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% |
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% [MLD] = compute_MLD(SNAPSHOT) |
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% |
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% Here we compute the Mixed Layer Depth as: |
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% MLD = min depth for which : ST > ST(SSS,SST-0.8,p0) |
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% |
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% where: |
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% ST is potential density (kg/m3) |
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% SST the Sea Surface Temperature (oC) |
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% SSS the Sea Surface Salinity (PSU-35) |
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% p0 the Sea Level Pressure (mb) |
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% EKL is the Ekman layer depth (m, positive) |
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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_THETA>.<netcdf_domain>.<netcdf_suff> |
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% ./netcdf-files/<SNAPSHOT>/<netcdf_SALTanom>.<netcdf_domain>.<netcdf_suff> |
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% OUTPUT |
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% ./netcdf-files/<SNAPSHOT>/<netcdf_MLD>.<netcdf_domain>.<netcdf_suff> |
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% |
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% with netcdf_* as global variables |
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% netcdf_MLD = 'MLD' by default |
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% |
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% Rq: This method leads to a MLD deeper than KPPmld in the middle of the |
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% ocean, and shallower along the coast. |
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% |
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% 09/20/06 |
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% gmaze@mit.edu |
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|
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function varargout = compute_MLD(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_SIGMATHETA netcdf_THETA netcdf_SALTanom netcdf_MLD |
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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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filT = netcdf_THETA; |
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filS = netcdf_SALTanom; |
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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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ST = ncST{4}(:,:,:); |
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[STlon STlat STdpt] = coordfromnc(ncST); |
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|
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ferfile = strcat(pathname,sla,snapshot,sla,filT,'.',netcdf_domain,'.',ext); |
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ncT = netcdf(ferfile,'nowrite'); |
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SST = ncT{4}(1,:,:); |
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[Tlon Tlat Tdpt] = coordfromnc(ncT); |
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|
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ferfile = strcat(pathname,sla,snapshot,sla,filS,'.',netcdf_domain,'.',ext); |
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ncS = netcdf(ferfile,'nowrite'); |
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SSS = ncS{4}(1,:,:); |
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[Slon Slat Sdpt] = coordfromnc(ncS); |
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|
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|
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%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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% COMPUTE The Mixed Layer Depth: |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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if toshow, disp('pre-allocate'), end |
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nx = length(STlon); |
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ny = length(STlat); |
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SST08 = SST - 0.8; |
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SSS = SSS + 35; |
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Surfadens08 = densjmd95(SSS,SST08,(0.09998*9.81*Tdpt(1))*ones(ny,nx))-1000; |
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MLD = zeros(size(ST,2),size(ST,3)); |
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|
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if toshow, disp('get MLD'), end |
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for iy = 1 : size(ST,2) |
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for ix = 1 : size(ST,3) |
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mm = find( squeeze(ST(:,iy,ix)) > Surfadens08(iy,ix) ); |
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if ~isempty(mm) |
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MLD(iy,ix) = STdpt(min(mm)); |
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end |
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%end |
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end |
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end |
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|
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MLD(isnan(squeeze(ST(1,:,:)))) = NaN; |
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|
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|
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%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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% Ensure we have the right sign (positive) |
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mm = nanmean(nanmean(MLD,1)); |
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if mm <= 0 |
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MLD = -MLD; |
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end |
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|
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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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if ~isempty('netcdf_MLD') |
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netfil = netcdf_MLD; |
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else |
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netfil = 'MLD'; |
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end |
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units = 'm'; |
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ncid = 'MLD'; |
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longname = 'Mixed Layer Depth'; |
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uniquename = 'MLD'; |
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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; |
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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'}(:) = STlon; |
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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; |
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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}(:,:,:) = MLD; |
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|
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nc=close(nc); |
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close(ncST); |
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close(ncS); |
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close(ncT); |
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|
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|
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% Output: |
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output = struct('MLD',MLD,'lat',STlat,'lon',STlon); |
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switch nargout |
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case 1 |
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varargout(1) = {output}; |
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end |
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