Xi Cheng, Did it fail with just this commend, or it failed inside a script? I tried just that command on my Mac, it has no problem. You may just try use NetCDF4 as the format. Wei -------------- next part -------------- An HTML attachment was scrubbed... URL: http://mailman.ucar.edu/pipermail/ncl-talk/attachments/20150122/607d5f71/attachment.html