Structure & Conventions

In order to interpret detailed results from the BETR Global model, or to read and modify the model code, it is necessary to understand the naming conventions used in the model.

BETR Global describes the global environment as a set of multimedia regions on a 15^o x 15^o grid. Individual model regions are identified by their numerical index according to the map below.. (Click to enlarge it and for easy printing!):

Within each region, the environment is described as a set of seven connected bulk compartments. The numerical indexes for these bulk compartments are:

Since there are 288 regions in the model, and each region can contain up to 7 bulk compartments, there are (288 x 7) = 2016 possible compartments. Some of these compartments actually have zero volume (for example, there is no coastal water compartment in Region 91, which includes inner Mongolia). But, individual bulk compartments are sometimes referred to using a "compartment index" in which they are numbered from 1 to 2016, starting with Upper Air in Region 1 (compartment index = 1), and ending with Sediment in Region 288 (compartment index = 2016).