Auto moving nest option

Discuss the nesting capability within the model itself and any problems you might have run into.

Auto moving nest option

Postby sunny963 » Tue Jul 22, 2008 11:29 am

My model have 3 domains, outer domain is 45km(121x121), middle domain is 15km(211x211), and inner domain is 5km(121x121) in the ARW version 2.2.1.
Among them, middle and inner domain is setted to automatic moving nest run.
In my model, the core of typhoon is always exist in the center of inner domain.
However, it was not in the middle domain.
The core of typhoon exist in the corner of middle domain after time, and finally the middle domain moves a little.
So the typhoon exist still in the coner of middle domain.
I want that typhoon exist center of domains not only inner domain but also middle domain.
So I modified 'corral_dist' option from 8(default) to 60 in the namelist.input
However the result was same.
How can I move the typhoon to the center of middle domain?
sunny963
 
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Joined: Tue Jul 22, 2008 10:30 am

Re: Auto moving nest option

Postby lgtq » Sat Aug 18, 2012 9:20 am

could anybody answer this questions?
my questions are same, how to apply a moving nest case to solve typhoon problems. i will appreciate if any books are recommended.
lgtq
 
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Joined: Sun Nov 16, 2008 4:44 am

Re: Auto moving nest option

Postby chaulamyu2014 » Mon May 14, 2018 12:48 pm

I also have the same problem, but finally got it fixed.
Did you modified the "corral_dist" for the inner-most nest? The corral_dist for the inner-most nest will control the movement of the middle nest when the innermost nest get too close to the middle nest. The following namelist is what I used for testing the movement of middle nest (you should see the middle nest (d02) most soon after the start of the simulation (wrfout time resolution is very small, i.e. 2 mins))

&time_control
history_interval = 60, 2, 2,
.......
.......
......

&domains
time_step = 45,
time_step_fract_num = 0,
time_step_fract_den = 1,
max_dom = 3,
s_we = 1, 1, 1,
e_we = 120, 151, 241,
s_sn = 1, 1, 1,
e_sn = 120, 151, 241,
s_vert = 1, 1, 1,
e_vert = 31, 31, 31,
dx = 27000, 9000, 3000,
dy = 27000, 9000, 3000,
ztop = 25000., 25000., 25000.,
grid_id = 1, 2, 3,
parent_id = 0, 1, 2,
i_parent_start = 1, 25, 66,
j_parent_start = 1, 25, 66,
parent_grid_ratio = 1, 3, 3,
parent_time_step_ratio = 1, 3, 3,
feedback = 1,
smooth_option = 0,
max_vortex_speed = 40, 40, 40,
corral_dist = 8, 8, 35,
time_to_move = 100000000, 0, 0,
track_level = 85000,


The most optimal value for corral_dist to make the storm always at the center of the middle always should takes the following formula:
corral_dist ~ ( e_we(middle) - e_we(innermost)/grid_ratio )/2

Hope this helps!

Chris Yu
chaulamyu2014
 
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Joined: Mon May 14, 2018 12:29 pm


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