Re: Nexrad L3 images

On Wed, 16 Apr 2003, David C Welsh wrote:

> Jeff,
>
> I need to get moving and get the Nexrad Level 3 data plotted by itself
> to get the flow of the images to the web pages going and not wait for
> the GEMPAK programmer.

OK..

>
> I have been reading the URL for setting up GDRADR to read the data files
> and put the data into GEMPAK grid files. I have looked at the 'NEXRAD
> composit tutorial'. I have differences with the LDM header I see and
> what the tutorial has. In the SDUS55 data type I have there seems to be
> 6 different types of data: NVL, NCR, N0R, N0S, N0V, and NTP. I want only
> N0R (for now).

Easy enough to cull the rest via regular expressions.

>
> In the datatype.tbl file for the NEXRIII entry, I do not see how to set
> up a template to get the N0R variable, since it is not part of the file
> name pattern I have. Any thoughts to get this to work with the FSL
> supplied product headers? Should I switch to another feed (Unidata?) and
> get the products that have the correct header as used in the tutorial to
> split out the product types to different files?

I do not know how FSL "delivers" the data...to avoid mismatching data and
header info with applications, it would be wise to get the data from us or
at least a Unidata participant.


>
> The tutorial says that the data are stored in files. 'When GDRADR is
> run,...'. How does it get run to do the latest data? Is it always
> running and 'sees' the new data file(s)? How does the plotter run to
> 'see' that new data has been gridded?

When using the LDM, the data is properly filed and decoded (if needed),
and GEMPAK will look in the dirs and plot what you desire. If automating
this process some scripts will need to be written (both GEMPAK, and
whatever plotting scheme you have chosen, to look in to the RADAR dir and
plot "latest" or something to that affect.


>
> 1. Should I continue with FSL supplied Nexrad Level 3 data, where the
> header supplies no info about which of 6 data types is in the file, or
> go with another feed that has the data type as part of the header? If
> so, where to get it?


Many folks at noaa are ingesting this data already, so if your LDM is up
and running please send fully qualified hostname, IP, and LDM version and
I will set you up with a feed.


>
> 2. How to get GDRADR running and have the datatype.tbl and nexrad.tbl
> configuration files set up correctly, for sites KBOU, KCYS, KGLD, and
> KPUB to be in their own image, to grid the current data? Does the grid
> file get overwritten or appended? If appended how to keep trimmed to a
> certain size?


You would probably want to initiate 4 cron jobs running GDRADR, and name
them site specific, and have the output go to name specific dirs. You can
over write or write new, I suspect you may wish to archive some of these
files for reference..


> 3. How to get the image plotter running to plot the current data?
>

I do not know what image plotter you are referencing...


For a sample of like work, I am generating Precipitable Water Vapor
products and overlaying IR sat composites via a GEMPAK script I wrote and
then placing it in cron..

http://www.unidata.ucar.edu/suominet/loop/loop2/suomi_ani_zoom.html

and

http://www.unidata.ucar.edu/suominet/

for other loops and the archive of old data..is this something akin to
what you desire..?


> Thanks for you help.
> --
> David C. Welsh
> US DoC, NOAA MC R/ET
> 325 Broadway
> Boulder, CO 80305
>
> O (303) 497-6510 F (303 497-6978
> http://www.etl.noaa.gov
>
>
>
Jeff Weber
Unidata Support