First synoptic analysis of volcanic degassing in Papua New Guinea

We report the first satellite-based survey of volcanic sulphur dioxide (SO \u3c inf\u3e 2 ) degassing in Papua New Guinea, using Ozone Monitoring Instrument (OMI) data. OMI is sensitive to low-level passive degassing. These observations are useful for volcano monitoring, hazard assessment (particularly aviation hazard) and assessment of arc geochemical budgets and are of immense value in remote regions with little ground-based instrumentation, such as Papua New Guinea. We identify Bagana, Manam, Rabaul, Ulawun and Langila as the active sources of volcanic SO \u3c inf\u3e 2 in Papua New Guinea, with Bagana being the largest source. We present an OMI SO \u3c inf\u3e 2 time series for 2005-2008 and a total detected regional output of ∼1.8 × 10 \u3c sup\u3e 9 kg SO \u3c inf\u3e 2 . About 40% of emissions were released by major eruption events at Manam (January 2005), Bagana (June 2006) and Rabaul (October 2006). Over the past century however, we estimate that major explosive eruptions contribute \u3c 5% of the arc-scale SO \u3c inf\u3e 2 emission budget. Ground-based DOAS measurements of SO \u3c inf\u3e 2 degassing at five of Papua New Guinea\u27s volcanoes are compared with our OMI observations. The total OMI SO \u3c inf\u3e 2 output is only ∼20% of the total extrapolated from DOAS, a discrepancy which we demonstrate is consistent with other volcanic arcs. Therefore, the true total regional SO \u3c inf\u3e 2 output may be considerably higher than that detected by OMI. Uncertainties in the OMI SO \u3c inf\u3e 2 data include the effects of in-plume chemical processing and dilution of SO \u3c inf\u3e 2 prior to the satellite overpass, OMI\u27s reduced sensitivity to low levels of SO \u3c inf\u3e 2 in the planetary boundary layer and interference by meteorological clouds. Copyright © 2012 by the American Geophysical Union