vortex center in idealized vortex following simulation

[ltt]

Hi colleagues,
I am running an idealized vortex following simulation using the settings below. In the rsl.error.0000 file (attached), the vortex center is declared every 18 seconds, I have some following inquiries and would much appreciate your clarifications and instructions:
1. are the x, y positions defined for the inner-most domain (d03)?
2. how should I change time_step, and parent_time_step_ratio to get the center position every 30 minutes or every hour?
3. how to define the position of the vortex center in d01 and d02 as well?
Thank you!

&domains
time_step =54,
time_step_fract_num = 0,
time_step_fract_den = 1,
max_dom = 3,
s_we = 1, 1, 1,
e_we = 480, 481, 721,
s_sn = 1, 1, 1,
e_sn = 480, 481, 721,
s_vert = 1, 1, 1,
e_vert = 56, 56, 56,
dx = 9000, 3000, 1000,
dy = 9000, 3000, 1000,
ztop = 20000, 20000, 20000,
grid_id = 1, 2, 3,
parent_id = 0, 1, 2,
parent_grid_ratio = 1, 3, 3,
parent_time_step_ratio = 1, 3, 3,

 

[kwerner]

1. are the x, y positions defined for the inner-most domain (d03)?

I assume you're talking about the lines you can read in the rsl* files? If so, you can see the grid it refers to in the example line below (this is for grid 3, meaning grid 3 is the one that just moved).

Grid            3  New SW corner (in parent x and y):         121         121

2. how should I change time_step, and parent_time_step_ratio to get the center position every 30 minutes or every hour?

I'm not sure what you mean by "to get the center position." Can you clarify what exactly you're interested in obtaining?

3. how to define the position of the vortex center in d01 and d02 as well?

The vortex center is simply determined based on where the lowest pressure is found. Your inner nest will adjust to essentially center itself to follow the lowest pressure until it reaches the threshold within the edge of of its parent nest. At that point, the parent will move. Since I'm not able to see your full namelist, I can't see if you've set any of the below parameters, but these descriptions may be helpful.

Namelist variables for controlling the automatic moving nest:
                   Note that this moving nest option needs to be activated at the compile time by adding -DMOVE_NESTS
                   and -DVORTEX_CENTER to the ARCHFLAGS. This option uses a mid-level vortex following algorithm to
                   determine the nest move. This option is experimental.
 vortex_interval(max_dom)            = 15       ! how often the new vortex position is computed
 max_vortex_speed(max_dom)           = 40       ! used to compute the search radius for the new vortex position
 corral_dist(max_dom)                = 8        ! how many coarse grid cells the moving nest is allowed to get
                                                  near the mother domain boundary
 track_level                         = 50000    ! pressure value in Pa where the vortex is tracked
 time_to_move(max_dom)               = 0.       ! time (in minutes) to start the moving nests

 tile_sz_x                           = 0,       ! number of points in tile x direction
 tile_sz_y                           = 0,       ! number of points in tile y direction
                                                  can be determined automatically
 numtiles                            = 1,       ! number of tiles per patch (alternative to above two items)
 nproc_x                             = -1,      ! number of processors in x for decomposition
 nproc_y                             = -1,      ! number of processors in y for decomposition
                                                  -1: code will do automatic decomposition
                                                  >1: for both: will be used for decomposition

 

[ltt]

Hi Kwener, Thank you for your instructions, and my apologies for the delayed response as I was unable to return to this work until now.

Regarding my second question, I noticed that the vortex center can be extracted every minute, so the issue is resolved.

For my first question, I wanted to clarify whether the numbers below (obtained from [grep "vortex center" rsl.error.0000]) pertain to Grid 3.

2007-09-01_00:14:00 vortex center (in nest x and y): 363.3971 363.3405

2007-09-01_00:14:20 vortex center (in nest x and y): 363.3971 363.3405

2007-09-01_00:14:40 vortex center (in nest x and y): 363.3971 363.3405

2007-09-01_00:15:00 vortex center (in nest x and y): 365.4999 362.4999

2007-09-01_00:15:20 vortex center (in nest x and y): 362.4999 362.4999

2007-09-01_00:15:40 vortex center (in nest x and y): 362.4999 362.4999

If so, then why is the vortex center not precisely located at the center of Grid 3 (x=360, y=360)? As you mentioned, "the inner nest will adjust to essentially center itself to follow the lowest pressure", the vortex center should be situated at the center of Grid 3.

About the third question, I am curious about how we can define the (x,y) coordinates of the vortex center in Grid 2 and Grid 1.

I would greatly appreciate your feedback and guidance on these matters.

 

[kwerner]

Yes, the x,y coordinates you see in rsl.error.0000 pertain to grid3. I'm not sure why the center isn't exactly in the center of the domain, but if you are interested in the code for this, take a look in the share/mediation_nest_move.F file, which is how all the positioning is calculated for vortex-following.

You may be able to define the x,y coordinates of grids 2 and 3 by doing a calculation using the sizes of each domain, the parent_grid_ratio, and the movement information of the nested domain(s). You could also potentially add some code into the share/mediation_nest_move.F file to print out the information for d01 and d02.

 

[ltt]

Thank you, Kwerner, for the information. I will review the share/mediation_nest_move.F file and let you know if I have any further questions. I appreciate your guidance.