Post on 01-Jan-2016
transcript
TemplateTemplate
Evaluation of an Advanced Reactive Puff Model using
Aircraft-based PlumeMeasurements
Krish Vijayaraghavan, Prakash Karamchandani, Bart Brashers, Shu-Yun Chen, Greg Yarwood, Sue
Kemball-CookENVIRON International Corporation, Novato, CA
Biswanath Chowdhury - Sage Management, Princeton, NJ
Eladio Knipping - EPRI, Washington, DC
9th Annual CMAS Conference, October 11-13, 2010
Chapel Hill, North Carolina
2
Outline
• Model Description
• Objective
• Model Inputs and Application
• Aircraft Traverses and Model Receptors
• Performance Evaluation
• Conclusions and Recommendations
Model Description - SCICHEM
• Second-order Closure Integrated Puff model with Chemistry
• Three dimensional Lagrangian puff model• Plume is represented as a superposition of a series
of 3-D Gaussian puffs• Uses second-order turbulence closure• Dynamic plume-rise calculation based on
conservation of energy and momentum• Puff-splitting algorithm allows accurate treatment of
wind shear• Puff merging minimizes number of puffs• Efficient adaptive time-step algorithm
Model Description - SCICHEM
• Detailed gas-phase photochemistry based on CB-IV• RADM aqueous-phase chemistry scheme• Inorganic aerosol thermodynamics (ISORROPIA)• Secondary Organic Aerosols (SOA) treatment• Sectional PM size distribution with two sections• Optional modal PM size distribution• SCICHEM can use either routine observations of
meteorology and concentrations or modeled 3-D fields.
Objective• Evaluate SCICHEM using aircraft observations of the plume from
the Dolet Hills power plant in NW Louisiana conducted during the Northeast Texas Air Care (NETAC) 2005 Air Quality Study
Source: Baylor University Report
Model Inputs and Application• Simulation performed for 8 September 2005• Hourly emissions of SO2 and NOx from CAMD • Surface and upper-air meteorology from Shreveport, from
NOAA Integrated Surface Hourly Observations DVD (ds3505) and the NOAA ESRL radiosonde database
• Fixed wind direction to best match observed plume direction• Constant background chemical environment specified using
domain-averages from previous CAMx simulations as well as aircraft data
• Stack parameters for Dolet Hills Power Plant (in NW Louisiana near the Texas border)– Height = 160 m– Diameter = 7.6 m– Exit Temperature = 70 C– Exit Velocity = 26 m/s
16
SCICHEM Evaluation in a Prior Application
Source: Karamchandani et al. 2000. Environ. Sci. Technol., 34, 870-880.
Comparison with helicoptermeasurements of Cumberland
power plant plume
17
Conclusions and Recommendations
• Aircraft observations of plumes provide another dimension to evaluating air quality models
• SCICHEM was evaluated using aircraft measurements of a power plant plume along the Louisiana/Texas border
• Model performance statistics are good near the stack and generally reasonable farther away.
• Model application used readily available data
• Need to investigate the effects of meteorology and background pollutant concentrations on predicted peak concentrations: can model performance be improved by using 3-D meteorology and concentration fields?