bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inertia–Gravity Waves Spontaneously Generated by Jets and Fronts. Part I: Different Baroclinic Life Cycles
Authors: Plougonven Riwal , Snyder Chris 
Published: August 2007

Abstract
The spontaneous generation of inertia–gravity waves in idealized life cycles of baroclinic instability is investigated using the Weather Research and Forecasting Model. Two substantially different life cycles of baroclinic instability are obtained by varying the initial zonal jet. The wave generation depends strongly on the details of the baroclinic wave’s development. In the life cycle dominated by cyclonic behavior, the most conspicuous gravity waves are excited by the upper-level jet and are broadly consistent with previous simulations of O’Sullivan and Dunkerton. In the life cycle that is dominated by anticyclonic behavior, the most conspicuous gravity waves even in the stratosphere are excited by the surface fronts, although the fronts are no stronger than in the cyclonic life cycle. The anticyclonic life cycle also reveals waves in the lower stratosphere above the upper-level trough of the baroclinic wave; these waves have not been previously identified in idealized simulations. The sensitivities of the different waves to both resolution and dissipation are discussed.
Intraseasonal Variability in a Dry Atmospheric Model
Authors: Lin Hai , Brunet Gilbert , Derome Jacques 
Published: August 2007

Abstract
A long integration of a primitive equation dry atmospheric model with time-independent forcing under boreal winter conditions is analyzed. A variety of techniques such as time filtering, space–time spectral analysis, and lag regressions are used to identify tropical waves. It is evident that oscillations with intraseasonal time scales and a Kelvin wave structure exist in the model tropical atmosphere. Coherent eastward propagations in the 250-hPa velocity potential and zonal wind are found, with a speed of about 15 m s−1. The oscillation is stronger in the Eastern Hemisphere than in the Western Hemisphere.
Interactions between the tropical and extratropical flows are found to be responsible for the simulated intraseasonal variability. Wave activity flux analysis reveals that a tropical influence occurs in the North Pacific region where a northeastward wave activity flux is found associated with the tropical divergent flow in the western and central Pacific. In the North Atlantic sector, on the other hand, a strong extratropical influence is observed with a southward wave activity flux into the Tropics. The extratropical low-frequency variability develops by extracting kinetic energy from the basic mean flow and through interactions with synoptic-scale transient eddies. Linear experiments show that the tropical atmospheric response to the extratropical forcing in the North Atlantic leads to an eastward-propagating wave in the tropical easterly mean flow of the Eastern Hemisphere.
The Spectral Ice Habit Prediction System (SHIPS). Part I: Model Description and Simulation of the Vapor Deposition Process
Authors: Hashino T. , Tripoli G. J. 
Published: August 2007

Abstract
This paper describes the Spectral Ice Habit Prediction System (SHIPS), which represents a continuous-property approach to microphysics simulation in an Eulerian cloud-resolving model (CRM). A two-moment hybrid-bin method is adopted to predict the solid hydrometeor distribution, where the distribution is divided into the mass bins with a simple mass distribution inside each bin. Each bin is characterized by a single representative ice crystal habit and the type of solid hydrometeor. These characteristics are diagnosed based on a series of particle property variables (PPVs) of solid hydrometeors that reflect the history of microphysical processes and the mixing between bins and air parcels in space. Thus, SHIPS allows solid hydrometeors to evolve characteristics and size distribution based on their movement through a cloud.
SHIPS was installed into the University of Wisconsin-Nonhydrostatic Modeling System (UW-NMS) and tested for ice nucleation and vapor deposition processes. Two-dimensional idealized simulations were employed to simulate a winter orographic storm observed during the second Improvement of Microphysical Parameterization through Observational Verification Experiment (IMPROVE-2) campaign. The simulated vertical distributions of ice crystal habits showed that the dynamic advection of dendrites produces wider dendritic growth region than local atmospheric conditions suggest. SHIPS showed the sensitivities of the habit distribution in the low- and midlevel to the upper-level growth mode (T &lt; −20°C) of ice crystals through the sedimentation. Comparison of the results to aircraft observations casts doubt on the role of the columnar growth mode (T &lt; −20°C) traditionally thought to be dominant in the literature. The results demonstrated how the complexity of the vapor deposition growth of ice crystals, including dendrites and capped columns, in varying temperature and moisture lead to particular observed habits.
Near-Surface Intensification of Tornado Vortices
Authors: Lewellen D. C. , Lewellen W. S. 
Published: August 2007

Abstract
An idealized analytical model and numerical large-eddy simulations are used to explore fluid-dynamic mechanisms by which tornadoes may be intensified near the surface relative to conditions aloft. The analytical model generalizes a simple model of Barcilon and Fiedler and Rotunno for a steady supercritical end-wall vortex to more general vortex corner flows, angular momentum distributions, and time dependence. The model illustrates the role played by the corner flow swirl ratio in determining corner flow structure and intensification; predicts an intensification of near-surface swirl velocities relative to conditions aloft of Iυ ∼ 2 for supercritical end-wall vortices in agreement with earlier analytical, numerical, and laboratory results; and suggests how larger intensification factors might be achieved in some more general corner flows. Examples of the latter are presented using large-eddy simulations. By tuning the lateral inflow boundary conditions near the surface, quasi-steady vortices exhibiting nested inner and outer corner flows and Iυ ∼ 4 are produced. More significantly, these features can be produced without fine tuning, along with an additional doubling (or more) of the intensification, in a broad class of unsteady evolutions producing a dynamic corner flow collapse. These scenarios, triggered purely by changes in the far-field near-surface flow, provide an attractive mechanism for naturally achieving an intense near-surface vortex from a much larger-scale less-intense swirling flow. It is argued that, applied on different scales, this may sometimes play a role in tornadogenesis and/or tornado variability. This phenomenon of corner flow collapse is considered further in a companion paper.
Near-Surface Vortex Intensification through Corner Flow Collapse
Authors: Lewellen D. C. , Lewellen W. S. 
Published: August 2007

Abstract
Results are presented from a large set of large-eddy simulations of a class of unsteady vortex evolution that may sometimes play a role in tornadogenesis or tornado variability. Beginning with a high-swirl parent vortex with an excess of low-swirl flow through the surface/corner/core region, perturbation of the low-swirl near-surface inflow at a large radius can trigger a subsequent dynamic “corner flow collapse” producing dramatic near-surface intensification relative to conditions aloft of an order of magnitude or more in velocity scale. This paper presents a more detailed treatment of the physics and simulation of corner flow collapse, expanding upon the presentation given in a companion paper treating near-surface vortex intensification more generally for both steady and unsteady conditions. The basic scaling of the onset, intensification, structure, and duration of the phenomenon is explored as a function of some of the dominant physical parameters involved. A dimensionless rate of change of the low-swirl flux through the surface/corner flow during the process is identified as a critical governing parameter. Given the mode of triggering near the surface at large radii, the large intensification that can result, and the sensitivity to some of the parameters involved, corner flow collapse may provide a mechanism by which the rear-flank downdraft can promote tornadogenesis and help explain why seemingly similar conditions sometimes produce intense tornadoes and other times do not.
Maximum Entropy Production in Climate Theory
Authors: Goody Richard 
Published: August 2007

AbstractR. D. Lorenz et al. claim that recent data on Mars and Titan show that planetary atmospheres are in unconstrained states of maximum entropy production (MEP). Their model as it applies to Venus, Earth, Mars, and Titan is reexamined, and it is shown that their claim is not justified. This does not necessarily imply that MEP is incorrect, and inapplicable to atmospheres, but it does mean that the difficult and unexplored problem of dynamical constraints on the MEP solution must be understood if it is to be of value for climate research.
A New Surface Model for β-Plane Turbulence
Authors: Panayotova Iordanka N. 
Published: August 2007

Abstract
This paper introduces a new numerical model for studying wave–turbulence interactions in a continuously stratified rotating flow, having a uniform potential vorticity and a rigid boundary. The meridional variation in the Coriolis parameter (β effect), a channel geometry, and the first-order nonlinear terms in a small Rossby number expansion are included into the surface quasigeostrophic dynamics. The model contains important dynamical characteristics of three-dimensional flows such as advection by ageostrophic winds, and stretching and tilting of relative vorticity. Nevertheless, it has the computational economy of two-dimensional flows. Long-term direct numerical simulations are performed for decaying turbulence arising from random initial conditions.
In addition to the formation of steady zonal jets, frequently reported as a possible end state under the β effect, this model exhibits several other realistic physical effects that were lacking in the previously studied β-plane models for wave–turbulence interactions. There is a significant contrast in the spatial and time scales of the formed eddies, resulting in high meridional asymmetry of the flow. Mean surface cooling and persistent large-scale blocking eddies are observed as well. The surface potential temperature variance spectrum exhibits a well-resolved k−5/3 inertial range.
Entrainment-Mixing and Radiative Transfer Simulation in Boundary Layer Clouds
Authors: Chosson Frédérick , Brenguier Jean-Louis , Schüller Lothar 
Published: August 2007

Abstract
In general circulation models, clouds are parameterized and radiative transfer calculations are performed using the plane-parallel approximation over the cloudy fraction of each model grid. The albedo bias resulting from the plane-parallel representation of spatially heterogeneous clouds has been extensively studied, but the impact of entrainment-mixing processes on cloud microphysics has been neglected up to now. In this paper, this issue is examined by using large-eddy simulations of stratocumulus clouds and tridimensional calculations of radiative transfer in the visible and near-infrared ranges. Two extreme scenarios of mixing are tested: the homogeneous mixing scheme with constant concentration and reduced droplet sizes, against the inhomogeneous mixing scheme, with reduced concentration and constant droplet sizes. The tests reveal that entrainment-mixing effects at cloud top may substantially bias the simulated albedo. In the worse case, which corresponds to a fragmented and thin stratocumulus cloud, the albedo bias changes from −3% to −31% when using both mixing schemes alternatively.
Multiscale Models with Moisture and Systematic Strategies for Superparameterization
Authors: Majda Andrew J. 
Published: August 2007

AbstractThe accurate parameterization of moist convection presents a major challenge for the accurate prediction of weather and climate through numerical models. Superparameterization is a promising recent alternative strategy for including the effects of moist convection through explicit turbulent fluxes calculated from a cloud-resolving model. Basic scales for cloud-resolving modeling are the microscales on the order of 10 km in space on time scales on the order of 15 min, where vertical and horizontal motions are comparable and moist processes are strongly nonlinear (meso-gamma scale). In this paper, systematic multiscale asymptotic analysis is utilized to develop simplified microscale mesoscale dynamic (MMD) models for interaction between the microscales and spatiotemporal mesoscales on the order of 100 km and 2.5 h (meso-beta scale). The new MMD models lead to a systematic framework for superparameterization for numerical weather prediction (NWP) generalizing the traditional column modeling framework. The MMD formulation also provides a flexible systematic framework for devising new parameterization strategies for NWP intermediate between the two extremes of column modeling and detailed cloud-resolving modeling. It is also established here that these MMD models fit crudely into the recent systematic multiscale framework developed to explain the observed larger-scale statistical self-similarity of tropical convection, and therefore provide a systematic framework for superparameterization. Finally, it is shown that the new MMD models have the structure of a heterogeneous multiscale method so that many numerical techniques recently developed in the applied mathematics literature can be applied to this formulation.
Breaking Waves at the Tropopause in the Wintertime Northern Hemisphere: Climatological Analyses of the Orientation and the Theoretical LC1/2 Classification
Authors: Martius O. , Schwierz C. , Davies H. C. 
Published: August 2007

Abstract
Breaking waves on the tropopause are viewed as potential vorticity (PV) streamers on middle-world isentropic levels. A Northern Hemisphere winter climatology of the streamers’ spatial distribution and meridional orientation is derived from the 40-yr ECMWF Re-Analysis (ERA-40) dataset, and used to assess the nature and frequency of occurrence of breaking synoptic-scale waves. The streamers are grouped into two classes related to the so-called cyclonic (LC2) and anticyclonic (LC1) patterns, and the ambient wind strength and wind shear is also noted.
It is shown that the occurrence of cyclonic and anticyclonic PV streamers exhibits a distinct spatial variability in the horizontal and the vertical. The majority of cyclonic PV streamers are found on lower isentropic levels that intersect the tropopause at more poleward latitudes, whereas anticyclonic streamers predominate at higher elevations in the subtropics.
An analysis of the streamer patterns for the two phases of the North Atlantic Oscillation (NAO) reveals significant differences in the location and frequency of both cyclonic and anticyclonic streamers in the Euro–Atlantic region on the 310-K isentropic level. Likewise, for the two phases of the ENSO and the Pacific–North American (PNA) pattern, there are marked differences in the frequency pattern of cyclonic streamers. An examination of the tropopause-level hemispheric flow pattern at the time of and prior to a streamer’s formation indicates a linkage to the presence or absence of double jet structures.
Wave Energy Associated with the Variability of the Stratospheric Polar Vortex
Authors: Liberato M. L. R. , Castanheira J. M. , de la Torre L. , DaCamara C. C. , Gimeno L. 
Published: August 2007

Abstract
A study is performed on the energetics of planetary wave forcing associated with the variability of the northern winter polar vortex. The analysis relies on a three-dimensional normal mode expansion of the atmospheric general circulation that allows partitioning the total (i.e., kinetic + available potential) atmospheric energy into the energy associated with Rossby and inertio-gravity modes with barotropic and baroclinic vertical structures. The analysis mainly departs from traditional ones in respect to the wave forcing, which is here assessed in terms of total energy amounts associated with the waves instead of heat and momentum fluxes. Such an approach provides a sounder framework than traditional ones based on Eliassen–Palm (EP) flux diagnostics of wave propagation and related concepts of refractive indices and critical lines, which are strictly valid only in the cases of small-amplitude waves and in the context of the Wentzel–Kramers–Brillouin–Jeffries (WKBJ) approximation.
Positive (negative) anomalies of the energy associated with the first two baroclinic modes of the planetary Rossby wave with zonal wavenumber 1 are followed by a downward progression of negative (positive) anomalies of the vortex strength. A signature of the vortex vacillation is also well apparent in the lagged correlation curves between the wave energy and the vortex strength. The analysis of the correlations between individual Rossby modes and the vortex strength further confirmed the result from linear theory that the waves that force the vortex are those associated with the largest zonal and meridional scales.
The two composite analyses of displacement- and split-type stratospheric sudden warming (SSW) events have revealed different dynamics. Displacement-type SSWs are forced by positive anomalies of the energy associated with the first two baroclinic modes of planetary Rossby waves with zonal wavenumber 1; split-type SSWs are in turn forced by positive anomalies of the energy associated with the planetary Rossby wave with zonal wavenumber 2, and the barotropic mode appears as the most important component. In respect to stratospheric final warming (SFW) events, obtained results suggest that the wave dynamics is similar to the one in displacement-type SSW events.
An Interview with United States Senator Paul S. Sarbanes
Authors: Lucas Nance 
Published: August 2007

Senator Paul Spyros Sarbanes is the senior Democrat on the Senate Banking, Housing and Urban Affairs Committee. He was chairman of the committee when Sarbanes-Oxley was enacted. Senator Sarbanes is the longest-serving U.S. senator in Maryland history, having won his fifth term in 2000. He also serves on the Foreign Relations, the Budget and the Joint Economic Committees. He was born in Salisbury, Maryland, holds an undergraduate degree from Princeton and a law degree from Harvard. He was awarded a Rhodes Scholarship that brought him to Oxford, England. After law school, he clerked for Federal Judge Morris A. Soper before going into private practice with two Baltimore City law firms. In 1966, Sarbanes ran for the Maryland House of Delegates in Baltimore City and won. During his four years as a State Legislator in Annapolis he served on the Judiciary and the Ways and Means Committees. In 1970 he was elected to the United States House of Representatives, the first of three terms. While in the House, from 1971-76, Sarbanes served on the House Judiciary Committee, the Merchant Marine and Fisheries Committee, and the Select Committee on House Reorganization. It was during his service in the House, in August 1974, that Sarbanes was selected by his Democratic colleagues on the House Watergate Committee to introduce the first Article of Impeachment, for obstruction of justice, against President Richard Nixon. On November 2, 1976, Sarbanes was elected to the United States Senate. He was re-elected in 1982, 1988, 1994, and 2000. Throughout his public service, Senator Sarbanes has worked hard to provide the citizens of Maryland with dedicated, independent representation; representation based upon intelligence and integrity; representation which gives people the confidence that elected officials are there to serve the public interest. Paul Sarbanes was born in Salisbury, on Maryland's Eastern Shore on February 3, 1933. He is the son of Greek immigrants from Laconia, Greece -- Spyros (deceased 1957) and Matina Sarbanes (deceased 2001) who owned the Mayflower Restaurant on Salisbury's Main Street. The principles Senator Sarbanes learned growing up in Salisbury that have guided his public life are opportunity and fairness - principles that he strongly believes are fundamental to a decent and just society.
Moral Leadership in a Postmodern World
Authors: Thompson Lindsay J. 
Published: August 2007

This paper examines the gap between moral purpose and moral performance as a problem created in part by the alienation of spirituality from civic life. We are a nation ofprivatized morality that places corporate and civic leaders in a labyrinth of uncertainty when they try to establish a moral foundation for actions and decisions affecting the public interest. This uncertainty is compounded by an Enlightenment tradition of modern secular pluralism privileging rational discourse as the vehicle of public moral sentiment. In this longstanding intellectual tradition, reason is the highest good (Plato, Aristotle), the defining,feature of human subjectivity (Descartes), the foundation of human freedom (Kant, Hegel, Locke), and the path to moral truth (Kant). Although much of the intellectual, social, economic, and political energy of the last century has challenged the totalizing assumptions embedded in this tradition (Marx, Foucault, et alia), qualities of neutrality, objectivity, and universality remain as privileged values influencing cultural practices of morality and leadership. Leaders turn to reason, with its assumed qualities of tolerance and respect, in the attempt to cultivate organizational cultures of moral clarity, accountability, and trust without violating the intellectual and spiritual freedom of the individuals and groups who constitute the organizational culture. The problem with this approach is that moral solidarity - and, for that matter, genuine tolerance and respect -- are not a product of the intellect; they are a creation of the human spirit. In the secular tradition, spirituality is a private pursuit with no legitimate role in the public domain. This paper introduces a framework, the Moral Compass, as a possible approach for creating moral solidarity. The Moral Compass creates a conceptual framework and terminology the enables people to engage in meaningful, authentic moral dialogue and discernment while remaining anchored in the their unique moral traditions.