air quality assessment & management
Reference and User Manual
AirWare   On-line Reference Manual
  Release Level 6.2
  Release Date 2013 09
  Revision Level 1.0
Last modified on:   Friday, 15-Nov-13 21:05 CET

Model Domain Object

All simulation model runs or scernarios are implemented for a certain area of interest, location and extent, or model domain. ALso, from the master emission inventory, domain specific inventories can be generated.

Domains are OBJECTS that can be selected from the OBJECT DATA BASE hierarchical selection/navigator tools.

A domain usually will cover a specific area of interest such as a city, industrial district, part of the transportation system, the area around a major emission source like a thermal power station or major industry, or the entire region of an application. The domain definition provides a shared data structure to ensure the consistency between

  1. all the georeferenced data such as the emission sources,
  2. a meteorological scenario,
  3. model grid and sub-grids and thus georeferenced output,
  4. results post-processing such as exposure analysis.

A Domain is a named object with the standard object MEATA DATA header.

Due its multiple use by different models, scenarios, and also as embedded grid in CAMx, domains are READ ONLY and can only be modified by ADMIN group user. The attributes of a domain include:

  1. Object META DATA including name and description;
  2. Symbolic georeference (data driven set of administrative or geographical concepts such as region, province, community)
  3. Location and (rectangular) extent, defined by:
    • Reference point X and Y (in the center of the domain) used to locate the domain; this is shown as the usual default OBJECT location indicator as a circle on the map, it can edited by ADMIN users, also used to locate the object on the map interactively;
    • Origin X and Y: map coordinates of the origin (lower left corner) of the domain, computed from reference and extent, read only;
    • Aspect ratio (symbolic selection between square 1:1 and landscape 4:3);
    • East-West extent or width in km
    • North-South extent in km (computed, read only)
    • area covered (in km², computed, read only)
    • the upper right corner is computed and stored/accessible in the data base, but not displayed.
    • Map margin (in % of the domain extent, generates a margin around the domain rectangle).
  4. Background map: MAP ID for the background map (hidden), the map can be selected interactively through the MapCatalog.
The Domain is described by these attributes in tabular format together with the background map indicating the extent with the rectangular domain boundaries drawn on the background map.

For a new domain, the ADMIN user can specify:

  • name and description;
  • select the aspect ratio and horizontal extent;
  • select the map window size in % of the domain width;
  • define the location of the reference point i(center of the domain);
  • select an alternative background map from the MapCatalog;

Nested grid constraints

CAMx uses a nested grid scheme to calculate results for sub-domain at a higher resolution. To make that possible, a number of constrainst apply for domain that are to be used as sub-domains with CAMx. See also: Configuration of Scheduled Scenarios.
  1. The domain must be square;
  2. The corner point must be positioned on a 3km master grid node;
  3. The domain size (extent) must be modulo 3.
  4. The extent must not exceed 24 km.

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