weird tidal elevation problem

[pengjia]

When I run a 2-D tides-only case (zero-sustr,svstr), the tidal elevations during flood are perfect compared with the predicated at NOAA tidal gauge, but during ebb the water levels are always higher than the NOAA's (the amplitude is smaller). I assume it's due to bathymetry (i.e. minimum water depth), but haven't figured out how bathymetry influences the tidal elevation. Can you kindly point it out? Thanks.

[kate]

Maybe if you tell us more about what you are doing? Do you have WET_DRY on? What is your minimum depth? What sort of spatial scales are you talking about?