Thermodynamic Environment Research Articles

Tornadic waterspout event in Split (Croatia) - analysis of meteorological environment

The aim of this paper is the waterspout in Split (φ 43.51 °N, λ 16.45 E, h = 0 m) observed on January 6, 2016, which swept over the city at 15:40–16:00 CET (14:40-15:00 UTC). There were convective developments in upper-level south-west flow within the cloudiness which followed the low-level cyclone and associated frontal disturbances. There was an intense thermodynamic instability in lower and mid layers of the atmosphere-the passage of the cold front as a main synoptic feature over the warm Adriatic water, pronounced directional and speed wind shear, as well as the presence of jet stream and a pronounced horizontal field of positive divergence above the observed area. The aim of this paper is to investigate synoptic and mesoscale situation, and meteorological conditions which created favourable thermodynamic environment which preceded the waterspout development.

Meio ambiente e o ensino de dilatação térmica na perspectiva de um grupo de professores de Física do ensino médio

A abordagem teórica da termodinâmica juntamente com sua contextualização proporciona uma melhor compreensão dos fenômenos do dia a dia. Da mesma forma, as conexões da termodinâmica com os processos do meio ambiente proporcionam para os estudantes uma melhor compreensão dos conceitos e uma abordagem interdisciplinar. Dentre os diversos tópicos ensinados em Física no Ensino Médio, a dilatação térmica é um conteúdo no qual os estudantes e professores sem licenciatura em Física apresentam dificuldades. Desta forma, o presente trabalho faz parte de um estudo sobre o ensino de dilatação térmica, tendo como principal objetivo conhecer a perspectiva de um grupo de professores de física sobre o assunto, possibilitando a compreensão de quais conceitos relacionados a esse tema que mais apresentam problemas de ensino e aprendizagem. Para tanto, foi aplicado um questionário a um grupo formado por cinco professores de física, com o objetivo de conhecer a perspectiva desses professores sobre o ensino, levando em consideração que o ensino de física deve tornar os estudantes capazes de entender, participar e intervir nas situações que o cercam.

Measured oscillator strengths in singly ionized molybdenum

In this article, 112 oscillator strengths from Mo II have been measured, 79 of which for the first time. The radiative parameters have been obtained by laser-induced breakdown spectroscopy (LIBS). The plasma is produced from a fused glass sample prepared from molybdenum oxide with a Mo atomic concentration of 0.1%. The plasma evolved in air at atmospheric pressure, and measurements were carried out with the following plasma parameters: an electron density of cm−3 and an electron temperature of K. In these conditions, a local thermodynamic equilibrium environment and an optically thin plasma were confirmed for the measurements. The relative intensities were placed on an absolute scale by combining branching fractions with the measured lifetimes and by comparing well-known lines using the plasma temperature. Comparisons were made to previously obtained experimental and theoretical values wherever possible.

Clarifying the definition of a sedimentary rock and the thermodynamic environment in the lower stratisphere

It is shown that the definition of a sedimentary rock that has been given by the classical lithologists L.V. Pustovalov, M.S. Shvetsov, L.B. Rukhin, and U.H. Twonhozhel, among others, does not conform to the modern understanding of the sedimentary process, which covers not only the surface of the planet, but also the Earth’s deep interior with high thermodynamic indices (a pressure of up to 8100 kgf/cm and a temperature of up to 800–900°C).

Observations of a Nondeveloping Tropical Disturbance in the Western North Pacific during TCS-08 (2008)

Abstract Large uncertainty still remains in determining whether a tropical cloud cluster will develop into a tropical cyclone. During The Observing System Research and Predictability Experiment (THORPEX) Pacific Asian Regional Campaign (T-PARC)/Tropical Cyclone Structure-2008 (TCS-08) field experiment, over 50 tropical cloud clusters were monitored for development, but only 4 developed into a tropical cyclone. One nondeveloping tropical disturbance (TCS025) was closely observed for potential formation during five aircraft research missions, which provided an unprecedented set of observations pertaining to the large-scale and convective environments of a nondeveloping system. The TCS025 disturbance was comprised of episodic convection that occurred in relation to the diurnal cycle along the eastern extent of a broad low-level trough. The upper-level environment was dominated by two cyclonic cells in the tropical upper-tropospheric trough (TUTT) north of the low-level trough in which the TCS025 circulation was embedded. An in-depth examination of in situ observations revealed that the nondeveloping circulation was asymmetric and vertically misaligned, which led to larger system-relative flow on the mesoscale. Persistent environmental vertical wind shear and horizontal shearing deformation near the circulation kept the system from becoming better organized and appears to have allowed low equivalent potential temperature () air originating from one of the TUTT cells to the north (upshear) to impact the thermodynamic environment of TCS025. This in turn weakened subsequent convection that might otherwise have improved alignment and contributed to the transition of TCS025 to a tropical cyclone.

Simultaneous influences of thermodynamics and aerosols on deep convection and lightning in the tropics

AbstractConvective features (CFs) observed by the Tropical Rainfall Measuring Mission satellite between 2004 and 2011 are analyzed to determine the relative roles of thermodynamics and aerosols as they modulate radar reflectivity and lightning. We studied the simultaneous impacts of normalized convective available potential energy (NCAPE) and warm cloud depth (WCD) as well as cloud condensation nuclei concentrations (D ≥ 40 nm; N40) on total lightning density (TLD), average height of 30 dBZ echoes (AVGHT30), and vertical profiles of radar reflectivity (VPRR) within individual CFs. The results show that TLD increases by up to 600% and AVGHT30 increases by up to 2–3 km with increasing NCAPE and N40 for fixed WCD. The partial sensitivities of TLD/AVGHT30 to NCAPE and N40 separately were comparable in magnitude but account for a fraction of the total range of variability (i.e., when the influences of NCAPE and N40 are considered simultaneously). Both TLD and AVGHT30 vary inversely with WCD such that maxima of TLD and AVGHT30 are found for the combination of high NCAPE, high N40, and shallower WCD. The relationship between lightning and radar reflectivity was shown to vary as a function of N40 for a fixed thermodynamic environment. Analysis of VPRRs shows that reflectivity in the mixed phase region is up to 5.0–5.6 dB greater for CFs in polluted environments compared to CFs in pristine environments (holding thermodynamics fixed). This analysis favors a merged hypothesis for the simultaneous roles of thermodynamics and aerosols as they influence deep convective clouds in the Tropics.

Convective response to changes in the thermodynamic environment in idealized weak temperature gradient simulations

AbstractWe investigate the response of convection to idealized perturbations in the thermodynamic environment in simulations which parameterize the large‐scale circulations using the weak temperature gradient (WTG) approximation. The perturbations include a combination of modifying the environmental moisture and atmospheric stability via imposing anomalies in reference moisture and temperature profiles. We find that changes in atmospheric stability strongly influence the character of convection by drastically modifying the vertical motion profile, whereas changes to atmospheric moisture modulate the intensity of precipitation produced by the convection, but do not qualitatively change the shape of the vertical motion profile. An important question is how does horizontal moisture advection into the domain affect convection? We test several different parameterizations of this process; these include lateral entrainment by circulations induced by enforcing WTG, a moisture relaxation which parameterizes the advection of moisture by large‐scale nondivergent circulations, and control simulations in which both of these mechanisms are turned off so horizontal advection is assumed negligible compared to vertical advection. Interestingly, the most significant differences resulting from the choice of horizontal moisture advection scheme appear in environmental conditions which suppress–rather than support–the development of deep tropical convection. In this case, lateral entrainment related to WTG circulations is the only parameterization which results in extreme drying of the troposphere in environments which suppress convection. Consequently, this is the only parameterization which permits multiple equilibria—dry or precipitating steady states—in convection.

How thermodynamic environments control stratocumulus microphysics and interactions with aerosols

Aerosol–cloud interactions are central to climate system changes and depend on meteorological conditions. This study identifies distinct thermodynamic regimes and proposes a conceptual framework for interpreting aerosol effects. In the analysis, ten years (2003–2012) of daily satellite-derived aerosol and cloud products are combined with reanalysis data to identify factors controlling Southeast Atlantic stratocumulus microphysics. Considering the seasonal influence of aerosol input from biomass burning, thermodynamic environments that feature contrasting microphysical cloud properties and aerosol–cloud relations are classified. While aerosol impact is stronger in unstable environments, it is mostly confined to situations with low aerosol loading (aerosol index AI ≲ 0.15), implying a saturation of aerosol effects. Situations with high aerosol loading are associated with weaker, seasonally contrasting aerosol-droplet size relationships, likely caused by thermodynamically induced processes and aerosol swelling.

Changes in U.S. East Coast Cyclone Dynamics with Climate Change

Abstract Previous studies investigating the impacts of climate change on extratropical cyclones have primarily focused on changes in the frequency, intensity, and distribution of these events. Fewer studies have directly investigated changes in the storm-scale dynamics of individual cyclones. Precipitation associated with these events is projected to increase with warming owing to increased atmospheric water vapor content. This presents the potential for enhancement of cyclone intensity through increased lower-tropospheric diabatic potential vorticity generation. This hypothesis is tested using the Weather Research and Forecasting Model to simulate individual wintertime extratropical cyclone events along the United States East Coast in present-day and future thermodynamic environments. Thermodynamic changes derived from an ensemble of GCMs for the IPCC Fourth Assessment Report (AR4) A2 emissions scenario are applied to analyzed initial and lateral boundary conditions of observed strongly developing cyclone events, holding relative humidity constant. The perturbed boundary conditions are then used to drive future simulations of these strongly developing events. Present-to-future changes in the storm-scale dynamics are assessed using Earth-relative and storm-relative compositing. Precipitation increases at a rate slightly less than that dictated by the Clausius–Clapeyron relation with warming. Increases in cyclone intensity are seen in the form of minimum sea level pressure decreases and a strengthened 10-m wind field. Amplification of the low-level jet occurs because of the enhancement of latent heating. Storm-relative potential vorticity diagnostics indicate a strengthening of diabatic potential vorticity near the cyclone center, thus supporting the hypothesis that enhanced latent heat release is responsible for this regional increase in future cyclone intensity.

Experimental Studies on AeroThermodynamic Environments of the Interaction Area between the Wing and the Arc Board in Arc Wind Tunnel

The experimental studies on aero thermodynamic environments of the interaction area between the wing and its baseboard (the arc board) were conducted in the arc wind tunnel. In the experiments, the angle between the fluid from the nozzle and the board- wing was 15 degrees and the coming Mach numbers were5.1 and 5.8. Some cold wall heat fluxes on the board near the wing foot and the forepart of the wing tine were measured. The results showed, for the board near the wing foot, the cold wall heat fluxes first increased and then reduced after increasing to the biggest along the flow field as the attack angle increased; For the forepart of the wing tine, the cold wall heat flux was smaller whether the attack angle increased, which meant that the down dream wing had no influence on the cold wall heat flux. Meanwhile, the cold wall fluxes on the board near the wing foot increased along with the increase of the attack angle of the board-wing. That is to say that the interaction area was more close to the wing root. In addition, the heat flux suddenly decreased and then increased when the total enthalpy was less than 6000kJ/kg.

Simulations of Stratus Clouds over Eastern China in CAM5: Sensitivity to Horizontal Resolution

Abstract This paper evaluates the simulations of stratus clouds over eastern China (EC) in the Community Atmosphere Model, version 5 (CAM5), with an emphasis on the impact of changing horizontal resolutions on the performance. CAM5 in all experiments generally satisfactorily simulates the cloud radiative features over EC, including the spatial distributions of the continental shortwave cloud radiative forcing (SWCF) and stratus regimes, the responses of SWCF to the dynamic and thermodynamic ambient environment, and several relations in the environmental fields that are favorable to the stratus formation. Meanwhile, all experiments suffer from similar biases. Models tend to underestimate the stratus amount because of a corresponding underestimate of stratus occurrence frequency, while the stratus amount when present (AWP) is generally higher than that in the observation. Models also simulate similar errors in the environmental fields. The differences between low- and high-resolution experiments are distinct. An increase of resolution enhances the SWCF in southern China, but the skill deteriorates in the Sichuan basin. Correspondingly, the stratus amount increases in southern China from low- to high-resolution experiments, mainly because of more stratus occurrences, which are found to be related to the better represented environmental fields in the high-resolution experiments, especially the dynamic component. Several relations in the ambient environment are also slightly improved in the high-resolution experiments. Meanwhile, the reason for the decrease of stratus AWP within the Sichuan basin, which is mainly responsible for the decreased stratus amounts and weaker SWCF from low- to high-resolution experiments, is also discussed.

Analysis of a Destructive Wind Storm on 16 November 2008 in Brisbane, Australia

AbstractDuring the late afternoon on 16 November 2008 the Brisbane (Queensland, Australia) suburb of “The Gap” experienced extensive wind damage caused by an intense local thunderstorm. The CP2 research radar nearby detected near-surface radial velocities exceeding 43 m s−1 above The Gap while hail size reports did not exceed golf ball size, and no tornadoes were reported. The storm environment was characterized by a layer of very moist near-surface air and strong storm-relative low-level flow, whereas the storm-relative winds aloft were weak. While the thermodynamic storm environment contained a range of downdraft-promoting ingredients such as a ~4-km-high melting level above a ~2-km-deep layer with nearly dry-adiabatic lapse rates mostly collocated with dry ambient air, a ~1-km-deep stable layer near the ground would generally lower expectations of destructive surface winds based on the downburst mechanism. Once observed reflectivities exceed 70 dBZ, downdraft cooling due to hail melting and downdraft acceleration based on hail loading are found to likely become nonnegligible forcing mechanisms. The event featured the close proximity of a hydrostatically and dynamically driven mesohigh at the base of the downdraft to a dynamically driven mesolow associated with a low-level circulation. This proximity was instrumental in the anisotropic horizontal acceleration of the near-ground outflow and the ultimate strength of the Gap storm surface winds. Weak storm-relative midlevel winds are speculated to have allowed the downdraft to descend close to the low-level circulation, which set up this strong horizontal perturbation pressure gradient.

Combined Ab Initio and Interatomic Potentials Based Assessment of the Defect Structure of Mn-Doped SrTiO3

The energetics of doping SrTiO3 with Mn is investigated using density functional theory calculations within the GGA + U scheme and lattice statics simulations. Defect formation energies are derived for different Mn charge states and for occupation at both the Sr- and Ti-sites. For the GGA + U calculations, due consideration is given to finite-size effects and the treatment of the chemical potential of atomic oxygen to avoid errors associated with direct DFT calculations of the oxygen dimer. The lattice statics calculations have been completed using a recently developed potential model designed for the investigation of rare-earth and transition metal doping of SrTiO3. Intrinsic defects have also been considered in all possible charge states. The GGA + U calculations predict that for the three different thermodynamic environments examined both Mn2+ and Mn4+ ions occupy the Ti-site via either oxygen vacancy compensation (Mn2+) or no charge compensation (Mn4+). This is contradictory to the lattice statics cal...

Investigating the Effect of the “Land between the Lakes” on Storm Patterns

AbstractThe artificially created region around the “Land between the Lakes” (LBL) in Kentucky represents unique land use and land cover (LULC) heterogeneities. Over a distance of 100 km, the LULC comprises artificially created open water bodies (i.e., two parallel large run-on-river dams separated by the LBL), mountainous terrain, forest cover, and extensive agricultural land. Such heterogeneities increase (decrease) moisture supply and sensible heat, resulting in a differential air mass boundary that helps to initiate (inhibit) convection. Hence, the LBL can potentially modify precipitation formation. Historical anecdotes reveal a tendency for storms to dissipate or reintensify near the LBL. The specific scientific question pursued in this study is therefore the following: Has the unique development of two parallel run-on-river reservoirs and the surrounding LULC heterogeneity modified storm patterns in the region? Ten storm events during the growing season were selected. Two additional events, observed by the newly established high-resolution Kentucky Mesonet network, were also considered. Radar reflectivity images were visually inspected to understand the evolution of convective cells that originated or were modified near the LBL. The Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) Model was used to determine near-surface trajectories that led to the selected events. The spatial synoptic classification and merged Geostationary Operational Environmental Satellite (GOES) IR images were analyzed to determine the prevailing synoptic conditions on the event dates. Six storm events showed a pattern wherein the convective cells lost strength as it passed over the LBL in a northeasterly direction. In two events, Next Generation Weather Radar (NEXRAD) reflectivity imagery revealed enhancement of convection as the storm passed over the LBL toward the Mississippi valley. Further dissection of the storm morphology suggested that the thermodynamic environment may have played an important role for the eight events where modification of precipitation near LBL has been clearly observed.

A combination of porous and crystalline characters in carbon aerogels by a synergistic graphitization

The synergistic graphitization of carbon aerogels (CAs) was carried out by annealing CAs containing different amounts of manganese additives in molten sodium metals at 800°C. Resulted samples were examined by X-ray diffraction, Raman scattering spectra, electron microscopy and gas physisorption methods. Effects of manganese additives and sodium metals on the synergistic graphitization were investigated. Graphitized CAs samples exhibit larger specific surface areas and total pore volumes than initial CAs and the graphitization of CAs can be adjusted at the same temperature by changing the content of manganese additives in CAs. The synergistic graphitization is related to the thermodynamic environment in CAs improved by the reduction of manganese additives in sodium metals. It results in a combination of porous and crystalline characters in graphitic carbons.

Size, Shape, Stability, and Color of Plasmonic Silver Nanoparticles

The remarkable relationship between the size, shape, and optical properties of silver nanoparticles is proving to be very useful in a range of high performance applications. Considerable effort and investment are focused on delivering silver nanoparticles with precise morphologies. However, the reliability of these particles is contingent upon the morphological stability, particularly against variations in the thermodynamic environment, such as changes in temperature. Using a combination of computational and theoretical approaches, we have constructed a size- and shape-dependent phase diagram of nanoscale silver and projected the optical emission spectrum to produce a detailed structure/property map at thermal equilibrium. This map demonstrates that faceted near-spherical shapes and spheres are the predominant morphologies in a Ag NPs colloidal sample at low and high temperatures, showing a light yellow color. However, samples with more faceted shapes such as cubes or tetrahedrons, which gain stability at...

Interaction between dynamics and thermodynamics during tropical cyclogenesis

Abstract. Observational data of tropical disturbances are analyzed in order to investigate tropical cyclogenesis. Data from 37 cases observed during three field campaigns are used to investigate possible correlations between various dynamic and thermodynamic variables. The results show that a strong mid-level vortex is necessary to promote spin up of the low-level vortex in a tropical cyclone. This paper presents a theory on the mechanism of this process. The mid-level vortex creates a thermodynamic environment conducive to convection with a more bottom-heavy mass flux profile that exhibits a strong positive vertical gradient in a shallow layer near the surface. Mass continuity then implies that the strongest horizontal mass and vorticity convergence occurs near the surface. This results in low-level vortex intensification. For two of the disturbances that were observed during several consecutive days, evolution of the dynamics and thermodynamics is documented. One of these disturbances, Karl, was observed in the period before it intensified into a tropical storm; the other one, Gaston, was observed after it unexpectedly decayed from a tropical storm to a tropical disturbance. A hypothesis on its decay is presented.

Anomalies, trends and variability in atmospheric fields related to hailstorms in north‐eastern Spain

ABSTRACTHailstorms have become a serious meteorological risk in mid‐latitude countries because of their small‐scale development and short time span, and their forecasting remains problematic. Moreover, the lack of reliable hailstorm databases is an important handicap for Numerical Weather Prediction (NWP) model validation, time trend studies and establishment of hailstorm relationships with global warming and climate change. However, this can be overcome by ascertaining physical relationships between favourable synoptic patterns and mesoscale trigger factors for hailstorm development in a local study area.North‐eastern Spain is one of the European regions with largest number of hailstorm days (HD) observed in the summer. Since 2001, from May through September, reliable databases of hailstorm occurrence in the middle Ebro Valley have been constructed, which include intensity, temporal frequency and spatial coordinate data. June and July 2006 had the largest number of HD in 2001–2010. With the objective of analysing meteorological factors responsible for this anomaly, atmospheric patterns at low and mid‐tropospheric levels were studied. We determined a set of special synoptic configurations, with an evident deviation from climatic values generating anomalies of 850 hPa temperature relative to the characteristic values of 2001–2010 and 1950–2010. An analysis of these anomalies detected a positive trend of 850 hPa temperature and geopotential height in the western Mediterranean area. As a consequence, the characteristic synoptic circulation has changed since 1950, towards low‐level patterns favouring adequate thermodynamic environments for hailstorm development in north‐eastern Spain. Finally, after a cluster analysis, we studied periodicities in the monthly 850 hPa temperature field to improve knowledge for seasonal forecasting of hailstorms.

Thermodynamic investigation and environment impact assessment of hydrogen production from steam reforming of poultry tallow

In this research, various assessment tools are applied to comprehensively investigate hydrogen production from steam reforming of poultry tallow (PT). These tools investigate the chemical reactions, design and simulate the entire hydrogen production process, study the energetic performance and perform an environment impact assessment using life cycle assessment (LCA) methodology.The chemical reaction investigation identifies thermodynamically optimal operating conditions at which PT may be converted to hydrogen via the steam reforming process. The synthesis gas composition was determined by simulations to minimize the Gibbs free energy using the Aspen Plus™ 10.2 software. These optimal conditions are, subsequently, used in the design and simulation of the entire PT-to-hydrogen process. LCA is applied to evaluate the environmental impacts of PT-to-hydrogen system. The system boundaries include rendering and reforming along with the required transportation process. The reforming inventories data are derived from process simulation in Aspen Plus™, whereas the rendering data are adapted from a literature review. The life cycle inventories data of PT-to-hydrogen are computationally implemented into SimaPro 7.3. A set of seven relevant environmental impact categories are evaluated: global warming, abiotic depletion, acidification, eutrophication, ozone layer depletion, photochemical oxidant formation, and cumulative non-renewable fossil and nuclear energy demand. The results are subject to a systematic sensitivity analysis and compared to those calculated for hydrogen production from conventional steam methane reforming.The LCA results indicate that the thermal energy production process is the main contributor to the selected environmental impact categories. Improvement actions to minimize the reforming thermal energy and the transport distance are strongly recommended as they would lead to relevant environmental improvements.

Note on invariant properties of a quantum system placed into thermodynamic environment

The analysis conducted in this work indicates that interactions of a CP-violating (and CPT-preserving) quantum system with a thermodynamic environment can produce the impression of a CPT violation in the system. This conclusion is reasonably consistent with the results reported for decays of neutral K-mesons.