CMAQv5.0.2 PT3DDIAG bug fix
The PT3D diagnostic file is an optional output which can be created by setting an environment variable
setenv PT3DDIAG Y
This file shows how point source emissions are distributed vertically among model layers according to the plume rise algorithm. The emissions are summed over the synchronization steps within a given output time step. However, the normalization factor that was applied was the number of seconds, when it should have been the number of synchronization time steps.
In addition, the code determining when to write the output file has been modified, to ensure compatibility with the two-way WRF-CMAQ model.
Significance and Impact
The PT3D emissions output in the diagnostic file now correctly reflect what is in the model. Previously, values in the diagnostic file not only had the wrong magnitude, but the factor by which they were wrong depended on the number of synchronization steps during that output time step. Note that this bug was limited to the diagnostic file, and did not affect modeled concentrations at all.
Chris Nolte & David Wong, Atmospheric Modeling and Analysis Division, U.S. EPA