nccopy -k 4 -d 6 -m 50000000 "http://tds.marine.rutgers.edu/thredds/dodsC/roms/ecb/ches/fengjgr2015/his" fengjgr2015.nc
#nc3tonc4 --chunk=5 "http://tds.marine.rutgers.edu/thredds/dodsC/roms/ecb/ches/fengjgr2015/his" fengjgr2015.nc