**To**:**Joe McLean <joe.mclean@xxxxxxxx>****Subject**:**Re: geostrophic current****From**:**Namba Takaya <takayanamba7@xxxxxxxxxxx>**- Date: Wed, 8 Dec 2004 03:59:21 +0900 (JST)
- Cc: ferret_users@xxxxxxxx
- In-reply-to: <41B5E9A0.6050106@noaa.gov>
- Sender: owner-ferret_users@xxxxxxxxxxxxx

Joe and Jason Thank you very much for your mail and consideration. I could convert World Ocean Atlas 1/4 to netcdf using Jason Kurian's script. Say thanks to you again. Best Regards, Takaya Namba --- Joe McLean <joe.mclean@noaa.gov> からのメッセージ： > Hi Takaya-san, > > Were you able to use jason Kurian's script to read > and write the 1/4 > degree resolution data to netCDF files? Its good if > that worked out. > Would it be possible for me to transfer them to our > machine for public > access via the NVODS LAS > (http://www.ferret.noaa.gov/nvods) and OPeNDAP > (http://www.ferret.noaa.gov/cgi-bin/dods/nph-dods/data/PMEL/) > data > servers? I think there are others in the Ferret > community who would be > interested in this data. > Thank you, > Joe > > Namba Takaya wrote: > > >Dear Sir > > > >I have tried to calculate the geostrophic current > with the > >script below by Dr. David Oxilia > >submitted to the mailing list on 15th Jan 1999. > >In addition, I have the World Ocean Atlas 1/4 (24 > standard > >levels) supported by Dr. Jaison Kurian. > >However, I could not succeed in this calculation as > some > >axis errors come. Especially I do not have > confidence of > >two lines > >set reg/i=660:720/j=120:200/k=1:24 > >and > >let rho = rho_un(ss[G=ggrid],tt[G=ggrid],z) > >Could you give me some suggestions? > > > >============= geostrophic current script ========== > >! Set your data file (I assume you have a netCDF > file of > >model output) > >!!!use SaltTemp > >use woa01_salt.nc > >use woa01_temp.nc > >let ss=salt[d=woa01_salt.nc,l=1] !!!WOA 1/4 > salinity > >let tt=temp[d=woa01_temp.nc,l=1] !!!WOA 1/4 > temperature > >! Set parameters > >let g = 9.81 > >let pi = 3.14159 > >let omega = 7.292e-5 > >let f = 2*omega*sin(y*pi/180) > >define axis/x=160e:180e:0.25/unit=degree xxaxis > >define axis/y=60s:40s:0.25/unit=degree yyaxis > >define axis/z zaxis = {0, 10, 20, 30, 50, 75, 100, > 125, > >150,\ > >200, 250, 300, 400, 500, 600, 700, 800, 900, \ > >1000, 1100, 1200, 1300, 1400, 1500} > >define grid/x=xxaxis/y=yyaxis/z=zaxis ggrid > >! Set region to all space (use actual values for > ni, nj > >and nk) > >!set reg/i=1:ni/j=1:nj/k=1:nk > >set reg/i=660:720/j=120:200/k=1:24 > >!!!set reg/x=165e:180e/y=60s:40s/z=0:1500 > > > > > >! Compute density > >! I'll assume you have two variables S and T in > your data > >file and that > >! your vertical levels are in dbars (meters would > be > >pretty close) > >let rho = rho_un(ss[G=ggrid],tt[G=ggrid],z) > > > >! Compute vertical shears > >let gamma = g/(rho*f) > >let u_z = gamma*rho[y=@DDC] > >let v_z = gamma*rho[x=@DDC]*(-1) > > > >! Compute geostrophic field > >! To compute absolute velocity you either have to > know > >some reference > >! velocity or assume a level of no motion (as is > >traditionally done) > >! The level of no motion argument is what is used > when > >calculating > >! the surface geostrophic field from "dynamic > topography". > >You can > >! assume that the flow is zero at the bottom for > example > >and then > >! integrate vertically to the level at which you > want the > >flow field. > > > >! The flow field at the surface > >let u = u_z[k=@DIN] > >let v = v_z[k=@DIN] > >! The flow field at the base of a 100 m mixed layer > >assuming the > >! depth of no motion is at 5000 m. > >let um = u_z[z=5000:100@DIN] > >let vm = v_z[z=5000:100@DIN] > > > >Takaya Namba > > > > > > > > > >__________________________________ > >STOP HIV/AIDS. > >Yahoo! JAPAN Redribbon Campaign > >http://pr.mail.yahoo.co.jp/redribbon/ > > > > > > > __________________________________ STOP HIV/AIDS. Yahoo! JAPAN Redribbon Campaign http://pr.mail.yahoo.co.jp/redribbon/

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