SO2 Emission from Active Volcanoes Measured Simultaneously by COSPEC and mini-DOAS

We measured SO2 emission rate from six volcanoes in Latin America (Santa Ana, El Salvador; San Cristo´bal and Masaya, Nicaragua; Arenal and Poa´s, Costa Rica; Tungurahua and Sierra Negra, Ecuador) and from Mt. Etna, Italy, using two different remote sensing techniques: COSPEC (COrrelation SPECtrometer) and miniDOAS (miniaturized Differential Optical Absorption Spectroscopy). One of the goals of this study was to evaluate the differences in SO2 emission rates obtained by these two methods. The observed average SO2 emission rates measured during this study were 2688 t d-1 from Tungurahua in July 2006, 2375 t d-1 in September 2005 and 480 t d-1 in February 2006 from Santa Ana, 1200 t d-1 in May 2005 from Etna, 955 t d-1 in March 2006 and 1165 t d-1 in December 2006 from Masaya, 5400 t d-1 of March 7, 2006 and 265 t d-1 in March 2006 from San Cristobal, 113 t d-1 in April 2006 from Arenal, 104 t d-1 in April 2006 from Poa´s and 11 t d-1 in July 2006 from Sierra Negra volcano. Most of the observed relative differences of SO2 emission measurements from COSPEC and miniDOAS were lower than 10%.