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Eddies are known to be affected by typhoons, and in recent years, the general three-dimensional structure, as well as features of the spatial and temporal distributions of eddies have been determined. However, the type of eddy that is most likely to be affected by a typhoon remains unclear. In this paper, quantitative and qualitative methods were used to study the eddies that are most sensitive to upper-ocean tropical cyclones (TCs) from the perspective of eddy characteristics, and the quantitative results showed that not all eddies were enhanced under the influence of typhoons. Enhancement of the eddy amplitude (Amp), radius (Rad), area (A), or eddy kinetic energy (EKE) accounted for 92.3% of the total eddy within the radius of the typhoon. Qualitative analyses showed the following: First, eddies located on different sides of the typhoon tracks were differently affected, as eddies on the left side were more intensely affected by the typhoon than eddies on the right side, and second, eddies with short lifespans or small radii were more susceptible to the TCs.
Based upon the true voyages various methods of avoidance maneuver determination in ship - cyclone encounter situations were presented. The goal was to find the economically optimal solution (minimum fuel consumption, maintaining the voyage schedule) while at the same time not to exceed an acceptable weather risk level.
Satellite navigation gains importance in sustainable development of modern civilisation. With the increasing number of GNSS-based technology and socio-economic systems and services, satellite navigation has become an essential component of national infrastructure. This calls for novel requirements on GNSS positioning perfomance, and increasing need for resilient GNSS development. Here we examined the impact of rapidly developing tropical cyclone on GPS positioning performance degradation, and the resulting impact on oceanic non-navigation and navigation GPS applications. We presented the methodology for indirect simulation-based GPS positioning performance evaluation through utilisation of experimental GPS observations, GNSS Software-Defined Radio (SDR) receiver, and a statistical analysis and framework we developed in the R environment for scientific computing. We identified alteration of GPS positioning error components time series statistical properties, and discuss the potential impact on GPS-based services essential for remote oceanic island communities. Manuscript concludes with the summary of findings, proposal for recommendations on improved GNSS resilience, and an outline for future research.
Content available remote Elements of Tropical Cyclones Avoidance Procedure
The updated version of the Cyclone II program was used for analyzing hundreds of cases where ships were facing dozens of developed cyclones. The program generates directions for navigators that are recommended for consideration before making decisions on passing around or avoiding tropical cyclones. Three specific situations were defined where a vessel may enter the area affected by a tropical cyclone, and its commander must consider three recommendations for safe passing of the cyclone: – vessel – cyclone encounter, where if on opposite course, the most effective is course alteration; – when the ship overtakes the cyclone, speed reduction is the most effective action; – when the vessel and the cyclone are on crossing routes (30 ÷ 90°), a slight decrease in speed or a slight course alteration or both actions can be effective.
Zaprezentowano obliczenia wyboru najkorzystniejszej trasy statku na oceanie z uwzględnieniem omijania cyklonów tropikalnych na Północnym Atlantyku. Testowania wykonano dla podróży statku m/v "Daszyński" w rzeczywistych warunkach pogodowych od 26.09.2004 r. do 6.10.2004 r., gdy na Atlantyku Północnym wystąpiły cyklony "Jeanne" i "Lisa". Zastosowano program obliczeniowy wykorzystujący algorytmy ewolucyjne.
The most beneficial ship's route calculations on the ocean are presented, taking into consideration tropical cyclone avoidance. Tests were made for the m/v "Daszynski" voyage using real weather data during 26.IX.04 - 06.X.04, when the North Atlantic was haunted by the tropical cyclons "Jeanne" and "Lisa". A computational program based on evolutional algorithms was used.
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