Volume 1 - The Atmospheric Studies Group at TRC
Volume 1 - The Atmospheric Studies Group at TRC Volume 1 - The Atmospheric Studies Group at TRC
Oresund A total of 16 CALPUFF simulations are run for each experiment-hour in the Oresund dataset to explore the sensitivity of model performance to the 4 CALMET configurations associated with mixing height computations and the 2 CALPUFF configurations associated with the choice for minimum σ v . Predicted and observed concentrations for all of these simulations are listed in Tables 4-17 and 4-18. Analysis of these results leads to the following conclusions: • The choice for the convective mixing height model can change individual arc-peak concentrations in the Oresund dataset by about 20%. On average, the Batchvarova–Gryning option (IMIXH=2) reduces these peak concentrations by about 10% from those obtained with the Maul-Carson option (IMIXH=1). • The choice of either calculated overwater mixing height or using the heights estimated from the temperature profiles over the strait (listed in Table 4-10) can change individual arc-peak concentrations in the Oresund dataset by about 20%. On average, computing an overwater mixing height increases these peak concentrations by about 3% to 6% from those obtained with the estimated heights. • Using either 0.5 m/s or 0.37 m/s for the minimum calculated σ v has no effect on simulations of the three releases from the Gladsaxe tower in Denmark. The initial 7 km transport across this built-up area, plus the lack of a very stable overwater boundary layer during these releases appears to promote computed σ v values at puff height that exceed both of these minimums. For the Barseback, Sweden releases, using 0.37 m/s for the minimum σ v increases the arc-peak concentrations by 10% to 40% compared to results obtained with using 0.5 m/s. All of the releases from the Barseback tower experience little initial over land transport, and the air temperatures on these days is significantly warmer than the Oresund temperatures, producing a stable overwater boundary layer. • None of these conclusions include an assessment of which of these choices performs best because in four of the nine experiments the results show a large overprediction tendency that is well beyond the 10% to 40% changes noted above. Further consideration of the dispersion conditions captured in the Oresund experiments suggests that turbulence advection, particularly in the offshore flow when the overwater turbulence is much weaker than that over land, must be explicitly simulated in order to improve performance. A test algorithm introduces this feature Final Report Vol.1 82
into CALPUFF, and the simulations are repeated. Revised predicted and observed concentrations are listed in Tables 4-19 and 4-20. Analysis of these results with turbulence advection leads to the following conclusions: • On average, the Batchvarova–Gryning option (IMIXH=2) reduces individual arc-peak concentrations in the Oresund dataset by about 10% from those obtained with the Maul-Carson option (IMIXH=1). Similarly, computing an overwater mixing height increases these arc-peak concentrations by about 3% to 6% from those obtained with the estimated heights. While this average behavior with the turbulence advection adjustment is nearly the same as that without it, changes in the individual arc-peak concentrations cover a slightly smaller range. • Using either 0.5 m/s or 0.37 m/s for the minimum calculated σ v has no effect on simulations of the three releases from the Gladsaxe tower in Denmark, and only about a 5% effect on releases from the Barseback, Sweden tower. With turbulence advection, σ v exceeds both minimum values over a longer portion of the trajectory across the strait. • Advected turbulence increases the diffusion of the Barseback releases as the tracer is transported across the Oresund, reducing the tendency of the model to overpredict peak concentrations at the opposite shore. It has virtually no influence on the impact of the Gladsaxe releases because these are already mixed substantially before reaching the Oresund, and turbulence levels over the Oresund are not as small as during the Barseback releases. • The prototype model for OCS applications should be modified to include turbulence advection. With this addition, it has a small mean bias toward overprediction, and exhibits scatter that is typical in that it is close to a factor of two. • The performance of CALPUFF with turbulence advection improves (smaller bias) when the Batchvarova – Gryning convective mixing height model is selected (IMIXH=2). This improvement is statistically significant at the 95% confidence level. Final Report Vol.1 83
- Page 33 and 34: Table 4-2b Over-water Meteorologica
- Page 35 and 36: Meteorological data used in the OCD
- Page 37 and 38: . . CARPINTERIA, CA 3814 . UTM Nort
- Page 39 and 40: Year Month Day Table 4-4 Over-water
- Page 41 and 42: Datum: NAS-C (North American 1927)
- Page 43 and 44: Table 4-5 Source Characterization f
- Page 45 and 46: Table 4-6a Over-water Meteorologica
- Page 47 and 48: Geophysical Processing Gridded land
- Page 49 and 50: Table 4-7 Source Characterization f
- Page 51 and 52: tape format called GF-3. These data
- Page 53 and 54: . . Strait of Oresund 6230 6220 UTM
- Page 55 and 56: . . Strait of Oresund 6230 6220 UTM
- Page 57 and 58: Table 4-10 SEA.DAT Meteorological D
- Page 59 and 60: the numbers refer to ICOARE values,
- Page 61 and 62: that are simulated during the one-h
- Page 63 and 64: 4.3 Evaluation Results Cameron, Car
- Page 65 and 66: improve model performance relative
- Page 67 and 68: Figure 4-7. Graphical depiction of
- Page 69 and 70: Figure 4-8. Graphical depiction of
- Page 71 and 72: Figure 4-9. Graphical depiction of
- Page 73 and 74: Figure 4-10. Graphical depiction of
- Page 75 and 76: Table 4-15 Performance Statistics f
- Page 77 and 78: Performance of CALPUFF Configuratio
- Page 79 and 80: Table 4-16 Performance Statistics f
- Page 81 and 82: Table 4-16 (continued) Performance
- Page 83: Figure 4-12. Graphical depiction of
- Page 87 and 88: Table 4-18 Oresund Results with Min
- Page 89 and 90: Table 4-20 Oresund Results with Min
- Page 91 and 92: Table 4-21 Performance Statistics f
- Page 93 and 94: 4.4 Recommendations A minimum σ v
- Page 95 and 96: SEA.DAT and OZONE.DAT files are pro
- Page 97 and 98: 36 34 32 30 Latitude 28 26 24 22 -1
- Page 99 and 100: WMO Number WBAN Number Station Iden
- Page 101 and 102: WMO Number WBAN Number Station Iden
- Page 103 and 104: WMO Number WBAN Number Station Iden
- Page 105 and 106: 36 72363 72340 34 72249 72248 72235
- Page 107 and 108: 36 34 32 41008 30 42035 42007 42040
- Page 109 and 110: 36 34 32 30 Latitude 28 26 24 22 -1
- Page 111 and 112: COOP State Station Name Table 5-4.
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- Page 115 and 116: Table 5-4. (Concluded) Hourly NWS P
- Page 117 and 118: Table 5-5. Ozone Stations Station I
- Page 119 and 120: Table 5-5. (Continued) Ozone Statio
- Page 121 and 122: Table 5-5. (Continued) Ozone Statio
- Page 123 and 124: 36 317 339 361 383 405 427 449 471
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- Page 127 and 128: 6. REFERENCES Batchvarova, E. and S
- Page 129 and 130: Maat, N., C. Kraan, and W.A. Oost,
- Page 131: APPENDIX: COMPILATION OF A HIGH RES
into CALPUFF, and the simul<strong>at</strong>ions are repe<strong>at</strong>ed. Revised predicted and observed<br />
concentr<strong>at</strong>ions are listed in Tables 4-19 and 4-20.<br />
Analysis of these results with turbulence advection leads to the following<br />
conclusions:<br />
• On average, the B<strong>at</strong>chvarova–Gryning option (IMIXH=2) reduces individual<br />
arc-peak concentr<strong>at</strong>ions in the Oresund d<strong>at</strong>aset by about 10% from those<br />
obtained with the Maul-Carson option (IMIXH=1). Similarly, computing an<br />
overw<strong>at</strong>er mixing height increases these arc-peak concentr<strong>at</strong>ions by about<br />
3% to 6% from those obtained with the estim<strong>at</strong>ed heights. While this<br />
average behavior with the turbulence advection adjustment is nearly the same<br />
as th<strong>at</strong> without it, changes in the individual arc-peak concentr<strong>at</strong>ions cover a<br />
slightly smaller range.<br />
• Using either 0.5 m/s or 0.37 m/s for the minimum calcul<strong>at</strong>ed σ v has no effect<br />
on simul<strong>at</strong>ions of the three releases from the Gladsaxe tower in Denmark,<br />
and only about a 5% effect on releases from the Barseback, Sweden tower.<br />
With turbulence advection, σ v exceeds both minimum values over a longer<br />
portion of the trajectory across the strait.<br />
• Advected turbulence increases the diffusion of the Barseback releases as the<br />
tracer is transported across the Oresund, reducing the tendency of the model<br />
to overpredict peak concentr<strong>at</strong>ions <strong>at</strong> the opposite shore. It has virtually no<br />
influence on the impact of the Gladsaxe releases because these are already<br />
mixed substantially before reaching the Oresund, and turbulence levels over<br />
the Oresund are not as small as during the Barseback releases.<br />
• <strong>The</strong> prototype model for OCS applic<strong>at</strong>ions should be modified to include<br />
turbulence advection. With this addition, it has a small mean bias toward<br />
overprediction, and exhibits sc<strong>at</strong>ter th<strong>at</strong> is typical in th<strong>at</strong> it is close to a factor<br />
of two.<br />
• <strong>The</strong> performance of CALPUFF with turbulence advection improves (smaller<br />
bias) when the B<strong>at</strong>chvarova – Gryning convective mixing height model is<br />
selected (IMIXH=2). This improvement is st<strong>at</strong>istically significant <strong>at</strong> the 95%<br />
confidence level.<br />
Final Report Vol.1 83
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