An ontology for use in converting METAR and TAF reports to DAML $Id: ont29,v 1.1.1.1 2002-12-19 19:24:30 bwm Exp $ Mapping from unit abbreviations to things used in this ontology. Eventually this could grow into a 'units' ontology and have mappings between various units. Unit Abbreviation Abbreviation for a unit of measure Abbreviation Name in the METAR ontology for a property referring to something measured in the units referenced to by the object with this property (is that clear?:) Property name C F mmHg inHg MPH Kts Canada's METAR format is similar to the US, but with a few subtle differences. Canada METAR report Superclass for everything reported in the Current Weather Condition group. Current weather conditions Fairly uniform precipitation composed exclusively of fine drops with diameters of less than 0.02 inch (0.5 mm) very close together. Drizzle appears to float while following air currents, although unlike fog droplets, it falls to the ground. Drizzle An ensemble of particles of dust or sand, sometimes accompanied by small liter, raised from the ground in the form of a whirling column of varying height with a small diameter and an approximately vertical vertical axis. Well-developed dust/sand whirl A severe weather condition characterized by strong winds and dust-filled air over an extensive area. Duststorm A visible aggregate of minute water particles (droplets) which are based at the Earth's surface and reduces horizontal visibility to less than 5/8 statute mile and, unlike drizzle, it does not fall to the ground. Fog A violent, rotating column of air which does not touch the surface. Funnel cloud gusting wind Precipitation in the form of small balls or other pieces of ice falling separately or frozen together in irregular lumps. Hail A suspension in the air of extremely small, dry particles invisible to the naked eye and sufficiently numerous to give the air an opalescent appearance. Haze Heavy Intensity variable direction wind (more than 6 knots) A fall of unbranched (snow crystals are branched) ice crystals in the form of needles, columns, or plates. Ice Crystals Precipitation of transparent or translucent pellets of ice, which are round or irregular, rarely conical, and which have a diameter of 0.2 inch (5 mm), or less. There are two main types: 1) Hard grains of ice consisting of frozen raindrops, or largely melted and refrozen snowflakes; 2) Pellets of snow encased in a thin layer of ice which have formed from the freezing, either of droplets intercepted by the pellets, or of water resulting from the partial melting of the pellets. Ice Pellets METAR report that adheres to the actual international METAR standard. International METAR report international-format surface visibility (d{4} in meters or CAVOK (ceiling and visibility OK Light Intensity variable direction wind (less than 6 knots) Medium Intensity Superclass for all METAR-format reports METAR report A visible aggregate of minute water particles suspended in the atmosphere that reduces visibility to less than 7 statute miles but greater than or equal to 5/8 statute mile. Mist Any phenomenon in the atmosphere, other than precipitation, that reduces the horizontal visibility. Obscuration Current weather phenomena that do not fit into either the obscuration or precipitation categories Other Weather Phenomena peak wind velocity Precipitation is any of the forms of water particles, whether liquid or solid, that fall from the atmosphere and reach the ground. Precipitation Precipitation, either in the form of drops larger than 0.02 inch (0.5 mm), or smaller drops which, in contrast to drizzle, are widely separated. Rain Runway visual range group - rarely used. Should probably break this into USA and international format RVR Runway visual range Sand particles raised by the wind to a height sufficient to reduce visibility. Sand Particles of sand carried aloft by a strong wind. The sand particles are mostly confined to the lowest ten feet, and rarely rise more than fifty feet above the ground. Sandstorm The descriptor shallow shall only be used to further describe fog that has little vertical extent (less than 6 feet). Shallow Precipitation characterized by the suddenness with which they start and stop, by the rapid changes of intensity, and usually by rapid changes in the appearance of the sky. Showers Precipitation of white, opaque grains of ice. The grains are round or sometimes conical. Diameters range from about 0.08 to 0.2 inch (2 to 5 mm). Small Hail and/or Snow Pellets A suspension in the air of small particles produced by combustion. A transition to haze may occur when smoke particles have traveled great distances (25 to 100 miles or more) and when the larger particles have settled out and the remaining particles have become widely scattered through the atmosphere. Smoke Precipitation of snow crystals, mostly branched in the form of six-pointed stars. Snow Precipitation of very small, white, and opaque grains of ice. Snow Grains SPECI special information METAR-format report SPECI report An ensemble of water droplets torn by the wind from the surface of an extensive body of water, generally from the crests of waves, and carried up a short distance into the air. Spray A strong wind characterized by a sudden onset in which the wind speed increases at least 16 knots and is sustained at 22 knots or more for at least one minute. Squall Surface visibility surface visibility TAF (Terminal Aerodrome Forecast) report. Unknown at this time whether this is a US-only or international standard, and if the conventions used are different. TAF report A local storm produced by a cumulonimbus cloud that is accompanied by lightning and/or thunder. Thunderstorm Timed weather event Timed and dated weather event Weather Event Time Range Weather event with possibly a beginning and possibly an ending has time Minutes past the hour, or hour and minutes, when some event occurred. has date Probably a day of the month. METAR is bizzare like that. has beginning time has ending time Funnel cloud / Tornadic Activity A violent, rotating column of air touching the ground. Tornado Unknown precipitation shall only be reported by automated stations to indicate precipitation of unknown type when the automated system cannot identify the precipitation with any greater precision. Unknown precipitation The US does everything differently, so it has its own wacky format for doing metar that's a bit different from everybody else's. US METAR report usa/canada-format surface visibility (garbage with fractions and statute miles) usa-format runway visual range (garbage with feet rather than meters) international-format runway visual range (uses meters) variable direction wind Unless otherwise directed elsewhere in this handbook, weather phenomena occurring beyond the point of observation (between 5 and 10 statute miles) shall be reported as (in the) vicinity. In the vicinity Superclass for everything dealing with visibility visibility Has temperature-valued or derived event Has pressure-valued or derived event Wind report A distance for visibility. Subclasses have some unit of distance attached. visibility distance Visibility in feet, for runway visual range reports Visibility in statue miles, for surface visibility reports Visibility in meters, for surface visibility reports Fine particles of rock powder that originate from a volcano and that may remain suspended in the atmosphere for long periods. Volcanic Ash A violent, rotating column of air that forms over a body of water, and touches the water surface. Waterspout Qualifiers/ descriptors of weather events Weather Descriptor Superclass for all weather events Weather event Weather Intensity Descriptor Weather Proximity Descriptor Current Weather Qualifier event is qualified by Superclass for all handled weather reports weather report Fine particles of earth or other matter raised or suspended in the air by the wind that may have occurred at or far away from the station which may restrict horizontal visibility. Widespread Dust Superclass for all events dealing with wind Wind event Wind direction Wind speed Speed of something, in knots Speed of something, in MPH Direction of wind, in degrees Wind direction (degrees) Direction of wind, in English Wind direction (degrees) wind shift event has report modifier Report modifier Automatic Corrected Every weather report must have a timestamp report was made at time Every weather report must have a timestamp day of the month report was made Every weather report must have a station ID has station ID Weather reports contain information about weather events. Wind report When dust, sand, snow, and/or spray is raised by the wind to a height of 6 feet or more, 'blowing' shall be used to further describe the weather phenomenon. Blowing When fog is occurring and the temperature is below 0oC, 'freezing' shall be used to further describe the phenomenon. When drizzle and/or rain freezes upon impact and forms a glaze on the ground or other exposed objects, 'freezing' shall be used to further describe the phenomenon. Freezing The descriptor partial and patches shall only be used to further describe fog that has little vertical extent (normally greater than or equal to 6 feet but less than 20 feet), and reduces horizontal visibility, but to a lesser extent vertically. The stars may often be seen by night and the sun by day. Partial Patches Sky condition is a description of the appearance of the sky. Sky condition may be evaluated either automatically by instrument or manually with or without instruments. Sky Condition VerticalVisibility Vertical visibility shall be coded in the format, VVhs hshs, where VV identifies an indefinite ceiling and hshshs is the vertical visibility into the indefinite ceiling. There shall be no space between the VV identifier and the vertical visibility. Clear Clear skies shall be coded in the format, SKC or CLR, where SKC is the abbreviation used by manual stations to indicate no layers are present and CLR is the abbreviation used by automated stations to indicate no layers are detected at or below 12,000 feet. Clear CLR is the abbreviation used by automated stations to indicate no layers are detected at or below 12,000 feet. Clear SKC is the abbreviation used by manual stations to indicate no layers are present Cloud Layer The sky cover for each layer reported shall be coded by using the appropriate reportable contraction from Table A-16. The abbreviations FEW, SCT, BKN, and OVC shall be followed without a space, by the height of the layer. Few Clouds Cloud layers covering 1/8 - 2/8 of the sky Scattered Clouds Cloud layers covering 3/8 - 4/8 of the sky. Coded with 'SCT' Broken Sky Cloud layers covering 5/8 - 7/8 of the sky. Coded with 'BKN' Overcast Cloud layers covering 8/8 of the sky. Coded with 'OVC' Cloud Type At manual stations, cumulonimbus (CB) or towering cumulus (TCU) shall be appended to the associated layer. Cumulonimbus Coded with 'CB' Towering Cumulus Coded with 'TCU' Superclass for events measuring a temperature, or quantities derived from a temperature. Measurement of a temperature value. Subproperties have units. degrees Celsius degrees Fahrenheit Superclass for temperature-related measurements derived from given information, e.g. heat index, wind chill, relative humidity Temperature In general, the degree of hotness or coldness of the ambient air as indicated on some definite scale as measured by any suitable instrument. Dew point The temperature to which a given parcel of air must be cooled at constant pressure and constant water-vapor content in order for saturation to occur. Relative Humidity Relative humidity is the current vapor pressure (saturation vapor pressure of the dewpoint) over the saturation vapor pressure of the current temperature) relative humidity (percentage) Percentage of the saturation vapor pressure that the current vapor pressure is. Heat Index Given the temperature and the dewpoint, the heat index can be derived. Wind Chill Given the temperature and the air speed velocity of an unladen swallow, the wind chill can be derived. Cumulative Event Superclass for all events or measurements that are an average, maximum, or minimum over a period of time more than that covered by one METAR report 3 Hour Cumulative Event An event that is an average, maximum, or minimum over a period of 3 hours 6 Hour Cumulative Event An event that is an average, maximum, or minimum over a period of 6 hours 24 Hour Cumulative Event An event that is an average, maximum, or minimum over a period of 24 hours Maximum Temperature 6-hour maximum temperature At designated stations, maximum and minimum temperatures that occurred in the previous 6 hours shall be determined to the nearest tenth of a degree Celsius for the 0000, 0600, 1200, and 1800 UTC observations 24-hour maximum temperature The maximum and minimum temperatures for the previous 24 hours shall be determined to the nearest tenth of a degree Celsius for the 0000 LST observation. Minimum Temperature 6-hour maximum temperature At designated stations, maximum and minimum temperatures that occurred in the previous 6 hours shall be determined to the nearest tenth of a degree Celsius for the 0000, 0600, 1200, and 1800 UTC observations 24-hour maximum temperature The maximum and minimum temperatures for the previous 24 hours shall be determined to the nearest tenth of a degree Celsius for the 0000 LST observation. Pressure Event Superclass for all events dealing with pressure Pressure Measurement Pressure measurement or reading - no implied units inHg Pressure measurement in inHg mmHg Pressure measurement in mmHg Altimeter Setting The pressure value to which an aircraft altimeter scale is set so that it will indicate the altitude above mean sea level of an aircraft on the ground at the location for which the value was determined. Sea-level pressure A pressure value obtained by the theoretical reduction of barometric pressure to sea level. Where the Earth's surface is above sea level, it is assumed that the atmosphere extends to sea level below the station and that the properties of that hypothetical atmosphere are related to conditions observed at the station. Pressure Change At designated stations, the pressure calculated for each report shall be examined to determine if a pressure change is occurring. If the pressure is rising or falling at a rate of at least 0.06 inch per hour and the pressure change totals 0.02 inch or more at the time of the observation, a pressure change remark shall be reported. 3-Hourly Pressure Tendency Increasing, then decreasing Applicable for 'Atmospheric pressure now higher than 3 hours ago' and 'Atmospheric pressure now same as 3 hours ago.' Increasing, then then steady, or increasing then increasing more slowly. Applicable for 'Atmospheric pressure now higher than 3 hours ago' Increasing steadily or unsteadily Applicable for 'Atmospheric pressure now higher than 3 hours ago' Decreasing or steady, then increasing; or increasing, then increasing more rapidly. Applicable for 'Atmospheric pressure now higher than 3 hours ago' Steady Applicable for 'Atmospheric pressure now same as 3 hours ago' Decreasing, then increasing Applicable for 'Atmospheric pressure now same as 3 hours ago' and 'Atmospheric pressure now lower than 3 hours ago.' Decreasing then steady; or decreasing then decreasing more slowly. Applicable for 'Atmospheric pressure now lower than 3 hours ago' Decreasing steadily or unsteadily. Applicable for 'Atmospheric pressure now lower than 3 hours ago' Steady or increasing, then decreasing; or decreasing then decreasing moe rapidly. Applicable for 'Atmospheric pressure now lower than 3 hours ago'