edu.ucar.opensky::articles:12666 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-26T03:48:29.714456 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d76t0nhv Microphysical simulations of large volcanic eruptions: Pinatubo and Toba 2013-02-27T00:00:00Z publication https://n2t.org/ark:/85065/d76t0nhv https://doi.org/10.1002/jgrd.50196 English, Jason author Toon, O. author Mills, Michael J. author UCAR/NCAR - Library publisher Simulations of stratospheric clouds from eruptions ranging in size from the 1991 eruption of Mount Pinatubo to that of Toba 74,000 years ago have been completed using a 3D microphysical sectional aerosol model advectively coupled to a general circulation model with prognostic chemistry (Whole Atmosphere Community Climate Model/Community Aerosol and Radiation Model for Atmospheres). For Pinatubo, properties of the aerosol cloud peak within the ranges derived from observations in the Northern Hemisphere, but reduce faster than observed, and a general low bias is found in the Southern Hemisphere. These biases could be reduced by adding aerosol radiative coupling, a quasi-biennial oscillation, and the Cerro Hudson eruption to the model. Simulations of eruptions 10 times and 100 times larger than Pinatubo suggest burdens and Aerosol Optical Depth increase less than linearly (a 100-fold injection increase produces a 20-fold AOD increase) due to particle growth and sedimentation, consistent with previous work that also found the radiative forcings from large eruptions to be self-limiting. Global-averaged AOD remains elevated for 1, 2, and 4 years, respectively, for the three simulated eruptions. The inclusion of van der Waals forces in our coagulation scheme increases peak effective radius and reduces peak AOD by about 10–20%, with bigger effects for larger eruptions. Our simulations find peak mode size to vary by up to an order of magnitude and mode width to vary by up to 50%, suggesting that two-moment modal models may not accurately capture the evolving size distribution. These simulations suggest the value of including van der Waals forces in the coagulation scheme and sectional size distributions in climate models. 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 2013 American Geophysical Union. None eng geoscientificInformation