bluuebunny/crossref_metadata_2025 huggingface dataset:
Magma transport in the shallow crust – the dykes of the Chachahuén volcanic complex (Argentina)
Authors: Schmiedel Tobias , Burchardt Steffi , Guldstrand Frank , Mattsson Tobias , Galland Olivier , Palma Octavio , Rhodes Emma , Witcher Taylor , Almqvist Bjarne
Published: March 2020

Recent eruptions such as the Kilauea 2018 (fissure) eruption on Hawaii are the result of magma intruding into Earth’s crust and ascending towards the surface. Magma is dominantly transported, through the shallow crust in form of vertical sheet intrusions (dykes). Even though dyke propagation and emplacement has been monitored with geodetic and geophysical methods, direct observations of subsurface intrusion processes remain inaccessible due to the hazardous nature of active volcanic and igneous systems. Therefore, we studied the extinct and eroded volcanic system of the Chachahuén volcanic complex (CVC) in Argentina to investigate the scale and physical mechanisms of magma transport in volcanic and igneous plumbing systems.

The Chachahuén volcanic complex is located in the northern part of the Neuquén Basin, east of the southern volcanic zone (SVZ) of the Andes. A decline in volcanic activity during the Quaternary and erosion have exposed the shallow part of the Miocene CVC’s plumbing system, including two major vertical sheet intrusions: (1) the Great Dyke and (2) the Sosa Dyke.

The objective of this ongoing study is to characterize the mechanisms of magma transport within the two exposed dykes to better understand the physical processes during their emplacement. We apply a multiscale approach combining field work and state-of-the-art analytical techniques, i.e., drone/ground-based photogrammetry, Fourier Transform Infrared Spectroscopy (FTIR), Electron Backscatter Diffraction (EBSD) and Anisotropy of Magnetic Susceptibility (AMS), with traditional geological methods, i.e., microstructural analysis and igneous petrology. Thus, we can investigate the effect of magma rheology (small-scale) on the outer shape and morphology of the dykes (large-scale).

Our results using high-resolution 3D outcrop models show a segmentation of the investigated dykes. Each of these dyke segments shows blunt ends. This suggests either the emplacement of a highly viscous magma or a weak brittle host rock. Flow features identified with AMS analysis indicate a dominantly lateral magma transport within the dykes. To estimate the magma viscosity during emplacement FTIR (H2O content of the initial melt), and microstructural analysis (for crystallinity) are performed at the moment. These analyses in combination with a map of the host rock and, the dyke morphologies, will help to characterize the dominantly controlling mechanism(s) of magma emplacements in the CVC. Finally, the new findings from this project will contribute to the general understanding on how the physical properties of the magma affect the shape of magma bodies and magma flow in the Earth’s shallow crust.
Role of stationary convective bands and antecedent conditions on the flood response to the Vaia storm (October 27-30, 2018) in the Eastern Italian Alps
Authors: Zaramella Mattia , Marchi Lorenzo , Marra Francesco , Comiti Francesco , Crema Stefano , Marchio Mattia , Borga Marco
Published: March 2020

Between the morning of 27 October 2018 and the evening of 29 October 2018, heavy precipitation over the Eastern Italian Alps led to damaging flooding. The event, which occurred at the end of a climatic anomaly of prolonged drought, developed into two phases, with a first phase (October 27-28) dominated by more stratiform orographically-enhanced precipitation. After a short lull, a second and more intense phase of the event took place on the 29th, when a cold front from the Gulf of Lion entered the Mediterranean basin triggering explosive cyclogenesis. A characteristic of the second phase of the storm is the rainfall organization in well-defined convective bands, some of which persisted at the same location for up to 3 hours. The bands, aligned from southeast to northwest, were initially located downstream of the pre-alpine region.

The work aims to investigate the impact of the stationary convective bands and of the dry antecedent conditions on the flood response to the storm. The availability of high-resolution rainfall estimates from weather radar and of dense rain gauge network data, along with flood response observations from stream gauge data and post-event surveys, enables to study the hydrometeorological and hydrological mechanisms associated with this extreme storm and the consequent flood response.

Observational and model analyses of the hydrologic runoff in two areas heavily impacted by the storm (Noce river basin, in the Trentino Province, and upper Cordevole river basin, in the Veneto Region) illustrate how the structure and evolution of the stationary convective bands translate into scale dependent flood response. For the upper Cordevole river basin, the event envelope curve shows two peculiar behaviors: (a) basin scale ranging from 1 to 200 km2, with peak unit discharges decreasing from 10 to 4 m3s-1km-2; (b) basin scale ranging from 200 to 2000 km2, with smaller peak unit discharges. The spatial extent of the first region is controlled by the structure of the central convective band. Moreover, the spatial moments of catchment rainfall are exploited to identify the impact of the convective cells motion along the stationary band on the flood response.
Pyrocko - A Versatile Software Framework for Seismology
Authors: Heimann Sebastian , Kriegerowski Marius , Isken Marius , Vasyura-Bathke Hannes , Cesca Simone , Nooshiri Nima , Petersen Gesa , Metz Malte , Steinberg Andreas , Sudhaus Henriette , Dahm Torsten
Published: March 2020

Pyrocko is an open source seismology toolbox and library, written in the Python programming language. It can be utilized flexibly for a variety of geophysical tasks, like seismological data processing and analysis, modelling of waveforms, InSAR or GPS displacement data, or for seismic source characterization. At its core, Pyrocko is a  library  and  framework  providing  building  blocks  for researchers  and  students  wishing  to  develop  their  own applications. Pyrocko contains a few standalone applications for everyday seismological practice. These include the Snuffler program, an extensible seismogram browser and workbench, the Cake tool, providing travel-time and ray-path computations for 1D layered earthmodels, Fomosto, a tool to manage pre-calculated Green’s function stores, Jackseis, a command-line tool for common waveform archive data manipulations, Colosseo, a tool to create synthetic earthquake scenarios, serving waveforms and static displacements, and new, Sparrow, a 3D geophysical data visualization tool. This poster gives a glimpse of Pyrocko’s features, for more examples and tutorials visit https://pyrocko.org/.
Rotational sensor on a volcano: New insights from Etna, Italy
Authors: Eibl Eva P. S. , Currenti Gilda , Wassermann Joachim , Jousset Philippe , Vollmer Daniel , Larocca Graziano , Pellegrino Daniele , Pulviventi Mario , Contrafatto Danilo , Yuan Shihao
Published: March 2020

Rotational seismology is an emerging field of seismology with rotational sensors such as blueSeis-3A as portable devices. We deployed one of these rotational sensors on Etna volcano from August to September 2019 in the middle of a 26 stations broadband seismic array and a fibre-optic cable deployed for Distributed Acoustic Sensing (DAS). We, therefore, recorded continuously the full seismic wavefield using a 6C station (rotational sensor co-located with a broadband seismometer) for 30 days.

We will present an overview of our work on the rotational data in combination with a broadband seismometer. We will (i) compare the translational with rotational data and show how they complement each other, (ii) calculate back azimuths using only a 6C station or using merely the horizontal components of the rotational sensor, (iii) determine Love and Rayleigh wave velocities from the rotation rate and (iv) perform a simple inversion for the shallow velocity structure below the station, and finally (v) discuss the usefulness of such a sensor in a volcanic environment and (vi) highlight what new it would bring to volcano-related research.
A culture of proactive drought management? Unraveling the perception and management of droughts in Swedish municipalities.
Authors: Teutschbein Claudia , Albrecht Frederike , Grabs Thomas , Blicharska Malgorzata
Published: March 2020

Hydro-climatic risks like droughts are a natural part of climate: they always have and always will take place. They are generally controlled by natural climate variability and anthropogenic impacts, but their proportional roles are not yet fully understood nor quantiﬁed. The most recent Swedish drought events of 2016/2017 and 2018 clearly showed that even a nation in Northern Europe not commonly associated with droughts could be fretting over water shortages. Both events had severe effects on the environment and Swedish society, ranging from forest ﬁres to lost harvests and emergency slaughter of livestock and lower revenues from tourism. Another major societal function affected by these drought events was the drinking water supply. As Sweden is a country usually abundant with water, we argue that these two consecutive droughts hit Sweden in a state of unpreparedness. We posit that Swedish society is currently limited in its ability to independently deal with droughts and their consequences for different functions of the society. In line with the 6th Sustainable Development Goal (‘Ensure availability and sustainable management of water and sanitation for all’), such drought conditions are to be better managed in the future, which urgently requires a more comprehensive understanding of the interactions between physical and socio-economic systems during drought events. Municipalities are the most important decision makers within crisis preparedness and management. Hence, it is important to investigate how their perceptions and strategies are shaped. We hypothesize that different actors in the society could have coped better with the recent water shortages if they better understood the risks faced and if they had right strategies and instruments to prepare for extreme droughts. Therefore, we conducted a survey among local decision makers in Sweden to analyse drought perception, crisis preparedness and management among more than 100 municipalities. We directly compared decision makers’ perception of recent droughts to the observed drought severity as measured by different drought indices. As the assumption that access to good water guarantees a continued welfare and functioning of our society is the foundation of Swedish water governance, we argue that Sweden needs to focus on increasing society’s adaptive capacity and resilience in order to guarantee a robust drinking water supply.
Ridge estimation iterative algorithm to ill-posed uncertainty adjustment model
Authors: lu tieding
Published: March 2020

 Uncertainties usually exist in the process of acquisition of measurement data, which affect the results of the parameter estimation. The solution of the uncertainty adjustment model can effectively improve the validity and reliability of parameter estimation. When the coefficient matrix of the observation equation has a singular value close to zero, i.e., the coefficient matrix is ill-posed, the ridge estimation can effectively suppress the influence of the ill-posed problem of the observation equation on the parameter estimation. When the uncertainty adjustment model is ill-posed, it is more seriously affected by the error of the coefficient matrix and observation vector. In this paper, the ridge estimation method is applied to ill-posed uncertainty adjustment model, deriving an iterative algorithm to improve the stability and reliability of the results. The derived algorithm is verified by two examples, and the results show that the new method is effective and feasible.
The new Swiss Glacier Inventory SGI2020: From a topographic to a glaciological dataset
Authors: Linsbauer Andreas , Hodel Elias , Huss Matthias , Bauder Andreas , Fischer Mauro , Weidmann Yvo , Bärtschi Hans
Published: March 2020

A glacier inventory describes the extent of all glaciers at a given point in time and in periods of rapid glacier change a frequent update is needed. The Swiss Glacier Inventory 2010 (SGI2010) is the last official inventory for Switzerland and was derived by manual digitization from high-resolution (25 cm) aerial orthophotographs from swisstopo (Federal Office of Topography). To regularly produce a revised inventory, based on the high-quality aerial images from swisstopo acquired at a three-year interval, the workload cannot be covered by GLAMOS (Glacier Monitoring Switzerland, www.glamos.ch) on its own. As part of the development of the new topographic landscape model of Switzerland (swissTLM3D), swisstopo introduced – based on requirements defined by GLAMOS – the object class “glaciers”. This secures that Swiss glaciers are recurrently mapped based on high-resolution data on a long term. Swiss Glacier Inventories can therefore be derived by GLAMOS from the TLM object class “glaciers”.

The SGI2020 is the first glacier inventory produced by GLAMOS based on the new workflow and stands out with an unprecedented level of detail regarding glacier mapping. As the glacier-excerpt from the swisstopo TLM is a landcover dataset, produced according to guidelines for topographical purpose, it does not fit all glaciological requirements. Here, we present the necessary steps and adjustments to derive a new glacier inventory for the period 2013-2018 that fits all glaciological criteria. Furthermore, we compare the resulting dataset with former SGI’s and pin down the major changes and differences emerging from different methodologies used. We particularly emphasize on problematic definitions of glacier boundaries related to snow coverage and/or supraglacial debris and provide updated results for glacier area changes in the Swiss Alps over the last decades.
Integrate risk from climate change in China under global warming of 1.5°C and 2.0°C
Authors: Liu Lulu , Wu Shaohong , Gao Jiangbo
Published: March 2020

Risk of climate-related impacts results from the interaction of climate-related hazards (including hazardous events and trends) with the vulnerability and exposure of human and natural systems. Despite the commitment of the Paris Agreement, the integrate research on climate change risk combining risk‐causing factors and risk‐bearing bodies, the regional differences in climate impacts are still missing. In this paper we provide a quantitative assessment of hazards and socioeconomic risks of extreme events, risks of risk‐bearing bodies in China under global warming of 1.5 and 2.0°C based on future climate scenarios, and quantitative evaluation theory for climate change risk. For severe heat waves, hazards might significantly intensify. Affected population under 2.0°C warming might increase by more than 60% compared to that of 1.5°C. Hazards of severe droughts and floods might strengthen under Representative Concentration Pathway 8.5 scenario. Economic losses might double between warming levels of 1.5 and 2.0°C, and the population affected by severe floods might continuously increase. Under the integrate effects of multiple disasters, the regions with high population and economic risks would be concentrated in eastern China. The scope would gradually expand to the west with socioeconomic development and intensification of extreme events. High ecological risks might be concentrated in the southern regions of the Yangtze River Basin, while the ecological risk in northern China would expand. High agriculture yield risks might be distributed mainly in south of the North China Plain, the Sichuan Basin, south of the Yangtze River, and west of Northwest China, and the risk levels might continuously increase.
Hydrogeological controls on groundwater recharge in a weathered crystalline aquifer: A case study from the Makutapora groundwater basin, Tanzania
Authors: Zarate Emanuel , MacDonald Alan , Swift Russell , Chambers Jonathan , Kashaigili Japhet , Mutayoba Edmund , Taylor Richard , Cuthbert Mark
Published: March 2020

Drylands (semi-arid/arid regions) represent >35% of the Earth’s surface, support a population of around 2 billion people, and are forecast to be increasingly water stressed in coming decades. Groundwater is the most reliable source of water in drylands, and it is likely that the structure and hydraulic properties of superficial geology play a crucial role in controlling groundwater recharge in these regions.  However, the spatio-temporal hydrogeological controls on the rates of groundwater recharge, and their sensitivity to environmental change are poorly resolved.

In the Makutapora groundwater basin (Tanzania), an analogue for semi-arid tropical areas underlain by weathered and fractured crystalline rock aquifers, we conducted a series of geophysical surveys using Electrical Resistivity Tomography (ERT) and frequency domain electromagnetic methods (FDEM). Using these data, in conjunction with borehole logs, we identify and delineate five major lithological units in the basin: 1) Superficial deposits of coarse sand (>200 Ω m) 2) Highly conductive smectitic clays (1-10 Ω m) 3) Decomposed pedolitic soils (30-100 Ω m) 4) Weathered saprolite (100-700 Ω m) and 5) Fractured granitic basement (>700 Ω m). We also identify 10-50m wide zones of normal faulting extending across the basin and cutting through these units, interpreted with the aid of analysis of a digital elevation model alongside the geophysics data.

These results are combined with existing long-term hydrological and hydrogeological records to build conceptual models of the processes governing recharge. We hypothesise that: 1) Zones of active faulting provide permeable pathways enabling greater recharge to occur; 2) Superficial sand deposits may act as collectors and stores that slowly feed recharge into these fault zones; 3) Windows within layers of smectitic clay underlying ephemeral streams may provide pathways for focused recharge via transmission losses; and 4) Overbank flooding during high-intensity precipitation events that inundate a greater area of the basin increases the probability of activating such permeable pathways.

Our results suggest that configurations of superficial geology may play a crucial role in controlling patterns, rates and timing of groundwater recharge in dryland settings. They also provide a physical basis to improve numerical models of groundwater recharge in drylands, and a conceptual framework to evaluate strategies (e.g. Managed Aquifer Recharge) to artificially enhance the availability of groundwater resources in these regions.
'Transport and Transport-Infrastructure' - key findings of a "User Needs" survey
Authors: Matulla Christoph , Enigl Katharina , Macnab Audrey , Evans Philip , Roser Gavin , Muchemi Samuel , Fleming Gerald , Dabberdt Walt , Grimes Sarah , Leviäkangas Pekka
Published: March 2020

The aim of this contribution is to present the design as well as findings of a survey targeted assessing the needs of stakeholders in the transportation domain with respect to climate change driven damages. This ‘User needs survey’ is one of the major objectives of multifarious collaborations investigating anticipatory asset protection strategies under accelerated climate change. The viability of these efforts is guaranteed by pairing up the scientific community (CIT, University of Vienna, BOKU, TU Vienna) with notable stakeholders (F&L, WMO, BMNT).

The ‘User needs’ survey, was carried out in cooperation between the Climate Impact Team (CIT) the European Transport, Freight and Logistics Leaders Forum (F&L) and the World Meteorological Organization (WMO). The aim of the survey is to identify services that stakeholders in the realm of transportation themselves consider significant and beneficial. 

Therefore, findings should be of vital importance for -- (i) setting up meaningful climate services; (ii) selecting sustainable protection measures strengthening transportation system resilience in the face of future climate change; (iii) compiling the chapter on 'Land Transport' in WMO’s new Service Delivery Guide -- as they ensure the expediency of the services described.

Presented results encompass: (i) an assessment of extreme events in terms of their damaging impacts on transport, freight and logistics by stakeholders; (ii) an assessment of the vulnerability of assets in transport, freight and logistics by stakeholders; (iii) an illustration of the extent of impacts climate-change (through shifts in extremes and associated threats) has had on transport, freight and logistics over the past decades; (iv) the stakeholders' expectations regarding future developments towards advancing climate-change and (v) an evaluation of time horizons (short, medium and long term) at which stakeholders need services. 

A summary completes this contribution.
Experimental study on the thermo- and hydro- properties of two bentonites as buffer materials
Authors: Huang Wei-Hsing
Published: March 2020

This study aims at investigating the hydraulic and thermal properties which are important for buffer materials to be used for geological disposal of high-level radioactive wastes. MX-80 bentonite and Kunigel V1 bentonite, originated from Wyoming USA and Japan, respectively, were used in the experimental program. The characteristics of these 2 bentonites, including soil-water characteristic curve, swelling pressure, hydraulic conductivity, and thermal conductivity were determined in the laboratory. And these data are applied in the simulation of the resaturation processes of buffer material in a deposition hole, such that a comparison can be made on the thermo-hydro-mechanical coupling effects of the buffer material can be evaluated. It is found that the two bentonites do not behave very differently in terms of the moisture distribution and heat transfer characteristics with the same boundary conditions assumed. 
Study of the Earth rheological properties from polar motion
Authors: Bizouard Christian , Nurul Huda Ibnu , Lambert Sébastien
Published: March 2020

Since the beginning of the 20th century, the observation of the Earth rotation variations through astro-geodetic
techniques enables to investigate the global rheological properties of the Earth, in particular, the resonance
parameters of the free rotation modes reflect the solid Earth anelasticity, the ocean response to an external
forcing, and the properties of the fluid inner core, eventually of the solid inner core. Better constraints on
these resonance parameters can be obtained by confronting the observed terrestrial motion of the rotation pole
(the so-called polar motion) - including nutation as a retrograde diurnal polar motion - to the modeled excitation
producing it. The more precise the modeled excitation and the observed polar motion are, the better the
Earth rheological properties will be determined. For now, the best precision is reached in the
nutation band. So, the analysis has been first dedicated to a direct adjustment of the nutation components
from VLBI delays, then the adjustment of the resonance parameters in the transfer function between the observed
nutation terms and the corresponding rigid nutation terms that reflects the luni-solar forcing. The obtained
resonance parameters confirms in particular the shortening of the polar motion resonance period of about 40 - 50 day
in the retrograde diurnal band. Then, we show that the dynamical behavior of the oceans in the diurnal band is
mostly responsible for that. We also predicted a supplementary change of the resonance parameters in the vicinity
of the free core nutation resonance, as expected from the solid Earth response, and confirmed by the adjustment of
these parameters through the nutation terms. In addition to the nutation band, we revisit the estimation of the
polar motion resonance parameters in the seasonal band, dominated by the Chandler wobble, in light of the most
recent global circulation models of the hydro-atmospheric layers. Finally, we extend the investigation of polar motion resonance to the
prograde diurnal polar motion, where the excitations mostly result from the ocean tides. We obtain a resonance
period of about 393 days, and confirmed by our prediction based on the ocean tidal models. These results allow us to
impose constraints on the frequency dependence of the Love number k2 and the Love number oceanic ko, characterizing
respectively the response of the solid Earth and the oceans to an external potential of degree 2. 
The interplay of glacial/interglacial climate-CO2 and productivity effects on coccolith calcification and vital effects across the MIS 12 to MIS 9 in the western tropical Atlantic
Authors: González-Lanchas Alba , Stoll Heather M. , Flores José-Abel , Sierro Francisco J. , Hernandez-Almeida Ivan , Guitian Jose
Published: March 2020

Coccolithophores play an important dual role in ocean biogeochemistry: they use dissolved inorganic carbon (DIC) in the surface for both photosynthesis and coccolith calcification. Stable isotopes in coccoliths are the result of various effects, including different vital effects, allowing hypotheses about the varying active carbon acquisition strategies in response to changing environmental conditions. Understanding the physiological mechanisms that cause these changes remains challenging.

The MIS 12 to MIS 9 interval is a crucial climatic period encompassing changing glacial-interglacial cyclicity and pronounced variations in atmospheric CO2 concentration. Different paleorecords indicate that coccoliths were an important component of the carbonate fraction during this interval, with the outstanding worldwide dominance of the highly calcified coccolithophore species Gephyrocapsa caribbeanica.

The carbon isotopic fractionation during photosynthesis (εp) in alkenones, biomarkers produced by coccolithophores, is a proxy to reconstruct past aqueous CO2 concentration. Here we present a new εp reconstruction spanning this glacial/interglacial interval (460 to 330 kyr) at ODP Site 925 in the western tropical Atlantic. We aim to evaluate the interplay of CO2 and productivity effects on coccolith calcification and stable isotopes (δ18O and δ13C) in coccolith calcite integrating these data with the size and thickness of coccolith platelets and the geochemical Sr/Ca record.

The comparison of mean coccolith size with coeval samples from the deeper ODP Site 929 allows the evaluation of the degree of nannofossil dissolution across the interval.
Can we get more out of rainfall thresholds? The temporal resolution tradeoff and the role of antecedent wetness and rainfall spatial variability
Authors: Leonarduzzi Elena , Molnar Peter
Published: March 2020

Rainfall event properties like maximum intensity, total rainfall depth, or their representation in the form of intensity-duration (ID) or total rainfall-duration (ED) curves, are commonly used to determine the triggering rainfall (event) conditions required for landslide initiation. This rainfall data-driven prediction of landsliding can be extended by the inclusion of antecedent wetness conditions. Although useful for first order assessment of landslide triggering conditions in warning systems, this approach relies heavily on data quality and temporal resolution, which may affect the overall predictive model performance as well as its reliability.

In this work, we address three key aspects of rainfall thresholds when applied at large spatial scales: (a) the tradeoffs between higher and lower temporal resolution (hourly or daily) (b) the spatial variability associated with long term rainfall, and (c) the added value of antecedent rainfall as predictor. We explore all of these by utilizing a long-term landslide inventory, containing more than 2500 records in Switzerland and 3 gridded rainfall records: a long daily rainfall dataset and two derived hourly products, disaggregated using stations or radar hourly measurements.

We observe that while predictive performances improve slightly when utilizing high quality hourly record (using radar information), the length of the record decreases, as well as the number of landslides in the inventory, which affects the reliability of the thresholds. A tradeoff has to be found between using long records of less accurate daily rainfall data and landslide timing, and shorter records with highly accurate hourly rainfall data and landslide timing. Even daily rainfall data may give reasonable predictive performance if thresholds are estimated with a long landslide inventory. Good quality hourly rainfall data significantly improve performance, but historical records tend to be shorter or less accurate (e.g. fewer stations available) and landslides with known timing are fewer. Considering antecedent rainfall, we observe that it is generally higher prior to landslide-triggering events and this can partially explain the false alarms and misses of an intensity-duration threshold. Nevertheless, in our study antecedent rainfall shows less predictive power by itself than the rainfall event characteristics. Finally, we show that we can improve the performances of the rainfall thresholds by accounting for local climatology in which we define new thresholds by normalizing the event characteristics with a chosen quantile of the local rainfall distribution or using the mean annual precipitation.
Flood variability in northern Spain during the last millennium recorded in lacustrine sedimentary archives
Authors: Corella Juan Pablo , Wilhelm Bruno , Benito Gerardo , Favre Anne-Catherine , Valero-Garcés Blas L.
Published: March 2020

Floods are among the most destructive natural disasters, and robust knowledge about their past, present and future trends is therefore crucial for the sustainable development of societies worldwide. Paleoflood deposits in lacustrine sedimentary sequences enable the continuous reconstruction of flood variability at centennial to millennial scale beyond instrumental hydrological datasets. FLOODARC MSCA project (2019-2021) aims to provide a more comprehensive understanding of the long-term flood variability in the Iberian Peninsula by investigating flood archives in several Spanish lake records. Preliminary results show a see-saw pattern in flood frequency variability during the Medieval Climate Anomaly and the Little Ice Age transition with more (less) flood events occurring during cold (warm) phases in Atlantic and Mediterranean areas respectively. These dissimilarities seem to be controlled by the hydroclimate variability at the regional scale as well as by historical land use changes in different areas of northern Spain.
Ecosystem service-based approach for evaluating the effectiveness of nature-based solution in mitigating climate change and land degradation issues in a city region
Authors: Sannigrahi Srikanta , Basu Bidroha , Sarkar Basu Arunima , Pilla Francesco
Published: March 2020

Nature-based solutions (NBS) are the bundle of natural and ecological functions that are proven to be beneficial to address varied socio-ecological challenges at cities. The conceptual adaptation of NBS alternatives in managing leading issues such as climate change and its impact on community well-being, sustainable uses of natural resources, encouragement for using soft engineering approaches for nourishing synergic benefits of natural capitals, empowering population health and reducing disaster risk are increasing substantially over the past few decades. The other term Ecosystem Services (ESs) refers to the variety of supports and benefits that humans obtained from the natural environment, which add human well-fare and improve the overall socio-ecological status at cities. NBS alternatives include increase in green areas by urban forestry and plantation, preserving urban inland water bodies and wetlands, introducing sustainable, cost-efficient, and environment-friendly urban drainage and sewage systems, reducing the impervious surface cover by increasing green cover, etc. However, substantial evidence is required to understand the importance of NBS alternatives and its implication in producing various regulatory, provisioning, supporting, and cultural urban ecosystem services that collectively produce ranges of economic, social, and environmental supports and benefits. This study performs a thorough quantitative and qualitative assessment to explore the possibilities of adopting varied NBS alternatives to reduce environmental problems in a city and to quantify the economic values of different NBS alternatives using spatially explicit biophysical and economic valuation approaches. Two spatially explicit integrated models Integrated Valuation of Ecosystem Services and Trade-off (InVEST) and Soil Water Assessment Tool (SWAT) was used to quantify the biophysical and economic values of different NBS alternatives and ESs in Dublin, Ireland. The outcome of the study could be a reference to the concerned stakeholders, decision-makers, urban planners, and land administrators for adopting suitable NBS alternatives in managing the uprising environmental and socioecological issues in a city region.
Imaging of Ganymede through Energetic Neutral Atoms sputtered/backscattered from the surface
Authors: Pontoni Angèle , Shimoyama Manabu , Fatemi Shahab , Poppe Andrew , Futaana Yoshifumi , Barabash Stas
Published: March 2020

Brightness asymmetries on the surface of Ganymede are thought to be caused by ion impact from Jovian co-rotating plasma. The Jovian Neutrals Analyzer instrument onboard the JUICE spacecraft will help investigate this theory by yielding a map of ion precipitation at the surface of Ganymede through the observation of low-energy Energetic Neutral Atoms (ENAs) (10 eV to 3300 eV) sputtered or backscattered by the Jovian plasma.

In order to optimize JNA operations planning at Ganymede, we estimate the expected energy distribution of ENAs caused by the impacting Jovian plasma. As an input, we use results from a three dimensional hybrid plasma simulation, which gives us the energy distribution of precipitating H+, O++ and S+++ at the surface of Ganymede. We then calculate the ENA yield using respectively Famà’s model (Famà, 2008) for the sputtering yield of water ice and Thompson-Sigmund’s model (Sigmund, 1969) for electronic sputtering to get the energy distribution of the ENAs.
Statistical postprocessing of heavy precipitation
Authors: Hess Reinhold , Schaumann Peter , Schmidt Volker
Published: March 2020

Heavy precipitation rates of more than 15 mm per hour are captured only about once a year at each rain gauge within Germany. More extreme events are even less frequent. Point by point verifications show that forecasts of heavy precipitation of the ensemble system COSMO-D2-EPS of DWD can be improved by statistical postprocessing. This is done in a MOS approach using long time series of synoptic observations and numerical forecasts that are required in or­der to gather a significant number of heavy precipitation events for reliable statistical model­ling.

Highest precipitation rates of convective events usually realise more likely in the surrounding of rain gauges rather than exactly above their small funnels. Statistical forecasts modelling these point observations usually underestimate maximal rain rates and result in low probabili­ties for the occurrence of heavy precipitation at a given location.

Point processes of stochastic geometry can be used to model area probabilities that provide the probability that precipitation occurs anywhere (at least at one point) within that area. Verifications with gauge adjusted radar data reveal that point probabilities are representative for very small areas, but area probabilities are significantly larger already for areas of 20*20 km2.

The use of radar data as area observation system allows to statistically generate calibrated precipitation forecasts for arbitrary areas. However, the question remains, which size of area is most relevant for the public and most suitable for weather warnings.
Can increasing greenhouse gases cause tipping of the AMOC?
Authors: Wood Richard
Published: March 2020

Climate models consistently project a weakening of the Atlantic Meridional Overturning Circulation (AMOC) in response to increasing greenhouse gases (GHGs) over the 21st Century. Models also show the potential for multiple equilibria and tipping points of the AMOC, in response to fresh water forcing. However longer term model integrations at increased levels of GHGs suggest that AMOC weakening is transient, with the AMOC recovering to its initial strength after GHGs are stabilised. Hence the ‘traditional’ forcing scenarios of increasing GHGs followed by stabilisation do not appear to induce tipping. But with increased interest in ‘overshoot’ scenarios motivated by the Paris climate agreement, is it possible that there are climate mitigation pathways that do carry a risk of AMOC tipping?

In this study we present a simple AMOC model which captures both the thermal and fresh water forcing associated with GHG increase, and is able to reproduce previous GCM results for both GHG and idealised fresh water (‘hosing’) scenarios. We identify the conditions under which AMOC tipping could occur, and their significance for ‘safe’ climate mitigation pathways.
Quantifying deposition pathways of Ozone at a rainforest site (ATTO) in the central Amazon basin
Authors: Sörgel Matthias , Tsokankunku Anywhere , Wolff Stefan , Araùjo Alessandro , Assis Pedro , Harder Hartwig , Martins Giordane , Sá Marta , Souza Rodrigo , Williams Jonathan , Zannoni Nora
Published: March 2020

Direct eddy covariance flux measurements of O3 in tropical forests are sparse and deposition velocities of O3 for tropical forest have large uncertainties in models. Therefore, we measured O3 fluxes at different heights ( 4 m, 12 m, 46 m and 81 m), which is 2 levels within canopy (below crown layer) and two levels above. At the same levels heat and CO2 fluxes were measured by eddy covariance to differentiate upper canopy fluxes from understory and soil fluxes and to infer stomatal conductance based on the inverted Penman-Monteith equation. Further measurements include the profiles of O3, NOx, CO2 and H2O which are used to calculate storage fluxes and reactions of O3 with NOx within the air volume. Additionally, leaf surface temperature and leaf wetness were measured in the upper canopy (26 m) to infer their influence on the non-stomatal deposition. The measurements took place at the ATTO (Amazon Tall Tower Observatory) site that is located about 150 km northeast of the city of Manaus in the Amazon rainforest. (02°08’38.8’’S, 58°59’59.5’’W). The climate in this region is characterized by a rainy (350 mm around March) and a dry season (ca. 80 mm in September). During the wet months, the air quality is close to pristine, while strong pollution from biomass burning is evident in the dry season. Therefore, we will present results from two intensive campaigns (3- 4 flux levels) for the rainy season (March to May) and the dry season (September to December) 2018.

 

The focus of the analysis is the partitioning between a) the crown layer and understory and b) stomatal and non-stomatal deposition with a further analysis of the non-stomatal pathways. Non-stomatal deposition is analyzed by quantifying gas-phase reactions of O3 with NOx and an estimate of O3 reactivity by VOCs. Furthermore, the remaining (surface) deposition is analyzed according to its relations with leaf surface temperature and leaf wetness.
Relating thermohaline simulation of salt dissolution to land collapse at a Transylvanian salt diapir, Romania
Authors: Zechner Eric , Dresmann Horst , Mocuţa Marius , Danchiv Alex , Huggenberger Peter , Scheidler Stefan , Wiesmeier Stefan , Popa Iulian , Zlibut Alexandru
Published: March 2020

The presented study estimates salt dissolution caused by groundwater around a salt diapir in the Transylvanian Basin, which is facing land-collapse hazards related to historic salt mining activities. Because the amount of salt dissolution is controlled by the concentration gradients and fluxes near vulnerable areas of the salt dome, specific attention has been given to hydrogeological boundary conditions. They include the hydraulic role of possible more permeable fault zones along the salt dome, and the potential access to the salt diapir of over-pressurized subsaturated groundwater within regional scale sandstone layers. A structural three-dimensional (3D) model of the salt diapir, the adjacent basin sediments, and the mining galleries was developed based on existing maps, borehole data, own field observations, and geological publications of the Transylvanian Basin. The salt dissolution potential was simulated with 2D vertical thermohaline flow and transport model scenarios along the southeastern flank of the diapir. Results showed that the following factors increase the salt dissolution capacity along the upper 180 m of the diapir: (1) the presence of more permeable Quaternary alluvial sediments in connection with a fault zone of higher permeability along the diapir, and (2) the presence of more permeable sandstone units within the Miocene sediments in the east of the diapir, which provide freshwater access to the upper parts of the diapir. Thermohaline simulation with viscosity variation of the fluid, instead of a constant viscosity, influences the resulting salt fluxes by up to 50% within studied temperature ranges of 10 to 60°C in the model domain. The range of theoretical dissolution rates along the upper 180 m of the diapir supports the hypothesis that cavern collapse is more likely to occur where cavern side walls have already been mined to almost no remaining side walls of rock salt, which is the case in the southeastern part of the diapir. A past land collapse from 2010, which formed a 70-90 m wide saline lake, has occurred in this area southeast of the diapir appearing to be the more vulnerable to land collapse.

Zechner, E., Dresmann, H., Mocuţa, M., Danchiv, A., Huggenberger, P., Scheidler, S., Wiesmeier, S., Popa, I., Zlibut, A. (2019): Salt dissolution potential estimated from two-dimensional vertical thermohaline flow and transport modeling along a Transylvanian salt diapir, Romania, Hydrogeol. J., 27, 1245-1256, https://doi.org/10.1007/s10040-018-1912-1.
Modelling the base of fluvial Quaternary sediments in the “Seewinkel” area (Austria)
Authors: Zemann Paul , Draganits Erich , Hodits Barbara , Schiel Bernhard , Berka Rudolf , Weissl Michael
Published: March 2020

The “Seewinkel” region is the eastern most part of Austria located east of Lake Neusiedl, Austria’s largest lake. The area is located in the western part of the Little Hungarian Plain and is characterized by extremely low relief and abundant shallow lakes and pans. The general geological setting shows Quaternary fluvial sediments with minor aeolian cover in places, above Pannonian (Miocene, Tortonian) limnic fine-grained sediments. Recent seismic data show the existence of abundant brittle faults in the subsurface, related to the formation of the Pannonian Basin.

We model the thickness of the Quaternary sediments in this hardly exposed area, to gain insight into their deposition, the influence of pre- and post-tectonic structures and to improve our understanding of the uppermost groundwater storey. This study combines existing borehole data (mainly from OMV, Geological Survey of Austria, Gruppe Wasser Ziviltechnikergesellschaft für Wasserwirtschaft GmbH and Amt der Burgenländischen Landesregierung) and observations from construction sites with high-resolution airborne laser scanning (ALS) topographic data to model the thickness of the Quaternary sediments in an Open-Source geographic information systems (GIS) environment.

The Quaternary fluvial sediments pinch out towards northwest, being virtually zero close to the eastern shore of Lake Neusiedl, and increase in thickness towards east, reaching almost 30 m at the Austrian/Hungarian border. This tendency is mimicking the thickness trend of the underlying Pannonian sediments and most probably is related to the still ongoing regional subsidence in the Little Hungarian Plain.
Are the antecedent drought conditions magnifying the summer hot extremes in Australia
Authors: Páscoa Patrícia , Gouveia Célia , Russo Ana , Ribeiro Andreia
Published: March 2020

The occurrence of extreme climate events such as droughts and heatwaves can have negative economic, environmental and social impacts. The simultaneous or sequential occurrence of these extreme events can increase these impacts, and their frequency is expected to increase in many regions of the world. Moreover, the occurrence of hot days/nights was shown to be correlated to drought conditions in Mediterranean areas. Recently the catastrophic fire seasons of 2019/2020 in Australia has been pointed out to be associated with a drought exacerbation of the summer hot conditions. Additionally, temperature trends In Australia since 1970 are positive in most of the territory, whereas annual precipitation presents a negative trend in the East and a positive trend in the West.

In this work, we propose to analyze the relation between summer hot days/nights and antecedent drought conditions in Australia. The Standardized Precipitation Evapotranspiration Index (SPEI) at time-scales of 1 to 6 months was used to assess drought conditions. The indices Number of Hot Days (NHD) and Number of Hot Nights (NHN) were computed as the number of days on each month that exceed the 90th percentile of maximum and minimum temperatures, respectively. Data to compute these indices were retrieved from the ERA5 climate reanalysis dataset, and from the CRU TS4.03 dataset. Temperature data from the ACORN-SAT dataset was also used. A correlation analysis was performed between SPEI and NHD/NHH, using the concurrent months, and also the SPEI values on the previous 1 to 3 months. Significant negative correlations were obtained in southern regions. A probabilistic approach was also used, using copula functions, which allowed to estimate the joint probability of occurrence of dry and hot events.

Acknowledgements: This work was partially supported by projects FireCast (PCIF/GRF/0204/2017), and IMPECAF (PTDC/CTA-CLI/28902/2017). Andreia Ribeiro thanks FCT for the grant PD/BD/114481/2016.