ulwrf = Upward Longwave Radiation Flux
http://dl.tpac.org.au/thredds/ncss/ncep1/other_gauss/ulwrf.ntat.gauss/ulwrf.ntat.gauss.1951.nc?latitude=&longitude=&time_start=1951-01-01T00%3A00%3A00Z&time_end=1951-12-31T18%3A00%3A00Z&accept=xml