Composition of the Asian Summer Monsoon: Climatology and variability from 10 years of Aura MLS measurements

The Asian summer monsoon (ASM) is the dominant climatological feature of the circulation in the upper troposphere / lower stratosphere (UTLS) during boreal summer and thus has a strong impact on global climate. Here we use the 10-year data record from NASA's Aura Microwave Limb Sounder (MLS) to investigate the composition of the ASM region. MLS makes daily global simultaneous co-located measurements of an extensive suite of trace gases and cloud ice. We characterize the climatology of and quantify the spatial, seasonal, and interannual variations in multiple species of both tropospheric and stratospheric origin in the ASM region. We also relate the observed trace gas behavior to various meteorological quantities, such as the size and strength of the ASM anticyclone, the extent and intensity of deep convection, and variations in the tropopause and the upper tropospheric jets in that region. Use of multiple trace gases is valuable for assessing whether variability arises from transport processes or differences in sources regions.