Rates of volcanic CO₂ degassing from airborne determinations of SO₂ Emission rates and plume CO₂SO₂: test study at Pu′u ′O′o Cone, Kilauea Volcano, Hawaii

We present an airborne method that eliminates or minimizes several disadvantages of the customary plume cross-section sampling method for determining volcanic CO₂ emission rates. A LI-COR CO₂analyzer system (LICOR), a Fourier transform infrared spectrometer system (FTIR), and a correlation spectrometer (COSPEC) were used to constrain the plume CO₂/SO₂ and the SO₂ emission rate. The method yielded a CO₂ emission rate of 300 td⁻¹ (metric tons per day) for Pu′u ′O′o cone, Kilauea volcano, on 19 September 1995. The CO₂/SO₂ of 0.20 determined from airborne LICOR and FTIR plume measurements agreed with the CO₂/SO₂ of 204 ground-based samples collected from vents over a 14-year period since the Pu′u ′O′o eruption began in January 1983.