I’m attempting an AMIP timeslice run on Monsoon (u-ck729) using timeslice Ancils and emissions files. Atmos_main starts but after about 100 timsteps (~36 - 42 hours model time), I start getting the following message in pe_output:
 Negatives - exceeds maxneg
 Too many negatives (>2000) in spimpmjp (iter 7) lon= 11 lat= 0; halving step
This causes the model to run very slowly and eventually time out on the wallclock. It only occurs on some timesteps as well.
After some testing, I think this is a problem with my emission files as the model runs fine when I use standard CMIP6 emission files. I don’t think it is a problem with the branch either because other runs using different emissions but the same branch and chemistry work fine. I have checked my emission input files and there do not appear to be any negative values in them (the minimum value in all cases is 0).
Have you seen anything like this before? Would you recommend any other tests to diagnose this problem?