GISS Lunch Seminar
Speaker: Yuxuan Wang (Univ. Houston)
Title: Drought impact on atmospheric composition and its climate feedbacks

Abstract:
Drought is a recurring extreme of the climate system. The strong perturbation of drought to the land biosphere and atmospheric water cycle will influence atmospheric composition, the nature and extent of which are not well understood. In this talk, I will first present observational evidence that air pollution is significantly correlated with drought severity. The pollutant enhancements associated with droughts do not appear to be affected by the decreasing trend of US anthropogenic emissions, indicating natural processes as the primary cause. I will then use the observed drought-pollutant relationships as a diagnostic to evaluate the predictive ability of climate-chemistry models and chemical transport models and this evaluation will provide insights on the missing processes and knowledge gaps in our understanding of the feedback loops between drought and atmospheric composition. Finally, I will apply the observed relationships between drought and air pollutants to climate model projected drought occurrences and estimate a significant worsening of air quality in the US by 2100 compared to the 2000s due to increasing drought alone. Drought thus poses an important aspect of climate change penalty on air quality, and a better prediction of such effects would require improvements in model processes.