bluuebunny/crossref_metadata_2025 huggingface dataset:
Global Heritage Stones Resource: An IUGS designation
Authors: Kaur Gurmeet , Cardenes Victor
Published: March 2021

The initiative of designating the natural stones as Global Heritage Stones Resource by the IUGS is a novel one. The stakeholders are all those countries which record the stone built monuments of cultural significance. The stones used in the monuments with unique geological and architectural attributes and which have been used in the historical past with surviving and/or extinct quarries are being considered for designation of GHSRs. The European nations have been quick in identifying such stones and have proposed many significant stones for designation of GHSR in stark contrast to African, Asian and South American nations which are underrepresented on the world map in terms of designation of GHSR. The need of the hour is to promote the idea to all the nations to come up with the documentation of the stones used in the monuments, the state of preservation of historical quarries, the record and strategy for the upkeep of monuments and the historical quarries. The Project ‘The HERITAGE STONES RECOGNITION: A STEP FORWARD (HerSTONES)’ has been recently granted by IGCP-UNESCO to promote heritage Stones from emerging countries.
Magnetostratigraphy from the Hominin Sites Paleolakes Drilling Project (HSPDP) drill cores, low latitudes reorientation
Authors: Sier Mark Jan , Dupont-Nivet Guillaume , Langereis Cor , Cohen Andy ,   HSPDP science team
Published: March 2021

The Hominin Sites Paleolakes Drilling project (HSPDP) has collected around 2000 meters of drilled cores in lake sediment in Kenya and Ethiopia. All cores were drilled near important sites in human evolution with as main goal to help us better understand the influence of climate change on our evolutionary past.

An important first step in this research is building an age-model for these cores with magnetostratigraphy being important building block. However, building a magnetostratigraphy for the HSPDP cores is not straightforward. Due to the rotational movement of the coring process the azimuthal orientations of the cores is lost. This hinders the construction of magnetostratigraphy based of correctly orientated paleomagnetic samples. For high latitudes a high quality magnetostratigraphy can be reconstructed on the basis of the inclination of the paleomagnetic direction.

However, at low latitudes near the equator the inclination of the (paleo) magnetic field are near zero. As a result a magnetostratigraphy on the basis of inclination alone cannot be made.

In this presentation we discuss two methods that can be used to build a core based magnetostratigraphy at low latitudes. First, the anisotropy of the magnetic susceptibility (AMS) can be used in certain cases to reorientate the paleomagnetic samples by identifying the bedding of the sediments throughout the core.

Second, the present/recent low temperatures –low coercivity (LT/LC) overprint can be used to reorientate the paleomagnetic directions by orientating these LT/LC components towards the north and recalculate the paleomagnetic directions.

Both methods have been used on the ICDP Hominin Sites Paleolakes Drilling Project (HSPDP) cores taken in Ethiopia and Kenia with varied success. Here we will present data of four HSPDP cores as case study to help illustrate the effectiveness of these two methods for building a magnetostratigraphy for low latitude cores.
Hydroclimatic Controls on Salt Fluxes and Halite Deposition in the Dead Sea and the Shaping of “Salt Giants”
Authors: Sirota Ido , Ouillon Raphael , Mor Ziv , Meiburg Eckart , Enzel Yehouda , Arnon Ali , Lensky Nadav
Published: March 2021

As the only deep hypersaline, halite‐precipitating lake on Earth today, the Dead Sea is the
single modern analog for investigating the mechanisms by which large‐scale and thick salt deposits,
known as “salt giants”, have accreted in the geological record. We directly measure the hydroclimatic forcing
and the physical limnologic processes leading to halite sedimentation, the vertical thermohaline structure,
and salt fluxes in the Dead Sea. We demonstrate that changes in these forcing lead to strong seasonal
and regional variations in the stratification stability ratio, triggering corresponding spatiotemporal
variations in thermohaline staircase formation and diapycnal salt flux, and finally control the thickness of
the halite layer deposited. The observed staircase formation is consistent with the mean‐field γ instability,
causing layering in double‐diffusive convection. We show that double diffusion and thermohaline staircase
formation drive the spatial variability of halite deposition in hypersaline water bodies, underlying and
shaping “salt giants” basin architecture.
Evolution of stream interaction regions from 1 to 1.5 AU
Authors: Geyer Paul , Temmer Manuela , Guo Jingnan , Heinemann Stephan
Published: March 2021

We inspect the evolution of stream interaction regions from Earth to Mars for the declining solar cycle 24. In particular, the opposition phases of the two planets are analyzed in more detail. So far, there is no study comparing the long-term properties of stream interaction regions and accompanying high-speed streams at both planets for the same time period. We build a catalogue covering a dataset of all measured stream interaction regions at Earth and Mars for the time period December 2014 – November 2018. The number of events (>120) allows for a strong statistical basis. To build the catalogue we use near-earth OMNI data as well as measurements from the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft. For the opposition phase, we additionally use image data from the Solar Dynamics Observatory to complement the in-situ observations. Bulk speed, proton density, temperature, magnetic field magnitude and total perpendicular pressure are statistically evaluated using a superposed epoch analysis. For the opposition phase, coronal holes that are linked to individual streams are identified. The extracted coronal hole areas (using CATCH) and their longitudinal/latitudinal extension are correlated to the duration and maximum bulk speed of the high-speed stream following the passage of a stream interaction region. We find that an expansion of the stream interface from 1 to 1.5 AU is most visible in magnetic field and total perpendicular pressure. The duration of the high-speed stream does not increase significantly from Earth to Mars, however, the stream crest seems to increase. The amplitudes of the SW parameters are found to only slightly increase or stagnate from 1 – 1.5 AU. We arrive at similar correlation coefficients for both planets with the properties of the related coronal holes. There is a stronger linking of maximum bulk speed to latitudinal extent of the coronal hole than to the longitudinal. On average, the occurrence rate of fast forward shocks increases from Earth to Mars.
Rock and Roll: RFID Tracking of Fluvial Bedload Transport and Interaction with Large Wood 
Authors: Clark Miles , Bennett Georgie , Franco Aldina , Ryan-Burkett Sandra , Sear David
Published: March 2021

Bedload transport is a fundamental process by which coarse sediment is transferred through landscapes by river networks and is characterized by cyclic sequences of particle motion and rest. Bedload transport has many complex physical controls but may be well described stochastically by distributions of grain step length and rest time obtained through tracer studies. To date, none of these published tracer studies have specifically investigated the influence of large wood on distributions of step length or rest time, limiting the applicability of stochastic sediment transport models in these settings. Large wood is a major component of many forested rivers and is increasing because of disturbances such as wildfire and insect infestations as well as its use in rivers as part of ‘Natural Food Management’ (NFM) practice. This study aims to investigate and model the influence of large wood on grain-scale bedload transport. 

St Louis Creek, an alpine stream in the Fraser Experimental Forest, Colorado, is experiencing increased wood loading resulting from the infestation of the mountain pine beetle in the past decades. We inserted 957 Passive Integrative Transponders (PIT) tagged cobbles in 2016 upstream of a wood loaded reach and measured and tagged > 20 pieces of large wood in the channel. We resurveyed the cobbles and wood on an annual basis after snowmelt, building distributions of rock-step lengths as well as observing any changes and transport of large wood. Additionally, a novel modelling approach based on linear mixed modelling (LMM) statistical approaches is implemented to establish the significance of wood and other factors on probability of particle entrainment, deposition and step length.

Tracer sediments accumulated both up and downstream of large wood pieces, with LMM analysis confirming a reduction in the probability of entrainment of tracers closer to wood. In addition, when tracers were remobilised, their subsequent step lengths were shorter the closer they were deposited to large wood. In 2019, large wood significantly reduced the step lengths of tracer particles, forcing premature deposition of tracers. This study demonstrates the role of large wood in influencing bedload transport in alpine stream environments, with implications for both natural and anthropogenic addition of wood debris in fluvial environments.
Supporting successful data and codes sharing practices in agrogeophysics
Authors: Iván Veronika , Mary Benjamin , Blanchy Guillaume , Weigand Maximillian , Garré Sarah
Published: March 2021

Agrogeophysics comprises the use of geophysical methods applied to near surface agricultural problems. It is an interdisciplinary field which has been gaining momentum given the many advantages of geophysical tools for agriculture: non-invasiveness, large volume sample with reasonable spatial resolution, high-throughput, time-lapse possibility. In order to federate the agrogeophysical community and provide an overview of the field to researchers, we developed the catalog of agrogeophysical studies (CAGS). The catalog and its content is available under open licences and promotes practices that implement the FAIR Data Principles. These principles encourage progress toward sharing data and codes that are Findable, Accessible, Interoperable, and Reusable. The biggest strength of the CAGS is that it provides an overview of the current research state while providing metadata, associated datasets, and computational notebooks connected to the articles in which they were published. In this way, CAGS encourages reproducible research by providing the datasets and processing steps to reproduce the results of the papers. The ambition is to ultimately unite the agrogeophysical community around common standards for data processing and data interpretation. The website is hosted on GitHub (https://agrogeophy.github.io/catalog/). The open nature of CAGS and the possibility for everyone to contribute to it makes it a great platform to increase knowledge exchange across the different various international research teams.

Benjamin Mary, and Guillaume Blanchy. 2020. CAGS: Catalog of Agrogeophysical Studies. doi: 10.5281/zenodo.4058524.
Band-limited scattered wavefield reconstruction beneath complex overburdens using the Marchenko method
Authors: Vargas David , Vasconcelos Ivan , Ravasi Matteo
Published: March 2021

Structural imaging beneath complex overburdens, such as sub-salt or sub-basalt, typically characterized by high-impedance contrasts represents a major challenge for state-of-the-art seismic methods. Reconstructing complex geological structures in the vicinity of and below salt bodies is challenging not only due to uneven, single-sided illumination of the target area but also because of the imperfect removal of surface and internal multiples from the recorded data, as required by traditional migration algorithms. In such tectonic setups, most of the downgoing seismic wavefield is reflected toward the surface when interacting with the overburden's top layer. Similarly, the sub-salt upcoming energy is backscattered at the salt's base. Consequently, the actual energy illuminating the sub-salt reflectors, recorded at the surface, is around the noise level. In diapiric trap systems, conventional seismic extrapolation techniques do not guarantee sufficient quality to reduce exploration and production risks; likewise, seismic-based reservoir characterization and monitoring are also compromised. In this regard, accurate wavefield extrapolation techniques based on the Marchenko method may open up new ways to exploit seismic data.

The Marchenko redatuming technique retrieves reliable full-wavefield information in the presence of geologic intrusions, which can be subsequently used to produce artefact-free images by naturally including all orders of multiples present in seismic reflection data. To achieve such a goal, the method relies on the estimation of focusing operators allowing the synthesis of virtual surveys at a given depth level. Still, current Marchenko implementations do not fully incorporate available subsurface models with sharp contrasts, due to the requirements regarding the initialization of the focusing functions. Most importantly, in complex media, even a fairly accurate estimation of a direct wave as a proxy for the required initial focusing functions may not be enough to guarantee sufficiently accurate wavefield reconstruction.

In this talk, we will discuss a scattering-based Marchenko redatuming framework which improves the redatuming of seismic surface data in highly complex media when compared to other Marchenko-based schemes. This extended version is designed to accommodate for band-limited, multi-component, and possibly unevenly sampled seismic data, which contain both free-surface and internal multiples, whilst requiring minimum pre-processing steps. The performance of our scattering Marchenko method will be evaluated using a comprehensive set of numerical tests on a complex 2D subsalt model.
Innovative urban climate model PALM-4U as a support tool for municipal climate adaptation strategies.
Authors: Kriuger Antonina , Reinbold Alexander , Schubert-Frisius Martina , Cortekar Jörg
Published: March 2021

Cities are particularly vulnerable to climate change. At the same time, cities change slowly. Accordingly, preparatory measures to adapt to climate change have to be taken urgently. High-performance urban climate models with various applications can form the basis for prospective planning decisions, however, as of today no such model exists that can be easily applied outside of the scientific community. Therefore, the funding program Urban Climate Under Change [UC]2 aims to further develop the new urban climate model PALM-4U (Parallelized Large-Eddy Simulation Model for Urban Applications) into a practice-oriented and user-friendly product that meets the needs of municipalities and other practical users in addition to scientific research.

Specifically, the high-performance model PALM-4U allows simulation of entire large cities comprising the area over 1.000 km2 with a grid size of down to few meters. One of our goals within the project ProPolis is to design and test the practical implementation of PALM-4U in standard and innovative application fields which include thermal comfort (indices like PT, PET, UTCI), cold air balance (source areas, reach and others), local wind comfort (indices derived from medium winds and gusts) as well as dispersion of pollutants.

In close cooperation with our practice partners, we explore the potential of PALM-4U to support the urban planning processes in each specific application setting. Additionally, with development of the fit for purpose graphic user interface, manuals and trainings we aim to enable practitioners to apply the model for their individual planning questions and adaptation measures.

In our presentation, we will show an application case of PALM-4U in a major German city. We will investigate the effect of a planned development area on the local climate and the impact of different climate change adaptation measures (such as extensive vs. intensive green roofs). The comparative simulations of the current state and planning scenarios with integrated green and blue infrastructure should provide arguments for the municipal decision making in consideration of climate change aspects in a densely built-up environment, e.g. urban heat stress.
Interpolation of Regionalized Intensity Duration Frequency (IDF) Estimates based on the observed precipitation data of Baden Wurttemberg (BW), Germany
Authors: Amin Bushra , Bárdossy András
Published: March 2021

This study is intended to carry out the spatial mapping with ordinary Kriging (OK) of regional point Intensity Duration Frequency (IDF) estimates for the sake of approximation and visualization at ungauged location. Precipitation IDF estimates that offer us valuable information about the frequency of occurrence of extreme events corresponding to different durations and intensities are derived through the application of robust and efficient regional frequency analysis (RFA) based on L-moment algorithm. IDF curves for Baden Wrttemberg (BW) are obtained from the long historical record of daily and hourly annual maximum precipitation series (AMS) provided by German Weather Service from 1960-2020 and 1949-2020 respectively under the assumption of stationarity. One of the widely used Gumbel (type 1)  distribution is applied for IDF analysis because of its suitability for modeling maxima. The uncertainty in IDF curves is determined by the bootstrap method and are revealed in the form of the prediction and confidence interval for each specific time duration on graph. Five metrics such as root mean square error (RMSE), coefficient of determination (R²), mean square error (MSE), Akaike information criteria (AIC) and Bayesian information criteria (BIC) are used to assess the performance of the employed IDF equation. The coefficients of 3-parameteric non-linear IDF equation is determined for various recurrence interval by means of Levenberg–Marquardt algorithm (LMA), also referred to as damped least square (DLS) method. The estimated coefficients vary from location to location but are insensitive to duration. After successfully determining the IDF parameters for the same return period, parametric contour or isopluvial maps can be generated using OK as an interpolation tool with the intention to provide estimates at ungauged locations. These estimated regional coefficients of IDF curve are then fed to the empirical intensity frequency equation that may serve to estimate rainfall intensity for design purposes for all ungauged sites. The outcomes of this research contribute to the construction of IDF-based design criteria for water projects in ungauged sites located anywhere in the state of BW.

In conclusion, we conducted IDF analysis for the entire state of BW as it is considered to be more demanding due to the increased impact of climate change on the intensification of hydrological cycle as well as the expansion of urban areas rendering watershed less penetrable to rainfall and run-off, the better understanding of spatial heterogeneity of intense rainfall patterns for the proposed domain.
Characterization of soil infiltration by stable water isotopes and an improved lumped-parameter model approach
Authors: Imig Anne , Shajari Fatemeh , Einsiedl Florian , Rein Arno
Published: March 2021

In order identify the impact of chemicals on water quality and related risks, an understanding of soil infiltration processes in the unsaturated zone is required. In this work, two lysimeters installed at a test field south of Munich, Germany, were investigated. Maize was cultivated at the test field, and lysimeter soil cores are characterized by sandy gravels (lysimeter 1) and sandy-clayey silt (lysimeter 2). For three years, stable water isotopes in precipitation and seepage water were measured in 1-2 week intervals. Observations were interpreted by modeling in order to identify mean transit times of water and dispersion properties. A lumped-parameter model (LPM) implementing an analytical solution was applied. By subdividing the whole observation period into seasonal and vegetative periods with quasi steady-state flow the LPM was improved. Mean transit time of water, dispersion parameters and the contribution of preferential flow paths for all sub-periods with constant conditions were estimated. The improved LPM allows to mimic transient flow conditions and was able to describe the stable water isotope observations more accurately. Hence, the improved LPM approach could reduce model uncertainties as compared to the consideration of steady-state flow. In order to validate the findings from the improved LPM and enhance process understanding, unsaturated flow was also modeled numerically using Hydrus 1D. Soil hydraulic parameters were deducted from laboratory experiments and further adjusted by inverse modeling. Findings from applying the improved LPM could generally be confirmed by numerical modeling. Advantages of the improved LPM over numerical models include the need of a lower number of fitting parameters, which are often associated with higher uncertainties and required efforts concerning model input data. Combing the measurement of stable water isotopes in precipitation and seepage water with the improved LPM revealed a promising approach that could also be applied to support decision making, such as for agricultural practices that aim at minimizing chemical impacts to soil and groundwater quality. Investigations are currently continued for improving simulations by the consideration of mobile and immobile water and root water uptake.
A Source to Sink Approach to the North Sea Fan Pleistocene Glacial Sediments
Authors: Machado Garcia Aurora , Midtkandal Ivar , Bellwald Benjamin , Anell Ingrid Margareta
Published: March 2021

Trough mouth fans are large depocentres forming the ultimate sinks in glacial source-to-sink systems. Their architecture, sedimentological aspects (origin and processes) and their role as paleoclimatic archives are essential components in improving our understanding of Pleistocene and ongoing climate changes. For many years, these depocentres were thought to be dominated by debris flows accumulated in front of ice streams located at the shelf break. However, recent studies have shown that meltwater plays a major role in bringing sediment to the most distal parts of these fans, especially in lower latitudes. The North Sea Trough Mouth Fan encompasses ~110,000 km2 with water depths of up to 3500 m. It has received sediments throughout the Quaternary, with increased sedimentation rates in the last 1.1 Ma when the Norwegian Channel Ice Stream was active. Recent insight of the fan shows that meltwater turbidites play a major role in sediment delivery to the continental slope and deep-sea basin. The results could entail distinct morphologies for mid-latitude and high-latitude fans. As a result of glacial erosion and the absence of clear imprints of ice sheets on the paleo-shelves, studying trough mouth fan deposits becomes paramount in understanding glacial-interglacial cycles. This project will assess the source-to-sink parameters of the last glaciation (Weichselian) at the North Sea Fan, elucidating the dominant marine and terrestrial processes that led to the studied sedimentary sequences. High-resolution 2D and 3D seismic data, core, volumetric and numerical modeling data will be assimilated to establish a source-to-sink model for the target interval. These results will contribute to the knowledge of how glaciations affect surface mass redistribution, directly affecting the landscape dynamics and sediment routing from Fennoscandia via the North Sea to the slopes and deep basin. Sediment production will be evaluated, assessing whether it increases during the glaciation or if observed higher sedimentation rates are a result of enhanced sediment transport. This project is a part of the Marie Sklodowska-Curie Innovative Training Networks “S2S – Future: Signal propagation in source to sink for the future of the Earth resources and energy” and will further advance how trough mouth flans are highly dynamic areas where sediment transport, dispersal, remobilization and deposition take place, and serve as excellent proxies to the dynamics of glacial pulses in the hinterland.
Denudation response of the Mediterranean Alpine Ranges to the Quaternary glacial cycles
Authors: Blard Pierre-Henri , Molliex Stéphane , Mariotti Apolline , Charreau Julien , Jouet Gwenaël , Toucanne Samuel , Jorry Stephan
Published: March 2021

It is important to better understand how climatic fluctuations modified denudation, in particular during the large amplitude glacial cycles of the Quaternary, not only because denudation is thought to be a long-term climate pacer, but also because available denudation records are contradictory and sometimes underconstrained. To make progress on this question, we present here a compilation of 10Be-derived denudation rates from 6 boreholes and cores drilled in offshore sediments from two alpine massifs of the Mediterranean Sea: Southern Alps (Var River) and Corsica (Golo River). This original dataset of 60 10Be samples from well-dated sedimentary archives documents at high resolution (1 kyr in some sections) the denudation variability over the last 3 million years of the alpine reliefs, with a special focus on the last five 100 kyr glacial cycles. Our new record brings two main results:

1) At the million years timescale, the appearance of the Quaternary glaciations at the Plio-Pleistocene transition (2.6 Ma) had a negligible impact on the mean 10Be-derived denudation rates of Mediterranean Alpine reliefs. This observation is in good agreement with other 10Be-denudation rates records from Asia (Tianshan and Himalaya) that report a limited impact of the Pleistocene climatic transition (Puchol et al., 2017; Charreau et al., 2020; Lenard et al., 2020), but at odds with other regions of the American Cordilleras, where tectonic may have played a role (Stock et al., 2004; Granger and Schaller, 2014).

2) At the glacial-interglacial cycles timescale, our high resolution 10Be data over the last 500 kys reveal that glacial maxima enhanced denudation compared to interglacial periods. However, this impact is variable in space and time, different denudation responses being observed between Southern Alps and Corsica. This contrasted behavior appears to be controlled by the velocity of paleoglaciers. Glacier flow being determined by the combined impact of paleoclimate and basin reliefs, this mechanism is responsible for a non-linear response of denudation to glacier fluctuations. This may explain why glaciations had regionally variable impacts on denudation (Mariotti et al., 2021).

References

Charreau, J. et al. (2020) Basin Research. doi: 10.1111/bre.12511; Granger, D. E. and Schaller, M. (2014) Elements, doi: 10.2113/gselements.10.5.369; Lenard, S. J. P. et al. (2020) Nature Geoscience, doi: 10.1038/s41561-020-0585-2; Mariotti, A. et al. (2021) Nature Geoscience, doi: 10.1038/s41561-020-00672-2; Puchol, N. et al. (2017) Bulletin of the Geological Society of America, doi: 10.1130/B31475.1; Stock, G. M., et al. (2004) Geology, doi: 10.1130/G20197.1.
Depositional environments in the northern Barents Sea, from the last glacial to the present — preliminary results
Authors: Trælvik Eilertsen Vårin , Tom Arne Rydningen , Forwick Matthias , Winsborrow Monica , Laberg Jan Sverre
Published: March 2021

The Eurasian Ice Sheet Complex was the world’s third largest ice mass during the last glacial maximum (LGM), and included the British, Fennoscandian and Svalbard–Barents Sea ice sheets. Of these three, the mostly marine-based Svalbard-Barents Sea Ice Sheet (SBIS) is the least well constrained in terms of ice sheet dynamics and deglacial retreat patterns. Improving the understanding of the behavior and decay of this marine paleo-ice sheet can provide knowledge that is relevant to understanding the future evolution of the marine terminating ice margins in Greenland and Antarctica, which are today undergoing rapid retreat and thinning.

We present high-resolution TOPAS sub-bottom profiler data and multi-proxy analyses of four sediment gravity cores (1.15 to 5.05 m long) retrieved from water depths of c. 250-550 m in a trough south of Kvitøya, NW Barents Sea. The data were collected during the Nansen Legacy (https:/arvenetternansen.com/) Paleo-cruise in 2018, with the aim of reconstructing the patterns and timing of deglaciation of the SBIS and postglacial environmental changes in the northern Barents Sea. The data show a succession of up to 10 m high and 400 m wide ridges, interpreted to be recessional push-moraines, representing small still-stands or re-advances of the ice front during its retreat in southwesterly direction. An up to 40 m high and 20 km long sedimentary wedge in the central and western part of the study area buries some of these moraines. This wedge is interpreted to be a grounding zone wedge representing a major still-stand or re-advance during the deglaciation.

The gravity cores are located distal to, on the distal slope and on top of the grounding zone wedge. A muddy diamict defines the lowermost unit in each core. It is interpreted to be primarily subglacial till. This till is covered by laminated mud, interpreted to represent sedimentation from meltwater plumes that emanated from the nearby ice margin. Massive marine mud containing scattered clasts (the clasts are interpreted to be ice rafted debris) define the uppermost unit in all cores. This is suggested to represent deposition from suspension settling and ice rafting in a glacier-distal environment at the end of the last glacial, as well as during modern conditions.

Radiocarbon dates (submitted for dating) will provide a minimum age for the formation of the grounding zone wedge and the recessional moraines in front of it. This will improve the chronology on the deglacial events forming these deposits and landforms. Together with detailed multi-proxy analyses of the sedimentary units, this will also provide new knowledge about the development from glacial conditions to a glacier-proximal and –distal, and an open marine environment from the last glacial to the present.
The influence of different oxygen regimes on metabolism and behavior of a soft shell clam Mya arenaria
Authors: Ouillon Natascha , Forster Stefan , Jarret Abigail , Sokolov Eugene , Sokolova Inna
Published: March 2021

Hypoxia is widely distributed in coastal benthic habitats and is driven by warming, nutrient pollution and the diurnal cycles of photosynthesis and respiration. Benthic sessile species, such as the soft shell clam Mya arenaria, are commonly exposed to oxygen fluctuations in their habitats which might negatively impact the performance and metabolism of clams. To determine the effects of different oxygen regime on metabolism and behavior of M. arenaria, we exposed the clams for 21 days to chronic (constant) hypoxia at 20% of air saturation, fluctuating (cyclic) hypoxia (~10-50% of air saturation) and normoxia (100% of air saturation). To mimic conditions occurring in coastal hypoxic zones, CO2 and pH levels varied with the oxygen. We assessed the digging performance, bioirrigation capacity and bioenergetics of the clams. Acclimation to constant or cyclic hypoxia did not affect the oxygen consumption of the clams, but the oxygen consumption rates declined at low ambient oxygen concentrations regardless of the acclimation to different oxygen regimes. Clams acclimated to constant hypoxia mainly used lipids, whereas clams acclimated to cyclic hypoxia used carbohydrates as energy fuel. Clams acclimated to constant or cyclic hypoxia dug slower compared to the clams acclimated to normoxia. Furthermore, bioirrigation capacity decreased in clams acclimated to constant hypoxia. Our results indicate that constant and cyclic hypoxia impair bioturbation and bioirrigation capacity of clams which has implications for their ecological function as ecosystem engineers in benthic soft bottom habitats. 
The impact of spatially varying wetland source signatures on the atmospheric variability of dD-CH4
Authors: Stell Angharad , Douglas Peter , Rigby Matthew , Ganesan Anita
Published: March 2021

We present the first spatially varying map of the δD-CH4 signature of wetland methane emissions and model its impact on atmospheric δD-CH4. The δD-CH4 signature map is derived by relating the δD-H2O of precipitation to the measured δD-CH4 of methane wetland emissions at a variety of wetland types and locations. Since the δD-H2O of precipitation is highly latitude-dependent, including this spatial variation has the potential to have a large impact on the distribution of δD-CH4 observed in the atmosphere. This latitude-dependence means that wetland emissions at different latitudes can have very different impacts on atmospheric δD-CH4, which could provide a useful way to constrain the location of wetland methane emissions in future inverse modelling studies. Here, we assess the implications for model studies on the differences that arise by treating δD-CH4 wetland source signatures as globally uniform rather than accounting for the large spatial variation. We also assess the potential for δD-CH4 to provide an independent constraint on wetland emissions over the more abundant and widely measured δ13C-CH4.
Dimensioning of riparian buffer zones in agricultural catchments at national level
Authors: Uuemaa Evelyn , Kull Ain , Mõisja Kiira , Nurm Hanna-Ingrid , Kmoch Alexander
Published: March 2021

Intensive agricultural production interferes with natural cycles of nutrients (mostly nitrogen and phosphorus) and may lead to water quality degradation due to excessive nutrient loadings. To mitigate this effect at the landscape level establishment of buffering vegetated strips is an efficient measure.

Recommending optimal widths for riparian buffer zones to reduce the agricultural runoff is still a challenging task, in particular when considering the spatial variability of the landscape. Empirical-based approaches include assessment of terrain, soil types, land use and vegetation, and are often realised in computationally expensive hydrological simulation. However, trade-offs have to be made between spatial resolution and areal extent. Another elegant empirical-based approach are nomographs, where via triangulation of a specific slope length, terrain slope and soil type recommended buffer width can be easily calculated. Mander and Kuusemets (1998) already developed such a nomograph for Estonian catchments in 1998, yet, a computational use case has not been explored.

We implemented the nomograph as a GIS algorithm in Python/QGIS to retrieve the recommended buffer width at national level. We synthesized a specific slope length via a weighted average of flow length, local flow accumulation and LS factor, and then use the specific slope length, slope derived from 5 m spatial resolution DEM and soil texture classes as inputs for the algorithm. We applied this algorithm and calculated recommendable buffer strip widths for the whole of country of Estonia, over an area of approx. 43,000 km2. We evaluated the uncertainty of the results as well the algorithm’s sensitivity to input weights.

The developed algorithm is applicable in any region with relevant adjustments to local soil types. The result directly informs policy making by being able to more specifically decide and explain variations of buffer zone widths along water bodies.
Using the measured Particle Size Distribution to assess the wind-induced bias of catching-type raingauges.
Authors: Stagnaro Mattia , Cauteruccio Arianna , Lanza Luca Giovanni , Chan Pak-Wai
Published: March 2021

Wind-induced biases that affect catching-type precipitation gauges have been largely studied in the literature and dedicated experimental campaigns in the field were carried out to quantify this bias for both liquid and solid precipitation (including the recent WMO intercomparison on solid precipitation – SPICE). Experimental results show a large variability of the Collection Efficiency (CE) curves that depend on the precipitation type, intensity and the Particle Size Distribution (PSD) (see e.g. Colli et al. 2020). This was confirmed by recent studies using Computational Fluid Dynamic simulations to assess the airflow pattern around the gauge body and particle tracking models to simulate the particle trajectories when approaching the collector and calculating the Catch Ratio (CR) associated with various drop size - wind speed combinations (see e.g. Colli et al 2016, Cauteruccio and Lanza 2020).

In the present study, the CR values derived from the work of Cauteruccio and Lanza (2020) for a catching-type cylindrical gauge as a function of the drop size were fitted with an inverse second-order polynomial. The parameters of such curves were themselves expressed as a function of the wind speed. This formulation was adopted to calculate the CE of a catching-type cylindrical gauge based on contemporary wind and PSD measurements. These were obtained at the field test site of the Hong Kong International Airport using six co-located anemometers and a two-dimensional video disdrometer (2DVD), at one-minute resolution. The obtained CE was used to correct the rainfall intensity measured by three catching-type cylindrical gauges, located at the same site, and was compared with the ratio between the raw data measured by the three cylindrical gauges and the 2DVD rainfall intensity measurements. Results show the improvement due to the correction and suggest that the 2DVD is subject to some wind-induced bias as well.

References:

Cauteruccio, A. and L. G. Lanza, 2020. Parameterization of the Collection Efficiency of a Cylindrical Catching-Type Rain Gauge Based on Rainfall Intensity. Water, 12(12), 3431.

Colli, M., Lanza, L.G., Rasmussen, R. and J.M., Thériault, 2016. The Collection Efficiency of Shielded and Unshielded Precipitation Gauges. Part II: Modeling Particle Trajectories. Journal of Hydrometeorology, 17(1), 245-255.

Colli, M., Stagnaro, M., Lanza, L.G., Rasmussen, R. and J.M., Thériault, 2020. Adjustments for Wind-Induced Undercatch in Snowfall Measurements based on Precipitation Intensity. Journal of Hydrometeorology, 21, 1039-1050.
Vulnerability mapping to Covid-19 of the metropolitan area in central Tuscany 
Authors: Pileggi Tiziana , Cioli Simona , Caporali Enrica
Published: March 2021

The COVID-19 pandemic has made urgent the need to improve the resilience of urban system from the effects of different hazards (natural, biological, technological and slow-onset climate change-related) through a multi hazard and multi sector approach that allows a more efficient use of resources and a holistic view of risk, including the interconnectedness across multiple hazards. According to Bangkok Principles for the implementation of the health aspects of the Sendai Framework for Disaster Risk Reduction 2015-2030, systematic integration of health aspects in Disaster Risk Reduction strategies is undelayable.

Building urban resilience means identifying vulnerabilities rapidly and adopting adequate actions to anticipate, resist and recover with the least amount of damage in front hazards impacts.

In this context, a synthetic index to measure vulnerability to COVID-19 is developed, by integrating different levels of information related to demographic characteristics, health profiles and access to resources, in order to identify any situations of fragility and predisposition to the spread of the epidemic, thus constituting a support element for the adoption of an efficient intervention strategy and for the management of any new epidemic waves. The integrated and multi-disciplinary approach that has been chosen allows, indeed, to take into account the complexity and multi-disciplinary nature of the concept of vulnerability. The following information are  analysed: demographic characteristics (population density, age, residence in welfare and prisons facilities); health profiles (presence of previous chronic diseases, such as cancer, diabetes, heart disease, lung disease, and particular lifestyles, such as smoking, alcohol consumption, poor diet) and characteristics of the local health infrastructure (number of beds, ratio of population to family doctor, number of health facilities in the area). To construct the vulnerability index, a Geographical Information System is setted up, through which the data are analysed, processed through normalisation, given the different availability and heterogeneity of the information, and combined. The resulting spatial data infrastructure allows us to rapidly identify situations of adversities and possible infrastructural deficiencies. 

The first prototypical result provides the implementation of an index of vulnerability to COVID19 and the related information support system, related to the metropolitan area in central Tuscany, in which there is a good availability of open data at different levels of geographical details and for which research on vulnerability to various types of risk is carried out and in progress.
Anisotropic fragmentation of shrinking thin layers on a substrate
Authors: Szatmári Roland , Kun Ferenc
Published: March 2021

Layers of dense pastes, colloids attached to a substrate often undergo sequential cracking due to shrinkage stresses caused by desiccation. From the spectacular crack patterns of dried out lake beds through the polygonal ground patterns of permafrost regions to the formation of columnar joints in cooling volcanic lava, shrinkage induced cracking is responsible for a large variety of complex crack structures in nature. Under laboratory conditions this phenomenon is usually investigated by desiccating thin layers of dense colloidal suspensions in a container, which typically leads to polygonal crack patterns with a high degree of isotropy.

It is of great interest how to control the structure of shrinkage induced two-dimensional crack patterns also due to its high importance for technological applications. Recently, it has been demonstrated experimentally for dense calcium carbonate and magnesium carbonate hydroxide pastes that applying mechanical excitation by means of vibration or flow of the paste the emerging desiccation crack pattern remembers the direction of excitation, i.e. main cracks get aligned and their orientation can be tuned by the direction of mechanical excitation.

In order to understand the mechanism of this memory effect, we investigate a fragmentation process of a brittle, cylindrical sample, where the driving force of the cracking coming from a continous shrinkage, which sooner or later destroys the cohesive forces between the structure’s building blocks. Our study is based on a two dimensional discrete element model, where the material is discretised via a special form of the Voronoi-tesselation, with the so-called randomised vector lattice which allows to fine-tune the initial disorder of the system. We assume that the initial mechanical vibration imprints plastic deformation into the paste, which is captured in the model by assuming that the local cohesive strength of the layer has a directional dependence: the layer is stronger along the direction of vibration. We demonstrate that - based on this simple assumption - the model well reproduces the qualitative features of the anisotropic crack patterns observed in experiments. Gradually increasing the degree of anisotropy the system exhibits a crossover from an isotropic cellular structure to an anisotropic one.
Sargassum Monitoring –  Sargassum Detection in the Tropical Atlantic for Operational and Seasonal Planning 
Authors: Sutton Marion , Stum Jacques , Dufau Claire
Published: March 2021

Unprecedented massive landings of Sargassum are regularly registered since 2011 along the shorelines of the Caribbean Sea, Gulf of Mexico and West Africa. Algae arrive from the open sea as large rafts (tenths of km) after drifting over long distances in the Central Atlantic NERR, and accumulating in consolidation areas in the Brazil retroflexion current and probably the Gulf of Guinea. Washing-ashore has tremendous negative impacts on local populations, coastal marine ecosystems and the economy sector, especially tourism and fisheries that are severely affected.

CLS has been developing a Sargassum algae monitoring and operational forecasting service (SAMTool) based on optical satellite sensors technologies and ocean-surface drift modelling. This service intends to provide support on decision-making to governmental and non-governmental agencies involved in monitoring, evaluating, mitigating or tackling the recurrent Sargassum environmental issue: Meteorological Offices, Coast Guards, Navies, Port Authorities, Marine Park managers, scientists, NGOs, Touristic and Fisheries organisations, etc.

With the support of ESA, a pool of nearly 40 end-users from several Caribbean islands and neighboring countries: Mexico, Belize, Aruba, Curacao, Bonaire, French Antilles, Barbados, Jamaica, Dominican Republic, Sint Maarten, Trinidad & Tobago, Antigua & Barbuda, were able to use the service from April 2019 to October 2020, and gave a general very positive feedback in terms of usefulness, operationality, and forecast quality of the  service.

In the frame of the H2020 e-shape project, CLS is testing the deployment of the service on a cloud infrastructure and exploring the DIAS capabilities to enhance the system and allow seasonal prediction. Further works are on-going to implement a new sargassum detection index algorithm to reduce false alarms and to explore the added-value of using SAR satellite data. The use of a cloud infrastructure in e-shape will allowed the computation of a reanalysis of sargassum detection at 300-m resolution  on Sentinel-3 data and will extent the computing capacity of the drift model to predict the Sargassum arrival months in advance.

The presentation will focus on the scientific and technical results of the seasonal approach developed in e-shape.