bluuebunny/crossref_metadata_2025 huggingface dataset:
First investigations of fine-grained cryogenic cave carbonates from a High-Arctic permafrost karst system in Greenland
Authors: Donner Anika , Spötl Christoph , Töchterle Paul , Hajdas Irka , Moseley Gina E.
Published: March 2021

In recent years, cryogenic cave carbonates (CCC) have become the focus of studies tracking past climate change in periglacial environments. Two types of these speleothems occur, fine-grained CCC (CCCfine), which form due to the rapid freezing of a thin water film on ice, and coarse-grained CCC whose origin is related to the slow freezing of water pockets inside cave ice. Here, we report for the first time the occurrence of CCCfine from a cave in northeast Greenland, presently situated in continuous permafrost.

Eqik Qaarusussuaq (Cove Cave), located at 80.2° N, is a 103 m long, gently-dipping phreatic passage that was discovered during the 2019 Greenland Caves Project Expedition (www.greenlandcavesproject.org). CCCfine were found in a dry chamber 65 m behind the entrance. The cave air temperature at the CCC site of -14.7 °C contrasts with outside air temperatures of up to +18.0 °C in July 2019. This, together with current dry conditions at the sampling site, indicates that water infiltration, necessary for CCC formation, is not possible under present-day climate conditions. This is further supported by a lack of ice found within the cave.

Stable isotope analyses of CCC show δ18O values ranging from -21.9 to -16.0 ‰ and δ13C values between 8.4 and 11.7 ‰ VPDB. While the δ13C values are consistent with published data of CCCfine from caves at lower latitudes, the δ18O values are significantly lower and plot in the field of CCCcoarse (cf. Žák et al., 2018). This shift reflects the much lower δ18O values of meteoric precipitation in northeast Greenland compared to lower latitude sites.

Exploratory radiocarbon dating suggests that CCCfine formed in this High Arctic cave as recent as during the end of the Little Ice Age.

 

Reference

Žák, K., Onac, B.P., Kadebskaya, O.I., Filippi, M., Dublyansky, Y., Luetscher, M., 2018. Cryogenic mineral formation in caves. In: Perşoiu, A., Lauritzen, S.-E. (Eds.), Ice caves. Elsevier, Amsterdam, Netherlands, pp. 123–162.
US fluvial, pluvial and coastal flood hazard under current and future climates
Authors: Bates Paul , Quinn Niall , Sampson Christopher , Smith Andrew , Wing Oliver , Savage James , Olcese Gaia , Sosa Jeison , Neal Jeff
Published: March 2021

This talk reports a new and significantly enhanced analysis of US flood hazard at 30m spatial resolution.  For the first time we consider pluvial, fluvial and coastal flood hazards within the same framework and provide projections for both current (rather than historic average) conditions and for future time periods centred on 2035 and 2050 under the RCP4.5 emissions pathway.  Validation against high quality local models and the entire catalogue of FEMA 1% annual probability flood maps yielded Critical Success Index values in the range 0.69-0.82.  Significant improvements over a previous pluvial/fluvial model version are shown for high frequency events and coastal zones, along with minor improvements in areas where model performance was already good.  The result is the first comprehensive and consistent national scale analysis of flood hazard for the conterminous US for both current and future conditions.  Even though we consider a stabilization emissions scenario and a near future time horizon we project clear patterns of changing flood hazard (3σ changes in 100yr inundated area of -3.8 to +16% at 1° scale), that are significant when considered as a proportion of the land area where human use is possible or in terms of the currently protected land area where the standard of flood defence protection may become compromised by this time.
Do trade agreements activate new links and increase flows? A data-driven analysis of the global cereal market.
Authors: Falsetti Benedetta , Ridolfi Luca , Laio Francesco
Published: March 2021

Given the importance of food imports for food security and the role of exports in income generation, food trade is an indispensable component of most countries’ development strategies. Global and regional agreements set the rules for trade policies between countries. In this context, we investigate the impact of trade agreements on the trade network of agricultural products. We study whether the ratification of agricultural-oriented trade agreements has an influence on the topology of the cereal trade network (link establishment) and the variation of flows through existing links.

Our analysis differs from previous studies for three main reasons. Firstly, it is a data-driven analysis, based on a dataset that combines the trade agreement structure provided by the World Bank and cereal trade flow data from FAOSTAT. Secondly, the analysis focuses on a global scale, considering data for all countries where information is available. Finally, we carried out the analysis at the level of aggregated cereals, both from a monetary (US$) and diet-based (Kcal) perspective, over the period from 1993 to 2015. This time interval includes the most important recent reforms in the agricultural sector.

The results show that a new trade agreement between two countries increases the probability of activating a grain trade link by 7.3% in the year after the agreement is ratified. In the case where trade agreements are not considered, the probability of triggering a new link between two countries drops to 1.3%.

Regarding the volume of flows, we classify variations into three categories: flow decrease (negative variation of the flux), mild increase (<50% increase in the flow intensity), and sharp increase (>50% increase).

The results obtained, both in economic value (US$) and in quantitative variations (Kcal), show that the entry force of a trade agreement has two main effects: in flows covered by trade agreements, there is a significant increase in the percentage of flows experiencing a sharp increase, and a reduction of the percentage of flows experiencing a negative variation. 

We, therefore, provide here global-scale, data-based evidence. Previous results suggest that trade agreements are facilitators of the connections between different countries and, therefore, facilitators in terms of global food trade accessibility.  This work aims to be a first attempt to investigate the impacts of international agreements simultaneously on the topology of the agricultural product trade network, and on the increase of existing link flows. Our intention is to dedicate further analysis about which trade agreements perform better, increasing the traded volume, to explore the role of trade liberalization at a worldwide level.

 
Understory biomass estimation based on Structure from Motion data by Multi-layered forest drone survey
Authors: Zhang Yupan , Onda Yuichi , Kato Hiroaki , Sun Xinchao , Gomi Takashi
Published: March 2021

Understory vegetation is an important part of evapotranspiration from forest floor. Forest management changes the forest structure and then affects the understory vegetation biomass (UVB). Quantitative measurement and estimation of  UVB is a step cannot be ignored in the study of forest ecology and forest evapotranspiration. However, large-scale biomass measurement and estimation is challenging. In this study, Structure from Motion (SfM) was adopted simultaneously at two different layers in a plantation forest made by Japanese cedar and Japanese cypress to reconstruct forest structure from understory to above canopy: i) understory drone survey in a 1.1h sub-catchment to generate canopy height model (CHM) based on dense point clouds data derived from a manual low-flying drone under the canopy; ii) Above-canopy drone survey in whole catchment (33.2 ha) to compute canopy openness data based on point clouds of canopy derived from an autonomous flying drone above the canopy. Combined with actual biomass data from field harvesting to develop regression models between the CHM and UVB, which was then used to map spatial distribution of  UVB in sub-catchment. The relationship between UVB and canopy openness data was then developed by overlap analysis. This approach yielded high resolution understory over catchment scale with a point cloud density of more than 20 points/cm2. Strong coefficients of determination (R-squared = 0.75) of the cubic model supported prediction of UVB from CHM, the average UVB was 0.82kg/m2 and dominated by low ferns. The corresponding forest canopy openness in this area was 42.48% on average. Overlap analysis show no significant interactions between them in a cubic model with weak predictive power (R-squared < 0.46). Overall, we reconstructed the multi-layered structure of the forest and provided models of UVB. Understory survey has high accuracy for biomass measurement, but it’s inherently difficult to estimate UVB only based on canopy openness result.
The Central-East Atlantic Anomaly: its role in the genesis of the Canary and Madeira volcanic provinces
Authors: Custódio Susana , Civiero Chiara , Mata João , Silveira Graça , Neres Marta , Schlaphorst David
Published: March 2021

The Canary and Madeira provinces, located in the central-east Atlantic Ocean, are characterized by irregularly distributed hotspot tracks displaying large age differences and variable distances between volcanoes. For this reason, the geodynamic mechanism(s) that control the spatio-temporal patterns of volcanism are still unclear. Here, we use results from seismic tomography, shear-wave splitting, and gravity to show that the Central-East Atlantic Anomaly (CEAA), rising from the African large low-shear-velocity province and stalled in the topmost lower mantle, is the source of distinct upper-mantle diapirs feeding those provinces. The diapirs detach intermittently from the CEAA and seem to be at different evolutionary stages. Geochemistry data confirm the lower-mantle origin of the diapirs, and plate reconstructions constrain their temporal evolution. Our observations suggest that the accumulation of deep plume material in the topmost lower mantle can play a significant role in governing the spatio-temporal distribution of hotspot volcanism.

This is a contribution to project SIGHT (Ref. PTDC/CTA-GEF/30264/2017). The authors would like to acknowledge the financial support FCT through project UIDB/50019/2020 – IDL.
Stable sulfur isotope analysis of aerosol in Vilnius, Lithuania
Authors: Bučinskas Laurynas , Garbaras Andrius
Published: March 2021

Stable isotope analysis is important tool in investigation of SO2 and sulfate particulate matter chemical processes and provides valuable information on their transport, natural and anthropogenic pollution sources. Around half of atmospheric SO2 is oxidized to sulfate which can then form on existing aerosols or even nucleate to produce new particles [1], [2]. Physical and chemical processes cause fractionation of sulfur isotope ratios which helps us to differentiate between different sulfur sources.

The aim of this work was to examine δ34S distribution in atmospheric sulfate aerosol particles and to characterize their sources while applying stable isotope mass spectrometry methods. For this task, the dependence between measurements of atmospheric sulfate aerosol δ34S and particulate sulfate concentration was found. The sample collection was performed in Vilnius, Lithuania from 5 March until 6 May, during the year 2020. By comparing the aerosol sulfate concentrations to air monitoring data it was found that their values change accordingly to the background particulate matter concentrations in Vilnius, however changes in atmospheric SO2 concentrations produced little effect. Subsequently, relationship between δ34S values and aerosol sulfate concentrations was plotted which revealed two possible major sources of sulfate aerosol pollution. These results were then related to atmospheric air parcel trajectory models which were applied to help characterize the pollution sources and their effect on measured δ34S values.

The results of this work showed that during the sampling period atmospheric sulfate aerosol δ34S values ranged from 6,1 ‰ to 12,6 ‰. Additionally, it was determined that local pollution sources are represented by lower values of δ34S whereas long range source δ34S values are higher. Finally, two probable dominant sources of atmospheric sulfate aerosol pollution were found.

 

[1]  C. Tomasi, A. Lupi, „Primary and Secondary Sources of Atmospheric Aerosol“, Atmospheric Aerosols, 2016.

[2]  M. Chin, D. J. Jacob, G. M. Gardner, M. S. Foreman-Fowler, P. A. Spiro, D. L. Savoie, „A global three-dimensional model of tropospheric sulfate“, J. Geophys. Res. Atmos., 1996.
The Rashid rover: to guide the way for the next generation lunar missions and solar system exploration
Authors: Almaeeni Sara , Els Sebastian , Almarzooqi Hamad
Published: March 2021

The United Arab Emirates has announced its first space mission to the moon by 2024. The Emirates Lunar Mission (ELM) consists of a micro rover, named Rashid, has a main objective of traversing the mid-latitude landing site and obtaining high resolution images of the lunar surface. Such an objective necessitates careful designs of the architecture and the different systems involved to ensure smooth integration and proper operation.

The rover weigh around 10Kg and has 4 wheels that are designed to climb slopes of 20 degrees and rocks of maximum height of 10cm. Also, it is equipped with 2 wide field cameras that will be used for navigation and to increase the environmental awareness while the operator drives the rover remotely. Moreover, the rover is powered by the solar panels which are mounted in a certain angle to maximize the collecting of the solar energy. After the collection and battery charging, various regulated voltages are distributed to all subsystems.  

The Rashid rover is designed with two communications channels. The primary communications channel is the main channel used during the mission and allows for high speed bandwidth and low power consumption (on the rover). The secondary communications channel uses more power and is slower, but is not dependent on the lander and is therefore used as a backup as well as the lunar night recovery phase.

Despite being a small rover and its prime goal being a technology demonstrator, Rashid’s scientific instrument suite is substantial. The science instruments will provide data of the lunar surface environment allowing to investigate a vast variety of topics like geology of the Moon, lunar surface alteration mechanisms, Interaction of the soil with the solar wind and material suitability for future lunar missions. In this paper, the ELM mission, the rover subsystems as well as the science instruments are described in details.
Response of Northern Hemisphere weather and climate to Arctic sea ice decline: The role of resolution in Polar Amplification Model Intercomparison Project (PAMIP) simulations
Authors: Streffing Jan , Semmler Tido , Zampieri Lorenzo , Jung Thomas
Published: March 2021

The impact of Arctic sea ice decline on the weather and climate in mid-latitudes is still much debated, with observation suggesting a strong and models a much weaker link. In this study, we use the atmospheric model OpenIFS, in a set of model experiments following the protocol outlined in the Polar Amplification Model Intercomparison Project (PAMIP), to investigate whether the simulated atmospheric response to future changes in Arctic sea ice fundamentally depends on model resolution. More specifically, we increase the horizontal resolution of the model from 125km to 39km with 91 vertical levels; in a second step resolution is further increased to 16km with 137 levels in the vertical. We find that neither the mean atmospheric response nor the ensemble convergence toward the mean are strongly impacted by the model resolutions considered here.
Pristine metasomatic melt preserved in mantle rocks of the Bohemian Massif
Authors: Borghini Alessia , Ferrero Silvio , O'Brien Patrick J. , Wunder Bernd , Laurent Oscar
Published: March 2021

Melt inclusions of very unusual nature occur in garnets of eclogites of the Granulitgebirge, Bohemian Massif. This is one of the first direct characterization of a preserved metasomatic melt responsible for the formation of eclogites enclosed in garnet peridotites. The inclusions are micrometric, from glassy to fully crystalized as nanogranitoids and randomly distributed in the garnet core. Nanogranitoids contain kumdykolite/albite, phlogopite, osumilite and kokchetavite with a variable amount of quartz, pyroxene, carbonate and rare white mica. The melt has a granitic composition rather than basaltic or tonalitic/trondhjemitic as would be expected from the partial melting of ultramafic or mafic rocks and it is as well hydrous and peraluminous. The trace elements composition is also unusual for melts in mantle rocks with elements typical of continental crust (Cs, Li, B, Pb and Rb) and subduction zone (Th and U). Similar signatures, i.e. continental crust and subduction, are visible also in the whole rock trace elements in the form of high amounts of LILE and U. The eclogite major elements composition is similar to a Ca- and Fe - rich mafic rock akin more to the crust than to the mantle.

The peculiar melt composition and the lack of a clear residue of a melting reaction in the eclogites suggest that this melt is external, i.e. metasomatic. It infiltered the peridotites during subduction of the continental crust at mantle depth and aided the transformation of basic layers, already in the peridotite, to eclogite. In addition, similar trace elements patterns to the melt reported here can be found in the so-called durbachite -ultrapotassic melanosyenite present in the high-grade Variscan basement- and in the garnet peridotites and garnet pyroxenites of the T-7 borehole. In both case metasomatism was suggested but the agent was just inferred based on the geochemical signature. All these occurrences suggest that mantle contaminated by melts from deeply subducted continental crust is widespread beneath the Bohemian Massif.
Accurate ephemeris reconstruction for comet 67P/Churyumov-Gerasimenko from Rosetta data analysis
Authors: Lasagni Manghi Riccardo , Zannoni Marco , Tortora Paolo , Küppers Michael , O'Rourke Laurence , Martin Patrick , Mottola Stefano , Budnik Frank , Mackenzie Ruaraidh , Godard Bernard , Jorda Laurent , Groussin Olivier , Thomas Nicolas
Published: March 2021

Following its arrival at 67P/Churyumov-Gerasimenko in August 2014, the Rosetta spacecraft successfully navigated in proximity of the comet for two years, using a combination of radiometric measurements and optical images collected by the onboard navigation cameras.

The reconstructed spacecraft and comet trajectories were obtained combining several long-arc and short-arc orbit determination solutions generated by ESOC Flight Dynamics during the Rosetta operations. Several discontinuities are present within these trajectories, due to the lack of a dynamical model for the representation of the comet Non-Gravitational Accelerations (NGA).

The work presented in this study represents an effort to produce an accurate and continuous ephemeris reconstruction for comet 67P/Churyumov-Gerasimenko for the period between July 2014 and October 2016, through a complete reanalysis of the Range and ΔDOR measurements collected by Rosetta during its proximity phase with the comet.

Using as input the reconstructed relative orbit of Rosetta, the radiometric observables were mapped to the comet nucleus and used to estimate the comet state and some key physical and observational parameters within a Square Root Information batch filter implemented in MONTE, most notably the NGA acting on the comet nucleus due to surface outgassing.

Several orbit determination solutions were generated by varying the model used to represent the NGA. More specifically, empirical and stochastic models were compared by evaluating the reduced χ2 statistics of the measurement residuals to identify the most suitable trajectory estimations for each of the proposed models. From this narrow list of solutions, a preliminary selection for the final ephemeris reconstruction is proposed, based on its adherence to the original ESOC trajectory and on the consistency of the formal state uncertainties with the estimated solutions.

It will be shown that the selected ephemeris solution, using a piecewise linear stochastic NGA model with intervals between 3 and 4 weeks, produces a continuous ephemeris reconstruction for 67P/Churyumov-Gerasimenko with maximum formal uncertainties around perihelion of σpos ≅ [20 km, 30 km, 200 km] in the Radial-Tangential-Normal reference frame. The advantage of using simple stochastic models, with limited a-priori assumptions on the involved physical processes, is that they allow to produce an unbiased estimation of the NGA variations around perihelion, which represent a valuable input for further investigations involving detailed physical models of the cometary activity.
Assessment of precipitation extremes in CMIP6 decadal hindcasts over India
Authors: Patel Jayshri , Chellappan Gnanaseelan , Parekh Anant , Chowdhary jasti
Published: March 2021

A skillful decadal precipitation prediction (DPP) is valuable for sustainable development, which currently face many challenges.Deriving reliable information from DPP is still a challenge because of the difficulties linked with precipitation predictions and coarse spatial resolution by General Circulation Models (GCMs) not able to be in a straight line appropriate for impact assessment.This study examines the decadal hindcast simulations of precipitation extreme over seven sub regions of India from different ocean-atmosphere coupled models from the Coupled Model Intercomparison Project(CMIP6) by applying quantile mapping approach.Each decadal hindcast consists of predictions for a 10-year period from the initial climate states of 1961 to 2014/2018 and the assessment of skill is carried out lead-wise from 1 to 10 for different season and different regions over India (both raw and bias corrected). The potential skill of precipitation extreme is examined in terms of  extreme precipitation index (EPIs) i.e.cumulative wet days (CWD), cumulative dry days (CDD), precipitation events between P1020(10 and 20 mm),P20P40(20 and 40 mm), PG40(>40 mm) and  annual maximum 1 & 5 day precipitation (Rx1day and Rx5day). The promising results revealed that the skills of DPPs are enhanced after the bias adjustment and the data product can be used as a key input for impacts assessments in the region.

 
The Utrecht Finite Volume Ice-Sheet Model: UFEMISM
Authors: Berends Tijn , van de Wal Roderik , Goelzer Heiko
Published: March 2021

Improving our confidence in future projections of sea-level rise requires models that can simulate ice-sheet evolution both in the future and in the geological past. A physically accurate treatment of large changes in ice-sheet geometry requires a proper treatment of processes near the margin, like grounding line dynamics, which in turn requires a high spatial resolution in that specific region. This leads to a demand for computationally efficient models, where such a high resolution can be feasibly applied in simulations of 105 – 107 yr in duration. To solve this, we developed UFEMISM, a new ice-sheet model that solves the hybrid SIA/SSA approximation of the stress balance on a fully adaptive, unstructured triangular mesh. This strongly reduces the number of grid points where the equations need to be solved, making the model much faster than the square-grid models that are typically used in paleo-ice-sheet research. We will discuss some of the difficulties in developing such a model, and the solutions we came up with. We will show that the model successfully performs several common schematic benchmark experiments for ice-sheet models, and we will take a look at some preliminary results of realistic experiments.
Influence of Nordic Seas dynamics on the Atlantic Water propagation and its impacts on sea ice concentration.
Authors: Chatterjee Sourav , Raj Roshin P , Bertino Laurent , Murukesh Nuncio
Published: March 2021

Enhanced intrusion of warm and saline Atlantic Water (AW) to the Arctic Ocean (AO) in recent years has drawn wide interest of the scientific community owing to its potential role in ‘Arctic Amplification’. Not only the AW has warmed over the last few decades , but its transfer efficiency have also undergone significant modifications due to changes in atmosphere and ocean dynamics at regional to large scales. The Nordic Seas (NS), in this regard, play a vital role as the major exchange of polar and sub-polar waters takes place in this region. Further, the AW and its significant modification on its way to AO via the Nordic Seas has large scale implications on e.g., deep water formation, air-sea heat fluxes. Previous studies have suggested that a change in the sub-polar gyre dynamics in the North Atlantic controls the AW anomalies that enter the NS and eventually end up in the AO. However, the role of NS dynamics in resulting in the modifications of these AW anomalies are not well studied. Here in this study, we show that the Nordic Seas are not only a passive conduit of AW anomalies but the ocean circulations in the Nordic Seas, particularly the Greenland Sea Gyre (GSG) circulation can significantly change the AW characteristics between the entry and exit point of AW in the NS. Further, it is shown that the change in GSG circulation can modify the AW heat distribution in the Nordic Seas and can potentially influence the sea ice concentration therein. Projected enhanced atmospheric forcing in the NS in a warming Arctic scenario and the warming trend of the AW can amplify the role of NS circulation in AW propagation and its impact on sea ice, freshwater budget and deep water formation.
The future decline in lake levels puts an evolutionary giant at risk
Authors: Prange Matthias , Nandini-Weiss Sri , Wilke Thomas , Wesselingh Frank
Published: March 2021

Continental drying in response to global warming will entail declining lake levels all over the world. Falling lake levels will have many far-reaching consequences that are underappreciated, but affect the livelihoods and economies of millions of people. A massive warning signal is the projected twenty-first century water level drop of up to 18 m in high emissions scenarios for the Caspian Sea, the largest lake in the world, which could hit stakeholders unprepared. Such a catastrophic drop in the Caspian Sea level would lead to a surface area decrease of 34% including the loss of the highly productive northern Caspian shelf and important wetlands such as the Volga Delta and other Ramsar sites. The disappearance of the vast shallow shelves, which are major food suppliers for fish and birds, will devastate native and endemic fish species, the Caspian seal and a richness of molluscs and crustacean species unique to the lake. The falling water level will not only threaten the unique ecosystem, but will also have severe impacts on regional economies and geopolitical stability.

In the first part of this presentation, we discuss the extent of twenty-first century projected continental drying on a global scale and its potential effect on worldwide lake levels. In the second part, we focus on the Caspian Sea and discuss the potential impacts of water level fall on biodiversity and ecosystem services. Finally, we address the question to which extent paleoclimates can be used as analogs for future global warming scenarios with respect to changes in the Caspian Sea level.
Using sedaDNA to reconstruct planktonic communities across 385’000 years old marine sedimentary core from a tropical sea.
Authors: Barrenechea Angeles Ines , Beaufort Luc , Ariztegui Daniel , Pawlowski Jan
Published: March 2021

Sedimentary ancient DNA (sedaDNA) is becoming a paleo-proxy of choice for many marine environments. However, there are few studies from tropical sites and even fewer from tropical marine sediments exposed to factors damaging the DNA such as elevated sea surface water temperature or UV radiation. Here, we report successful extraction of DNA from a marine sedimentary core retrieved from the Bismarck Sea, off New Papua Guinea, where the mean annual temperature is about 29°C. The core MD05-2920 covers the last 385 000 years. We analyzed samples from 20 layers, where the isotopic measures of δ18O isotopic composition of benthic foraminifera show significant palaeoceanographic changes from glacial to interglacial periods. We apply a metabarcoding approach using specific 18S primers for planktonic foraminifera, diatoms, and radiolarians. Even if the amount of DNA declines throughout the core, the patterns of successional changes in species communities of these three taxonomic groups are well archived. Our study shows that it is possible to reconstruct the planktonic community even from very old sedaDNA samples from a tropical marine sedimentary core.
Blast vibration reduction
Authors: Trabi Bernd , Bleibinhaus Florian , Tauchner Cornelia
Published: March 2021

Blasting operations in quarries are accompanied by ground vibrations which can endanger buildings nearby. A production blast is made of several holes with a small distance to each other, which are blasted with a time delay, for the purpose of production and to reduce the ground vibrations. These production blasts produce a specific radiation pattern. It would be favorable to focus the ground vibrations to a less sensitive direction or area. We want to be able to predict the ground vibrations for a realistic inhomogeneous case at an area around the iron ore mine at mount Erzberg in Austria. Therefore a numerical forward modeling on a 3D model of the iron ore mine and its surrounding area was performed with a 3D elastic code with topography. The 3D model itself is the result of a tomographic travel time inversion. One problem is that the spectral response of a single blast is unknown and therefore we had to find a transfer function which transfers the numeric spectral response to the observed spectral response. After applying the transfer function the amplitude spectra of the numerical solution show a good match to the amplitude spectra of the observed production blasts. In this study, we investigate, if a reduction of ground vibrations can be achieved by blasting simultaneously two arrays with optimized time delays. To achieve that optimized time delays we developed a global search algorithm, based on Markov chain Monte Carlo method which finds potential blast configurations, with minimum impact to critical locations near the quarry. This study is part of the EU-funded project SLIM (Sustainable Low Impact Mining, www.slim-project.eu).
WISDOM Antenna Pattern in the presence of Rover and Soil
Authors: Benedix Wolf-Stefan , Plettemeier Dirk , Statz Christoph , Lu Yun , Hahnel Ronny , Ciarletti Valérie
Published: March 2021

The WISDOM ground-penetrating radar aboard the 2022 ESA-Roscosmos Rosalind-Franklin ExoMars Rover will probe the shallow subsurface of Oxia Planum using electromagnetic waves. A dual-polarized broadband antenna assembly transmits the WISDOM signal into the Martian subsurface and receives the return signal. This antenna assembly has been extensively tested and characterized w.r.t. the most significant antenna parameters (gain, pattern, matching). However, during the design phase, these parameters were simulated or measured without the environment, i.e., in the absence of other objects like brackets, rover vehicle, or soil. Some measurements of the rover's influence on the WISDOM data were performed during the instrument's integration.

It was shown that the rover structure and close surroundings in the near-field region of the WISDOM antenna assembly have a significant impact on the WISDOM signal and sounding performance. Hence, it is essential to include the simulations' environment, especially with varying surface and underground.

With this contribution, we outline the influences of rover and ground on the antenna's pattern and particularly on the footprint. We employ a 3D field solver with a complete system model above different soil types, i.e., subsurface materials with various combinations of permittivity and conductivity.
P-PINI: a new inversion method for sediment-burial dating
Authors: Nørgaard Jesper , Jansen John , Neuhuber Stephanie , Ruszkizcay-Rüdiger Zsófia , Braumann Sandra , Feibig Markus , Häuselmann Philipp , Faurschou Knudsen Mads
Published: March 2021

For sediment-burial dating with a cosmogenic nuclide pair, the isochron burial method performs well provided that the sediment source has undergone (1) steady erosion and (2) continuous exposure to cosmic rays. These conditions exert important limitations on applications of the method. And yet, in mountainous fluvial and glacial landscapes, it is commonly found that the source area has experienced landsliding or glacial quarrying (i.e., non-steady erosion), and/or intermittent sediment storage or burial beneath glaciers (i.e., discontinuous exposure). As well as breaching the assumptions of the isochron method, such processes tend to yield low nuclide concentrations in the sample, which further limits its workability.

Here we present a more flexible method that accommodates complex, non-steady pre-burial erosion and exposure histories: conditions that exclude the isochron burial method. P-PINI (Particle Pathway Inversion of Nuclide Inventories) is a Monte Carlo-based inversion model that employs a source-to-sink approach for estimating the depositional age of fluvial and glaciogenic sediments. This method has been successfully applied to the Deckenschotter in the northern Alpine foreland (see Knudsen et al. 2020, Earth & Planetary Science Letters 549, 116491). As with the isochron burial method, P-PINI exploits an ensemble of paired nuclide (e.g., 10Be-26Al) concentrations measured in different samples from the same depth in a sedimentary sequence. But unlike the isochron method, P-PINI applies a stochastic approach to simulate a wide range of possible pre-depositional exposure and erosion histories for each individual sample. These different pre-burial histories (unique to each sample) are then integrated with the constraint that all samples share a common burial history at the sink. Where cosmogenic nuclide data (or other chronometric data, e.g., OSL) are available for multiple sites, Bayesian inference modelling can impose a priori relative age constraints, or estimates on the maximum duration of sediment storage.

In this presentation, we extend P-PINI to explore how sediment storage and reworking (i.e., a range of burial depths and durations) between source and sink affects burial age estimates. Significant intermediate storage is characteristic of large river systems, such as the Danube River. Using cosmogenic 10Be-26Al concentrations measured in fluvial gravels at Gänserndorf and Schlosshof, two terraces along the Danube River in the Vienna Basin (Braumann et al., 2019. Quat. Int. 509. 87-102), we examine how the burial ages at these two sites are a function of the pre-burial history experienced by the samples.  
Two reduced models for reactive flows in fractured porous media
Authors: Fumagalli Alessio , Scotti Anna
Published: March 2021

In the simulation of many porous media applications, such as geothermal energy, CO2 and nuclear waste storage and groundwater management, transport and reaction processes are fundamental to make accurate and reliable predictions. Moreover, the fractures present in the undeground, with their physical properties (high/low conductivity) and complex geometry are of paramount importance, on one side, but extremely complex to handle on the other. We propose two models based on a geometrical reduction procedure that approximate fractures as objects of lower dimension forming thus a system of mixed-dimensional partial differential equation. The first model describes a thermal reactive flow problem in both the fractures and porous media, coupled with suitable interface conditions. Chemical reactions can change porosity and fracture aperture with dissolution and precipitation of minerals. To obtain the solution for each time step, we consider a splitting strategy so that each physical process is solved sequentially ensuring, at the discrete level, mass conservation.  The second model in addition accounts for a thin layer of porous media surrounding the fractures where the effect of chemical reactions is prevalent, approximating it with a line/surface coupled with the fracture. Its thickness, which may change in time, is estimated with a mono-dimensional equation solved in the direction normal to the fracture. Comparison with the equi-dimensional problem ensure the quality of the proposed models.
3D Digital Outcrop Model analysis of fracture networks: insights from the Mt. Vettore Fault Zone.
Authors: Inama Riccardo , Panara Yuri , Menegoni Niccolò , Carboni Filippo , Toscani Giovanni , Brunori Carlo Alberto , Perotti Cesare
Published: March 2021

In the last years, several studies investigated the Mt. Vettore Fault Zone (MVFZ), activated during the 2016 Central Italy seismic sequence. Research has focused mainly on aftershocks and mainshock locations, coseismic slip and surface cracks, while an accurate study of the fracture network in the MVFZ was never conducted.

In this study we present a fracture analysis performed using very high resolution (0.5 – 5 cm) Digital Outcrop Models (DOMs) that developed by Unmanned Aerial Vehicle (UAV)-based digital photogrammetry. The UAV gave the possibility to investigate outcrops with dimensions up to hundreds of metres high and wide, and acquire big and precise fracture data using 3D digital automatic and manual mapping techniques. To investigate the structural variability of the MVFZ fracture network, we realized several DOMs located in different positions, along and around the major fault. All the selected outcrops are formed by Calcare Massiccio Fm., which better records brittle deformation in the study area.

This analysis aimed to better understand the MVFZ fracture network, including mechanics, kinematics and local structural evolution. In particular, it allowed to determine: 1) the main sets of fractures; 2) the geometrical parameters of the fracture network (e.g. fracture density, persistence, roughness and aperture); 3) the relative timing of the main tectonic brittle events. The preliminary analysis of the DOMs suggests a variability of the fracture network parameters over the MVFZ, especially for what concerned fracture set orientation and density. 

 

 
Uncertainty of Tropical Cyclone Wind Radii on Sea Surface Temperature Cooling
Authors: Pun Iam-Fei , Knaff John , Sampson Charles
Published: March 2021

The sea surface temperature (SST) beneath a tropical cyclone (TC) is of great importance to its dynamics; therefore, understanding and accurately estimating the magnitude of SST cooling is of vital importance.  Existing studies have explored important influences on SST such as TC translation speed, maximum surface winds, ocean thermal condition and ocean stratification.  But the influence of the TC wind radii (or collectively called the TC size) on SST has been largely overlooked.  In this study we assess the influence of wind radii uncertainty on SST cooling by a total of 15,983 numerical simulations for the western North Pacific during the 2014-2018 seasons.  Results show a 6-20% SST cooling error induced using wind radii from the Joint Typhoon Warning Center official forecast and a 35-40% SST cooling error using wind radii from the operational runs of the Hurricane Weather Research and Forecasting (HWRF) model.  Our results indicate that SST cooling is most sensitive to the radius of 64 kt winds.  The correlation between SST cooling induced by the TC and its size is 0.49, which is highest among all the parameters tested.  This suggests that it is extremely important to get TC size correct in order to predict the SST cooling response, which then impacts TC evolution in numerical weather prediction models.
Driving a Convection Parametrization with EUREC4A Observations
Authors: Saffin Leo , Denby Leif , Blyth Alan
Published: March 2021

A main aim of the EUREC4A project is to better understand the interaction clouds and convection with changes in the circulation. A key part of this uncertainty in models is the response of the convection parametrization to changes in the grid-scale forcing. This uncertainty can be difficult to isolate due to the complexity of models leading to many competing errors. The comprehensive observations taken during the EUREC4A field campaign give us the opportunity to run convection parametrizations directly from observations. I will show the response of the Met Office's new convection parametrization (CoMorph) to profiles derived directly from EUREC4A observations. Initial tests with the dropsonde dataset (JOANNE), show that CoMorph can produce realistic forcing within the observational uncertainty. The aim is to include more observations into this framework to identify area in which the convection parametrization can be improved.
Investigating monoterpene ozonolysis reactions in the mobile DouAir atmospheric simulation chamber: field and laboratory experiments
Authors: Lahib Ahmad , Bouzidi Hichem , Reijrink Nina , Duncianu Marius , Perraudin Emilie , Flaud Pierre-Marie , Villenave Eric , Williams Jonathan , Tomas Alexandre , Dusanter Sebastien
Published: March 2021

The chemistry of the atmosphere is usually studied using three different approaches, i.e. field measurements, laboratory studies and chemical model calculations. All three are complementary and powerful means to investigate chemical transformations of pollutants and improve our understanding of the atmosphere. Atmospheric simulation chambers are one of the most direct and critical approaches to mimic and examine chemical transformations under controlled experimental conditions. In combination with box model simulations, they allow assessment of the accuracy of chemical mechanisms implemented in atmospheric models.

During the CERVOLAND field campaign (Characterisation of Emissions and Reactivity of Volatile Organic compounds in the LANDes forest) we deployed a new mobile atmospheric chamber (DouAir) to probe the oxidation of biogenic volatile organic compounds (BVOCs) in real air masses. Biogenic compounds emitted by the surrounding forest (mainly pines - (Maritime pine, Pinus pinaster Ait) were trapped in DouAir and their transformations were probed using state-of-the-art online instrumentation, including PTR-ToF-MS (VOCs), PERCA (peroxy radicals), O3 and NOx analysers, and SMPS (aerosols).

The objectives of the present study were to (1) reproduce in the laboratory selected field experiments performed during CERVOLAND, the chemical composition of the air mass being simplified, and (2) compare both the field and laboratory results to 0-D box model simulations using the Master Chemical Mechanisms (MCM). Comparing field observations, laboratory experiments and model simulations provides a critical test of our understanding of atmospheric oxidation processes involving biogenic compounds.

Here, we present ozonolysis experiments of primary biogenic VOCs (mainly monoterpenes) under dark conditions. Initial conditions used for the laboratory experiments were derived from reactant concentrations trapped in DouAir during CERVOLAND. The results show the capability of the model to reproduce oxidation rates of primary VOCs within uncertainty, although the model considerably overestimates measured peroxy radical concentrations. The addition of rapid self- and cross-reactions of monoterpene-derived peroxy radicals in the MCM improves the agreement with the measured peroxy radical concentrations.
A step forward toward the high-resolution assessment of virtual water flows at the company’s scale
Authors: De Petrillo Elena , Tuninetti Marta , Laio Francesco
Published: March 2021

Through the international trade of agricultural goods, water resources that are physically used in the country of production are virtually transferred to the country of consumption. Food trade leads to a global redistribution of freshwater resources, thus shaping distant interdependencies among countries. Recent studies have shown how agricultural trade drives an outsourcing of environmental impacts pertaining to depletion and pollution of freshwater resources, and eutrophication of river bodies in distant producer countries. What is less clear is how the final consumer – being an individual, a company, or a community- impacts the water resources of producer countries at a subnational scale. Indeed, the variability of sub-national water footprint (WF in m3/tonne) due to climate, soil properties, irrigation practices, and fertilizer inputs is generally lost in trade analyses, as most trade data are only available at the country scale. The latest version of the Spatially Explicit Information on Production to Consumption Systems model  (SEI-PCS) by Trase provides detailed data on single trade flows (in tonne) along the crop supply chain: from local municipalities- to exporter companies- to importer companies – to the final consumer countries. These data allow us to capitalize on the high-resolution data of agricultural WF available in the literature, in order to quantify the sub-national virtual water flows behind food trade. As a first step, we assess the detailed soybean trade between Brazil and Italy. This assessment is relevant for water management because the global soybean flow reaching Italy may be traced back to 374 municipalities with heterogeneous agricultural practises and water use efficiency. Results show that the largest flow of virtual water from a Brazilian municipality to Italy -3.52e+07 m3 (3% of the total export flow)- comes from Sorriso in the State of Mato Grosso. Conversely, the highest flow of blue water -1.56e+05 m3- comes from Jaguarão, in the State of Rio Grande do Sul, located in the Brazilian Pampa. Further, the analysis at the company scale reveals that as many as 37 exporting companies can be identified exchanging to Italy;  Bianchini S.A is the largest virtual water trader (1.88 e+08 m3 of green water and 3,92 e+06 m3 of blue water), followed by COFCO (1,06 e+08 m3 of green water and 6.62 m3 of blue water)  and Cargill ( 6.96 e+07 m3 of green water and 2.80 e+02 m3 of blue water). By building the bipartite network of importing companies and municipalities originating the fluxes we are able to efficiently disaggregate the supply chains , providing novel tools to build sustainable water management strategies.
Proof of Concept with Distributed Temperature Sensing for Crack Detection on Dikes
Authors: Duarte Campos Leonardo , Aguilar López Juan Pablo
Published: March 2021

Cracks occurring on dike surfaces due to droughts, are a big threat for the safety of flood defence infrastructure as they increase infiltration rates and reduce the resistance to mass rotational failure (slope stability). Hence, an effective and sustainable monitoring system for crack detection is of paramount importance given the increase in frequency of drought events. Conventional methods heavily rely on visual inspections by expert observers, drone technologies survey, or destructive techniques such as sampling and trenching. Most of them result sparse qualitative and labor-intensive assessments. In this project, we aim to develop a method which combines two different sensing techniques —distributed temperature sensing (DTS) and conventional video cameras— for detecting the cracks on the dike surface. In contrast to earlier studies using DTS to measure the temperature changes during high water levels in the riverside slope and to detect seepage changes, we will be measuring the superficial moisture content on the riverside and the landside slopes of the dike, and use it as a proxy for crack detection in combination with the camera images and deep learning techniques. It is expected that by including the DTS measurements, the detection of cracks may outperform the actual methods in an economically and more densely manner along several kilometers of dikes in real time.