Seasonal Modeling of the Export of Pollutants from North America using the Multiscale Air Quality Simulation Platform

(MAQSIP)

Adel Hanna,1 Rohit Mathur,1 Carey Jang2

and

Joseph Pinto2

 1 Environmental Programs

MCNC-North Carolina Supercomputing Center

P.O. Box 12889

Research Triangle Park, NC 27709-2889

USA

 2 U. S. Environmental Protection Agency, USA

Outline

• Objectives• The Multiscale Air Quality Simulation Platform (MAQSIP)• The SMRAQ Seasonal Simulation• Selected Meteorological cases during the summer of 1995

• Analysis of Flux of CO and O3

• Vertical Cross Sections of the Zonal Flux of CO and O3

• Summary

Objectives

• Characterize possible meteorological patterns associated with the export of pollutants from North America during summer- 1995 case study

• Characterize the vertical distribution of the export

• Identify possible mechanisms associated with the export process

MAQSIP Structural Attributes

Modular. Each process module acts on a common trace species concentration field while other variables are represented within each individual module

Flexible. Alternate modules for process representation and/or numerical schemes; enables comprehensive module intercomparison; enables system to be customized to emulate other models

Expandable. New modules can be added by users; allows system to improve as science evolves

Multiscale. Multilevel nesting; adaptable to various scales and geographic regions (urban, regional, intercontinental)

Generalized Coordinates. Different map projections; interface with different meteorological models (e.g., CMAQ/RAMS/MM5)

A detailed description of MAQSIP can be found in (Mathur et al., 2001, and Odman et al., 1996,1998)

Seasonal Modeling for Regional Air Quality (SMRAQ)

• Modeling over Eastern United States for the summer of 1995 (May 15 – September 11)

• MAQSIP was run using horizontal resolution at 36 km and 22 sigma levels were used in the vertical (up to 100 mb )

• Meteorology was simulated by the MM5 exercised in a four dimensional data assimilation mode using analysis nudging and re-initialization every 5 days

• The MM5 model was run in a nested mode covering a domain larger than the MAQSIP domain (108 km resolution in the coarse grid out side the MAQSIP 36 km domain)

• Chemical Mechanism used in MAQSIP is the Carbon Bond Mechanism CB-IV) (version 4.2)

• Emissions (anthropogenic and Biogenic) were processed using MCNC-SMOKE (Houyoux et al., 1999)

• Time-invariant boundary concentrations were specified for this simulation: 35 ppb for O3 and 80 ppb for CO

Comparisons with Surface O3 Observations

• Average 10 am – 5 pm model and observed O3. Comparisons between values in different percentiles (10- blue, 25 - magenta, 50 - green, 75 - yellow, 90 - red) for the entire simulation period

• The comparisons are at 137 locations at which observations are available (“rural” AIRS sites within the domain)

(From: Kasibhatla and Chameides, Geophys.,

Res. Lett., Vol 27, 1415-1418, 2000)

SMRAQ ApplicationsBias (model-observation) of the seasonal mean ozone concentrations derived from hourly

concentrationsReference: Hogrefe et al. (2001)

Characterization of Synoptic Patterns

• Southwest flow at the surface ahead of a cold front approaching the Northeastern US. (e.g., June 7-8 and 10-11, 1995)

• A surface high pressure extending over the middle Atlantic and Northeastern US. An OMEGA pattern at 500 mb. Re-circulation over the Southeastern US (e.g. June 16-17-18, 1995)

• A surface low pressure over central US June and OMEGA pattern at 500 mb (e.g. June 26 – 27, 1995)

• Large-scale circulation with surface high pressure and 500 mb high pressure (e.g., July 14 and 15, 1995)

Surface and 500 mb MeteorologyJune 7, 1995 June 8, 1995

CO Daily Average Flux (June 7 & 8)

CO Daily Average Flux- Above Background (June 7 & 8)

O3 Daily Average Flux (June 7 & 8)

O3 Daily Average Flux- Above Background (June 7 & 8)

Vertical Cross-Section of Zonal Flux- O3 (June 7 &8)

Vertical Cross-Section of Zonal Flux- CO (June 7 &8)

Surface and 500 mb Meteorology June 10, 1995 June 11, 1995

O3 Daily Average Flux (June 10 & 11)

Vertical Cross-Section of Zonal Flux – O3 (June 10 &11)

Surface and 500 mb Met (June 16 -17)

O3 Daily Average Flux (June 17& 18)

Vertical Cross-Section of Zonal Flux – O3 (June 16, 17,18)

Surface and 500 mb Meteorology June 26, 1995 June 27, 1995

O3 Daily Average Flux (June 26 & 27)

Vertical Cross-Section of Zonal Flux – O3 (June 26, 27)

Surface and 500 mb Meteorology July 14, 1995 July 15, 1995

Daily Ozone Max

O3 Daily Average Flux (July 14 & 15)

Vertical Cross-Section of Zonal Flux – O3 (July 14, 15)

SUMMARY

• The outflow from North America was characterized for a number of synoptic patterns

• Over a season location (horizontal and vertical) and magnitude of transport can change on a daily basis

• Future work– More detailed analysis of the time series of the outflow and

quantification of export– Extend analysis to other species– Expand modeling domain eastward to capture the re-circulation cases

and the export to Europe