Calendar Event Details
AEROCENTER: Charlie Stanier
Affiliation: University of Iowa
Event Date: Tuesday, November 19, 2013
Location: G133
Time: 11:00 AM
Applying CMAQ, MODIS, and Surface Observations to Air Quality Applications in the United States
Charles O. Stanier
Associate Professor, Chemical & Biochemical Engineering
and IIHR Hydroscience and Engineering
University of Iowa
Visiting Associate Professor, Atmospheric and Oceanic Science
University of Maryland
email: charles-stanier@uiowa.edu
Two air quality applications will be investigated. Aspects of regional wintertime air quality in the Upper Midwest will be investigated through an overview of the LADCO (Lake Michigan Air Directors Consortium) Winter Nitrate Study (WNS). Areas throughout the Great Lakes and Upper Midwest experience multiday episodes of wintertime PM2.5 pollution characterized by high fractions of ammonium nitrate in PM, low wind speeds, and air mass stagnation. For example Milwaukee, WI experienced 13 PM2.5 episodes during the 3 month study period of the LADCO WNS. Episodes were characterized by low pressure systems, shallow/stable boundary layer, light winds, and increased temperature and relative humidity relative to climatological mean conditions. They often occurred in the presence of regional snow cover at temperatures near freezing, when snow melt and sublimation could generate fog and strengthen the boundary layer inversion. In an 800,000 km2 area characterized by peak wintertime total nitrate concentrations, the nighttime pathway was responsible for 72% of nitrate formation in the lower troposphere (0-3km), including both heterogeneous (57%) and homogeneous (15%) conversion of N2O5 to nitrate. Vertical gradients of the key reactions and gas- and aerosol-phase components are investigated.
In the second application, the approaches for merging observations (MODIS AOD, IMPROVE PM2.5 observations, and EPA AQS observations) with air quality models will be discussed, with a focus on the development of improved seasonal and annual surface PM2.5 concentration predictions for use by the aerosol health effects community. The improvements and limitations of optimal interpolation as a technique for merging air quality model and observations will be discussed, and the sensitivity of results to the selection of the MODIS input (Level 2 or the USNRL L3 product) are quantified.
Posted or updated: Friday, October 25, 2013
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