Work Package 1: Final Project Report Appendix E: The METAR data

Work Package 1: Final Project Report Appendix E: The METAR data First Assessment of the operational Limitations, Benefits & Applicability for a List of package I AS applications FALBALA Project Drafted by: Philippe Louyot Authorised by: Thierry Arino on 16-04-04 ADDRESSEES: Francis Casaux (CARE/ASAS Manager), Mick Van Gool (CARE Manager), Bogdan Petricel (AGC Programme), Costas Tamvaclis (ADS Programme) COPY TO: CENA, DFS, EEC, NATS, UoG & Sofréavia Participants Page E-1/32

RECORD OF CHANGES Issue Date Detail of changes 0.1 4 th September 2003 Initial draft 0.2 17 th November 2003 All sections completed 1.0 19 th March 2004 Proposed first issue of the Appendix 1.1 16 th April 2004 Editorials in the front pages IMPORTANT NOTE: ANY NEW VERSION SUPERSEDES THE PRECEDING VERSION, WHICH MUST BE DESTROYED OR CLEARLY MARKED ON THE FRONT PAGE WITH THE MENTION OBSOLETE VERSION Page E-2/32

TABLE OF CONTENTS E1. INTRODUCTION... 5 E2. EUROPEAN METAR RECORDINGS... 6 E2.1. METAR DATA CARACTERISTICS... 6 E2.2. SOURCES OF METAR DATA AND ASSOCIATED PERIOD... 6 E2.3. METAR CONTENT... 7 E3. METAR DECODING AND PRESENTATION... 8 E3.1. SELECTED PARAMETERS... 8 E3.2. SELECTED AIRPORTS... 8 E3.3. GLOBAL PRESENTATION... 8 E3.3.1. General... 8 E3.3.2. Wind distribution presentation... 9 E3.3.3. Visibility and weather phenomena presentation... 9 E3.3.4. Ceiling presentation...10 E3.3.5. QNH presentation...11 E4. AIRPORT WEATHER...12 E4.1. PARIS ORLY (LFPO)...12 E4.1.1. Wind distribution...12 E4.1.2. Visibility and weather phenomena...13 E4.1.3. Ceiling...14 E4.1.4. QNH...15 E4.2. PARIS CDG (LFPG)...16 E4.2.1. Wind distribution...16 E4.2.2. Visibility and weather phenomena...17 E4.2.3. Ceiling...18 E4.2.4. QNH...19 E4.3. LONDON HEATROW (EGLL)...20 E4.3.1. Wind distribution...20 E4.3.2. Visibility and weather phenomena...21 E4.3.3. Ceiling...22 E4.3.4. QNH...23 E4.4. LONDON GATWICK (EGKK)...24 E4.4.1. Wind distribution...24 E4.4.2. Visibility and weather phenomena...25 E4.4.3. Ceiling...26 E4.4.4. QNH...27 E4.5. FRANKFURT (EDDF)...28 E4.5.1. Wind distribution...28 E4.5.2. Visibility and weather phenomena...29 E4.5.3. Ceiling...30 E4.5.4. QNH...31 E5. REFERENCES... ERREUR! SIGNET NON DEFINI. E6. ACRONYMS...32 Page E-3/32

LIST OF FIGURES Figure 1: Wind distribution presentation icon... 9 Figure 2: Visibility and weather phenomena presentation icon... 9 Figure 3: Ceiling presentation icon...10 Figure 4: QNH presentation icon...11 Figure 5: Wind distribution at LFPO...12 Figure 6: Visibility and weather phenomena at LFPO...13 Figure 7: Ceiling at LFPO...14 Figure 8: QNH at LFPO...15 Figure 9: Wind distribution at LFPG...16 Figure 10: Visibility and weather phenomena at LFPG...17 Figure 11: Ceiling at LFPG...18 Figure 12: QNH at LFPG...19 Figure 13: Wind distribution at EGLL...20 Figure 14: Visibility and weather phenomena at EGLL...21 Figure 15: Ceiling at EGLL...22 Figure 16: QNH at EGLL...23 Figure 17: Wind distribution at EGKK...24 Figure 18: Visibility and weather phenomena at EGKK...25 Figure 19: Ceiling at EGKK...26 Figure 20: QNH at EGKK...27 Figure 21: Wind distribution at EDDF...28 Figure 22: Visibility and weather phenomena at EDDF...29 Figure 23: Ceiling at EDDF...30 Figure 24: QNH at EDDF...31 LIST OF TABLES Table 1: Weather phenomena and descriptors abbreviations 10 Table 2: Ceiling abbreviations 10 Page E-4/32

E1. INTRODUCTION E1.1. This working paper, which is developed within the context of Work Package (WP1): Current situation analysis Airspace perspective, describes the METAR (Meteorological Aerodrome Report) processing. E1.2. As a preliminary step before the analysis of the current situation (from both the airspace and the single aircraft perspective), this METAR data processing aims at identifying the different weather conditions on the principal airports considered within the FALBALA study, i.e. for each TMA: Frankfurt TMA: EDDF; London TMA: EGLL and EGKK; Paris TMA: LFPG and LFPO; E1.3. The METAR data gathering was achieved during a period similar to the Radar data recordings. The first week is only missing. E1.4. A METAR message describes the observed weather conditions on one airport and is provided by the meteorological services. E1.5. The intended uses of theses airport local weather observations are Runway configurations determination and eventual configuration changes detection for each day. Ceiling, visibility and weather phenomena analysis in order to guess the specific approach conditions, e.g. visual acquisition possibility or Category III approach. QNH knowledge for ground height or altitude calculation from flight level for further radar data processing. The QNH variation is also a good indicator of the general weather situation. E1.6. It has to noted that the possibilty to gather ATIS messages has been initially envisaged, but because of server access issue, it was decided not to use this path. The D- ATIS are only provided by ARINC. Page E-5/32

E2. EUROPEAN METAR RECORDINGS E2.1. METAR data caracteristics E2.1.1. A METAR is a periodic message describing the current weather conditions observed on an airport. E2.1.2. It is written in text format and its content is standardised by the WMO (World Meteorological Organization). E2.1.3. The METAR are renewed every 30 minutes for each airport. One METAR is relative to only one airport. E2.2. Sources of METAR data and associated period E2.2.1. The main part of the recorded METAR was provided by the NOAA server ("http://weather.noaa.gov/weather/) thanks to automatic and cyclic connexions from the CENA every 30 minutes. The recording started on 21 st July and stopped on 31 st August. The server connexion was unavailable from 2 nd August mid-day. August afternoon until the 4 th The recorded METAR are for the following airports: EDDF (Frankfurt) EGKK (London Gatwick), EGLL (London Heathrow) and EGSS (Stansted) LFPO (Paris Orly), LFPG (Paris Roissy) and LFPB (Le Bourget) E2.2.2. METAR recordings have also been provided by the NATS from on 4 th July until 29 th august for: EGKK, EGLL and EGSS E2.2.3. The METAR relative to 2 nd, 3 rd and 4 th July have been used to fill in the gap of the CENA recordings. E2.2.4. Unfortunately, the period between 15 th July and 21 st July is not available. So, all the available records start at the same date, i.e. the 21 st July. Page E-6/32

E2.3. METAR content E2.3.1. Example : LFPO 191100Z 18007KT CAVOK 27/12 Q1019 NOSIG LFPG 140630Z VRB08KT 340V200 4000 BR FEW050CB FEW053TCU SCT066 BKN260 20/17 Q1017 NOSIG E2.3.2. METAR includes the following information: Airport ICAO code Day and UTC time Wind: direction, strength, gust and sector then variable wind Visibility and RVR Weather phenomena Ceilings Temperatures QNH Tendency Page E-7/32

E3. METAR DECODING AND PRESENTATION E3.1. Selected parameters E3.1.1. The main goal is to provide a global view of the most important weather parameters for the whole recording period and for each main airport. Not all the METAR items are relevant. So, only a part of them have been extracted from the set of METAR. E3.1.2. The selected parameters are: The wind: Direction, strength and gusts. The horizontal visibility combined with the weather phenomena. The ceiling (octas cloud coverage and associated clouds base) The QNH (local barometric pressure at sea level) E3.2. Selected airports E3.2.1. As the weather was quite similar inside a same TMA, only the five main airports were retained, i.e: EDDF (Frankfurt) EGKK (London Gatwick), and EGLL (London Heathrow) LFPO (Paris Orly), and LFPG (Paris Roissy) E3.3. Global presentation E3.3.1. General E3.3.1.1. E3.3.1.2. E3.3.1.3. E3.3.1.4. The following section presents available METAR data over the whole recording period. There is one figure per each selected parameter and per airport. Each figure is a set of icon representing one day. This presentation allows to show the weather evolution and also to show the recording gaps. A line corresponds to a week beginning on Monday. The x-axis of the icons is the UTC time, except for the wind distribution icon which is a rho-theta representation. The weather phenomena are displayed on the visibility icon in order to reduce the number of figure and to simplify the mutual matching. This matching would have been better on the ceiling icon, but this icon is much more heavy than the visibility icon. The ceiling figure is the most adapted to detect quickly the good condition days. Page E-8/32

E3.3.2. Wind distribution presentation E3.3.2.1. The provenance and the strength wind are represented in rho-theta. In the following example, the wind is from South. Figure 1: Wind distribution presentation icon Note: The wind strength orthogonal full-scale is 15Kt. The gusts are drawn with a thin stroke. The runway orientations are drawn in cyan. All the wind data of a whole day are cumulated here. E3.3.3. Visibility and weather phenomena presentation E3.3.3.1. This icon shows the visibility combined with the weather phenomena. Figure 2: Visibility and weather phenomena presentation icon Note 1: The horizontal visibility full scale is 10km (Y axis). When the visibility is greater than 10 km, it is drawn at 10 km. Note 2: The x-axis starts at UTC 0, and is marked every 6 hours. Each weather phenomena is written with the left side of its tag corresponding to the time. The vertical dispatching is random. E3.3.3.2. E3.3.3.3. As the Runway Visual Range (RVR) items were infrequent during this recording period, they are not showed on this icon. However, the RVR items presence periods will be listed. Here is a list of the encountered abbreviation used for the weather phenomena. Some used tags are a combination of two basic abbreviations, e.g. SHRA or MIFG. Page E-9/32

BC BR DZ FG HZ MI RA SH TS VC Patches Mist Drizzle Fog Haze Shallow Rain Shower Thunderstorm Vicinity Table 1: Weather phenomena and descriptors abbreviations E3.3.4. Ceiling presentation E3.3.4.1. Below is a list of some abbreviations used for the ceiling conditions: FEW 1 or 2 octas (eighths) cloud coverage SCT Scattered 3-4 octas (eighths) cloud coverage BKN Broken 5-7 octas (eighths) cloud coverage OVC Overcast 8 octas (eighths) cloud coverage SKC Sky Clear NSC No significant cloud Table 2: Ceiling abbreviations E3.3.4.2. This icon shows the clouds coverage and its associated cloud base. The thinnest stroke matches to a FEW ceiling. The thickness increases gradually in relation to the octa: SCT, BKN and OVC. Then the ceiling is above 5000 feet (CAVOK or NSC), it is draw at 5000 feet with the thickest stroke. Figure 3: Ceiling presentation icon Note: As previously, the x-axis starts at UTC 0 and ends at 24. The ceiling full scale is 5000 feet, and the y-axis is marked every 1000 feet. Page E-10/32

E3.3.5. QNH presentation E3.3.5.1. This icon shows the actual QNH compared to standard barometric pressure. Figure 4: QNH presentation icon Note: The y-axis lowest value is 1000 hpa. The y-axis is marked every 10 hpa. The green mark matches to 1013 hpa. Page E-11/32

E4. AIRPORT WEATHER E4.1. PARIS ORLY (LFPO) E4.1.1. Wind distribution Figure 5: Wind distribution at LFPO The runway orientations are 064-244 and 076-256. The 02-20 is not drawn. Both landing configurations seem to be possible during this recording period. The westerly one is most probable in the end of July, whereas the easterly one is most probable in August. However, the low wind strength does not allow to be sure about the guessed configuration. Page E-12/32

E4.1.2. Visibility and weather phenomena Figure 6: Visibility and weather phenomena at LFPO During the most part of this period, the visibility was above 10 km. The visibility falls below 5 km during some rain periods (RA) and thunderstorms (TS). There were RVR items on 30 th July (at 8h), 8 th August (at 6h), 9 th August (from 5h30 to 6h30) and on 23 rd August (at 6h30) Page E-13/32

E4.1.3. Ceiling Figure 7: Ceiling at LFPO Page E-14/32

E4.1.4. QNH Figure 8: QNH at LFPO Page E-15/32

E4.2. PARIS CDG (LFPG) E4.2.1. Wind distribution Figure 9: Wind distribution at LFPG The runway orientations are 087 and 267. The QFU 09-27 and 08-26 correspond to the same magnetic orientation. Those naming are a way to avoid mistakes. Page E-16/32

E4.2.2. Visibility and weather phenomena Figure 10: Visibility and weather phenomena at LFPG There were RVR items on 18 th August (from 8h50 to 9h30), 23 rd August (from 5h30 to 6h33) and on 29 th August (from 5h to 8h) Page E-17/32

E4.2.3. Ceiling Figure 11: Ceiling at LFPG Page E-18/32

E4.2.4. QNH Figure 12: QNH at LFPG Page E-19/32

E4.3. LONDON HEATROW (EGLL) E4.3.1. Wind distribution Figure 13: Wind distribution at EGLL The runway orientations are 093 and 273 for the both runways. The others are not drawn. Page E-20/32

E4.3.2. Visibility and weather phenomena Figure 14: Visibility and weather phenomena at EGLL There was not any RVR items during this period. Page E-21/32

E4.3.3. Ceiling Figure 15: Ceiling at EGLL Page E-22/32

E4.3.4. QNH Figure 16: QNH at EGLL Page E-23/32

E4.4. LONDON GATWICK (EGKK) E4.4.1. Wind distribution Figure 17: Wind distribution at EGKK The runway orientations are 080 and 260. Page E-24/32

E4.4.2. Visibility and weather phenomena Figure 18: Visibility and weather phenomena at EGKK There were RVR items on t26 th July (from 17h50 to 18h20) and on 9 th August (from 6h50 to 7h20). Page E-25/32

E4.4.3. Ceiling Figure 19: Ceiling at EGKK Page E-26/32

E4.4.4. QNH Figure 20: QNH at EGKK Page E-27/32

E4.5. FRANKFURT (EDDF) E4.5.1. Wind distribution Figure 21: Wind distribution at EDDF The runway orientations are 069, 249 and 179. Page E-28/32

E4.5.2. Visibility and weather phenomena Figure 22: Visibility and weather phenomena at EDDF There was any RVR items during this period. Page E-29/32

E4.5.3. Ceiling Figure 23: Ceiling at EDDF Page E-30/32

E4.5.4. QNH Figure 24: QNH at EDDF Page E-31/32

E5. Acronyms ATIS BKN CENA CAVOK D-ATIS ETMA FALBALA FEW hpa OVC METAR NATS NOAA QFU QNH RVR SCT SOFREAVIA TMA UoG UTC VFR WMO WP Automatic Terminal Information Service Broken. Means: between ½ and ¾ of the sky covered with clouds Centre d Etudes de la Navigation Aérienne Cave and Visibility OK Digital Automatic Terminal Information Service Extended TMA First Assessment of the operational Limitations, Benefits & Applicability for a List of package I AS applications Means: less than ¼ of the sky covered with clouds hecto Pascal Overcast. Means: more than ¾ of the sky covered with clouds Meteorological Aerodrome Report National Air Traffic Services National Oceanic and Atmospheric Administration Magnetic Orientation of Runway Code Q, means: Atmospheric pressure reduced to sea level Runway Visual Range Scattered. Means: between ¼ and ½ of the sky covered with clouds Société Française d Etudes et Réalisations d Equipements Aéronautiques Terminal Manoeuvring Area University of Glasgow Co-ordinated Universal Time Visual Flight Rules World Meteorological Organization Work Package *** END OF DOCUMENT *** Page E-32/32