tide time corrections

Discussion of how to use ROMS on different regional and basin scale applications.

Moderators: arango, robertson

Post Reply
Message
Author
sjaybbxo
Posts: 1
Joined: Fri Jan 25, 2019 5:23 pm
Location: Chonnam University

tide time corrections

#1 Post by sjaybbxo » Fri Apr 12, 2019 1:48 pm

Hi everyone,

I have a problem in running my model. I created a tide forcing file which runs from January 06 2016.
I set the DSTART, TIDE_START, and TIME_REF as follows :

DSTART = 0.0d0 ! days
TIDE_START = 0.0d0 ! days
TIME_REF = 20160101.00 ! yyyymmdd.dd

However, compared to the tide level of my model and the observation data, the spring tide is about 7 days different.
So, I reset the DSTART, TIDE_START, and TIME_REF as follows :

DSTART = 0.0d0 ! days
TIDE_START = 0.0d0 ! days
TIME_REF = 20160106.00 ! yyyymmdd.dd

But the result was the same as last time.
How do I set the time to match the observations?

Thanks.

jcwarner
Posts: 816
Joined: Wed Dec 31, 2003 6:16 pm
Location: USGS, USA

Re: tide time corrections

#2 Post by jcwarner » Fri Apr 12, 2019 7:43 pm

set_tides.F

cff=2.0_r8*pi*(time(ng)-tide_start*day2sec)
DO itide=1,NTC
...
omega=cff/Tperiod(itide)
DO, .. DO ...
Etide(i,j)=Etide(i,j)+ &
& ramp*SSH_Tamp(i,j,itide)* &
& COS(omega-SSH_Tphase(i,j,itide))


so it takes ocean_time-tide_start to get omega. if you have dstart and tide_start but start at 0, then it will be the same.How about:
DSTART = 5.0d0 ! days
TIDE_START = 0.0d0 ! days
TIME_REF = 20160101.00 ! yyyymmdd.dd
??

Post Reply