question about pm concentration

Discussions about the Version 4 concerning the core model simulations
TIAN WANTING
Posts: 16
Joined: Mon Sep 30, 2019 4:55 am

question about pm concentration

Postby TIAN WANTING » Fri Nov 08, 2019 12:44 pm

Hi, Dear all
There are some problems with my Simulation result about pm concentration.
I run the simulation for 24 hours, but the maximum value and minimum value of pm concentration, The difference is very small.
But it's not like this before. I try to change the Emission rates, the results are unchanged.(as the picture shows)
I uploaded my files, i wish someone can give me some suggestions.
thank you very much and looking forward to your reply

Best Regards
Tian
Attachments
Tian.zip
(184.84 KiB) Downloaded 1 time
1.png

Tim
Posts: 836
Joined: Mon May 15, 2017 3:46 pm

Re: question about pm concentration

Postby Tim » Fri Nov 08, 2019 1:12 pm

Hi Tian,

The project database is empty, so the emission rates cannot be checked.
Thee cases should show differences if they have different values in their emission rates.

Best regards,
Tim

TIAN WANTING
Posts: 16
Joined: Mon Sep 30, 2019 4:55 am

Re: question about pm concentration

Postby TIAN WANTING » Sat Nov 09, 2019 9:30 am

Hi, Tim

the emission rate i used like the picture.
and i also tried to change the emission rate, but the results are kind of the same :cry:
Attachments
2.png

TIAN WANTING
Posts: 16
Joined: Mon Sep 30, 2019 4:55 am

Re: question about pm concentration

Postby TIAN WANTING » Sat Nov 09, 2019 9:33 am

and maybe this is a right file of datebased
Attachments
db.zip
(238.84 KiB) Downloaded 4 times

Tim
Posts: 836
Joined: Mon May 15, 2017 3:46 pm

Re: question about pm concentration

Postby Tim » Sun Nov 10, 2019 12:29 pm

Hi,

The differences are that small because you added a huge a mount of background concentration and only small amounts of additional PM are added to this large background concentration.

Best regards,
Tim

TIAN WANTING
Posts: 16
Joined: Mon Sep 30, 2019 4:55 am

Re: question about pm concentration

Postby TIAN WANTING » Wed Nov 13, 2019 5:40 am

Hi, Tim

Thanks for your help and the results of pm concentration are difference.
But there are some other problems in my simulation :cry:
Did as you say I make the emission rate bigger and it works.
I set up simulation for 24 hours but error occurred at 8:00am,
it said "Terminating thread 16564 ** ** Thread raised exception: [EOverflow] Floating point overflow "
Then I checked the full forcing file and make wind speed smaller.
but is not work and even worse that error occurred before the simulation.(like the photo)
Could you help me to solve it...i uploaded my folder... :oops: :cry:
Look forward to your reply, Thank you

Best Regards
Tian
Attachments
Tian.zip
(1.49 MiB) Downloaded 1 time
floating.png

Tim
Posts: 836
Joined: Mon May 15, 2017 3:46 pm

Re: question about pm concentration

Postby Tim » Wed Nov 13, 2019 10:49 am

Hi,

You have a very high resolution and thus only 5 m space from buildings to the model border. That's why the error says that you need to increase the grids at the border or choose a coarser resolution to avoid those turbulences.

Best regards,
Tim

TIAN WANTING
Posts: 16
Joined: Mon Sep 30, 2019 4:55 am

Re: question about pm concentration

Postby TIAN WANTING » Wed Nov 13, 2019 11:09 am

Hi, Tim

Very happy to get your answer ^^
if i want to increase the grids at the border how can i increase the grids at right and bottom part?(yellow part in the photo)
should i make space again?
Looking forward to your reply

Best regards
Tian
Attachments
2019-11-13 오후 7-57-20.png

Tim
Posts: 836
Joined: Mon May 15, 2017 3:46 pm

Re: question about pm concentration

Postby Tim » Wed Nov 13, 2019 11:12 am

Hi Tian,

Go into the Tools tab and try the tool "Add empty cells at border ...". Since the problem occurs at the top right of your model area, I would also recommend to add grid cells at that side. You should add them on every border.

Best regards,
Tim

TIAN WANTING
Posts: 16
Joined: Mon Sep 30, 2019 4:55 am

Re: question about pm concentration

Postby TIAN WANTING » Wed Nov 13, 2019 11:16 am

Hi, Tim

Thank your very much i will try add the grids and run simulation again :)

Best regards
Tian


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