Influence of lateral and top boundary conditions on regional air quality prediction: A multiscale study coupling regional and global chemical transport models

[1] The sensitivity of regional air quality model to various lateral and top boundary conditions is studied at 2 scales: a 60 km domain covering the whole USA and a 12 km domain over northeastern USA. Three global models (MOZART-NCAR, MOZART-GFDL and RAQMS) are used to drive the STEM-2K3 regional model with time-varied lateral and top boundary conditions (BCs). The regional simulations with different global BCs are examined using ICARTT aircraft measurements performed in the summer of 2004, and the simulations are shown to be sensitive to the boundary conditions from the global models, especially for relatively long-lived species, like CO and O3. Differences in the mean CO concentrations from three different global-model boundary conditions are as large as 40 ppbv, and the effects of the BCs on CO are shown to be important throughout the troposphere, even near surface. Top boundary conditions show strong effect on O3 predictions above 4 km. Over certain model grids, the model's sensitivity to BCs is found to depend not only on the distance from the domain's top and lateral boundaries, downwind/upwind situation, but also on regional emissions and species properties. The near-surface prediction over polluted area is usually not as sensitive to the variation of BCs, but to the magnitude of their background concentrations. We also test the sensitivity of model to temporal and spatial variations of the BCs by comparing the simulations with time-varied BCs to the corresponding simulations with time-mean and profile BCs. Removing the time variation of BCs leads to a significant bias on the variation prediction and sometime causes the bias in predicted mean values. The effect of model resolution on the BC sensitivity is also studied.

[1]  S. Gong,et al.  A parameterization of sea‐salt aerosol source function for sub‐ and super‐micron particles , 2003 .

[2]  Thomas E. Pierce,et al.  An improved model for estimating emissions of volatile organic compounds from forests in the eastern United States , 1994 .

[3]  Adrian Sandu,et al.  Chemical data assimilation of Transport and Chemical Evolution over the Pacific (TRACE-P) aircraft measurements , 2006 .

[4]  R. Martin,et al.  Chemical data assimilation estimates of continental U.S. ozone and nitrogen budgets during the Intercontinental Chemical Transport Experiment–North America , 2007 .

[5]  John C. Gille,et al.  Measurements of Pollution in the Troposphere (MOPITT) validation exercises during summer 2004 field campaigns over North America , 2007 .

[6]  C. Granier,et al.  Emissions of Atmospheric Trace Compounds , 2004 .

[7]  G. Grell,et al.  A description of the fifth-generation Penn State/NCAR Mesoscale Model (MM5) , 1994 .

[8]  J. Seinfeld,et al.  Three-dimensional simulations of inorganic aerosol distributions in east Asia during spring 2001 , 2004, Journal of Geophysical Research.

[9]  B. Hannegan,et al.  Stratospheric ozone in 3-D models : A simple chemistry and the cross-tropopause flux , 2000 .

[10]  William P. L. Carter,et al.  DOCUMENTATION OF THE SAPRC-99 CHEMICAL MECHANISM FOR VOC REACTIVITY ASSESSMENT VOLUME 1 OF 2 DOCUMENTATION TEXT , 1999 .

[11]  J. Penner,et al.  NOx from lightning 1. Global distribution based on lightning physics , 1997 .

[12]  Michael Q. Wang,et al.  An inventory of gaseous and primary aerosol emissions in Asia in the year 2000 , 2003 .

[13]  D. Jacob,et al.  Inventory of boreal fire emissions for North America in 2004 : Importance of peat burning and pyroconvective injection , 2007 .

[14]  Colin Price,et al.  Vertical distributions of lightning NOx for use in regional and global chemical transport models , 1998 .

[15]  Robert A. Harley,et al.  Effect of alternative boundary conditions on predicted ozone control strategy performance: A case study in the Los Angeles area , 1995 .

[16]  J. Seinfeld,et al.  Atmospheric Gas-Aerosol Equilibrium I. Thermodynamic Model , 1993 .

[17]  J. Seinfeld,et al.  Atmospheric gas−aerosol equilibrium. II: Analysis of common approximations and activity coefficient calculation methods , 1993 .

[18]  B. Duncan,et al.  A modeling study of the export pathways of pollution from Europe: Seasonal and interannual variations (1987–1997) , 2004 .

[19]  Carolyn P. Winn,et al.  The Rosenstiel School of Marine and Atmospheric Science , 1989 .

[20]  C. Lai,et al.  Photochemical modeling and analysis of meteorological parameters during ozone episodes in Kaohsiung, Taiwan , 2003 .

[21]  J. Lamarque,et al.  Quantifying CO emissions from the 2004 Alaskan wildfires using MOPITT CO data , 2005 .

[22]  Aaron L. Swanson,et al.  Effects of changing power plant NOx emissions on ozone in the eastern United States: Proof of concept , 2006 .

[23]  J. Lamarque,et al.  A global simulation of tropospheric ozone and related tracers: Description and evaluation of MOZART, version 2 , 2001 .

[24]  R. Martin,et al.  Chemical Data Assimilation Estimates of Continental US Ozone and Nitrogen Budgets during INTEX-A , 2007 .

[25]  Adrian Sandu,et al.  Adjoint sensitivity analysis of regional air quality models , 2005 .

[26]  H. Pan,et al.  Nonlocal Boundary Layer Vertical Diffusion in a Medium-Range Forecast Model , 1996 .

[27]  Edward V. Browell,et al.  Regional Air Quality Modeling System (RAQMS) predictions of the tropospheric ozone budget over east Asia , 2003 .

[28]  J. Seinfeld,et al.  Atmospheric Gas–Aerosol Equilibrium: III. Thermodynamics of Crustal Elements Ca2+, K+, and Mg2+ , 1995 .

[29]  J. Lamarque,et al.  Observational constraints on the chemistry of isoprene nitrates over the eastern United States , 2007 .

[30]  Jung-Hun Woo,et al.  Impacts of aerosols and clouds on photolysis frequencies and photochemistry during TRACE-P: 2. Three-dimensional study using a regional chemical transport model , 2003 .

[31]  David Sims,et al.  MEDIA ADVISORY US Senator John Sununu to Attend NASA Briefing at UNHs Institute for the Study of Earth, Oceans, and Space , 2005 .

[32]  D. Fahey,et al.  The 1995 scientific assessment of the atmospheric effects of stratospheric aircraft , 1995 .

[33]  William P L Carter,et al.  Documentation of the SAPRC-99 chemical mechanism for VOC reactivity assessment. Volume 2. , 2000 .