Air quality modelling using the Met Office Unified Model (AQUM OS24-26): model description and initial evaluation
-
Published:2013-03-12
Issue:2
Volume:6
Page:353-372
-
ISSN:1991-9603
-
Container-title:Geoscientific Model Development
-
language:en
-
Short-container-title:Geosci. Model Dev.
Author:
Savage N. H.ORCID, Agnew P., Davis L. S., Ordóñez C.ORCID, Thorpe R., Johnson C. E., O'Connor F. M., Dalvi M.
Abstract
Abstract. The on-line air quality model AQUM (Air Quality in the Unified Model) is a limited-area forecast configuration of the Met Office Unified Model which uses the UKCA (UK Chemistry and Aerosols) sub-model. AQUM has been developed with two aims: as an operational system to deliver regional air quality forecasts and as a modelling system to conduct air quality studies to inform policy decisions on emissions controls. This paper presents a description of the model and the methods used to evaluate the performance of the forecast system against the automated UK surface network of air quality monitors. Results are presented of evaluation studies conducted for a year-long period of operational forecast trials and several past cases of poor air quality episodes. The results demonstrate that AQUM tends to over-predict ozone (~8 μg m−3 mean bias for the year-long forecast), but has a good level of responsiveness to elevated ozone episode conditions – a characteristic which is essential for forecasting poor air quality episodes. AQUM is shown to have a negative bias for PM10, while for PM2.5 the negative bias is much smaller in magnitude. An analysis of speciated PM2.5 data during an episode of elevated particulate matter (PM) suggests that the PM bias occurs mainly in the coarse component. The sensitivity of model predictions to lateral boundary conditions (LBCs) has been assessed by using LBCs from two different global reanalyses and by comparing the standard, single-nested configuration with a configuration having an intermediate European nest. We conclude that, even with a much larger regional domain, the LBCs remain an important source of model error for relatively long-lived pollutants such as ozone. To place the model performance in context we compare AQUM ozone forecasts with those of another forecasting system, the MACC (Monitoring Atmospheric Composition and Climate) ensemble, for a 5-month period. An analysis of the variation of model skill with forecast lead time is presented and the insights this provides to the relative sources of error in air quality modelling are discussed.
Publisher
Copernicus GmbH
Reference62 articles.
1. Ackermann, I. H., Hass, H., Memmesheimer, M., Ziegenbein, C., and Ebel, A.: The parametrization of the sulphate-nitrate-ammonia aerosol system in the long-range transport model EURAD, Meteorol. Atmos. Phys., 57, 101–114, 1995. 2. Agnew, P., Mittermaier, M. P., Honore, C., Elbern, H., Coll, I., Vautard, R., and Peuch., V.-H.: Evaluation of GEMS regional air quality forecasts, GEMS project report, available at: http://gems.ecmwf.int/do/get/PublicDocuments/1533/1402?showfile=true (last access: 4 January 2013), 2007. 3. Andres, R. J. and Kasgnoc, A. D.: A time-averaged inventory of sub-aerial volcanic sulfur emissions, J. Geophys. Res. Atmos., 103, 25251–25261, 1998. 4. Bellouin, N., Rae, J., Jones, A., Johnson, C., Haywood, J., and Boucher, O.: Aerosol forcing in the Climate Model Intercomparison Project (CMIP5) simulations by HadGEM2-ES and the role of ammonium nitrate, J. Geophys Res.-Atmos., 116, D20206, https://doi.org/10.1029/2011JD016074, 2011. 5. Bellouin, N., Mann, G. W., Woodhouse, M. T., Johnson, C., Carslaw, K. S., and Dalvi, M.: Impact of the modal aerosol scheme GLOMAP-mode on aerosol forcing in the Hadley Centre Global Environmental Model, Atmos. Chem. Phys. Discuss., 12, 21437–21479, https://doi.org/10.5194/acpd-12-21437-2012, 2012.
Cited by
98 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献
|
|