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Enhanced representation of inter-continental pollutant transport by assimilating satellite NO2 and performing NOx emissions inversions
Citation:
East, J., B. Henderson, S. Napelenok, S. Koplitz, R. Pierce, A. Lenzen, R. Gilliam, G. Sarwar, AND F. Garcia-Menendez. Enhanced representation of inter-continental pollutant transport by assimilating satellite NO2 and performing NOx emissions inversions. 20th CMAS Conference, Virtual, NC, November 01 - 05, 2021.
Impact/Purpose:
This research presents results of implementing NO2 data assimilation into the CMAQ model.
Description:
Long-range transport of O3 has human health and regulatory impacts in the US, and is produced in part from international NOx emissions. Accurately representing international O3 transport in hemispheric and global-scale models requires accurate emissions inventories. However, global bottom-up emissions estimates can be out-of-date and uncertain, particularly in developing countries, limiting the representation of international emissions and transport in models. We introduce a satellite data assimilation system for inverse modeling of northern hemisphere NOx emissions which offers opportunities to improve representations of long range ozone transport and model performance. The system can provide estimates of NOx emissions in China, India, Europe, and the US. We assimilate OMI and TROPOMI separately in the CMAQ model for 2019 over the northern hemisphere and perform NOx emissions inversions for each assimilation. We analyze and compare model performance and long-range transported O3 in simulations (1) without any satellite derived information, (2) with assimilated NO2, and (3) with satellite derived emissions updates. Results show large NOx emissions biases in India and China, and smaller biases in the US and Europe compared to satellite-inferred estimates. Assimilating NO2 and using satellite-inferred emissions improves O3 and NOx model performance.