 3 and cp 4 radars are used to calculate median vprr for mcss in the oklahoma kansas preliminary regional experiment for storm central in 1985 the national oceanic and atmospheric administration tropical ocean global atmosphere radar in darwin australia is used to calculate vprr for mcss observed both in oceanic monsoon regimes and in continental break period regimes during the wet seasons of 1987 88 and 1988 89 the midlatitude and tropical continental vprrs both exhibit maximum reflectivity somewhat above the surface and have a gradual decrease in reflectivity with height above the freezing level in sharp contrast the tropical oceanic profile has a maximum reflectivity at the lowest level and a very rapid decrease in reflectivity with he

origin of jupiter s cloud level zonal winds remains a puzzle even after juno how far jupiter s cloud level zonal winds penetrate into its interior a question related to the origin of the winds has long been a major puzzle about jupiter there exist two different views the shallow scenario in which the cloud level winds are confined within the thin weather layer at cloud top and the deep scenario in which the cloud level winds manifest thermal convection in the deep interior we interpret using two different models corresponding to the two scenarios the high precision measurements of jupiter s equatorially antisymmetric gravitational field by the juno spacecraft we demonstrate based on the thermal gravitational wind equation that both the shallow and deep cloud level winds models are capable of explaining the measured odd gravitational coefficients within the measured uncertainties reflecting the nonunique nature of the gravity inverse problem we conclude that the high precision juno gravity measurements cannot provide an answer to the long standing question about the origin of jupiter s cloud level zonal winds

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