NOTICE: This version of the NSF Unidata web site (archive.unidata.ucar.edu) is no longer being updated.
Current content can be found at unidata.ucar.edu.
To learn about what's going on, see About the Archive Site.
NOTICE: This version of the NSF Unidata web site (archive.unidata.ucar.edu) is no longer being updated.
Current content can be found at unidata.ucar.edu.
To learn about what's going on, see About the Archive Site.
Two clarifications 1. In the ftp link be sure you replace YYYYMMDD with the present year month day and ditto for CC with the cycle 2. I had a type on the copygb link - it should end with copygb.fd (not copybg.fd, sorry about that). From: Peter C Manousos/FirstEnergy To: gembud@xxxxxxxxxxxxxxxx Date: 10/18/2013 11:38 AM Subject: Re: [gembud] Degribbing Ukmet Grib1 from tgftp site Greetings. After much trial and error over the past few weeks and with guidance from NCEP (thanks to Brill, Klein, Ebisuzaki, and Iredell) we were able to develop a method using available tools to pull in the UKMET grib files, process them with copygb and wgrib, and then pump them through nagrib to get gempak grids. Recall that these files can not directly be nagribbed properly (from ftp://tgftp.nws.noaa.gov/SL.us008001/ST.opnl/MT.bmoav_CY.CC/RD.YYYYMMDD/PT.grid_DF.bb ). This is because of the following: These are thinned gribs (number of x points decreases as you head toward the poles) For a given fhr and field and level (like f12 height 500mb) you get EIGHT tiles with the SAME name in the SAME grib file. This implies one must take extra steps for a given fhr, field, and level to figure out how to recognize the differences between each tile, stitch them together, and create a contiguous "non thinned" grib field so NAGRIB can chew on it. Fun. So the approach we took to fully automate this process was the following: Loop through each fhr -- pull data from ftp site Use wgrib (not wgrib2) to detect what parameters and levels exist in the pulled grib file For each parameter/field at the given fhr use wgrib to recognize which records contain the tile over the globe you wish to stitch Use copygb to convert and merge (stitch) the thinned grib tiles into an NCEP grid of your choice nagrib into a gempak grid Soak, rinse and repeat copygb comes with WRF EMS but if you don't have it copygb is available at http://www.nco.ncep.noaa.gov/pmb/codes/nwprod/util/sorc/copybg.fd/ (be sure to read the documentation) We recommend you manually try out the process and test it gives you what you think it should before writing a script to automate. But the pieces are here and it does work. Pete From: pmanousos@xxxxxxxxxxxxxxxxxxx To: gembud@xxxxxxxxxxxxxxxx Date: 09/25/2013 01:34 PM Subject: [gembud] Degribbing Ukmet Grib1 from tgftp site Sent by: gembud-bounces@xxxxxxxxxxxxxxxx Greetings. We are receiving an NOBNDS - No grid points in graphics area [DG -40] Subset grid bounds cannot be computed message from gdplot3 on nagribbed ukmet files retrieved from the tgftp server. We suspect it has something to do with the grib files and know just enough about grib to get by, but not enough to address this issue properly. It seems like some key piece of info in the grib message is missing causing GEMPAK to fail. We have done searching on google, gembud, and experimented unsuccessfully with cnvgrb, dcgrib and ultimately get the same null result. If anyone is successfully converting ukmet grib files from the tgftp server into GEMPAK grids (that are plottable in gdplot3) we would appreciate any advice. For reference here is how we get from the grib file to grid file: Pull ftp://tgftp.nws.noaa.gov/SL.us008001/ST.opnl/MT.bmoav_CY.CC/RD.YYYYMMDD/PT.grid_DF.bb/fh.0012_t1.hight (where CC is the current cycle and YYYYMMDD the present date) Degrib using nagrib (output file is test.grd -- using GDS in CPYFIL and maxgrids=4000) gdinfo on test.grd shows what you would expect (proper date/times, levels, gvcords, gridnames) Plotting in gdplot3 yields the NOBNDS error Pete ----------------------------------------- The information contained in this message is intended only for the personal and confidential use of the recipient(s) named above. If the reader of this message is not the intended recipient or an agent responsible for delivering it to the intended recipient, you are hereby notified that you have received this document in error and that any review, dissemination, distribution, or copying of this message is strictly prohibited. If you have received this communication in error, please notify us immediately, and delete the original message._______________________________________________ gembud mailing list gembud@xxxxxxxxxxxxxxxx For list information or to unsubscribe, visit: http://www.unidata.ucar.edu/mailing_lists/ ----------------------------------------- The information contained in this message is intended only for the personal and confidential use of the recipient(s) named above. If the reader of this message is not the intended recipient or an agent responsible for delivering it to the intended recipient, you are hereby notified that you have received this document in error and that any review, dissemination, distribution, or copying of this message is strictly prohibited. If you have received this communication in error, please notify us immediately, and delete the original message.
gembud archives: