websave downloaded file different than manually downloaded

I'm trying to download some *.nc files direct from some url using websave. It can successfully download the files but the file size is different than the file I manually downloaded from the browser. Here is the file source: http://opendap.co-ops.nos.noaa.gov/index.php?dir=/netcdf/nyofs/201603/ The nc file with size of 1 MB shows only 25 KB with Matlab download.

starting_date = datenum('2016-03-01');  
end_date = datenum('2016-03-02');
tic;
for n =1: end_date-starting_date
    current_date_download = starting_date + n -1;
    for t = 0 : 23
        posext = ['.t',sprintf('%02s',num2str(t)),'z.nc'];
        filename = ['nos.nyofs_fg.stations.nowcast.',datestr(current_date_download,'yyyymmdd'),posext];
        sprintf('processing %s - %02d z download\n',datestr(current_date_download),t)
        url = ['http://opendap.co-ops.nos.noaa.gov/netcdf/nyofs/',datestr(current_date_download,'yyyymm'), ...
          '/',filename];
        sprintf('Downloading %s , please waiting ...\n', url)
        options = weboptions('RequestMethod','post');        
        try
            outfilename = websave(filename, url,options);
            %urlwrite(url,filename)
        catch
            warning('file does not exsit, check url');
        end
    end
end
sprintf('Job successfully finished for downloading nc files!!')
toc;