The netCDF-CF conventions and virtually all mathematical analyses define latitude increasing from south to north. Image processing conventions, which were to some degree adopted into GIS standards define the origin of an image at the upper left, instead of the lower left (a legacy of CRT sweep logic in the electronics of old ??). Therein lies the conflict.
In Ferret you can use the /ORDER qualifier on the SET DATA command and the /VLIMITS qualifiers on the plotting commands to flip the direction of latitude if it is encoded in a reversed way from your needs.
On 6/29/2013 7:34 PM, Boyin Huang - NOAA Federal wrote: