Release Level	6.0
	Release Date	2011 10
	Revision Level	1.0

Last modified on:   Tuesday, 29-Nov-11 12:08 CET

CAMx sub-domains: CAMx

1. The largest domain is the "main domain", smaller domains inside the main domain are called "subdomains".
2. Each subdomain has to cover at least on grid cell of the master domain. Therefore the size as well as the position of each subdomain depends on the grid definition of the master domain. For example, if master domain has a resolution of 30km, the smallest subdomain possible has a size of 30km and it has to be positioned exactly on the grid of the master domain, compare figure.
3. Subdomains may not overlap.
4. A subdomain may be located within another subdomain. The current implementation allows 4 levels of domains, but this could be extended in principle.
5. When subdomains are nested, the larger subdomain has to be selected first.
6. The maximum number of subdomains is 9.
7. There are further restrictions to resolutions (compare below), but Airware's CAMx domain selection offers only 'allowed' resolutions.

The following error messages will displayed on selecting a subdomain which violates one of the above rules:

Violation of point 2:	Subdomain 'name' is not compatible to grid of main domain
Violation of point 3:	Subdomain 'name1' overlaps with 'name2'
Violation of point 5:	Subdomain 'name1' is inside domain 'name2'. Larger domain needs to be selected first
Violation of point 6:	Too many subdomains. Maximum number of subdomains is 9
Violation of point 7:	in case there no 'allowed' resolution for the subdomain: "No compatible resolution for subdomain 'name".

Excerpt of CAMx User Guide, p.2-4 ff:

Each grid nest is defined over a subset of master (coarsest) grid cells. The range of master grid row and column indices that define the coverage of each nested grid must be specified in the run control file. An integer number of nested grid cells must span one master grid cell; this number is referred to as a “meshing factor”.

1. The ratio of master grid cell size to nested grid cell size must be an integer (e.g., a “meshing factor” of 3 means that 3 nested cells span the distance of 1 master cell, resulting in an area of 9 nested cells per master cell);
2. For telescoping grids (a nested grid containing an even finer grid), the cell size of the finest grid must be a common denominator for all parent grids above it (e.g., a 36-12-4 km or 36-12-2 km arrangement is allowed, but a 36-12-9 km is not);
3. The restriction in (2) above does not apply to parallel nested grids of the same generation (e.g., 4 km and 5 km grids can be located in different areas of a master grid provided that the master cell size is some multiple of 20 km);
4. Nested grids cannot overlap, although they may share a common boundary or edge;
5. Nested grids cannot extend into a boundary, or non-modeled, area of the master grid;
6. CAMx is currently configured to allow four "generations" of nests (e.g., four levels of telescoping grids); this can be extended in the code easily if more than four levels of nests are required;