Convective influence on UT/LS water vapor from in-situ measurements of water vapor isotopologues

<p>The isotopic composition of water vapor provides a novel source of information on the convective origins and life cycle of water in the UT/LS region.&#160; The Chicago Water Isotope Instrument (ChiWIS) has now provided a deep catalog of measurements over both the North American and Asian summer monsoons, from both European and American high-altitude aircraft campaigns: StratoClim (Stratospheric and upper tropospheric processes for better climate predictions) in 2017, and ACCLIP (Asian summer monsoon Chemical and CLimate Impact Project in 2021-2022. Isotopic measurements show the importance of deep convection in carrying moisture as lofted ice, but also the strong distinction between the two monsoons, with higher convective influence and more complete sublimation over North America. Convective outflow remnants remain distinct for as long as two weeks and govern the locations of formations of in-situ &#8216;secondary cirrus&#8217;. We show the consistency and power of the complete dataset collected and examples highlighting the utility of isotopic measurements in understanding the life cycle of UT/LS water, including convective inputs, mixing, sedimentation, and sublimation.</p>