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19990610: ASOS
- Subject: 19990610: ASOS
- Date: Mon, 21 Jun 1999 10:51:29 -0600
Teresa,
The ASOS location heights are usually surveyed since most are deployed
at airports where the runway elevaltion is known.
Metar observations report mean sea level pressure (eg pressure reduced
to sea levl) and/or altimeter setting. Almost all stations report
altimeter setting since pilots need that measurement for landing.
From your previous list of stations:
Station Location On NOAAport
KSJT SAN ANGELO, TX Yes
KACV EUREKA, CA Yes
KRAL RIVERSIDE, CA Yes
KEKO ELKO, NV Yes
KBFI SEATTLE, WA Yes
KPRC PRESCOTT, AZ Yes
KDEN DENVER, CO Yes
KGTF GREAT FALLS, MT Yes
KGFX NO
KOLU COLUMBUS, NE Yes
KOKC OKLAHOMA CITY, OK Yes
KGRB GREEN BAY, WI Yes
KGWO GREENWOOD, MS Yes
XAND NO
KACY ATLANTIC CITY, NJ Yes
KDAY DAYTON, OH Yes
KBGR BANGOR, ME Yes
PABE BETHEL, AK Yes
PAOT KOTZEBUE, AK Yes
PASI SITKA, AK YES
PMNL NO
The 3 station you list that are not in our data stream are also not
in the NWS list of ASOS stations:
http://www.nws.noaa.gov/pub/modernize/asos.txt
Maybe typo in the station IDs- for example PHNL is Honolulu, KAND is
Anderson, SC.
For an example of Metar reports, here are those from Denver today from
12Z through 15Z, along with the decoded mean sea level pressure (PMSL)
Station pressure from altimeter setting (PALT), temperature (TMPC)
and dewpoint (DWPC)
KDEN 211153Z 20009KT 10SM FEW120 SCT250 14/07 A3003 RMK AO2 SLP097
T01440072 10167 20139 56008=
KDEN 211253Z 20010KT 10SM FEW100 SCT200 16/08 A3003 RMK AO2 SLP096
T01610078=
KDEN 211353Z 20009KT 10SM FEW100 SCT200 19/08 A3002 RMK AO2 SLP090
T01890083=
KDEN 211453Z 20010KT 10SM FEW140 SCT250 22/10 A3001 RMK AO2 SLP083
T02220100 58004=
STN YYMMDD/HHMM PMSL PALT TMPC DWPC
DEN 990621/1200 1009.70 832.43 14.39 7.22
DEN 990621/1300 1009.60 832.43 16.11 7.78
DEN 990621/1400 1009.00 832.16 18.89 8.28
DEN 990621/1500 1008.30 831.88 22.22 10.00
As you see in the 12Z report, the altimeter setting
appears as A3003 (or 30.03 inches), while the reduced SLP
is reported in the Remarks section as 1009.7mb.
Converting from Altimeter setting to station pressure requires use
of the station elevation.
Steve Chiswell
Unidata User Support
On Thu, 10 Jun 1999, Unidata Support wrote:
>
> ------- Forwarded Message
>
> >To: Unidata Support <address@hidden>
> >From: Teresa Van Hove <address@hidden>
> >Subject: Re: 19990421: 19990412: is ASOS data part of the unidata IDD flow?
> >Organization: GST
> >Keywords: 199906102122.PAA20245
>
> Hi Chiz,
>
> A couple questions on the ASOS data. Do you know how
> the ASOS height measurements are determined? I suppose
> they are sea-level, so I'll have to apply a geoid model
> to compare to the GPS antennas, but how accurate are
> the ASOS heights. Chris pointed out to me that we
> need to know the height differential between the ASOS
> and the GPS within a couple of meters. Second question:
> are the pressures converted to sea-level height, or does
> the metar data stream contain the station measurement as
> well. If only the sea-level height pressure is in the
> metar data stream is there one standard conversion formula
> to revert to station pressure or is the formula site
> dependant? A sample of the hourly data stream would
> still be helpfull too.
>
> Thanks,
> Teresa
>
> Unidata Support wrote:
> >
> > Teresa,
> >
> > We're out of our offices right now with the FUN thing- and
> > we've had our user committee meeting- so I haven't gotten back
> > to you sooner.
> >
> > The FAA sites etc are in the metar stream, and we have perl decoder
> > that can convert the METAR into NetCDF. Also, we have a grib decoder for
> > converting NCEP model data into NetCDF files for using to calculate
> > the retrieval coefficients you would need. The standard IDD data stream
> > has 3 hourly NCEP output in a model called RUC (rapid update cycle/FSL).
> > I also have separate model data feeds with hourly RUC output if that
> > is necessary- its a lot of data, and can really tie up a machine.
> >
> > I'll send you an output pf which stations in your list are in the
> > hourly data stream.
> >
> > Steve Chiswell
> > Unidata User SUpport
>
> >From address@hidden Thu Jun 10 15:34:24 1999
> Received: from cosmic.cosmic.ucar.EDU (address@hidden [128.117.29.214])
> by unidata.ucar.edu (8.8.8/8.8.8) with ESMTP id PAA20482
> for <address@hidden>; Thu, 10 Jun 1999 15:34:24 -0600 (MDT)
> Keywords: 199906102134.PAA20482
> Received: from ucar.edu by cosmic.cosmic.ucar.EDU (8.8.7/ NCAR Mail Server
> 04/10/90)
> id PAA26433; Thu, 10 Jun 1999 15:34:24 -0600
> Sender: address@hidden
> Message-ID: <address@hidden>
> Date: Thu, 10 Jun 1999 15:32:31 -0600
> From: Teresa Van Hove <address@hidden>
> Organization: GST
> X-Mailer: Mozilla 4.51 [en] (X11; I; Linux 2.2.5-15smp i686)
> X-Accept-Language: en
> MIME-Version: 1.0
> To: Unidata Support <address@hidden>
> Subject: [Fwd: 19990421: 19990412: is ASOS data part of the unidata IDD flow?]
> Content-Type: text/plain; charset=us-ascii
> Content-Transfer-Encoding: 7bit
>
> Sorry if this is a repeat, my machine crashed just as I
> sent it the first time.
>
> Teresa
>
>
>
> Teresa Van Hove wrote:
> >
> > Hi Chiz,
> >
> > A couple questions on the ASOS data. Do you know how
> > the ASOS height measurements are determined? I suppose
> > they are sea-level, so I'll have to apply a geoid model
> > to compare to the GPS antennas, but how accurate are
> > the ASOS heights. Chris pointed out to me that we
> > need to know the height differential between the ASOS
> > and the GPS within a couple of meters. Second question:
> > are the pressures converted to sea-level height, or does
> > the metar data stream contain the station measurement as
> > well. If only the sea-level height pressure is in the
> > metar data stream is there one standard conversion formula
> > to revert to station pressure or is the formula site
> > dependant? A sample of the hourly data stream would
> > still be helpfull too.
> >
> > Thanks,
> > Teresa
> >
> > Unidata Support wrote:
> > >
> > > Teresa,
> > >
> > > We're out of our offices right now with the FUN thing- and
> > > we've had our user committee meeting- so I haven't gotten back
> > > to you sooner.
> > >
> > > The FAA sites etc are in the metar stream, and we have perl decoder
> > > that can convert the METAR into NetCDF. Also, we have a grib decoder for
> > > converting NCEP model data into NetCDF files for using to calculate
> > > the retrieval coefficients you would need. The standard IDD data stream
> > > has 3 hourly NCEP output in a model called RUC (rapid update cycle/FSL).
> > > I also have separate model data feeds with hourly RUC output if that
> > > is necessary- its a lot of data, and can really tie up a machine.
> > >
> > > I'll send you an output pf which stations in your list are in the
> > > hourly data stream.
> > >
> > > Steve Chiswell
> > > Unidata User SUpport
>
>
> ------- End of Forwarded Message
>
>