Persistent after-effects of heavy rain on concentrations of ice nuclei and rainfall suggest a biological cause Atmospheric Chemistry and Physics DOI 10.5194/acp-15-2313-2015 3 March 2015 We show that atmospheric load of ice nuclei is enhanced for up to 20 days after key rainfall events. The rate of enhancement decreases exponentially with time. Rainfall quantity and frequency are increased for a similar duration and with similar exponential decreases thereby supporting the notion of rainfall feedback. We reveal series of significant feedback in rainfall patterns across Australia over the past century and marked changes in feedback patterns, and we indicate their locations. Read more
Identification and quantification of gaseous organic compounds emitted from biomass burning using two-dimensional gas chromatography–time-of-flight mass spectrometry Atmospheric Chemistry and Physics DOI 10.5194/acp-15-1865-2015 23 February 2015 This work represents the first application of two-dimensional gas chromatography to broadly characterize the gas-phase emissions of biomass burning, including comparisons among the emissions from burns of selected conifer, grass, crop residue, and peat fuel types. In these smoke samples, over 700 compounds were detected, which are discussed in the context of potential secondary organic aerosol formation. Read more
Seasonal in situ observations of glyoxal and methylglyoxal over the temperate oceans of the Southern Hemisphere Atmospheric Chemistry and Physics DOI 10.5194/acp-15-223-2015 12 January 2015 Glyoxal and methylglyoxal are short-lived organic trace gases and important precursors of secondary organic aerosol. Measurements over oceans are sparse. We present the first in situ glyoxal and methylglyoxal observations over remote temperate oceans, alongside observations of precursor gases. Precursor gases cannot explain observed mixing ratios, highlighting an unknown source. We show a large discrepancy between calculated vertical column densities of glyoxal and those retrieved by satellite. Read more
Potential climate forcing of land use and land cover change Atmospheric Chemistry and Physics DOI 10.5194/acp-14-12701-2014 3 December 2014 While climate change mitigation policy often focuses on the energy sector, we find that 40% of the historical human-caused change in the Earth’s radiative balance can be attributed to land use activities, such as deforestation and agriculture. Since pressure on land resources is expected to increase, we compute a theoretical upper bound on the radiative balance impacts from future land use which suggests that not only energy policy but land policy is necessary to minimize future climate change. Read more
Missing SO2 oxidant in the coastal atmosphere? – observations from high-resolution measurements of OH and atmospheric sulfur compounds Atmospheric Chemistry and Physics DOI 10.5194/acp-14-12209-2014 20 November 2014 Sulfuric acid plays a major role in the formation of aerosol particles and clouds. Measurements at the west coast of Ireland reveal that oxidation of SO2 by OH explains only 20%, on average, of H2SO4 formation in coastal marine air. Additional sources may be oxidation by Criegee intermediates produced photolytically and/or formation from SO3 instead of SO2 in the oxidation of dimethyl sulfide suggesting an important role of marine emissions in the self-cleaning power of the atmosphere. Read more
Mapping the physico-chemical properties of mineral dust in western Africa: mineralogical composition Atmospheric Chemistry and Physics DOI 10.5194/acp-14-10663-2014 10 October 2014 In the last few years, several ground-based and airborne field campaigns have allowed the exploration of the properties and impacts of mineral dust in western Africa. This paper explores the synthesis of these observations to provide a large-scale quantitative view of the mineralogical composition and its variability according to source region and time after transport. Read more
Constraining CO2 emissions from open biomass burning by satellite observations of co-emitted species: a method and its application to wildfires in Siberia Atmospheric Chemistry and Physics DOI 10.5194/acp-14-10383-2014 1 October 2014 A method to constrain carbon dioxide (CO2) emissions from open biomass burning by using satellite observations of co-emitted species and a chemistry-transport model (CTM) is proposed and applied to the case of wildfires in Siberia. Read more
Tropospheric ozone increases over the southern Africa region: bellwether for rapid growth in Southern Hemisphere pollution? Atmospheric Chemistry and Physics DOI 10.5194/acp-14-9855-2014 17 September 2014 Increases in tropospheric ozone based on ozonesonde records (early 1990s to 2008) over subtropical stations in Irene (South Africa) and Réunion have been reported. Over Irene a large increase in the urban-influenced boundary layer (BL) was also observed. This paper shows that the Irene BL trend is at least partly due to a gradual change in the sonde launch times. Read more
Molecular corridors and kinetic regimes in the multiphase chemical evolution of secondary organic aerosol Atmospheric Chemistry and Physics DOI 10.5194/acp-14-8323-2014 20 August 2014 Based on molecular identification of secondary organic aerosol (SOA) oxidation products, the authors show here that the chemical evolution of SOA from a variety of volatile organic compound precursors adheres to characteristic “molecular corridors” with a tight inverse correlation between volatility and molar mass. Read more
Quantification of ice nuclei active at near 0 °C temperatures in low-altitude clouds at the Puy de Dôme atmospheric station Atmospheric Chemistry and Physics DOI 10.5194/acp-14-8185-2014 14 August 2014 In this study, cloud water was collected aseptically from the summit of Puy de Dôme (1465 m a.s.l., France) within contrasted meteorological and physico-chemical situations. Total and biological (i.e. heat-sensitive) IN were quantified by droplet-freezing assay between −5 °C and −14 °C. Read more
