Contributions From Cloud Morphological Changes to the Interannual Shortwave Cloud Feedback Based on MODIS and ISCCP Satellite Observations

• Published in: Journal of Geophysical Research: Atmospheres
• Main Authors: Tan, Ivy, Zelinka, Mark D., Coopman, Quentin, Kahn, Brian H., Oreopoulos, Lazaros, Tselioudis, George, Mccoy, Daniel T., Li, Ninghui
• Other Authors: McGill University = Université McGill Montréal, Canada, Lawrence Livermore National Laboratory (LLNL), Laboratoire d’Optique Atmosphérique - UMR 8518 (LOA), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), NASA Goddard Space Flight Center (GSFC), NASA Goddard Institute for Space Studies (GISS), University of Wyoming (UW)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2024
• Subjects: climate; cloud feedback; Southern Ocean; MODIS; ISCCP; morphology; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere
• Online Access: https://hal.univ-lille.fr/hal-04601781; https://hal.univ-lille.fr/hal-04601781/document; https://hal.univ-lille.fr/hal-04601781/file/JGR%20Atmospheres%20-%202024%20-%20Tan%20-%20Contributions%20From%20Cloud%20Morphological%20Changes%20to%20the%20Interannual%20Shortwave%20Cloud%20Feedback.pdf; https://doi.org/10.1029/2023JD040540

International audience The surface temperature-mediated change in cloud properties, referred to as the cloud feedback, continues to dominate the uncertainty in climate projections. A larger number of contemporary global climate models (GCMs) project a higher degree of warming than the previous generation of GCMs. This greater projected warming has been attributed to a less negative cloud feedback in the Southern Ocean. Here, we apply a novel “double decomposition method” that employs the “cloud radiative kernel” and “cloud regime” concepts, to two data sets of satellite observations to decompose the interannual cloud feedback into contributions arising from changes within and shifts between cloud morphologies. Our results show that contributions from the latter to the cloud feedback are large for certain regimes. We then focus on interpreting how both changes within and between cloud morphologies impact the shortwave cloud optical depth feedback over the Southern Ocean in light of additional observations. Results from the former cloud morphological changes reveal the importance of the wind response to warming increases low- and mid-level cloud optical thickness in the same region. Results from the latter cloud morphological changes reveal that a general shift from thick storm-track clouds to thinner oceanic low-level clouds contributes to a positive feedback over the Southern Ocean that is offset by shifts from thinner broken clouds to thicker mid- and low-level clouds. Our novel analysis can be applied to evaluate GCMs and potentially diagnose shortcomings pertaining to their physical parameterizations of particular cloud morphologies.