scholarly journals A REVIEW ON TROPICAL CYCLONES

Author(s):  
Indrajit Ghosh

In this review, we have discussed the important recent theoretical research works on tropical cyclone dynamics. For mitigation of the devastating effect of tropical cyclones on coastal human civilization more and more advanced forecasting techniques are evolving nowadays with the increase in the frequency of generation of tropical cyclones. Thus it is of utmost necessity to understand the anatomy and physiology of the dynamics of tropical cyclones. So researchers explain the cyclonic system from a different point of view and that is highlighted in this review. So this review illustrates, in brief, some important developed models.

2018 ◽  
Vol 13 (13) ◽  
pp. 100-113
Author(s):  
Y.V., Netsvitay T. V. Tararoev

Background. Goals In recent years, there is a growing interest in musical thinking, which is a key element of musicology and music philosophy, since music is a conscious, mental activity of a person and understanding the mechanisms of this activity, we can signifi cantly expand and deepen our understanding of music. The purpose of this study is to defi ne and supplement and clarify the concept of M. G. Aranovsky musical thinking our author’s approach, concretizing and clarifying the methodological and heuristic function of symmetry in musical thinking and its anthropological content. The work uses methods of comparison, analysis and synthesis. Musical thinking manifests itself in three forms of basic musical activity - composing, performing, listening, to which we also add theoretical (research) and pedagogical They are based on the processes of musical thinking and the fulfi llment of certain goals: the creation of an artifact, interpretation, reproduction, perception, analysis and theoretical understanding. The three spheres of realization of musical thinking are emotional-sensual, rational-logical and textual, semantic. These forms are closely intertwined and function on the basis of musical language, which is the foundation of any musical creative activity. The direct interaction of music and rationality is displayed in terms of “musical logic” and “architectonic musical ear”. Logic is the science of the most common laws of thought. These laws of thinking are expressed in the most abstract forms, patterns, rules that can be interpreted as conformity of something to specifi c norms, patterns. With regard to music, logic implies following certain standards and rules. Since the rational principle in music is closely associated with the irrational unconscious, the common logical norms that have been formed in a certain historical epoch within the framework of the dominant system of musical language are refracted through the individual stylistic features of the composer. A specifi c type of thinking - musical - generates the corresponding type of logic. Therefore, it is possible to express musical thinking by the sum of concepts - musical logic, musical speech and semantics of musical speech. M. G. Aranovsky identifi es four layers of musical logic: combinatorial, linguistic, contextual and artistic, i.e. those aspects (levels, edges) of the creative activity of a musician, in which there is logic. The lowest and at the same time fundamental level of musical logic is combinatorial, it is the sphere of primary elementary logical combinations of the simplest elements. However, the logic of this level extends to all scales of structures, from small motive links to sections of a one-part form. M. G. Aranovsky proposes to distinguish three types of logical combinations: 1. Identical - based on a constant repetition of structural units, where the formed elements are identical with each other (for example, AAAAAA). In terms of symmetry, this is a transformation of a simple movement along the time axis. It can again be noted as the simplest type of isomorphism, where only one characteristic changes - temporary. If we exclude it from consideration, then we can say that this is a “degenerate case” of isomorphism, which is an automorphism. 2. Equivalent - based on the modifi ed version of the repetition, in which there are both similarities and differences, i.e. incomplete identity is formed (for example, A1A2A3A4). From the point of view of symmetry, this combination of sequences represents the “unity” of the operation of symmetry, movement and violation of symmetry as such, i.e. in this sequence, some properties are repeated, while others change. This temporal process can be represented as isomorphism in the proper sense of the word, when some elements remain identical, while others change, and in general the objects are different, but similar. 3. Alternative - a combination of sequences of different units with complete exclusion of formal or obvious similarity (for example, ABC). Through symmetric transformations, this kind of logical combinations of primary elements can be described as an even greater symmetry violation, which preserves only the general “sequence of elements”, i.e. a small number of common properties, while these elements themselves are significantly different from each other. In this case, one can speak of a deep “transformation” of isomorphism, which can be called “metamorphism” (gr. Metamorphoómai - transformation of form). The basis of this transformation is a violation of the original symmetry in such a way that much more properties change than in the case of isomorphism. It can be schematically represented as A1 → B, A2 → C, etc. Thus, metamorphism can be considered both as a similarity, which has undergone a rather strong transformation, and as a symmetry violation, leading to a signifi cant complication of the structure. Thus, the result of this study is the position that, from the point of view of M. G. Aranowsky, the temporal process is the basis of musical thinking. The built-up chain “temporal process → musical logic → musical thinking” is the anthropological specifi city of human thought (in the musical sphere) associated with temporal processes in which a person is “immersed” and from which he cannot “exit” under any circumstances. Findings. we conclude that this chain can be called the “temporal-anthropological triad”. It represents the sequence “automorphism → isomorphism → metamorphism”. Each of its stages is different from the previous increase in the level of complexity. Of particular interest is the transition from isomorphism to metamorphism, since it is associated with the process of symmetry breaking. The mechanisms and principles of this disorder need further investigation.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Hamish Steptoe ◽  
Nicholas Henry Savage ◽  
Saeed Sadri ◽  
Kate Salmon ◽  
Zubair Maalick ◽  
...  

AbstractHigh resolution simulations at 4.4 km and 1.5 km resolution have been performed for 12 historical tropical cyclones impacting Bangladesh. We use the European Centre for Medium-Range Weather Forecasting 5th generation Re-Analysis (ERA5) to provide a 9-member ensemble of initial and boundary conditions for the regional configuration of the Met Office Unified Model. The simulations are compared to the original ERA5 data and the International Best Track Archive for Climate Stewardship (IBTrACS) tropical cyclone database for wind speed, gust speed and mean sea-level pressure. The 4.4 km simulations show a typical increase in peak gust speed of 41 to 118 knots relative to ERA5, and a deepening of minimum mean sea-level pressure of up to −27 hPa, relative to ERA5 and IBTrACS data. The downscaled simulations compare more favourably with IBTrACS data than the ERA5 data suggesting tropical cyclone hazards in the ERA5 deterministic output may be underestimated. The dataset is freely available from 10.5281/zenodo.3600201.


2015 ◽  
Vol 143 (3) ◽  
pp. 878-882 ◽  
Author(s):  
Roman Kowch ◽  
Kerry Emanuel

Abstract Probably not. Frequency distributions of intensification and dissipation developed from synthetic open-ocean tropical cyclone data show no evidence of significant departures from exponential distributions, though there is some evidence for a fat tail of dissipation rates. This suggests that no special factors govern high intensification rates and that tropical cyclone intensification and dissipation are controlled by statistically random environmental and internal variability.


2012 ◽  
Vol 27 (3) ◽  
pp. 757-769 ◽  
Author(s):  
James I. Belanger ◽  
Peter J. Webster ◽  
Judith A. Curry ◽  
Mark T. Jelinek

Abstract This analysis examines the predictability of several key forecasting parameters using the ECMWF Variable Ensemble Prediction System (VarEPS) for tropical cyclones (TCs) in the North Indian Ocean (NIO) including tropical cyclone genesis, pregenesis and postgenesis track and intensity projections, and regional outlooks of tropical cyclone activity for the Arabian Sea and the Bay of Bengal. Based on the evaluation period from 2007 to 2010, the VarEPS TC genesis forecasts demonstrate low false-alarm rates and moderate to high probabilities of detection for lead times of 1–7 days. In addition, VarEPS pregenesis track forecasts on average perform better than VarEPS postgenesis forecasts through 120 h and feature a total track error growth of 41 n mi day−1. VarEPS provides superior postgenesis track forecasts for lead times greater than 12 h compared to other models, including the Met Office global model (UKMET), the Navy Operational Global Atmospheric Prediction System (NOGAPS), and the Global Forecasting System (GFS), and slightly lower track errors than the Joint Typhoon Warning Center. This paper concludes with a discussion of how VarEPS can provide much of this extended predictability within a probabilistic framework for the region.


Author(s):  
N. B. Gubergrits ◽  
N. V. Byelyayeva ◽  
K. Y. Linevska

For over a thousand years, Hippocrates and Galen have been the Alpha and Omega of medical knowledge. Despite the importance of their contributions to clinical and theoretical medicine, they lacked a true understanding of anatomy and physiology. Hippocrates is commonly associated with proposing the doctrine of «tissue fluids», or humoral pathology, and his book, «On the Nature of Man», promotes this point of view. Galen became inherited the knowledge of Hippocrates. Ultimately, he was recognized as one of the most influential physicians of all time. The number of his works was enormous: he wrote more than a hundred books, which were widely distributed. One of Galen’s main commandments was the rule of harmony: all body systems are balanced; disease is a result of an imbalance. As one might expect, some of his ideas, however, were erroneous. Aristotle considered the pancreas, due to its location in the abdominal cavity, as an organ which only task was to protect the adjacent vessels. In an era when unknown diseases wreaked havoc, the concept of known causes of diseases led to the fascination with the study of food poisons and their antidotes. This was common among aristocracy who felt particularly vulnerable to this kind of threats. According to legend, one of the most famous connoisseurs of poisons was Mithridates VI. Pedanius Dioscorides was a Greek who served in the Roman army during the reign of the emperor Nero. The wandering nature of life led him to study a large number of diseases and medicines. The catalogue of his medicinal herbs and plants became the basis for the study and understanding of the medicinal properties of plants. Liver was considered the source of divine prophecy in many ancient cultures. The anatomy of liver was well known in ancient Babylon: a huge number of clay tablets and objects were left, which testify to the importance of «hepatoscopy» in the Middle East as a form of prediction. Those who used the insides of animals for divination (e.g., haruspices — divine interpreters of the future, using the liver as a prediction tool), could be considered the first official anatomists, since the understanding of the future depended on accurate knowledge and interpretation of certain liver components. After the victory of the Assyrian king Sargon over the forces of Urartu and Zikirti in 718 BC, Sargon wanted to appease the gods by sacrificing animals; in doing so, he studied their livers for predictions. Although the concept of pancreas is rooted in ancient times, as evidenced by the comments of haruspices and priests, knowledge of the organ functions eluded humanity until the works by Danish physiologists Francis Sylvius and Regnier de Graaf. Prior to their studies of pancreatic secretion and the elucidation of the role of pancreas in digestion, described by van Helmont and Albrecht von Haller, most researchers focused on the anatomical description of the organ. If the ancient Assyrians and Mesopotamians did not believe that liver predicts the future, but believed that it was pancreas that did it, then pancreatology may have earlier origins. Maimonides, a Jewish scholar and humanist, was also influential in other fields: he condemned astrology and its attempts to calculate the time of the Messiah’s coming. In the field of medicine, he paid attention to prevention, and was interested in the treatment of diseases of the gastrointestinal tract. By the beginning of our era, ideas about digestion, diseases of the digestive tract and their treatment remained very vague. There was a long and difficult way ahead in this area.  


2007 ◽  
Vol 135 (4) ◽  
pp. 1195-1207 ◽  
Author(s):  
Timothy F. Hogan ◽  
Randal L. Pauley

Abstract The influence of convective momentum transport (CMT) on tropical cyclone (TC) track forecasts is examined in the Navy Operational Global Atmospheric Prediction System (NOGAPS) with the Emanuel cumulus parameterization. Data assimilation and medium-range forecast experiments show that for 35 tropical cyclones during August and September 2004 the inclusion of CMT in the cumulus parameterization significantly improves the TC track forecasts. The tests show that the track forecasts are very sensitive to the magnitude of the Emanuel parameterization’s convective momentum transport parameter, which controls the CMT tendency returned by the parameterization. While the overall effect of this formulation of CMT in NOGAPS data assimilation/medium-range forecasts results in the surface pressure of tropical cyclones being less intense (and more consistent with the analysis), the parameterization is not equivalent to a simple diffusion of winds in the presence of convection. This is demonstrated by two data assimilation/medium-range forecast tests in which a vertical diffusion algorithm replaces the CMT. Two additional data assimilation/medium-range forecast experiments were conducted to test whether the skill increase primarily comes from the CMT in the immediate vicinity of the tropical cyclones. The results show that the inclusion of the CMT calculation in the vicinity of the TC makes the largest contribution to the increase in forecast skill, but the general contribution of CMT away from the TC also plays an important role.


2018 ◽  
Vol 1 (1) ◽  
pp. 597-604
Author(s):  
Wiktor Filipek ◽  
Krzysztof Broda

Abstract In recent years, we have observed a great interest in the exploitation of marine deposits by various methods of mining and transport to the surface. However, obtaining natural resources deposited at greater depths such as polymetallic nodules and seafloor massive sulphides – SMS creates a lot of challenges for both scientists and engineers. The solutions developed so far, unfortunately, have so far been characterized by high energy consumption. For several years the authors have been conducting theoretical and experimental research on new concepts of seabed to surface transport. The results of them have been presented in previous publications. This publication presents the results of the continuation of research on the concept of construction and operation of an autonomous transport module (submitted for printing). It focuses on a theoretical analysis of the change in gas phase density in the processes occurring during operation of the transport module intended for transport from the seabed. For this purpose, a reduced form of the van der Waals equation was used in the form of a third-degree equation for parameters interested from the point of view of the transport module.


2018 ◽  
Vol 6 (4) ◽  
pp. 5-13
Author(s):  
Mahtab Jafari

Each government consists of two dimensions: 1) a sructural dimension that involves policy- and decision-making bodies and, 2) a functional dimension that is a set of government institutions and administrations. Also, national authority in a country is an outcome of three components, including legitimacy, acceptance, and efficiency of its government. The authority of governments is not merely limited to their structural legitimacy and acceptance; but, their functional dimension and the performance of their administrations also play a crucial role in building and strengthening their legitimacy. Therefore, the aim of the present study is to investigate how the administrative system of a government affects its national authority, with an emphasis on the Islamic point of view. To do so, this research has been carried out within the framework of theoretical research with practical purpose. The research method of the current study was descriptive-analytical. In the present study, the relationship between two variables – namely, “administrative system” and “national authority”– has been investigated within the framework of causal research. Due to the theoretical nature of this study, the resources used mostly include documents and library resources. The results of this study indicate that there is a direct and causal relationship between the national authority of governments (effect) and the performance of their administrative system (cause). Also, this relationship reveals how the administrative system affects national authority.


Sign in / Sign up

Export Citation Format

Share Document