Documentation of the Evaluation of CALPUFF and Other Long ...

In STEP 1, an initial first guess wind field is modified through parameterized diagnostic wind
field effects due to terrain: blocking and deflection, channeling and slope flows. The first guess
wind field can be provided using prognostic meteorological model output (e.g., MM5) or
interpolated from observations. The resultant STEP 1 wind field is then modified in STEP 2 by
incorporating (blending) surface and upper‐air wind observations with the STEP 1 wind field in
an Objective Analysis (OA) procedure. CALMET has numerous options on how to generate the
STEP 1 wind field as well as how the STEP 2 OA procedure is performed. A series of CALMET
sensitivity tests were performed to examine the efficacy of OA, optimal radii of influence for
CALMET OA operations, and also to examine the role of horizontal grid resolution on
performance of both the diagnostic meteorological model and the performance of the CALPUFF
(Scire, 2000b) LRT dispersion model. CALMET was operated at three horizontal grid resolutions
(18, 12 and 4 km) with input prognostic meteorological data at horizontal resolutions of 80 km
(MM5 EXP1C), 36 km (MM5 EXP2H), and 12 km (MM5 EXP2H). Additionally, the Mesoscale
Model Interface (MMIF) tool (Emery and Brashers, 2009) was also applied using MM5 output at
80 km (MM5 EXP1C), 36 km (MM5 EXP2H), and 12 km (MM5 EXP2H) for CTEX5. Since no 80 km
MM5 data was available for CTEX3, MMIF was only used using the 36 and 12 km MM5 output
for CTEX3. In addition, for CTEX5 MMIF was run using 4 km MM5 output that was generated in
a “nest down” simulation from the 12 km MM5 simulation.
33 separate CALMET sensitivity tests were performed using MM5 output from the MM5
sensitivity simulations listed in Table 5‐1 and the CALMET sensitivity test experimental
configuration design given in Tables 5‐4 and 5‐5. The definitions of the 33 CALMET sensitivity
tests are given in Table 5‐6. CALPUFF sensitivity simulations were performed using a subset of
the 33 CALMET sensitivity tests for the CTEX3 and CTEX5 tracer test field experiments. For both
the CTEX3 and CTEX5 modeling periods, the CALMET EXP2 sensitivity test series was not run
with CALPUFF, as well as the EXP1 series for CTEX5. The BASED CALPUFF simulation
encountered an error in execution and failed to finish for the CTEX3 modeling period. The
80KM_MMIF was also not run for CTEX3 because MMIF was not designed to use MM4 data.
For CTEX5, a 4 km MM5 nest down simulation was performed off of the MM5 EXP2H sensitivity
test (see Figure 5‐1) so that a 4KM_MMIF CALPUFF sensitivity test could also be performed.
Table 5‐4. CALMET sensitivity test experiment configuration for grid resolution.
Experiment
CALMET
Resolution
(km)
MM5
Resolution
(km)
BASE 18 80
EXP1 12 80
EXP2 4 80
EXP3 12 36
EXP4 12 12
EXP5 4 36
EXP6 4 12
Table 5‐5. CALMET Objective Analysis (OA) sensitivity test configurations.
Experiment RMAX1 RMAX2
Series
(km) (km) NOOBS Comment
A 500 1000 0 Use surface and upper‐air met obs
B 100 200 0 Use surface and upper‐air met obs
C 10 100 0 Use surface and upper‐air met obs
D 0 0 2 Don’t use surface and upper‐air met obs
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