bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of the performance of spatial landslide prediction with TRIGRS1D and SCOOPS3D models and parameter optimization: application to the Oltrepò Pavese
Authors: Palazzolo Nunziarita , Peres David J. , Bordoni Massimiliano , Meisina Claudia , Creaco Enrico , Cancelliere Antonino
Published: March 2020

Physically based models based on the combination of hydrological and slope stability models are important tools in spatial and temporal prediction of landslides, since they can be used for hazard mapping as an aid for land planning. In many applications, hydrological models are combined with very simple infinite slope stability analysis, given that multi-dimensional analysis is more computationally demanding. Only a few studies have attempted to apply such algorithms to the catchment scale. Thus, there is a need for more studies on this issue, also to understand the real advantages of applying multi-dimensional slope stability analysis in comparison with the one-dimensional. 

This study aims to compare the performance of two different forecasting models, namely the infinite slope and the three-dimensional stability analysis by SCOOPS3D (Software to analyze three-dimensional slope stability throughout a digital landscape), a very efficient model proposed by USGS to be applied to the catchment scale, which has seldom been applied so far in the literature. In particular, TRIGRS (Transient Rainfall Infiltration and Grid-Based Regional Slope-stability Model) is used for hydrological analysis.  Then the resulting pressure head field is used first as input to the infinite slope stability model embedded into TRIGRS program itself and then as input to SCOOPS3D. To calibrate the terrain stability-related parameters of either piece of software, a multi-objective optimization is proposed in this work to maximize the model predictability performance, in an attempt to optimize ROC performance statistics, i.e. to maximize the true positive rate while simultaneously minimizing the false positive rate.

The approach was applied to a real case study, a catchment in the Oltrepò Pavese (northern Italy), in which the areas of triggered landslides were accurately monitored during an extreme rainfall on 27-28 April, 2009, featuring 160 mm in 48 h. Compared to other works in the scientific literature, in which only a generic point of location of landslides was known, the present work benefits from the availability of a detailed landslide inventory containing observed landslide shapes.

The results point out the significantly better performance of  SCOOPS3D, in comparison with the infinite slope stability. Though SCOOPS3D seems to overestimate landslide prone areas, the 3D method is more realistic than the 1D method as far as the slip surface definition is concerned. Therefore, the proposed methodology, lying in the use of SCOOPS 3D with optimized parameters, can be a helpful tool for providing multiple landslide hazard maps for planning.
Cosmogenic burial dating of in cave-deposited alluvium: unravelling long-term incision rates and complex speleogenesis in multi-level cave systems
Authors: Rixhon Gilles , Bourlès Didier L. , Braucher Régis , Peeters Alexandre , Demoulin Alain
Published: March 2020

Multi-level cave systems record the history of regional river incision in abandoned alluvium-filled phreatic passages which, mimicking fluvial terrace sequences, represent former phases of fluvial base-level stability. In this respect, cosmogenic burial dating of in cave-deposited alluvium (usually via the nuclide pair 26Al/10Be) represents a suitable method to quantify the pace of long-term river incision. Here, we present a dataset of fifteen 26Al/10Be burial ages measured in fluvial pebbles washed into a multi-level cave system developed in Devonian limestone of the uplifted Ardenne massif (eastern Belgium). The large and well-documented Chawresse system is located along the lower Ourthe valley (i.e. the main Ardennian tributary of the Meuse river) and spans altogether an elevation difference exceeding 120 m.

The depleted 26Al/10Be ratios measured in four individual caves show two main outcomes. Firstly, computed burial ages ranging from ~0.2 to 3.3 Ma allows highlighting an acceleration by almost one order of magnitude of the incision rates during the first half of the Middle Pleistocene (from ~25 to ~160 m/Ma). Secondly, according to the relative elevation above the present-day floodplain of the sampled material in the Manants cave (<35 m), the four internally-consistent Early Pleistocene burial ages highlight an “anomalous” old speleogenesis in the framework of a gradual base-level lowering. They instead point to intra-karsting reworking of the sampled material in the topographically complex Manants cave. This in turn suggests an independent, long-lasting speleogenetic evolution of this specific cave, which differs from the per descensum model of speleogenesis generally acknowledged for the regional multi-level cave systems and their abandoned phreatic galleries. In addition to its classical use for inferring long-term incision rates, cosmogenic burial dating can thus contribute to better understand specific and complex speleogenetic evolution.
Spatio-temporal survey of the coastal carbonate system offshore Lebanon-Levantine Mediterranean Sea
Authors: Hassoun Abed El Rahman , Fakhri Milad , Habib Majd , Ouba Anthony , Jemaa Sharif , Mahfouz Céline , Jaber Houssein , Ghanem Abeer , Tannous Mariam , El Kheir Mohamad
Published: March 2020

The coastal carbonate system regulates the pH of the coastal waters and controls the circulation of CO2 between land-sea interfaces and open sea system. In the context of the ELME (Evaluation of the Lebanese Marine Environment: A multidisciplinary study) project, a seasonal survey of the carbonate system has been started in 2019 through the sampling of 3 different transects starting from the coast towards the open sea, offshore two Lebanese cities (Beirut and Tyre) to evaluate the spatio-temporal variations of this system in coastal areas. The carbonate chemistry is being studied by measuring both total alkalinity (AT) and total dissolved inorganic carbon (CT), together with other critical parameters in coastal ecosystems such as temperature, salinity, pH, dissolved oxygen, nutrients (phosphates, nitrates, nitrites, silicates), and chlorophyll a. The preliminary results show that the highest carbonate system inventories (2546.4 and 2266 µmol kg-1 for AT and CT respectively) were measured in transects influenced by discharges of dumpsite and port areas (offshore Beirut) where positive and significant correlations (p << 0.005) have been recorded with nutrients, particularly with nitrites (> 10 µmol kg-1). Furthermore, TrOCA approach was used to estimate the anthropogenic CO2 concentrations (CANT) below the mixed layer depth. The results demonstrate that all waters in both studied areas are contaminated by CANT, even the deep ones (> 400 m) located in the furthest monitored station, with values greater than 70 µmol kg-1. This fact raises concerns about the effects of such relatively high CANT concentrations on coastal organisms therein. This work presents the preliminary results of an ongoing study. The continuity of this project will help to assess the relationship between land-based anthropogenic pressures and the coastal biogeochemistry in a changing Eastern Mediterranean Sea.
The geothermal potential of sedimentary basins – case study for Berlin, Germany
Authors: Bott Judith , Frick Maximilian , Koltzer Nora , Cacace Mauro , Lewerenz Björn , Schneider Michael , Scheck-Wenderoth Magdalena
Published: March 2020

In this case study a method to estimate the geothermal potential is presented for the capital city of Berlin, Germany. Therefore, it is essential to know the temperature distribution in the subsurface which has been studied intensively in the past.
Building on this knowledge, newly available subsurface temperature predictions have been used along with updated geometries and geophysical properties as input data for the application case of hydrothermal doublets and their comparison to earlier realizations. This shows how considering more complex geometries, boundary conditions and processes in numerical 3D thermohydraulic simulations leads to significant changes in the predicted geothermal potential and the associated controlling factors. The model area is part of the Northeast German Basin which consists of a thick sequence (up to 10 km) of differently consolidated sedimentary deposits. This sequence is made up of alternating aquifers and aquitards, wherein several encompass promising targets for different geothermal application scenarios. Namely these include the Jurassic, Middle Buntsandstein and the Sedimentary Rotliegend aquifers. The former two of these reservoirs depict a complex geometry (mainly due to deeper salt movements) leading to a wide range of predicted temperatures, while the latter (situated below the salt) has a more homogenous topography and temperature distribution. This is also connected to the efficacy of different heat transport processes at different depths.
The predicted heating power is therefore also distributed heterogeneously and reaches maxima as large as 1.25 MWth for the Jurassic, 10 MWth for the Middle Buntsandstein and 2.2 MWth for the Sedimentary Rotliegend. The models further show that the geothermal potential (or the heating power) of a hydrothermal doublet is controlled by more than merely the reservoir temperature but also the producible mass flux, which in turn depends highly on the reservoir transmissivity. Due to the high variability of predicted geothermal potentials, different utilization scenarios should be investigated in future studies, such as aquifer thermal energy storage or low enthalpy geothermal utilizations.
Aviso+: what’s new on the reference portal in satellite altimetry?
Authors: Soudarin Laurent , Mertz Françoise , Rosmorduc Vinca , Schgounn Catherine , Guinle Thierry , Birol Florence , Niño Fernando
Published: March 2020

Aviso (Archiving, Validation and Interpretation of Satellite Oceanographic data) is a service set up by CNES to process, archive and distribute data and products from altimetry satellite missions. Its portal AVISO+ (www.aviso.altimetry.fr) is the entry point to freely access more than 40 products from CNES (Centre National d'Etudes Spatiales) and CTOH (Center for Topographic studies of the Ocean and Hydrosphere) not only for ocean-oriented applications but also for hydrology, coastal, ice applications. In addition, the website proposes information (handbooks, use case, outreach material, …) to discover the products and their use. New products are regularly added to the catalogue, whether they are operational or demonstration products. For example, in 2019, the catalogue has been enriched with L2P level products from the Copernicus Sentinel-3A & 3B missions, the new version of the Mean Dynamic Topography CNES/CLS 2018, the mesoscale Eddy Trajectory Atlas in Near Real Time, several datasets of along-track and gridded SSALTO/DUACS experimental products, and some others. In 2020, some products of the CFOSAT (China-France Oceanography SATellite) mission devoted to the monitoring of ocean surface winds and waves, as well as CTOH ice and snow products will be available via Aviso+.

This presentation gives an overview of available products and services. We also present here all the recent novelties, and those to come in 2020.
Seasonal active landsliding and hillslope activity in the southern Central Andes of NW Argentina
Authors: M.Aref Mohammad , Bookhagen Bodo , T. Smith Taylor , R. Strecker Manfred
Published: March 2020

The eastern Central Andes of northwestern Argentina is characterized by a steep topographic gradient with elevations ranging from 1000m in the foreland to more than 6000m in the eastern Andean Cordillera. This setting furthermore shows high topographic relief with deeply incised river valleys that are frequently impacted by strong rainfall events driven by the South American monsoon. Additionally, a strong vegetation cover contrast from dense coverage in the low elevation foreland to sparse coverage at high elevation defines the environmental gradient in this area. This area is impacted by several types of hillslope instabilities and landsliding: at some high elevations above 5000m hillslope instability are related to solifluction processes, whereas shallow and deep seated landsliding affect geologically preconditioned areas.

Here we use a combination of different radar sensors and wavelengths to describe the 3D deformation signal of instable hillslopes: TerraSAR-X, Sentinel-1, and ALOS2. To mitigate the tropospheric delay from InSAR measurements, phase-based and weather model approaches are applied to improve the spatial and temporal variations of displacement signals.  We use persistent and small baseline subsets (SBAS) category of distributed scatterer approaches to derive deformation fields and we invert for 3D deformation fields using several look angles in combination with GNSS data under different assumptions including that the horizontal component has a motion parallel to the downhill slope. We analyze Line-of-sight (LOS) time series and combine deformation fields with temperature and rainfall measurements to better understand driving forces of high-elevation hillslope instabilities We describe two deep-seated landslides with downslope velocities exceeding 5-10 cm/yr and we exploit image-cross correlation techniques of optical data to monitor seasonal and inter-annual changes. The periodic changes of InSAR deformation and temperature time series show freeze-thaw processes of the active layer thickness of the permafrost areas at elevations exceeding 5000m. We document that deep-seated, fast moving landslides are related to geologic preconditioning. The combination of SAR and optical approaches helps to describe hillslope regimes in steep and difficult to access terrain.
Diabatic generation of negative potential vorticity and its impact on the jet stream
Authors: Harvey Ben , Methven John
Published: March 2020

Localised regions of negative potential vorticity (PV) are frequently seen on the equatorward flank of the upper-tropospheric jet streams in analysis and forecast products. Their positioning, on the anticyclonic side of the jet and often close to the jet core, suggest they are associated with an enhancement of jet stream maximum winds. Given that PV is generally positive in the northern hemisphere and is conserved under adiabatic conditions, the presence of negative PV is indicative of recent diabatic activity. However, little is understood on the mechanisms for its generation and subsequent lifecycle.

In this study, aircraft measurements from a recent field campaign are used to provide direct observational evidence for the presence of negative PV on the anticyclonic side of an upper-tropospheric jet. Theory is then developed to understand the process by which PV can turn negative. The key ingredient is diabatic heating in the presence of vertical wind shear, and the resulting PV anomalies are shown to always result from a flux of PV directed 'down the isentropic slope'. This explains why, for the typical situation of heating in a warm conveyor belt, negative PV values appear on the equatorward side of the upper-tropospheric jet stream close to the jet core. These ideas are illustrated with a semi-geostrophic model and the processes responsible for the observed negative PV are explored using an operational forecast model with online PV tracer diagnostics.

The diabatic influence on jet stream winds and shear is of interest because it is pertinent to the predictability of extreme jet stream events and associated flight-level turbulence, and is crucial to the propagation of Rossby waves at tropopause level, development of mid-latitude weather systems and their subsequent impacts at the surface.
Induced Fault Reactivation and Hydraulic Diffusivity Enhancement : Insights from Pressure Diffusion Inversion in Laboratory Injection Tests
Authors: Almakari Michelle , Chauris Hervé , Passelègue François , Dublanchet Pierre
Published: March 2020

Understanding how the permeability of a fault evolves during injection induced fault reactivation process is of great interest. The interactions between fluids and faults can be complex, as the confining pressure, effective stress and shear slip can affect the hydro-mechanical properties of the fault. The relationship between induced slip (reactivation) front and fluid front requires a better understanding of what controls hydraulic diffusivity as well.
In this study, we investigate shear induced fluid flow and permeability enhancement during fracture shearing. We used a series of laboratory injection reactivation tests on saw cut Andesite rock sample, under triaxial conditions, at different confining pressures (30, 60 and 95 MPa). The sample was connected to two pressure sensors, at two opposite locations of the fault, and equipped by strain gauges along strike.
We thus propose a numerical method, in the context of deterministic and probabilistic inversion approaches, that allows to estimate the temporal evolution of the effective hydraulic diffusivity (and its associated uncertainties) of an experimental fault throughout an injection test, using the pressure history at two points on the fault.
The numerical method was able to reproduce the experimental data for a wide time range of the different experiments. The hydraulic diffusivity was found to largely depend on the confining pressure and to increase (by one order of magnitude) throughout the injection experiment with the reduction of the mean effective stress acting along the fault plane. As well, the shear slip was observed to have an effect on the hydraulic diffusivity evolution. Instantaneous short term diffusivity enhancement accompanied slip events with large slip velocities, while long term increases accompanied slow slip events.
First eddy covariance flux measurements of gaseous elemental mercury over a grassland
Authors: Osterwalder Stefan , Eugster Werner , Feigenwinter Iris , Jiskra Martin
Published: March 2020

Direct measurements of the net ecosystem exchange (NEE) of gaseous elemental mercury (Hg0) are crucial to improve our understanding of global Hg cycling and ultimately Hg exposure in humans and wildlife. The lack of long-term, ecosystem-scale measurements causes large uncertainties in Hg0 flux estimates. Today it remains unclear whether terrestrial ecosystems are net sinks or sources of atmospheric Hg0. Here, we present the first successful eddy covariance NEE measurements of Hg0 over natural, low-Hg soils (41 - 75 ng Hg g-1 topsoil [0-10 cm]) at a managed grassland site in Chamau, Switzerland. We present a detailed validation of the eddy covariance technique for Hg0 based on a Lumex mercury monitor RA-915AM. The flux detection limit derived from a zero-flux experiment in the laboratory was 0.22 ng m-2 h-1 (maximum) with a 50 % cut-off at 0.074 ng m-2 h-1. The statistical estimate of the Hg0 flux detection limit under real-world outdoor conditions at the site was 5.9 ng m-2 h-1 (50 % cut-off). Based on our analysis we give suggestions to further improve the precision of the system and pinpoint challenges and interferences that occurred during the 34-day pilot campaign in summer 2018. The data were obtained during extremely hot and dry meteorological conditions. We estimated a net summertime grassland-atmosphere Hg0 flux from -0.6 to 7.4 ng m-2 h-1 (range between 25th and 75th percentiles). The measurements revealed a distinct diel pattern with lower nighttime fluxes (1.0 ng m-2 h-1) compared to daytime fluxes (8.4 ng m-2 h-1). Drought stress during the campaign induced partial stomata closure of vegetation leading to a midday depression in CO2 uptake, which did not recover during the afternoon. We suggest that partial stomata closure dampened Hg0 uptake by vegetation as well, resulting in a NEE of Hg0 dominated by soil emission. The new Eddy Mercury system seems suitable to complement existing research infrastructures such as ICOS RI in Europe or NOAA Observing Systems in the US built to calculate greenhouse gas balances with direct Hg0 deposition and emission measurements. We anticipate our Eddy Mercury system to improve knowledge about Hg cycling between ecosystems and the atmosphere and to challenge model simulations on a regional and global scale.
Constraint of GIA in Northern Europe with Geological RSL and VLM Data
Authors: Simon Karen , Riva Riccardo
Published: March 2020

In this study, we focus on better constraint of the long term glacial isostatic adjustment (GIA) signal at present-day, and its role as a contributor to total present-day rates of change. The main study area extends from the coastal regions of northern Europe to Scandinavia. Both Holocene relative sea level (RSL) data as well as vertical land motion (VLM) data are incorporated as constraints in a semi-empirical GIA model. Specifically, 70 geological rates of GIA-driven RSL change are inferred from Holocene data; peak RSL fall is indicated in central Scandinavia and the northern British Isles where past ice sheets were thickest, RSL rise is indicated in the southern British Isles and along the northern European coastline. Rates of vertical land motion from GPS at 108 sites provide an additional measure of regional GIA deformation. Within the study area, the geological RSL data complement the spatial gaps of the VLM data and vice versa; both datasets are inverted in a semi-empirical GIA model to yield updated estimates of regional present-day GIA deformations. A regional validation is presented for the North Sea, where the GIA signal may be complicated by lateral variations in Earth structure and existing predictions of regional and global GIA models are discrepant. The model validation in the North Sea region indicates that geological data are needed to fit independent estimates of GIA-related RSL change inferred from tide gauge rates, suggesting that the geological rates provide an important additional constraint of present-day GIA.
High Andean Wetlands, climate change and ecosystem services – What do we know?
Authors: Otto Marco , Maldonado Fonken Mónica , Baiker Jan , Gibbons Richard
Published: March 2020

Research in high mountain regions has been intensified over the last decade due to e.g. increased concerns about how climate change might affect those regions containing fragile and often remote ecosystems. Wetlands in high mountain regions belong to a kind of vulnerable ecosystems, which have been studied also in the Andes. We systematically gathered information derived from literature on wetland types within the tropical part of high Andean grasslands and shrublands (above tree line) also known as Páramo (northern part) and Puna (southern part). We applied a keyword search on two major global citation database resulting in 230 records from 1979 until present. Here, we found over a hundred peer-reviewed publications focused on High Andean Wetlands providing information on wetland types and geographic references of their respective study sites. Most studies were conducted within the Puna and were related to peatlands. High Andean Wetlands are often seen as providers for certain ecosystem services (ES). Results indicate that current knowledge is mostly based on short-term studies at single-site scale. Thus, not all ES that are assumed to be related to High Andean Wetlands are sufficiently documented by scientific work. Therefore, we present preliminary results of currently conducted studies addressing ES provided by High Andean Wetlands fostering our knowledge and closing still existing knowledge gaps.
Peatland restoration age (Scotland, UK) can be better reproduced by a classification model based on Sentinel-2 than with high resolution aerial imagery
Authors: Artz Rebekka , Ball Jonathan , Smart Catherine , Donaldson-Selby Gillian , Cowie Neil , Hancock Mark , Klein Daniela , Gimona Alessandro
Published: March 2020

Damage to peatland globally causes significant contributions to the current net greenhouse gas emissions and pose a further future risk as such damaged peatlands are vulnerable to future climatic stress. Globally, peatland restoration efforts are rapidly increasing in scale as natural climate solutions, yet relatively little effort has been it into effective monitoring of landscape scale restoration projects. We developed a classification model that uses remote observations (Sentinel-2 or national scale aerial imagery from Getmapping) to detect restoration efficacy by training it against a dataset from a chronosequence of spatially collocated peatland restoration sites that had previously been converted to plantation forestry. The Sentinel-2 based model greatly outperformed the aerial imagery-based model (RGB and IR, 25 and 50 cm, respectively). Adding slope to the classification improved kappa by less than 0.02. Prediction of the starting (forestry) and target (restored) state was very robust, and both recent and the oldest restoration sites were spatially well predicted. The main model uncertainties lie with sites of intermediate age, where on-the-ground restoration trajectories based on vegetation composition also differ the most, and with sites where additional layers of management after the initial restoration management have been applied.
Low Frequency Radar (LFR) on the JUVENTAS CubeSat for HERA / ESA mission
Authors: Herique Alain , Plettemeier Dirk , Kofman Wlodek , Rogez Yves , Goldberg Hannah
Published: March 2020

The Low Frequency Radar (LFR) on the JUVENTAS CubeSat for HERA / ESA mission to Didymos Binary Asteroid is a unique opportunity to perform direct measurements of its internal structure and regolith. LFR has been developed to fathom asteroid from a small platform. This instrument is inherited from CONSERT/Rosetta and has been redesigned in the frame of the AIDA and HERA ESA mission.

Onboard JUVENTAS, LFR is operating in monostatic mode to probe down to the first hundreds of meters into the subsurface and to achieve a full tomography of the Didymos' moonlet. Direct observations of the internal structure of asteroids can solve still open basic questions like: Is the body a monolithic piece of rock or a rubble-pile? How high is the porosity? What is the typical size of the constituent blocks? Are these blocks homogeneous or heterogeneous? How is the regolith covering its surface constituted?

The low frequency aboard the Juventas CubeSat will contribute to the solution of these open and for planetary defense crucial questions.
- The first LRF objective is the characterization of the moonlet interior, to identify internal structure and to analyze the size distribution and heterogeneity of constitutive blocks from sub metric to global
- The second objective is the estimation of average permittivity and mapping of its spatial variation especially in the crater area.
- The same characterization applied to the main of the binary system is among secondary objectives.
- Supporting shape modeling and determination of the dynamical state by radar ranging is a further secondary objective.

This paper will present the instrument concept and measurement strategy, its performances and the expected science return.
Origin and metamorphic reworking of the Buca della Vena Tl-rich orebody (Alpi Apuane, Italy)
Authors: Vezzoni Simone , Pieruccioni Diego , Dini Andrea , Molli Giancarlo , Biagioni Cristian
Published: March 2020

The origin and evolution of an orebody hosted in metamorphic terrane is a prime topic in economic geology because they have implications on exploration as well as on related potential geo-environmental health hazards. The Alpi Apuane orebodies has long been known; however, their ore genesis and the relationships with the Apenninic age deformation and metamorphism is still a matter of debate. Indeed, they are still an interesting field of research, as proved by the recent discovery of a remarkable Tl anomaly associated to the baryte ± pyrite ± Fe-oxides ores of southern Alpi Apuane, northern Tuscany, Italy [1]. The present work reports a new detailed field and underground geological-structural investigation, performed from cartographic- to microscopic-scale, integrated by available drill-logs data, of one of these Tl-rich orebodies - the Buca della Vena ore.

The present study gives new insights on some aspect of the ore-forming events and discusses previous interpretations. According to our investigations, the ore settings were acquired during successive geological events related to an early hydrothermal-magmatic phase, likely of Permian age, and to the more recent Apenninic deformations. We suggest that the proto-ore was produced by hydrothermal activity related to the post-Variscan magmatic cycle (documented by the Permian age “Fornovolasco metarhyolite” Fm [2]), causing ore-formation, tourmalinization and hydrothermal alteration halo in the Cambrian-Lower Ordovician phyllites host-rocks. In our model, the ores were then partially exhumed suffering supergene alteration with development of minor Fe-oxides sedimentary mineralizations during the upper Norian-Hettangian. Finally, the previous hydrothermal and sedimentary ores, along with the host-rocks, were involved in the Apenninic orogenesis, and were recrystallized, and partially remobilized acquiring the current mineralogical, textural, and structural settings.

References:

[1] Biagioni, C., D’Orazio, M., Vezzoni, S., Dini, A., Orlandi, P., 2013. Mobilization of Tl-Hg-As-Sb-(Ag,Cu)-Pb sulfosalt melts during low-grade metamorphism in the Alpi Apuane (Tuscany, Italy). Geology, 41, 747-750.

[2] Vezzoni, S., Biagioni, C., D’Orazio, M., Pieruccioni, D., Galanti, Y., Petrelli, M., Molli, G., 2018. Evidence of Permian magmatism in the Alpi Apuane metamorphic complex (Northern Apennines, Italy): New hints for the geological evolution of the basement of the Adria plate. Lithos, 318-319, 104-123.
Rossby wave breaking through the 21st century in a global climate model
Authors: Bowley Kevin , Gervais Melissa
Published: March 2020

Rossby wave breaking on the dynamic tropopause (DT) occurs when synoptic-scale Rossby waves become highly amplified and undergo a breaking process.  This process can result in significant meridional transport of air masses resulting and intrusions of low latitude air poleward, high latitude air equatorward, or a combination of the two.  The ensuing modification of the troposphere and lower stratosphere in response to such events have been areas of considerable research due to their potential impacts on both high- and low-frequency mid- and high-latitude variability.  Furthermore, the processes and feedbacks associated with these events can result in notable changes to the jet structure and are frequently associated with atmospheric river events amongst other phenomena.  As such, the potential impacts of future changes in these events make them of considerable interest for identifying and studying in global climate model (GCM) simulations. 

Here, we apply a Rossby wave breaking identification scheme to three sets of 25-member Community Earth System Model simulations with prescribed sea surface temperature and sea ice conditions over the historical period (2010-2019), mid-Century (2050-2059) and late-Century (2090-2099).  This dataset represents a unique opportunity to study Rossby wave breaking processes in future climate simulations on a dynamically evolving surface rather than the more common pressure levels or isentropic levels as the DT is calculated for each of the CESM members.  Both anticyclonic and cyclonic Rossby wave breaking events are identified and tracked.  Events modeled in the historical period are compared to existing reanalysis data for the same period to explore the ability of the CESM model in this configuration to reproduce these events accurately.  Furthermore, the three periods of interest are examined to determine changes in the locations of Rossby wave breaking as well as the dynamic and thermodynamic characteristics of composited events. 
3D Architecture and Plio-Quaternary evolution of the Paola Basin: Insights into the Forearc of the Tyrrhenian-Ionian Subduction System
Authors: Corradino Marta , Pepe Fabrizio , Bertotti Giovanni , Picotti Vincenzo , Monaco Carmelo , Nicolich Rinaldo
Published: March 2020

Fore-arc basins form structurally in response to a variety of subduction zone processes. The sedimentary infill records the tectono-stratigraphic evolution of the basin, and thus, provides information on the dynamic of the fore-arc region. Using seismic reflection profiles and bathymetric data, we analysed the stratigraphy and tectonics of the Paola Basin, deciphering the tectono-sedimentary mechanisms that acted in the forearc of the Tyrrhenian‐Ionian subduction system during the Plio-Quaternary. The Paola Basin is a NNW-SSE trending syncline, bounded by the Coastal Chain to the east and a regional-scale anticline, here called Paola Anticline, to the west. There are no major normal faults bordering the basin. It hosts up to 5.2 km thick Plio-Quaternary deposits, most of them supplied from Apenninic/Sila entry points and transported by longshore currents. The total subsidence reaches the value of ∼5 km. The sedimentary load varies from 60% to 75% of the total subsidence. The Pliocene to Lower Pleistocene sedimentary infill of the syncline displays a strata growth geometry consistent with a continuous rotation of the eastern limb of the Paola Anticline. Crustal folding is the mechanism that better explains the lack of significant normal faults bordering the Paola Basin, its tectonic subsidence and the uplift of the Paola Anticline. During the Late Pliocene - Early Pleistocene, contractional deformation continued, and also strike-slip movements affected both the Paola Anticline and the eastern sector of the basin. This resulted in the growth of the central sector of the Coastal Chain, leading to the definition of the Paola and Crati basins, previously connected in a larger proto basin. Also, strike-slip faults with associated releasing and restraining bends formed in the hinge zone of the Paola Anticline. The bathymetric expression of the strike-slip zone consists of structural highs and depressions that overall form the Paola Ridge. The development of strike-slip tectonics is associated to the trench-parallel component of the upper plate motion occurring in the oblique subduction setting. The growth of the Paola Anticline and Paola Basin was coeval with the opening of the Vavilov and Marsili back arc basins. Thus, extensional and contractional tectonics spatially coexisted along sectors of the upper plate of the Tyrrhenian-Ionian subduction system from Early Pliocene to Early Pleistocene. Since the Middle Pleistocene, the growth of the Paola Anticline and Paola Basin came to an end, and extensional tectonics controlled the evolution of the forearc region.
Automated image classification of outlet glaciers in Greenland using deep learning
Authors: Marochov Melanie , Carbonneau Patrice , Stokes Chris
Published: March 2020

In recent decades, a wealth of research has focused on elucidating the key controls on the mass loss of the Greenland Ice Sheet and its response to climate forcing, specifically in relation to the drivers of spatio-temporally variable outlet glacier change. Despite the increasing availability of high-resolution satellite data, the time-consuming nature of the manual methods traditionally used to analyse satellite imagery has resulted in a significant bottleneck in the monitoring of outlet glacier change. Recent advances in deep learning applied to image processing have opened up a new frontier in the area of automated delineation of glacier termini. However, at this stage, there remains a paucity of research on the use of deep learning for image classification of outlet glacier landscapes. In this contribution, we apply a deep learning approach based on transfer learning to automatically classify satellite images of Helheim glacier, the fastest flowing outlet glacier in eastern Greenland. The method uses the well-established VGG16 convolutional neural network (CNN), and is trained on 224x224 pixel tiles derived from Sentinel-2 RGB bands, which have a spatial resolution of 10 metres. Based on features learned from ImageNet and limited training data, our deep learning model can classify glacial environments with >85% accuracy. In future stages of this research, we will use a new method originally developed for fluvial settings, dubbed ‘CNN-Supervised Classification’ (CSC). CSC uses a pre-trained CNN (in this case our VGG16 model) to replace the human operator’s role in traditional supervised classification by automatically producing new label data to train a pixel-level neural network classifier for any new image. This transferable approach to image classification of outlet glacier landscapes permits not only automated terminus delineation, but also facilitates the efficient analysis of numerous processes controlling outlet glacier behaviour, such as fjord geometry, subglacial plumes, and supra-glacial lakes.
OpenAltimetry: Key Elements of Success in Visualizing NASA's Spaceborne LiDAR Data
Authors: Khalsa Siri Jodha , Borsa Adrian , Nandigam Viswanath , Phan Minh
Published: March 2020

NASA’s spaceborne laser altimeter, ICESat-2, sends 10,000 laser pulses per second towards Earth, in 6 separate beams, and records individual photons reflected back to its telescope. From these photon elevations, specialized ICESat-2 data products for land ice, sea ice, sea surface, land surface, vegetation and inland water are generated. Altogether these products total nearly 1 TB per day, which poses data management/visualization challenges for potential users. OpenAltimetry, a browser-based interactive visualization tool, was built to provide intuitive access to data from ICESat-2 and its predecessor mission (ICESat). It emphasizes ease of use and rapid access for expert and non-expert audiences alike. The initial design choices and subsequent user-informed development have led to a tool that has been enthusiastically received by the ICESat-2 Science Team, researchers from various disciplines, and the general public. This presentation will highlight the elements that led to OpenAltimetry’s success.
Attributing coastal flood damages to sea level rise for recent flood events
Authors: Treu Simon , Mengel Matthias , Frieler Katja
Published: March 2020

Sea level rise increases extreme water levels and thus the flood losses from storm surge events. While it is still difficult to estimate the influence of climate change on single storms, the influence of anthropogenic climate change on sea level rise is evident. We here aim to quantify the fraction of damages caused by sea level rise for a set of flood events of the last decade. Flood-extents and the spatial distribution of damages are reconstructed from openly available data-sources. We construct counterfactual flood extents for each event by a counterfactual sea level as it would have been in a world without climate change. As we are particularly interested in losses in poorer countries that often lack high resolution data such as LiDAR based elevation maps or tide-gauge records, our methodology is transferable between regions, building on global and open data. Depending on the study site, we detect a difference between observed and counterfactual damages though uncertainties remain high. Data availability and data detail remain a major restriction.
Hydronomeas 2020: Open-source decision support system for water resources management
Authors: Karavokiros George , Nikolopoulos Dionysios , Manouri Stavroula , Efstratiadis Andreas , Makropoulos Christos , Mamassis Nikos , Koutsoyiannis Demetris
Published: March 2020

Over the last 30 years, numerous water resources planning and management studies in Greece have been conducted by using state-of-the-art methodologies and associated computational tools that have been developed by the Itia research team at the National Technical University of Athens. The spearhead of Itia’s research toolkit has been the Hydronomeas decision support system (which stands for “water distributer” in Greek) supporting multi-reservoir hydrosystem management. Its methodological framework has been based on the parameterization-simulation-optimization approach comprising stochastic simulation, network linear optimization for the representation of water and energy fluxes, and multicriteria global optimization, ensuring best-compromise decision-making. In its early stage, Hydronomeas was implemented in Object Pascal – Delphi. Currently, the software is being substantially redeveloped and its improved version incorporates new functionalities, several model novelties and interconnection with other programs, e.g., EPANET. Hydronomeas 2020 will be available at the end of 2020 as a free and open-source Python package. In this work we present the key methodological advances and improved features of the current version of the software, demonstrated in the modelling of the extensive and challenging raw water supply system of the city of Athens, Greece.
Baseflow separation methods in snowfed rivers in Mediterranean catchments: a process-oriented assessment for hydrograph analysis
Authors: Torralbo Pedro , Pimentel Rafael , Pérez-Palazón María José , Aparicio Javier , Herrero Javier , Aguilar Cristina , Polo María José
Published: March 2020

Water storage availability of semiarid regions is closely linked to the snow reservoir and its changes. The change of hydrological regime in mountain rivers is strongly affected by the snowpack’s dynamics, which plays a crucial role during spring and/or summer season in Mediterranean areas, becoming one of the major water sources to streamflow. This influence can be analyzed from different approaches; however, due to the concurrence of different processes, whose interaction and propagation undoubtedly affect runoff and baseflow generation, a process-oriented approach is required for further understanding the ultimate reasons behind the observed changes. Hence, the partitioning of river flow into baseflow, subsurface flown, and runoff, is a key step in hydrograph analysis and for better understanding snowfed rivers and how climate variability can influence their regime.

This work presents an assessment of different baseflow separation methods in mountain rivers of semiarid areas in the framework of a process-oriented approach for identifying the major sources/sinks of water. The study area comprises the headwaters of the different basins in the Sierra Nevada area, in southern Spain, within an altitudinal range of 1000-3479 m a.s.l., high slopes, and different facing. For this, a 20-yr series of daily flow in a gauged point in the Guadalfeo River that drains the southwestern area of Sierra Nevada is analyzed. Five standard baseflow separation methods, together with the simulation by the physically-based hydrological model WiMMed, which includes the module SNOWMED developed from an energy-water balance approach and validated in the study site, were selected and their results compared. Discussion on the effects of the final baseflow series on the descriptors of the direct-runoff hydrograph (daily time step) series is also included, considering snowmelt- and rainfall-driven events, and their combination.

The results not only provide a better understanding of baseflow separation in snowfed rivers in semiarid regions, but also assess hydrograph analysis in a process-oriented approach.  
Observing Sea Spray Aerosol Production in the Surf Zone of Hawaii
Authors: Ackerman Katherine , Taing Chung , Nugent Alison , Jensen Jorgen
Published: March 2020

Sea spray aerosol (SSA) play a significant role in the local climatology of coastal areas through direct radiative forcing and the indirect aerosol effect. Quantifying the size and concentrations of SSA is essential to understanding their influence in these coastal regions. Current observations of SSA in the surf zone come from coastline station measurements. These stations are often limited to observing only the mass of SSA produced and are unable to differentiate SSA concentrations of varying sizes. NCAR has developed an instrument known as a giant nucleus impactor (GNI) that allows deliquesced salt particles to impact onto polycarbonate slides exposed to a free airstream. These slides are then analyzed in a humidified environment under a microscope providing information about the SSA sizes and concentrations present. By modifying the NCAR GNI, we created a smaller, low-cost method known as a mini-GNI from 3D printing and Arduino microcontrollers. Using this new instrumentation, we attached the mini-GNI to a drone that sampled four locations over the ocean perpendicular to the coastline: the outer reef crest, inner reef crest, lagoon area, and shoreline. While sampling occurred, atmospheric and oceanographic measurements were recorded. This methodology provided us a baseline concentration or “open-ocean” concentration at the outer reef crest. It allowed us to compare how sizes and concentrations changed as the air parcel interacted with the surf zone. As the sampling locations moved closer to the shore, we’ve observed an increase in larger and more concentrated SSA that were contributed by the surf zone. We’ve also found that SSA concentrations have a stronger relationship to wave activity than to wind speed in our coastal environment. The ultimate goal is to quantify how the ocean environment and atmospheric conditions contribute to SSA production in the surf zone.
Snowmelt influence in shallow landslides
Authors: Rosso Renzo , Rulli Maria Cristina , Galizzi Mattia , Chiarelli Davide Danilo , Bocchiola Daniele
Published: March 2020

Mass wasting is a major landform shaping process in mountainous and steep terrains, and Italy is among the most affected countries in Europe. Lombardia region has 130.450 landslides mapped, covering an area of 3.300 km2 (i.e. 7.2% of the regional area). The 41% of landslides in Lombardia are rapid mass movements involving shallow soils, occurring mainly in the Alps and Fore-Alps. Many shallow landslides (SLs) result from infrequent meteorological events, inducing unstable conditions, or accelerate movements on otherwise stable slopes. In mountainous areas such as the Alps of Lombardia region, snowmelt concurs with rainfall intensity, and duration in setting the hydrologic conditions favorable to the occurrence of SLs. However, snowmelt contribution to SLs triggering is little investigated hitherto.  In regions experiencing seasonal snowmelt in spring and summer, melting water thereby could decrease the intensity and duration of rainfall needed for SL initiation, or even lead to LSs in dry weather conditions.  

Under the umbrella of the project MHYCONOS, a project founded by Fondazione CARIPLO, we developed a robust, and parameter wise parsimonious model, that mimics the triggering mechanism of shallow landslides by accounting for the combined effect of precipitation duration and intensity in, and snowmelt at thaw. The model is applied to the case study of Tartano basin, paradigmatic of SLs in the Alps of Lombardia, where in July 1987 a SL event produced 30 fatalities.

Our results show that about 37% of the Tartano Basin slopes display unstable condition, and more than 50% therein is influenced by soil moisture variation. Using a traditional (i.e. rainfall based) approach, occurrence of shallow landslides is predicted only during rainy periods, mainly October and November. In contrast, when including snow melt, the model mimics failures potentially also during April and May, when melting rate is the highest, and may increase triggering potential of rainfall. Currently, our efforts are aimed to conduct interviews and construct temporally based datasets, where occurrences of snow melt driven failures can be evidenced.

Risk perception by population may change, and public authority may be prepared to implement emergency plans in order to prevent injuries, causalities and damages to infrastructures also during spring time, when shallow landslides may occur in response to fast snow melt, even during clear sky days, in lack of precipitation.

 