scholarly journals Development of a Misaligned Tropical Cyclone

2019 ◽  
Vol 77 (1) ◽  
pp. 79-111 ◽  
Author(s):  
David A. Schecter ◽  
Konstantinos Menelaou
Keyword(s):  
Tropical Cyclone ◽  
Tangential Velocity ◽  
Azimuthal Velocity ◽  
The Core ◽  
Cloud Resolving Model ◽  
Diabatic Processes ◽  
Extended Duration ◽  
The Difference ◽  
Maximum Tangential Velocity ◽  
Surface Vortex

Abstract A cloud-resolving model is used to examine the virtually shear-free evolution of incipient tropical cyclones initialized with different degrees of misalignment between the lower- and middle-tropospheric centers of rotation. Increasing the initial displacement of rotational centers (the tilt) from a negligible value to several hundred kilometers extends the time scale of hurricane formation from 1 to 10 days. Hindered amplification of the maximum tangential velocity υm at the surface of a strongly perturbed system is related to an extended duration of misalignment resulting from incomplete early decay and subsequent transient growth of the tilt magnitude. The prolonged misalignment coincides with a prolonged period of asymmetric convection peaked far from the surface center of the vortex. A Sawyer–Eliassen model is used to analyze the disparity between azimuthal velocity tendencies of selected pre–tropical storm vortices with low and high degrees of misalignment. Although no single factor completely explains the difference of intensification rates, greater misalignment is linked to weaker positive azimuthal velocity forcing near υm by the component of the mean secondary circulation attributed to heating by microphysical cloud processes. Of note regarding the dynamics, enhanced tilt only modestly affects the growth rate of kinetic energy outside the core of the surface vortex while severely hindering intensification of υm within the core for at least several days. The processes controlling the evolution of the misalignment associated with inefficient development are examined in detail for a selected simulation. It is found that adiabatic mechanisms are capable of driving the transient amplification of tilt, whereas diabatic processes are essential to ultimate alignment of the tropical cyclone.

A Mathematical Model Governing Tornado Dynamics: An Exact Solution of a Generalized Model

2018 ◽  
Vol 73 (8) ◽  
pp. 753-766
Author(s):  
Sanjay Kumar Pandey ◽  
Jagdish Prasad Maurya
Keyword(s):  
Reynolds Number ◽  
Radial Velocity ◽  
Quantitative Difference ◽  
Radial Pressure ◽  
Azimuthal Velocity ◽  
Large Reynolds Number ◽  
Axial Distance ◽  
Inviscid Flows ◽  
The Core ◽  
The Difference

AbstractWe investigate in this paper the dynamics of tornadoes by considering that the real inflow radial velocity depends on both the radial and vertical coordinates. The formulation is based on the model for the radial velocity that has been deduced from an experimentally verified model of azimuthal velocity. We present an analytical model for steady, incompressible, and viscous fluids and try for exact solutions. Although all the three components depend on radial and axial coordinates, viscosity affects merely the azimuthal velocity and the pressure. It is observed that the magnitude of the radial velocity increases to the maximum at the core but reverses the trend beyond and vanishes as it reaches the centerline. The magnitude reduces linearly with axial distance as per the supposition. At the core, the larger the Reynolds number, the lower is the velocity for moderate Reynolds numbers. Insignificant impact is observed for very large Reynolds number. However, inside and outside the core, the trends are reversed. Radial pressure distributions for different axial positions are similar to theoretical, numerical, and experimental observations. As we move outward from the axis, pressure increases. The difference between the pressures at the axis and that in outward regions increases with height. Pressure falls with rising Reynolds number uniformly for all radial distances. This is an indication that quantitative difference in pressure is large between viscous and inviscid flows.

The Intensity-dependence of Tropical Cyclone Intensification Rate in a Simplified Energetically Based Dynamical System Model

2021 ◽  
Author(s):  
Yuqing Wang ◽  
Yuanlong Li ◽  
Jing Xu ◽  
Zhe-Min Tan ◽  
Yanluan Lin
Keyword(s):  
Dynamical System ◽  
Tropical Cyclone ◽  
Inner Core ◽  
Surface Friction ◽  
Rate Of Change ◽  
System Model ◽  
Cloud Resolving Model ◽  
Thermodynamic Conditions ◽  
The Difference ◽  
Convective Organization

AbstractIn this study, a simple energetically based dynamical system model of tropical cyclone (TC) intensification is modified to account for the observed dependence of the intensification rate (IR) on the storm intensity. According to the modified dynamical system model, the TC IR is controlled by the intensification potential (IP) and the weakening rate due to surface friction beneath the eyewall. The IP is determined primarily by the rate of change in the potential energy available for a TC to develop, which is a function of the thermodynamic conditions of the atmosphere and the underlying ocean, and the dynamical efficiency of the TC system. The latter depends strongly on the degree of convective organization within the eyewall and the inner-core inertial stability of the storm. At a relatively low TC intensity, the IP of the intensifying storm is larger than the frictional weakening rate, leading to an increase in the TC IR with TC intensity in this stage. As the storm reaches an intermediate intensity of 30-40 m s-1, the difference between IP and frictional weakening rate reaches its maximum, concurrent with the maximum IR. Later on, the IR decreases as the TC intensifies further because the frictional dissipation increases with TC intensity at a faster rate than the IP. Finally, the storm approaches its maximum potential intensity (MPI) and the IR becomes zero. The modified dynamical system model is validated with results from idealized simulations with an axisymmetric nonhydrostatic, cloud-resolving model.

Spatial Convergence in Height in Central Europe, 1890-1910

2009 ◽  
pp. 90
Author(s):  
Marek Brabec ◽  
John Komlos
Keyword(s):  
Global Economy ◽  
Well Being ◽  
Habsburg Monarchy ◽  
The Core ◽  
Military Recruits ◽  
Convergence Clubs ◽  
Spatial Convergence ◽  
Physical Stature ◽  
The Difference ◽  
Peripheral Areas

We examine spatial convergence in biological well-being in the Habsburg Monarchy, circa 1890-1910, on the basis of evidence of the physical stature of 21-year-old military recruits, disaggregated into 15 Districts. We find that the shorter the population in 1890, the faster its height grew thereafter. Hence, there was convergence in physical stature between the peripheral areas of the monarchy (located in today’s Poland/Ukraine, Romania, and Slovakia) and its core (located in today’s Austria, Czech Republic, and Hungary). The difference in trends between the trend in height in the Polish District of Przemysl and in Vienna was about 0.9 cm per decade, in favor of the former. Convergence among the core Districts themselves was minimal or non-existent, whereas the convergence among the peripheral Districts was more pronounced. Spatial convergence also took place between the peripheral regions and the more developed ones. The pattern is somewhat reminiscent of modern findings on convergence clubs in the global economy.

Gebruiksaspecten van het uitroeppartikel wat in het Nederlands en Fries

2020 ◽  
Vol 136 (4) ◽  
pp. 189-209
Author(s):  
Henk Wolf
Keyword(s):  
The Core ◽  
The Difference ◽  
Lexical Phrase ◽  
High Degree ◽  
Lexical Phrases

Abstract Both Dutch and (West) Frisian make use of the exclamative particle wat (‘how’), that adds an element of surprise about a high degree of something to the semantics of the sentence. In this paper I will first show the similarities between the use of the particle in the two languages. I will demonstrate that, in Dutch, its use is largely confined to constructions that are semantically scalable, whereas in Frisian this restriction is far less strict. I will explain the difference by showing that Dutch wat is a syntactic amplifier of lexical phrases, whereas Frisian wat has developed into a pragmatic amplifier of the core predicate. I will try to account for that difference by showing how homophonous words absent in Dutch are likely to have influenced the use of Frisian wat, and how Dutch prosody strengthens the connection between wat and the amplified lexical phrase, whereas Frisian prosody weakens it. Finally, I will show that the system described as ‘Frisian’ is occasionally found in varieties of Dutch too

scholarly journals A Triggering Mechanism for Rapid Intensification of Tropical Cyclones

2015 ◽  
Vol 72 (7) ◽  
pp. 2666-2681 ◽  
Author(s):  
Yoshiaki Miyamoto ◽  
Tetsuya Takemi
Keyword(s):  
Boundary Layer ◽  
Numerical Experiments ◽  
Axisymmetric Flow ◽  
Three Dimensional ◽  
Tangential Velocity ◽  
Convective Cell ◽  
Rapid Intensification ◽  
Rotating Fluid ◽  
Coriolis Parameter ◽  
Maximum Tangential Velocity

Triggering processes for the rapidly intensifying phase of a tropical cyclone (TC) were investigated on the basis of numerical experiments using a three-dimensional nonhydrostatic model. The results revealed that the rapid intensification of the simulated TC commenced following the formation of a circular cloud, which occurred about 12 h after the TC became essentially axisymmetric. The circular cloud (eyewall) evolved from a cloudy convective cell that was originally generated near the radius of maximum wind speed (RMW). The development of the convective cell in the eyewall was closely related to the radial location of the strong boundary layer convergence of axisymmetric flow. The radius of maximum convergence (RMC) was small relative to the RMW when the TC vortex was weak, which is consistent with the boundary layer theory for a rotating fluid system on a frictional surface. As the TC intensified, the RMC approached the RMW. An eyewall was very likely to form in the simulated TC when the RMC approached the RMW. Because the RMC is theoretically determined by a Rossby number defined by the maximum tangential velocity, RMW, and Coriolis parameter, a series of numerical experiments was conducted by changing the three parameters. The results were consistent with the hypothesis that intensification occurs earlier for larger Rossby numbers. This finding indicates that initial TC vortices with larger Rossby numbers are more likely to experience rapid intensification and, hence, to evolve into strong hurricanes.

scholarly journals A comparative analysis of differentially expressed mRNAs, miRNAs and circRNAs provides insights into the key genes involved in the high-altitude adaptation of yaks

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Qianyun Ge ◽  
Yongbo Guo ◽  
Wangshan Zheng ◽  
Yuan Cai ◽  
Xuebin Qi ◽  
...  
Keyword(s):  
High Altitude ◽  
Molecular Mechanisms ◽  
Regulation Of Gene Expression ◽  
Differentially Expressed ◽  
The Tibetan Plateau ◽  
The Core ◽  
Processing Pathways ◽  
Genetic Information Processing ◽  
Altitude Adaptation ◽  
The Difference

Abstract Background Yaks that inhabit the Tibetan Plateau exhibit striking phenotypic and physiological differences from cattle and have adapted well to the extreme conditions on the plateau. However, the mechanisms used by these animals for the regulation of gene expression at high altitude are not fully understood. Results Here, we sequenced nine lung transcriptomes of yaks at altitudes of 3400, 4200 and 5000 m, and low-altitude Zaosheng cattle, which is a closely related species, served as controls. The analysis identified 21,764 mRNAs, 1377 circRNAs and 1209 miRNAs. By comparing yaks and cattle, 4975 mRNAs, 252 circRNAs and 75 miRNAs were identified differentially expressed. By comparing yaks at different altitudes, we identified 756 mRNAs, 64 circRNAs and 83 miRNAs that were differentially expressed (fold change ≥2 and P-value < 0.05). The pathways enriched in the mRNAs, circRNAs and miRNAs identified from the comparison of yaks and cattle were mainly associated with metabolism, including ‘glycosaminoglycan degradation’, ‘pentose and glucuronate interconversions’ and ‘flavone and flavonol biosynthesis’, and the mRNAs, circRNAs and miRNAs identified from the comparison of yaks at different altitude gradients were significantly enriched in metabolic pathways and immune and genetic information processing pathways. The core RNAs were identified from the mRNA-miRNA-circRNA networks constructed using the predominant differentially expressed RNAs. The core genes specific to the difference between yaks and cattle were associated with the endoplasmic reticulum and fat deposition, but those identified from the comparison among yaks at different altitude gradients were associated with maintenance of the normal biological functions of cells. Conclusions This study enhances our understanding of the molecular mechanisms involved in hypoxic adaptation in yaks and might contribute to improvements in the understanding and prevention of hypoxia-related diseases.

scholarly journals Territorial organization of the restaurant facilities of Kyiv agglomeration

2015 ◽  
pp. 79-82
Author(s):  
K. Dmytriieva
Keyword(s):  
Restaurant Industry ◽  
The Core ◽  
Industry Standards ◽  
The Status ◽  
Territorial Organization ◽  
The Difference ◽  
Surrounding Areas ◽  
Concentration Ratios

The article outlines the factors of development of the restaurant facilities in Kyiv and surrounding areas. The status of the territorial organization of the restaurant facilities of Kyiv and Kyiv region through the review of the main indicators of the industry by districts in 2013 has been analyzed. Comparison of the industry standards due to availability of these services to population needs has been performed. The result of the difference of efficiency of the restaurant industry through calculation of concentration ratios turnover has been received. Area that can be considered as the core of the restaurant industry of Kyiv agglomeration and area with the potential of growth has been identified. The article visualized by maps.

Control of Shroud Leakage Loss by Reducing Circumferential Mixing

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Budimir Rosic ◽  
John D. Denton
Keyword(s):  
Significant Proportion ◽  
Tangential Velocity ◽  
Secondary Flows ◽  
Main Stream ◽  
Leakage Flow ◽  
Flow Angle ◽  
Blade Row ◽  
Stator Blade ◽  
The Difference ◽  
Mixing Losses

Shroud leakage flow undergoes little change in the tangential velocity as it passes over the shroud. Mixing due to the difference in tangential velocity between the main stream flow and the leakage flow creates a significant proportion of the total loss associated with shroud leakage flow. The unturned leakage flow also causes negative incidence and intensifies the secondary flows in the downstream blade row. This paper describes the experimental results of a concept to turn the rotor shroud leakage flow in the direction of the main blade passage flow in order to reduce the aerodynamic mixing losses. A three-stage air model turbine with low aspect ratio blading was used in this study. A series of different stationary turning vane geometries placed into the rotor shroud exit cavity downstream of each rotor blade row was tested. A significant improvement in flow angle and loss in the downstream stator blade rows was measured together with an increase in turbine brake efficiency of 0.4 %.

7. Terms of the contract I

2018 ◽  
Author(s):  
Janet O’Sullivan
Keyword(s):  
Contextual Approach ◽  
The Core ◽  
The Subject ◽  
The Difference

Titles in the Core Text series take the reader straight to the heart of the subject, providing focused, concise, and reliable guides for students at all levels. This chapter examines issues related to the terms of the contract. It explains the distinction between terms and mere representations, and analyses the difference between signed and unsigned contracts in relation to the incorporation of express. This chapter also considers the parol evidence rule and the modern contextual approach to contractual interpretation. Finally it considers implied terms, which can be implied by statute or by the courts.

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