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 Cristobal and Masaya, Nicaragua; Arenal and Poas, 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 center dot d(-1) from Tungurahua in July 2006, 2375 t center dot d(-1) in September 2005 and 480 t center dot d(-1) in February 2006 from Santa Ana, 1200 t center dot d(-1) in May 2005 from Etna, 955 t center dot d(-1) in March 2006 and 1165 t center dot d(-1) in December 2006 from Masaya, 5400 t center dot d(-1) of March 7, 2006 and 265 t center dot d(-1) in March 2006 from San Cristobal, 113 t center dot d(-1) in April 2006 from Arenal, 104 t center dot d(-1) in April 2006 from Poas and 11 t center dot 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%.