Open AccessEstimating US Background Ozone Using Data Fusion
Author(s) -
T. Nash Skipper,
Yongtao Hu,
M. Talat Odman,
B. H. Henderson,
Christian Hogrefe,
Rohit Mathur,
Armistead G. Russell
Publication year - 2021
Publication title -
environmental science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.851
H-Index - 397
eISSN - 1520-5851
pISSN - 0013-936X
DOI - 10.1021/acs.est.0c08625
Subject(s) - cmaq , ranging , ozone , environmental science , atmospheric sciences , statistics , meteorology , climatology , mathematics , geography , physics , geodesy , geology
US background (US-B) ozone (O 3 ) is the O 3 that would be present in the absence of US anthropogenic (US-A) emissions. US-B O 3 varies by location and season and can make up a large, sometimes dominant, portion of total O 3 . Typically, US-B O 3 is quantified using a chemical transport model (CTM) though results are uncertain due to potential errors in model process descriptions and inputs, and there are significant differences in various model estimates of US-B O 3 . We develop and apply a method to fuse observed O 3 with US-B O 3 simulated by a regional CTM (CMAQ). We apportion the model bias as a function of space and time to US-B and US-A O 3 . Trends in O 3 bias are explored across different simulation years and varying model scales. We found that the CTM US-B O 3 estimate was typically biased low in spring and high in fall across years (2016-2017) and model scales. US-A O 3 was biased high on average, with bias increasing for coarser resolution simulations. With the application of our data fusion bias adjustment method, we estimate a 28% improvement in the agreement of adjusted US-B O 3 . Across the four estimates, we found annual mean CTM-simulated US-B O 3 ranging from 30 to 37 ppb with the spring mean ranging from 32 to 39 ppb. After applying the bias adjustment, we found annual mean US-B O 3 ranging from 32 to 33 ppb with the spring mean ranging from 37 to 39 ppb.