Revisiting the Importance of Chemical Data Assimilation to Modeling East Asia Air Quality and Its Impact on Downwind Regions

In support of the NASA ARCTAS field campaign and the Task Force on Hemispheric Transport of Air Pollution multi-model experiment, satellite chemical data assimilation was implemented in multi-scale air quality modeling studies. It was concluded that chemical data assimilation improved the simulated total and background ozone (including the contribution from East Asian emissions source) over the western United States. Since then a number of updates have been included in the regional NUWRF-Chem (NASA Unified Weather Research and Forecasting model with Chemistry) air quality modeling system, which improve atmospheric weather modeling via better representing the land-atmosphere interactions. Using this NUWRF-Chem modeling system, the importance of applying satellite constrained chemical initial/boundary conditions and emission inputs to air quality modeling is evaluated during the Korea-US Air Quality Field Study over East Asia in Spring 2016. Specifically, we demonstrate the benefit of using fine-resolution (0.4 degree horizontally) Copernicus Atmosphere Monitoring Service with multi-instrument, multi-species chemical data assimilation, as well as anthropogenic NOx, VOC, and SO2 emissions constrained by the Ozone Monitoring Instrument. Additionally, the improved model chemical inputs enable more convenient investigations on land-atmosphere interactions aided by satellite land and weather products.