anti-vortex Windmetingen Gustiness & vortex compensation

anti-vortex Variabele en positie Windsnelheid (FF) en –richting. (DD) o.a. bij TDZ, op 105 m van de centre line, h = 10 m sensor meetonzekerheid: FF: 0,5 m/s DD: 3° Annex 3, operational-desirable accuracy: FF: 0,5 m/s (< 5 m/s); 10% DD: 10° sample frequency: FF: 4 Hz DD: 75 Hz

anti-vortex Regelgeving waarnemingen, reports & displays Conform ICAO Annex 3 Annex 3 – App. 3 ICAO Doc (2004) – App.5 Manual of Aeronautical Meteorological Practice WMO-No. 731 Guide on Meteorological Observing and Information Distribution Systems for Aviation Weather Services WMO-No. 8 Guide to Meteorological Instruments & Methods of Observation

anti-vortex Regelgeving waarnemingen, reports & displays ICAO ANNEX Surface wind The mean direction and the mean speed of the surface wind shall be measured, as well as significant variations of the wind direction and speed (…) Recommendation. — When local routine and special reports are used for departing aircraft, the surface wind observations for these reports should be representative of conditions along the runway; when local routine and special reports are used for arriving aircraft, the surface wind observations for these reports should be representative of the touchdown zone. Surface wind observations for local routine and special reports should be representative of conditions at a height of approximately 10 m (30 ft) above the runway. Appendix Displays Averaging The averaging period for surface wind observations shall be: a) 2 minutes for local routine and special reports and for wind displays in air traffic services units; and b) 10 minutes for reports in the METAR/ and SPECI code forms (…).

anti-vortex Regelgeving waarnemingen, reports & displays Recommendation.— The averaging period for measuring variations from the mean wind speed (gusts) reported in accordance with c) should be 3 seconds for local routine and special reports and for METAR and SPECI Reporting In local routine reports and METAR and SPECI:, c) variations from the mean wind speed (gusts) during the past 10 minutes shall be reported when the maximum wind speed exceeds the mean speed by 20 km/h (10 kt) or more In local routine and special reports:, d) when variations from the mean speed (gusts) are reported in accordance with c) above, they shall be reported as the maximum and minimum values of the wind speed attained

anti-vortex Regelgeving waarnemingen, reports & displays ICAO Doc. 8876: In reports disseminated locally at the aerodrome, surface wind should be based on an averaging period of 2 minutes In reports in the METAR code form, surface wind should be based on an averaging period of 10 minutes Variations of wind direction and speed given in meteorological reports always refer to the 10-minute period preceding the observation. When the wind is gusty, with variations from the mean wind speed (gusts) exceeding 20 km/h (10 kt), speed variations are indicated. WMO-No. 731 A gusty wind is characterized by rapid fluctuations in wind direction and speed. At aerodromes, gustiness is specified by the extreme values of wind direction and speed between which the wind has varied during the last 10 minutes.

anti-vortex Regelgeving waarnemingen, reports & displays Voorschrift wat en hoe zal/zou moeten worden gerapporteerd (of getoond): Average windspeed: 2 min. avg.) Variations (gusts): 3 s avg. To be representative along the RWY (Take off), at the TDZ (landing)

anti-vortex History anti-vortex policy

anti-vortex History anti-vortex policy Okt nota i.a.a. HSPL (n.a.v. resultaten nieuwe meetlocaties), met vier oplossingen: 1. verplaatsen, 2. algorithme, 3. back-up WP (voor take-off) of 4. geen actie. April 1996 nota i.a.a. RLD, twee oplossingen: 1. back-up of 2. algorithme (d.w.z. aanpassing bij detectie fortex) Instantaan (beperkte reductie) Met vertraging van ca. 30 – 60 s (optimaal) Febr nota implementatie algorithme (beperkte reductie)

anti-vortex anti-vortex algorithme: theorie FF12” FF10’ ( FF12” – FF10’)/  FF10’

anti-vortex anti-vortex algorithme: theorie

anti-vortex anti-vortex algorithme: theorie Voor MAX(FF(3”); 12”) = FX12 : als FX12” > FF10’ + 5 σ FF10’ dan FX12”  FF10’ + 2,5 σ FF10’ reductie Om praktische redenen echter: als FX12” > FF10’ + 4 σ FF10’ + 0,5 m/s en FX12” 0,5 m/s, σ FF10’ > 0,5 m/s dan FX12”  FF10’ + 2 σ FF10’ + 0,5 m/s

anti-vortex anti-vortex algorithme: theorie FF10’ FX12” 12 Reductie, instantaan

anti-vortex anti-vortex algorithme De meting zelf is correct en de vraag is of kunstmatige impacts mogen worden weggefilterd (lokale windklimaat wordt beinvloed door de vortexen bij veel 747’s) – reductie lijkt redelijk compromis Reductie, geen verwijdering (bijv. FF10’ i.p.v. FX12”) Safety first, geen risico: natuurlijke variaties mogen nooit verwijderd worden Instantane filtering, dus niet achteraf Geen processing delay Verwijdering (correctie) alleen achteraf mogelijk

anti-vortex