the forcing fields from input and output are not the same

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xiaozhu557
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the forcing fields from input and output are not the same

#1 Post by xiaozhu557 »

Hello,
I have tried to compare the forcing field from input with output for the variable shflux (surface net heat flux). The followed three figures are the fields of input, output, and difference between of them on the first time step (ocean_time=0). I can not understand why they are not the same? I have not defined bulk_flux.

Anyone can tell me the reason or what's the problem with it? Thanks.
Attachments
differences between the output and input
differences between the output and input
the shflux fields from output history file.
the shflux fields from output history file.
the shflux fields from input forcing file.
the shflux fields from input forcing file.

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kate
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Re: the forcing fields from input and output are not the sa

#2 Post by kate »

ROMS is interpolating in time and space to obtain its field. Is your input field at exactly the starting time for your run?

xiaozhu557
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Location: nmefc

Re: the forcing fields from input and output are not the sa

#3 Post by xiaozhu557 »

kate wrote:ROMS is interpolating in time and space to obtain its field. Is your input field at exactly the starting time for your run?
Yes, it is. They are both for ocean_time=0.

xiaozhu557
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Re: the forcing fields from input and output are not the sa

#4 Post by xiaozhu557 »

kate wrote:ROMS is interpolating in time and space to obtain its field. Is your input field at exactly the starting time for your run?
Hi, Kate, could you continue to follow my question? Thanks a lot.

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wilkin
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Re: the forcing fields from input and output are not the sa

#5 Post by wilkin »

Might you have #define QCORRECTION ?

Are you letting ROMS regrid the input, or is it already interpolated to the grid?
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kate
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Re: the forcing fields from input and output are not the sa

#6 Post by kate »

It looks to me like he is letting ROMS regrid it, but that shouldn't introduce those structures that look like eddies.

Are you sure you want my two cents? I'd say watch in the debugger to see what's going on.

xiaozhu557
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Re: the forcing fields from input and output are not the sa

#7 Post by xiaozhu557 »

Thanks for your kindly responding. I am sorry for my later.

I forget that I have #defined QCORRECTION. I think that should be the reason for my problem.

But I would like to know how should I set the model to let it regrid input? I have not defined nesting.

Thanks.

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kate
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Re: the forcing fields from input and output are not the sa

#8 Post by kate »

The regridding of the forcing fields has nothing to do with nesting. The regridding was added so that global forcing fields could be used directly. ROMS will decide to regrid if the forcing fields are dimensioned differently from your model grid. If your forcing fields are dimensioned say 360x180, it would be a really bad idea to build a regional grid of the same size. This has been documented:

https://www.myroms.org/wiki/index.php/F ... forcing.3F

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