Long simulation time on some of the time-steps

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Chang_Shu
Posts: 29
Joined: Mon Jan 06, 2020 4:28 am

Long simulation time on some of the time-steps

Post by Chang_Shu » Tue Jul 13, 2021 6:09 pm

Hello, WRF team

I am running a 1km resolution WRF run with 3 nested domains for a future time frame.
I found that the simulation on some of the time-steps would take much longer time than most of the time-steps.
Please find an example snippet below I found from the rsl.* files:


Timing for main: time 2075-05-02_10:00:15 on domain 3: 0.04221 elapsed seconds
Timing for main: time 2075-05-02_10:00:15 on domain 2: 41.35098 elapsed seconds
Timing for main: time 2075-05-02_10:00:20 on domain 3: 0.03977 elapsed seconds
Timing for main: time 2075-05-02_10:00:25 on domain 3: 0.04215 elapsed seconds
Timing for main: time 2075-05-02_10:00:30 on domain 3: 0.03837 elapsed seconds
Timing for main: time 2075-05-02_10:00:30 on domain 2: 0.26364 elapsed seconds
Timing for main: time 2075-05-02_10:00:35 on domain 3: 0.03771 elapsed seconds
Timing for main: time 2075-05-02_10:00:40 on domain 3: 0.03286 elapsed seconds
Timing for main: time 2075-05-02_10:00:45 on domain 3: 0.04725 elapsed seconds
Timing for main: time 2075-05-02_10:00:45 on domain 2: 0.23428 elapsed seconds
Timing for main: time 2075-05-02_10:00:45 on domain 1: 57.36857 elapsed seconds
Timing for main: time 2075-05-02_10:00:50 on domain 3: 0.03843 elapsed seconds
Timing for main: time 2075-05-02_10:00:55 on domain 3: 0.04312 elapsed seconds
Timing for main: time 2075-05-02_10:01:00 on domain 3: 0.08528 elapsed seconds


This seriously slowed down my progress in the simulation.
Could you please let me know what would be the possible reason for this?

Thanks,

Chang

Ming Chen
Posts: 1656
Joined: Mon Apr 23, 2018 9:42 pm

Re: Long simulation time on some of the time-steps

Post by Ming Chen » Wed Jul 14, 2021 8:02 pm

Hi Chang,
radiation scheme usually takes quite a long time. Can you look at your namelist.input and see whether raft is set to 30?
WRF Help Desk

Chang_Shu
Posts: 29
Joined: Mon Jan 06, 2020 4:28 am

Re: Long simulation time on some of the time-steps

Post by Chang_Shu » Wed Jul 21, 2021 4:41 pm

Hi, Ming
I am using three nested domains with spatial resolutions of 9km, 3km and 1km
My settings of radiation in my namelist.input is :
mp_physics = 3, 3, 3
ra_lw_physics = 1, 1, 1
ra_sw_physics = 1, 1, 1
radt = 9, 3, 1
sf_sfclay_physics = 2, 2, 2

Would this be the problem?
Thanks,

Chang

Ming Chen
Posts: 1656
Joined: Mon Apr 23, 2018 9:42 pm

Re: Long simulation time on some of the time-steps

Post by Ming Chen » Fri Jul 23, 2021 9:33 pm

Chang,
I believe this issue is related to radiation. Can you try the option: radt = 9, 9, 9 and see whether the performance is better?
Please keep me updated. Thanks.
WRF Help Desk

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