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20000707: SAUS45 Reports



Peter,

While I can't do anything about the duplicate station naming, the
file naming templates in dchrly/dcmetr were designed to solve the problem 
with WMO header times versus obs times since the output gempak file name
is determined from the data in the ob. However, if you just use the LDM 
patterns for file names, then that is a problem. 

This also brings up the beware caveat for TESTM reports as well.

Chiz

On Fri, 7 Jul 2000, Peter Neilley wrote:

> Larry's message about the Wyoming DOT sites reminded me about something I've 
> been
> meaning to post here for awhile regarding METAR's in the SAUS45 and SXUS97 
> collectives.
> Care and caution needs to be used when dealing with these "extra" METARs.  I 
> think
> some of this info was posted in a thread awhile back, so sorry if this is not
> all new info.  Note that Larry referred to obs under the SDUS45 headings.... 
> many
> (if not all) of those obs are also carried under the SAUS45 heading, so the 
> info
> posted here also pertains to Cheyenne's DOT observations.
> 
> These bulletins seem to contain METAR's broadcast from local NWS offices, 
> mostly
> in the western US.  In many cases, the METARs contain reports that are not 
> broadcast
> in the normal (e.g. SAUS80) collectives.  Thus if one is looking for the 
> greatest
> possible observational coverage, grabing and using these "extra" METARs can 
> make a
> big difference in data sparce regions.  However, these reports have some 
> quirks about 
> them which can cause difficulties.
> 
> First of all, station IDs are not unique.  For example, the Rapid City office
> issues a METAR for station KSLK, but this ID is really for Saranac Lake NY.   
> For
> example, from 10Z today, KUNR (Rapid City NWS) issued:
> 
>   KSLK 070947Z AUTO 00000KT 17/11 RMK A01 Pk WND MM=
> 
> while the regular KSLK metar (in the SAUS70 collective) was
> 
>   KSLK 070951Z AUTO VRB03KT 5SM BR FEW005 OVC037 06/06 A3001 RMK AO2 SLK170 
> T006100056=
> 
> Thus if you combine these data into one database (e.g. GEMPAK file) and plot 
> the
> data, confusing results often occur if the ob from the Rapid City office gets 
> plotted
> in upstate NY.  Other known duplicate IDs are KMTR (from Cheyenne duplicate 
> with
> Monterey CA) and KPHP (from Goodland, duplicate with Philip SD).
> 
> Also, the times in the WMO headers for these bulletins often does not reflect 
> the observation
> hour.  The hour in the WMO header is not "rounded off" to the nearest hour 
> like most
> METAR collectives.    So if a ob is taken at 0957Z, it is sent with a WMO 
> header indicating
> 9Z, not 10Z like most of the normal (e.g. SAUS80) METARs.  Thus if you use 
> just the hour
> in the WMO header as the way in which data is sorted into times, you can 
> often get a
> mixed bag of obs from the same site.  If you then plot the obs from one hour, 
> the data
> may not all be syncronized.
> 
> For example, obs from Limon Colorado with 10Z headers today were broadcast 
> under each of the
> following headers:
> 
>   SAUS80 KWBC 071000
>      KLIC 070955Z AUTO 02004KT 10SM CLR 06/04 A3013 RMK A02 SLP138 T00560044 
> TSNO
> 
>   SAUS45 KPUB 071057
>      KLIC 071055Z AUTO 36003KT 10SM CLR 06/05 A3014 RMK A02 SLP140 T00610050 
> TSNO
> 
>   SAUS45 KBOU 071057 COR
>   MTRLIC
>      KLIC 071055Z AUTO 36003KT 10SM CLR 06/05 A3014 RMK A02 SLP140 T00610050 
> TSNO
> 
> Clearly the latter two obs were really 11Z obs (and indeed were contained in 
> the
> SAUS80 071100 collective).
> 
> But, if you stuffed all of the obs that had 10Z in the header into one 10Z 
> file, you would
> have obs for both (nominally) 10Z and 11Z obs if you had the SAUS45 
> collectives.
> 
> 
> Peter Neilley, NCAR/RAP
> address@hidden
> 303-497-8446
>