Homeyer, Cameron R.Smith, Jessica B.Bedka, Kristopher M.Bowman, Kenneth P.Wilmouth, David M.Ueyama, ReiDean-Day, Jonathan M.Clair, Jason St.Hannun, ReemHare, JenniferPandey, ApoorvaSayres, David S.Hanisco, Thomas F.Gordon, Andrea E.Tinney, Emily N.2023-10-172023-10-172023-09-26Homeyer, C. R., Smith, J. B., Bedka, K. M., Bowman, K. P., Wilmouth, D. M., Ueyama, R., et al. (2023). Extreme altitudes of stratospheric hydration by midlatitude convection observed during the DCOTSS field campaign. Geophysical Research Letters, 50, e2023GL104914. https://doi.org/10.1029/2023GL104914https://doi.org/10.1029/2023GL104914http://hdl.handle.net/11603/30231Water vapor's contribution to Earth's radiative forcing is most sensitive to changes in its lower stratosphere concentration. One recognized pathway for rapid increases in stratospheric water vapor is tropopause-overshooting convection. Since this pathway has been rarely sampled, the NASA Dynamics and Chemistry of the Summer Stratosphere (DCOTSS) field project focused on obtaining in situ observations of stratospheric air recently affected by convection over the United States. This study reports on the extreme altitudes to which convective hydration was observed. The data show that the overworld stratosphere is routinely hydrated by convection and that past documented records of stratospheric heights of convective hydration were exceeded during several DCOTSS flights. The most extreme event sampled is highlighted, for which stratospheric water vapor was increased by up to 26% at an altitude of 19.25 km, a potential temperature of 463 K, and an ozone mixing ratio >1500 ppbv.9 pagesen-USThis work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.Public Domain Mark 1.0http://creativecommons.org/publicdomain/mark/1.0/Text