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Voyager IRIS data reveal strong similarities among a broad range of features which differ considerably in visual appearance. The atmosphere above anticyclonic features, including the major white ovals, the Great Red Spot, and a zone, are cold relative to the immediate surroundings in the upper troposphere and tropopause region. These results are consistent with upwelling and divergence in this part of the atmosphere. A hot spot and a barge, which are localized cyclonic features, are found to be warm relative to their surroundings, implying subsidence with accompanying convergence. In all cases, the thermal wind shear associated with the features indicates a decay of the vorticity with height in the upper troposphere and lower stratosphere. Vertical velocities inferred from the observed temperature perturbations imply an upper limit of vertical mixing times near the tropopause of approximately 20 years. Temperatures in the upper stratosphere above the anticyclonic features show considerable variation, but in most cases are found to be relatively warm.

A new parameterisation is described that predicts the temperature perturbations due to sub-grid scale orographic gravity waves in the atmosphere of the 19 level HadAM3 version of the United Kingdom Met Office Unified Model. The explicit calculation of the wave phase allows the sign of the temperature perturbation to be predicted. The scheme is used to create orographic clouds, including cirrus, that were previously absent in model simulations. A novel approach to the validation of this parameterisation makes use of both satellite observations of a case study, and a simulation in which the Unified Model is nudged towards ERA-40 assimilated winds, temperatures and humidities. It is demonstrated that this approach offers a feasible way of introducing large scale orographic cirrus clouds into GCMs.

The Defense Nuclear Agency is sponsoring a broad-based research program on the dynamics and phenomenology of high altitude nuclear explosions (HANEs). An important goal of this research is to understand and model the late time nuclear environment; specifically, the intense field-aligned striations which are produced. These striations are regions of high electron density and are of military significance because they can adversely impact communication and surveillance systems. Of particular interest to DNA is the development of a model which characterizes the power spectral density of nuclear striations: the outer scale, the freezing scale, the inner scale, and the associated power law exponents between these scale sizes. This information provides a description of the late time nuclear environment which can be used in propagation codes relevant to military systems. This document describes 3D plasma cloud dynamics model of Drake et al. (1988) which is applied to barium clouds and to nuclear striations. Quantitative estimates of the critical scale size for marginal stability are presented. The implications of these results regarding the 'freezing' of plasma striations are discussed.

The Defense Nuclear Agency is sponsoring a broad-based research program on the dynamics and phenomenology of high altitude nuclear explosions (HANEs). An important goal of this research is to understand and model the late time nuclear environment; specifically, the intense field-aligned striations which are produced. These striations are regions of high electron density and are of military significance because they can adversely impact communication and surveillance systems. Of particular interest to DNA is the development of a model which characterizes the power spectral density of nuclear striations: the outer scale, the freezing scale, the inner scale, and the associated power law exponents between these scale sizes. This information provides a description of the late time nuclear environment which can be used in propagation codes relevant to military systems. This document describes 3D plasma cloud dynamics model of Drake et al. (1988) which is applied to barium clouds and to nuclear striations. Quantitative estimates of the critical scale size for marginal stability are presented. The implications of these results regarding the 'freezing' of plasma striations are discussed.

We describe simulations of the response of a gaseous disc to an active spiral potential. The potential is derived from an N-body calculation and leads to a multi-armed time-evolving pattern. The gas forms long spiral arms typical of grand design galaxies, although the spiral pattern is asymmetric. The primary difference from a grand-design spiral galaxy, which has a consistent 2/4-armed pattern, is that instead of passing through the spiral arms, gas generally falls into a developing potential minimum and is released only when the local minimum dissolves. In this case, the densest gas is coincident with the spiral potential, rather than offset as in the grand-design spirals. We would there fore expect no offset between the spiral shock and star formation, and no obvious co-rotation radius. Spurs which occur in grand-design spirals when large clumps are sheared off leaving the spiral arms, are rare in the active, time-evolving spiral reported here. Instead, large branches are formed from spiral arms when the underlying spiral potential is dissolving due to the N-body dynamics. We find that the molecular cloud mass spectrum for the active potential is similar to that for clouds in grand design calculations, depending primarily on the ambient pressure rather than the nature of the potential. The largest molecular clouds occur when spiral arms collide, rather than by agglomeration within a spiral arm.

We derive general expressions for the LMC velocity field which we fit to kinematical data for 1041 carbon stars. We demonstrate that all previous studies of LMC kinematics have made unnecessary over-simplifications that have led to incorrect estimates of important structural parameters. We compile and improve LMC proper motion estimates to support our analysis. We find that the kinematically determined position angle of the line of nodes is 129.9 +/- 6.0 deg. The LMC inclination changes at a rate di/dt = -103 +/- 61 deg/Gyr, a result of precession and nutation induced by Milky Way tidal torques. The LMC rotation curve V(R) has amplitude 49.8 +/- 15.9 km/s, 40% lower than what has previously (and incorrectly) been inferred from e.g. HI. The dynamical center of the carbon stars is consistent with the center of the bar and the center of the outer isophotes, but not with the HI kinematical center. The enclosed mass inside 8.9 kpc is (8.7 +/- 4.3) x 10^9 M_sun, more than half of which is due to a dark halo. The LMC has a larger vertical thickness than has traditionally been believed. Its V/sigma is less than the value for the Milky Way thick disk. We discuss the implications for the LMC self-lensing optical depth. We determine the LMC velocity and orbit in the Galactocentric rest frame and find it to be consistent with the range of velocities that has been predicted by models for the Magellanic Stream. The Milky Way dark halo must have mass >4.3 x 10^{11} M_sun and extent >39 kpc for the LMC to be bound. We predict the LMC proper motion velocity field, and discuss techniques for kinematical distance estimation. [ABRIDGED]

We present an empirical dynamical model of the local interstellar medium based on 270 radial-velocity measurements for 157 sight lines toward nearby stars. Physical-parameter measurements (i.e., temperature, turbulent velocity, depletions) are available for 90 components, or one-third of the sample, enabling initial characterizations of the physical properties of LISM clouds. The model includes 15 warm clouds located within 15 pc of the Sun, each with a different velocity vector. We derive projected morphologies of all clouds and estimate the volume filling factor of warm partially ionized material in the LISM to be between ~5.5% and 19%. Relative velocities of potentially interacting clouds are often supersonic, consistent with heating, turbulent, and metal-depletion properties. Cloud-cloud collisions may be responsible for the filamentary morphologies found in ~1/3 of LISM clouds, the distribution of clouds along the boundaries of the two nearest clouds (LIC and G), the detailed shape and heating of the Mic Cloud, the location of nearby radio scintillation screens, and the location of a LISM cold cloud. Contrary to previous claims, the Sun appears to be located in the transition zone between the LIC and G Clouds.

The Oort Cloud Comets (OCCs), exemplified by the Great Comet of 1997 (Hale-Bopp), are occasional visitors from the heatless periphery of the solar system. Previous works hypothesized that a great majority of OCCs must physically disrupt after one or two passages through the inner solar system, where strong thermal gradients can cause phase transitions or volatile pressure buildup. Here we study the fate of small debris particles produced by OCC disruptions to determine whether the imprints of a hypothetical population of OCC meteoroids can be found in the existing meteor radar data. We find that OCC particles with diameters D 1 um have a very low Earth-impact probability. The intermediate particle sizes, D=100 um, represent a sweet spot. About 1% of these particles orbitally evolve by Poynting-Robertson drag to reach orbits with semimajor axis a=1 AU. They are expected to produce meteors with radiants near the apex of the Earth's orbital motion. We find that the model distributions of their impact speeds and orbits provide a good match to radar observations of apex meteors, except for the eccentricity distribution, which is more skewed toward e=1 in our model. Finally, we propose an explanation for the long-standing problem in meteor science related to the relative strength of apex and helion/antihelion sources. As we show in detail, the observed trend, with the apex meteors being more prominent in observations of highly sensitive radars, can be related to orbital dynamics of particles released on the long-period orbits.

The evolution of synoptic-scale dynamics associated with a middle and upper tropospheric cloud event that occurred on 26 November 1991 is examined. The case under consideration occurred during the FIRE CIRRUS-II Intensive Field Observing Period held in Coffeyville, KS during Nov. and Dec., 1991. Using data from the wind profiler demonstration network and a temporally and spatially augmented radiosonde array, emphasis is given to explaining the evolution of the kinematically-derived ageostrophic vertical circulations and correlating the circulation with the forcing of an extensively sampled cloud field. This is facilitated by decomposing the horizontal divergence into its component parts through a natural coordinate representation of the flow. Ageostrophic vertical circulations are inferred and compared to the circulation forcing arising from geostrophic confluence and shearing deformation derived from the Sawyer-Eliassen Equation. It is found that a thermodynamically indirect vertical circulation existed in association with a jet streak exit region. The circulation was displaced to the cyclonic side of the jet axis due to the orientation of the jet exit between a deepening diffluent trough and building ridge. The cloud line formed in the ascending branch of the vertical circulation with the most concentrated cloud development occurring in conjunction with the maximum large-scale vertical motion. The relationship between the large scale dynamics and the parameterization of middle and upper tropospheric clouds in large-scale models is discussed and an example of ice water contents derived from a parameterization forced by the diagnosed vertical motions and observed water vapor contents is presented.

The study described in this report extends our knowledge of single bubble dynamics to multibubble dynamics. Within the restriction of characteristic bubble size small compared to interbubble distance, the dynamics of a bubble cloud is investigated. Dynamic effects in absence as well as in presence of heat and mass transfer at the bubble wall are considered. The matched asymptotic expansion method is used and enables derivation of differential equations for the bubble shape components at the various orders of approximation. These were solved numerically and the pressure field was deduced. When, during a significant portion of the imposed pressure field history, the liquid is superheated or gas supersaturated, heat and mass transfer at the interface interfere with the dynamics of the bubble growth or oscillations. In that case, the dynamic equation of a bubble in the cloud is coupled to the heat or mass transfer equation by the value of the partial pressures of the liquid vapor and noncondensible gas inside the bubble which are then transfer dependent. This problem is solved when the liquid properties or conditions are such that the variation of the liquid temperature of the gas concentration in the liquid occurs primarily in a thin boundary layer at the bubble wall. In that case an integral equation relates bubble dynamics and heat or mass transfer at the bubble interface.

The radiation field over a broken stratocumulus cloud deck is simulated by the Monte Carlo method. We conducted four experiments to investigate the main factor for the observed shortwave reflectively over the FIRE flight 2 leg 5, in which reflectivity decreases almost linearly from the cloud center to cloud edge while the cloud top height and the brightness temperature remain almost constant through out the clouds. From our results, the geometry effect, however, did not contribute significantly to what has been observed. We found that the variation of the volume extinction coefficient as a function of its relative position in the cloud affects the reflectivity efficiently. Additional check of the brightness temperature of each experiment also confirms this conclusion. The cloud microphysical data showed some interesting features. We found that the cloud droplet spectrum is nearly log-normal distributed when the clouds were solid. However, whether the shift of cloud droplet spectrum toward the larger end is not certain. The decrease of number density from cloud center to cloud edges seems to have more significant effects on the optical properties.

As the 7 December 2007 equinox of Uranus approached, ring and atmosphere observers produced a substantial collection of observations using the 10-m Keck telescope and the Hubble Space Telescope. Those spanning the period from 7 June 2007 through 9 September 2007 we used to identify and track cloud features, determine atmospheric motions, characterize cloud morphology and dynamics, and define changes in atmospheric band structure. We confirmed the existence of the suspected northern hemisphere prograde jet, locating its peak near 58 N, and extended wind speed measurements to 73 N. For 28 cloud features we obtained extremely high wind-speed accuracy through extended tracking times. The new results confirm a small N-S asymmetry in the zonal wind profile, and the lack of any change in the southern hemisphere between 1986 (near solstice) and 2007 (near equinox) suggests that the asymmetry may be permanent rather than seasonally reversing. In the 2007 images we found two prominent groups of discrete cloud features with very long lifetimes. The one near 30 S has departed from its previous oscillatory motion and started a significant northward drift, accompanied by substantial morphological changes. The complex of features near 30 N remained at a nearly fixed latitude, while exhibiting some characteristics of a dark spot accompanied by bright companion features. Smaller and less stable features were used to track cloud motions at other latitudes, some of which lasted over many planet rotations, though many could not be tracked beyond a single transit. A bright band has developed near 45 N, while the bright band near 45 S has begun to decline, both events in agreement with the idea that the asymmetric band structure of Uranus is a delayed response to solar forcing, but with a surprisingly short delay of only a few years.

The massive infrared dark cloud G0.253+0.016 projected 45pc from the Galactic centre contains ~10^5Msun of dense gas whilst being mostly devoid of observed star-formation tracers. To scrutinise the physical properties, dynamics and structure of this cloud with reference to its star-forming potential, we have carried out a concerted SMA and IRAM 30m study of this cloud in dust continuum, CO isotopologues, shock tracing molecules, as well as H$_2$CO to trace the gas temperature. We detect and characterise the dust cores within G0.253+0.016 at ~1.3 mm and find that the kinetic temperature of the gas is >320K on size-scales of ~0.15 pc. Analysis of the position-velocity diagrams of our observed lines show broad linewidths and strong shock emission in the south of the cloud, indicating that G0.253+0.016 is colliding with another cloud at v(LSR)~70 km/s. We confirm via an analysis of the observed dynamics in the CMZ that it is an elongated structure, orientated with Sgr B2 closer to the Sun than Sgr A*, however our results suggest that the actual geometry may be more complex than an elliptical ring. We find that the column density PDF of G0.253+0.016 is log-normal with no discernible power-law tail, consistent with little star formation, and that its width can be explained in the framework of theory predicting the density structure of clouds created by supersonic, magnetised turbulence. We also present the delta-variance spectrum of this region, and show it is consistent with that expected for clouds with no star formation. Using G0.253+0.016 as a test-bed of the conditions required for star formation in a different physical environment to that of nearby clouds, we also conclude that there is not one column density threshold for star formation, but instead this value is dependant on the local physical conditions. [Abbrv.]

The dynamic properties of comets entering the planetary zone from the Oort cloud are discussed. Even a very slight influence of the large planets can trigger stochastic cometary dynamics. Multiple interactions of comets with the large planets produce diffusion of the parameters of cometary orbits and a mean increase in the semi-major axis of comets. Comets are lifted towards the Oort cloud, where collisions with stars begin to play a substantial role. The transport of comets differs greatly from the customary law of diffusion and noticeably alter cometary distribution.

In the age of cloud computing, cloud users with a limited amount of storage can outsource their data to remote servers. The cloud servers, in lieu of monetary benefits, offer retrievability of their clients' data at any point of time. Secure cloud storage protocols ensure the integrity of the outsourced data that can be dynamic (or static) in nature depending on whether the client can (or cannot) update the uploaded data as needed. In this work, we explore the possibility of constructing a secure cloud storage for dynamic data by leveraging the idea of secure network coding. Specifically, we fail to provide a general construction of an efficient secure cloud storage protocol for dynamic data from an arbitrary secure network coding protocol. However, we show that some of the secure network coding schemes with some required properties can be used to construct secure cloud storage protocols for dynamic data, and we indeed construct a publicly verifiable secure cloud storage protocol based on a secure network coding protocol. In a publicly verifiable setting, it is desirable that a third party auditor gains no knowledge about the actual content of the client's data which may be sensitive. We extend our scheme in order to provide privacy-preserving audits. Furthermore, we extend our scheme in order to offer anonymity of a user updating shared data in an enterprise setting. We also modify an existing secure cloud storage protocol for dynamic data in order to support privacy-preserving audits. We compare the performance of our secure cloud storage protocol with that of other secure cloud storage schemes. Finally, we provide another construction of a secure cloud storage protocol that is specialized for append-only data and that overcomes some of the limitations of our earlier scheme.

The Oort Cloud Comets (OCCs), exemplified by the Great Comet of 1997 (Hale-Bopp), are occasional visitors from the heatless periphery of the solar system. Previous works hypothesized that a great majority of OCCs must physically disrupt after one or two passages through the inner solar system, where strong thermal gradients can cause phase transitions or volatile pressure buildup. Here we study the fate of small debris particles produced by OCC disruptions to determine whether the imprints of a hypothetical population of OCC meteoroids can be found in the existing meteor radar data. We find that OCC particles with diameters D < or approx. 10 microns are blown out from the solar system by radiation pressure, while those with D > or approx. 1 mm have a very low Earth-impact probability. The intermediate particle sizes, D approx. 100 microns represent a sweet spot. About 1% of these particles orbitally evolve by Poynting-Robertson drag to reach orbits with semimajor axis a approx. 1 AU. They are expected to produce meteors with radiants near the apex of the Earth s orbital motion. We find that the model distributions of their impact speeds and orbits provide a good match to radar observations of apex meteors, except for the eccentricity distribution, which is more skewed toward e approx. 1 in our model. Finally, we propose an explanation for the long-standing problem in meteor science related to the relative strength of apex and helion/antihelion sources. As we show in detail, the observed trend, with the apex meteors being more prominent in observations of highly sensitive radars, can be related to orbital dynamics of particles released on the long-period orbits.

We utilize the extensive datasets available for the Perseus molecular cloud to analyze the relationship between the kinematics of small-scale dense cores and the larger structures in which they are embedded. The kinematic measures presented here can be used in conjunction with those discussed in our previous work as strong observational constraints that numerical simulations (or analytic models) of star formation should match. We find that dense cores have small motions with respect to the 13CO gas, about one third of the 13CO velocity dispersion along the same line of sight. Within each extinction region, the core-to-core velocity dispersion is about half of the total (13CO) velocity dispersion seen in the region. Large-scale velocity gradients account for roughly half of the total velocity dispersion in each region, similar to what is predicted from large-scale turbulent modes following a power spectrum of P(k) ~ k^{-4}.

Measurements of the thermospheric neutral wind and ionospheric drift made at Eglin AFB, Florida and Kwajalein Atoll are discussed. The neutral wind measurements at Eglin had little variation over a period of four years for moderate magnetic activity (Kp 4); the ionospheric drifts are small. Evidence is presented that indicates that increased magnetic activity has a significant effect on the neutral wind magnitude and direction at this midlatitude station. The neutral wind at dusk near the equator is generally small although in one case out of seven it was significantly larger. It is described how observations of large barium releases can be used to infer the degree of electrodynamic coupling of ion clouds to the background ionosphere. Evidence is presented that indicates that large barium releases are coupled to the conjugate ionosphere at midlatitudes.

Simulations are performed using a multiple temperature gas model to investigate translational non-equilibrium effects in a rapid expansion of a high temperature argon gas cloud into a rarefied atmosphere. A set of continuum conservation equations based on kinetic theory, which includes anisotropic forms for the temperature, pressure and speed ratio, are solved numerically using a flux splitting scheme for the inviscid fluxes and a central difference scheme for the viscous fluxes in a time accurate manner. Results obtained for the initial expansion of the spherical gas cloud from a high density source condition show that translational non-equilibrium exists in the shock front region which propagates into the ambient atmosphere. For a lower density source condition, translational non-equilibrium not only exists in the shock front but also in the inner gas cloud region where the temperature normal to the radial direction freezes at a value just below the initial source temperature.

This is one of a series of animations that were produced to be part of the narrated video shown in the HoloGlobe exhibit at the Smithsonian Museum of Natural History and the Earth Today exhibit at the Smithsonian Air and Space Museum. This particular animation was not used in the final video. Note: Cloud dynamics and motion over the eastern hemisphere of the Earth as measured by geosynchronous weather satellites. Data Collected: Unknown. Animator: Jim Strong (NASA/GSFC). Scientist: Tom Watters (Smithsonian/Air and Space). Platforms/Sensors/Data Sets: FY-2, GMS-5, Meteosat.

The project was concerned with dynamics in telecommunication networks, with principal focus on peer-to-peer dissemination systems. A first line of work was to develop the theory for a fluid-PDE model for content evolution in peer-to-peer networks. We rigorously proved its mathematical relationship with queueing systems. We also included heterogeneity in the model for peer access bandwidth. The PDE dynamics was analyzed comprehensively froma control-theoretic perspective. A second line of contributions referred to the relationship between the microscopic mechanisms for piece exchange in peer-to-peer, and the resulting bandwidth allocation. We studied a proportional reciprocity mechanism which allows for a mathematical prediction of performance, and studied how to approximate this allocation through neighbor selection, using the Gibbs sampler. A third line concerns dissemination in wireless ad-hoc networks, in which P2P communication bandwidths are influenced by location. Optimal sharing schemes tailored to this setting were analyzed.

Significant acomplishments, current focus of work, plans for FY-80, and recommendations for new research are outlined for 36 research projects proposed for technical monitoring by the Atmospheric Sciences Division at Marshall Space Flight Center. Topics of the investigations, which were reviewed at a two-day meeting, relate to cloud physics, atmospheric electricity, and mesoscale/storm dynamics.

Significant acomplishments, current focus of work, plans for FY-80, and recommendations for new research are outlined for 36 research projects proposed for technical monitoring by the Atmospheric Sciences Division at Marshall Space Flight Center. Topics of the investigations, which were reviewed at a two-day meeting, relate to cloud physics, atmospheric electricity, and mesoscale/storm dynamics.

243 pages ; 22 cm

This item represents a case in PACER, the U.S. Government's website for federal case data. If you wish to see the entire case, please consult PACER directly.

This item represents a case in PACER, the U.S. Government's website for federal case data. If you wish to see the entire case, please consult PACER directly.

The diversity of albedos and surface colors on observed Kuiper Belt and Inner Oort Cloud objects remains to be explained in terms of competition between primordial intrinsic versus exogenic drivers of surface and near-surface evolution. Earlier models have attempted without success to attribute this diversity to the relations between surface radiolysis from cosmic ray irradiation and gardening by meteoritic impacts. A more flexible approach considers the different depth-dependent radiation profiles produced by low-energy plasma, suprathermal, and maximally penetrating charged particles of the heliospheric and local interstellar radiation environment. Generally red objects of the dynamically cold (low inclination, circular orbit) Classical Kuiper Belt might be accounted for from erosive effects of plasma ions and reddening effects of high energy cosmic ray ions, while suprathermal keV-MeV ions could alternatively produce more color neutral surfaces. The deepest layer of more pristine ice can be brought to the surface from meter to kilometer depths by larger impact events and potentially by cryovolcanic activity. The bright surfaces of some larger objects, e.g. Eris, suggest ongoing resurfacing activity. Cycles of atmospheric formation and surface freezeout can further account for temporal variation as observed on Pluto. The diversity of causative processes must therefore be understood to account for observationally apparent diversities of the object surfaces.

The CubeSat Constellation Cloud Winds (C3Winds) is a NASA Earth Venture Instrument (EV-I) concept with the primary objective to better understand mesoscale dynamics and their structures in severe weather systems. With potential catastrophic damage and loss of life, strong extratropical and tropical cyclones (ETCs and TCs) have profound three-dimensional impacts on the atmospheric dynamic and thermodynamic structures, producing complex cloud precipitation patterns, strong low-level winds, extensive tropopause folds, and intense stratosphere-troposphere exchange. Employing a compact, stereo IR-visible imaging technique from two formation-flying CubeSats, C3Winds seeks to measure and map high-resolution (2 km) cloud motion vectors (CMVs) and cloud geometric height (CGH) accurately by tracking cloud features within 5-15 min. Complementary to lidar wind observations from space, the high-resolution wind fields from C3Winds will allow detailed investigations on strong low-level wind formation in an occluded ETC development, structural variations of TC inner-core rotation, and impacts of tropopause folding events on tropospheric ozone and air quality. Together with scatterometer ocean surface winds, C3Winds will provide a more comprehensive depiction of atmosphere-boundary-layer dynamics and interactive processes. Built upon mature imaging technologies and long history of stereoscopic remote sensing, C3Winds provides an innovative, cost-effective solution to global wind observations with potential of increased diurnal sampling via CubeSat constellation.

The CubeSat Constellation Cloud Winds (C3Winds) is a NASA Earth Venture Instrument (EV-I) concept with the primary objective to better understand mesoscale dynamics and their structures in severe weather systems. With potential catastrophic damage and loss of life, strong extratropical and tropical cyclones (ETCs and TCs) have profound three-dimensional impacts on the atmospheric dynamic and thermodynamic structures, producing complex cloud precipitation patterns, strong low-level winds, extensive tropopause folds, and intense stratosphere-troposphere exchange. Employing a compact, stereo IR-visible imaging technique from two formation-flying CubeSats, C3Winds seeks to measure and map high-resolution (2 km) cloud motion vectors (CMVs) and cloud geometric height (CGH) accurately by tracking cloud features within 5-15 min. Complementary to lidar wind observations from space, the high-resolution wind fields from C3Winds will allow detailed investigations on strong low-level wind formation in an occluded ETC development, structural variations of TC inner-core rotation, and impacts of tropopause folding events on tropospheric ozone and air quality. Together with scatterometer ocean surface winds, C3Winds will provide a more comprehensive depiction of atmosphere-boundary-layer dynamics and interactive processes. Built upon mature imaging technologies and long history of stereoscopic remote sensing, C3Winds provides an innovative, cost-effective solution to global wind observations with potential of increased diurnal sampling via CubeSat constellation.

The CubeSat Constellation Cloud Winds (C3Winds) is a NASA Earth Venture Instrument (EV-I) concept with the primary objective to better understand mesoscale dynamics and their structures in severe weather systems. With potential catastrophic damage and loss of life, strong extratropical and tropical cyclones (ETCs and TCs) have profound three-dimensional impacts on the atmospheric dynamic and thermodynamic structures, producing complex cloud precipitation patterns, strong low-level winds, extensive tropopause folds, and intense stratosphere-troposphere exchange. Employing a compact, stereo IR-visible imaging technique from two formation-flying CubeSats, C3Winds seeks to measure and map high-resolution (2 km) cloud motion vectors (CMVs) and cloud geometric height (CGH) accurately by tracking cloud features within 5-15 min. Complementary to lidar wind observations from space, the high-resolution wind fields from C3Winds will allow detailed investigations on strong low-level wind formation in an occluded ETC development, structural variations of TC inner-core rotation, and impacts of tropopause folding events on tropospheric ozone and air quality. Together with scatterometer ocean surface winds, C3Winds will provide a more comprehensive depiction of atmosphere-boundary-layer dynamics and interactive processes. Built upon mature imaging technologies and long history of stereoscopic remote sensing, C3Winds provides an innovative, cost-effective solution to global wind observations with potential of increased diurnal sampling via CubeSat constellation.

We present a combined analysis of the kinematics of the Large Magellanic Cloud through its HI gas, carbon stars, and red supergiant stars. After correcting the line-of-sight velocities for the recent accurate measurement of the LMC's space motion, we find that each kinematic tracer clearly defines a flat rotation curve with similar shape but different amplitude for each tracer: 61 km/s for the carbon stars, 80 km/s for the HI, and 107 km/s for the red supergiants. Previously identified tidal HI features are seen to harbor numerous carbon stars, with the tidally disturbed stars comprising 7-15% of the total sample. This discovery implies that we cannot depend on the carbon star sample alone to construct a reliable model of the LMC's gravitational potential. We also find red supergiants with peculiar kinematics, but their association with tidal features is unclear, and may instead be interacting with supergiant HI shell SGS4. In addition, although the local velocity dispersion of the red supergiants is small, ~8 km/s, their velocity dispersion about the carbon star rotation solution is 17 km/s, equal to the velocity dispersion of the carbon stars themselves. We thus appear to be witnessing the tidal heating of the LMC's stellar disk.

We present a detailed analysis of the evolution of impurity screening cloud in the Resonant Level Model (RLM) followed by quenches of system parameters. The considered quenches are either local or found to be effectively local. The screening cloud is characterized by impurity-bath correlators and by the entanglement of a block centered around the impurity with the rest of the system. We consider several local quench protocols, such as, quenches from initially decoupled to coupled impurity, quenches between different finite couplings of the impurity, and `detuning quenches' involving changing the onsite impurity potential away from or to the chemical potential of the bath. The relevant correlators and the entanglement display versions of the `light-cone' effect, since the information about the quench travels through the bath at finite speed. At long times (`inside' the light cone), the impurity screening cloud relaxes exponentially to the final equilibrium structure, with the relaxation rate given by the emergent energy scale of impurity screening. Also, snaphots of the time-evolving spatial profile of impurity-bath correlators show exponential dependences on space, with the length scale given by the screening length.

We investigate the evolution of interfaces among phases of the interstellar medium with different temperature. It is found that, for some initial conditions, the dynamical effects related to conductive fronts are very important even if radiation losses, which tend to decelerate the front propagation, are taken into account. We have also explored the consequences of the inclusion of shear and bulk viscosity, and we have allowed for saturation of the kinetic effects. Numerical simulations of a cloud immersed in a hot medium have been performed; depending on the ratio of conductive to dynamical time, the density is increased by a huge factor and the cloud may become optically thick. Clouds that are highly compressed are able to stop the evaporation process even if their initial size is smaller than the Field length. In addition to the numerical approach, the time dependent evolution has been studied also analytically. Simple techniques have been applied to the problem in order to study the transition stages to a stationary state. The global properties of the solution for static and steady fronts and useful relations among the various physical variables are derived; a mechanical analogy is often used to clarify the physics of the results. It is demonstrated that a class of soliton-like solutions are admitted by the hydrodynamical equations appropriate to describe the conduction/cooling fronts (in the inviscid case) that do not require a heat flux at the boundaries. Some astrophysical consequences are indicated along with some possible applications to the structure of the Galactic ISM and to extragalactic objects.

The report investigates the effects of cumulus clouds on the temporal and spatial characteristics of atmospheric energy content. Changes in energy content of the cloud environment and the flux of energy are shown as functions of height and radial distance from the cloud axis. Energy related to water vapor accounts for most of the energy change in the cloud's vicinity. In the outer region, changes in water-vapor enthalpy are counterbalanced by changes in dry-air enthalpy, but potential energy change dominates. The total energy used in attempting to to decrease conditional atmospheric instability is given by the total amount of energy produced by the condensate formed, regardless of whether it falls as rain. The study presents data which, together with reasonable assumptions about the natural occurrence of cloud cells, leads to an estimated relaxation time of convection of about ten hours.

The different roles played by orbital dynamics and dissipative cloud-cloud collisions in the formation of giant molecular clouds (GMCs) in a global spiral structure are investigated. The interstellar medium (ISM) is simulated by a system of particles, representing clouds, which orbit in a spiral-perturbed, galactic gravitational field. The overall magnitude and width of the global cloud density distribution in spiral arms is very similar in the collisional and collisionless simulations. The results suggest that the assumed number density and size distribution of clouds and the details of individual cloud-cloud collisions have relatively little effect on these features. Dissipative cloud-cloud collisions play an important steadying role for the cloud system's global spiral structure. Dissipative cloud-cloud collisions also damp the relative velocity dispersion of clouds in massive associations and thereby aid in the effective assembling of GMC-like complexes.

The major physical processes responsible for shaping and sculpting pillars in the clouds surrounding massive stars (i.e. the `Pillars of Creation') are now being robustly incorporated into models quantifying the ionizing radiation from massive stars. The detailed gas dynamics within these pillars can now be compared with observations. Our goal is to quantify the gas dynamics in a pillar being sculpted by a nearby massive star. To do this, we use the CO, $^{13}$CO, and C$^{18}$O J=1-0 emission towards a pillar in the Vulpecula Rift. These data are a combination of CARMA and FCRAO observations providing high resolution ($\sim5''$) imaging of large scale pillar structures ($>100''$). We find that this cold ($\sim18$ K), low density material ($8\times10^3$ cm$^{-3}$) material is fragmenting on Jeans scales, has very low velocity dispersions ($\sim0.5$ km s$^{-1}$), and appears to be moving away from the ionizing source. We are able to draw direct comparisons with three models from the literature, and find that those with lower velocity dispersions best fit our data, although the dynamics of any one model do not completely agree with our observations. We do however, find that our observed pillar exhibits many of the characteristics expected from simulations.

Post equinox imaging of Uranus by HST, Keck, and Gemini telescopes has enabled new measurements of winds over previously sampled latitudes as well as measurements at high northern latitudes that have recently come into better view. These new observations also used techniques to greatly improve signal to noise ratios, making possible the detection and tracking of more subtle cloud features. The 250 m/s prograde jet peaking near 60 N was confirmed and more accurately characterized. Several long-lived cloud features have also been tracked. The winds pole-ward of 60 N are consistent with solid body rotation at a westward (prograde) rate of 4.3 deg/h with respect to Uranus' interior. When combined with 2007 and other recent measurements, it is clear that a small but well-resolved asymmetry exists in the zonal profile at middle latitudes, peaking at 35 deg, where southern winds are 20 m/s more westward than corresponding northern winds. High S/N Keck II imaging of the north polar region of Uranus reveals a transition from streaky bands below 60 N to a region from 60 deg to nearly the north pole, where widely distributed small bright spots, resembling cumulus cloud fields, with several isolated dark spots, are the dominant style of cloud features. This presents a stark contrast to 2003 detailed views of the south polar region of Uranus when no discrete cloud features could be detected in comparable Keck II near-IR images. The pressure levels of discrete clouds estimated from spatial modulations in H and Hcont images indicate that the polar cloud features are generally in the 1.3 to 2-3 bar range, as are equatorial and several mid-latitude features. Several of the brighter mid latitude features are found above the 1.2-bar level of methane condensation.

Goals of this research have been to identify physical processes that determine the dynamics of marine cloud layers and to quantify roles of turbulence, convection and thermal radiation that play in formation. dissipation and stability of the marine cloud layers. And immediate objectives of the research are to advance turbulence models, use efficient numerical schemes, develop computer simulation programs, simulate the marine cloud layers and compare computer results with published experimental data on the marine cloud layers so as to yield insights into the cloud's physical processes. For these objectives, two theoretical models. using the second order turbulence closure and the large-eddy simulation (LES), respectively, have been developed. In addition. a hybrid model has been presented. It uses a framework of multidimensional LES model but uses turbulence intensity values calculated by unidimensional second order closure turbulence equations. Results of the computer simulation are compared with experimental data retrieved from reliable web-site sources.

We survey the kinematics of over one hundred and fifty candidate (and potentially star-forming) dense cores in the Perseus molecular cloud with pointed N2H+(1-0) and simultaneous C18O(2-1) observations. Our detection rate of N2H+ is 62%, rising to 84% for JCMT SCUBA-selected targets. In agreement with previous observations, we find that the dense N2H+ targets tend to display nearly thermal linewidths, particularly those which appear to be starless (using Spitzer data), indicating turbulent support on the small scales of molecular clouds is minimal. For those N2H+ targets which have an associated SCUBA dense core, we find their internal motions are more than sufficient to provide support against the gravitational force on the cores. Comparison of the N2H+ integrated intensity and SCUBA flux reveals fractional N2H+ abundances between 10^-10 and 10^-9. We demonstrate that the relative motion of the dense N2H+ gas and the surrounding C18O gas is less than the sound speed in the vast majority of cases (~90%). The point-to-point motions we observe within larger extinction regions appear to be insufficient to provide support against gravity, although we sparsely sample these regions.

Near-infrared adaptive optics imaging of Uranus by the Keck 2 telescope during 2003 and 2004 has revealed numerous discrete cloud features, 70 of which were used to extend the zonal wind profile of Uranus up to 60\deg N. We confirmed the presence of a north-south asymmetry in the circulation (Karkoschka, Science 111, 570-572, 1998), and improved its characterization. We found no clear indication of long term change in wind speed between 1986 and 2004, although results of Hammel et al. (2001, Icarus 153, 229-235) based on 2001 HST and Keck observations average ~10 m/s less westward than earlier and later results, and 2003 observations by Hammel et al. (2005, Icarus 175, 534-545) show increased wind speeds near 45\deg N, which we don't see in our 2003-2004 observations. We observed a wide range of lifetimes for discrete cloud features: some features evolve within ~1 hour, many have persisted at least one month, and one feature near 34\deg S (termed S34) seems to have persisted for nearly two decades, a conclusion derived with the help of Voyager 2 and HST observations. S34 oscillates in latitude between 32\deg S and 36.5\deg S, with a period of $\sim$1000 days, which may be a result of a non-barotropic Rossby wave. It also varied its longitudinal drift rate between -20\deg /day and -31\deg /day in approximate accord with the latitudinal gradient in the zonal wind profile, exhibiting behavior similar to that of the DS2 feature observed on Neptune (Sromovsky et al., Icarus 105, 110-141, 1993). S34 also exhibits a superimposed rapid oscillation with an amplitude of 0.57\deg in latitude and period of 0.7 days, which is approximately consistent with an inertial oscillation.

#Microsoft #MicrosoftKorea #AI #CRM #Dynamics365 #MegazoneCloud 이번 영상에서는 AI를 활용하여 사용자 경험을 개선하고 영업 생산성을 향상시키는 Dynamics 365 Sales 데모를 소개합니다. 최신 기술을 통해 어떻게 비즈니스 효율성을 극대화할 수 있는지 알아보세요. ✨한국마이크로소프트의 다양한 소식을 알고 싶다면? ✨ 링크드인 🔗http://msft.it/6051YH7o1 페이스북 브랜드 채널 🔗http://msft.it/6052YH7oG X 브랜드 채널 🔗http://msft.it/6053YH7oH 페이스북 비즈니스 라운지 채널 🔗http://msft.it/6054YH7oy 페이스북 개발자 채널 🔗http://msft.it/6055YH7oJ X 개발자 채널 🔗http://msft.it/6056YH7oK

In this fluid dynamics video, the vapour cloud generated near evaporating free liquid surfaces is visualised by Mach-Zehnder interferometry (MZI). More precisely, for evaporating HFE-7100 (from 3M) and ambient conditions, the vapour concentration field and its dynamical behaviour are observed in three simple experiments. Through these experiments, it is evidenced that the high density of the vapour cloud (compared to air) induces convective motions in the gas mixture, resulting in deviations of the concentration field from a purely diffusional behaviour.

Solution Architects Luca Pellegrini and Volker Deuss join us to talk about Dynamics 365. A great talk with their experience and opinions on onboarding, cloud implementation, the direction of the Dynamics 365 product and more. Watch this on Youtube:  https://youtu.be/HULRrEleJ5I REFERENCES The Microsoft Business Forward event: https://www.microsoft.com/en-us/dynamics365/business-forward Satya Nadella in the trenches: https://www.youtube.com/watch?v=8bSCIUAeLis&feature=youtu.be&t=1h44m50s Sandvik IoT demo at //Build/: https://channel9.msdn.com/events/Build/2017/KEY01#time=19m00s Special shout out to Waldemar Pross: http://waldemarpross.com  (Sorry about blanking on your name) Hosts: Fredrik Sætre — @AxFredrik http://www.dynaxtips.com Tommy Skaue — @Skaue http://yetanotherax.com Guests: Luca Pellegrini — @LucoPelle Technical Architect @ QuantiQ Technology Volker Deuss — @VolkerDeuss Technical Solution Architect & Developer @ GWS /////////////////////////////////////////////////////////////// Be a part of the community! http://www.dynamicsuser.net/ http://community.dynamics.com/ http://www.iamcp.org/ http://dynamiccommunities.com ////////////////////////////////////////////////////////////// Don’t forget to Like and subscribe! Music courtesy of Cannavo&Nesse

We holographically study the effect of back reaction on the hydrodynamical properties of $\mathcal{N} = 4$ strongly coupled super Yang-Mills (SYM) thermal plasma. The back reaction we consider arises from the presence of static heavy quarks uniformly distributed over $\mathcal{N} = 4$ SYM plasma. In order to study the hydrodynamical properties, we use heavy quark as well as heavy quark-antiquark bound state as probes and compute the jet quenching parameter, screening length and binding energy. We also consider the rotational dynamics of heavy probe quark in the back-reacted plasma and analyse associated energy loss. We observe that the presence of back reaction enhances the energy-loss in the thermal plasma. Finally, we show that there is no effect of angular drag on the rotational motion of quark-antiquark bound state probing the back reacted thermal plasma.

A coupled map model for cloud dynamics is proposed, which consists of the successive operations of the physical processes; buoyancy, diffusion, viscosity, adiabatic expansion, fall of a droplet by gravity, descent flow dragged by the falling droplet, and advection. Through extensive simulations, the phases corresponding to stratus, cumulus, stratocumulus and cumulonimbus are found, with the change of the ground temperature and the moisture of the air. They are characterized by order parameters such as the cluster number, perimeter-to-area ratio of a cloud, and Kolmogorov-Sinai entropy.

We have combined a two-dimensional chemical/dynamics model with a monodisperse parameterization of polar mesospheric clouds (PMCs) to study the interaction of PMCs with the climate of the summer mesopause region. First, we show that PMC absorption of terrestrial and solar IR radiation lead to atmospheric heating rates which can exceed 10 degrees Kelvin/day. This heat is dissipated by increased upwelling above the cloud layer and by a 2-6 degree Kelvin temperature increase. We then calculate the global PMC ice mass and evaluate its sensitivity to IR heating, assumed particle size and level of solar activity. Inclusion of the temperature increase in the model can reduce the calculated ice mass by up to a factor of two. The calculated solar cycle range in the ice mass is also about a factor of two. The calculated latitude distribution and solar cycle range of PMC ice mass are in good agreement with recent analyses of PMC satellite data. Finally, we test the hypothesis that PMC formation leads to ozone changes by comparing our model with ozone data from the Halogen Occultation Experiment (HALOE). The data show a 20-30% ozone enhancement above PMCs. In the model, dehydration above the cloud layer leads to an ozone increase due to lowered HOx. However, this competes with the temperature increase from IR absorption that can damp out this ozone increase. Surprisingly, for realistic estimates of the terrestrial IR flux, the model ozone response is reduced to well below that observed by HALOE.

The interaction between vegetation and the atmosphere is highly complex in fog affected ecosystems like Tropical Montane Cloud Forests (TMCFs). Despite acknowledging fog effects on the canopy's water balance, quantifying their influence remains challenging. While the reduction in potential evaporation that is caused by fog presence, is largely independent of land cover, fog interception itself strongly depends on the land-cover's vegetation characteristics. A better understanding of how these two fog related processes affect the water balance is highly relevant under current land-use and climate-change pressures. In this study we evaluate the different fog effects on TMCFs’ canopy interception combining model simulations and high temporal resolution (10 min) observations that were collected in different TMCF regeneration stages: early succession, secondary and old-growth TMCFs. We also analyse the difficulties in closing catchment water balances caused by limitations on the interpretation of throughfall data to properly represent these fog effects. Results show that different fog frequencies along elevation affect potential evaporation. The higher elevation old-growth TMCFs have a lower simulated evaporation and a lower dry canopy frequency than the low elevation secondary and early succession forests. Furthermore, we show that fog water inputs during fog-only events, even though higher at the higher elevation, are irrelevant as water inputs (from 0.8% to 1.6% of measured rainfall), but fog's contribution to through-fall during foggy rainfall events can be more relevant (from 5.8%–12.8% of measured rainfall). Additional to the fog trends along the elevation, we also uncover variable fog-vegetation interactions controlled by differences in canopy water storages as a function of forest cover. Each evaluated process has associated uncertainties, which together cumulatively explain why closing a water budget in TMCF catchments is limited by data collection methods that probably do not capture all relevant fog effects. In addition, this study also indicates that the temporal resolution of measured rainfall and through-fall and compensating effects of canopy parameters that are estimated by the commonly used Rutter canopy-rainfall interception model, pose an additional challenge to understand and quantify fog effects in the water budgets of TMCFs.

Goals of this research have been to identify physical processes that determine the dynamics of the marine cloud layers and to quantify roles of turbulence, convection and thermal radiation that play in formation, dissipation and stability of the marine cloud layers. And immediate objectives of the research are to advance turbulence models, use efficient numerical schemes, develop computer simulation programs, simulate the marine cloud layers and compare computer results with published experimental data on the marine cloud layers so as to yield insights into the cloud's physical processes.

The large dynamic range of star formation in galaxies, and the apparently complex environmental influences involved in triggering or suppressing star formation, challenges the understanding. The key to this understanding may be the detailed study of simple physical models for the dominant nonlinear interactions in interstellar cloud systems. One such model is described, a generalized Oort model cloud fluid, and two simple applications of it are explored. The first of these is the relaxation of an isolated volume of cloud fluid following a disturbance. Though very idealized, this closed box study suggests a physical mechanism for starbursts, which is based on the approximate commensurability of massive cloud lifetimes and cloud collisional growth times. The second application is to the modeling of colliding ring galaxies. In this case, the driving processes operating on a dynamical timescale interact with the local cloud processes operating on the above timescale. The results is a variety of interesting nonequilibrium behaviors, including spatial variations of star formation that do not depend monotonically on gas density.

The lowest-mass stars, brown dwarfs and extrasolar planets present challenges and opportunities for understanding dynamics and cloud formation processes in low-temperature atmospheres. For brown dwarfs, the formation, variation and rapid depletion of photospheric clouds in L- and T-type dwarfs, and spectroscopic evidence for non-equilibrium chemistry associated with vertical mixing, all point to a fundamental role for dynamics in vertical abundance distributions and cloud/grain formation cycles. For exoplanets, azimuthal heat variations and the detection of stratospheric and exospheric layers indicate multi-layered, asymmetric atmospheres that may also be time-variable (particularly for systems with highly elliptical orbits). Dust and clouds may also play an important role in the thermal energy balance of exoplanets through albedo effects. For all of these cases, 3D atmosphere models are becoming an increasingly essential tool for understanding spectral and temporal properties. In this review, I summarize the observational evidence for clouds and dynamics in cool dwarf and hot exoplanetary atmospheres, outstanding problems associated with these processes, and areas where effective synergy can be achieved.