Tropospheric ozone and its precursors from the urban to the global scale from air quality to short-lived climate forcer Atmospheric Chemistry and Physics DOI 10.5194/acp-15-8889-2015 13 August 2015 Ozone holds a certain fascination in atmospheric science. It is ubiquitous in the atmosphere, central to tropospheric oxidation chemistry, and yet harmful to human and ecosystem health as well as being an important greenhouse gas. It is not emitted into the atmosphere but is a byproduct of the very oxidation chemistry it largely initiates. This review examines current understanding of the processes regulating tropospheric ozone at global to local scales from both measurements and models. Read more
Impact of model developments on present and future simulations of permafrost in a global land-surface model The Cryosphere DOI 10.5194/tc-9-1505-2015 7 August 2015 In this paper we use a global land-surface model to study the dynamics of Arctic permafrost. We examine the impact of new and improved processes in the model, namely soil depth and resolution, organic soils, moss and the representation of snow. These improvements make the simulated soil temperatures and thaw depth significantly more realistic. Simulations under future climate scenarios show that permafrost thaws more slowly in the new model version, but still a large amount is lost by 2100. Read more
Mapping snow depth from manned aircraft on landscape scales at centimeter resolution using structure-from-motion photogrammetry The Cryosphere DOI 10.5194/tc-9-1445-2015 5 August 2015 This paper presents a photogrammetric method for measuring topography from manned aircraft with an accuracy of 30 cm and repeatability of 8 cm, at significantly lower cost than other methods. Here we created difference maps to demonstrate that we could measure snow depth with an accuracy of 10 cm compared to over 6000 snow-probe measurements on the ground, but do so over entire watersheds at 10-20 cm spatial resolution rather than just a few transects. Read more
EMPOWER-1.0: an Efficient Model of Planktonic ecOsystems WrittEn in R Geoscientific Model Development DOI 10.5194/gmd-8-2231-2015 24 July 2015 Ecosystem models provide a powerful tool for simulating ocean biology. Care must be exercised when selecting appropriate equations and parameter values to represent chosen marine ecosystems. Here, we present an efficient plankton model testbed, using simplified physics and coded in the freely available language R. Multiple runs can be undertaken for different ocean sites, permitting thorough evaluation of ecosystem model performance. The testbed also serves as an excellent resource for teaching. Read more
Evidence for biological shaping of hair ice Biogeosciences DOI 10.5194/bg-12-4261-2015 22 July 2015 We investigated an unusual ice type, called hair ice. It grows on the surface of dead wood of broad-leaf trees at temperatures slightly below 0°C.We describe this phenomenon and present our biological, physical and chemical investigations to gain insight in the properties and processes related to hair ice: we found, that a winter-acive fungus in the wood is required. Ice segregation is the common mechanism. Chemical analyses show a complex mixture of several thousand lignin/tannin compounds. Read more
Mapping gas-phase organic reactivity and concomitant secondary organic aerosol formation: chemometric dimension reduction techniques for the deconvolution of complex atmospheric data sets Atmospheric Chemistry and Physics DOI 10.5194/acp-15-8077-2015 22 July 2015 This paper describes a new ensemble methodology for the statistical analysis of atmospheric gas- & particle-phase composition data sets. The methodology reduces the huge amount of data derived from many chamber experiments to show that organic reactivity & resultant particle formation can be mapped into unique clusters in statistical space. The model generated is used to map more realistic plant mesocosm oxidation data, the projection of which gives insight into reactive pathways & precursors. Read more
14C-age tracers in global ocean circulation models Geoscientific Model Development DOI 10.5194/gmd-8-2079-2015 16 July 2015 The natural abundance of 14C in CO2 dissolved in seawater is often used to evaluate circulation and age in the ocean and in ocean models. We study limitations of using natural 14C to determine the time elapsed since water had contact with the atmosphere. We find that, globally, bulk 14C age is dominated by two equally important components, (1) the time component of circulation and (2) the “preformed 14C-age”. Considering preformed 14C-age is critical for an assessment of circulation in models. Read more
Decomposing uncertainties in the future terrestrial carbon budget associated with emission scenarios, climate projections, and ecosystem simulations using the ISI-MIP results Earth System Dynamics DOI 10.5194/esd-6-435-2015 13 July 2015 Our MS focused on uncertainties terrestrial C cycling under newly developed scenarios with CMIP 5 experiment. This study is first results to figure out the relative uncertainties of projected terrestrial C cycling in multiple projection components. Only using our new model inter-comparison project datasets enables us to evaluate various uncertainty sources in projection periods. The information about relative uncertainties are useful for climate science and the climate change impact evaluation. Read more
A contribution to the selection of tsunami human vulnerability indicators: conclusions from tsunami impacts in Sri Lanka and Thailand (2004), Samoa (2009), Chile (2010) and Japan (2011) Natural Hazards and Earth System Sciences DOI 10.5194/nhess-15-1493-2015 3 July 2015 Human vulnerability indicators used by the scientific community are validated in light of past tsunamis (2011 Japan, 2010 Chile, 2009 Samoa, 2004 Indian Ocean). Temporal exposure depends on livelihoods, traditions and gender roles. Vulnerable age groups are the elderly (highest mortality rates) and children. Female mortality is not always higher. There is a high correlation between damaged buildings and victims; distance to the sea, building materials and water depths determine type of damage. Read more
Development of a Global Fire Weather Database Natural Hazards and Earth System Sciences DOI 10.5194/nhess-15-1407-2015 30 June 2015 The authors of this study have developed a global database of daily, gridded Fire Weather Index System calculations beginning in 1980. Input data and two different estimates of precipitation from rain gauges were obtained from the NASA Modern Era Retrospective-Analysis for Research and Applications. This data set can be used for analyzing historical relationships between fire weather and fire activity, and in identifying large-scale atmosphere–ocean controls on fire weather. Read more
