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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 18:16 |
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Conference: Bucharest University Faculty of Physics 2017 Meeting
Section: Atmosphere and Earth Science; Environment Protection
Title:
Gravity waves of orographic source over Romanian territory - conceptual approach proposals
Authors:
Octavian Paul BUGEAC (1,2)
*
Affiliation:
1) University of Bucharest, Faculty of Physics
2) Romanian air traffic services Administration
E-mail
paul.bugeac@gmail.com
Keywords:
Mountain Waves, Conceptual model, Breaking waves
Abstract:
Gravity waves are oscillations around dynamic stable status of the flow under the action of gravity and a return mechanism. They are a well-known source of aviation hazards, such as strong up- and down-drafts, downslope windstorms, clear air turbulence associated with tropospheric wave breaking, low-level turbulence and “rotors” associated with wave-induced boundary layer separation. In the study of orographic perturbation the oscillation is given by gravitation and the return is due to buoyancy in hydrostatic stability, determining the flow to have the character of a quasi-stationary wave. The present research is studying two special cases, namely the sustained orographic waves (Mountain Waves) and the orographic descent (Breaking Waves), proposing corresponding conceptual models for nowcasting associated hazards. In the study were used observation data (SYNOP and upper-air), model data and satellite imagery in infrared and visible spectral channels.The conceptual approach is essential in forecasting orographic events taking into account the complex computations necessary and the low density of synoptic and upper-air data. Also, Romanian topography being extremely complex, it makes numerical modelling very difficult. In this context, satellite information becomes essential in nowcasting orographic events. The impact on flight operations is major and can be in the range between light shakings up to structural damage due to severe turbulence and strong updraughts. In landing procedures, depending on the ascending or descending side of the wave, mountain waves can determine a “miss” or a bumpier landing and, in extreme cases, even structural damage. The products in aviation meteorology dealing with location and intensity of orographic waves are the significant weather charts and the warning messages SIGMET and AIRMET.Regarding the actuality of orographic wave impact, there are quoted some reports and investigations of specialized national agencies from Europe and USA of aviation accidents in which mountain waves had a decisive impact.
Acknowledgement:
Special thanks to Prof. Dr. Sabina Stefan for all support and guidance
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