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Javier, You can find the definitions that GEMPAK uses to decode GRIB parameter numbers to GEMPAK variable names in $GEMTBL/grid. For the avn model, The parameter tables would be wmogrib2.tbl and ncepgrib2.tbl. For example, TMPK is temperature in Kelvin, no scaling (eg scales by 10**0): % grep TMPK $GEMTBL/grid/wmogrib2.tbl 011 Temperature K TMPK 0 -9999.00 The GRIB data provides parameter numbers, and the above tables will be used to identify the string used as the name in GEMPAK. The vertical coordinate names are defined in $GEMTBL/grid/vcrdgrib1.tbl. More information on GEMPAK parameters can be found in the User Guide in Chapter 3 (gparm and/or gfunc, as well as general lists in sfparm) and Appendix B for function computations. A parameter that has 2 levels is called a "layer" parameter. 2 levels will be used when the parameter is described in a layer, or between 2 levels, such as: Boundary layer parameters, where the levels are the top and bottom of the layer (eg PARM=TMPK, GLEVEL=180:0, GVCORD=PDLY is the temperature in the layer from 0 to 180 millibars above the ground. Stability parameters, such as the lifted index, lifted from 1000mb to 500mb; Helicity using the mean storm inflor from 0 to 3000m above the ground, etc. If you create thickness computations, such as GFUNC=ldf(hght), GLEVEL=500:1000, GVCORD=PRES, you will have a thickness (aka height difference (delta Z) or depth of a layer in the atmosphere) between 500mb and 1000mb for the height (HGHT) of pressure surfaces. Steve Chiswell Unidata User Support >From: "Francisco Javier Soley Alfaro." <address@hidden> >Organization: UCAR/Unidata >Keywords: 200108241829.f7OISd116278 >Dear Steve: > >Jimmy Mejia succeded in configuring Gempak and the ldm and we are getting >aviation data (*.avn) regularly. There are still problems with other type >of data. > >Several weeks ago I started playing again with gempak. I have decoded some >files using dcgrib and listed the information with gdinfo. I searched the >gempak documentation web pages looking for information on the gempak's own >data format. I could not find it. Where can I find the meaning of the >parameters: TMPK, UREL, VREL, etc. When do the grids have two levels? >I can guess to some of the meanings but I want to prepare a document in >Spanish that explains the data format for training purposes. >Thanks for your help. >Javier Soley > > > >