Data Assimilation Facility¶
This new feature to the code allows the user to specify winds that vary in x, y, z, and time! This page describes the methods users will need to follow to setup cases using variable winds.
Creating a Wind File¶
Although the naming of the wind file (background.wind) has not changed, the
new style is a binary file with a formatted header. Please note that this must
be written explicitly to be read by the main code and is sensitive to syntax. To
assist users with this aspect, a new program convert_wind accompanies this update.
While originally designed to convert original 1D wind files for testing
purposes, all the header format options have been included. In addition, this program
illustrates how the binary data is written, namely single-precision binary in order -
(Nx,Ny,Nz,n_var,Nt) where n_var = 3 (u,v,T). Note, pressure field can also
be appended but it must satisfy the hydrostatic balance so it is usually generated
internally.
Climatology¶
A climatology data base is available for users BUT should only be used for preliminary analysis or profile approximation due to its limitations. The data set contains zonal winds and temperature at 1 degree lines of latitude. It encompasses [-80:80] degrees with an approximate altitude range of [0:120] km.
To generate CIRA profiles build and run the program climatology.
New Input Options¶
| i_read_w: | 2-read 4D, 1-read 1D, 0-generate internally |
|---|---|
| dt_ramp: | Time between ramping segments (Recommended = dt0) |
| t_adjust_wind: | Time to start data time variation (Use: ramping with fixed winds) |
| n_skip_b: | Skip factor for background output (Testing) |
Note input options for boundary conditions, diffusion, hydrostatic balance, and ramping function (hyperbolic tangent) are strict for terrain cases.
Grid File¶
Grid type is restricted for ALL cases to i_grid=3 (full background array)!
Any grid file in the format of terrain_mesh will continue to work, however
it is recommended that users add the new header option to ensure consistency
between the domain and background fields. This is simply added in terrain_mesh.inp:
| i_header: | 1-write header, 0-no header (default) |
|---|