Automated mineralogy based on micro-energy-dispersive X-ray fluorescence microscopy (µ-EDXRF) applied to plutonic rock thin sections in comparison to a mineral liberation analyzer Geoscientific Instrumentation, Methods and Data Systems DOI 10.5194/gi-6-429-2017 18 October 2017 This work describes a new approach to use fast X-ray fluorescence mapping as a tool for automated mineralogy applied on thin sections of plutonic rocks. Using a supervised classification of the spectral information, mineral maps are obtained for modal mineralogy and image analysis. The results are compared to a conventional method for automated mineralogy, which is scanning electron microscopy with mineral liberation analyzer, showing a good overall accuracy of 76 %. Read more
Seismic monitoring of small alpine rockfalls – validity, precision and limitations Earth Surface Dynamics DOI 10.5194/esurf-5-653-2017 16 October 2017 We use a seismometer network to detect and locate rockfalls, a key process shaping steep mountain landscapes. When tested against laser scan surveys, all seismically detected events could be located with an average deviation of 81 m. Seismic monitoring provides insight to the dynamics of individual rockfalls, which can be as small as 0.0053 m3. Thus, seismic methods provide unprecedented temporal, spatial and kinematic details about this important process. Read more
A growing threat to the ozone layer from short-lived anthropogenic chlorocarbons Atmospheric Chemistry and Physics DOI 10.5194/acp-17-11929-2017 12 October 2017 We have observed large amounts of man-made chlorine compounds in E and SE Asia and in the upper tropical troposphere. These relatively short-lived compounds are not controlled by the Montreal Protocol, but if significant quantities were able to reach the stratosphere, the long-term recovery of stratospheric ozone would be delayed. We have also identified an important atmospheric transport mechanism that can rapidly transport these chemicals from E Asia to the upper troposphere via the tropics. Read more
Balanced source terms for wave generation within the Hasselmann equation Nonlinear Processes in Geophysics DOI 10.5194/npg-24-581-2017 9 October 2017 The Hasselmann equation (HE) is the basis of modern surface ocean wave prediction models. Currently, they operate in theblack box with the tuning knobsmodes, since there is no consensus on universal wind input and wave-breaking dissipation source terms, and require re-tuning for different boundary and external conditions. We offer a physically justified framework able to reproduce theoretical properties of the HE and experimental field data without re-tuning of the model. Read more
Improving calibration and validation of cosmic-ray neutron sensors in the light of spatial sensitivity Hydrology and Earth System Sciences DOI 10.5194/hess-21-5009-2017 6 October 2017 A field-scale average of near-surface water content can be sensed by cosmic-ray neutron detectors. To interpret, calibrate, and validate the integral signal, it is important to account for its sensitivity to heterogeneous patterns like dry or wet spots. We show how point samples contribute to the neutron signal based on their depth and distance from the detector. This approach robustly improves the sensor performance and data consistency, and even reveals otherwise hidden hydrological features. Read more
Boundary layer models for calving marine outlet glaciers The Cryosphere DOI 10.5194/tc-11-2283-2017 5 October 2017 We show mathematically and computationally how discharge of ice from ocean-terminating glaciers is controlled by a combination of different forces acting on ice near the grounding line of a glacier and how that combination of forces is affected by the process of iceberg formation, which limits the length of floating ice tongues extending in front of the glacier. We show that a deeper fjord may lead to a longer ice tongue providing greater drag on the glacier, slowing the rate of ice discharge. Read more
Complex relationship between seasonal streamflow forecast skill and value in reservoir operations Hydrology and Earth System Sciences DOI 10.5194/hess-21-4841-2017 28 September 2017 This study investigates the relationship between skill and value of ensemble seasonal streamflow forecasts. Using data from a modern forecasting system, we show that skilled forecasts are more likely to provide benefits for reservoirs operated to maintain a target water level rather than reservoirs operated to satisfy a target demand. We identify the primary causes for this behaviour and provide specific recommendations for assessing the value of forecasts for reservoirs with supply objectives. Read more
The Plio-Pleistocene climatic evolution as a consequence of orbital forcing on the carbon cycle Climate of the Past DOI 10.5194/cp-13-1259-2017 25 September 2017 Ice ages are paced by astronomical parameters. On longer timescales, the astronomy also acts on climate, as evidenced by the 400 kyr signature observed in carbon isotopic records. In this paper, I present a conceptual model that links the astronomy to the dynamics of organic carbon in coastal areas. The model reproduces the carbon isotopic records and a two-step decrease in atmospheric CO2that would explain the Pleistocene (~ 2.8 Myr BP) and mid-Pleistocene (~ 0.8 Myr BP) transition. Read more
An explanation for the different climate sensitivities of land and ocean surfaces based on the diurnal cycle Earth System Dynamics DOI 10.5194/esd-8-849-2017 25 September 2017 We provide an explanation why land temperatures respond more strongly to global warming than ocean temperatures, a robust finding in observations and models that has so far not been understood well. We explain it by the different ways by which ocean and land surfaces buffer the strong variation in solar radiation and demonstrate this with a simple, physically based model. Our explanation also illustrates why nighttime temperatures warm more strongly, another robust finding of global warming. Read more
Response to Filchner–Ronne Ice Shelf cavity warming in a coupled ocean–ice sheet model – Part 1: The ocean perspective Ocean Science DOI 10.5194/os-13-765-2017 21 September 2017 A coupled model has been developed to study the interaction between the ocean and the Antarctic ice sheet. Simulations for present-day climate yield realistic ice-shelf melt rates and a grounding line position close to the observed state. In a warm-water-inflow scenario, the model suggests a substantial thinning of the ice shelf and a local retreat of the grounding line. The coupled model yields a stronger increase in ice-shelf basal melt rates than a fixed-geometry control experiment. Read more
