The Impact of Tropical Cyclones on Atmospheric Chemistry Using WRF-Chem and Satellite Observations

This paper focuses on the transport by tropical cyclones (TCs) of chemical species to the upper troposphere/lower stratosphere (UTLS). Species such as ozone, nitrogen oxide, carbon monoxide, etc. exert a greater influence on climate change at these high altitudes than if remaining near the surface. To our knowledge no previous research has quantified the degree to which TCs pump trace gases into the UTLS via their organized convection. We re-examine Super Typhoon Mireille (1991) in the western North Pacific (WNP) basin using in situ aircraft-derived chemical data from NASA's Pacific exploratory mission-west a (PEM-West A) field project, satellite-derived products, and high-resolution chemical transport modeling. More recent TCs in the WNP basin also are examined. We use the Weather Research and Forecasting (WRF) model with chemistry (WRF-Chem) at an innermost grid spacing of 3 km to explicitly resolve the convection being studied. Initial conditions and boundary values are from MOZART-4 (chemistry) and ERA-Interim (meteorology) datasets. The transport of various chemical species will be compared among the different TCs, as well as between their different locations of landfall. The results will help improve our understanding of how TCs affect UTLS chemistry, which can be used by the climate modeling community. Improved understanding of atmospheric chemistry in the WNP basin is important, especially in the context of increasing Asian emissions and a changing climate. Furthermore, since it has been hypothesized that global warming will lead to more intense storms, it is important to understand their role in chemical transport.