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<p>Thank you Denis,</p>
<p>just two questions about the equations that you show me: U10 = UL / [ 1 + (sqrt(CN10)/k)*log(ZL/10-PSI)] ; [1]</p>
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<p>1) Is UL the zonal component of the wind or the speed of the wind [v=sqrt((UL^2)+(VL^2))]?</p>
<p>2) <span id="result_box"><span>Where can I research about this formula that you gave me?</span></span></p>
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<p> Best regards.</p>
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<p>Leilane</p>
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<p>Em 12-06-2017 01:00, Dennis Shea escreveu:</p>
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<div>Sorry, I am not sure how to do this. <br /><br /></div>
You can readily get the height and wind components at the lowest model level. The method I suggested is my only guess. Maybe someone else has abetter idea.<br /><br /></div>
Good Luck</div>
<div class="gmail_extra"><br />
<div class="gmail_quote">On Tue, Jun 6, 2017 at 1:43 PM, <span><<a href="mailto:leilane.passos@inpe.br">leilane.passos@inpe.br</a>></span> wrote:<br />
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<p>Dear Denis,</p>
<p>Thank you for the answer.</p>
<p>I tried to make in another way. I interpolated from hybrid-sigma levels to pressure using the NCL script vinth2p_ecmwf.ncl, that is for CESM hybrid coordinates to pressure coordinates but uses an ECMWF formulation to extrapolate values below ground (<a href="https://bb.cgd.ucar.edu/converting-hybrid-levels-pressures">https://bb.cgd.ucar.edu/converting-hybrid-levels-pressures</a>). This interpolation was good, so I tried to do the interpolation from pressure to height, like your suggestions in this post: <a href="https://www.ncl.ucar.edu/Support/talk_archives/2004/0394.html">https://www.ncl.ucar.edu/Support/talk_archives/2004/0394.html</a><br /><br />And the interpolation was not good. Is there any NCL script to interpolate wind from pressure levels to 10m height? I need the wind in 10m just over the ocean.</p>
<p><span id="m_6849271967405665071result_box" class="m_6849271967405665071short_text"><span>My script is attached.</span></span></p>
<p><span class="m_6849271967405665071short_text"><span>Best regards.<br /></span></span></p>
<p><span class="m_6849271967405665071short_text"><span>Leilane</span></span></p>
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<p>Em 22-05-2017 16:49, Dennis Shea escreveu:</p>
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<div>The wrf_* functions were developed for the WRF model(s) with the WRF 'eta' vertical coordinate system.<br />[ <a href="https://www.researchgate.net/post/Does_WRF_simulation_use_sigma_or_eta_vertical_coordinate_system">https://www.researchgate.net/post/Does_WRF_simulation_use_sigma_or_eta_vertical_coordinate_system</a> ]<br /><br /></div>
<div>Hence, these functions are not appropriate for CAM data.</div>
<div>---</div>
<div>The calculation of CAM U10 is non-trivial. Many factors are involved: surface roughness, atmospheric stability, ...<br /><br /></div>
<div>Over the oceans, for neutral stability something like the following is used:</div>
<div><br /> U10 = UL / [ 1 + (sqrt(CN10)/k)*log(ZL/10-PSI)] ; [1] <br /><br /></div>
<div>The following variables are readily available at each grid point</div>
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<div>UL - zonal component of the wind at the Lowest model level<br />ZL - geopotential height at the Lowest model level</div>
<div>PSI - Sfc. geopotential<br /><br /></div>
<div> The CN10 must be derived:<br /><br /></div>
<div> CN10 - drag Coefficient at 10-m height and Neutral stability
<div style="font-size: 19.9253px; font-family: sans-serif;"> </div>
<div style="font-size: 19.9253px; font-family: sans-serif;"><span style="font-size: small;">where:</span></div>
<div style="font-family: serif;"><span style="font-size: small;"> CN10 = (C4/U10) + C5 + C6*U10 [2]<br /><br /></span></div>
<div style="font-family: serif;"><span style="font-size: small;">and, over the ocean,<br /></span></div>
<div style="font-size: 19.9253px; font-family: sans-serif;"><span style="font-size: small;"> C4=0.0027 m/s , C5=0.000142, C6=0.0000764 m/s<br /><br /></span></div>
<div style="font-size: 19.9253px; font-family: sans-serif;"><span style="font-size: small;">Note that U10 appears in both [1] and [2]. Hence the solution requires iteration.<br />----<br /></span></div>
<div style="font-size: 19.9253px; font-family: sans-serif;"><span style="font-size: small;">Over land, ????? <br />---<br /></span></div>
<div style="font-size: 19.9253px; font-family: sans-serif;"><span style="font-size: small;">If you need 'numbers' as a filler then maybe using a simple u10 = U*log(..) could be used. <br /><br /></span></div>
<div style="font-size: 19.9253px; font-family: sans-serif;"><span style="font-size: small;">Attached is a VERY SIMPLE function. The function requires 'surface roughness length' which can be a function of time (season). This information may be available online.<br /><br /></span></div>
<div style="font-size: 19.9253px; font-family: sans-serif;"><span style="font-size: small;">Also, as noted within the function, the approximation is most valid in the lowest 100m of the atmosphere.<br /></span></div>
<div style="font-size: 19.9253px; font-family: sans-serif;"><span style="font-size: small;"> </span></div>
<div style="font-size: 19.9253px; font-family: sans-serif;"><span style="font-size: small;">Good Luck<br /></span></div>
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<div class="gmail_quote">On Mon, May 15, 2017 at 1:09 PM, <span><<a href="mailto:leilane.passos@inpe.br">leilane.passos@inpe.br</a>></span> wrote:<br />
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<p>Hi,</p>
<p>I need to interpolate the wind results from CCSM4(CAM) in hybrid sigma level coordinate to height of 10 m. Then, I tried to use the function wrf_user_intrp3d with the u, v and the geopotential height (Z3), but the interpolated field has undefined values and I don't know the reason. I have the following questions:</p>
<p>1) I think that I should find the interpolated values in the entire domain. But why did I find undefined values in certain areas like Andes Chain?</p>
<p>2) If I use the command vinth2p to interpolate from hybrid to pressure coordinates, what is a similar function that I could use to convert from pressure to height of 10 m?</p>
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<p>; -------------- LOAD FUNCTIONS AND PROCEDURES ----------------<br /><br /> load "/usr/share/ncarg/nclscripts/csm/gsn_code.ncl"<br /> load "/usr/share/ncarg/nclscripts/csm/gsn_csm.ncl"<br /> load "/usr/share/ncarg/nclscripts/csm/contributed.ncl"<br /> load "/usr/share/ncarg/nclscripts/csm/shea_util.ncl"<br /> load "/usr/share/ncarg/nclscripts/wrf/WRFUserARW.ncl"<br /> load "/usr/share/ncarg/nclscripts/acentos.ncl"<br /><br /> ; -------------- BEGINING OF NCL SCRIPT ----------------<br /><br /> begin<br /><br /> outfile = "<a href="http://test_U10mV10m.1985.20thC.nc">test_U10mV10m.1985.20thC.nc</a>"<br /><br /> if (isfilepresent(outfile)) then<br /> system("rm -rf "+outfile) ;-- make sure that file does not exist<br /> end if<br /><br /> ;-- open data file<br /><br /> in_u = addfile("<a href="http://224331.U.1985.20thC.U.nc">224331.U.1985.20thC.U.nc</a>","r")<br /> in_v = addfile("<a href="http://224331.V.1985.20thC.V.nc">224331.V.1985.20thC.V.nc</a>","r")<br /> in_z = addfile("<a href="http://239928.Z3.1985.20thC.Z3.nc">239928.Z3.1985.20thC.Z3.nc</a>","r")<br /><br /> ;-- get variable t and its dimensions and dimension sizes<br /><br /> u = in_u->U ;(time, lev, lat, lon) ;-- get variable u<br /> v = in_v->V ;(time, lev, lat, lon) ;-- get variable v<br /> z = in_z->Z3 ;(time, lev, lat, lon) ;-- get variable u<br /><br /> time = in_u->time ;-- get dimension time<br /> lev = in_u->lev ;-- get dimension lev<br /> lat = in_u->lat ;-- get dimension lat<br /> lon = in_u->lon ;-- get dimension lon<br /><br /> ntim = dimsizes(time) ;-- get dimension sizes of time<br /> nlev = dimsizes(lev) ;-- get dimension sizes of lev<br /> nlat = dimsizes(lat) ;-- get dimension sizes of lat<br /> nlon = dimsizes(lon) ;-- get dimension sizes of lon<br /><br /> ;-- Interpolate u and v to 10m:<br /> ;u10m = u ;-- copy variable and its dimensions and attributes<br /> u10m = wrf_user_intrp3d(u,z,"h",10.0,0.,False) ;-- interpolate u<br /> u10m@units = "m/s" ;-- define new units<br /> ;v10m = v ;-- copy variable and its dimensions and attributes<br /> v10m = wrf_user_intrp3d(v,z,"h",10.0,0.,False) ;-- interpolate v<br /> v10m@units = "m/s" ;-- define new units<br /> ;print(u10m)<br /><br /> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;<br /> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;<br /> ;-- create new netCDF file<br /> fout = addfile(outfile,"c")<br /><br /> ;-- begin output file settings<br /> setfileoption(fout,"DefineMode",True) ;-- explicitly declare file definition mode<br /><br /> ;-- create global attributes of the file<br /> fAtt = True ;-- assign file attributes<br /> fAtt@title = "NCL Efficient Approach to netCDF Creation"<br /> fAtt@source_file = "CCSM4.nc"<br /> fAtt@Conventions = "CF"<br /> fAtt@creation_date = systemfunc ("date")<br /> fAtt@history = "NCL script: ex_netcdf_2.ncl"<br /> fAtt@comment = "Convert variable t: Kelvin to Celsius"<br /> fileattdef(fout,fAtt) ;-- copy file attributes<br /><br /> ;-- predefine the coordinate variables and their dimensionality<br /> dimNames = (/"time", "lat", "lon"/)<br /> dimSizes = (/ -1 , nlat, nlon /)<br /> dimUnlim = (/ True , False, False/)<br /> filedimdef(fout,dimNames,dimSizes,dimUnlim)<br /><br /> ;-- predefine the the dimensionality of the variables to be written out<br /> filevardef(fout, "time" ,typeof(time),getvardims(time))<br /> filevardef(fout, "lat" ,typeof(lat), getvardims(lat))<br /> filevardef(fout, "lon" ,typeof(lon), getvardims(lon))<br /> filevardef(fout, "u10m" ,typeof(u10m), getvardims(u10m))<br /> filevardef(fout, "v10m" ,typeof(v10m), getvardims(v10m))<br /><br /> ;-- copy attributes associated with each variable to the file<br /> filevarattdef(fout,"time" ,time) ;-- copy time attributes<br /> filevarattdef(fout,"lat" ,lat) ;-- copy lat attributes<br /> filevarattdef(fout,"lon" ,lon) ;-- copy lon attributes<br /> filevarattdef(fout,"u10m" ,u10m) ;-- copy u10m attributes<br /> filevarattdef(fout,"v10m" ,v10m) ;-- copy v10m attributes<br /><br /> ;-- explicitly exit file definition mode (not required)<br /> setfileoption(fout,"DefineMode",False)<br /><br /> ;-- output only the data values since the dimensionality and such have been predefined.<br /> ;-- The "(/", "/)" syntax tells NCL to only output the data values to the predefined<br /> ;-- locations on the file.<br /> fout->time = (/time/) ;-- write time to new netCDF file<br /><br /> fout->lat = (/lat/) ;-- write lat to new netCDF file<br /> fout->lon = (/lon/) ;-- write lon to new netCDF file<br /> fout->u10m = (/u10m/) ;-- write variable to new netCDF file<br /> fout->v10m = (/v10m/) ;-- write variable to new netCDF file<br /><br />end<br /><br /></p>
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<p>Best regards,</p>
<p>Leilane</p>
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