Comparisons of JU2003 observations with four diagnostic urban wind flow and Lagrangian particle dispersion models

Hanna, Steven R.; White, John; Trolier, James W.; Vernot, Rebecca; Brown, Michael J.; Gowardhan, Akshay; Kaplan, H.; Alexander, Y.; Moussafir, Jacques; Wang, Yansen; Williamson, Chatt; Hannan, John R.; Hendrick, Elizabeth

doi:10.1016/j.atmosenv.2011.03.058

Cited by 62 publications

(41 citation statements)

References 18 publications

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“…The LLNL samplers were mostly in the area within a few blocks of the release, and most of them were closer to the release than the ARL-FRD samplers. Hanna et al (2011) included both the ARL-FRD and the LLNL samplers in their evaluations of four diagnostic urban wind flow and Lagrangian particle dispersion models, but the current JEM exercise made use of just the ARL-FRD samplers.…”

Section: U2000 In Salt Lake City (Slc)mentioning

confidence: 99%

Acceptance criteria for urban dispersion model evaluation

Hanna¹,

Chang

2012

Meteorol Atmos Phys

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The authors suggested acceptance criteria for rural dispersion models' performance measures in this journal in 2004. The current paper suggests modified values of acceptance criteria for urban applications and tests them with tracer data from four urban field experiments. For the arc-maximum concentrations, the fractional bias should have a magnitude\0.67 (i.e., the relative mean bias is less than a factor of 2); the normalized mean-square error should be \6 (i.e., the random scatter is less than about 2.4 times the mean); and the fraction of predictions that are within a factor of two of the observations (FAC2) should be [0.3. For all data paired in space, for which a threshold concentration must always be defined, the normalized absolute difference should be \0.50, when the threshold is three times the instrument's limit of quantification (LOQ). An overall criterion is then applied that the total set of acceptance criteria should be satisfied in at least half of the field experiments. These acceptance criteria are applied to evaluations of the US Department of Defense's Joint Effects Model (JEM) with tracer data from US urban field experiments in Salt Lake City (U2000), Oklahoma City (JU2003), and Manhattan (MSG05 and MID05). JEM includes the SCIPUFF dispersion model with the urban canopy option and the urban dispersion model (UDM) option. In each set of evaluations, three or four likely options are tested for meteorological inputs (e.g., a local building top wind speed, the closest National Weather Service airport observations, or outputs from numerical weather prediction models). It is found that, due to large natural variability in the urban data, there is not a large difference between the performance measures for the two model options and the three or four meteorological input options. The more detailed UDM and the state-of-the-art numerical weather models do provide a slight improvement over the other options. The proposed urban dispersion model acceptance criteria are satisfied at over half of the field experiments.

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Section: U2000 In Salt Lake City (Slc)mentioning

confidence: 99%

Acceptance criteria for urban dispersion model evaluation

Hanna¹,

Chang

2012

Meteorol Atmos Phys

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230

124

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“…The focus of this field campaign is to better understand atmospheric dispersion process of a tracer gas in urban environments under varying atmospheric conditions. Therefore, many model researchers used the detailed meteorological and concentration data for model evaluation study (Wyszogrodzki et al [15], Warner et al [23], Chan and Leach [24], Hendricks et al [25], and Hanna et al [26]). …”

Section: Dataset Of the Field Experiments For Estimating Prediction Amentioning

confidence: 99%

Development ofLOcal-scaleHigh-resolution atmosphericDIspersionModel usingLarge-EddySimulation. Part 5: detailed simulation of turbulent flows and plume dispersion in an actual urban area under real meteorological conditions

Nakayama

Takemi

Nagai

2015

Journal of Nuclear Science and Technology

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We have developed a LOcal-scale High-resolution atmospheric DIspersion Model using Large-Eddy Simulation (LOHDIM-LES) to assess the safety at nuclear facilities and to respond to emergency situations resulting from accidental or deliberate releases of radioactive materials (e.g., a terrorist attack in an urban area). In parts 1-4, LESs of turbulent flows and plume dispersion over a flat terrain, around an isolated building, within building arrays with different obstacle densities, and within an actual urban area were performed, which showed the basic performance comparable to wind tunnel experimental technique. In this study, we extend the LOHDIM-LES to turbulent flows and plume dispersion in an actual urban area under real meteorological conditions by coupling with a meso-scale meteorological simulation model. The LES results of wind speed, wind direction, and concentration values are generally reproduced well. It is concluded that our coupling approach between LES and meso-scale meteorological models is effective in detailed simulations of turbulent flows and plume dispersion in urban areas under real meteorological conditions.

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“…In an earlier comparison of four urban dispersion models with observations from two surface-level SF 6 tracer releases during the Oklahoma City Joint Urban 2003 (JU2003) field experiment, it was found that, although there was much uncertainty or variability in the concentration fields, the models underpredicted the skyscraper rooftop concentrations and the ratios of rooftop to surface concentrations near the release location (Hanna et al, 2011). For example, during one tracer release, a rooftop sampler was on the Bank One building (z ¼ 148 m) at a distance 82 m NNE of the release, and a ratio of rooftop to surface concentration of about 0.13 was observed.…”

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confidence: 94%