Elevation decreased at all of grids except outermost grid at the boundary

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theresiaao

Elevation decreased at all of grids except outermost grid at the boundary

#1 Unread post by theresiaao »

Hi all, I need help

I have problem on my model result,
first of all I'm doing a hydrodynamic model with a nested model which is planned to be made of 4 nested domains
The first domain has ran successfully, now I'm trying to run the second nested model domain

My first domain is Indonesia as a whole, and I do nesting for the second domain in the Lesser Sunda Islands
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I have struggled the n-th problems of blow up since my model area covers many narrow straits,
let's say the place where the blow up occurs is in the westernmost strait, then I overcome this by changing the bathymetry value in the strait to be deeper
then the blow up moved to another strait to the east, and I did the same thing by increasing the bathymetry value in that strait and also changing the minimum depth on the island around the strait (by default my mininum depth is 20 meters, but because of this problem I raise the minimum depth only on any land near the strait manually)
I did that for other straits (because blow ups always move to the next strait further east)

this is Lesser Sunda Islands
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after doing this over and over again, finally my model (second nested domain) can run smoothly until the end without blow up

but the problem is that the elevation value in my model decreases over time
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I have checked the elevation value of the second nested domain all over the model
I overlayed the elevation value from the 1st and 2nd domain to check the concistency because I think there is a problem when making contact between domains 1 and 2, but I found the elevation value from Domain 2 decreases all over the place except at the outermost grid at the boundary compared to elevation value from Domain 1

I ran out of idea where's the problem and how to solve this,
I really need help for this problem

I'm really looking forward to an answer that might be a solution to this problem

Thank you

Sincerely,
Theresia

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wilkin
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Location: Rutgers University
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Re: Elevation decreased at all of grids except outermost grid at the boundary

#2 Unread post by wilkin »

Do the bathymetries of the parent and child grids match for several grid cells near to the edge of the child grid? This is recommended so that the volumes of the grids match in the transition region.

Have you compared one-way and two-way nesting to see if the issue occurs in both?

Note that the nesting code was updated 3 months ago. https://www.myroms.org/projects/src/ticket/887
Make sure you have this updated version running.
John Wilkin: DMCS Rutgers University
71 Dudley Rd, New Brunswick, NJ 08901-8521, USA. ph: 609-630-0559 jwilkin@rutgers.edu

theresiaao

Re: Elevation decreased at all of grids except outermost grid at the boundary

#3 Unread post by theresiaao »

sorry for the late respon, thank you so much for the solution

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