時間：2011-04-18 00:50來源：藍天飛行翻譯 作者：航空 點擊：次
|
2. Every ASOS/AWSS will contain the following basic set of sensors: (a)Cloud height indicator (one or possibly three). (b)Visibility sensor (one or possibly three). (c)Precipitation identification sensor. (d)Freezing rain sensor (at select sites). (e)Pressure sensors (two sensors at small airports; three sensors at large airports). (f)Ambient temperature/Dew point tempera-ture sensor. (g)Anemometer (wind direction and speed sensor). (h) Rainfall accumulation sensor. 3. The ASOS/AWSS data outlets include: (a)Those necessary for on-site airport users. (b)National communications networks. (c)Computer-generated voice (available through FAA radio broadcast to pilots, and dial-in telephone line). NOTE. Wind direction broadcast over FAA radios is in reference to magnetic north. 4.An ASOS/AWOS/AWSS report without human intervention will contain only that weather data capable of being reported automatically. The modifier for this METAR report is “AUTO.” When an observer augments or backs.up an ASOS/AWOS/ AWSS site, the “AUTO” modifier disappears. 5.There are two types of automated stations, AO1 for automated weather reporting stations without a precipitation discriminator, and AO2 for automated stations with a precipitation discriminator. As appropriate, “AO1” and “AO2” shall appear in remarks. (A precipitation discriminator can deter-mine the difference between liquid and frozen/freezing precipitation). NOTE. To decode an ASOS/AWSS report, refer to FIG 7.1.8 and FIG 7.1.9. REFERENCE. A complete explanation of METAR terminology is located in AIM, Paragraph 7.1.30, Key to Aerodrome Forecast (TAF) and Aviation Routine Weather Report (METAR). 7.1.28 Meteorology FIG 7.1.8 Key to Decode an ASOS/AWSS (METAR) Observation (Front)Meteorology 7.1.29 FIG 7.1.9 Key to Decode an ASOS/AWSS (METAR) Observation (Back)7.1.30 Meteorology e.TBL 7.1.2 contains a comparison of weather observing programs and the elements reported. f.Service Standards. During 1995, a govern-ment/industry team worked to comprehensively reassess the requirements for surface observations at the nation’s airports. That work resulted in agreement on a set of service standards, and the FAA and NWS ASOS sites to which the standards would apply. The term “Service Standards” refers to the level of detail in weather observation. The service standards consist of four different levels of service (A, B, C, and D) as described below. Specific observational elements included in each service level are listed in TBL 7.1.3. 1.Service Level D defines the minimum acceptable level of service. It is a completely automated service in which the ASOS observation will constitute the entire observation, i.e., no additional weather information is added by a human observer. This service is referred to as a stand alone D site. 2.Service Level C is a service in which the human observer, usually an air traffic controller, augments or adds information to the automated observation. Service Level C also includes backup of ASOS elements in the event of an ASOS malfunction or an unrepresentative ASOS report. In backup, the human observer inserts the correct or missing value for the automated ASOS elements. This service is provided by air traffic controllers under the Limited Aviation Weather Reporting Station (LAWRS) process, FSS and NWS observers, and, at selected sites, Non.Federal Observation Program observers. Two categories of airports require detail beyond Service Level C in order to enhance air traffic control efficiency and increase system capacity. Services at these airports are typically provided by contract weather observers, NWS observers, and, at some locations, FSS observers. 3.Service Level B is a service in which weather observations consist of all elements provided under Service Level C, plus augmentation of additional data beyond the capability of the ASOS. This category of airports includes smaller hubs or special airports in other ways that have worse than average bad weather operations for thunderstorms and/or freezing/frozen precipitation, and/or that are remote airports. 4.Service Level A, the highest and most demanding category, includes all the data reported in Service Standard B, plus additional requirements as specified. Service Level A covers major aviation hubs and/or high volume traffic airports with average or worse weather. TBL 7.1.2 Weather Observing Programs Element Reported AWOS.A AWOS.1 AWOS.2 AWOS.3 ASOS Manual Altimeter X X X X X X Wind X X X X X Temperature/ Dew Point X X X X X Density Altitude X X X X Visibility X X X X Clouds/Ceiling X X X Precipitation X X Remarks X X Meteorology 7.1.31 TBL 7.1.3 7.1.13. Weather Radar Services a.The National Weather Service operates a network of radar sites for detecting coverage, intensity, and movement of precipitation. The network is supplemented by FAA and DOD radar sites in the western sections of the country. Local warning radar sites augment the network by operating on an as needed basis to support warning and forecast programs. b.Scheduled radar observations are taken hourly and transmitted in alpha-numeric format on weather telecommunications circuits for flight planning purposes. Under certain conditions, special radar reports are issued in addition to the hourly transmittals. Data contained in the reports are also collected by the National Center for Environmental Prediction and used to prepare national radar summary charts for dissemination on facsimile circuits. |
