I am working on the implementation of Ensemble Optimal Interpolation (ENOI) in a regional domain of ROMS in the North Pacific Ocean (see figure) .
I am using 6-hourly Hycom GLBy 0.08 T/S/U/V/SSH in the open boundaries of my ROMS regional grid. I am using the Chapman condition (Cha) on SSH and the Flather condition (Fla) on the external velocities. I also use the RadNud condition on the internal velocities and on T/S. In the surface I use the BULK fluxes, which are computed from CFSR v2.1 3-hourly variables. I am using air temp at 2 m, wind U/V at 10 m, specific humidity at 2m , air pressure at MSL, precipitation rate, and net long/short radiations.
This is working well. After 8 years of integration the results are looking good and the model is stable. However, the long-term mean of SSH shows higher values near the open boundaries, and smaller values in the middle of the domain. This is causing a negative impact in the DATA Assimilation.
When I run ROMS with ENOI, the results show higher errors near the open boundaries (see the figure).
I suspect that I need to correct the HYCOM SSH, so it will have the same MSL as the satellite along-track SLA that I am assimilating, before I impose hycom SSH in the boundaries.
The question is: Does anybody in the forum has a similar problem ?
and second question: Does anybody know where I will get the Global Hycom long-term mean sea level ?
I already tried the hycom forum, but I didn't get any answer from them.
If this is a topic which have already been addressed in the forum, please let me know. If not, I hope this will create a discussion that will be useful to other user too.
Thank You .
Ivan
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