参考加国学习met3.17-3

1、Section 3.17METEOROLOGICAL SERVICES AVAILABLE TO PILOTSAviation Weather Information ServiceAWIS:Flight Service Stations (FSS) are equipped to provide weather information, both inflight and in the preflight stages.Preflight:the personnel provides a weather briefing to help you plan your flight, and i

2、t is given to you in plain language, they cover an area of 500nm from the FSS.Aviation Weather Information ServiceInflight Stage:they provide you with updated information.You can also inform FSS about weather you encounter.To contact FSS on 126.7 MHz or the frequency listed in the CFS, (specify whic

3、h frequency you are using), you can also contact FSS by phone using, 1-866- WXBRIEF.Aviation Weather Briefing ServiceAWBS:Available in some FSS, they are authorized to provide an interpretation, and adaptation of meteorological information information to fit the changing weather situation and specia

4、l needs of the user.Transcribed Weather Broadcast.TWB:recorded weather data is continuously broadcast on the primary low frequency navaid, (NDB).Includes, flight precautions, weather synopses, significant enroute weather, upper winds, pilot reports, radar reports, METAR and Specials, TAF (terminal f

5、orecast), NOTAM.They are updated as new reports are received.Pilots Automatic Telephone Weather Answering ServicePATWAS:It provides, METAR, TAF, aerodrome forecast, winds, temperature, icing, freezing level, turbulence, PIREPS, and daily sunrise and sunset times.Frequencies are located in the CFS.Au

6、tomatic Terminal Information Service.ATIS:Information such as wind, runway in use, NOTAM, ceiling, etc is continuously broadcast on the voice facility of the VOT, or on an assigned VHF/UHF frequency. Each recording is identified by a phonetic alphabet code letters.You should listen to the ATIS befor

7、e contacting tower on take-off or landing.Section 3.18AVATION WEATHER REPORTSAviation Routine Weather ReportsMETAR is a regular hourly report.SPECI is used when significant changes in weather conditions occur off the hour.Height: above ground level (AGL)Wind: VRB = less than 3 ktsCALM = 00 ktsAutoma

8、ted Weather Observation StationAWOS:Designed to electronically collect weather data and to disseminate partial or full surface weather observations.Identified by AUTO.AUTO2:give cloud height, sky cover, visibility, temperature, dew point, MSL pressure, wind, and precipitation, it does not issue spec

9、ials or altimeter settings.Should not be used by pilots who are self briefing, only in consultation with qualified AWB.Automated Weather Observation StationAUTO5:same as AUTO2 plus:contains data on cloud type up to 10000 ft AGL.Altimeter setting.Precipitation occurrence type and density.Human observ

10、ers can add remarks (CCA, CCB etc.)A voice generated message of the AWOS report has been developed via VHF radio or by phone.Pilot ReportsPIREPS:pilots are urged to volunteer reports of cloud tops, upper cloud layers, cruising level, wind velocity, and other meteorological information.They are issue

11、d as reported and at the time of report.Section 3.19AVAITION FORECASTSArea ForecastWeather conditions to be expected over a particular region.Issued 4 times per daily, 0000z, 0600z, 1200z, and 1800z.Valid for 12 hours.Describes conditions below FL240Height in ASL, unless notified.Outlook is valid fo

12、r 12 hours.Area ForecastIf wind is less than 20 Kts or visibility is greater than 6sm, not included, wind is reported in degrees true.Sky reported in octas, same as TAF and METAR.Terminal Area ForecastTAF:Aerodrome forecast states the expected weather conditions that will affect landing and take-off

13、 at the aerodrome.Conditions are given for an area within 5nm, of the aerodrome, winds are in degrees true.Issued for aerodromes for which METAR and SPECI are available.Valid 4 times per day at 06z, 12z, 18z, 24z.Terminal Area ForcastTAF cont;Cloud Height is AGL; and given in octas,Few 08 to 28.Sct

14、38 to 48.Bkn 58 to 88.Ovc 88.Upper Wind and Temperature ForecastFD:provides an estimate of upper wind conditions and temperature at selected levels, wind are in true to the nearest 10, wind speed in kts.Valid twice daily, 00z and 12z.Less than 5 kts: 9900.If wind is above 100 knots, coded 633950, 13

15、0139-50CMinus 50, Add 100Airmans Meteorological AdvisoryAIRMET: not a serious hazardous weather.Issued when required.Covers below 24000 ft.Significant In-Flight Weather Warning MessagesSIGMET:serious weather conditions reported as a warning to aircraft in flight.Section 3.20WEATHER MAPS and PROGNOST

16、IC CHARTSPrognostic Surface MapIssued 36 and 48 hrs before the valid time.Period of coverage 0z, and 12 z, (2 charts available for each time).Surface pressure patterns shown can be considered as representative of the atmosphere up to 3000 feet.Shows expected pressure pattern and frontal positions at the surface at a specific time in the future.Significant Weather Prognostic ChartsIssued 12 hrs before valid period.Periods of coverage ( 0z, 06z, 12z, 18z)Applicable Level: FL100-250 and FL250-600.Charts are for a specific flight level range. Indicates surface positions of Lows and Highs an