The Layalloc program calculates 3-D emissions from a 2-D SMOKE emissions file. Layalloc is used to reallocate single layer 2-D surface layer emissions into multiple model layers. This approach is useful for processing pre-gridded or industrial area source inventories that do not contain stack information for plume rise treatment but represent elevated sources.

Layalloc reads in a gridded 2-D SMOKE emissions file (output from the Smkmerge program) and redistributes the emissions into multiple model layers based on a user-defined vertical profile. The vertical profiles that are input to Layalloc consist of a layer bottom height, layer top height, and percentage of emissions to allocate to the layer. SMOKE willl interpolate from the layer heights (in meters) to the model layers (in sigma-pressure). This approach assumes that the vertical factors are uniformly applied over all horizontal grid cells. The resulting hourly, gridded, speciated 3-D emissions data are output to a new I/O API file with the same temporal resolution and the same model species as the original 2-D emissions file.