Inside the Asian Summer Monsoon: in situ observations from within deep convective clouds

The Asian summer monsoon (ASM) anticyclone is the largest circulatory system in the northern hemisphere. Deep convective systems develop in the ASM, providing fast pathways to (re)distribute aerosols, trace gases, and water vapour throughout the troposphere, eventually even overshooting into the stratosphere. Here, we will present unique in situ observations from within deep convective clouds, obtained during the StratoClim campaign (over Nepal) during the ASM in 2017, that employed the high altitude aircraft Geophysica (max. ceiling 21km). The Geophysica was carrying a set of in situ cloud microphysical instrumentation (scattering and optical array probes, and a back scatter sonde), as well as a miniature lidar for observing clouds in the vicinity of the aircraft. Additionally, instrumentation for trace gas observations were onboard.

We will present the general vertical microphysical structure of the probed clouds, by means of ice water content, mean particle sizes and numbers, and size distributions. Furthermore, trace gas measurements are used to identify up- and downdrafts in the clouds, to enable comparison of cloud microphysical properties in updrafts and downdrafts. The high altitude measurements were able to provide observations from within convective overshoots reaching into the stratosphere (above roughly 17.7km). Very large cloud particles of up to 900µm in diameter were observed in those overshoots. We will compare these rare data with similar observations from other tropical regions.