Tropopause‐Level NO(x) in the Asian Summer Monsoon

Deep convection within the Asian summer monsoon (ASM) transports surface level air into the upper troposphere‐lower stratosphere (UTLS). This work aims to understand the distribution of NO(2), NO, and NO(x) in the UTLS ASM anticyclone from satellite measurements. Observations of NO(2) from the Optical Spectrograph and InfraRed Imager System, the Atmospheric Chemistry Experiment ‐ Fourier Transform Spectrometer (ACE‐FTS), and the Stratospheric Aerosol and Gas Experiment III on the International Space Station are considered. The PRATMO photochemical box model is used to quantify the NO(x) photochemistry, and to derive the NO(x) concentration using OSIRIS NO(2) and O(3) observations. The satellite data show a relative minimum in NO(2) over the ASM in the summer months, while the corresponding NO and NO(x) anomalies are elevated, mainly due to low O(3) and cold temperatures within the ASM. The observations within the ASM show reasonable agreement to simulations from the Whole Atmosphere Community Climate Model.