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20040318: satz/ch1 vs satz/ch2 LDM feed

David,

Typically, you should expect supernational to send the products
for ch1 at 15 and 45 minutes after the hour, and ch2 at 0 and 30
minutes, where ch1 is GOES-12 and ch2 is GOES-10
(for weather offices that receive only the west or east
satellite feeds). You will see half the image update each 15 minutes.

The ch2 with ID GOES-12 seems to be an NWS artifact
of producing both 4km and 8km WV products for AWIPS
since the switch from GOES-11 (recall that an NWS office would only
see ch1 or ch2, but not both). The products have different checksums,
so the LDM will treat them as different regardless of the "TIGN05"
wmo header being a duplicate.

To prevent conflict, you might want to make the pattern
expect (ch1/GOES-12|ch2/GOES-10).

Steve Chiswell
Unidata User Support


.




>From: David Ovens <address@hidden>
>Organization: UCAR/Unidata
>Keywords: 200403182035.i2IKZurV015447

>Hello Unidata support,
>
>We've been having trouble with our LDM overwriting and corrupting some
>of our GINI imagery.  Turns out we are getting duplicate (?) files at
>nearly the same time on the satz/ch1 and satz/ch2 feeds.
>
>Here's an example from my diagnostic output from an ldmd.log:
>
>duplication: GOES-12/WV/20040318 1015/SUPER-NATIONAL/8km on ch2 at 
>20040318104014.158
>        and: GOES-12/WV/20040318 1015/SUPER-NATIONAL/8km on ch1 at 
>20040318104022.994
>         in: ldmd.log.9:Mar 18 10:40:24 glacier pqact[143742]:   416318 
>20040318104022.994  NIMAGE 18777  satz/ch1/GOES-12/WV/20040318 
>1015/SUPER-NATIONAL/8km/ TIGN05 KNES 181015
>
>Previously, we have ignored the ch1|ch2 line and filed these all in
>
>  gempak/nport/IMAGE/SUPER-NATIONAL/8km/WV
>
>using this pqact.conf entry
>
>  NIMAGE       ^satz/ch[0-9]/.*/(.*)/([12][0-9])([0-9][0-9])([01][0-9])([0-3][
> 0-9]) 
>([0-2][0-9])([0-5][0-9])/(.*)/(.*km)/
>       PIPE    -close
>       /home/disk/ldm/local/bin/gini/zlib2gif.pl /home/glacier/ldm/nport/IMAGE
> /\8/\9/\1/\1_\2\3\4\5_\6\7
>
>What is the difference between the ch1 and ch2 feeds?  Should we
>ignore one of them, or does one serve as a backup if the other is down?
>
>Thanks for any info.
>
>David
>-- 
>David Ovens             e-mail: address@hidden
>Research Meteorologist    phone: (206) 685-8108
>Dept of Atm. Sciences      plan: Real-time MM5 forecasting for the
>Box 351640                        Pacific Northwest
>University of Washington          http://www.atmos.washington.edu/mm5rt
>Seattle, WA  98195               Weather Graphics and Loops
>                                  http://www.atmos.washington.edu/~ovens/loops
>
>
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