[MITgcm-support] definition of PHIBOT in ECCO 4

[Noel Bartlow]

Hi,

I am new to oceanography and ECCO (I am a geodesist).  I am attempting to model some GPS displacements caused by ocean loading and would like to use the ocean bottom pressure, PHIBOT, from ECCO 4.  Forgive my naive questions, but I can’t seem to find anywhere an exact definition for PHIBOT.  My guess is that the actual bottom pressure is defined as:

P= g*RhoConst*ETAN+PHIBOT*RhoConst

But I am not sure.  Is ETAN the correct ocean height to use, or should it be RCENTER?  One varies in time and the other doesn’t.  Should I be taking into account the RhoAnomaly and integrating over the water column?  What about the fresh water flux (SIatmFW), is that taken into account or is ocean mass or volume conserved in PHIBOT?  Does PHIBOT include atmospheric pressure, or is it relative to the ocean surface?  I am interested in variations over time, especially seasonal variations, so I need to take these into account.  

Thanks to anyone who can help me figure this out.

____________________________________________
Noel Bartlow
Miles Postdoctoral Fellow
Institute of Geophysics and Planetary Physics
Scripps Institution of Oceanography
University of California, San Diego
Phone: (858) 534-4643