DSTART, TIDE_START & TIME_REF in the *.in file

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lalvarez
Posts: 100
Joined: Wed Feb 03, 2010 6:59 pm
Location: Universidad Autonoma de Baja California Sur

DSTART, TIDE_START & TIME_REF in the *.in file

#1 Post by lalvarez » Tue Sep 01, 2015 4:50 pm

Hello to All

I have a doubt about DSTART, TIDE_START & TIME_REF.

My forcing files date start on january 1-1996 and end on april 30-1997, and I want to run the model from may 1-1996 to april 30-1997. If my TIME_REF = 19960101.0, then what must be the correct assigments for DSTART and TIDE_START?

DSTART = 0.0d0 ! days
TIDE_START = 0.0d0 ! yyyymmdd.dd
TIME_REF = 19960101.0d0 ! yyyymmdd.dd

Thanks in advance
Leo

miguel.solano
Posts: 11
Joined: Mon Jan 30, 2012 8:02 pm
Location: University of Texas at Dallas

Re: DSTART, TIDE_START & TIME_REF in the *.in file

#2 Post by miguel.solano » Wed Sep 02, 2015 3:02 pm

Hello,
The way I understand it is:

dstart = time_start - time_ref
tide_start = tide_base_date - time_start

Where time_ref='19960101', time_start='19960501' and tide_base_date is the base date you used when generating the tide forcing file. Basically if your tide base date pre-dates your initialization time (time_start) then your tide start should be negative.

I used to have a lot of confusion when I started modeling in ROMS, but hopefully I am right about this now. What used to confuse me is that tide_start does not depend on dstart, which is easy to realize once you use a different time_ref, in which case dstart would change but it would not affect the value of tide_start.

Perhaps someone with more experience can confirm this...

https://www.myroms.org/wiki/tide_start

-Miguel

lalvarez
Posts: 100
Joined: Wed Feb 03, 2010 6:59 pm
Location: Universidad Autonoma de Baja California Sur

Re: DSTART, TIDE_START & TIME_REF in the *.in file

#3 Post by lalvarez » Tue Nov 24, 2015 2:54 pm

Hi Miguel

Thanks a lot for your replay, i'll take that in account

Have a nice day

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