Characterizing Intraseasonal and Interannual Variability in the Composition of the Asian Summer Monsoon Anticyclone using Aura Microwave Limb Sounder Measurements (Invited Presentation)

The Aura Microwave Limb Sounder (MLS), launched in July 2004, makes simultaneous co-located measurements of trace gases and cloud ice water content (a proxy for deep convection) in the upper troposphere / lower stratosphere (UTLS) on a daily basis. With its dense spatial and temporal sampling, extensive measurement suite, and insensitivity to aerosol and all but the thickest clouds, Aura MLS is well suited to characterizing UTLS composition in the region of the Asian summer monsoon (ASM) and quantifying the considerable spatial and seasonal variations therein. In addition, the 20-year MLS data record is invaluable for assessing interannual variability in the impact of the ASM on the UTLS. In this talk we will examine MLS measurements of cloud ice and both tropospheric (CO, CH₃Cl, CH₃CN, HCN) and stratospheric (O₃, HNO₃, HCl) tracers, along with meteorological reanalyses, to place the 2017 and 2022 ASM seasons observed in detail by the StratoClim and ACCLIP field campaigns, respectively, into the spatial and temporal context of other monsoons in the last two decades.