時間：2011-04-18 00:52來源：藍天飛行翻譯 作者：航空 點擊：次
|
a. Although the METAR code is adopted worldwide, each country is allowed to make modifications or exceptions to the code for use in their particular country, e.g., the U.S. will continue to use statute miles for visibility, feet for RVR values, knots for wind speed, and inches of mercury for altimetry. However, temperature and dew point will be reported in degrees Celsius. The U.S. will continue reporting prevailing visibility rather than lowest sector visibility. Most of the current U.S. observing procedures and policies will continue after the METAR conversion date, with the information disseminated in the METAR code and format. The elements in the body of a METAR report are separated with a space. The only exceptions are RVR, temperature and dew point, which are separated with a solidus (/). When an element does not occur, or cannot be observed, the preceding space and that element are omitted from that particular report. A METAR report contains the following sequence of elements in the following order: 1.Type of report. 2.ICAO Station Identifier. 3.Date and time of report. 4.Modifier (as required). 5.Wind. 6.Visibility. 7.Runway Visual Range (RVR). 8.Weather phenomena. 9.Sky conditions. 10.Temperature/dew point group. 11.Altimeter. 12.Remarks (RMK). AIM b. The following paragraphs describe the ele-ments in a METAR report. 1. Type of report. There are two types of report: (a)Aviation Routine Weather Report (METAR); and (b)Nonroutine (Special) Aviation Weather Report (SPECI). The type of report (METAR or SPECI) will always appear as the lead element of the report. 2.ICAO Station Identifier. The METAR code uses ICAO 4.letter station identifiers. In the contiguous 48 States, the 3.letter domestic station identifier is prefixed with a “K;” i.e., the domestic identifier for Seattle is SEA while the ICAO identifier is KSEA. Elsewhere, the first two letters of the ICAO identifier indicate what region of the world and country (or state) the station is in. For Alaska, all station identifiers start with “PA;” for Hawaii, all station identifiers start with “PH.” Canadian station identifiers start with “CU,” “CW,” “CY,” and “CZ.” Mexican station identifiers start with “MM.” The identifier for the western Caribbean is “M” followed by the individual country’s letter; i.e., Cuba is “MU;” Dominican Republic “MD;” the Bahamas “MY.” The identifier for the eastern Caribbean is “T” followed by the individual country’s letter; i.e., Puerto Rico is “TJ.” For a complete worldwide listing see ICAO Document 7910, Location Indicators. 3.Date and Time of Report. The date and time the observation is taken are transmitted as a six.digit date/time group appended with Z to denote Coordinated Universal Time (UTC). The first two digits are the date followed with two digits for hour and two digits for minutes. EXAMPLE. 172345Z (the 17th day of the month at 2345Z)4. Modifier (As Required). “AUTO” identi-fies a METAR/SPECI report as an automated weather report with no human intervention. If “AUTO” is shown in the body of the report, the type of sensor equipment used at the station will be encoded in the remarks section of the report. The absence of “AUTO” indicates that a report was made manually by an observer or that an automated report had human augmentation/backup. The modifier “COR” indi-cates a corrected report that is sent out to replace an earlier report with an error. Meteorology 7.1.61 NOTE. There are two types of automated stations, AO1 for automated weather reporting stations without a precipita-tion discriminator, and AO2 for automated stations with a precipitation discriminator. (A precipitation discriminator can determine the difference between liquid and frozen/freezing precipitation). This information appears in the remarks section of an automated report. 5. Wind. The wind is reported as a five digit group (six digits if speed is over 99 knots). The first three digits are the direction the wind is blowing from, in tens of degrees referenced to true north, or “VRB” if the direction is variable. The next two digits is the wind speed in knots, or if over 99 knots, the next three digits. If the wind is gusty, it is reported as a “G” after the speed followed by the highest gust reported. The abbreviation “KT” is appended to denote the use of knots for wind speed. EXAMPLE. 13008KT . wind from 130 degrees at 8 knots 08032G45KT . wind from 080 degrees at 32 knots with gusts to 45 knots VRB04KT . wind variable in direction at 4 knots 00000KT . wind calm 210103G130KT . wind from 210 degrees at 103 knots with gusts to 130 knots If the wind direction is variable by 60 degrees or more and the speed is greater than 6 knots, a variable group consisting of the extremes of the wind direction separated by a “v” will follow the prevailing wind group. 32012G22KT 280V350 (a)Peak Wind. Whenever the peak wind exceeds 25 knots “PK WND” will be included in Remarks, e.g., PK WND 28045/1955 “Peak wind two eight zero at four five occurred at one niner five five.” If the hour can be inferred from the report time, only the minutes will be appended, e.g., PK WND 34050/38 “Peak wind three four zero at five zero occurred at three eight past the hour.” (b)Wind shift. Whenever a wind shift occurs, “WSHFT” will be included in remarks followed by the time the wind shift began, e.g., WSHFT 30 FROPA “Wind shift at three zero due to frontal passage.” 6. Visibility. Prevailing visibility is reported in statute miles with “SM” appended to it. EXAMPLE. 7SM . seven statute miles 15SM . fifteen statute miles 1/2SM . one.half statute mile (a) |
