This work addresses the relationship between major dynamical forcings and variability in NO column measurements. The dominating impact on Siberia is due to El Niño, on Indonesia, Northern Australia and South America is due to IOD,and on the remaining regions is due to NAO. That NO pollution in Indonesia is modulated by IOD contradicts previous work using AOD and El Niño. Simultaneous impacts of present and lagged forcings are derived using multi-linear regression, demonstrating El Niño impacts NO variability from 7 to 98 weeks ahead, while IOD and NAO are mostly impacted by past changes in NO variability. In all cases, lagged forcings exhibit more impact than present forcings, hinting at non-linearity. Finally, dynamical forcings are responsible for over 50% of the NO variability in most non-urban areas and over 40% in urban Indonesia and China. These results demonstrate the significance of climate forcing on short-lived air pollutants.

The contribution of biomass burning to the total aerosol loading over Monsoon Asia is both significant while also continuing to increase in recent decades. To better match the spatio-temporal distribution of aerosols and trace gasses observed in the free troposphere, this work applied a 3-D constrained emission inventory based on top-down remotely sensed NO2 measurement to investigate the most extreme of the annually occurring biomass burning seasons in Monsoon Asia. In 2016 this constituted an extreme event observed over a 6-day period covering millions of square kilometers, including over regions which are typically in the rainy phase of the Monsoon at this time. The results are shown to be consistent with respect to TRMM precipitation, AERONET measurements, MODIS AOD, MOPITT CO, and reanalysis meteorology, over both the biomass burning source as well as the millions of square kilometers downwind both to the East and to the Southwest. Reproducing the observed long-range transport pattern requires the time of biomass burning to be increased, regions not previously identified as burning to be actual source regions, and the emissions of BC to be 6.6 to 11.9 time larger than current inventories. The underlying mechanism for this long-range transport involves a new 3-D pathway that can occur during the transition from the North to the South Monsoon. The results are also consistent with the new idea that large loadings of BC in the lower free troposphere may significantly affect the meteorological field and the overall vertical distribution of aerosols in the tropical troposphere.

Absorbing aerosols uniquely impact radiative forcing, aerosol chemical transport, and meteorology. This paper uniquely quantifies BC core and sulfate shell size and mass using decadal measurements of multi-spectral AOD, SSA, and AE from AERONET stations located throughout East, Southeast, and South Asia, in connection with a MIE model. All sites are uniquely characterized into four types: urban, biomass burning, long-range transport, and clean. The size and mass of the core and shell are calculated as probability distributions, and found to be unique within each classification. Well known urban, biomass burning, and clean sites are all properly identified. Furthermore, two unique sites previously thought to not have multiple characteristics are identified, with urban and biomass burning significant in Beijing and long-range transport significant in the otherwise clean South China Sea at Taiping island. It is hoped that these results will allow for advances in attribution and radiative forcing studies.