87:6672 Volcanoes and extinctions: round two: Weisburd, S., 1987. Sci. News, Washington, D.C., 131(16):248–250

In this thesis, the vertical distribution of atmospheric trace gases and aerosols were retrieved using Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS). Various inversion methods were used to retrieve the profiles from the MAX-DOAS measurements. A new MAX-DOAS instrument optimized for the measurement of aerosol and trace gas profiles was developed. The retrieval methods were tested and advanced in the scope of the EUSAAR (European Supersites for Atmospheric Aerosol Research) project. Several intercomparison campaigns were carried out in Cabauw (the Netherlands), Ispra (Italy) and Leipzig/Melpitz (Germany). Aerosol extinction and NO2 profiles were retrieved from the MAX-DOAS measurements and compared to independent in situ and remote sensing measurements. Good agreements were achieved for both the aerosol and NO2 profiles. Furthermore, the diluted plume of the Eyjafjallajokull volcano, Iceland, was detected by MAX-DOAS SO2 measurements over Heidelberg in April and May 2010. These measurements showed an unambiguous detection of SO2, and are in agreement with satellite observations and model predictions. The here presented advances in instrumental hardware and retrieval algorithms demonstrate that MAX-DOAS is a powerful tool for monitoring the vertical distribution of atmospheric constituents. Verified by independent measurements, its integration in worldwide measurement networks is recommended.

Abstract. A regional climate model has been used to study the transport and deposition of sulfur (SO2 and SO42-) and PbCl2 emissions from Indonesian volcanoes. The sensitivity of the atmospheric loss of these trace species to meteorological conditions and their solubility was examined. Two experiments were conducted: 1) volcanic sulfur released as primarily SO2 and subject to transport, deposition, and oxidation to SO42-; and 2) PbCl2 released as an infinitely soluble passive tracer subject to only transport and deposition. The first experiment was used to calculate SO2 loss rates from each active Indonesian volcano producing an annual mean loss rate for all volcanoes of 1.1×10-5 s-1, or an e-folding rate of approximately 1 day. SO2 loss rate was found to vary seasonally, be poorly correlated with wind speed, and uncorrelated with temperature or relative humidity. The variability of SO2 loss rates is found to be correlated with the variability of wind speeds, suggesting that it is much more difficult to establish a "typical'' SO2 loss rate for volcanoes that are exposed to changeable winds. Within an average distance of 70 km away from the active Indonesian volcanoes, 53% of SO2 loss is due to conversion to SO42-, 42% due to dry deposition, and 5% due to lateral transport away from the dominant direction of plume travel. The solubility of volcanic emissions in water is shown to influence their atmospheric transport and deposition. High concentrations of PbCl2 are predicted to be deposited near to the volcanoes while volcanic S travels further away until removal from the atmosphere primarily via the wet deposition of H2SO4. The ratio of the concentration of PbCl2 to SO2 is found to exponentially decay at increasing distance from the volcanoes. The more rapid removal of highly soluble species should be considered when observing SO2 in an aged plume and relating this concentration to other volcanic species. An assumption that the ratio between the concentrations of highly soluble volcanic compounds and SO2 within a plume is equal to that observed in fumarolic gases is reasonable at small distances from the volcanic vent, but will result in an underestimation of the emission flux of highly soluble species.

Take a globe-circling tour of our endangered planet with conservation biologist Stuart Pimm - who is taking stock and keeping score. We use 50 per cent of the world's freshwater supply. We consume 42 per cent of the world's plant growth. We are liquidating animals and plants 100 times faster than the natural rate of extinction. Such numbers should make it clear that the human impact on our planet has been, and continues to be, extreme and detrimental. Yet even after decades of awareness of our environmental peril, there remains passionate disagreement over what the problems are and how they should be remedied. Much of the impasse stems from the fact that the problems are difficult to quantify. How do we assess the impact of habitat loss on various species, when we haven't even counted them all?And just what factors go into that 42 per cent of biomass we are hungrily consuming? It is only through an understanding of the numbers that we will be able to break that impasse and come to agreement. Working on the front lines of conservation biology, Stuart Pimm is one of the pioneers whose work has put the 'science' in environmental science. In this book, he appoints himself 'investment banker of the global, biological accounts', checking the numbers gathered by tireless scientists in work that is always painstaking and often heartbreaking. Pimm explains the numerical results in lucid prose. With wit, passion, and candor, he reveals the importance of understanding where those numbers come from and what they mean. To do so, he takes the reader on a globe-circling tour of our beautiful, but weary, planet. With Pimm as our indomitable guide, we travel from the volcanic mountains and rainforests of Hawaii to the boreal forests of Siberia. We see a blue whale off the Pacific coast of Mexico, where the blue oceans are slowly turning to barren deserts.We go birdwatching high up in the leafy canopy of the Amazon, from which we can see the hundreds of smoke plumes busily working at deforestation. At times, the view looks rather grim. But Pimm is no Cassandra; he never preaches or scolds. Ever optimistic, this book presents a world filled with mysterious beauty, the infinite variety of nature, and an urgent hope that through an understanding of our planet's environmental past and present, we will be inspired to save it from future extinction. '[T]his book is unashamedly optimistic. It is a celebration of our spectacular and fascinating world. I have made no attempt to restrain my joy as I encounter its natural history and its peoples. By the time you read the epilogue you will know that our world is not doomed, it is not fatally wounded, but neither is it healthy. It needs attention...' - Stuart Pimm, from the Prologue.