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COAWST modeling system git repository
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Question Regarding ocean.in File Settings #268

Open wjlyx opened 5 months ago

wjlyx commented 5 months ago

Hello everyone,

I have a question regarding the ocean.in file settings in COAWSTv3.8. In the ROMS Sandy case, the DSTART=56228.5d0, TIDE_START= 56228.0d0, and TIME_REF=18581117.0d0 , while in the JOE_TC case, all three parameters are set to 0. I don't understand why there is a difference between these cases. If I want to simulate ocean conditions from July 1, 2015, to July 11, 2015, how should I set these three parameters?

jcwarner-usgs commented 5 months ago

The JOE case is idealized and is based on a time starting from 0. The Sandy case is realistic (very coarse grid, but realistic) and we go through all the steps in the manual how to get ncei winds, hycom bndry data etc and all that needs to be on consistent times. So if you are doing a real case, use the Sandy as an example.

if you set time ref as 1858 11 17 (nov 17, 1858) then in matlab datenum(1858,11,17) = 678942

So if you have winds on July 1, 2015, that date would be datenum(2015, 07,1) - datenum(1858,11,17) = 57204 So time of 57204 is really July 1, 2015 beccause of how you set timeref. You can pick other time refs. up to you . more info at the botom of the ocean.in or ask on the Rutgers forum.

The tide start is the date you use to compute the tidal phases. That is set wehn you create the tide forcings file. See create_roms_tides as an example, or look on the Rutgers site.

wjlyx commented 5 months ago

The JOE case is idealized and is based on a time starting from 0. The Sandy case is realistic (very coarse grid, but realistic) and we go through all the steps in the manual how to get ncei winds, hycom bndry data etc and all that needs to be on consistent times. So if you are doing a real case, use the Sandy as an example.

if you set time ref as 1858 11 17 (nov 17, 1858) then in matlab datenum(1858,11,17) = 678942

So if you have winds on July 1, 2015, that date would be datenum(2015, 07,1) - datenum(1858,11,17) = 57204 So time of 57204 is really July 1, 2015 beccause of how you set timeref. You can pick other time refs. up to you . more info at the botom of the ocean.in or ask on the Rutgers forum.

The tide start is the date you use to compute the tidal phases. That is set wehn you create the tide forcings file. See create_roms_tides as an example, or look on the Rutgers site. Thank you very much for your reply.