AWOS vs ASOS
06-26-2009 | 02:35 PM
#1
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From: CRJ
AWOS vs ASOS
Im lookinga t the commercial PTS and it says " Exibit knowledge of the elements of..." and then AWOS ASOS and ATIS is in there. My question is what exactly do we have to know about AWOS and ASOS, I cant really figure out the differences between the two except for the different types of AWOS's such as AWOS-A, AWOS-1 and the fact that some are owned by the FAA and others are locally owned. Am I missing something here or is it important I know all the extreme details of it to get thru the oral?
Thanks
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06-26-2009 | 03:01 PM
#2
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From: Dream within a dream
ASOS is more sophisticated than AWOS and is designed to provide the necessary information to generate actual weather forecasts. It can provide the continuous, minute-by-minute observations necessary for a METARs and TAFs. ALL ASOS systems can determine type and intensity of precip, thunderstorms, and obstructions to vis as well as peak wind, shifts, gusts, pressure changes, etc.
On the other hand, there are multiple types of AWOS with different capabilities, and they can be purchased by either the FAA or other groups and airport personnel:
AWOS-A: Only altimeter setting
AWOS-1: Altimeter, wind, temp, dew point, density alt.
AWOS-2: AWOS-1 plus visibility
AWOS-3: AWOS-2 plus cloud/ceiling data
AWOS-3 P: Adds a precip TYPE identifying sensor
AWOS-3 T: Adds a thunderstorm/lightning reporter
AWOS-3 P/T: Combines the above two
AWOS-4: Contains all the AWOS-3 systems plus precip occurrence, type, accumulation, freezing rain, thunderstorm, and runway surface condition sensors.
They normally don't go that in-depth on the oral, though
On the other hand, there are multiple types of AWOS with different capabilities, and they can be purchased by either the FAA or other groups and airport personnel:
AWOS-A: Only altimeter setting
AWOS-1: Altimeter, wind, temp, dew point, density alt.
AWOS-2: AWOS-1 plus visibility
AWOS-3: AWOS-2 plus cloud/ceiling data
AWOS-3 P: Adds a precip TYPE identifying sensor
AWOS-3 T: Adds a thunderstorm/lightning reporter
AWOS-3 P/T: Combines the above two
AWOS-4: Contains all the AWOS-3 systems plus precip occurrence, type, accumulation, freezing rain, thunderstorm, and runway surface condition sensors.
They normally don't go that in-depth on the oral, though
Last edited by Planespotta; 06-26-2009 at 06:03 PM.
06-27-2009 | 06:19 AM
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From: In the TRACON
I've worked with ASOS and AWOS-3, here are some observations . . .
With ASOS, the weather is transmitted automatically to the NWS and can be easily augmented by a weather observer (these are at a lot of FAA control towers). It is pretty good at figuring out cloud cover and precipitation. It knew when SPECIs had to be taken (and issued them automatically).
The AWOS system I worked with was not nearly as good. It did not transmit automatically to the NWS (but I think it can be set up to do that). It could not be augmented manually, so weather observations had to be taken manually and transmitted manually. It was poor at determining cloud heights and cover, and so-so at figuring out whether or not it was raining. It did not know when a SPECI needed to be issued.
Both had the ability to record a voice message (when the tower was closed, usually).
ASOS had the option of 1-minute weather updates or hourly updates when transmitting the weather (the automated voice on the phone or on the ASOS freq), so usually it is set for hourly when the tower is open, and 1 minute when the tower is closed (or when there is no tower). The AWOS system I used didn't have that option (as far as I knew).
At airports with control towers, the ATIS weather is usually pulled directly off the AWOS/ASOS screen while the controller is doing the recording. ASOS is tied into the NAS, so controllers can look up the METAR at nearby airports via the Flight Data computer if the airport is ASOS equipped. It's possible for AWOS-equipped airports, but someone has the manually enter the weather and transmit it to FSS or the NWS.
With ASOS, the weather is transmitted automatically to the NWS and can be easily augmented by a weather observer (these are at a lot of FAA control towers). It is pretty good at figuring out cloud cover and precipitation. It knew when SPECIs had to be taken (and issued them automatically).
The AWOS system I worked with was not nearly as good. It did not transmit automatically to the NWS (but I think it can be set up to do that). It could not be augmented manually, so weather observations had to be taken manually and transmitted manually. It was poor at determining cloud heights and cover, and so-so at figuring out whether or not it was raining. It did not know when a SPECI needed to be issued.
Both had the ability to record a voice message (when the tower was closed, usually).
ASOS had the option of 1-minute weather updates or hourly updates when transmitting the weather (the automated voice on the phone or on the ASOS freq), so usually it is set for hourly when the tower is open, and 1 minute when the tower is closed (or when there is no tower). The AWOS system I used didn't have that option (as far as I knew).
At airports with control towers, the ATIS weather is usually pulled directly off the AWOS/ASOS screen while the controller is doing the recording. ASOS is tied into the NAS, so controllers can look up the METAR at nearby airports via the Flight Data computer if the airport is ASOS equipped. It's possible for AWOS-equipped airports, but someone has the manually enter the weather and transmit it to FSS or the NWS.
