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% |
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% [] = compute_JFz(SNAPSHOT) |
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% |
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% Here we compute the PV flux due to frictionnal forces as |
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% JFz = ( TAUx * dSIGMATHETA/dy - TAUy * dSIGMATHETA/dx ) / RHO / EKL |
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% |
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% where: |
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% TAU is the surface wind-stress (N/m2) |
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% SIGMATHETA is the potential density (kg/m3) |
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% RHO is the density (kg/m3) |
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% EKL is the Ekman layer depth (m) |
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% |
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% Files names are: |
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% INPUT: |
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% ./netcdf-files/<SNAPSHOT>/<netcdf_SIGMATHETA>.<netcdf_domain>.<netcdf_suff> |
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% ./netcdf-files/<SNAPSHOT>/<netcdf_TAUX>.<netcdf_domain>.<netcdf_suff> |
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% ./netcdf-files/<SNAPSHOT>/<netcdf_TAUY>.<netcdf_domain>.<netcdf_suff> |
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% ./netcdf-files/<SNAPSHOT>/<netcdf_RHO>.<netcdf_domain>.<netcdf_suff> |
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% ./netcdf-files/<SNAPSHOT>/<netcdf_EKL>.<netcdf_domain>.<netcdf_suff> |
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% OUTPUT: |
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% ./netcdf-files/<SNAPSHOT>/JFz.<netcdf_domain>.<netcdf_suff> |
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% |
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% with netcdf_* as global variables |
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% |
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% 06/27/06 |
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% gmaze@mit.edu |
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|
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function compute_JFz(snapshot) |
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|
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global sla toshow |
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global netcdf_suff netcdf_domain |
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global netcdf_TAUX netcdf_TAUY netcdf_SIGMATHETA netcdf_EKL netcdf_RHO |
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pv_checkpath |
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|
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|
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% NETCDF file name: |
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filST = netcdf_SIGMATHETA; |
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filTx = netcdf_TAUX; |
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filTy = netcdf_TAUY; |
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filRHO = netcdf_RHO; |
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filH = netcdf_EKL; |
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|
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% Path and extension to find them: |
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pathname = strcat('netcdf-files',sla); |
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ext = netcdf_suff; |
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|
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% Load files: |
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ferfile = strcat(pathname,sla,snapshot,sla,filST,'.',netcdf_domain,'.',ext); |
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ncST = netcdf(ferfile,'nowrite'); |
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[STlon STlat STdpt] = coordfromnc(ncST); |
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|
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ferfile = strcat(pathname,sla,snapshot,sla,filTx,'.',netcdf_domain,'.',ext); |
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ncTx = netcdf(ferfile,'nowrite'); |
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ferfile = strcat(pathname,sla,snapshot,sla,filTy,'.',netcdf_domain,'.',ext); |
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ncTy = netcdf(ferfile,'nowrite'); |
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|
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ferfile = strcat(pathname,sla,snapshot,sla,filRHO,'.',netcdf_domain,'.',ext); |
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ncRHO = netcdf(ferfile,'nowrite'); |
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RHO = ncRHO{4}(1,:,:); |
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|
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ferfile = strcat(pathname,sla,snapshot,sla,filH,'.',netcdf_domain,'.',ext); |
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ncH = netcdf(ferfile,'nowrite'); |
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EKL = ncH{4}(1,:,:); |
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|
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|
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|
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|
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%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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% First term |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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|
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% Dim: |
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if toshow, disp('dim'), end |
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nx = length(STlon) ; |
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ny = length(STlat) - 1 ; |
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nz = length(STdpt); |
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|
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% Pre-allocate: |
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if toshow, disp('pre-allocate'), end |
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dSIGMATHETAdy = zeros(nz,ny-1,nx).*NaN; |
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dy = zeros(1,ny).*NaN; |
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STup = zeros(nz,ny); |
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STdw = zeros(nz,ny); |
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|
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% Meridional gradient of SIGMATHETA: |
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if toshow, disp('grad'), end |
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% Assuming the grid is regular, dy is independent of x: |
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[dy b] = meshgrid( m_lldist([1 1]*STlon(1),STlat(1:ny+1) ), STdpt ) ; clear b |
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for ix = 1 : nx |
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if toshow, disp(strcat(num2str(ix),'/',num2str(nx))), end |
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STup = squeeze(ncST{4}(:,2:ny+1,ix)); |
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STdw = squeeze(ncST{4}(:,1:ny,ix)); |
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dSTdy = ( STup - STdw ) ./ dy; |
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% Change horizontal grid point definition to fit with SIGMATHETA: |
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dSTdy = ( dSTdy(:,1:ny-1) + dSTdy(:,2:ny) )./2; |
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dSIGMATHETAdy(:,:,ix) = dSTdy; |
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end %for iy |
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|
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% Make TAUx having same limits: |
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TAUx = ncTx{4}(1,2:ny,:); |
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|
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% Compute first term: TAUx * dSIGMATHETA/dy |
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iz = 1; |
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JFz_a = TAUx .* squeeze(dSIGMATHETAdy(iz,:,:)) ; |
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|
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|
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%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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% Second term |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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|
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% Dim: |
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if toshow, disp('dim'), end |
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nx = length(STlon) - 1; |
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ny = length(STlat) ; |
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nz = length(STdpt) ; |
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|
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% Pre-allocate: |
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if toshow, disp('pre-allocate'), end |
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dSIGMATHETAdx = zeros(nz,ny,nx-1).*NaN; |
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dx = zeros(1,nx).*NaN; |
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STup = zeros(nz,nx); |
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STdw = zeros(nz,nx); |
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|
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% Zonal gradient of SIGMATHETA |
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if toshow, disp('grad'), end |
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for iy = 1 : ny |
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if toshow, disp(strcat(num2str(iy),'/',num2str(ny))), end |
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[dx b] = meshgrid( m_lldist(STlon(1:nx+1),[1 1]*STlat(iy)), STdpt ) ; clear b |
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STup = squeeze(ncST{4}(:,iy,2:nx+1)); |
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STdw = squeeze(ncST{4}(:,iy,1:nx)); |
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dSTdx = ( STup - STdw ) ./ dx; |
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% Change horizontal grid point definition to fit with SIGMATHETA: |
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dSTdx = ( dSTdx(:,1:nx-1) + dSTdx(:,2:nx) )./2; |
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dSIGMATHETAdx(:,iy,:) = dSTdx; |
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end %for iy |
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|
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% Make TAUy having same limits: |
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TAUy = ncTy{4}(1,:,2:nx); |
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|
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% Compute second term: TAUy * dSIGMATHETA/dx |
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iz = 1; |
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JFz_b = TAUy .* squeeze(dSIGMATHETAdx(iz,:,:)) ; |
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|
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|
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|
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%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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% Finish ... |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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% Then make all terms having same limits: |
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nx = length(STlon) ; |
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ny = length(STlat) ; |
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nz = length(STdpt) ; |
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JFz_a = squeeze(JFz_a(:,2:nx-1)); |
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JFz_b = squeeze(JFz_b(2:ny-1,:)); |
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delta_e = squeeze(EKL(2:ny-1,2:nx-1)); |
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rho = squeeze(RHO(2:ny-1,2:nx-1)); |
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|
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% and finish: |
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JFz = (JFz_a - JFz_b)./delta_e./rho; |
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|
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|
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%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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% Record |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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if toshow, disp('record'), end |
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|
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% General informations: |
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netfil = 'JFz'; |
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units = 'kg/m3/s2'; |
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ncid = 'JFz'; |
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longname = 'Vertical PV flux due to frictional forces'; |
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uniquename = 'JFz'; |
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|
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% Open output file: |
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nc = netcdf(strcat(pathname,sla,snapshot,sla,netfil,'.',netcdf_domain,'.',ext),'clobber'); |
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|
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% Define axis: |
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nx = length(STlon) ; |
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ny = length(STlat) ; |
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nz = 1 ; |
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|
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nc('X') = nx-2; |
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nc('Y') = ny-2; |
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nc('Z') = nz; |
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|
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nc{'X'} = ncfloat('X'); |
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nc{'X'}.uniquename = ncchar('X'); |
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nc{'X'}.long_name = ncchar('longitude'); |
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nc{'X'}.gridtype = nclong(0); |
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nc{'X'}.units = ncchar('degrees_east'); |
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nc{'X'}(:) = STlon(2:nx-1); |
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|
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nc{'Y'} = ncfloat('Y'); |
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nc{'Y'}.uniquename = ncchar('Y'); |
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nc{'Y'}.long_name = ncchar('latitude'); |
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nc{'Y'}.gridtype = nclong(0); |
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nc{'Y'}.units = ncchar('degrees_north'); |
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nc{'Y'}(:) = STlat(2:ny-1); |
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|
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nc{'Z'} = ncfloat('Z'); |
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nc{'Z'}.uniquename = ncchar('Z'); |
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nc{'Z'}.long_name = ncchar('depth'); |
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nc{'Z'}.gridtype = nclong(0); |
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nc{'Z'}.units = ncchar('m'); |
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nc{'Z'}(:) = STdpt(1); |
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|
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% And main field: |
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nc{ncid} = ncfloat('Z', 'Y', 'X'); |
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nc{ncid}.units = ncchar(units); |
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nc{ncid}.missing_value = ncfloat(NaN); |
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nc{ncid}.FillValue_ = ncfloat(NaN); |
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nc{ncid}.longname = ncchar(longname); |
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nc{ncid}.uniquename = ncchar(uniquename); |
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nc{ncid}(:,:,:) = JFz; |
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|
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nc=close(nc); |
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|
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