procanal

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PROCESS-BASED ANALYSIS OF THE ROLE OF THE GULF BREEZE IN SIMULATING OZONE CONCENTRATIONS ALONG THE EASTERN GULF COAST Sharon G. Douglas Jay L. Haney Ana R. Alvarez ICF Consulting/SAI San Rafael, California AMS/AWMA 11th Joint Conference on Air Pollution Meteorology Paper 6.4

Overview of the UAM-V Process Analysis Technique: 

Overview of the UAM-V Process Analysis Technique Concept introduced by Jeffries and Tonnesen (1994) As implemented in UAM-V, provides detailed information on the physical and chemical process that occur during a simulation Process-level information includes photochemical production/consumption horizontal advection/diffusion vertical advection vertical diffusion deposition emissions (for precursor pollutants)

Typical Uses of UAM-V Process Analysis: 

Typical Uses of UAM-V Process Analysis Model performance evaluation and diagnostic analysis Examination of the response of the UAM-V modeling system to emission reductions Obtaining an improved understanding of the modeling results through quantification of the various simulation processes

Gulf Coast Ozone Study Modeling/Analysis Components: 

Gulf Coast Ozone Study Modeling/Analysis Components Episode selection (using an objective/regional optimization approach)  4 multi-day simulation periods Detailed emission inventory preparation (incorporating data from participating states and industries) Meteorological and photochemical modeling (using MM5 and an enhanced version of UAM-V) Future-year modeling for 2005/Examination of regional and sub-regional attainment strategies Corroborative analyses of observed data

Gulf Coast Ozone Study UAM-V Modeling Domain: 

Gulf Coast Ozone Study UAM-V Modeling Domain Approximate process analysis subregion 4 km grid FL,AL,MS,LA Gulf Coast

Simulated Process Contributions to Ozone for Pensacola: 16 September 1997: 

Simulated Process Contributions to Ozone for Pensacola: 16 September 1997 Ozone ppb Hour 0 100 Simulated — and observed ozone concentration

Simulated Process Contributions to Ozone for Pensacola: 16 September 1997: 

Simulated Process Contributions to Ozone for Pensacola: 16 September 1997 Ozone ppb Hour 0 100 Simulated — and observed ozone concentration

Simulated Process Contributions to Ozone for Pensacola: 16 September 1997: 

Simulated Process Contributions to Ozone for Pensacola: 16 September 1997 Ozone ppb Hour 0 100 Simulated — and observed ozone concentration

Simulated Process Contributions to Ozone for Pensacola: 16 September 1997: 

Simulated Process Contributions to Ozone for Pensacola: 16 September 1997 Ozone ppb Hour 0 100 Simulated — and observed ozone concentration

Simulated Process Contributions to Ozone for Pensacola: 16 September 1997: 

Simulated Process Contributions to Ozone for Pensacola: 16 September 1997 Ozone ppb Hour 0 100 Simulated — and observed ozone concentration Onset of the gulf breeze

Simulated Process Contributions to Ozone for Pensacola: 16 September 1997: 

Simulated Process Contributions to Ozone for Pensacola: 16 September 1997 Ozone ppb Hour 0 100 Simulated — and observed ozone concentration Breakup of the nocturnal inversion

Simulated Process Contributions to Ozone for Pensacola: 16 September 1997: 

Simulated Process Contributions to Ozone for Pensacola: 16 September 1997 Ozone ppb Hour 0 100 Simulated — and observed ozone concentration Ozone production reverses when the effective mixing height collapses

Simulated Process Contributions to Ozone for Pensacola: 16 September 1997: 

Simulated Process Contributions to Ozone for Pensacola: 16 September 1997 Ozone ppb Hour 0 100 Simulated — and observed ozone concentration Advection of ozone by the gulf breeze appears to contribute to the sustained/secondary peak

Simulated Process Contributions to Ozone for Pensacola: 16 September 1997: 

Simulated Process Contributions to Ozone for Pensacola: 16 September 1997 Ozone ppb Hour 0 100 Simulated — and observed ozone concentration

KEY FINDINGS RELATED TO THE ROLE OF THE GULF BREEZE: 

KEY FINDINGS RELATED TO THE ROLE OF THE GULF BREEZE MM5 produces a gulf breeze circulation (that is consistent with conceptual models) Horizontal advection of ozone into the region by the gulf breeze contributes to the sustained/secondary ozone peak on 16 September (as well as several other of the simulation days) Recirculation of ozone by the gulf breeze may explain why areas along the gulf coast are potential non-attainment areas for 8-hour ozone (but not for 1-hour ozone) — gulf breeze extends the period over which relatively high ozone concentrations occur

OTHER KEY FINDINGS FROM USING PROCESS ANALYSIS AS PART OF GCOS: 

OTHER KEY FINDINGS FROM USING PROCESS ANALYSIS AS PART OF GCOS Vertical resolution of the UAM-V there appears to be a point beyond which increased vertical resolution does not enhance representation of the meteorological/simulation processes for the GCOS modeling platform, use of more than 8 model layers does not alter the relative contribution of simulation processes Deposition deposition becomes negligible under very light wind speed conditions modified/enhanced the calculation of friction velocity (u*) for use in the deposition algorithm