Performance characteristics of MM5-SMOKE-CMAQ for a summer photochemical episode in southeast England, United Kingdom

Abstract In this study a modelling system consisting of Mesoscale Model (MM5), Sparse Matrix Operator Kernel Emissions (SMOKE) and Community Multiscale Air Quality (CMAQ) model has been applied to a summer photochemical period in southeast England, UK. Ozone (O 3 ), nitrogen dioxide (NO 2 ) and particulate matter (PM 2.5 ) concentrations modelled with different horizontal grid resolutions (9 and 3 km) were evaluated against available ground-level observations from the UK Automatic Urban and Rural Network (AURN) and London Air Quality Network (LAQN) for the period of 24–28 June 2001 with a focus on O 3 predictions. This effort, which represents the first comprehensive performance evaluation of the modelling system over a UK domain, reveals that CMAQ's ability to reproduce surface O 3 observations varies with O 3 concentrations. It underpredicts O 3 mixing ratios on high-O 3 days and overpredicts the maximum and minimum hourly O 3 values for most low-O 3 days. Model sensitivity analysis with doubled anthropogenic NO x or volatile organic compounds (VOC) emissions and analysis of the daylight-averaged levels of OX (sum of O 3 and NO 2 ) as a function of NO x revealed that the undereprediction of peak O 3 concentrations on high-O 3 days is caused by the underprediction of regional contribution and to a lesser extent local production, which might be related to the underestimation of European emissions in EMEP inventory and the lacked reactivity of the modelled atmosphere. CMAQ systematically underpredicts hourly NO 2 mixing ratios but captures the temporal variations. The normalized mean bias for hourly NO 2 , although much larger than that for O 3 , falls well within the generally accepted range of −20% to −50%. CMAQ with both resolutions (9 and 3 km) significantly underpredicts PM 2.5 mass concentrations and fails to reproduce its temporal variations. While model performance for O 3 and PM 2.5 are not very sensitive to model grid resolutions, a better agreement between modelled and measured hourly NO 2 mixing ratios was achieved with higher resolution. Further investigation into the uncertainties in meteorological input, uncertainties in emissions, as well as representation of physical and chemical processes (e.g. chemical mechanism) in the model is needed to identify the causes for the discrepancies between observations and predictions.

[1]  Seungbum Kim,et al.  Evaluation of air quality models for the simulation of a high ozone episode in the Houston metropolitan area , 2007 .

[2]  C. N. Hewitt,et al.  A global model of natural volatile organic compound emissions , 1995 .

[3]  Gary Koop,et al.  An investigation of thresholds in air pollution-mortality effects , 2006, Environ. Model. Softw..

[4]  Robert Vautard,et al.  A comparison of simulated and observed ozone mixing ratios for the summer of 1998 in Western Europe , 2001 .

[5]  Robert E. Davis,et al.  Statistics for the evaluation and comparison of models , 1985 .

[6]  Shuiyuan Cheng,et al.  An integrated MM5–CMAQ modeling approach for assessing trans-boundary PM10 contribution to the host city of 2008 Olympic summer games—Beijing, China , 2007 .

[7]  K. Clemitshaw,et al.  Ozone and other secondary photochemical pollutants: chemical processes governing their formation in the planetary boundary layer , 2000 .

[8]  J. D. Whyatt,et al.  The Regional Distribution of Ozone Across the British Isles and its Response to Control Strategies. , 2002 .

[9]  R. Derwent,et al.  Photochemical ozone formation in north west Europe and its control , 2003 .

[10]  David S. Lee,et al.  Modelling the contribution of different sources of sulphur to atmospheric deposition in the United Kingdom , 2000 .

[11]  Christian Seigneur,et al.  A comprehensive performance evaluation of MM5-CMAQ for the Summer 1999 Southern Oxidants Study episode—Part II: Gas and aerosol predictions , 2006 .

[12]  S. Hanna,et al.  Evaluation of photochemical grid models (UAM-IV, UAM-V, and the ROM/UAM-IV couple) using data from the lake michigan ozone study (LMOS) , 1996 .

[13]  Pedro Jiménez,et al.  Influence of initial and boundary conditions for ozone modeling in very complex terrains: A case study in the northeastern Iberian Peninsula , 2007, Environ. Model. Softw..

[14]  N. Englert.  Fine particles and human health--a review of epidemiological studies. , 2004, Toxicology letters.

[15]  H. Fernando,et al.  Evaluation of Meteorological Models MM5 and HOTMAC Using PAFEX-I Data , 2004 .

[16]  Shaocai Yu,et al.  A performance evaluation of the 2004 release of Models-3 CMAQ , 2006 .

[17]  Robin L. Dennis,et al.  NARSTO critical review of photochemical models and modeling , 2000 .

[18]  Christian Seigneur,et al.  A comprehensive performance evaluation of MM5-CMAQ for the summer 1999 southern oxidants study episode, Part III: Diagnostic and mechanistic evaluations , 2006 .

[19]  S. Dorling.  Ozone in the United Kingdom , 2009 .

[20]  Weimin Jiang,et al.  Evaluation of CMAQ O3 and PM2.5 performance using Pacific 2001 measurement data , 2006 .

[21]  M. Jenkin,et al.  Analysis of the relationship between ambient levels of O3, NO2 and NO as a function of NOx in the UK , 2001 .

[22]  W. Collins,et al.  Modelling of tropospheric ozone formation , 2000 .

[23]  Meigen Zhang,et al.  A Three-Dimensional Simulation of HOx Concentrations Over East Asia During TRACE-P , 2006 .

[24]  Philippe Thunis,et al.  Evaluation and intercomparison of Ozone and PM10 simulations by several chemistry transport models over four European cities within the CityDelta project , 2007 .

[25]  Roberto San José García,et al.  Prediction of ozone levels in London using the MM5-CMAQ modelling system , 2006, Environ. Model. Softw..

[26]  Christian Seigneur,et al.  Current Status of Air Quality Models for Particulate Matter , 2001, Journal of the Air & Waste Management Association.

[27]  C. N. Hewitt,et al.  Ozone in the United Kingdom - Fourth Report of the Photochemical Oxidants Review Group - 1997 , 1997 .

[28]  Patrick L. Kinney,et al.  Simulating regional-scale ozone climatology over the eastern United States: model evaluation results , 2004 .

[29]  Mark Jacob,et al.  Ozone photochemistry and elevated isoprene during the UK heatwave of august 2003 , 2006 .

[30]  G. Ancellet,et al.  Observed and modelled “chemical weather” during ESCOMPTE , 2005 .

[31]  M. Jenkin,et al.  The Temporal Dependence of Ozone Precursor Emissions: Estimation and Application , 2000 .

[32]  D. Stevenson,et al.  Tropospheric Ozone in a Global-Scale Three-Dimensional Lagrangian Model and Its Response to NOX Emission Controls , 1997 .

[33]  R. Vautard,et al.  Aerosol modeling with CHIMERE—preliminary evaluation at the continental scale , 2004 .

[34]  E. Berge,et al.  A study of the importance of initial conditions for photochemical oxidant modeling , 2001 .

[35]  Gerhard Wotawa,et al.  A European inventory of soil nitric oxide emissions and the effect of these emissions on the photochemical formation of ozone , 1996 .