title: Is it possible to call xarray open_mfdataset on an FTP server?
body: <p>I'm attempting to download a daily ocean temperature reanalysis product (<a href="https://resources.marine.copernicus.eu/?option=com_csw&amp;view=details&amp;product_id=GLOBAL_REANALYSIS_PHY_001_031" rel="nofollow noreferrer">GLORYS2V4 from CMEMS</a>) for the North Atlantic, but the only download option is FTP access with large (2GB) global files. Is it possible to use open_mfdataset on an FTP directory to take the subset I need without downloading all the data to my local machine? If so, how would I set up the path or url?</p>
  <p>Currently I'm connecting to the FTP and then trying to give xarray the url, but it's interpreting the url as a path in my working directory. E.g. if I were trying to open just one file for January 1, 2000:</p>
  <pre><code>ftp = FTP(&quot;my.cmems-du.eu&quot;, username, password)
  sample_directory = '/Core/GLOBAL_REANALYSIS_PHY_001_031/global-reanalysis-phy-001-031-grepv2-daily/2000/01'
  ftp.cwd (sample_directory)
  
  ftp_path = 'ftp://my.cmems-du.eu/Core/GLOBAL_REANALYSIS_PHY_001_031/global-reanalysis-phy-001-031-grepv2-daily/2000/01/grepv2_daily_20000101.nc'
  ds = xr.open_dataset (ftp_path)
  </code></pre>
  <p>This yields a FileNotFoundError: <code>[Errno 2] No such file or directory: b'U:\\Documents\\conda_dir\\ftp:\\my.cmems-du.eu\\Core\\GLOBAL_REANALYSIS_PHY_001_031\\global-reanalysis-phy-001-031-grepv2-daily\\2000\\01\\grepv2_daily_20000101.nc'</code> where 'U:\Documents\conda_dir' is my working directory.</p>