CALCULATION OF SO2 FLUXES FROM ACTIVE VOLCANOES IN EL SALVADOR AND NICARAGUA, USING OMI IMAGES

Satellite images from the Ozone Monitoring Instrument (OMI) were downloaded and processed in order to measure the SO₂ mass in plumes and then calculate the flux of SO₂ produced by the most active volcanoes in El Salvador (Santa Ana and San Miguel) and Nicaragua (San Cristóbal, Masaya, Concepción, and Telica) in the period of 2005-2012. I discuss here the degassing activity of each volcano studied based on the OMI results and on ground-based data, which were compared with the volcanic activity in the period. Trajectory models from the Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT) were used to determine the altitudes of the volcanic plumes. Sounding data were used to determine the wind speed at the respective plume heights. Based on the 25 OMI images processed and analyzed using the “smoke estimation technique” developed by Ichoku and Kaufman (2005), the average SO₂ flux for El Salvador was 530 t/d and for Nicaragua it was 610 t/d, for the period 2007-2012. Santa Ana had the highest degassing event, with an SO₂ flux of ~19 kilotons per day on October 2005, during its most recent eruption. The highest emitter for Nicaragua was Masaya volcano, with an average SO₂ flux of 650 t/d during the 2007-2012 period. The annual contribution of the studied volcanoes in El Salvador and Nicaragua during the 2007-2012 period of time to the global sulfur budget is ~0.50 teragrams per year, which represents ~2-5% of the global volcanic sulfur budget.