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% |
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% [EKL] = compute_EKL(SNAPSHOT) |
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% |
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% Here we compute the Ekmal Layer Depth as: |
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% EKL = 0.7 sqrt( |TAU|/RHO )/f |
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% |
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% where: |
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% TAU is the amplitude of the surface wind-stress (N/m2) |
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% RHO is the density of seawater (kg/m3) |
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% f is the Coriolis parameter (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_RHO>.<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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% OUTPUT |
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% ./netcdf-files/<SNAPSHOT>/<netcdf_EKL>.<netcdf_domain>.<netcdf_suff> |
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% |
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% with netcdf_* as global variables |
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% netcdf_EKL = 'EKL' by default |
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% |
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% 08/16/06 |
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% gmaze@mit.edu |
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|
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function varargout = compute_EKL(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_RHO netcdf_EKL |
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pv_checkpath |
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global EKL Tx Ty TAU RHO f |
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|
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|
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% NETCDF file name: |
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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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|
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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,filTx,'.',netcdf_domain,'.',ext); |
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ncTx = netcdf(ferfile,'nowrite'); |
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Tx = ncTx{4}(1,:,:); |
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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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Ty = ncTy{4}(1,:,:); |
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[Tylon Tylat Tydpt] = coordfromnc(ncTy); |
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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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[RHOlon RHOlat RHOdpt] = coordfromnc(ncRHO); |
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|
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|
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%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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% Get EKL |
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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(RHOlon); |
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ny = length(RHOlat); |
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nz = length(RHOdpt); |
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|
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% Pre-allocate: |
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if toshow, disp('pre-allocate'), end |
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EKL = zeros(ny,nx); |
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|
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% Planetary vorticity: |
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f = 2*(2*pi/86400)*sin(RHOlat*pi/180); |
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[a f c]=meshgrid(RHOlon,f,RHOdpt); clear a c |
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f = permute(f,[3 1 2]); |
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f = squeeze(f(1,:,:)); |
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|
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% Windstress amplitude: |
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TAU = sqrt( Tx.^2 + Ty.^2 ); |
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|
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% Ekman Layer Depth: |
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EKL = 0.7* sqrt(TAU ./ RHO) ./f; |
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%EKL = 1.7975 * sqrt( TAU ./ RHO ./ f ); |
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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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if ~isempty('netcdf_EKL') |
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netfil = netcdf_EKL; |
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else |
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netfil = 'EKL'; |
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end |
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units = 'm'; |
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ncid = 'EKL'; |
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longname = 'Ekman Layer Depth'; |
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uniquename = 'EKL'; |
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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(RHOlon) ; |
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ny = length(RHOlat) ; |
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nz = 1 ; |
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|
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nc('X') = nx; |
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nc('Y') = ny; |
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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'}(:) = RHOlon; |
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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'}(:) = RHOlat; |
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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'}(:) = RHOdpt(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}(:,:,:) = EKL; |
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|
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nc=close(nc); |
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|
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|
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|
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% Output: |
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output = struct('EKL',EKL,'lat',RHOlat,'lon',RHOlon); |
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switch nargout |
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case 1 |
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varargout(1) = {output}; |
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end |