saving gridded data to netCDF

I have gridded velocity data (u and v components) for mutliple timesteps saved as a .mat file and need to convert them to .nc. When I save the data using the below code, and then read the saved .nc files into my Python code, the data seemed to have been jumbled somehow (see attached figures). How can I ensure that the data are saved to the netCDF on the correct grid?

function save_to_netcdf(ADT)
    % Extract variables
    U_all = ADT.u;
    V_all = ADT.v;
    time_datenum_all = ADT.time; % MATLAB time in datenum format
    latitudes = unique(ADT.y3);
    longitudes = unique(ADT.x3);
    
    % Define lat/lon
    [NbLatitudes, NbLongitudes, numDays] = size(U_all);
    GridDepth = 1;
    LatLon = 2;
    lat_min = min(latitudes(:));
    lon_min = min(longitudes(:));
    lat_max = max(latitudes(:));
    lon_max = max(longitudes(:));
    latlon_step = [(lat_max - lat_min) / (NbLatitudes - 1), (lon_max - lon_min) / (NbLongitudes - 1)];
    
    % Define fill values
    fill_value_int = int32(2147483647);
    fill_value_double = double(1.84467440737096e+19);
    fill_value_float = single(1.844674e+19);
    
    for dayIdx = 1:numDays
        % Extract daily data
        U = U_all(:,:,dayIdx);
        V = V_all(:,:,dayIdx);
        time_datenum = time_datenum_all(dayIdx);
        
        contourf(U);

        % Convert MATLAB datenum to UNIX time (seconds since 1970-01-01)
        time_unix = posixtime(datetime(time_datenum, 'ConvertFrom', 'datenum'));

        % Format the date as a string for the "date" attribute
        date_str = datestr(time_datenum, 'yyyy-mm-dd HH:MM:SS.000000 UTC');

        filename = sprintf('ADT_%s.nc', datestr(time_datenum, 'yyyymmdd'));

        % Create NetCDF file
        ncid = netcdf.create(filename, 'CLOBBER');
        netcdf.putAtt(ncid, netcdf.getConstant('NC_GLOBAL'), 'format', 'NETCDF3_CLASSIC');

        % Define dimensions
        dimLat = netcdf.defDim(ncid, 'NbLatitudes', NbLatitudes);
        dimLon = netcdf.defDim(ncid, 'NbLongitudes', NbLongitudes);
        dimGridDepth = netcdf.defDim(ncid, 'GridDepth', GridDepth);
        dimLatLon = netcdf.defDim(ncid, 'LatLon', LatLon);

        % Define variables
        varLatLon = netcdf.defVar(ncid, 'LatLon', 'NC_INT', dimLatLon);
        netcdf.putAtt(ncid, varLatLon, '_FillValue', fill_value_int);
        netcdf.putAtt(ncid, varLatLon, 'long_name', 'No sense but necessary for some automatic tools');
        netcdf.putAtt(ncid, varLatLon, 'units', 'count');
        
        varLat = netcdf.defVar(ncid, 'NbLatitudes', 'NC_DOUBLE', dimLat);
        netcdf.putAtt(ncid, varLat, '_FillValue', fill_value_double);
        netcdf.putAtt(ncid, varLat, 'long_name', 'Latitudes');
        netcdf.putAtt(ncid, varLat, 'units', 'degrees_north');
        
        varLon = netcdf.defVar(ncid, 'NbLongitudes', 'NC_DOUBLE', dimLon);
        netcdf.putAtt(ncid, varLon, '_FillValue', fill_value_double);
        netcdf.putAtt(ncid, varLon, 'long_name', 'Longitudes');
        netcdf.putAtt(ncid, varLon, 'units', 'degrees_east');
        
        varLatLonMin = netcdf.defVar(ncid, 'LatLonMin', 'NC_DOUBLE', dimLatLon);
        netcdf.putAtt(ncid, varLatLonMin, '_FillValue', fill_value_double);
        netcdf.putAtt(ncid, varLatLonMin, 'long_name', 'Latitude/Longitude of south/ouest corner');
        netcdf.putAtt(ncid, varLatLonMin, 'units', 'degree');
        
        varLatLonStep = netcdf.defVar(ncid, 'LatLonStep', 'NC_DOUBLE', dimLatLon);
        netcdf.putAtt(ncid, varLatLonStep, '_FillValue', fill_value_double);
        netcdf.putAtt(ncid, varLatLonStep, 'long_name', 'latitude/longitude steps');
        netcdf.putAtt(ncid, varLatLonStep, 'units', 'degree');
        
        varU = netcdf.defVar(ncid, 'Grid_0001', 'NC_FLOAT', [dimLon, dimLat]);
        netcdf.putAtt(ncid, varU, '_FillValue', fill_value_float);
        netcdf.putAtt(ncid, varU, 'long_name', 'U');
        netcdf.putAtt(ncid, varU, 'units', 'cm/s');
        netcdf.putAtt(ncid, varU, 'Date_CNES_JD', 21913.0);
        netcdf.putAtt(ncid, varU, 'date', date_str);
        
        varV = netcdf.defVar(ncid, 'Grid_0002', 'NC_FLOAT', [dimLon, dimLat]);
        netcdf.putAtt(ncid, varV, '_FillValue', fill_value_float);
        netcdf.putAtt(ncid, varV, 'long_name', 'V');
        netcdf.putAtt(ncid, varV, 'units', 'cm/s');
        netcdf.putAtt(ncid, varV, 'Date_CNES_JD', 21913.0);
        netcdf.putAtt(ncid, varV, 'date', date_str);
        
        % Global attributes
        netcdf.putAtt(ncid, netcdf.getConstant('NC_GLOBAL'), 'FileType', 'GRID_DOTS_MERCATOR');
        netcdf.putAtt(ncid, netcdf.getConstant('NC_GLOBAL'), 'OriginalName', filename);
        netcdf.putAtt(ncid, netcdf.getConstant('NC_GLOBAL'), 'CreatedBy', 'Generated by MATLAB script, mat2netCDF.m');
        netcdf.putAtt(ncid, netcdf.getConstant('NC_GLOBAL'), 'CreatedOn', datestr(now, 'dd-mmm-yyyy HH:MM:SS:000000'));
        netcdf.putAtt(ncid, netcdf.getConstant('NC_GLOBAL'), 'title', 'Geostrophic Flow from ADT, 150W');

        % End define mode
        netcdf.endDef(ncid);

        % Write data
        netcdf.putVar(ncid, varLatLon, [0 1]);
        netcdf.putVar(ncid, varLat, latitudes);
        netcdf.putVar(ncid, varLon, longitudes);
        netcdf.putVar(ncid, varLatLonMin, [lat_min, lon_min]);
        netcdf.putVar(ncid, varLatLonStep, latlon_step);
        netcdf.putVar(ncid, varU, U);
        netcdf.putVar(ncid, varV, V);

        % Close NetCDF file
        netcdf.close(ncid);
    end
end

[Walter Roberson]

I know that .nc files use row-major storage instead of column-major storage. Experiment with transposing all of the 2D arrays that you write.