Silent degassing of volcanoes and the dispersal of volcanic aerosols in the atmosphere
Atmospheric dispersion and related health impacts of continuous emissions from Nicaraguan volcanoes
Volcanic emissions are an important source of atmospheric gases and aerosols. Andres and Kasgnoc (1998) determined that 99% of volcanic SO2 are being released continuously, while only 1 % is released during sporadic eruptions. However, the chemistry and climate influence of tropospheric volcanic plumes is rather poorly known.
Within this project we aim to improve the determination of the dispersion of continuous volcanic emissions into the troposphere, the chemical and aerosol microphysical modifications of the re-leased gases and aerosols, related acid deposition and impacts on the environment and human health. Nicaragua with its currently six active volcanoes (Fig. 1) (Mather et al., 2006) is chosen as study area, because of its continuous volcanic activity that is monitored by a complex geophysical network including gas emissions within the EU project NOVAC. Numerical model simulations with the regional scale atmosphere-chemistry/aerosol model REMOTE (Langmann, 2000) (http://www.mpimet.mpg.de/en/wissenschaft/modelle/remote.html) will be carried out during the dry and rainy season over Central America focusing on Nicaragua as atmospheric modeling offers a useful tool to study processes occurring in the volcanic plume or in the vicinity of active volcanoes that are difficult to measure directly.
Volcanic plume rise in the atmosphere will be considered by calculating an effective emission height of the volcanic plume into the atmosphere dependent on volcanic heat flux and meteorological conditions to investigate their importance for further dispersion of the volcanic trace species in the atmosphere. The height of volcanic plume rise into the atmosphere mainly determines how far volcanic gas and ash emissions disperse within the atmosphere and how long they re-main, thereby defining the local, regional or even global climate and environmental impacts.
References:
Andres, R. J. and A. D. Kasgnoc: A time-averaged inventory of subaerial volcanic sulphur emissions, J. Geophys. Res. 103(D19), 25251-25261, 1998.
Langmann, B., Numerical modelling of regional scale transport and photochemistry directly together with meteoro-logical processes. Atmos. Environ. 34, 3585-3598, 2000.
Mather, T. A., D. M. Pyle, V. I. Tsanev, A. J. S. McGonigle, C. Oppenheimer and A. G. Allen: A reassessment of current volcanic emissions from the Central American arc with specific examples from Nicaragua, J. Volc. Ge-otherm. Res. 149, 297-311, 2006.
Simkin, T. and I. Siebert: Smithonia Institution, Misoula, Montana, Geoscience Press, 1994.
Funding: DFG 2007-2008
Contact: Bärbel Langmann, Matthias Hort, Thor Hansteen (IFM-GEOMAR Kiel)