Table Of Content

iU 5~ 3 Automated Surface Observing System (Asusj New Automated Surface Observing ASOS detects significant changes, Systems (ASOS) are currently being disseminating hourly and special installed atover 850 locationsthroughout observations via the NWS and FAA the U.S. TheASOSprogram isajointeffort communications networks. Additionally, of the National Weather Service (NWS), ASOS will routinely and automatically the FederalAviationAdministration (FAA), provide computer-generated voice and the Department of Defense (DOD). observationsdirectlytoaircraftinthevicinity When installation iscompleted inthe mid- ofairports, using FAAground-to-airradio. 1990s, theASOSsystemswill serveasthe These messages will also be available via nation's primary surface weather a telephone dial-in port at the ASOS. observing network. ASOS is designed to support weather forecast activities and aviationoperationsand, atthesametime, support the needs ofthe meteorological, hydrological, and climatological research communities. With the largest and most modern complement of weather sensors, ASOS will significantly expand the information available to forecasters and the aviation community. The ASOS network more will thandoublethenumberoffull-timesurface weatherobservinglocations. ASOSworks non-stop, updating observations every minute, 24 hours a day, every day of the year. Getting more information on the atmosphere, more frequently and from more locations, is the key to improving forecasts and warnings. Thus, ASOS NWS information will help the to increase theaccuracya—ndtimelinessofitsforecasts and warnings the overriding goal of the NWS modernization. The primary concern of the aviation community is safety, and weather A conditions often threaten that safety. ASOS basic strength of is that critical aviation weather parameters are measured where they are needed most: airport runway touchdown zone(s). The ASOS sensors include: ftEfcffttSYLIMm TA7E u ^versSty • Cloud Height • Visibility • Precipitation Identification • Freezing Rain • Pressure • Temperature/Dew Point JUL xQ ]ggo Wind Direction and Speed • Precipitation Accumulation DOCUMENT^ A0Q0DElE3MEflt> ASOS Features Observes, formats, archives and transmits observations automatically. When preselected Pressure: sea-level pressure, altimeter setting weather element thresholds are exceeded (e.g., the visibility decreases to less than 3 Ambient temperature, dew point temperature miles), a "special" report is transmitted. Wind: direction, speed and character (gusts, Reports basic weather elements: squalls) • Sky condition: cloud height and amount (clear, Precipitation accumulation scattered, broken, overcast) up to 12,000 feet Selected significant remarks including - variable cloud height, variable • Visibility (to at least 10 statute miles) ^ visibility, precipitation beginning/ • Basic present weather information: type and ending times, rapid pressure £• intensity for rain, snow, and freezing rain changes, pressure change ten- dency, wind shift, peak wind. • Obstructions to vision: fog, haze