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Hi Steve, Thanks for the reply. I guess the answer is that there is no way to get the shear for a specified layer (height AGL) depth directly using SNLIST. The NSHARP display gives the 0-2km, 0-6km etc shear vector, but I need to do it automatically. SNLIST looks like it will give me an interpolated value for parameters like PRES, SPED, DRCT at a specified height. I could get the wind vectors at levels like 1km, 3km AGL and then do a vector difference between the surface and that level. Do you think that is my only option with SNLIST? thanks again, Matt Unidata Support wrote: > Matt, > > The station elevation can be obtained with the STNDEX parameter "SELV". > SELV is also output in the station information at the top of the output > along with station lat/lon and time. > > The surface should be the first level of the sounding output. The hght of that > levels will be the height of the station. > > The SHRM parameter will be the value in each layer of the sounding. That is, > the value is calculated using each successive level of the sounding. To > only get the the 1091km level, you would use: levels = 1091. However, the > value of SHRM that would be output would be the shear in the layer in which > the 1091 meter level occurs. It would not be the mean from surface to that > layer. > There is no function that would give you the mean of shear in a specified > layer. > The STNDEX functions allow the user to specify the layer depth and surface > using > the "!" characters. However, SHRM is a level parameter, not a STNDEX function. > > Steve Chiswell > Unidata User Support > > >From: "Matthew Menne" <address@hidden> > >Organization: National Climatic Data Center, NOAA > >Keywords: 200112181525.fBIFPsN07532 > > >This is a multi-part message in MIME format. > >--------------615C49252F8A820704026C58 > >Content-Type: text/plain; charset=us-ascii > >Content-Transfer-Encoding: 7bit > > > >I would like to calculate the wind shear magnitude between the surface > >and a specified height above ground level (AGL) and I'm not sure that I > >am doing it correctly (using SNLIST). > > > >Is there a way to specify height AGL directly or do I need to know the > >station's elevation and then add some height value to it? > > > >I tried the latter in an attempt to get the mean wind shear for the > >layer 0-1km AGL for JAN (wmo=72235) whose elevation is 91 meters > > > > > > snlist << EOF > > snfile = ${file}_upa.gem > > dattim = all > > output = f/shear_${STN}_19${YEAR}${mon_str} > > snparm = SHRM > > stndex = > > levels = 91-1091-1000 > > vcoord = hght > > mrgdat = y > > area = @${STN} > > r > > > > > >When I run a script like the one above I get two numbers: one for 91 m > >and another for 1091 m, but I only expected one number (the mean between > >91 and 1091 m). Could you help me interpret these numbers or suggest > >how to extract the shear values that I'm looking for? Also, is there > >any way to obtain and use the station elevation value automatically in a > >script somehow? > > > >Thanks for the help. > > > > > >--------------615C49252F8A820704026C58 > >Content-Type: text/x-vcard; charset=us-ascii; > > name="Matthew.Menne.vcf" > >Content-Transfer-Encoding: 7bit > >Content-Description: Card for Matthew.Menne > >Content-Disposition: attachment; > > filename="Matthew.Menne.vcf" > > > >begin:vcard > >n:Menne;Matthew > >tel;work:(828) 271-4449 > >x-mozilla-html:FALSE > >org:National Climatic Data Center/NOAA;Scientific Services Division > >version:2.1 > >email;internet:address@hidden > >adr;quoted-printable:;;151 Patton Avenue=0D=0A;Asheville;NC;28801;USA > >fn:Matthew Menne > >end:vcard > > > >--------------615C49252F8A820704026C58-- > > > > **************************************************************************** < > Unidata User Support UCAR Unidata Program < > (303)497-8644 P.O. Box 3000 < > address@hidden Boulder, CO 80307 < > ---------------------------------------------------------------------------- < > Unidata WWW Service http://www.unidata.ucar.edu/ < > **************************************************************************** <
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