<div dir="ltr"><div>[1] Please: Always include the version of NCL you are using.</div><div><br></div><div>%> ncl -V</div><div><br></div><div>The most recent version is 6.6.2<br></div><div><br></div><div>[2] Before processing, you can examine a GRIB file's contents via:</div><div><br></div><div>%> <b>ncl_filedump</b> gfs.t00z.pgrb2.0p25.f001.grb | less</div><div><br></div><div>Do you see a variable named "TMP_P0_L102_GLL0" ?<br></div><div><br></div><div>[3] <br></div><div><br></div><div>grib_file = "gfs.t00z.pgrb2.0p25.f001" + ".grb"<br>
fin = addfile(grib_file, "r")<br>
varnames = getfilevarnames(fin)<br>
print(varnames)</div><div><br></div><div>The output you included shows only vertical dimension variables: lv_*</div><div>(0) lv_DBLL14_l1<br>
(1) lv_DBLL14_l0<br>
(2) lv_ISBL13<br> ......SNIP ......<br></div><div>(15) lv_HTGL2<br>
(16) lv_AMSL1<br>
(17) lv_ISBL0</div><div><br></div><div><br></div><div>Then, NCL tells you that the variable <span style="color:rgb(0,0,255)"><b>TMP_P0_L102_GLL0</b></span> <b>is not in the grib file </b></div><div><br></div><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Mar 8, 2021 at 1:35 PM dr.hieronymus--- via ncl-talk <<a href="mailto:ncl-talk@mailman.ucar.edu">ncl-talk@mailman.ucar.edu</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hi,<br>
<br>
Regarding the GFS files, I have written to NCEP. Thanks, that was a good <br>
idea.<br>
<br>
When using following code:<br>
<br>
;;; load ncl scripts/files<br>
load "/usr/lib/ncarg/nclscripts/csm/gsn_code.ncl"<br>
load "/usr/lib/ncarg/nclscripts/csm/gsn_csm.ncl"<br>
load "/usr/lib/ncarg/nclscripts/csm/contributed.ncl"<br>
<br>
begin<br>
<br>
;;; read data from grib file<br>
grib_file = "gfs.t00z.pgrb2.0p25.f001"<br>
fin = addfile(grib_file, "r")<br>
varnames = getfilevarnames(fin)<br>
<br>
print(varnames)<br>
printVarSummary(fin->TMP_P0_L102_GLL0)<br>
<br>
;;; get variables: level, variable, longitude, latitude<br>
;t2m = fin->TMP_P0_L102_GLL0(:,:)<br>
;lon = fin->lon<br>
;lat = fin->lat<br>
<br>
;;; convert to degrees<br>
;t2m = t2m-273.15<br>
<br>
end<br>
<br>
I get the following error message:<br>
<br>
warning:NclGRIB2: APCP_P8_L1 contains records that NCL cannot currently <br>
differentiate. One or more records will be ignored.<br>
warning:NclGRIB2: ACPCP_P8_L1 contains records that NCL cannot currently <br>
differentiate. One or more records will be ignored.<br>
fatal:GdsCEGrid: Invalid grid detected<br>
fatal:NclGRIB2: Couldn't handle dimension information returned by grid <br>
decoding<br>
fatal:NclGRIB2: Deleting reference to parameter because of decoding <br>
error<br>
fatal:GdsCEGrid: Invalid grid detected<br>
fatal:NclGRIB2: Couldn't handle dimension information returned by grid <br>
decoding<br>
fatal:NclGRIB2: Deleting reference to parameter because of decoding <br>
error<br>
...<br>
...<br>
...<br>
fatal:GdsCEGrid: Invalid grid detected<br>
fatal:NclGRIB2: Couldn't handle dimension information returned by grid <br>
decoding<br>
fatal:NclGRIB2: Deleting reference to parameter because of decoding <br>
error<br>
fatal:GdsCEGrid: Invalid grid detected<br>
fatal:NclGRIB2: Couldn't handle dimension information returned by grid <br>
decoding<br>
fatal:NclGRIB2: Deleting reference to parameter because of decoding <br>
error<br>
<br>
<br>
Variable: varnames<br>
Type: string<br>
Total Size: 144 bytes<br>
18 values<br>
Number of Dimensions: 1<br>
Dimensions and sizes: [18]<br>
Coordinates:<br>
(0) lv_DBLL14_l1<br>
(1) lv_DBLL14_l0<br>
(2) lv_ISBL13<br>
(3) lv_ISBL12<br>
(4) lv_SPDL11_l1<br>
(5) lv_SPDL11_l0<br>
(6) lv_ISBL10<br>
(7) lv_ISBL9<br>
(8) lv_HTGL8<br>
(9) lv_ISBL7<br>
(10) lv_SIGL6_l1<br>
(11) lv_SIGL6_l0<br>
(12) lv_ISBL5<br>
(13) lv_HTGL4<br>
(14) lv_PVL3<br>
(15) lv_HTGL2<br>
(16) lv_AMSL1<br>
(17) lv_ISBL0<br>
fatal:["Execute.c":6397]:variable (TMP_P0_L102_GLL0) is not in file <br>
(fin)<br>
fatal:["Execute.c":8640]:Execute: Error occurred at or near line 14 in <br>
file temperature_tmp.ncl<br>
<br>
Do I understand correctly that ncl has detected an invalid grid? Why?<br>
<br>
Thanks.<br>
<br>
<br>
<br>
Am 08.03.2021 16:44 schrieb Lyndz:<br>
> Hi,<br>
> <br>
> I'm not sure if this is an ncl question. You should have directed your<br>
> questions to the ncep help page (<br>
> <a href="https://www.ncep.noaa.gov/mail_dataquestions/" rel="noreferrer" target="_blank">https://www.ncep.noaa.gov/mail_dataquestions/</a>)<br>
> <br>
> *[1] *As far as I know, the .anl files are analyses files and were <br>
> already<br>
> assimilated with observations.<br>
> <br>
> *[2]* If you want to use the forecast, then use the files with the<br>
> following format (<br>
> <a href="https://nomads.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/gfs.20210308/12/" rel="noreferrer" target="_blank">https://nomads.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/gfs.20210308/12/</a>):<br>
> <br>
> gfs.t12z.pgrb2.0p25.f000<br>
> <<a href="https://nomads.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/gfs.20210308/12/gfs.t12z.pgrb2.0p25.f000" rel="noreferrer" target="_blank">https://nomads.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/gfs.20210308/12/gfs.t12z.pgrb2.0p25.f000</a>><br>
> <br>
> gfs.t12z.pgrb2.0p25.f001<br>
> <<a href="https://nomads.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/gfs.20210308/12/gfs.t12z.pgrb2.0p25.f001" rel="noreferrer" target="_blank">https://nomads.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/gfs.20210308/12/gfs.t12z.pgrb2.0p25.f001</a>><br>
> <br>
> etc..<br>
> <br>
> No need to download the other files!<br>
> <br>
> ncl_filedump gfs.t12z.pgrb2.0p25.f000.grb will give you the contents<br>
> of the file.<br>
> <br>
> If you want temperature, then look for the keyword "Temperature". This<br>
> will give u information about the variables such as below:<br>
> <br>
> float TMP_P0_L102_GLL0 ( lv_AMSL1, lat_0, lon_0 )<br>
> <br>
> center : US National Weather Service - NCEP (WMC)<br>
> <br>
> production_status : Operational products<br>
> <br>
> long_name : Temperature<br>
> <br>
> units : K<br>
> <br>
> _FillValue : 1e+20<br>
> <br>
> grid_type : Latitude/longitude<br>
> <br>
> parameter_discipline_and_category : Meteorological<br>
> products, Temperature<br>
> <br>
> parameter_template_discipline_category_number : ( 0, 0, <br>
> 0, 0 )<br>
> <br>
> level_type : Specific altitude above mean sea level (m)<br>
> <br>
> forecast_time : 72<br>
> <br>
> forecast_time_units : hours<br>
> <br>
> initial_time : 03/08/2021 (00:00)<br>
> <br>
> The variable name is the same for other GFS files, regardless of <br>
> resolution.<br>
> <br>
> *[3]* For documentation, check this:<br>
> <a href="https://www.emc.ncep.noaa.gov/emc/pages/numerical_forecast_systems/gfs/documentation.php" rel="noreferrer" target="_blank">https://www.emc.ncep.noaa.gov/emc/pages/numerical_forecast_systems/gfs/documentation.php</a><br>
> <br>
> *[4] *The files are archived in <a href="http://rda.ucar.edu" rel="noreferrer" target="_blank">rda.ucar.edu</a>. For the 25km GFS, for<br>
> example, see this link:<br>
> <br>
> <a href="https://rda.ucar.edu/datasets/ds084.1/#!docs" rel="noreferrer" target="_blank">https://rda.ucar.edu/datasets/ds084.1/#!docs</a><br>
> <br>
> <br>
> <br>
> Hope this helps.<br>
> <br>
> --Lyndz<br>
> <br>
> <br>
> <br>
> On Mon, Mar 8, 2021 at 8:05 PM dr.hieronymus--- via ncl-talk <<br>
> <a href="mailto:ncl-talk@mailman.ucar.edu" target="_blank">ncl-talk@mailman.ucar.edu</a>> wrote:<br>
> <br>
>> Hello,<br>
>> <br>
>> I am trying to dig through GFS files in GRIB2 format on NCEP's FTP<br>
>> server (<a href="https://www.nco.ncep.noaa.gov/pmb/products/gfs/" rel="noreferrer" target="_blank">https://www.nco.ncep.noaa.gov/pmb/products/gfs/</a>).<br>
>> <br>
>> Unfortunately, it is not very easy to get a proper overview. <br>
>> Therefore,<br>
>> my first question is whether there is documentation somewhere that<br>
>> describes the different formats/variants in detail.<br>
>> <br>
>> What one quickly notice and easy understand is that the GFS files are<br>
>> available in different resolutions (0.25°, 0.50°, 1.00°) and each GFS<br>
>> file is described by an index file. The GFS files with 0.25° <br>
>> resolution<br>
>> have an hourly granularity and the GFS files with 0.50° and 1.00°<br>
>> resolution have a three-hourly granularity.<br>
>> <br>
>> Then, there are the .anl and .f000 GFS files. I don't understand the<br>
>> difference between .anl and .f000. Is .f000 not a forecast? <br>
>> Furthermore,<br>
>> I noticed that the index files are different regarding .f000 and<br>
>> .f001-384 (0.25°) and .f000 and .f003-384 (0.50°, 1.00°).<br>
>> <br>
>> What also confuses me are the different GFS files, namely pgrb2, <br>
>> pgrb2b,<br>
>> pgrb2full and sfluxgrbfFFF. What are the differences exactly? <br>
>> According<br>
>> to the corresponding index files, the same physical variables are<br>
>> available in all different GFS files. Do these variables always have <br>
>> the<br>
>> same values in all GFS files? Doesn't it matter which file I use <br>
>> when<br>
>> I have decided on a resolution?<br>
>> <br>
>> I am actually only interested in the temperature 2 meters above the<br>
>> ground. Which file should I simply use?<br>
>> <br>
>> In addition, I also wanted to know if the initial values for each <br>
>> model<br>
>> run (00, 06, 12, 18) are published somewhere.<br>
>> <br>
>> Thank you in advance for your help.<br>
>> _______________________________________________<br>
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