bluuebunny/crossref_metadata_2025 huggingface dataset:
Trace-element migration during crystal-plastic deformation in UHP rutile: dislocations in low-angle boundaries as high-diffusivity pathways.
Authors: Verberne Rick , van Schrojenstein Lantman Hugo , Reddy Steven , Alvaro Matteo , Wallis David , Fougerouse Denis , Langone Antonio , Scambelluri Marco , Saxey David , Rickard William
Published: March 2021

The trace-element composition of rutile is commonly used to constrain P-T-t conditions for a wide range of metamorphic systems. Recent studies have highlighted the importance of micro- and nanostructures in the redistribution of trace elements in rutile via high-diffusivity pathways and dislocation-impurity associations. In this contribution, we investigate the effect of crystal-plastic deformation of rutile on its composition by combining microstructural and petrological analyses with atom probe tomography. The studied sample is from an omphacite vein of the ultrahigh-pressure metamorphic Lago di Cignana unit, Western Alps, Italy. Zr-in-rutile thermometry and inclusions of quartz in rutile and of coesite in omphacite constrain rutile deformation to around the prograde HP-UHP boundary at 500–550 °C. Crystal-plastic deformation of a large rutile grain resulted in low-angle boundaries that generate a total misorientation of ~25°. Dislocations constituting the low-angle boundary are enriched in common (Fe, Zr) and uncommon trace elements (Ca). The Ca is interpreted to be derived from the grain exterior, suggesting diffusion of trace elements along the dislocation cores. The potential for dislocation microstructures to act as fast diffusion pathways must be evaluated when applying traditional geochemical analyses as compositional disturbances caused by the presence of dislocation might lead to erroneous interpretations.
Embracing the “I” in biogeomorphology - on the role of individuals in self-organised coastal landscapes    
Authors: Reijers Valérie
Published: March 2021

Biogeomorphic landscapes emerge through feedback interactions between geophysical processes and biota. Plants can stabilize the soil with their extensive root systems or modulate flows of wind and water with their aboveground canopy, promoting local sediment deposition. Different plant species have evolved different suites of traits that affect their landscape-modifying ability. Here, I will present our recent work on the interactions between individual-scale organization patterns and sediment capture for dune building grasses. Using a combination of field surveys, experiments, and simple numerical models, we demonstrate that different species exhibit different clonal expansion strategies, which determine their sediment capture efficiency. Additionally, even within the same species individuals can express different organizational patterns depending on sediment dynamics. Understanding how individual plants engineer their environment depending on prevailing geophysical conditions, and how these individual-scale interactions affect both plant and landscape dynamics, is crucial for unravelling the dynamics of complex biogeomorphic landscapes.
Effect of Gap Geometries on the Crack Initiation Stress of Synthetic Rock Material
Authors: Zengin Enes , Erguler Zeynal Abiddin
Published: March 2021

The cracking phenomenon of the brittle rock and rock-like materials (concrete, gypsum) have been widely researched. Such long-standing intensive research requirement is due to the fact that crack initiation, propagation and coalescence are some of the most important parameters for evaluating the rock failure behavior and strength properties. Especially defining the crack initiation stress is a fundamental part of crack propagation that leads to the rock material's final failure. However, due to the nature of rocks, they may have complex inherit structures containing various gaps and void with different sizes and numbers. Rocks mostly tend to have circular and ellipsoidal voids as a result of long and complex geological processes. Owing to this limitation, it is always hard to understand and assess the crack initiation stress comprehensively. Especially for a couple of decades, with the help of developing computer science and technology, numerical models were used on this subject. In this study, various two-dimensional numerical rock models created using Distinct Element Method (DEM) based Particle Flow Code (PFC) were used to understand the effect of different gap geometries over crack initiation stress values of rock materials under uniaxial loading conditions. A base numerical model was calibrated using laboratory test results belonging to basalt rocks. In order to calibrate the numerical model, uniaxial, conventional triaxial and in-direct tensile test results were used. A flat-jointed contact model was chosen to create bonded material during the calibration process. Seven different numerical models were used to investigate the gap geometry effect on crack initiation stress under uniaxial conditions. The base model has a circular gap with 5.40 mm diameter. The other models created to understand the effect of geometry on crack initiation stress have different ellipsoidal geometry depending on the initial circular gap, 1.5 (8.10 mm), 2.5 (13.50 mm) and 3.5 (18.20 mm) times the diameter in the vertical and horizontal direction, respectively. The results of numerical models reveal that the crack initiation stress value decreases with the increase of the gap's vertical length while the width of gaps remains constant. Based on numerical models' results, the crack initiation stress value decreases with the increase of the gap's vertical length while the diameter of gaps remains constant.
The influence of different roll erosion control products to the particle size distribution of the soil sediment eroded on artificial slopes
Authors: Kubínová Romana , Kavka Petr , Neumann Martin , Kubát Jan-František
Published: March 2021

In this contribution the particle size distributions of the soil sediment obtained from soil erosion experiments were analysed. All the tests were done on arable topsoil’s, separately the size distribution of the soil aggregates and individual soil particles were evaluated. Soil erosion was initiated under the controlled conditions. CTU Prague laboratory rainfall simulator and field laboratory in Jirkov were used for this research. The rainfall was artificially generated with use of a nozzle type rainfall simulator. The sediment transported due to the surface runoff and rill erosion was collected from the discharge of the inclined soil erosion plots (slopes 20 – 34°, slope length 4 m).
During each experiment, eight samples were collected. Four samples were collected during the first experimental rainfall. For the next ten days, the container was kept aside the rainfall. Afterwards, the raining with the rainfall simulator on plot (which now had different initial condition compared to the plot during the first experimental rainfall as the plot already contained erosion rills from the previous episode) has been resumed and another four samples were collected.
Experimental plots were vertically divided into two parts. On one part was an eel and on the second part were different types of rolled erosion control products (RECPs) – Enkamat 7010, and 7020, Biomac-C, coir fibres K700 and K400, jute, Macmat 8.1, mulch, hay, nonwoven, fortrac 3D and triangle. The influence of RECPs to the particle size distribution was investigated.
Laser diffraction has been selected as a method to determine particle size distribution and device Mastersizer 3000 was used. By the comparison of the particle size distribution, of more than five hundred samples, the different response to the soil erosion mechanism and the influence of external factors (slope of the experimental plot, initial condition and presence of RECPs) on the particle size distribution and soil aggregates content in eroded sediment were investigated. It has been found that both the particle size and aggregates size distribution of the eroded sediment changes considerably in time.
This research is funded by the TH02030428 - „Design of technical measures for slopes stabilization and soil erosion prevention” and by the International CTU grant SGS20/156/OHK1/3T/11.
Combining satellite and lidar measurements to investigate the sodium nightglow
Authors: Koch Julia , Bourassa Adam , Roth Chris , Lloyd Nicholas , Yuan Titus , She Chiao-Yao
Published: March 2021

Using a combination of different measurement techniques is important to understand the numerous processes happening in the MLT-region. One of those processes is the excitation of atomic sodium by reaction with ozone which leads to emission of electromagnetic radiation: a phenomenon called Airglow. Although the sodium excitation mechanism was already proposed in 1939 by Sidney Chapman and further investigation was done by a great number of scientists, there are still some key parameters that are not well-known today. One of those parameters is the branching ratio fA which determines the amount of sodium in the excited state. Exact knowledge of this value would offer the opportunity to use Na-nightglow measurements to determine sodium profiles in the MLT-region. In this study we used both, satellite measurements and ground-based Lidar measurements to help approach a more reliable branching ratio fA. By comparing measurements that were made by the two instruments OSIRIS on Odin (Satellite) and the Lidar of the Colorado State University (ground-based) we found a branching ratio fA of 0.064 +- 0.028.
High organic carbon input can accelerate global warming in rice paddy soil: increase unprotected soil organic carbon and CH4 emission
Authors: Song Hyeonji , Galgo Snowie , Canatoy Ronley , Chae Hogyeong , Kim Pil Joo
Published: March 2021

Soil C sequestration is widely regarded as the most reasonable way to mitigate global warming. Traditionally, a high amount of organic carbon (OC) input is strongly recommended to increase soil organic carbon (SOC) stocks in croplands. However, according to the whole-soil saturation theory, stable SOC (mineral-associated SOC) accumulation can be limited at a certain point, relying on silt and clay contents. Most studies based on the theory were conducted in aerobic soil condition. This relationship is still uncertain in a rice paddy that makes up 10.8% of total arable land and has an anaerobic soil environment. In this study, we investigated high OC addition can enhance soil C sequestration in a rice paddy. We added different OC levels (0.5, 2.0, 2.9, and 4.6 Mg C ha-1 yr-1) in rice paddy by incorporating cover crop biomass for nine years. SOC stock and soil saturation degree were determined. Unprotected, sand-associated, silt-associated, and clay-associated SOC were separated via density and size fractionation. Respired C losses (CO2-C and CH4-C) were monitored using the static closed chamber method. SOC stock did not linearly increase with higher amount of OC input. The carbon sequestration efficiency (i.e. the increase of SOC per unit of OC input) decreases with the amount OC added. Higher OM input significantly increased unprotected labile SOC content. Unprotected SOC (<1.85 g cm-3) exponentially increased as the SOC saturation degree was higher. On the other hand, stable SOC content did not exhibit a linear relationship with the SOC saturation degree. The higher OC addition level exponentially increased respired C loss. In particular, C loss via CH4 was more sensitive to high OC addition. We conclude that higher OC addition in rice paddy without consideration in terms of SOC stock saturation point can accelerate global warming by increasing labile SOC accumulation and CH4 emission.
A Lagrangian view of the transfer of Southern waters to the South Atlantic Ocean
Authors: Olivé Abelló Anna , Pelegrí Josep L. , Vallès-Casanova Ignasi
Published: March 2021

The Atlantic Meridional Overturning Circulation (AMOC), a key component of the Earth's climate system, is sustained through the northward transport of Southern Ocean waters to high latitudes. This returning limb of the AMOC consists largely of relatively cold waters entering from the Pacific Ocean through the Drake Passage, what is commonly referred to as cold-water route. Here, we explore the pathways and transit times of these Antarctic waters that are incorporated to the South Atlantic, with special attention to their recirculation in the subtropical gyre and their escape northward through the North Brazil Current. For this purpose, we use daily values of the climatological GLORYS12v1 velocity field, as obtained using data for 2002-2018 and track the trajectories with the help of the OceanParcels software. We trace the particles transiting through four sections in the Southern and South Atlantic Oceans: 64°W and 27°E, crossing entire Antarctic Circumpolar Current (ACC) through the Drake Passage and off South Africa, respectively; 32°S, from the African coast out to 5°S, sampling the eastern boundary current system; and 21°S, from the American coast out to 30°W, sampling the North Brazil Current.

Particles are released daily in the Drake Passage down to 1800 m during one full year, its spatial distribution and number being proportional to the transport crossing each vertical portion of the section. This represents an annual-mean of 116.3 Sv entering the Atlantic sector through the Drake Passage, split into 13.3 Sv for surface (Subantarctic Surface Water, SASW, and Subantarctic Mode Water, SAMW), 40.2 Sv for intermediate (Antarctic Surface Water, AASW, and Antarctic Intermediate Water, AAIW) and 62.8 Sv for deep (Upper Circumpolar Deep Water, UCDW) water masses. The particles are then tracked forward, with a one-day resolution, during 20 years. The simulation shows that about 83% of the SASW/SAMW transport follow the ACC past South Africa while the remaining 17% are incorporated to the subtropical gyre. Among the latter, only 13% veer northward and cross the 21°S section. Regarding the intermediate waters, AASW/AAIW, 93% of transport follows the ACC, and 7% join the subtropical gyre. Finally, for the UCDW transport, which remains part of ACC, about 97% follow eastward as the ACC and only 3% drift cross the 32°S section, and only 4% of the latter reach through the 21°S section. The median times for the Drake Passage water particles to get to the 27°E, 32°S and 21°S sections are: 1.7, 2.1 and 5.7 yr for the SASW/SAMW; 2.3, 5.3 and 6.5 yr for the AASW/AAIW; and 3.3, 6.0 and 11.7 yr for the UCDW, respectively. Long tails in the age distributions reflect a high degree of recirculation, being remarkable the high presence of mesoscale eddies around 32°S over Cape Basin.
The Operational Cloud Products for Sentinel-5 Precursor and Sentinel-4
Authors: Lutz Ronny , Molina García Víctor , Romahn Fabian , Argyrouli Athina , Loyola Diego
Published: March 2021

Sentinel-5 Precursor and Sentinel-4 are atmospheric Copernicus missions focused on trace gas, greenhouse gas, aerosol and cloud retrieval and operate in the UV/VIS/NIR/(SWIR) spectral region. A key ingredient for the retrieval of the aforementioned trace gases and greenhouse gases is a precise knowledge of the presence of clouds. On top of that, clouds are by themselves interesting to measure and monitor because of their contribution to the radiation budget, and hence, impact on climatological applications. In this contribution, we present the algorithms for retrieving the operational cloud products from TROPOMI onboard Sentinel-5 Precursor and the UVN spectrometer onboard Sentinel-4. These are called OCRA (Optical Cloud Recognition Algorithm) and ROCINN (Retrieval of Cloud Information using Neural Networks) and both have their heritage with GOME/ERS-2 and GOME-2 MetOp-A/B/C, where they have already been successfully implemented in an operational environment.

OCRA employs a broad band color space approach to determine a radiometric cloud fraction and ROCINN retrieves cloud top height, cloud optical thickness and cloud albedo from NIR measurements in and around the oxygen A-band, taking as a priori input the cloud fraction computed by OCRA.
The cloud parameters retrieved by ROCINN are provided for two different cloud models. One which treats clouds more realistically as layers of scattering water droplets (clouds-as-layers, CAL) and one which treats clouds as simple Lambertian reflectors (clouds-as-reflecting boundaries, CRB).
The current status of the algorithms is presented along with recent developments and improvements.
Extraction and methylation parameters of phospholipid fatty acid analysis and their effect on total yield and community structure
Authors: Wiesenberg Guido , Zosso Cyrill
Published: March 2021

Phospholipid fatty acids are membrane compounds of microbial cell walls and the structure of individual compounds is indicative for specific microbial groups. The extraction and analysis of phospholipid fatty acids in soils improved our understanding of factors driving microbial abundance and community composition. Despite the wide application of this method, important pitfalls persist which impede comparability of PLFA results between studies.

Here, we show that there was an effect of freeze-drying on the community composition. However, compared to the effect of using of old extraction solution (4 weeks) and two different methylation procedures, this effect seems negligible. Using old extraction solution, the overall yield of PLFA was 12% lower and and we observed significant differences in the relative abundances of functional microbial groups. But most importantly, base catalyzed methylation yielded 35% less PLFA compared to acid catalyzed methylation and the relative abundances of all microbial groups were completely different. Our results show that it is crucial to keep the analytical parameters constant to capture subtle treatment effects and that especially the use of different methylation methods prevents comparability between studies.
Using X-ray radiography to image rapid water infiltration into soil
Authors: Koestel John , Garbari Lorenzo , Iseskog Daniel
Published: March 2021

While the basic processes of water infiltration into soil are well understood, their details are difficult to quantify due to the opaque nature of soil. In this study, we investigated the potential and limitations of X-ray radiography to measure the water front progression in a narrow sample (15 × 15 × 1 cm) filled with dry soil under simulated rainfall of high intensity (53 mm/h). The temporal resolution of the acquired infiltration movies was 133 milliseconds. We evaluated three different kinds of soil samples. i) Bare samples filled with a 1:1 mixture of a sandy loam and peat. ii) The same soil-peat mixture, but cropped with Trifolium incarnatum, Trifolium repens, Lathyrus odoratus and Lupinus regalis, all of them plants that have been reported to induce water repellency; prior to the experiments, the plants were harvested and only the roots remained in place. iii) Sandy loam soil that had been incubated for four weeks in an outside garden plot. Due to time limitations of the project, the incubation period was in early spring, which meant that plant growth in the samples was negligible. All three sample types were replicated five times, resulting in 15 individual samples. We carried out the infiltration experiments in four-fold replications, from which it follows that we collected 60 individual infiltration movies. After each infiltration round, the samples were placed in a drying room to reset them to a similar initial moisture content. The experiments aimed at testing i) whether the infiltration patterns of the four consecutive infiltration runs conducted on each sample remained identical and ii) to document differences in infiltration patterns between bare, cropped and incubated samples. We found that increasing X-ray scattering with increasing soil water contents made it challenging to evaluate the image data quantitatively. Advantages of our setup are that X-ray captures the complete water content at a specific depth and that sample boxes with irregularly shaped walls can be used to prevent preferential flow along the walls. Preliminary analyses of the data showed that the infiltration fronts in the bare and the incubated samples were less uniform than the ones for the cropped samples. In contrast, the likelihood of observing the same infiltration pattern in all four consecutive infiltration runs was larger for the bare and the incubated samples. The latter fact may have been caused by the interaction with root exudates in the cropped samples that may have been redistributed or mineralized during the wetting-drying cycles. We conclude that the here presented setup has large potential to investigate unstable infiltration phenomena into soil after an image correction approach has been developed that removes X-ray scattering artifacts. Alternatively, scattering may be suppressed by using a collimator during image acquisition.
Near-surface Stokes drift in operational wave forecast
Authors: Hansen Carsten
Published: March 2021

Near-surface Stokes drift in operational wave forecast

We apply an operational model for the mean drift of small particles near and at the surface. The drift is a sum of the Stokes drift and the current. The Stokes drift is derived from a wave model and the current is calculated by means of a 3D hydrodynamic model.

In an operational wave model setup (based on WAVEWATCH-III version 7) a parametric tail is supplied as an extension to the prognostic wave spectrum. The parametrisation is based on the modelled spectra level and the first circular moment (the spectral spread) near the highest prognostic frequency, which is typically around 0.5 Hz in operational wave modelling.

New source terms formulations has been introcuced in wave modelling (e.g. WAVEWATCH-III with effect from 2019) that reproduces the spreading and spectral level well compared to many independent observations.

The Stokes drift is calculated at a discrete number of depths down to Z = 2/Ks, where Ks is a wave number scale estimated from the prognostic spectrum. The calculation is integrated in the wave model output.

The application is evaluated in complex weather situations between January 1 and January 6 2020 in the European North West Shelf region. A set of wave model setups are compared with a variation of values of the prognostic spectral cut-off.

It is demonstrated that a the near-surface drift profile is resolved well with an order of ten discrete depths, and the parametric tail extension requires a low computational time.
Detecting Deep Rock Weathering
Authors: Krone Laura , von Blanckenburg Friedhelm
Published: March 2021

The weathering front, the interface beneath Earth’s surface where unweathered bedrock is converted into weathered rock, is a zone where chemical disequilibrium results in some of the most intense mineralogical transformations. These are focused into a narrow zone; yet its depth is poorly known due to its inaccessible nature deep beneath the Earth’s surface. Studies in humid and temperate climate suggest a maximum depth of 20 m for the weathering front in granitoid rock (Hayes et al., 2020).

To explore whether this depth is unique to humid climate we drilled into fractured rock in the semi-arid climate zone of the Coastal Cordillera of Chile. We found deep weathering down to 76 m below the surface which represents one of the deepest weathering fronts ever found. To characterise and quantify rock weathering, we investigated mineralogical and geochemical transformations. Iron (Fe) oxidation and related porosity formation is the first weathering process taking place and hence an indicator for the onset of weathering (Buss et al., 2008). Elemental (τ) and bulk loss (chemical depletion fraction, CDF) calculated from the chemical composition reveal multiple zones with more intense weathering compared to bedrock, and where the specific surface area also increases due to formation of secondary solids. Fracturing and the related increase in macro-porosity thus induce these mineralogical and chemical transformations. Below 76 m, bedrock is devoid of weathering features. We suggest that tectonic pre-fracturing in this geologically active region provided transport pathways for oxygen to greater depths, inducing porosity by oxidation. This porosity was preserved throughout the weathering process, as secondary minerals that might fill pores were not formed due to the low fluid flow.

Hayes, N. R., Buss, H. L., Moore, O. W., Krám, P. and Pancost, R. D. (2020): Controls on granitic weathering fronts in contrasting climates. Chemical Geology, 535, 119450.

Buss, H.L., Sak, P. B., Webb, S. M. and Brantley, S. L. (2008): Weathering of the Rio Blanco quartz diorite, Luquillo Mountains, Puerto Rico: Coupling oxidation, dissolution, and fracturing. Geochimica et Cosmochimica Acta, 72 (18), 4488-4507.
The CO2 exchange of a small mountain lake as affected by the local thermo-topographically driven flow regime
Authors: Scholz Katharina , Battin Tom , Ejarque Elisabet , Hammerle Albin , Kainz Martin , Schelker Jakob , Wohlfahrt Georg
Published: March 2021

Lakes receive large amounts of carbon (C) from the surrounding catchment and, together with the connecting streams, play an important and active role in the global C cycle. The received C can either be lost through the outflow and eventually transported to the ocean, or transformed and stored in sediments or outgassed to the atmosphere. Globally, lakes are estimated to emit 0.3 – 0.64 Pg C m-2 in form of CO2 annually.  Although subalpine and alpine lakes were observed to be supersaturated with CO2, long-term measurements of lake-atmosphere CO2 exchange are sparse. Several methods to quantify water-atmosphere gas exchange exist, like chambers, eddy covariance (EC), mass-balance or gradient based methods including boundary layer models (BLM), each having its own advantages and disadvantages. However, quantifying CO2 exchange in aquatic ecosystems has often proved to be challenging. Here, both the BLM and the EC methods were used to estimate the air-water CO2 exchange of Lake Lunz, a small lake situated in complex mountainous topography of the Austrian Alps. The results indicated that the lake was a small source of CO2. Fluxes were affected by the thermo-topographic flow regime of the field site and its surroundings which drove the local wind pattern but also determined the local atmospheric CO2 concentration.  During most nights, a significant increase in atmospheric CO2 was observed which decreased the differential CO2 concentration at the air-water interface and therefore led to decreased nocturnal CO2 efflux. This diurnal pattern, however, was obscured in the EC measurements, because the method itself highly depends on the local wind regime. Because lakes are an integral part of mountain ranges which are characterized by catchments with complex topography, our findings are most likely of broader impact.
On the curious case of the recent decade, mid-spring precipitation deficit in central Europe 
Authors: Ionita-Scholz Monica , Nagavciuc Viorica , Kumar Rohini , Rakovec Oldrich
Published: March 2021

Central Europe has experienced a severe drought almost every April for the last 14 years consecutively, driven by record high temperatures, low flows, high evapotranspiration, and high soil moisture deficit. The dynamic of this recent and recurrent mid-spring dryness is not yet understood. Here we show that the period 2007 – 2020 was characterized by a reduction of ~50% of the usual April rainfall amount over large areas in central Europe. The precipitation deficit and the record high temperatures were triggered by a multiyear recurrent high-pressure system centered over the North Sea and northern Germany and a decline in the temperature gradient between the Arctic region and the mid-latitudes, which diverted the Atlantic storm tracks northward. From a long-term perspective, the precipitation, temperature, and soil moisture anomalies observed over the last 14 years have reached the highest amplitudes over the observational record. This study provides an in-depth analysis of the hydroclimate extremes in central Europe over the last 140 years and their atmospheric drivers, enabling us to increase our dynamical understating of long-term dry periods, which is vital to enhance forecasting and mitigation of such events.
Pushing the stability of a Differential Quantum Gravimeter below 1Eötvös/1µGal 
Authors: Janvier Camille , Lautier Jean , Merlet Sebastien , Landragin Arnaud , Pereira dos Santos Franck , Desruelle Bruno
Published: March 2021

One year after the first signals were obtained with the Differential Quantum Gravimeter (DQG) developed by muquans, we report on the new performances of the instrument. DQG is a unique instrument that combines the ability of simultaneously measuring the local gravity acceleration and its vertical gradient with an industry-grade geophysics-oriented design. Relying on a similar physical principle and same technologies developed for our absolute quantum gravimeters (AQG) [1], a single vertical laser beam simultaneously measures the vertical acceleration experienced by two sets of free-falling laser-cooled atoms from different heights. The vertical acceleration gives a direct access to g, and the difference of both measurements yields to vertical gravity gradient . [2,3]. 

Our demonstrator has been operational for a year and demonstrated best sensitivities of 53 E/√t, and 360nm/s²/√t, on the second floor of a university building. Long term stabilities below 1E and 10nm/s² levels have been obtained on 60 hours long measurements. After presenting the instrument and results, the talk will present the studies led to further improve the capabilities and performances. We will finally present ongoing works on mass detection experiments. Such experiments aim at assessing the accuracy of the instrument as well as its ability to detect and monitor underground density variations, opening new perspectives for applications in geodesy and hydrology.

This work has been supported by the DGA, the French Department of Defense, and the ANR GRADUS.

 

[1] V. Ménoret et al., "Gravity measurements below 10−9 g with a transportable absolute quantum gravimeter", Nature Scientific Reports, vol. 8, 12300 (2018)

[2] M. J. Snadden et al. “Measurement of the Earth's Gravity Gradient with an Atom Interferometer-Based Gravity Gradiometer” , Phys. Rev. Lett. 81, 971 (1998)

[3] R. Caldani et al. "Simultaneous accurate determination of both gravity and its vertical gradient", Phys. Rev. A 99, 033601 (2019)
Observation of wave propagation in ice using stereo imaging in the Sea of Okhostk
Authors: Alberello Alberto , Nose Takehiko , Kodaira Tsubasa , Nishizawa Keita , Nelli Filippo , Toyota Takenobu , Waseda Takuji
Published: March 2021

Sea ice seasonally covers the Sea of Okhotsk, a marginal Arctic basin nested between Russia and Japan, but its extent is predicted to decrease by 40% by 2050 leaving larger ice free areas over which waves can form. In the highly dynamical seasonal ice zone, i.e. where waves and ice interact, ice formation and breakup, and wave attenuation mutually affect each other via complex feedback mechanisms. To shed light into these interactions, wave measurements were conducted in the winter seasonal ice zone in the Southern Okhotsk Sea, North of Hokkaido, from onboard the P/V Soya using a stereo camera system. Data show that wave energy penetrates even in high ice concentration (>85%), where contemporary wave models predict complete attenuation of wind waves. Consistently with physical experiments and field observations of waves in the Arctic and Antarctic marginal ice zones, the measurements also show that the ice cover is more effective in attenuating short wave components and, consequently, the dominant wave period in ice is significantly increased compared to corresponding open ocean waves. The present data can inform calibration of wave models in the rapidly evolving seasonal ice zone in the Sea of Okhotsk.
The new Black Sea Reanalysis System within CMEMS
Authors: Lima Leonardo , Ciliberti Stefania Angela , Aydogdu Ali , Escudier Romain , Masina Simona , Azevedo Diana , Peneva Elisaveta , Causio Salvatore , Cipollone Andrea , Clementi Emanuela , Cretì Sergio , Stefanizzi Laura , Lecci Rita , Palermo Francesco , Coppini Giovanni , Pinardi Nadia , Palazov Atanas
Published: March 2021

Ocean reanalyses are becoming increasingly important to reconstruct and provide an overview of the ocean state from the past to the present-day. These products require advanced scientific methods and techniques to produce a more accurate ocean representation. In the scope of the Copernicus Marine Environment Monitoring Service (CMEMS), a new Black Sea (BS) reanalysis, BS-REA (BSE3R1 system), has been produced by using an advanced variational data assimilation method to combine the best available observations with a state-of-the-art ocean general circulation model. The hydrodynamical model is based on Nucleus for European Modeling of the Ocean (NEMO, v3.6), implemented for the BS domain with horizontal resolution of 1/27° x 1/36°, and 31 unevenly distributed vertical levels. NEMO is forced by atmospheric surface fluxes computed via bulk formulation and forced by ECMWF ERA5 atmospheric reanalysis product. At the surface, the model temperature is relaxed to daily objective analysis fields of sea surface temperature from CMEMS SST TAC. The exchange with Mediterranean Sea is simulated through relaxation of the temperature and salinity near Bosporus toward a monthly climatology computed from a high-resolution multi-year simulation, and the barotropic Bosporus Strait transport is corrected to balance the variations of the freshwater flux and the sea surface height measured by multi-satellite altimetry observations. A 3D-Var ocean data assimilation scheme (OceanVar) is used to assimilate sea level anomaly along-track observations from CMEMS SL TAC and available in situ vertical profiles of temperature and salinity from both SeaDataNet and CMEMS INS TAC products. Comparisons against the previous Black Sea reanalysis (BSE2R2 system) show important improvements for temperature and salinity, such that errors have significantly decreased (about 50%). Temperature fields present a continuous warming in the layer between 25-150 m, within which there is the presence of the Black Sea Cold Intermediate Layer (CIL). SST exhibits a positive bias and relatively higher root mean square error (RMSE) values are present in the summer season. Spatial maps of sea level anomaly reveal the largest RMSE close to the shelf areas, which are related to the mesoscale activity along the Rim current. The BS-REA catalogue includes daily and monthly means for 3D temperature, salinity, and currents and 2D sea surface height, bottom temperature, mixed layer fields, from Jan 1993 to Dec 2019.  The BSE3R1 system has produced very accurate estimates which makes it very suitable for assessing more realistic climate trends and indicators for important ocean properties.
Stratigraphic changes in shell size of a turritellid gastropod in the Holocene fossil record of the Po prodelta (Northern Adriatic Sea)
Authors: Scheidl Angela , Berensmeier Michaela , Nawrot Rafal , Albano Paolo G. , Tomašových Adam , Zuschin Martin
Published: March 2021

Over the last century, the northern Adriatic Sea has faced multiple ecological threats such as hypoxic events, eutrophication, pollution by heavy metals and plastics, and bottom trawling. These impacts were associated with major changes in the composition of benthic communities, particularly a decline in the abundance of Turritellinella tricarinata (= Turritella communis), the dominant gastropod species in the previously widespread Turritella-biocenosis of the northern Adriatic muddy bottoms. In this study, we reconstruct changes in abundance and size structure of T. tricarinata populations over the last 6000 years to better understand the drivers responsible for its recent decline and to provide a historical baseline for assessing potential recovery.

We studied sediment cores from two locations in the western Northern Adriatic Sea: (1) distal zones of Po prodelta based on a 3-meter-long gravity core collected at 31 m water depth comprising a condensed record of the last ~9,100 years, (2) proximal zones of Po prodelta based on five 1.5-meter-long piston cores taken at 21 m water depth in the Po prodelta, which capture the last 100-150 years. Core chronologies are based on radiocarbon-calibrated amino-acid racemization analyses of bivalve shells.

We analysed changes in the abundance and shell height of T. tricarinata in each increment of the cores. In total, 600 specimens have been measured. All stations show a similar pattern in shell abundance: a climax in the early 20th century and a strong decrease in the late 20th century.

The proximal records of Po prodelta show a negative correlation between abundance and median shell size, with larger size and lower abundance in the late the 20th century, a period characterized by recurrent severe hypoxic events. The 3-meter-long offshore core contains on average smaller specimens, but reflects a similar pattern: the number of larger specimens (>10 mm) and median shell sizes increase slightly towards the core top while total abundance declines. This trend towards larger shell size and lower abundance may reflect the complex effect of nutrient enrichment in a highly disturbed environment. During the last century Turritella communis might experience higher growth rates and lower predation but simultaneously reduced recruitment due to hypoxia and pollution.
A new approach of implementation of Wave Boundary Layer in OpenIFS
Authors: Makrygianni Nefeli , Pan Shunqi , Bidlot Jean , Bray Michaela
Published: March 2021

Despite of significant improvement in modelling of the atmosphere after years of research, the accuracy of predicting cyclone/typhoon waves still remains highly challenging. Evidence shows that the air-sea-waves interaction over the ocean surface can significantly impact on the coupled atmosphere-ocean systems, through momentum, mass, and energy exchanges. In particular, the momentum exchanges have been found to affect both the structure of the wave boundary layer and the sea state, through the wave dissipation and wave breaking. For many decades, studies suggested different parameterizations of the momentum fluxes, through drag coefficient (Cd) and the roughness length (z0). In recent years, research has been focused on the theoretical approaches of the momentum parameterization within the Wave Boundary Layer (WBL) in order to obtain the best Cd and z0 (Hara and Belcher 2002,2004; Moon et al. 2004; Du et al. 2017,2019). In this study, based on the works of Du et al. (2017, 2019), we introduce a new approach of the parameterization of the momentum flux using the roughness length. The potential of the scheme is analysed with extreme wind and wave events and the results are validated against buoy observations.
Novel application of mosses transplanted in bags as biointerceptors of airborne radioactive dusts after the Fukushima Dai-ichi Nuclear Power Station accident
Authors: Di Palma Anna , Adamo Paola , Dohi Terumi , Kenso Fujiwara , Hiroki Hagiwara , Iijima Kazuki
Published: March 2021

Nine years after the Fukushima Dai-ichi Nuclear Power Plant accident, in line with the strong efforts to devise ever more effective methods to monitor airborne radioactive dusts, in the present study we proposed for the first time the use of mosses transplanted in bags as biointerceptors of 134Cs and 137Cs in the evacuated zone of the Fukushima territory and according to a standardised protocol. The work aimed to investigate the ability of the moss transplants to accumulate radiocaesium and therefore to act as radiocaesium biointerceptors. To this purpose, the activity concentrations of radiocaesium were measured in moss bags filled with 3 widely studied moss species (Sphagnum palustre, Hypnum cupressiforme, Hypnum plumaeforme) and exposed for 3, 6 and 9 weeks at 5 residential sites within Fukushima area. The levels of radiocaesium found in moss bags were evaluated as function of different parameters (e.g. exposure time, site conditions, moss species). The moss bags were able to accumulate 137Cs in all exposure sites and periods, with Sphagnum palustre acting as the most performant moss species. The 137Cs activity concentrations (from 28 to 4700 Bq kg-1), could be explained by the Cs deposition levels and decontamination status of each exposure site, highlighting the sensitivity of the moss bags to discriminate among exposure sites according to their contamination level. Autoradiography and electron microscopy analysis of the distribution and the chemical composition of the particles entrapped by moss surfaces revealed a prevalence soil-derived radiocaesium. The linear dependency of Cs accumulation with the exposure time allowed a radiocaesium quantitative assessment by using location-specific (LF) and species-specific (SF) factors, with the latter susceptible to an “universal” applicability in future biomonitoring studies with the same experimental design.
Geomorphological numerical modelling of woody dams in CAESAR-Lisflood
Authors: Wolstenholme Josh , Skinner Christopher , Milan David , Parsons Daniel
Published: March 2021

Natural flood management (NFM) promotes the sustainable enhancement of natural fluvial processes to reduce flooding (SEPA, 2015; Wilkinson et al., 2019), and is increasingly popular for use by community groups, contractors and governments (Kay et al., 2019). Reintroduction of wood to a river channel is a popular form of NFM often achieved through seeding natural logjams, or with an emphasis on engineering through installing woody dams (WDs). WDs are currently installed or being installed in catchments in an effort to reduce flood risk, through hydrograph attenuation, increase biodiversity and improve geomorphic heterogeneity (Wenzel et al., 2014; Burgess-Gamble et al., 2017; Grabowski et al., 2019). A further objective is to emulate the effect of natural wood found in river channels by partially, or completely, blocking the channel to accelerate the recruitment of natural wood as part of the natural wood cycle (Addy & Wilkinson, 2016).

There is a growing body of evidence supporting the benefits of NFM, however, the hydrogeomorphic effects of WDs are less well understood (Dadson et al., 2017). There is little scientific underpinning concerning the long-term impact of these features upon hydrogeomorphology at reach and catchment-scales. Very few numerically based studies consider the influence of sediment transport on WDs, and how changes in local bed morphology influence their effectiveness. Most NFM research to date has focused upon modelling the effectiveness of local NFM measures in small catchments (<10 km2) (Dadson et al., 2017), with less work evident at larger spatial and temporal scales (Kay et al., 2019; Wilkinson et al., 2019).

There is a need for a verified tool that is able to represent WDs accounting for geomorphic processes and interactions between the dams and morphodynamics, different design specifications of dams, and changing efficacy due to geomorphic evolution. We present the new CAESAR-Lisflood (Coulthard et al., 2013) “Working with Natural Processes” toolkit, capable of representing WDs across a digital experimental environment. Global sensitivity testing was conducted using the Morris method (Morris, 1991) to assess the sensitivity of five aspects of the toolkit, and their potentially influences on geomorphology and flood risk reduction.
Phase relations and pre-eruptive conditions at low f(O2) in Pantelleria peralkaline rhyolites
Authors: Appiah Ernestina , Stabile Paola , Arzilli Fabio , Fabbrizio Alessandro , Carroll Michael Robert
Published: March 2021

The volcanic system of Pantelleria is an example of volcanism in a continental rift basin which over the years has attracted much researcher due to the different eruptive styles it exhibits, ranging from effusive to explosive. Investigating the cooling history as well as the magma transport dynamics of peralkaline rhyolitic magma is useful to understand the eruptive behaviour of the pantelleritic magma system.

The present work seeks to obtain information on the liquidus temperature of alkali feldspar in pantellerite from the Fastuca pumice fall unit (PAN13) under water-saturated conditions. Alkali feldspar is one of the most abundant crystalline phases in peralkaline rhyolitic melts as well as in evolved, alkali-rich magma compositions (e.g., trachyte, phonolite).

A series of water-saturated isobaric single-step cooling experiments were performed at reducing conditions (graphite filler rod, water P-medium, ~NNO-2) with final temperature range of 670 °C-880 °C and water pressure of 20-150 MPa. Phase equilibria show that clinopyroxene is the first liquidus phase always appearing by 750 °C, followed by alkali feldspar over the entire pressure and temperature (P-T) range investigated, with also the presence of aenigmatite crystallizing near the liquidus at P of 50 MPa. Providing experimental constraints on pre- and syn-eruptive magma crystallization is fundamental to better understand the eruptive dynamics of peralkaline rhyolitic magmas. This is important for volcanic hazard assessments of peralkaline rhyolitic magmatic systems.
Having a dry start into life - Drought impacts on child health in Malawi
Authors: Zimmer Anne , Plinke Charlotte , Lehmann-Uschner Katharina , Lange Stefan
Published: March 2021

Under- and malnutrition – particularly in the first years of life – can severely impact the physical and mental development of a child. This can have lasting consequences for the child’s future education, health and wellbeing outcomes. At the same time, climate change is expected to intensify the frequency and severity of droughts in many regions of the world, exacerbating concerns about food security and nutrition. Using repeated cross-sections of a large household survey in Malawi – a country where the majority of the population is engaged in smallholder subsistence agriculture and where virtually all agriculture is rainfed – we assess the impact of drought events on children’s health outcomes. We focus on stunting, a measure of chronic undernutrition and explore drought effects at different periods of a child’s development. To minimize concerns about recall error or reporting bias, we combine geo-referenced household data on child anthropometrics with biophysical data at high spatial resolution to measure drought exposure with the Standardized Precipitation Evapotranspiration Index (SPEI). The advantage of the SPEI over other drought indicators such as the SPI is that it accounts not only for precipitation but also other climate variables relevant to the water balance and thus agricultural productivity. We find that children exposed to a drought shock have a significantly lower height-for-age z-score (HAZ) and are at greater risk of being stunted. Furthermore, we explore which household characteristics and coping strategies might have helped in mitigating the drought impact on child health.