时间：2011-04-18 00:50来源：蓝天飞行翻译 作者：航空 点击：次
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4.Ceiling and Sky Cover. (a) Ceiling is announced as either “CEIL-ING” or “INDEFINITE CEILING.” With the exception of indefinite ceilings, all automated ceiling heights are measured. EXAMPLE. “Bremerton National Airport automated weather observa-tion, one four five six zulu. Ceiling two thousand overcast;” “Bremerton National Airport automated weather observa-tion, one four five six zulu. Indefinite ceiling two hundred, sky obscured.” (b) The word “Clear” is not used in AWOS due to limitations in the height ranges of the sensors. No clouds detected is announced as “NO CLOUDS BELOW XXX” or, in newer systems as “CLEAR BELOW XXX” (where XXX is the range limit of the sensor). EXAMPLE. “No clouds below one two thousand.” “Clear below one two thousand.” (c) A sensor for determining ceiling and sky cover is not included in some AWOS. In these systems, ceiling and sky cover are not announced. “SKY CONDITION MISSING” is announced only if the system is configured with a ceilometer and the ceiling and sky cover information is not available. 5. Remarks. If remarks are included in the observation, the word “REMARKS” is announced following the altimeter setting. 7.1.26 Meteorology (a)Automated “Remarks.” (1)Density Altitude. (2)Variable Visibility. (3)Variable Wind Direction. (b)Manual Input Remarks. Manual input remarks are prefaced with the phrase “OBSERVER WEATHER.” As a general rule the manual remarks are limited to: (1)Type and intensity of precipitation. (2)Thunderstorms and direction; and (3)Obstructions to vision when the visibili-ty is 3 miles or less. EXAMPLE. “Remarks ... density altitude, two thousand five hundred ... visibility variable between one and two ... wind direction variable between two four zero and three one zero ...observed weather ... thunderstorm moderate rain showers and fog ... thunderstorm overhead.” (c) If an automated parameter is “missing” and no manual input for that parameter is available, the parameter is announced as “MISSING.” For example, a report with the dew point “missing” and no manual input available, would be announced as follows: EXAMPLE. “Ceiling one thousand overcast ... visibility three ... precipitation ... temperature three zero, dew point missing ... wind calm ... altimeter three zero zero one.” (d) “REMARKS” are announced in the following order of priority: (1)Automated “REMARKS.” [a] Density Altitude. [b] Variable Visibility. [c] Variable Wind Direction. (2)Manual Input “REMARKS.” [a] Sky Condition. [b] Visibility. [c] Weather and Obstructions to Vision. [d] Temperature. [e] Dew Point. [f] Wind; and [g] Altimeter Setting. EXAMPLE. “Remarks ... density altitude, two thousand five hundred ... visibility variable between one and two ... wind direction variable between two four zero and three one zero ... observer ceiling estimated two thousand broken ... observer temperature two, dew point minus five.” d. Automated Surface Observing System (ASOS)/Automated Weather Sensor System (AWSS). The ASOS/AWSS is the primary surface weather observing system of the U.S. (See Key to Decode an ASOS/AWSS (METAR) Observation, FIG 7.1.8 and FIG 7.1.9.) The program to install and operate these systems throughout the U.S. is a joint effort of the NWS, the FAA and the Department of Defense. AWSS is a follow.on program that provides identical data as ASOS. ASOS/AWSS is designed to support aviation operations and weather forecast activities. The ASOS/AWSS will provide continuous minute-by-minute observations and perform the basic observing functions necessary to generate an aviation routine weather report (ME-TAR) and other aviation weather information. The information may be transmitted over a discrete VHF radio frequency or the voice portion of a local NAVAID. ASOS/AWSS transmissions on a discrete VHF radio frequency are engineered to be receivable to a maximum of 25 NM from the ASOS/AWSS site and a maximum altitude of 10,000 feet AGL. At many locations, ASOS/AWSS signals may be received on the surface of the airport, but local conditions may limit the maximum reception distance and/or altitude. While the automated system and the human may differ in their methods of data collection and interpretation, both produce an observation quite similar in form and content. For the “objective” elements such as pressure, ambient temperature, dew point temperature, wind, and precipitation accumula-tion, both the automated system and the observer use a fixed location and time-averaging technique. The quantitative differences between the observer and the automated observation of these elements are negligible. For the “subjective” elements, however, observers use a fixed time, spatial averaging technique to describe the visual elements (sky condition, visibility and present weather), while the automated systems use a fixed location, time averaging technique. Although this is a fundamental change, the manual and automated techniques yield remarkably similar results within the limits of their respective capabilities. Meteorology 7.1.27 1. System Description. (a)The ASOS/AWSS at each airport location consists of four main components: (1)Individual weather sensors. (2)Data collection and processing units. (3)Peripherals and displays. (b)The ASOS/AWSS sensors perform the basic function of data acquisition. They continuously sample and measure the ambient environment, derive raw sensor data and make them available to the collection and processing units. |
