The intensity of tropical cyclone

General scientific issues regarding ROMS

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manhnt181
Posts: 33
Joined: Wed Feb 03, 2021 5:07 pm
Location: Institute of Geophysics

The intensity of tropical cyclone

#1 Unread post by manhnt181 »

Hello everyone,
I've been practicing COAWST model to simulate the intensity of the tropical cyclones in the southeast Asian. In my experiment, I had set up three cases, including WRF-control, WRF-update SST, COAWST (WRF+ROMS+SWAN) to run the 48-h simulation. The result showed that the intensity of TC in COAWST model is moderately weaker than that of WRF and WRF with SST update option. Besides, the SST value in the COAWST model is lowest among 3 cases. Some of my results are displayed in the below. Fig2 is COAWST, fig3 is WRF-update SST and fig 4 is WRF-control.
Can anyone give me some advices to improve the simulation process of COAWST mode?
Any suggestions will be highly appreciated!
Thanks all,
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sst_21Z03NOV2017.png
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jcwarner
Posts: 1172
Joined: Wed Dec 31, 2003 6:16 pm
Location: USGS, USA

Re: The intensity of tropical cyclone

#2 Unread post by jcwarner »

What did the SST for ROMS look like before the TC crossed into the domain, and compare that to the SST from the WRF control.
How did you set the initial vertical stratification for ROMS?
-j

manhnt181
Posts: 33
Joined: Wed Feb 03, 2021 5:07 pm
Location: Institute of Geophysics

Re: The intensity of tropical cyclone

#3 Unread post by manhnt181 »

Hi Dr. Warner,
Thank you for your reply.
Regarding to the initial vertical stratification for ROMS, I set up like that:
mini_depth=10m,
theta_s=10;
theta_b=0.4;
Tcline=50;
N=30;
Vtransform =1;
Vstretching =1;
Additionally, the initial condition of SST in three cases (WRF-CTL, WRF-UDSST, COAWST) are displayed respectively in the below (fig 2->fig4) and they are compared with the SST analysis data (fig1) at the same time.
If the above information is not enough to make any suggestions to improve the result of the simulation process, please let me know.
Thank you for your help!
Attachments
sst_12Z02nov2017.png
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sst_12Z02NOV2017.png
sst_12Z02NOV2017.png (120.15 KiB) Viewed 3774 times

jcwarner
Posts: 1172
Joined: Wed Dec 31, 2003 6:16 pm
Location: USGS, USA

Re: The intensity of tropical cyclone

#4 Unread post by jcwarner »

i guess i was not really clear in my suggestion, sorry.
The plots you just posted show the initial conditions for the TC centered at 12Z02Nov2017.
What do the initial conditions look like west of that region, where the TC will make landfall?
The WRF CTL SST looks warmer than the WRF-sstupdate and the ROMS initial conditions, so if ROMS is starting out cooler then it will produce a weaker TC.
Also, you need to look at the vertical structure of the temperature field. The WRF control probably does not change SST, so it will stay strong.
The WRF SSTupdate will get a new SST from a netcdf file, that is from satellite data (?).
The simulation with ROMS will include vertical mixing and advection in the ocean. Suggest you look at the mixing, the vertical structure of the temperature in the model, and thickness of the top grid cell, etc.

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