Question about the tidal forcing file

General scientific issues regarding ROMS

Moderators: arango, robertson

Post Reply
Message
Author
xupeng66
Posts: 79
Joined: Sat Mar 06, 2010 3:38 pm
Location: University of Washington

Question about the tidal forcing file

#1 Unread post by xupeng66 »

Hi All,

I have a question regarding the tidal ellipse inclination angle "tide_Cangle" in the forcing file. I am wondering if "tide_Cangle" is the angle between the semi-major axis and east or it is the angle between the semi-major axis and the xi direction.

Thanks

Guangyu

drivas
Posts: 33
Joined: Tue Aug 28, 2007 8:31 pm
Location: CICESE

Re: Question about the tidal forcing file

#2 Unread post by drivas »

Hello,
I just found this post which, unfortunately, doesn't show any answer. What was your conclusion? Is it the angle with respect to the east or respect to the xi coordinate?
Regards,
drivas

jcwarner
Posts: 1198
Joined: Wed Dec 31, 2003 6:16 pm
Location: USGS, USA

Re: Question about the tidal forcing file

#3 Unread post by jcwarner »

i have not looked at the tides files in a long time, but in our tides tools m file we have:

cangleID = netcdf.defVar(nc_init,'tide_Cangle','double',[xrhodimID erhodimID ntidedimID]);
netcdf.putAtt(nc_init,cangleID,'long_name','tidal current inclination angle');
netcdf.putAtt(nc_init,cangleID,'units','degrees between semi-major axis and East');
netcdf.putAtt(nc_init,cangleID,'field','tide_Cangle, scalar, series');

jcwarner
Posts: 1198
Joined: Wed Dec 31, 2003 6:16 pm
Location: USGS, USA

Re: Question about the tidal forcing file

#4 Unread post by jcwarner »

and then in set tides you have stuff like:

omega=cff/Tperiod(itide)
DO j=MIN(JstrR,Jstr-1),JendR
DO i=MIN(IstrR,Istr-1),IendR
angle=UV_Tangle(i,j,itide)-angler(i,j) <--------- here it corrects for the grid angle
Cangle=COS(angle)
Sangle=SIN(angle)
phase=omega-UV_Tphase(i,j,itide)
Cphase=COS(phase)
Sphase=SIN(phase)
Uwrk(i,j)=UV_Tmajor(i,j,itide)*Cangle*Cphase- &
& UV_Tminor(i,j,itide)*Sangle*Sphase
Vwrk(i,j)=UV_Tmajor(i,j,itide)*Sangle*Cphase+ &
& UV_Tminor(i,j,itide)*Cangle*Sphase
.....

Post Reply