Tropospheric O3 modeling study: Contributions of anthropogenic and biogenic sources to O3-CO and O3-CH2O correlations

Ye Cheng
Friday, October 27, 2017 - 10:00am
ES&T Room L1120
Dr. Yuhang Wang, Dr. Rodeny Weber, Dr. Yi Deng, Dr. Nga Lee and Dr. James H. Crawford (NASA Langley Research Center)

This dissertation employs DISCOVER-AQ aircraft experiments and 3-D chemical and transport model to study the contributions of different sources to the  correlation of O3-CO and O3-CH2O on different scales, and the implements of O3 estimation using the correlations and concentrations of CO and CH2O.

First, modeling analysis suggests that the contribution from biogenic isoprene  oxidation to the observed O3-CO regression slope is as large as that from primary anthropogenic CO emissions in the eastern US. As a result of decrease of anthropogenic primary CO emissions during the past decades, observed and simulated O3-CO regression slopes can no longer be used directly with an anthropogenic CO emission inventory to quantify anthropogenic O3 production over the United States. The proportion of contribution from biogenic isoprene to the regressed O3-CO slopes various depending on the corresponding local emission scenario. While biogenic isoprene oxidation makes a comparable contribution as anthropogenic emissions in the eastern US, the latter dominates over eastern China. Second, making use of these linear dependence, we build a fast-response ozone estimator using near surface CH2O and CO concentrations as inputs. We examine the quality of this O3 estimator by increasing or decreasing anthropogenic emissions by up to 50% and the estimated O3 distribution is in reasonably good agreement with the full-model simulations.

Finally, we focus on regional anthropogenic O3 precursor emissions. Sensitivity simulations of aircraft and surface in situ observations suggest an increase of alkane emissions by a factor of 15 to the alkanes emissions in the Houston Ship Channel, where ship-transmit, ship-unloading, storage, domestic transportation of oil take place, and a factor of 5 to alkanes emissions in Denver area.