In my NO3 output I get values very close to zero but negative (~ -10^-7). I added a couple of lines in Fasham.h, so it would tell me when NO3 is zero or less. The funny thing is that it only finds zeros... but I keep getting small negative numbers in my nc file.
Can there be a rounding problem or similar when writing into nc files?
Any suggestion will be appreciated!
Try using monotonic advection of tracer. Activate TS_MPDATA CPP option. This advection scheme will insure a positive definite scheme. Of course, some times this depends on roundoff.
ROMS output can be set to double precision by activating OUT_DOUBLE. This will generate larger files.