bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical sensitivity analysis of a rock glacier flow model versus detection of an internal sliding occurrence
Authors: Mansutti Daniela , Kannan Krishna , Rajagopal Kumbakonam R.
Published: March 2020

This work concerns the rock glacier flow model introduced, in its basic form, by Kannan and Rajagopal in [1]  and extended with inclusion of temperature effects by Kannan, Rajagopal, Mansutti and Urbini in [2]. This one is based on the general conservation laws (momentum, mass and energy) and takes into account the effect of shear rate, pressure and rocks and sand grains volume fraction onto viscosity, also by implementing the effects of local pressure melting point variation. Here we present the results of a sensitivity analysis of the parameters developed by shooting the location of the internal sliding occurence, induced by the presence of rocks and sand grains trapped within the interstices of the glacier, and the value of the shear velocity.  The case of the Murtel-Corvatsch glacier in Switzerland is considered for the availability of the detailed description based on measured data published by Arenson, Hoelzle and Springman in [3].
The numerical results obtained improve those ones presented in [1] and show clearly the contribution of each numerical and functional parameter of the model. They also exhibit a very good agreement with observations which makes this modelling approach very promising for general application.
[1] Kannan, K., Rajagopal, K.R.: A model for the flow of rock glaciers. Int. J. Non-lin. Mech., 48, pp. 59– 64 (2013) 
[2] Kannan, K., Mansutti, D., Rajagopal, K.R. and Urbini, S.: Mathematical modeling of rock glacier flow with temperature effects, in Mathematical Approach to Climate Change and its Impacts (P. Cannarsa, D. Mansutti and A. Provenzale, eds.), pp. 137-148, Springer-INDAM series, vol.38 (2020) 
[3] Arenson, L., Hoeltzle, M. and Springman, S.: Borehole Deformation Measurements and Internal Structure of Some Rock Glaciers in Switzerland. Permafrost and Periglacial Processes, 13, pp. 117-135 (2002).

Acknowledgements: D. Mansutti acknowledges Piano Nazionale Ricerca Antartide (PNRA) for financial support of this topic within the project ENIGMA (project PNRA$16-00121$).
Moisture and humidity dependence of the above-ground cosmic-ray neutron intensity
Authors: Weimar Jannis , Köhli Markus , Schrön Martin , Schmidt Ulrich
Published: March 2020

The novel method of Cosmic-ray neutron sensing (CRNS) allows non-invasive soil moisture measurements at a hectometer scaled footprint. Using this technique one can relate the flux density of albedo neutrons, generated in cosmic-ray induced air showers, to the amount of water within a radius of several hundred meters. In the recent years the understanding of neutron transport by Monte Carlo simulations led to major advancements in precision, which have successfully targeted a manifold of use cases. For example the improvements in the signal interpretation have meanwhile also been applied to the determination of snow water in Alpine regions. Up to now, the conversion of soil moisture to a detectable neutron count rate relies mainly on the equation presented by Desilets and Zreda. While in general a hyperbolic expression can be derived from theoretical considerations, their empiric parameterisation needs to be revised as many groups have found site-specific calibrations, which are simply based on different empirical data sets.

Investigating the above-ground neutron intensity by a broadly based Monte Carlo simulation campaign revealed a more detailed understanding of different contributions to this signal, especially targeting air humidity corrections. The packages MCNP and URANOS were used to derive a function able to describe the respective dependencies including the effect of different hydrogen pools and the sensor response function. The resulting formula significantly improves the soil-moisture-to-intensity conversion and allows for a more comprehensive instrument data quality, which especially closes the gap between observations of very dry and wet conditions.
KET 02: An electron and ion telescope for an interstellar mission
Authors: Heber Bernd , Wimmer-Schweingruber Robert , Köberle Marlon , Kühl Patrick , Böttcher Stephan
Published: March 2020

The recent AMS 02 measurements show that the very local interstellar spectra (VLIS) for galactic cosmic rays cannot be directly measured at the Earth below rigidities of 40-60 GV because of solar modulation. With Voyager 1and Voyager II crossing the heliopause in 2012 and 2018, in situ experimental LIS data below 100 MeV/nuc constrain computed galactic CR spectra. However, the energy spectra in between can so far only be derived by models. This gap could be narrowed by flying an instrument like the The COsmic and Solar Particle INvestigation Kiel Electron Telescope (COSPIN/KET) that measured protons and alpha-particles in the energy range from about 4 to above 2000 MeV/n and electrons in the range up to 10 GeV in distinguished energy channels. Such a telescope would consist of two parts: 1) an entrance telescope of two semiconductors comprising a silica-aerogel Cherenkov detector with a refractive index of 1.066, selecting particles with speeds v/c = b > 0.938, and 2) a calorimeter, a lead-fluoride Cherenkov detector followed by a scintillation detector measuring escaping particles.
Investigating the interactions between Forest Cover Change and Hydroclimatic patterns in the Bolivian Amazon basin over the last 30 years
Authors: Wongchuig Correa Sly , Espinoza Jhan Carlo , Segura Hans , Condom Thomas , Junquas Clémentine
Published: March 2020

Large evidences support the strong impacts on rainfall amount and the increasing of dry-season length on the Amazonian forest. All of these effects are usually attributed to large scale atmospheric circulation and to land cover changes as part of anthropogenic effects. In this research we assess statistical and modeling approaches to investigate the interaction between changes in forest cover and hydroclimate processes on a regional and local scale.

Henceforth, the deforestation areas and climatic indexes for the southern Amazon basin (south of 14°S) were evaluated. The deforestation map was estimated for the 1992-2018 period, based on global land cover maps at 300 m of spatial resolution produced by the European Space Agency (ESA) Climate Change Initiative (CCI) by using several remote sensing datasets. The CHIRPS rainfall dataset (P) for the 1981-2018 period was used to estimate the dry day frequency (DDF, P<1mm) and the wet day frequency (WDF, P>10mm). In addition, the mean actual seasonal evapotranspiration (AET) was GLEAM and ET-Amazon evapotranspiration datasets for the 1980-2018 and 2003-2013 periods respectively. In order to determine the local and the regional climatic effect for each pixel of the climatic index (DDF, WDF and AET), the deforestation fraction was estimated considering different spatial radii of influence (20 to 50 km).

The first results indicate a particular pattern in the southern Bolivian Amazon where two groups of areas were identified, considering the common period of analysis (1992-2018). One of them shows a significant relationship between increasing trend of DDF and decreasing trend of WDF while deforestation fraction is high, what mainly occurs during the wet season. In addition, this region is clearly placed in areas with values of deforestation fraction above ~30%, a closest value to the usually estimated Amazon Tipping Point (~40%). Below this value, the second group is also located in regions with positive trends of DDF and negative trends of WDF. This region has probably a strongest link with the large-scale climate.

Considering these preliminary results, the statistical approaches developed in this research could give some insights about the interactions between forest change and the regional hydro climatology, which might improve the understanding of this interaction based on large-scale hydrological modeling.
Stress and deformation analysis in the Norwegian Barents Sea in relation to Paleogene transpression along the Greenland-Eurasia plate boundary
Authors: Gac Sebastien , Minakov Alexander , Shephard Grace E. , Faleide Jan Inge , Planke Sverre
Published: March 2020

Cenozoic small-scale contractional structures are widespread in the Norwegian (west) and Russian (east) Barents Sea. While the exact dating of the deformation is unclear, it can only be inferred that the contraction is younger than the early Cretaceous. One likely contractional mechanism is related to Greenland plate kinematics at Paleogene times. We use a thin plate finite element modelling approach to compute stresses and deformation within the Norwegian Barents Sea in response to the Greenland-Eurasia relative motions at Paleogene times. The analytical solution for the 3-D folding of sediments above basement faults is used to assess possibilities for folding. Two existing Greenland plate kinematic models, differing slightly in the timing, magnitude and direction of motion, are tested. Results show that the Greenland plate’s general northward motion promotes growing anticlines in the Norwegian Barents shelf. Folding is more likely in the northern Norwegian Barents Sea than in the south. Folding is correlated with the Greenland plate kinematics through time: model M2 predicts a main phase of contraction at earliest Eocene while model M1 predicts contraction a bit later in the Eocene. Both models successfully explain folding above NW-SW Timanian trended faults in the southern Norwegian Barents Sea and above SSW-NNE Caledonian-trended faults in the north. We conclude that Paleogene Greenland plate kinematics are a likely candidate to explain contractional structures in the Norwegian Barents Sea.
Parental magma composition of the Main Zone of the Bushveld Complex: Evidence from in-situ LA-ICP-MS trace element analysis of silicate minerals in the cumulate rocks
Authors: Yang Shenghong , Maier Wolfgang D. , Godel Belinda , Barnes Sarah-Jane , Hanski Eero , O'Brien Hugh
Published: March 2020

In-situ trace element analysis of cumulus minerals may provide a clue to the parental magma from which the minerals crystallized. However, this is hampered by effects of the trapped liquid shift (TLS). In the Main Zone (MZ) of the Bushveld Complex, the Ti content in plagioclase grains shows a clear increase from core to rim, whereas most other elements (e.g., rare earth elements (REEs), Zr, Hf, Pb) do not. This is different from the prominent intra-grain variation of all trace elements in silicate minerals in mafic dikes and smaller intrusion, which have a faster cooling rate. We suggest that crystal fractionation of trapped liquid occurred in the MZ of Bushveld and the TLS may have modified the original composition of the cumulus minerals for most trace elements except Ti during slow cooling. Quantitative model calculations suggest that the influence of the TLS depends on the bulk partition coefficient of the element. The effect on highly incompatible elements is clearly more prominent ­­than on moderately incompatible and compatible elements because of different concentration gradients between cores and rims of cumulate minerals. This is supported by the following observations in the MZ of Bushveld: 1) positive correlation between Cr, Ni and Mg# of clinopyroxene and orthopyroxene, 2) negative correlation between moderately incompatible elements (e.g., Mn and Sc in clinopyroxene and orthopyroxene, Sr, Ba, Eu in plagioclase), but 3) poor correlation between highly incompatible elements and Mg# of clinopyroxene and orthopyroxene or An# of plagioclase. Modeling suggests that the extent of the TLS for a trace element is also dependent on the initial fraction of the primary trapped liquid, with strong TLS occurring if the primary trapped liquid fraction is high. This is supported by the positive correlation between highly incompatible trace element abundances in cumulus minerals and whole-rock Zr contents.

We have calculated the composition of the parental magma of the MZ of the Bushveld Complex. The compatible and moderately incompatible element contents of the calculated parental liquid are generally similar to those of the B3 marginal rocks, but different from the B1 and B2 marginal rocks. For the highly incompatible elements, we suggest that the use of the sample with the lowest whole-rock Zr content and the least degree of TLS is the best approach to obtain the parental magma composition. Based on calculation, we propose that a B3 type liquid is the most likely parental magma to the MZ of the Bushveld Complex.
Empirical modelling of beach evolution: implementation of coupled cross-shore and longshore approaches
Authors: Chataigner Teddy , Yates Marissa , Le Dantec Nicolas
Published: March 2020

Understanding shoreline evolution, and in particular, the consequences of shoreline erosion is a
major societal concern that threatens to become even more important in the future with the impacts
of climate change. Thus, it is necessary to improve both knowledge of the dominant physical processes
controlling medium to long-term shoreline evolution and the capabilities of morphological evolution
models to simulate beach changes at these spatial and temporal scales.
Empirical models may be an ideal choice for modelling complex and dynamic environments such as
sandy beaches at large spatial (beach) and long temporal (years to decades) scales. They reproduce
the effects of the main morphodynamical processes with low computational cost and relatively high
accuracy, in particular when high quality, long-term data are available for calibration.
Here, to broaden its range of application, a cross-shore equilibrium model, which has demon-
strated its accuracy and efficiency in reproducing shoreline and intertidal beach profile changes at
several micro and macrotidal beaches, is extended to couple it with a longshore beach evolution
modelling approach. The selection of a particular longshore model (based on a one-line approach),
and its implementation and validation with benchmark test cases of shoreline evolution caused by
the effects of diffusion, high angle wave instabilities, and coastal structures are presented.
The new hybrid model is applied at Narrabeen beach to reproduce the long-term evolution of
beach contours near the shoreline. The model is calibrated and tested using the 40-year timeseries of
monthly subaerial beach profile surveys conducted along 5 cross-shore profiles along the 3.6km-long
Narrabeen-Collaroy embayment. The novelty of the current work is to focus on reproducing changes
at different altitudes, with the objective of assessing the cross-shore variability of the longshore
sediment flux, which is assumed constant in most one-line longshore transport models. The coupled
model performance is discussed, and the results are compared to existing studies that have simulated
shoreline evolution at Narrabeen using other morphological change models.
Evolution of the CAMS global air quality forecasting system
Authors: Kipling Zak , Ades Melanie , Agusti-Panareda Anna , Barré Jérôme , Bousserez Nicolas , Dominguez Juan-José , Engelen Richard , Flemming Johannes , Garrigues Sebastien , Huijnen Vincent , Inness Antje , Jones Luke , Parrington Mark , Razinger Miha , Peuch Vincent-Henri , Rémy Samuel , Ribas Roberto , Suttie Martin
Published: March 2020

As part of the Copernicus Atmosphere Monitoring Service (CAMS), operated by ECMWF on behalf of the European Commission, global analyses and forecasts of atmospheric composition have been produced operationally since 2015. These were built on many years of previous work under the GEMS and MACC projects, which began producing regular forecasts in 2007.

Since the transition to an operational service, there have continued to be many new developments and improvements to the system in five major upgrades, including increased horizontal and vertical resolution, updated emissions and paramterisations, additional species such as nitrate aerosol, as well as updates to the underlying meteorological model and data assimilation. The components of this system (aerosols, gas-phase chemistry, meteorology and the ocean) are also now coupled more tightly via active feedbacks then ever before.

In this interactive presentation, we will demonstrate the impact of a number of these developments on the performance of the resulting global air quality forecasts, alongside the continuing evolution of our approaches to assessing model improvement against independent in-situ and remote-sensing observations from a variety of platforms.

Because the continuing evolution of an operational system can make the analysis of long-term trends problematic, we will also contrast this with the CAMS global reanalysis product, which (while not using the very latest version of the model) do provide a consistent long-term dataset from 2003 onwards.
Optical and geometrical properties of Arctic clouds over northern Finland during PaCE campaign in 2019
Authors: Shang Xiaoxia , Komppula Mika , Giannakaki Elina , Bohlmann Stephanie , Filioglou Maria , Brus David
Published: March 2020

In the Arctic areas the influence of climate change is being felt at a higher degree than elsewhere. Enabling a better understanding of the environment in region is of high importance. Clouds play a significant role in the energy budget and the hydrological cycle of the Earth’s atmosphere system. In order to provide insights into Arctic cloud processes for Arctic cloud-climate studies, the field campaign PaCE (Pallas Cloud Experiment) was organized during autumn and winter 2019; the campaign was focusing on aerosol and cloud vertical profiling using in-situ and remote sensing techniques.

During the campaign, a ground-based multi-wavelength Raman polarization lidar PollyXT performed continuous measurements from September to December 2019, at the Kenttärova station (N 67°59’14”, E 24°14’35”, 347 m above sea level) at Pallas, in the northern Finland. This is a background station surrounded by the forest, where the atmosphere is quite clean. Cloud vertical structures and optical properties have been determined from lidar analysis. During day-time, the Klett method is applied to retrieve the vertical profiles of cloud extinction and backscatter coefficient at three wavelengths (355 nm, 532 nm and 1064 nm). During night-time, the standard Raman method is used to provide additional lidar ratio profiles at 355 nm and 532 nm. The actual linear depolarization ratio at two wavelengths (355 nm and 532 nm) are also retrieved. With water vapor channel at 407 nm, the relative humidity profile are also available for received signal with good signal-to-noise ratio. The combined use of near and far field telescopes provides reliable vertical profiles of optical properties from 0.25 km to 10 km above ground level. The temperature and thickness dependencies on optical properties have also been studied in detail. Geometrical properties of cloud are retrieved using both lidar and ceilometer, statistic values of cloud height, and thickness are shown.
Forecasting landslides using a spatiotemporal analysis of remote sensing data
Authors: Mesa Zuluaga Carlos Alfredo , Santos Granados German Ricardo , Corzo Perez Gerald Augusto
Published: March 2020

Forecasting landslides is highly dependent in the weather conditions and the land-soil characteristics and its state. The uncertainty present in the evaluation of precipitation and its continuous variation is always a challenge for having accurate forecast, of primary importance for risks reduction. Currently, the landslides generate an impact on the imbalance of ecosystems and their occurrence is increasing which leads to an increase in the vulnerability of man on earth. The complexity of the landslide systems requires detailed analysis of the highly dynamic information of the rain and in turn the form as the hydrology response. Being able to combine hydrological models forced by satellite information systems and put them with a soil cohesion analysis system could help improve monitoring and in a particular case forecast landslide events.

The Combeima river located at the village of Juntas with canyon type land relief currently, faces a vital challenge in the face of winter times where precipitation threaten urban zones. Current researchers have explored risk factors, however, results still are quite far from optimal.

This study develops a methodology to identify the water volume that can cause landslides over the canyon type land relief, and use it as a trigger for forecasting. Remote sensing data at the present time and projected from past data will be used to simulate forecasting situations (hidcasting). A coupled Mike SHE models and data from Google earth platform are used to analyze a period of twenty years. Local information from events and its analysis in the satellite images are used to validate the events. Finally, the results of past conditions that led to the generation of floods are used to identify the state of the soil and the volumes. A calibration and validation of a neural network model is done feeding the volumes and states. The results of the model allow us to specifically characterize the saturation limits of the soil and the maximum rainfall intensities that a soil may contain before collapsing. With this information a high performance and a design of a system to forecast in real time was proposed. This work is part of an ongoing research and partial results will be presented.
Regional Characterisation of Soils from Ground, Air and Space
Authors: Meyer Uwe , Frei Michaela , Fries Elke
Published: March 2020

The Federal Institute for Geosciences and Natural Resources has recently launched a project to characterise soils and soil patterns using smart sets of newly developed and existing technologies on regional scales. The focus lies on the combination of airborne geophysical tools like gamma ray spectrometry and remote sensing techniques such as VIS-NIR-SWIR-LWIR hyperspectral and thermal infrared imagery. In order to calibrate the measurements all given methods will be implemented on ground and on soil samples in the laboratory. Additionally, geochemical, mineralogical and physical investigations well established in soil sciences will be incorporated. The aim is to map and evaluate the physical properties acquired from drones, helicopter and satellites. Using statistical methods and means of artificial intelligence areas of homogeneous physical soil properties will be determined.  The resulting areas will be compared to soil classification maps and the distribution of soil substrates. Self organising map systems will be used for correlation of homogeneous areas and later interpretation. Major care will be taken to reduce effects from varying soil moisture and surface vegetation. The presentation will focus on ground based, airborne and space platforms and their instrumentation and current developments. Apart from off-road vehicles at least three different sets of drones will be used for detailed surveying, implementing newly developed gamma ray sensing systems, hyperspectral and thermal infrared cameras. The BGR helicopter will be equipped with a high-end gamma spectrometer and imaging hyperspectral sensors. We envisage using future hyperspectral EnMAP data to evaluate it against the helicopter results and further up- and downscaling strategies.
Non-eruptive Uplift and Subsidence episodes beneath the Hengill Triple Junction, SW Iceland
Authors: Ducrocq Cécile , Geirsson Halldór , Árnadóttir Thóra , Juncu Daniel , Kristjánsson Bjarni R. , Gunnarsson Gunnar , Drouin Vincent
Published: March 2020

Non-eruptive uplift and subsidence episodes at volcanic systems have been observed on volcanic systems around the world and understanding the complex source processes of the deformation is key to mitigate the hazard assessment or geothermal potential of the area. The Hengill area, an approximately 100 km² area in SW Iceland, located at the triple junction of the Eurasian plate, North-American plate and Hreppar Microplate, is one such example of a complex deforming volcanic system. The triple junction accommodates a total spreading and shear of 1.8 cm/yr through a systems of spreading ridges and “bookshelf-faulting” processes. The two active volcanoes of the area (Hrómundartindur and Hengill), last erupted ~2000 years ago. Beneath these adjacent volcanic systems, deep sources (5-7 km depth) caused successive episodes of broad-scale uplift (1993 – 1999; 2017 – 2018) and subsidence (2006 – 2017; 2018 – ongoing at the time of writing) in the area. These deep sources may be closely related as they have been located only 2-3 km from each other within the brittle-ductile transition zone of the area. More superficial sources (depth < 3 km) of deformation are also observed in the Hengill area, related to the extraction and injection of fluids in the Nesjavellir and Hellisheiði geothermal power plants.

Through the combination of GNSS, InSAR, analytical models and geophysical data sets from the area we investigate the spatial and temporal relation between these deep sources. The observed ground motions associated with these deep sources may be magmatic in nature (e.g. magma accumulation, degassing of older intrusions), however previous seismic tomography work (Tryggvason et al. 2002) in the area does not suggest a large partially melted magmatic body at those depths, hinting that other processes (e.g. hydrothermal) may be at the origin of some of these episodes. The correlation of geodetic measurements with geophysical and geothermal datasets may bring clues to constrain the nature of uplift and subsidence episodes in volcanic and high temperature geothermal areas such as the Hengill area.
Characterization of an improved PTR3 mass spectrometer for the detection of highly oxidized aerosol precursors
Authors: Leiminger Markus Sebastian , Reinecke Tobias , Müller Markus , Feil Stefan , Sulzer Philipp , Jordan Alfons
Published: March 2020

The recently introduced PTR3-TOF mass spectrometer (Proton Transfer Reaction Time-Of-Flight) allows for a direct and quantitative detection of volatile organic compounds (VOC) and their oxidation products. With a design of the inlet system and the ionization chamber that allows analyte transfer with virtually no wall interactions, organics ranging from volatile to extremely low volatility (ELVOC) can be measured, even at ambient temperature. In addition, PTR3 has recently shown to detect and quantify RO2 radicals. Unlike the traditional PTR-MS ionization technique, the PTR3 is operated at an elevated reaction pressure of 50 to 80 mbar while reaction kinetics are precisely defined via radial electric fields emitted from a tripole ion guide. With this setup, outstanding sensitivities of more than 30,000 cps/ppbV are achieved.

Herein, we present an improved version of a PTR3-TOF instrument. The inlet comprises three cylindrically arranged ion sources allowing for fast electrical switching between a set of reagent ions including H3O+, NO+, O2+ and NH4+. The tripole geometry is aerodynamically improved to further reduce surface interactions. Extraction of analyte ions from the PTR3 ionization chamber and subsequent transfer to the TOF mass analyzer is now enhanced by an ion booster in series to a hexapole ion guide. This setup enables a precise control of extraction energies to reduce unwanted collision induced fragmentation and at the same time efficiently transmits ions of a broad m/z range. Analyte ions are analyzed with a high-resolution Time-Of-Flight mass spectrometer achieving mass resolving powers of typically 13,000 to 15,000.

We have characterized the performance of this optimized PTR3-TOF instrument using pure chemical compounds of intermediate to low volatility, including carboxylic acids and peroxides. Hereby, the effects of PTR3 reaction conditions and ion extraction settings are studied. Monoterpene ozonolysis experiments demonstrate the performance in detecting aerosol precursors from intermediate to extremely low volatility. These new insights in gas phase chemistry are further combined with particle phase measurements conducted with a CHARON PTR-MS to emphasize the analytical capabilities of the PTR3.
Source mechanism solutions of low frequency Martian events based on body wave coda from a single seismic station
Authors: Brinkman Nienke , Jacob Alice , Stähler Simon , Schmelzbach Cédric , Fuji Nobuaki , Perrin Clément , Batov Alex , Böse Maren , Clinton John , van Driel Martin , Drilleau Mélanie , Giardini Domenico , Gudkova Tamara , Robertsson Johan Olof Anders , Banerdt William Bruce ,   MQS frontline and review team
Published: March 2020

On the 26th of November 2018, NASA’s InSight lander successfully touched down on the Martian ground in Elysium Planitia. The lander transported among other instruments a single three-component broadband seismometer to measure seismic events and subsequently determine the seismic activity level and eventually the internal structure of Mars. In this study we focus on characterizing the source mechanisms of the highest-quality marsquakes detected so far: The events with highest SNR occurred on sols 173 (S0173a, May 23rd 2019) and 235 (S0235b, July 27th 2019) with Mw > 3.5, showing clearly polarized P and S waves. The InSight MarsQuake Service has estimated their distances to be around 27 degrees, nearby the Cerberus Fossae Graben system. Two more events, S0183a and S0325b have less clear body wave phases and locations, but are also interpreted to be related to it.

We have developed a grid-search based method to fit synthetic waveforms to the observed first arriving P and S wave trains. The four source parameters we invert for in this study are the three unique orientation angles of the source mechanism, strike (φ), dip (δ) and rake (λ), and the depth of the event. Synthetic seismograms are generated by computing Green’s functions based on the epicentral distance determined by the InSight MarsQuake Service (MQS) and radially symmetric velocity models. These Green’s function are then convolved with a source time function including an estimated global body wave attenuation to obtain realistic seismograms. 

The two high-quality event recordings originating from the Cerberus Fossae (CF) fault system were analyzed. Multiple velocity models, frequency bands and window lengths around the arriving phases were used to explore the non-uniqueness in the inverse problem of the inherently ambiguous single-station data. We found that using plausible structural models based on geophysical modeling, the first 10-15 seconds of the waveforms can be fit, constraining the source mechanism and depth, but that the estimation of the uncertainty remains challenging.
Can performance metrics accounting for the flood extent shape improve inundation model calibration?
Authors: Assumpção Thaine H. , Popescu Ioana , Jonoski Andreja , Solomatine Dimitri P.
Published: March 2020

The calibration and validation of inundation models have since long been influenced by data availability. When only stage hydrographs and high water level marks were available, metrics such as the Root Mean Square Error (RMSE) were selected for goodness-of-fit assessment. When remotely sensed flood extent data started to be obtained, binary performance measures started being used. Although data availability and modelling resolution have advanced in the past decades, the methods behind performance evaluation remain similar. Shape-based metrics used in topology and pattern recognition could enhance not only the raw model performance but our ability to diagnose achieved results. Therefore, in this study, we discuss how much improvement in calibration can be obtained by employing shape matching metrics. The research is conducted in two experiments: a 2D hydrodynamic benchmarking model and the Po River case study. Different metrics traditionally used in inundation modelling and metrics tailored towards shape matching were employed. Calibration of the Manning coefficient was performed using one metric at a time. Experiments showed that metrics incorporating scale components (e.g. differences in areas and/or distances) provide better calibration. This corroborates the wide use of traditional metrics and indicates the potential of using shape-based metrics, which can augment our ability to diagnose models and improve modelling results.
Response of heterotrophic respiration and oxidation of atmospheric CH4 to changes in soil moisture and temperature in drylands across a global climate and ecosystem gradient
Authors: Hessilt Thomas , Lyberth Hauptmann Daniel , Riis Christiansen Jesper
Published: March 2020

Soil moisture and temperature collectively regulate the production and consumption of carbon in soils. With expected changes in both the soil thermal and hydrological regimes globally, experimental data on carbon turnover under these changes in contrasting ecosystems are important for constraining predictive models of soil carbon turnover. We investigated the effect of changes in soil water and temperature on heterotrophic respiration (Rh) and net methane uptake (MU) in soils from grassland ecosystems in Arctic, temperate and subtropical climates.
The temperature sensitivity of RH increased with decreasing mean annual temperature, but there was no indication of a site-specific response of Rh to changes in soil moisture. All sites displayed MU, primarily controlled by the soil water content with little temperature dependence. Thus, the optimum temperature for MU did not differ between sites despite the differences in the climate. However, the optimal soil water content for the relative maximum MU decreased with increasing mean annual temperature at the sites.
These results point to site-specific adaptation of the microbial community that governs the sensitivity of Rh to temperature, but not soil moisture and the dependency of MU to soil moisture alone. We would also like to discuss how this insight can be used to inform ecosystem models.
Simulating heavy rainfall events for parameterizing a first application of the physically based soil erosion model EROSION3D in South Africa
Authors: Kaiser Andreas , Geißler Michael , Le Roux Jay , Stander Marike , van Zijl George , Baade Jussi
Published: March 2020

Soil erosion is a frequently tackled field of research and plays a major role in land degradation. Representing a discontinuous process soil loss is strongly determined by single events, which leads to high demands on modelling approaches.

Here we present a first application of the physically-based soil erosion model EROSION3D in a South African setting within the framework of the project SALDi (South African Land Degradation Monitor). Parameterization of the model requires intensive field work in accordance to land use and management patterns, soil types and topography. The experimental determination of physical and hydrological processes for selected sites allows for an improvement of the modelling results. Thus, rainfall and runoff simulation campaigns were carried out on various sites with a 3 x 1 m² mobile rainfall simulator. Additionally, UAV and TLS surveying, soil sampling, laboratory analysis and digital soil mapping complemented the approach. The created datasets are firstly handled in EROSION2D to calibrate soil erosivity and hydraulic conductivity and then introduced to EROSION3D for including land use, precipitation, elevation, multi-layered soil properties, organic carbon content and additional model input parameters.

The modelling procedure was applied within the boundaries of a research catchment close to Ladybrand in the Free State for first test runs. Furthermore, the same approach showed distinct differences on a conventionally tilled field vs. a conservational approach. An upscaling to larger catchments will then be carried out in basins with protected soils within Kruger National Park to directly compare them to results from intensively cultivated agricultural sites adjacent to the park boundaries.
Re-assessment of pre-industrial fires in CMIP6 models and the implications for radiative forcing
Authors: Carslaw Ken , Scott Cat , Yoshioka Masaru , Hamilton Douglas , O’Connor Fiona , Folberth Gerd , Mulcahy Jane , Dalvi Mohit , Balkanski Yves , Checa-Garcia Ramiro , Olivie Dirk , Schulz Michael , Michou Martine , Nabat Pierre , Nieradzik Lars , van Noije Twan , Bergman Tommi
Published: March 2020

Assessment of anthropogenic radiative forcing requires a robust understanding of the composition of the pre-industrial baseline atmosphere from which calculations are made

It is often assumed that fire activity and the associated aerosol emissions were lower in the pre-industrial period than in the present day. However, some lines of evidence suggest that fire activity may have halved since the pre-industrial period. 

Here we compare the simulated ratio of pre-industrial (c.1750CE and c.1850CE) to present-day black carbon surface concentrations in five ESMs (CNRM-ESM2-1, EC-Earth3, IPSL-CM6, NorESM1.2, UKESM1), using historical fire emissions from the Sixth Coupled Model Intercomparison Project (CMIP6), to the ratio in Northern Hemisphere ice-core records. 

We find that when forced with CMIP6 fire emissions all ESMs overestimate the present-day to pre-industrial black carbon ratio. This is consistent with previous studies and suggests that the contribution of fire to the composition of the pre-industrial atmosphere may be too low. If the contrast between the pre-industrial and present-day atmospheres in these models is too great, they are likely to overestimate the strength of the anthropogenic aerosol radiative forcing.  

We extend our analysis to include additional ESMs providing historical simulations for CMIP6, as included in the IPCC’s Sixth Assessment Report.

 
Seismo-acoustic analysis of Debris Flows events at the Illgraben catchment, Switzerland
Authors: Belli Giacomo , Marchetti Emanuele , Walter Fabian , McArdell Brian
Published: March 2020

Debris flows are episodic strongly impacting gravitational currents of generally high density, consisting of mixtures of water and debris in varying proportions and occurring in steep mountain torrents with volumes commonly exceeding thousands of m3. Despite the observation that debris flows are among the most dangerous processes in mountain environments, the moderate flow velocities (typically < 10 m/s) make early warning in principle possible if the flows are detected early upon formation.

Seismic and infrasound studies of debris flows rapidly increased in the last decade but focused mostly on event detectability and application as early-warning systems. Seismic networks, arrays of infrasound sensors and the combined use of a collocated single seismic and infrasound sensors, have turned out to be efficient systems for detecting the occurrence of debris flows in near-real time with a good reliability.

However, open questions remain about the possibility to infer source characteristics and event magnitude from recorded geophysical signals. This requires theoretical source models of elastic energy radiated both in the ground, in the form of seismic waves, and in the atmosphere, in the form of infrasound.  Seismic waves are believed to be generated by both large sediment particles impacts on the channel bed and by turbulent structures within the debris flow. Infrasound is instead believed to be generated by standing waves at the free surface of the flow, but their source processes are not yet fully understood.

Here we present preliminary results of a study performed at the Illgraben catchment (Switzerland), in the 2017-2019 period, combining infrasound and seismic signals with direct in-torrent measurements of flow depth and velocity. Seismic and infrasound signals are analyzed using both spectral analysis and array techniques, in order to achieve an improved understanding of the dynamics of the source mechanisms of the two wavefields. Comparison with in-situ measurements is used to extrapolate empirical relationships between signal features, e.g. amplitude, spectral content or waveform characteristics of both seismic signals and infrasound, and flow characteristics.

The results obtained will possibly be used to develop an efficient monitoring system for remote detection and the early warning of debris flows using seismic signals and infrasound generated by the process.
Mapping of Arctic Wetlands with Threats of Future Permafrost Thaw
Authors: Jonsson Elisie , Ghajarnia Navid , Hugelius Gustaf , Kalantari Zahra
Published: March 2020

The Arctic is warming twice as fast as the rest of the globe, causing changes to Arctic ecosystems. While wetlands in the Arctic provide many ecosystem services with both local and global importance, still more knowledge is needed on the location and state of Arctic wetlands to successfully focus adaptation and mitigation efforts. To understand the links between temperature changes and changes to Arctic wetlands, this study includes the use of spatial tools to map existing wetlands and model permafrost response to temperature changes, highlighting wetland areas with risks of future changes. Using available high-resolution wetland databases together with soil wetness and soil type data, a wetland map covering the Arctic was created. Based on existing relationships between climate and observed permafrost, future changes in permafrost were modeled using projected mean annual temperature from the HadGEM2-ES climate model outputs for the RCP2.6, 4.5 and 8.5 scenarios and for years 2050, 2075 and 2100. We found that the Arctic contains a large number of wetlands and a very significant number of these exist on permafrost. As substantial permafrost thaw is projected, the extent and properties of wetlands will shift, and local/regional increases or decreases in wetland extent will depend on variables such as soil type. These changes could lead to serious local consequences, such as threats to food and water security, changes in distribution and demographics of animal and plant species, and losses and disruptions of infrastructure. The findings of this study highlight vulnerable areas that need extra attention in terms of adaptation and mitigation efforts to limit the likely impacts of projected changes, given the current trends.

Keywords: Arctic wetland, spatial modeling, permafrost, climate change
Assessing lahar hazards at Cotopaxi volcano (Ecuador) controlled by volcanic eruptions and glacier retreat
Authors: Frimberger Theresa , Petry Franziska , Krautblatter Michael
Published: March 2020

Lahars rank as one of the most destructive hazards at Cotopaxi volcano (5897 m asl) due to the presence of a massive glacier cap, the frequency of eruptions and the high population density in the surrounding, potentially inundated valleys. In 1877, Cotopaxi experienced the last major VEI 3-4 eruption, producing syneruptive lahars of 60-100 million m3 that travelled hundreds of km downstream.  Few lahar simulations based on empirical or fluid dynamic approaches exist for Cotopaxi, but here we introduce a calibrated numerical debris flow model capable of reproducing confluence and erosivity of flows.

In this study, we back-calculate the well documented 1877 lahar event using the 2D debris flow model RAMMS, which is based on the Voellmy-Salm friction approach and includes an entrainment algorithm. We first evaluate the sensitivity and range of possible model input parameters by systematically varying model inputs for release volume, density and frictional resistance (Coulomb type friction μ [-] and turbulent friction ξ [ms-2]). Supported by a probabilistic analysis, we find that a choice of historical and field-derived calibration metrics of the 1877 lahar event along the northern lahar trajectory can well constrain most likely input parameters for frictional resistance. Our results show that modelling large-scale primary lahars at Cotopaxi is strongly controlled by very small values for Coulomb friction μ (0.005-0.015). Finally, we apply the calibrated model to typical eruption scenarios of Cotopaxi (VEI 1 to >4) in order to enable a realistic lahar hazard representation.

Considering the rapid rise of the equilibrium-line altitude of tropical Andean glaciers together with reports on secondary lahars at the eastern flank of Cotopaxi without any clear trigger, we hypothesize a process-based link between the two phenomena.  Geoelectrical and refraction seismic field surveys near the glacier margin (5000- 5300 m asl) have been conducted in order to gain a better understanding of the structure, conditions and degree of freezing of the subsurface, which is dominated by loose pyroclastic material and interbedded lava layers. The tomography results are highlighted within the concept of permafrost degradation and accompanied material weakening as potential triggering mechanism for secondary lahars.

Here we show 1) a carefully calibrated numerical lahar model at Cotopaxi capable of reproducing previously non-respected effects such as confluence, erosion reach and propagation speed, and 2) first measurements addressing the role of glacier retreat on the formation of secondary lahars. Our results contribute to the multi-hazard risk assessment in the RIESGOS project funded by the German Ministry of Education and Research.
The superiority of circular economy solutions in the main sectors of an innovative and prospering economy – a case study from Iceland
Authors: Finger David C. , Svavarsson Halldór G. , Björnsdóttir Bryndís , Sævarsdóttir Guðrún A. , Lea Böhme Lea
Published: March 2020

Circular economy solutions reuse and upcycle waste streams in order to minimize the use of resources and mitigate the creation of waste and emissions. Accordingly, circular economy solutions are an essential tool to tackle the imminent challenges of depleting resources and the emerging environmental crisis. In this presentation, we explore the circular solutions for resource recovery in waste streams in a country with one of the highest Gross Domestic Product (GDP) and Human Development Index (HDI) in Europe, Iceland. The economy of Iceland is mainly based on renewable energy, fishery, farming, metallurgy, and tourism. To assess the benefits of circular economy solutions we examine four relevant case studies from the following industrial sectors in Iceland: i) a geothermal energy plant, ii) fisheries, iii) domestic waste processing and iv) aluminium production. By describing the processes, the opportunities and the market potential of the circular economy solutions in the four case studies we identify the superiority of circular recovery of resources in a modern society. The results reveal that the recovery of resources reduces the environmental impacts, increases the economic output and enhances the resilience of the local economy. While our results are based on the examples in Iceland the described processes of resource recovery can be applied in any other country with similar resources. We conclude that the presented circular solutions could lead to a more sustainable world while preserving vital resources for the next generations.