EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Water vapor isotopic variations of the upper troposphere/ lower stratosphere in the N. American and Asian Summer Monsoons

Carly KleinStern1, Benjamin Clouser2, Thaopaul Bui3, Francesco D'Amato4, Silvia Viciani4, Giovanni Bianchini4, Troy Thornberry5, and Elisabeth Moyer2
Carly KleinStern et al.
  • 1University of Chicago, Department of Physics, Chicago, IL, United States of America (
  • 2University of Chicago, Department of Geophysical Sciences, Chicago, IL, United States of America
  • 3NASA Ames Research Center, United States of America, Moffett Field, CA, United States of America
  • 4National Institute of Optics, National Research Council (CNR-INO), Florence, Italy
  • 5Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO, United States of America

The 2022 ACCLIP (Asian summer monsoon Chemical and CLimate Impact Project) high-altitude aircraft campaign has provided a sampling of the diversity of processes that affect moisture transport in the upper troposphere / lower stratosphere (UT/LS). We report here on ACCLIP observations of water vapor isotopologues, which trace the origin and microphysical history of water vapor. Measurements with the Chicago Water Isotope Instrument (ChiWIS) show isotopic variations in the UT/LS that correlate with airmass history, and 100-150 ‰ variation even at the same water content. ACCLIP flights out of Osan, South Korea sampled monsoon anticyclone outflow with CO values over 200 ppb, recent local convection, extensive in-situ cirrus, and an overflight of tropical cyclone Hinnanmor showing strong isotopic depletion. Flights out of Houston, TX  sampled week-old remnants of sublimated ice from deep convection, producing enriched vapor, and possible mixing of convective overshoots with stratospheric air before sinking. We show through case studies from both Asia and North America that isotopologues provide a sensitive diagnostic of ice sublimation, and demonstrate how different meteorological contexts produce distinct isotopic signatures.

How to cite: KleinStern, C., Clouser, B., Bui, T., D'Amato, F., Viciani, S., Bianchini, G., Thornberry, T., and Moyer, E.: Water vapor isotopic variations of the upper troposphere/ lower stratosphere in the N. American and Asian Summer Monsoons, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-11111,, 2023.

Supplementary materials

Supplementary material file