CESM2 Tutorial

• Start running a case in CESM2
• Case study: modifying sea surface temperature (SST) in a land-atmospheric coupled case

Step 1. Connect to Taiyi Supercomputer

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Process 1. Download MobaXterm for Windows

Download link: https://mobaxterm.mobatek.net/download.html

Process 2. Open MobaXterm and start a new session

“User sessions” (right click) -> “New session”

In Session settings:

• Click SSH
• Remote host: 172.18.6.175 (172.18.6.178)
• Specify username: ese-liangll

• Press OK
• Copy and Paste password (You won’t see the password on the screen)

• Press either Yes/No

Note: If you failed at this step, please delete this session and start from Step. 2 to create a new session.

If you see it as below, congrats, you have successfully connect to Taiyi supercomputer!

For more information on Taiyi, please refer to hpc.sustech.edu.cn
LINK: https://hpc.sustech.edu.cn/process/user_guide.html

Step 2. Let’s run CESM2

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Porcess 1. Creat a case

• [ese-liangll@login02 ~]$ cd /work/ese-liangll/CESM2.1.3/my_cesm_sandbox/cime/scripts/

• [ese-liangll@login02 scripts]$ ./create_newcase –case /data/ese-liangll/CESM2.1.3/cases/newtest_TA –compset FHIST_BGC –res f09_f09_mg17 –mach sustechliangll

Note: you need to rename your folder such as “newtest_xxx” (do not have any blank space in your folder name)

Process 2. Case setup

• [ese-liangll@login02 scripts]$ cd /data/ese-liangll/CESM2.1.3/cases/newtest_TA/

Change run options: do monthly run for 12 months

• [ese-liangll@login02 newtest_TA]$ ./xmlchange STOP_OPTION=nmonths,STOP_N=12

Change computation requirement: total tasks = 240 cores

• [ese-liangll@login02 newtest_TA]$ ./xmlchange NTASKS=240

Check the running requirements

• [ese-liangll@login02 newtest_TA]$ ./preview_run

• [ese-liangll@login02 newtest_TA]$ ./case.setup

Process 3. Case build

• [ese-liangll@login02 newtest_TA]$ ./case.build

Process 4. Case run

Note: make sure to read taiyi user manual and attend training as a beginner.
Manual: https://hpc.sustech.edu.cn/ref/taiyi_User_Manual_v0.6.pdf

Do preview run to check the requirement to run the case.

• [ese-liangll@login02 newtest_TA]$ ./preview_run

• [ese-liangll@login02 newtest_TA]$ vi run_newtest_TA.sh

Type the following statements. Note: you may need to change the case name with your own.

bsub -J newtest_TA -q medium -n 240 -R “span[ptile=40]” -W 12:00 -o stdout_%J.out -e stderr_%J.err ./case.submit

• [ese-liangll@login02 newtest_TA]$ chmod 740 run_newtest_TA.sh

• [ese-liangll@login02 newtest_TA]$ ./run_newtest_TA.sh

Now you have submit the job and CESM2 should be running after waiting in the queue.

Note: Check the queue using bqueues

• [ese-liangll@login02 newtest_TA]$ bqueues

Note: Check the queue using bqueues

• [ese-liangll@login02 newtest_TA]$ bjobs

Additional information

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CESM model structure on Taiyi

Additional information on CESM2

• Model Official Website: https://www.cesm.ucar.edu/models/cesm2
• Quick Start: https://escomp.github.io/CESM/versions/cesm2.1/html/
• Component set: https://www2.cesm.ucar.edu/models/cesm2/config/2.1.3/compsets.html
• Debug platform DiscussCESM: https://bb.cgd.ucar.edu/cesm/

Model infrastructure and technical notes

• Land component CLM5.0: https://escomp.github.io/ctsm-docs/versions/release-clm5.0/html/tech_note/Introduction/CLM50_Tech_Note_Introduction.html
• Atmosphere component CAM6.0: https://ncar.github.io/CAM/doc/build/html/index.html

Contact info.: liangsj2021@mail.sustech.edu.cn