edu.ucar.opensky::articles:26514 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-24T19:27:35.856515 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7z60t35 https://doi.org/10.5065/D6RX99HX https Related Service #1 Cheyenne: SGI ICE XA Cluster Quantifying the efficiency of stratospheric aerosol geoengineering at different altitudes 2023-07-28T00:00:00Z publication https://n2t.org/ark:/85065/d7z60t35 https://doi.org/10.1029/2023GL104417 Lee, W. R. author Visioni, Daniele author Bednarz, E. M. author MacMartin, D. G. author Kravitz, B. author Tilmes, Simone author UCAR/NCAR - Library publisher Stratospheric aerosol injection (SAI) of reflective sulfate aerosols has been proposed to temporarily reduce the impacts of global warming. In this study, we compare two SAI simulations which inject at different altitudes to provide the same amount of cooling, finding that lower-altitude SAI requires 64% more injection. SAI at higher altitudes cools the surface more efficiently per unit injection than lower-altitude SAI through two primary mechanisms: the longer lifetimes of SO2 and SO4 at higher altitudes, and the water vapor feedback, in which lower-altitude SAI causes more heating in the tropical cold point tropopause region, thereby increasing water vapor transport into the stratosphere and trapping more terrestrial infrared radiation that offsets some of the direct aerosol-induced cooling. We isolate these individual mechanisms and find that the contribution of lifetime effects to differences in cooling efficiency is approximately five to six times larger than the contribution of the water vapor feedback. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright author(s). This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. None eng geoscientificInformation