Modeling, Source Attribution, and Data Broadcasting for BEE-TEX Eduardo (Jay) Olaguer, Ph.D. Program Director, Air Quality Science Houston Advanced Research Center
HARC Air Quality Model Neighborhood scale 3D dispersion model with its own chemical mechanism (47 gas phase reactions). Very high temporal (~ s) and horizontal (~0 m) resolution. (Note: SIP models for Houston have at best 4 km horizontal resolution.) Model can infer emissions from observed ambient concentrations (inverse mode) as well as to predict concentrations from emissions (forward mode). The inverse mode employs the adjoint method and 4D variational (4Dvar) data assimilation technique.
HARC Chemical Mechanism
Performance Evaluations of the HARC Model Model HO x radical predictions tested against 06 TRAMP data; comparison of HARC, CB05 and SAPRC O 3 predictions using OZIPR (Olaguer, 12a, J. Air & Waste Manage. Assoc., 62, 966-977). Simulated O 3 and NO x for two historical emission events in the Houston Ship Channel compared with observations from nearest downwind CAMS monitors (Olaguer, 12b, J. Air & Waste Manage. Assoc., 62, 978-988). Inverse model estimates of olefin/hcho event emissions based on in-situ monitoring data compared with SOF and DOAS remote sensing measurements during TexAQS II (Olaguer, 13, J. Geophys. Res.-Atmos., 118, 4936-4946).
Model Technical Advances GPU optimized/parallelized MATLAB code. HARC model will be used to optimize CAT reconstructions (Olaguer, 11, Atmos. Environ., 45, 6980-6986) for HAPS, both unreactive (e.g., benzene) and reactive (e.g., toluene and xylenes). Inverse modeling will also be performed based on CAT and Aerodyne mobile lab data, including for HCHO and 1,3-butadiene. QUIC model with NGA 3D building database will enhance model source attribution.
Computational Fluid Dynamics QUIC model used to simulate wind based on 3D LIDAR building morphology.
Meteorological Assumptions QUIC Model Input Roughness length Monin-Obukhov length ( height at which buoyant production of TKE equals wind shear production) Reference height Wind speed and direction at reference height Profile type (logarithmic, power law, etc.) Surface morphology (buildings, topography) HARC Model Input Surface temperature and lapse rate Relative humidity Mixing height Stability class (needed for vertical diffusivity) Horizontal diffusivity (can be optimized using data assimilation)
HCHO and SO 2 Source Attribution for a Texas Refinery Winds from QUIC model HARC model with chemistry (0 m, s resolution) run in inverse mode based on mobile lab measurements Emissions attributed primarily to fluidized cat cracking and desulfurization operations HCHO results agree with I-DOAS emission flux measurements for I- DOAS target area (~18 kg/hr) Inferred HCHO/SO 2 molar emission ratio agrees with ambient measurement data Olaguer, et al. (13), J. Geophys. Res.-Atmos., 118, 11,317 11,326.
Simulated (solid line), observed s (dashed line), and observed 5 min (dotted line) mixing ratios at 2 pm 3 pm LST (left) and 3 pm 4 pm LST (right) for HCHO (top) and SO 2 (bottom).
Concentration (micrograms/m 3 ) Concentration (micrograms/m 3 ) 900 800 700 U=2 m/s 1 0 900 800 700 Olaguer (11), Atmos. Environ., 45, 6980-6986 y (m) y (m) 600 0 400 300 0 900 800 700 600 0 400 300 0 Single point source 0 1 2 3-hr forward model results with true parameter values 0 300 400 0 600 700 800 900 x (m) 30 min assimilation window First Guess: E = 1 g/s K h =132 m 2 /s CAT-4Dvar reconstruction based on 2T90 Concentration (micrograms/m 3 ) 2 1 1 0 E = 10 g/s K h =13.2 m 2 /s Neutral stability Optimized: E = 9.3 g/s K h =16.2 m 2 /s y (m) y (m) 600 0 400 300 0 900 800 700 600 0 400 300 0 1 CAT reconstruction using ART and 2T90 DOAS configuration 0 300 400 0 600 700 800 900 x (m) 0 1 Error(micrograms/m 3 ) -5 - -15 Error of improved reconstruction -10 0-5 -30-10 -15-25 -5-0 -10-15 0-5 0 300 400 0 600 700 800 900 x (m) 0 300 400 0 600 700 800 900 x (m)
Hypothetical emission rate of 1 g/s of benzene
Hypothetical BEE-TEX Scenario True Concentration (micrograms/m 3 ) 1 Concentration (micrograms/m 3 ) 1 0 900 800 700 WS = 4 m/s WD = 1 0 900 800 700 y (m) 600 y (m) 600 0 400 300 0 40 80 60 1 140 160 180 0 2 240 260 280 300 0 300 400 0 600 700 800 900 0 1 x (m) 0 400 300 0 0 300 400 0 600 700 800 900 0 1 x (m) 40 60 80 1 140 160 180 80 60 40 Forward run with true emission rate and 40 m x 40 m resolution ART reconstruction with 0 m x 0 m resolution
40 Hypothetical BEE-TEX Scenario True Concentration (micrograms/m 3 ) C6H6 Final Concentration (micrograms/m 3 ) 1400 1400 Inferred 10 0 10 0 emission rates: y (m) 800 600 400 0 1401 160 60 260 280 240 300 2 0 180 80 340 360 3 40 y (m) 800 600 400 0 Target: 1.03 g/s Domain: 2.27 g/s 2 280 240 360 260 300 380 0 180 3 340 1 140 40 160 400 60 180 80 60 0 40 60 1 80 40 80 80 160 140 40 60 0 400 600 800 0 10 1400 x (m) 0 400 600 800 0 10 1400 x (m) Forward run with true emission rate and 40 m x 40 m resolution CAT-4Dvar reconstruction with m x m resolution
Real Time Data Broadcasting BEE-TEX data may be broadcast to a select number of field study participants in real time. Level 1 (ART) CAT-DOAS plume reconstructions HARC mobile lab PTR-MS observations Level 1 inverse modeling results (no chemistry). Data broadcasting will enable adaptive monitoring of emission events and other interesting conditions.