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

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• <strong>CALPUFF</strong> 100 km (all dispersion options) <strong>and</strong> 600 km PG dispersion simulations, <strong>CALPUFF</strong><br />

was set‐up to not allow for partial plume penetration <strong>of</strong> inversion layer (MPARTL = 0). The<br />

IWAQM Phase II (1998) guidance recommends MPARTL = 1.<br />

• <strong>CALPUFF</strong> 600 km AERMOD <strong>and</strong> <strong>CALPUFF</strong> turbulence dispersion simulations, <strong>CALPUFF</strong> was<br />

set‐up to use <strong>the</strong> Probability Density Function (PDF) option for convective dispersion<br />

(MPDF = 1). The IWAQM Phase II guidance does not recommend using PDF for convective<br />

dispersion.<br />

• <strong>CALPUFF</strong> 600 km simulations <strong>and</strong> 100 km <strong>CALPUFF</strong>/MMIF simulations use minimum <strong>and</strong><br />

maximum mixing height values <strong>of</strong> 0 m <strong>and</strong> 6000 m, respectively. The <strong>CALPUFF</strong> 100 km<br />

BASE case <strong>and</strong> sensitivity simulations use minimum <strong>and</strong> maximum mixing height values <strong>of</strong><br />

20 m <strong>and</strong> 3300 m, respectively. The 1998 IWAQM Phase II guidance recommends <strong>the</strong><br />

minimum <strong>and</strong> maximum mixing heights be set equal to 50 m <strong>and</strong> 3000 m, respectively.<br />

• The <strong>CALPUFF</strong> 100 km BASE case <strong>and</strong> sensitivity simulations use a maximum slug length <strong>of</strong><br />

0.1 CALMET grid units (XMXLEN = 0.1), whereas <strong>the</strong> 100 km <strong>CALPUFF</strong>/MMIF simulations<br />

used a maximum length <strong>of</strong> 1.0 CALMET grid units. The IWAQM Phase II guidance<br />

recommends XMXLEN = 1.<br />

• The <strong>CALPUFF</strong> 100 km BASE case <strong>and</strong> sensitivity simulations use a maximum slug/puff<br />

travel distance <strong>of</strong> 0.1 grid units per sampling period (XSAMLEN = 0.1), whereas <strong>the</strong> 100 km<br />

<strong>CALPUFF</strong>/MMIF simulations used a maximum travel distance <strong>of</strong> 1.0 grid units. The<br />

IWAQM Phase II guidance recommends XSAMLEN = 1.<br />

• The <strong>CALPUFF</strong> 100 km BASE case <strong>and</strong> sensitivity simulations use a maximum <strong>of</strong> 199<br />

slugs/puffs released from one source per sampling step (MXNEW = 199), whereas <strong>the</strong> 100<br />

km <strong>CALPUFF</strong>/MMIF simulations used a maximum <strong>of</strong> 99 new slugs/puffs. The IWAQM<br />

Phase II guidance recommends MXNEW = 99.<br />

• The <strong>CALPUFF</strong> 100 km BASE case <strong>and</strong> sensitivity simulations use a maximum <strong>of</strong> 5 sampling<br />

steps per slug/puff during one time step (MXSAM = 5), whereas <strong>the</strong> 100 km<br />

<strong>CALPUFF</strong>/MMIF simulations used a maximum <strong>of</strong> 99 sampling steps per slug/puff. The<br />

IWAQM Phase II guidance recommends MXSAM = 99.<br />

• The <strong>CALPUFF</strong> 100 km BASE case <strong>and</strong> sensitivity simulations use a minimum sigma‐y <strong>and</strong><br />

sigma‐z value <strong>of</strong> 0.01 m per new slug/puff (SYMIN = 0.01 <strong>and</strong> SZMIN = 0.01), whereas <strong>the</strong><br />

100 m <strong>CALPUFF</strong>/MMIF simulations used a minimum sigma‐y <strong>and</strong> sigma‐z value <strong>of</strong> 1 m per<br />

new slug/puff. The IWAQM Phase II guidance recommends SYMIN = 1 <strong>and</strong> SZMIN = 1.<br />

• The <strong>CALPUFF</strong> 100 km BASE case <strong>and</strong> sensitivity simulations use a minimum wind speed <strong>of</strong><br />

1 m/s for non‐calm conditions (WSCALM = 1), whereas <strong>the</strong> 100 km <strong>CALPUFF</strong>/MMIF<br />

simulations used a minimum wind speed <strong>of</strong> 0.5 m/s. The IWAQM Phase II guidance<br />

recommends WSCALM = 0.5.<br />

We noted that <strong>the</strong> date on <strong>the</strong> CALMET input control file for <strong>the</strong> BASEA sensitivity test was later<br />

than <strong>the</strong> date on <strong>the</strong> CALMET output file for BASEA. We reran <strong>the</strong> BASEA CALMET <strong>and</strong> <strong>CALPUFF</strong><br />

sensitivity tests <strong>and</strong> got slightly different results.<br />

3.4 GP80 MODEL PERFORMANCE EVALUATION<br />

Previous studies evaluated <strong>CALPUFF</strong> using <strong>the</strong> GP80 tracer experiment data using <strong>the</strong> Irwin<br />

plume fitting evaluation approach (EPA, 1998a). Thus, <strong>the</strong> same approach was adopted in this<br />

study so we could compare <strong>the</strong> performance <strong>of</strong> <strong>the</strong> newer version <strong>of</strong> <strong>CALPUFF</strong> with past<br />

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