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[IDD #IWW-642097]: Canadian Radar Imagery

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  • Subject: [IDD #IWW-642097]: Canadian Radar Imagery
  • Date: Fri, 30 Jan 2009 07:39:43 -0700
Hi Russ,

re:
> Just wondering if you guys have access to digital data from the Canadian
> Weather Radar sites?

We are getting some Canadian radar data from PMEL (private company who is
evidently paying for the data) through a cooperative arrangement.  The data
is in ASCII text (!?) and represents precipitation values.  Chiz did some
work on converting the data back to reflectivities (using a Z-R relationship)
and incorporating them into our national reflectivity composite.  The result
was interesting, but evidently Chiz hit some snag that kept him from adding
them to the composite on a routine basis (his tests were for internal
consumption only).

Here is the response I sent to a user in Canada regarding the data in questin:

If you want to get the stations that Pelmorex is making available to Unidata,
please add the following request to your ~ldm/etc/ldmd.conf configuration
file and restart your LDM:

request EXP     "^([A-z][A-z][A-z])([0-3][PRS]).TXT.gz"   idd.unidata.ucar.edu

Here is an example GEMPAK pqact.conf action for uncompressing the products:

#
# Canadian radar data via Pelmorex
EXP     ^([A-z][A-z][A-z])([0-3][PRS]).TXT.gz
        PIPE    -close  decoders/dcgunzip -f data/gempak/nexrad/cradar/\1/C\2/C\
2_%Y%m%d_%H%M

Please note:

- these products are NOT in the same format as the NEXRAD Level III products;
  they are ASCII text

- they are not reflectivities; they are precipitation values.  Here are snippits
  of headers from the two different types of data I see from Pelmorex:

C1R:

MajorProductType RADAR
ValidTime 200811151320
DataType GeoReferencedField
FieldType GridIf you want to get the stations that Pelmorex is making available 
to Unidata,
please add the following request to your ~ldm/etc/ldmd.conf configuration
file and restart your LDM:

request EXP     "^([A-z][A-z][A-z])([0-3][PRS]).TXT.gz"   idd.unidata.ucar.edu

Here is an example GEMPAK pqact.conf action for uncompressing the products:

#
# Canadian radar data via Pelmorex
EXP     ^([A-z][A-z][A-z])([0-3][PRS]).TXT.gz
        PIPE    -close  decoders/dcgunzip -f data/gempak/nexrad/cradar/\1/C\2/C\
2_%Y%m%d_%H%M

Please note:

- these products are NOT in the same format as the NEXRAD Level III products;
  they are ASCII text

- they are not reflectivities; they are precipitation values.  Here are snippits
  of headers from the two different types of data I see from Pelmorex:

C1R:

MajorProductType RADAR
ValidTime 200811151320
DataType GeoReferencedField
FieldType Grid
Projection LatitudeLongitudeGrid
Scale 1
Width 480
Height 480
Interpolation NearestNeighbour
DataFormat Comma_Delim_Ascii,LatLonValue,Suppressed
SiteID XGO
SiteName HALIFAX
LatCentre 45.09889
LonCentre -63.70333
HornHeight 22 m
GroundHeight 210 m
Noise 50.8
Originator URP-1 Version 0.1
MinorProductType CAPPI
CAPPIHeight 1.5 km
Precipitation type: rain
Units: mm/hr


C1P:

MajorProductType RADAR
ValidTime 200811151310
DataType GeoReferencedField
FieldType Grid
Projection LatitudeLongitudeGrid
LatitudeIncrement 0.008994
LongitudeIncrement 0.012741
Scale 1
Width 480
Height 480
Interpolation NearestNeighbour
DataFormat Comma_Delim_Ascii,LatLonValue,Suppressed
SiteID XGO
SiteName HALIFAX
LatCentre 45.0989
LonCentre -63.7033
HornHeight 22
GroundHeight 210
Noise 50.95 

Projection LatitudeLongitudeGrid
Scale 1
Width 480
Height 480
Interpolation NearestNeighbour
DataFormat Comma_Delim_Ascii,LatLonValue,Suppressed
SiteID XGO
SiteName HALIFAX
LatCentre 45.09889
LonCentre -63.70333
HornHeight 22 m
GroundHeight 210 m
Noise 50.8
Originator URP-1 Version 0.1
MinorProductType CAPPI
CAPPIHeight 1.5 km
Precipitation type: rain
Units: mm/hr


C1P:

MajorProductType RADAR
ValidTime 200811151310
DataType GeoReferencedField
FieldType Grid
Projection LatitudeLongitudeGrid
LatitudeIncrement 0.008994
LongitudeIncrement 0.012741
Scale 1
Width 480
Height 480
Interpolation NearestNeighbour
DataFormat Comma_Delim_Ascii,LatLonValue,Suppressed
SiteID XGO
SiteName HALIFAX
LatCentre 45.0989
LonCentre -63.7033
HornHeight 22
GroundHeight 210
Noise 50.95 
Originator URP-1 Version 0.1
MinorProductType PRECIP

In order to be combined with the Nexrad Level III products, the rain rates
in the C1P products would need to be converted into reflectivities through
a Z-R relationship.  It would seem logical that this relationship would
change throughout the year.

Cheers,

Tom
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Ticket Details
===================
Ticket ID: IWW-642097
Department: Support McIDAS
Priority: Normal
Status: Closed