edu.ucar.opensky::articles:22877 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-25T15:26:44.992767 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7j969hx Contributions of aerosol-cloud interactions to mid-Piacenzian seasonally sea ice-free Arctic Ocean 2019-08-28T00:00:00Z publication https://n2t.org/ark:/85065/d7j969hx https://doi.org/10.1029/2019GL083960 Feng, Ran author Otto-Bliesner, Bette author Xu, Y. author Brady, Esther C. author Fletcher, T. author Ballantyne, A. author UCAR/NCAR - Library publisher Forcings and feedbacks controlling the seasonally sea ice-free Arctic Ocean during the mid-Piacenzian Warm period (3.264–3.025 Ma, MPWP), a period when CO2 level, geography, and topography were similar to present day, remain unclear given that many complex Earth System Models with comparatively higher skills at simulating twentieth century Arctic sea ice tend to produce perennial Arctic sea ice for this period. We demonstrate that explicitly simulating aerosol-cloud interactions and the exclusion of industrial pollutants from model forcing conditions is key to simulating seasonally sea ice-free Arctic Ocean of MPWP. The absence of industrial pollutants leads to fewer and larger cloud droplets over the high-latitude Northern Europe and North Pacific, which allows greater absorption of solar radiation at the surface during the early summer. This enhanced absorption triggers the seasonally runaway sea ice surface albedo feedback that gives rise to September sea ice-free Arctic Ocean and strongly amplified northern high-latitude surface warmth. 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 2019 American Geophysical Union. None eng geoscientificInformation