A comparison of plume rise algorithms to stack plume measurements in the Athabasca oil sands
<p>Plume rise parameterizations calculate the rise of pollutant plumes due to effluent buoyancy and exit momentum. Some form of these parameterizations is used by most air quality models. In this paper, the performance of the commonly used Briggs plume rise algorithm was extensively evaluat...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-10-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/18/14695/2018/acp-18-14695-2018.pdf |
| Summary: | <p>Plume rise parameterizations calculate the rise of pollutant plumes due to
effluent buoyancy and exit momentum. Some form of these parameterizations is
used by most air quality models. In this paper, the performance of the
commonly used Briggs plume rise algorithm was extensively evaluated, through
a comparison of the algorithm's results when driven by meteorological
observations with direct observations of plume heights in the Athabasca oil
sands region. The observations were carried out as part of the Canada-Alberta
Joint Oil Sands Monitoring Plan in August and September of 2013. Wind and
temperature data used to drive the algorithm were measured in the region of
emissions from various platforms, including two meteorological towers, a
radio-acoustic profiler, and a research aircraft. Other meteorological
variables used to drive the algorithm include friction velocity,
boundary-layer height, and the Obukhov length. Stack emissions and flow
parameter information reported by continuous emissions monitoring systems
(CEMSs) were used to drive the plume rise algorithm. The calculated plume
heights were then compared to interpolated aircraft SO<sub>2</sub> measurements,
in order to evaluate the algorithm's prediction for plume rise. We
demonstrate that the Briggs algorithm, when driven by ambient observations,
significantly underestimated plume rise for these sources, with more than
50 % of the predicted plume heights falling below half the observed
values from this analysis. With the inclusion of the effects of effluent
momentum, the choice of different forms of parameterizations, and the use of
different stability classification systems, this essential finding remains
unchanged. In all cases, approximately 50 % or more of the predicted
plume heights fall below half the observed values. These results are in
contrast to numerous plume rise measurement studies published between 1968
and 1993. We note that the observations used to drive the algorithms imply
the potential presence of significant spatial heterogeneity in meteorological
conditions; we examine the potential impact of this heterogeneity in our
companion paper (Akingunola et al., 2018). It is suggested that further study
using long-term in situ measurements with currently available technologies is
warranted to investigate this discrepancy, and that wherever possible,
meteorological input variables are observed in the immediate vicinity
of the emitting stacks.</p> |
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| ISSN: | 1680-7316 1680-7324 |