My ROMS is v3.4, ticket 512, with only one tidal component-M2. These days, I want to obtain the tidal residual currents in my region, so I have tried the following method as supposed as before in the forum.
(1) the simple method of time average by:
set DT == 216.0104d0
NAVG == 2070
NDEFAVG == 20700
in the ocean.in file and define 'AVERAGES' and 'AVERAGES_DETIDE' in the cpp file.
then after 60 days simulation, the residual flow can be extracted from the 'u' and 'v' of the file avg.nc as following:
M2 residual flow in the Bohai Sea, plotted by u and v in the avg.nc.
or by 'u_detided' and 'v_detided' since I have also defined 'AVERAGES_DETIDE' in the cpp file. The results as follows:
M2 residual flow in the Bohai Sea, plotted by u_detided and v_detided in the avg.nc. setting: DT == 216.0104d0; NAVG == 2070; AVERAGES and AVERAGES_DETIDE.
The results from different time index remain nearly constant.
I thought that the 'u'/'v' and 'u_detided'/'v_detided' in the avg.nc should have been similar to each other on the basis of my cpp configuration. But they are different completely. It looks like the u_detided/v_detides results are residuals of the M2 residual flow (u/v) by ROMS filtering methods.
So, my first question: what exact means of the results of 'u_detided' and 'v_detided' (they are very small but not zero) in the above case?
The second question is: how to set dt and NAVG perfectly if we want to extract non-tidal flows when simulating 2 or more tidal constitutes?
Thank you in advance!
zhou
Thank you all!