Aviation Weather Hazards Mitigation related to Wake-Vortex & Convective Storm Encounters.


Frédéric Barbaresco (Thales Air Systems - Limours)

en collaboration avec C. Costes & J.P. Artis
Most of weather delays & accidents could be avoided by new advanced weather advisory, nowcasting and forecasting system in and around the airport terminal area & by dispatching weather information and alerts to Air Traffic Controller and on Pilot's Cockpit Display. Among weather hazards, wake-vortex & convective storm Mitigation could drastically improve jointly Airport Safety and Capacity.

Wake vortices are a natural by-product of lift generated by aircraft and can be considered as two horizontal tornados trailing after the aircraft. A trailing aircraft exposed to the wake vortex turbulence of a lead aircraft can experience an induced roll moment that is not easily corrected by the pilot or the autopilot. This limiting factor will be significantly accentuated soon with the arrival of new heavy aircrafts: Airbus A380 and the new stretched version of Boeing B747-8. However these distances can be safely reduced with the aid of smart planning techniques of future Wake Vortex Advisory Systems based on all weather Radar/Lidar Wake Vortex Monitoring Sensors and Wake Vortex Predictors. Main Wake Vortex Predictor inputs requirement is high time/space accuracy wind assessment in and around terminal area. We present international state-of-the art in the domain of wake-vortex monitoring and wake-vortex predictor.

Weather channel of Primary Surveillance ATC radar and airborne weather radars on civil aircrafts provide real-time information on convective clouds. Such convective storm is typically composed of numerous clouds, which are likely to advect, merge, split and/or collapse. The pilot must choose a route, taking into account relative position, intensity of convection, trajectory and life cycle of each cloud. These considerations lead to analyse description models which synthesize useful information, in order to transmit a small amount of data on ground-air and air-air links. Moreover, the forecasting task must be based on robust parameters, describing convective clouds evolution in term of horizontal motions, vertical tendency, and dynamic behavior: merging, splitting, convection intensity, etc. In order to improve the decision-making process, a method for tracking and nowcasting clouds motions is presented based on mathematical morphological skeletons and graph matching optimization. Binary or greyscale skeletons are interesting shape descriptor, especially for fluid shapes tracking, and results will be illustrated on ATC PSR radar and airborne weather radar data.

References :
[1] Wakenet-3 Europe, "Wake Turbulence Safety in Future Aircraft Operations", 1rst Plenary Wakenet-3 Workshop, Thales University, Jouy-en-Josas, 8th & 8th Jan. 2010, web : http://www.wakenet3-europe.eu/index.php?id=63
[2] Wakenet-3 Europe, "Wake Vortex & Wind Monitoring Sensors In All Weather Conditions", Wakenet-3/Greenwake Dedicated Workshop, Thales Research & Technology, Palaiseau, 29th & 30th March 2010, web : http://www.wakenet3-europe.eu/index.php?id=21
[3] F. Barbaresco & U. Meier, "Imagerie Radar des tourbillons de sillage : Réflexion électromagnétique des turbulences de sillage en air clair", Comptes rendus Physique de l'Académie des Sciences, Elsevier Masson SAS, 2010
[4] F. Barbaresco & U. Meier, "Wake Vortex X-Band Radar Monitoring: Paris-CDG Airport 2008 Campaign Results and Prospectives", International Radar Conference, Bordeaux, Oct. 2009
[5] F. Barbaresco, "Airport Radar Monitoring of Wake Vortex in all Weather Conditions", International Radar Conference, Bordeaux, Oct. 2009
[6] G. Winckelmans, F. Barbaresco, Et Al , "The ATC-Wake Predictor system and its potential use to increase the capacity at airports", In: Proc. Joint International Symposium on Sensors and Systems for Airport surveillance, JISSA 2005, Paris, June 20-21, 2005
[7] L.J.P. Speiker, A. Vidal, F. Barbaresco, M. Frech, H. Barny, G. Winckelmans, "ATC-Wake : Integrated Wake Vortex Safety and Capacity System", The Journal of Air Traffic Control, vol.49, n°1, 2007, pp.17-32.
[8] V. Treve, G. Winckelmans, T. Duquesne, L. Bricteux, "Description of the VFS, and VFS results on the benchmark for wake vortices IGE", Proc. Joint WakeNet-USA and WakeNet2-Europe Workshop on the Prediction of Wake Vortices in Ground Effects in an Operational Context, New Orleans, LA, April 27-29, 2004, 2004
[9] G. Winckelmans, R. Cocle, L. Dufresne, R. Capart, L. Bricteux, G. Daeninck, T. Lonfils, M. Duponcheel, O. Desenfans, L. Georges, "Direct numerical simulation and large-eddy simulation of wake vortices : going from laboratory conditions to flight conditions", Proc. European Conference on Computational Fluid Dynamics (ECCOMAS CFD 2006), Special Technology Session on Wake Vortex Research in Europe, Egmond aan Zee, The Netherlands, 5-8 Sept. 2006
[10] C. Costes & J.P. Artis, "Weather Hazard Interpretation and Forecast by an Airborne Radar", International Radar Conference, Bordeaux, Oct. 2009
[11] C. Costes, J.P. Artis & F. Barbaresco, "Advanced Clouds Tracking for Airborne Weather Radar & Ground Primary Surveillance Radar", submitted to EURAD'10, Paris, Sept. 2010
[12] C. Costes, "Modélisation, pistage et prédiction d'une situation météorologique vue par un radar séroporté", thèse Télécom Bretagne, Janvier 2010
[13] F. Barbaresco & B. Monnier, "Rain Clouds Tracking with Radar Image Processing Based on Morphological Skeleton Matching, in IEEE Trans. Image Processing, vol. 1, oct 2001, pp. 830-833.
[14] S. Fernandez-Vidal & G. Malandain, "Squelettes euclidiens d’objets discrets n-dimensionnels", INRIA, Sophia-Antipolis, France, jan 1996


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