Assessment of Dust Emissions Model and PM10 in the United Arab Emirates during Dust Storms using the CMAQ-WRF Modeling System
Abstract
An air quality model was applied to predict ambient concentrations of particulate matter (PM) below 10 μm in aerodynamic diameter (PM10) from dust storms in the summer of 2007 in the United Arab Emirates (UAE), where dust emissions are the dominant source of PM10. The aim was to investigate the performance of an advanced dust emissions parameterization (DUST_EI) from the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model in predicting ambient concentrations of dust, compared to that of SimpleDust, a simplified dust emissions parameterization used to generate dust emissions for the Community Multiscale Air Quality Model (CMAQ). The DUST_EI model aggregates dust emissions calculated in each of 10 size bins, yielding a variable ratio of fine to coarse PM emissions, compared to the fixed ratio used in SimpleDust. It also uses a temporally and spatially varying threshold friction velocity, a key parameter for initiating dust events, in contrast to the constant value used in SimpleDust Dust emissions from the two dust models were combined with emissions from other sources and input into CMAQ version 4.7 in air quality simulations for May to August, 2007. Relative to the SimpleDust model, seasonal total (fine + coarse) dust emissions estimated by the DUST_EI model increased by a factor of 2.4, and by a factor of 5 when summed over the fine size bins only. The SimpleDust model shows a consistent low bias of up to -87% compared to PM10 surface observations. On the other hand, biases at four surface PM10 monitors ranged from -10% to +36% with DUST_EI, which was also able to reproduce the timing and location of dust storms, but tended to under-predict PM10 during dust storm days. The parameterized DUST_EI model should be revised using observations of both PM10 and PM2.5 collected over a longer duration and more locations to improve the representation of dust emissions in this region.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFM.A41G0138F
- Keywords:
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- 3311 ATMOSPHERIC PROCESSES Clouds and aerosols