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Evaluation of the Community Multiscale Air Quality Model for Simulating Winter Ozone Formation in the Uinta Basin
Author(s) -
Matichuk Rebecca,
Tonnesen Gail,
Luecken Deborah,
Gilliam Rob,
Napelenok Sergey L.,
Baker Kirk R.,
Schwede Donna,
Murphy Ben,
Helmig Detlev,
Lyman Seth N.,
Roselle Shawn
Publication year - 2017
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2017jd027057
Subject(s) - weather research and forecasting model , environmental science , cmaq , ozone , atmospheric sciences , air quality index , snow , structural basin , pollutant , deposition (geology) , climatology , meteorology , geology , chemistry , geography , paleontology , organic chemistry
The Weather Research and Forecasting (WRF) and Community Multiscale Air Quality (CMAQ) models were used to simulate a 10 day high‐ozone episode observed during the 2013 Uinta Basin Winter Ozone Study (UBWOS). The baseline model had a large negative bias when compared to ozone (O 3 ) and volatile organic compound (VOC) measurements across the basin. Contrary to other wintertime Uinta Basin studies, predicted nitrogen oxides (NO x ) were typically low compared to measurements. Increases to oil and gas VOC emissions resulted in O 3 predictions closer to observations, and nighttime O 3 improved when reducing the deposition velocity for all chemical species. Vertical structures of these pollutants were similar to observations on multiple days. However, the predicted surface layer VOC mixing ratios were generally found to be underestimated during the day and overestimated at night. While temperature profiles compared well to observations, WRF was found to have a warm temperature bias and too low nighttime mixing heights. Analyses of more realistic snow heat capacity in WRF to account for the warm bias and vertical mixing resulted in improved temperature profiles, although the improved temperature profiles seldom resulted in improved O 3 profiles. While additional work is needed to investigate meteorological impacts, results suggest that the uncertainty in the oil and gas emissions contributes more to the underestimation of O 3 . Further, model adjustments based on a single site may not be suitable across all sites within the basin.