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Table of Contents - The Atmospheric Studies Group at TRC

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Section 9: CALPUFF<br />

9.6 Volume Source Emissions File (VOLEMARB.DAT) with Arbitrarily Varying Emissions<br />

<strong>The</strong> VOLEMARB.DAT file contains volume source d<strong>at</strong>a for sources with detailed, arbitrarily varying<br />

characteristics in time. Such volume sources may have time-varying emission r<strong>at</strong>es, time-varying initial<br />

size, and time-varying loc<strong>at</strong>ion (they may move).<br />

VOLEMARB.DAT is a free-form<strong>at</strong>ted ASCII d<strong>at</strong>a file (see <strong>Table</strong> 9-28 for an example). Multiple files<br />

may be provided if groups <strong>of</strong> sources possess very different time-variability. For example, group 1 may<br />

require hourly d<strong>at</strong>a records for the entire simul<strong>at</strong>ion period, while group 2 may produce emissions for<br />

only a few weeks during the simul<strong>at</strong>ion. Using a second file for group 2 is more economical to prepare<br />

because a single d<strong>at</strong>a record can be used to prescribe a long period with no (or constant) emissions. Each<br />

such file must cover the entire modeling period, no source may appear in more than one file, and the<br />

species list must be identical among these files.<br />

D<strong>at</strong>a in the VOLEMARB.DAT file are independent <strong>of</strong> the horizontal and vertical grid systems being used<br />

in the model. <strong>The</strong> horizontal coordin<strong>at</strong>es are specified for a particular map projection and d<strong>at</strong>um, and<br />

CALPUFF converts these coordin<strong>at</strong>es to the map projection and d<strong>at</strong>um used in the modeling grid.<br />

<strong>The</strong> header records <strong>of</strong> the VOLEMARB.DAT file (see <strong>Table</strong> 9-29) contain the number <strong>of</strong> sources,<br />

starting and ending time periods <strong>of</strong> d<strong>at</strong>a in the file, time zone, map projection and d<strong>at</strong>um, and a list <strong>of</strong> the<br />

emitted species. When more than one file is used, the species inform<strong>at</strong>ion in each file must be the same.<br />

<strong>The</strong> number <strong>of</strong> sources NSRC must identify the number <strong>of</strong> sources in the file, and the sum <strong>of</strong> the NSRC<br />

values from all files must equal the total number <strong>of</strong> sources (NVL2) provided in Subgroup (16a) <strong>of</strong> the<br />

control file. A set <strong>of</strong> time-invariant records (see <strong>Table</strong> 9-30) are read after the header records. <strong>The</strong>se<br />

records specify the source names, and a user-defined index (read but not used). A set <strong>of</strong> time-varying<br />

d<strong>at</strong>a follows (see <strong>Table</strong> 9-31). <strong>The</strong> time-varying records contain the source loc<strong>at</strong>ion, its effective height<br />

above ground, the elev<strong>at</strong>ion (MSL) <strong>at</strong> the loc<strong>at</strong>ion, the initial σ y and σ z , and the emission r<strong>at</strong>e for each<br />

species.<br />

9-188

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