Activity and abundance of denitrifying bacteria in the subsurface biosphere of diffuse hydrothermal vents of the Juan de Fuca Ridge Biogeosciences DOI 10.5194/bg-9-4661-2012 22 November 2012 Based on our rate measurements, and on published data on hydrothermal fluid fluxes and residence times, we estimated that up to ~10 Tg N yr−1could globally be removed in the subsurface biosphere of hydrothermal vents systems, thus, representing a small fraction of the total marine N loss (~275 to > 400 Tg N yr−1). Read more
Potential of semi-structural and non-structural adaptation strategies to reduce future flood risk: case study for the Meuse Natural Hazards and Earth System Sciences DOI 10.5194/nhess-12-3455-2012 21 November 2012 Our research suggests that annual flood risk may increase by up to 185% by 2030 compared with 2000, as a result of combined land-use and climate changes. The independent contributions of climate change and land-use change to the simulated increase are 108% and 37%, respectively. Read more
Bioerosion by microbial euendoliths in benthic foraminifera from heavy metal-polluted coastal environments of Portovesme (south-western Sardinia, Italy) Biogeosciences DOI 10.5194/bg-9-4607-2012 20 November 2012 We found that carbonate dissolution induced by euendoliths is selective, depending on the Mg content and morpho-structural types of foraminiferal taxa. This study provides evidences for a connection between heavy metal dispersion, decrease in pH of the sea-water and bioerosional processes on foraminifera. Read more
Urbanization suitability maps: a dynamic spatial decision support system for sustainable land use Earth System Dynamics DOI 10.5194/esd-3-157-2012 20 November 2012 Recent developments in land consumption assessment identify the need to implement integrated evaluation approaches, with particular attention to the development of multidimensional tools for guiding and managing sustainable land use. Land use policy decisions are implemented mostly through spatial planning and its related zoning. We propose a novel methodological approach to identify a decision-making process for land use allocation. Read more
Sea-spray geoengineering in the HadGEM2-ES earth-system model: radiative impact and climate response Atmospheric Chemistry and Physics DOI 10.5194/acp-12-10887-2012 16 November 2012 The radiative impact and climate effects of geoengineering using sea-spray aerosols have been investigated in the HadGEM2-ES Earth system model using a fully prognostic treatment of the sea-spray aerosols and also including their direct radiative effect. Read more
Development of a new data-processing method for SKYNET sky radiometer observations Atmospheric Measurement Techniques DOI 10.5194/amt-5-2723-2012 15 November 2012 In this study, we propose a new data processing method to improve single scattering albedo retrievals for the SKYNET sky radiometer network, which is one of the growing number of networks of sun-sky photometers, such as NASA AERONET and others. Read more
Technology and human purpose: the problem of solids transport on the Earth’s surface Earth System Dynamics DOI 10.5194/esd-3-149-2012 14 November 2012 Invoking purpose as a mechanism in solids advection is an example of the need to import anthropic principles and concepts into the language and methodology of modern Earth system dynamics. Read more
Future air quality in Europe: a multi-model assessment of projected exposure to ozone Atmospheric Chemistry and Physics DOI 10.5194/acp-12-10613-2012 13 November 2012 In order to explore future air quality in Europe at the 2030 horizon, two emission scenarios developed in the framework of the Global Energy Assessment including varying assumptions on climate and energy access policies are investigated with an ensemble of six regional and global atmospheric chemistry transport models. Read more
First middle-atmospheric zonal wind profile measurements with a new ground-based microwave Doppler-spectro-radiometer Atmospheric Measurement Techniques DOI 10.5194/amt-5-2647-2012 7 November 2012 We report on the wind radiometer WIRA, a new ground-based microwave Doppler-spectro-radiometer specifically designed for the measurement of middle-atmospheric horizontal wind by observing ozone emission spectra at 142.17504 GHz. Read more
Multi-generation gas-phase oxidation, equilibrium partitioning, and the formation and evolution of secondary organic aerosol Atmospheric Chemistry and Physics DOI 10.5194/acp-12-9505-2012 22 October 2012 A new model of secondary organic aerosol (SOA) formation is developed that explicitly takes into account multi-generational oxidation as well as fragmentation of gas-phase compounds, and assumes equilibrium gas-particle partitioning. Read more
Transition in the fractal geometry of Arctic melt ponds The Cryosphere DOI 10.5194/tc-6-1157-2012 19 October 2012 By analyzing data from hundreds of thousands of melt ponds, we find an unexpected separation of scales, where pond fractal dimension D transitions from 1 to 2 around a critical length scale of 100 m2 in area. The results impact sea ice albedo, the transmitted radiation fields under melting sea ice, the heat balance of sea ice and the upper ocean, and biological productivity such as under ice phytoplankton blooms. Read more
Combined wind measurements by two different lidar instruments in the Arctic middle atmosphere Atmospheric Measurement Techniques DOI 10.5194/amt-5-2433-2012 19 October 2012 The comparison of winds derived by RMR and sodium lidar is excellent for long integration times of 10 h as well as shorter ones of 1 h. Combination of data from both lidars allows identifying wavy structures between 30 and 110 km altitude, whose amplitudes increase with height. Read more
Assessment of remotely sensed drought features in vulnerable agriculture Natural Hazards and Earth System Sciences DOI 10.5194/nhess-12-3139-2012 19 October 2012 In this paper, the remotely sensed Reconnaissance Drought Index (RDI) is employed for the quantification of drought. RDI enables the assessment of hydro-meteorological drought, since it uses hydrometeorological parameters, such as precipitation and potential evapotranspiration. Read more
Rainfall intensity–duration thresholds for bedload transport initiation in small Alpine watersheds Natural Hazards and Earth System Sciences DOI 10.5194/nhess-12-3091-2012 18 October 2012 In this study, the characteristics of rainfall events leading to bedload transport were investigated in five small Alpine catchments located in different geographical and morphological regions of Switzerland, Italy and France. Read more
High-resolution interpolar difference of atmospheric methane around the Last Glacial Maximum Biogeosciences DOI 10.5194/bg-9-3961-2012 16 October 2012 Here we present new high-resolution methane records from the North Greenland Ice Core Project and the European Project for Ice Coring in Antarctica Dronning Maud Land ice cores covering Termination 1, the Last Glacial Maximum, and parts of the last glacial back to 32 000 years before present. Read more
Contrasting trends of mass and optical properties of aerosols over the Northern Hemisphere from 1992 to 2011 Atmospheric Chemistry and Physics DOI 10.5194/acp-12-9387-2012 15 October 2012 This study compares the long-term variation of mass and optical properties of atmospheric aerosols over the Northern Hemisphere, including China, the US, Canada and Europe. Contrasting trends of mass and optical properties were found from 1992 to 2011. Read more
Particle backscatter and relative humidity measured across cirrus clouds and comparison with microphysical cirrus modelling Atmospheric Chemistry and Physics DOI 10.5194/acp-12-9135-2012 5 October 2012 Advanced measurement and modelling techniques are employed to estimate the partitioning of atmospheric water between the gas phase and the condensed phase in and around cirrus clouds, and thus to identify in-cloud and out-of-cloud supersaturations with respect to ice. Read more
Marine bacteria in deep Arctic and Antarctic ice cores: a proxy for evolution in oceans over 300 million generations Biogeosciences DOI 10.5194/bg-9-3799-2012 5 October 2012 Ice cores offer the opportunity to study evolution of marine microbes over ~ 300 million generations by analysing their genomes vs. depth in glacial ice over the last 700 000 yr as frozen proxies for changes in their genomes in oceans. Read more
It takes a community to raise a hydrologist: the Modular Curriculum for Hydrologic Advancement (MOCHA) Hydrology and Earth System Sciences DOI 10.5194/hess-16-3405-2012 21 September 2012 In this paper we combine literature review, community survey, discussion and assessment to provide a holistic baseline for the future of hydrology education. The ultimate objective of our educational initiative is to enable educators to train a new generation of “renaissance hydrologists,” who can master the holistic nature of our field and of the problems we encounter. Read more
Should we apply bias correction to global and regional climate model data? Hydrology and Earth System Sciences DOI 10.5194/hess-16-3391-2012 21 September 2012 With this article, we advocate communicating the entire uncertainty range associated with climate change predictions openly and hope to stimulate a lively discussion on bias correction among the atmospheric and hydrological community and end users of climate change impact studies. Read more
Diurnal variations of organic molecular tracers and stable carbon isotopic composition in atmospheric aerosols over Mt. Tai in the North China Plain: an influence of biomass burning Atmospheric Chemistry and Physics DOI 10.5194/acp-12-8359-2012 18 September 2012 This study demonstrates that crop-residue burning activities can significantly enhance the organic aerosol loading and alter the organic composition and stable carbon isotopic composition of aerosol particles in the troposphere over the North China Plain. Read more
Incorporating student-centered approaches into catchment hydrology teaching: a review and synthesis Hydrology and Earth System Sciences DOI 10.5194/hess-16-3263-2012 13 September 2012 As hydrologists confront the future of water resources on a globalized, resource-scarce and human-impacted planet, the educational preparation of future generations of water scientists becomes increasingly important. Read more
Occurrence of lower cloud albedo in ship tracks Atmospheric Chemistry and Physics DOI 10.5194/acp-12-8223-2012 12 September 2012 The concept of geoengineering by marine cloud brightening is based on seeding marine stratocumulus clouds with sub-micrometer sea-salt particles to enhance the cloud droplet number concentration and cloud albedo, thereby producing a climate cooling effect. The efficacy of this as a strategy for global cooling rests on the extent to which aerosol-perturbed marine clouds will respond with increased albedo. It is found that the sign (increase or decrease) and magnitude of the albedo response in ship tracks depends on the mesoscale cloud structure, the free tropospheric humidity, and cloud top height. Read more
Improving the active involvement of stakeholders and the public in flood risk management – tools of an involvement strategy and case study results from Austria, Germany and Italy Natural Hazards and Earth System Sciences DOI 10.5194/nhess-12-2785-2012 11 September 2012 This paper presents basic elements and the application of two innovative approaches as a part of an “involvement strategy” that aims at the active involvement of all interested parties (stakeholders) for assessing, reviewing and updating flood risk management plans, as formulated in the EU Flood Risk Management Directive 2007/60/EC. Read more
The carbon budget of terrestrial ecosystems in East Asia over the last two decades Biogeosciences DOI 10.5194/bg-9-3571-2012 7 September 2012 We estimate the current terrestrial carbon balance of East Asia and its driving mechanisms during 1990–2009 using three different approaches: inventories combined with satellite greenness measurements, terrestrial ecosystem carbon cycle models and atmospheric inversion models. Read more
The “step feature” of suprathermal ion distributions: a discriminator between acceleration processes? Annales Geophysicae DOI 10.5194/angeo-30-1315-2012 5 September 2012 With this study, we draw the attention to the so-called “step feature” of the velocity distributions of suprathermal particles in the solar wind and offer a criterion that allows one to distinguish between those scenarios that employ velocity diffusion, i.e. second-order Fermi processes, which are prime candidates in the present debate. Read more
Water resources trends in Middle East and North Africa towards 2050 Hydrology and Earth System Sciences DOI 10.5194/hess-16-3101-2012 3 September 2012 Changes in water resources availability can be expected as consequences of climate change, population growth, economic development and environmental considerations. A two-stage modeling approach is used to explore the impact of these changes in the Middle East and North Africa region. Read more
Tree height integrated into pantropical forest biomass estimates Biogeosciences DOI 10.5194/bg-9-3381-2012 27 August 2012 Aboveground tropical tree biomass and carbon storage estimates commonly ignore tree height (H). We estimate the effect of incorporating H on tropics-wide forest biomass estimates in 327 plots across four continents using 42 656 H and diameter measurements and harvested trees from 20 sites to answer various questions. Read more
A synthesis of carbon in international trade Biogeosciences DOI 10.5194/bg-9-3247-2012 23 August 2012 In a globalised world, the transfer of carbon between regions, either physically or embodied in production, represents a substantial fraction of global carbon emissions. The resulting emission transfers are important for balancing regional carbon budgets and for understanding the drivers of emissions. Read more
The scientific basis for a satellite mission to retrieve CCN concentrations and their impacts on convective clouds Atmospheric Measurement Techniques DOI 10.5194/amt-5-2039-2012 23 August 2012 The cloud-mediated aerosol radiative forcing is widely recognized as the main source of uncertainty in our knowledge of the anthropogenic forcing on climate. Here, we present a new conceptual framework to help us overcome the challenges for improving our understanding, using relatively simple passive satellite measurements in the visible and infared (IR). Read more
Summer ammonia measurements in a densely populated Mediterranean city Atmospheric Chemistry and Physics DOI 10.5194/acp-12-7557-2012 20 August 2012 Real-time measurements of ambient concentrations of gas-phase ammonia (NH3) were performed in Barcelona (NE Spain) in summer between May and September 2011. Two measurement sites were selected: one in an urban background traffic-influenced area (UB) and the other in the historical city centre (CC). Read more
Value of medium range weather forecasts in the improvement of seasonal hydrologic prediction skill Hydrology and Earth System Sciences DOI 10.5194/hess-16-2825-2012 17 August 2012 We investigated the contribution of medium range weather forecasts with lead times of up to 14 days to seasonal hydrologic prediction skill over the conterminous United States (CONUS). Read more
Photoproduction of ammonium in the southeastern Beaufort Sea and its biogeochemical implications Biogeosciences DOI 10.5194/bg-9-3047-2012 10 August 2012 During the August 2009 Mackenzie Light and Carbon (MALINA) Program, the absorbed photon-based efficiency spectra of NH4+photoproduction (i.e. photoammonification) were determined using water samples from the SE Beaufort Sea, including the Mackenzie River estuary, shelf, and Canada Basin. Read more
Assessing climate model software quality: a defect density analysis of three models Geoscientific Model Development DOI 10.5194/gmd-5-1009-2012 9 August 2012 We found that the climate models all have very low defect densities compared to well-known, similarly sized open-source projects. We discuss the implications of our findings for the assessment of climate model software trustworthiness. Read more
Effects of business-as-usual anthropogenic emissions on air quality Atmospheric Chemistry and Physics DOI 10.5194/acp-12-6915-2012 1 August 2012 The atmospheric chemistry general circulation model EMAC has been used to estimate the impact of anthropogenic emission changes on global and regional air quality in recent and future years (2005, 2010, 2025 and 2050). The emission scenario assumes that population and economic growth largely determine energy and food consumption and consequent pollution sources with the current technologies (“business as usual”). Read more
Aerosol information content analysis of multi-angle high spectral resolution measurements and its benefit for high accuracy greenhouse gas retrievals Atmospheric Measurement Techniques DOI 10.5194/amt-5-1809-2012 27 July 2012 In this paper, we investigate the combined aerosol and greenhouse gas retrieval using multiple satellite viewing angles simultaneously. We find that this method greatly enhances the ability to retrieve aerosol properties by 2–3 degrees of freedom. Read more
Statistical adaptation of ALADIN RCM outputs over the French Alps – application to future climate and snow cover The Cryosphere DOI 10.5194/tc-6-785-2012 24 July 2012 In this study, snowpack scenarios are modelled across the French Alps using dynamically downscaled variables from the ALADIN Regional Climate Model (RCM) for the control period (1961–1990) and three emission scenarios (SRES B1, A1B and A2) for the mid- and late 21st century (2021–2050 and 2071–2100). Read more
Climatic and geologic controls on suspended sediment flux in the Sutlej River Valley, western Himalaya Hydrology and Earth System Sciences DOI 10.5194/hess-16-2193-2012 20 July 2012 Here, we present a comprehensive analysis of the spatiotemporal trends in suspended sediment flux based on daily data during the past decade (2001–2009) from four sites along the Sutlej River and from four of its main tributaries. Read more
Enhancing flood resilience through improved risk communications Natural Hazards and Earth System Sciences DOI 10.5194/nhess-12-2271-2012 20 July 2012 A framework of guiding recommendations for effective pre-flood and flood warning communications derived from the URFlood project (2nd ERA-Net CRUE Research Funding Initiative) from extensive quantitative and qualitative research in Finland, Ireland, Italy and Scotland is presented. Read more
Risk perception – issues for flood management in Europe Natural Hazards and Earth System Sciences DOI 10.5194/nhess-12-2299-2012 20 July 2012 Public perception of flood risk and flood risk information is often overlooked when developing flood risk management plans. As scientists and the public at large perceive risk in very different ways, flood risk management strategies are known to have failed in the past due to this disconnect between authorities and the public. This paper uses a novel approach in exploring the role of public perception in developing flood risk communication strategies in Europe. Read more
Detecting anthropogenic carbon dioxide uptake and ocean acidification in the North Atlantic Ocean Biogeosciences DOI 10.5194/bg-9-2509-2012 11 July 2012 Fossil fuel use, cement manufacture and land-use changes are the primary sources of anthropogenic carbon dioxide (CO2) to the atmosphere, with the ocean absorbing approximately 30% (Sabine et al., 2004). Ocean uptake and chemical equilibration of anthropogenic CO2 with seawater results in a gradual reduction in seawater pH and saturation states (Ω) for calcium carbonate (CaCO3) minerals in a process termed ocean acidification. Read more
Comparison of OH concentration measurements by DOAS and LIF during SAPHIR chamber experiments at high OH reactivity and low NO concentration Atmospheric Measurement Techniques DOI 10.5194/amt-5-1611-2012 11 July 2012 During recent field campaigns, hydroxyl radical (OH) concentrations that were measured by laser-induced fluorescence (LIF) were up to a factor of ten larger than predicted by current chemical models for conditions of high OH reactivity and low NO concentration. These discrepancies, which were observed in forests and urban-influenced rural environments, are so far not entirely understood. Read more
Searching for the seafloor signature of the 21 May 2003 Boumerdès earthquake offshore central Algeria Natural Hazards and Earth System Sciences DOI 10.5194/nhess-12-2159-2012 10 July 2012 Shaking by moderate to large earthquakes in the Mediterranean Sea has proved in the past to potentially trigger catastrophic sediment collapse and flow. On 21 May 2003, a magnitude 6.8 earthquake located near Boumerdès (central Algerian coast) triggered large turbidity currents responsible for 29 submarine cable breaks at the foot of the continental slope over ~150 km from west to east. Read more
Extrapolating glacier mass balance to the mountain-range scale: the European Alps 1900–2100 The Cryosphere DOI 10.5194/tc-6-713-2012 6 July 2012 This study addresses the extrapolation of in-situ glacier mass balance measurements to the mountain-range scale and aims at deriving time series of area-averaged mass balance and ice volume change for all glaciers in the European Alps for the period 1900–2100. Read more
Bioerosion by euendoliths decreases in phosphate-enriched skeletons of living corals Biogeosciences DOI 10.5194/bg-9-2377-2012 2 July 2012 While the role of microboring organisms, or euendoliths, is relatively well known in dead coral skeletons, their function in live corals remains poorly understood. They are suggested to behave like ectosymbionts or parasites, impacting their host’s health. However, the species composition of microboring communities, their abundance and dynamics in live corals under various environmental conditions have never been explored. Read more
Building an 18 000-year-long paleo-earthquake record from detailed deep-sea turbidite characterisation in Poverty Bay, New Zealand Natural Hazards and Earth System Sciences DOI 10.5194/nhess-12-2077-2012 27 June 2012 Our results show that the progressive characterisation of a turbidite record from a single sedimentary system can provide a continuous paleo-earthquake history in regions of short historical record and incomplete onland paleo-earthquake evidences. The systematic description of each turbidite enables us to infer the triggering mechanism. Read more
Novel water source for endolithic life in the hyperarid core of the Atacama Desert Biogeosciences DOI 10.5194/bg-9-2275-2012 26 June 2012 Our results explain how life has colonized and adapted to one of the most extreme environments on our planet, expanding the water activity envelope for life on Earth, and broadening the spectrum of possible habitats for life beyond our planet. Read more
Severe wind gust thresholds for Meteoalarm derived from uniform return periods in ECA&D Natural Hazards and Earth System Sciences DOI 10.5194/nhess-12-1969-2012 25 June 2012 In this study we present an alternative wind gust warning guideline for Meteoalarm, the severe weather warning website for Europe. There are unrealistically large differences in levels and issuing frequencies of all warning levels currently in use between neighbouring Meteoalarm countries. This study provides a guide for the Meteoalarm community to review their wind gust warning thresholds. Read more
Introduction to the European Monitoring and Evaluation Programme (EMEP) and observed atmospheric composition change during 1972–2009 Atmospheric Chemistry and Physics DOI 10.5194/acp-12-5447-2012 22 June 2012 European scale harmonized monitoring of atmospheric composition was initiated in the early 1970s, and the activity has generated a comprehensive dataset which allows the evaluation of regional and spatial trends of air pollution during a period of nearly 40 yr. Read more
Impact of heat and drought stress on arable crop production in Belgium Natural Hazards and Earth System Sciences DOI 10.5194/nhess-12-1911-2012 18 June 2012 Modelling approaches are needed to accelerate understanding of adverse weather impacts on crop performances and yields. The aim was to elicit biometeorological conditions that affect Belgian arable crop yield, commensurate with the scale of climatic impacts. Read more