RESEARCH ARTICLE


Theoretical Investigations on Potential Impacts of High-Latitude Volcanic Emissions of Heat, Aerosols and Water Vapor and their Interactions with Clouds and Precipitation



Morgan B. Yarker1, Debasish PaiMazumder1, Catherine F. Cahill2, Jonathan Dehn3, Anupma Prakash4, Nicole Mölders*, 1
1 University of Alaska Fairbanks, Geophysical Institute & College of Natural Science and Mathematics, Department of Atmospheric Sciences, 903 Koyukuk Dr., Fairbanks, Alaska 99775, USA
2 University of Alaska Fairbanks, Geophysical Institute & Department of Chemistry and Biochemistry, 903 Koyukuk Dr.,Fairbanks, Alaska 99775, USA
3 University of Alaska Fairbanks, Geophysical Institute & Alaska Volcano Observatory, 903 Koyukuk Dr., Fairbanks, Alaska 99775, USA
4 University of Alaska Fairbanks, Geophysical Institute & Department of Geophysics, 903 Koyukuk Dr., Fairbanks, Alaska 99775, USA


© 2010 Yarkeret al.;

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: https://creativecommons.org/licenses/by/4.0/legalcode. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the University of Alaska Fairbanks, Geophysical Institute & College of Natural Science and Mathematics, Department of Atmospheric Sciences, 903 Koyukuk Dr., Fairbanks, Alaska 99775, USA; Tel: (907) 474-7910; Fax: (907) 474-7379; E-mail: molders@gi.alaska.edu


Abstract

Augustine Volcano (located in the Cook Inlet of South Central Alaska at 59.4oand 153.4oW) erupted in January 2006 and released, among other things, water vapor, radiation heat, and aerosols into the atmosphere. To determine the potential impact of volcanic emissions and ashfall on local weather, 16 simulations assuming artificial emission and ashfall scenarios were performed with the Weather Research and Forecasting model for 24 consecutive days starting the day before the first eruption. These simulations include (1) the control simulation without consideration of any volcanic perturbation, (2) four simulations with simplified scenarios for each individual volcanic factor [radiative heat from the caldera, water vapor, cloud condensation nuclei (CCN) and/or ice nuclei (IN) aerosols, and albedo change due to ashfall], and (3) 11 simulations containing all possible combinations of these factors. These 11 simulations serve to examine interactions among impacts of the different perturbations under the assumed scenarios. The impact of volcanic factors on local weather depends on the synoptic situation, emission strength, (combination of) volcanic factors, and interaction among impacts of factors if they occur concurrently. ANalysis Of VAriance shows that the greatest (statistically significant at the 95% or higher confidence level) volcanic impact occurs on relatively humid days and immediately downwind of the volcano (<50 km). Depending on relative humidity and temperature conditions, volcanic heat release can increase condensation and/or cloud top levels or reduce cloudiness. Due to non-linear cloud microphysical processes, meteorological responses to volcanic factors can diminish or enhance the impacts of the individual factors when factors occur concurrently. As an example, depending on the ambient conditions, concurrently occurring volcanic factors can lead to a decrease in precipitation at one time and an increase at another time. These findings indicate that in the immediate vicinity of erupting volcanoes, predicted cloud conditions and precipitation may be inaccurate due to the unknown volcanic forcing.

Keywords: Volcanic emissions, WRF, ANOVA, Clouds, Evaluation.