bluuebunny/crossref_metadata_2025 huggingface dataset:
High-Dimensional Granger Causality for Climatic Attribution
Authors: Margaritella Luca , Friedrich Marina , Smeekes Stephan
Published: March 2021

We use the framework of Granger-causality testing in high-dimensional vector autoregressive models (VARs) to disentangle and interpret the complex causal chains linking radiative forcings and global as well as hemispheric temperatures. By allowing for high dimensionality in the model we can enrich the information set with all relevant natural and anthropogenic forcing variables to obtain reliable causal relations. These variables have mostly been investigated in an aggregated form or in separate models in the previous literature. An additional advantage of our framework is that it allows to ignore the order of integration of the variables and to directly estimate the VAR in levels, therefore avoiding accumulating biases coming from unit-root and cointegration tests. This is of particular appeal for climate time series which are often argued to contain specific stochastic trends as well as yielding long memory. We are thus able to display the causal networks linking radiative forcings to global and hemispheric temperatures but also to causally connect radiative forcings among themselves, therefore allowing for a careful reconstruction of a timeline of causal effects among forcings. The robustness of our proposed procedure makes it an important tool for policy evaluation in tackling global climate change.
Early Permian syndepositional tectonics in the Orobic Basin, Southern Alps, Italy
Authors: Zanchi Andrea , Locchi Sofia , Zanchetta Stefano
Published: March 2021

The occurrence of synsedimentary tectonics during the beginning of the Permian has been largely documented all cross the present-day region of the central Southern Alps. Evidence of active faults has been generally established based on facies variations often associated to coarse-grained deposits, a characteristic feature of the Laghi Gemelli Group, which was deposited during the Early Permian. Nevertheless, poor attention has been devoted to the reconnaissance and description of the mesoscopic fault record developed during the deposition of the Lower Permian successions, except for a few works (Berra et al., 2011) describing local synsedimentary features such as liquefaction or slumping due to seismic shaking.

Working across the Orobic Alps, we identified several key areas where the occurrence of dewatering structures testify to the activity of synsedimenary faults together with sedimentary dikes, ball and pillars, and small slumps occurring along hundreds of mesoscopic faults showing meter-scale displacement along high-angle conjugate systems as well as domino-style faults, often accompanied by growth structures. These faults mainly affect the Pizzo del Diavolo Formation, which was deposited on top of the volcaniclastic succession of the Ca’ Bianca Volcanite.

According to our structural observations, these high-angle Andersonian normal faults are often associated with low-angle normal faults, which developed along the interface between the Permian cover and the Variscan basement (Bloom & Passchier, 1997; Zanchi et al., 2019). LANF systems are responsible for significant tectonic elision of the volcaniclastic lower successions and for diffuse hydrothermal circulation, resulting in widespread tourmaline deposition along the fault surfaces.

Our analyses point to the definition of tectonic setting characterized by pure extension dominated by ENE-WSW striking normal faults all across the central Southern Alps, which were later inverted during the Alpine shortening as high-angle reverse faults (Zanchetta et al., 2015). It is important to stress that in the considered area the strikes of the Early Permian structure are at odds with the Early Jurassic normal faults which generally show a N-S strike and were reactivated as strike-slip faults, pointing to an independent tectonic extensional event occurring 80 My after the Permian extension.

 

Berra F. et al. (2011). Sedimentary Geology, 235, 249-263

Blom, J. C., & Passchier, C. W. (1997). Geologische Rundschau, 86, 627-636.

Zanchetta et al. (2015). Lithosphere, 7, 662-681.

Zanchi A. et al. (2019). Italian Journal of Geosciences, 138, 184-201.
Individual Aerosol Droplet pH Measurement via a Ratio-metric Raman Method Using Aerosol Optical Tweezers: Evaluation of Thermodynamic and Activity Models
Authors: Li Meng , Su Hang , Zheng Guangjie , Kuhn Uwe , Li Guo , Ma Nan , Pöschl Ulrich , Cheng Yafang
Published: March 2021

Measuring pH in individual aerosol droplet is essential for understanding and estimating physicochemical processes within aerosol microenvironments. Recently, aerosol optical tweezers coupling with Raman spectroscopy have been applied to measure the pH of single trapped microdroplets by utilizing conjugate acid-base equilibrium to infer pH shifts. However, such measurements are easily affected by many factors such as variations in detecting volumes and laser intensities, making it hard to directly determine these acid and base concentrations through their respective peak areas. To overcome these problems and accurately measure the concentrations of SO42- and HSO4− within individual NaHSO4 microdroplets, in this study a ratio-metric spectroscopic method is developed based on the peak area ratio of ν(SO42−)/ν(OH) and ν(HSO4−)/ν(OH). Combined with the ion balance and ion activity coefficients, droplet pH is determined unambiguously. These experiment results were further used to evaluate the performance of activity models and thermodynamic models associated with aerosol pH, ion concentration and activity coefficient predictions. Pitzer, Simonson, and Clegg (PSC) model provides the best predictions of ion activity coefficients Extended Aerosol Inorganics Model vision IV (E-AIM IV) works well over a wide NaHSO4 concentration range (0.4-8.8 mol/kg), while ACCENT Pitzer model predictions have extremely good agreement with the experiment results in low NaHSO4 concentration condition (≤2.0 mol/kg). By contrast, ISORROPIA II shows relatively poor performance as compared with E-AIM IV.
The NASA Mass Change Designated Observable Study: Progress and Future Plans
Authors: Wiese David , Bienstock Bernard , Bearden David , Boening Carmen , Case Kelley , Chrone Jonathan , Horner Scott , Loomis Bryant , Luthcke Scott , Rodell Matthew , Sauber Jeanne , Tsaoussi Lucia , Webb Frank , Zlotnicki Victor
Published: March 2021

The 2017-2027 US National Academy of Sciences Decadal Survey for Earth Science and Applications from Space classified mass change as one of five designated observables having the highest priority in terms of Earth observations required to better understand the Earth system over the next decade.  In response to this designation, NASA initiated multi-center studies with an overarching goal of defining observing system architectures for each designated observable.  Here, we discuss the progress made and future plans for the Mass Change Designated Observable study. Progress includes the development of a Science and Applications Traceability Matrix (SATM), the definition of three different architectural classes that are responsive to the designated science objectives, and a framework to quantitatively link the performance of specific architectures to the SATM.  We will describe the Value Framework that has been developed to assess the value of potential architectures in terms of science return, cost, risk, and technical maturity.  Results highlight the recommendation of satellite-satellite-tracking for the MC observing system, and have identified high value variants as a single in-line pair, dual in-line pairs, and pendulum architectures, which are similar to architectures studied by potential international partners.  The current status of the study process, and future plans will be discussed.
On the use of the data- and physics-driven approaches for quasi-geostrophic double-gyre problem: application of Genetic Programming
Authors: Naghibi Elnaz , Naghibi Elnaz , Karabasov Sergey , Toropov Vassili , Gryazev Vasily
Published: March 2021

In this study, we investigate Genetic Programming as a data-driven approach to reconstruct eddy-resolved simulations of the double-gyre problem. Stemming from Genetic Algorithms, Genetic Programming is a method of symbolic regression which can be used to extract temporal or spatial functionalities from simulation snapshots.  The double-gyre circulation is simulated by a stratified quasi-geostrophic model which is solved using high-resolution CABARET scheme. The simulation results are compressed using proper orthogonal decomposition and the time variant coefficients of the reduced-order model are fed into a Genetic Programming code. Due to the multi-scale nature of double-gyre problem, we decompose the time signal into a meandering and a fluctuating component. We next explore the parameter space of objective functions in Genetic Programming to capture the two components separately. The data-driven predictions are cross-compared with original double-gyre signal in terms of statistical moments such as variance and auto-correlation function.

 
Revisiting the variation of the climate feedback parameter
Authors: Jiménez-de-la-Cuesta Diego
Published: March 2021

Observations and models indicate a varying radiative response of the Earth system to CO2 forcing. This variation introduces large uncertainties in the climate sensitivity estimates to increasing atmospheric CO2 concentration. This variation is represented as an additional feedback mechanism in energy-balance models, which depends on more than only the surface temperature change. Models and observations also indicate that a spatio-temporal pattern in the surface warming controls this additional contribution to the radiative response. However, several authors picture this effect as a feedback change in the atmosphere, reducing the role of the ocean's enthalpy-uptake variations. I use a widely-known linearised conceptual energy-balance model and its analytical solutions to find an explicit expression of the radiative response and its temporal evolution. This explicit expression provides another timescale in the Earth system, as the ocean-atmosphere coupling modulates the radiative response. Thus, to understand the variation of the climate feedback parameter, we need not only to know its relation to the spatio-temporal warming pattern but an improved picture of the ocean-atmosphere coupling that generates the pattern.
Large scale filed experiment on the landslide dam breaching
Authors: Huang Wei , Duan Wengang
Published: March 2021

Landslide dam breaching is the one of focus topics in the geophysical flows. The frequency of occurrence of landslide dam increases due to earthquake, climate change and mans activities in recent years. Once the dam breaks, it would trigger extreme flood downstream. A field experiment on landslide dam breach has been carried out on a small mountain river in Mianzhu, Sichuan Province, China from 23 November to 29 December, which aims to reveal impact of different diversion channel types on the dam breaching process as well as the resulting flood. The dam is of 4m high, 10~15m wide. the length of the dam crest is 5m, upstream downstream slopes of the dam are 1:2 and 1:5. Results show division channel can reduce the peak flood discharge obviously. The pilot vertical fall can trigger earlier back erosion and thus peak discharge appears earlier with smaller magnitude.
Long-term effect of organic amendments, mineral fertilizers and combinations thereof,  on plant yield, soil physic-chemical and microbiological properties
Authors: Kurzemann Felix , Plieger Ulrich , Probst Maraike , Spiegel Heide , Sandén Taru , Ros Margarita , Insam Heribert
Published: March 2021

The aim of this study was to investigate the influence of mineral fertilizer, different composts and combinations of compost/fertilizer as soil amendments on a loamy silt Cambisol after a 27-year field trial. Four different composts were used: urban organic waste (OWC), green waste (GC), farmyard manure (MC) and sewage sludge compost (SSC). In addition to plant growth, (physico-)chemical and microbiological changes in soil properties following amendment were analysed: total organic carbon (TOC) and nitrogen (N), soil pH, water holding capacity (WHC), basal respiration (BR), microbial biomass (Cmic) and microbial community composition. Fertilization promoted plant growth, when SSC or GC in addition with mineral fertilizer were applied compared to control. Concerning the (physico-) chemical properties only minor differences among the treatments were found. Phosphorus concentrations were three times higher in plots receiving SSC and SSC + N  than control or mineral N fertilizer alone and magnesium concentrations in plots treated with SSC were lower compared to soils treated with GC and MC, respectively. The bacterial community exceeded the fungal one in terms of both richness and diversity. Further, bacterial richness, diversity and community composition differed significantly among the treatments, whereas differences in fungal richness, diversity and composition seemed negligible. Our conclusion is that composts produced from various source materials serve as a valuable source for plant nutrients and can partially substitute mineral fertilizers, modulate soil microbial community and increase fertility. This way, they contribute to the mitigation of climate change.
Properties of H3+ and CH4 at mid and equatorial latitudes in the Jovian atmosphere, observed with JIRAM on Juno
Authors: Migliorini Alessandra , Dinelli Bianca M. , Moriconi Marialuisa , Altieri Francesca , Castagnoli Chiara , Mura Alessandro , Adriani Alberto , Sordini Roberto , Atreya Sushil , Tosi Federico , Bolton Scott , Piccioni Giuseppe , Grassi Davide , Moirano Alessandro , Noschese Raffaella , Cicchetti Andrea , Sindoni Giuseppe , Plainaki Christina , Olivieri Angelo
Published: March 2021

The NASA Juno spacecraft is studying Jupiter’s atmosphere in depth since August 2016. The Jupiter Infrared Auroral Mapper (JIRAM) experiment (Adriani et al. 2014), one of the scientific instruments on board Juno, is composed of two broad-band imagers and an infrared spectrometer, dedicated to the observation of the auroral and chemical composition of the Jupiter’s atmosphere. Images and spectral observations in limb view geometry have been acquired since orbit 17 (December 2018) onwards, providing a wealth of details of the atmosphere at mid to equatorial latitudes, with a spatial resolution of the order of hundreds of meters per pixel. CH4 and H3+ emissions around the 3-μm region show two well separated layers at 200 km and at about 500-600 km above the 1-bar level. The CH4 emission is quite unexpected and shows a maximum of emission close to the equator. In this work we present the distribution of CH4 and H3+ as observed at limb from December 2018 to September 2020 with the imaging subsystem of JIRAM. Their vertical distribution, obtained from simultaneous spectral measurements, is also shown. Temperature and volume mixing ratio (VMR) of the two species, retrieved using the spectral region between 3 and 4 μm (Dinelli et al. 2017, 2019) are discussed and compared with previous measurements.

Acknowledgments

The project JIRAM is funded by the Italian Space Agency.

 

References

Adriani A. Filacchione G., Di Iorio T., et al. (2014). JIRAM, the Jovian infrared Auroral mapper. Space Sci. Rev. 213, 393, https://doi.org/10.1007/s11214-014-0094-y.

Dinelli, B.M., et al. (2017), Preliminary Results from the JIRAM Auroral Observations taken during the first Juno orbit: 1 - Methodology and Analysis Applied to the Jovian Northern Polar Region, Geophys. Res. Lett., doi:10.1002/2017GL072929.

Dinelli B.M., Adriani A., Mura A., Altieri F., Migliorini A., Moriconi M.L., (2019). JUNO/JIRAM’s view of Jupiter’s H3+ emissions, Phil. Trans. R. Soc.
Seasonal variations in the transport and biogeochemical turnover of mainly dissolved organic nitrogen from the Lena Delta to the nearshore Laptev Sea
Authors: Sanders Tina , Fiencke Claudia , Fuchs Matthias , Haugk Charlotte , Mollenhauer Gesine , Ogneva Olga , Palmtag Juri , Strauss Jens , Tuerena Robyn , Dähnke Kirstin
Published: March 2021

Pan-arctic rivers transport a huge amount of nitrogen to the Arctic Ocean. The permafrost-affected soils around the Arctic Ocean containe a large reservoir of organic matter including carbon and nitrogen, which partly reach the river after permafrost thaw and erosion.

Our study aims to estimate the load of nitrogen supplied from terrestrial sources into the Arctic Ocean. Therefore, water, suspended particulate matter (SPM) and sediment samples were collected in the Lena Delta along a (~200 km) transect from the center of the Lena Delta to the open Laptev Sea in late winter (April) and in summer (August) 2019. In winter, 21 sample from 13 stations and in summer, 51 samples from 18 stations were taken. 9 of these sampling stations in the outer delta region were sampled in both seasons.

We measured organic and inorganic nitrogen and the 15N stable isotopes composition of all three sample types to determine sources, sinks and processes of nitrogen transformation during transport.

In winter, the nitrogen transported from the delta to the Laptev Sea were mainly dissolved organic nitrogen (DON) and nitrate, which occur in similar amounts. The load of nitrate increased slightly in the delta, while no changes to the isotope values of DON and nitrate were observe indicating a lack of biological activity in the winter season. However, lateral transport from soils was a likely source. In summer, nitrogen was mainly transported as DON and particulate nitrogen in the SPM fraction, including phytoplankton.

The nitrogen stable isotope values of the different nitrogen components ranges between 0.5 and 4.5 ‰, and were subsequently enriched from the soils via SPM/sediment and DON to nitrate. This indicates that nitrogen in the soils mainly originates from nitrogen fixation from the atmosphere. During transport and remineralisation, biogeochemical recycling via nitrification and assimilation by phytoplankton led to an isotopic enrichment in summer from organic to inorganic components. In the coastal waters of the Laptev Sea, the river waters are slowly mixed with marine nitrate containing waters from the Arctic Ocean, and a part of the riverine organic nitrogen is buried in the sediments.

We assume that the ongoing permafrost thawing and erosion will intensify and increase the transport of reactive nitrogen to coastal waters and will affect the biogeochemical cycling, e.g. the primary production.
Crustal velocity structure beneath the NW Dinarides from 1-D hypocenter-velocity inversion
Authors: Rajh Gregor , Stipčević Josip , Živčić Mladen , Herak Marijan , Gosar Andrej
Published: March 2021

The investigated area of the NW Dinarides is bordered by the Adriatic foreland, the Southern Alps, and the Pannonian basin at the NE corner of the Adriatic Sea. Its complex crustal structure is the result of interactions among different tectonic units. Despite numerous seismic studies taking place in this region, there still exists a need for a detailed, smaller scale study focusing mainly on the brittle part of the Earth's crust. Therefore, we decided to investigate the velocity structure of the crust using concepts of local earthquake tomography (LET) and minimum 1-D velocity model. Here, we present the results of the 1-D velocity modeling and the catalogue of the relocated seismicity. A minimum 1-D velocity model is computed by simultaneous inversion for hypocentral and velocity parameters together with seismic station corrections and represents the best fit to the observed arrival times.

We used 15,579 routinely picked P wave arrival times from 631 well-located earthquakes that occurred in Slovenia and in its immediate surroundings (mainly NW Croatia). Various initial 1-D velocity models, differing in velocity and layering, were used as input for velocity inversion in the VELEST program. We also varied several inversion parameters during the inversion runs. Most of the computed 1-D velocity models converged to a stable solution in the depth range between 0 and 25 km. We evaluated the inversion results using rigorous testing procedures and selected two best performing velocity models. Each of these models will be used independently as the initial model in the simultaneous hypocenter-velocity inversion for a 3-D velocity structure in LET. Based on the results of the 1-D velocity modeling, seismicity distribution, and tectonics, we divided the study area into three parts, redefined the earthquake-station geometry, and performed the inversion for each part separately. This way, we gained a better insight into the shallow velocity structure of each subregion and were able to demonstrate the differences among them.

Besides general structural implications and a potential to improve the results of LET, the new 1-D velocity models along with station corrections can also be used in fast routine earthquake location and to detect systematic travel time errors in seismological bulletins, as already shown by some studies using similar methods.
Multi-objective parameter optimization of the HYPE model using shuffled frog-leaping algorithm
Authors: Li Xinyu , Kasargodu Anebgailu Prajna , Dietrich Jörg
Published: March 2021

The calibration of hydrological models using bio-inspired meta-heuristic optimization techniques has been extensively tested to find the optimal parameters for hydrological models. Shuffled frog-leaping algorithm (SFLA) is a population-based cooperative search technique containing virtual interactive frogs distributed into multiple memeplexes. The frogs search locally in each memeplex and are periodically shuffled into new memeplexes to ensure global exploration. Though it is developed for discrete optimization, it can be used to solve multi-objective combinatorial optimization problems as well.

In this study, a hydrological catchment model, Hydrological Predictions for the Environment (HYPE) is calibrated for streamflow and nitrate concentration in the catchment using SFLA. HYPE is a semi-distributed watershed model that simulates runoff and other hydrological processes based on physical as well as conceptual laws. SFLA with 200 runtimes and 5 memeplexes containing 10 frogs each is used to calibrate 22 model parameters. It is compared with manual calibration and Differential Evolution Markov Chain (DEMC) method from the HYPE-tool. The preliminary results of the statistical performance measures for streamflow calibration show that SFLA has the fastest convergence speed and higher stability when compared with the DEMC method. NSE of 0.68 and PBIAS of 7.72 are recorded for the best run of SFLA during the calibration of streamflow. In comparison, the HYPE-tool DEMC produced the best NSE of 0.45 and a PBIAS of -3.37 while the manual calibration resulted in NSE of 0.64 and PBIAS of 2.01.
Temporal Variations in the Depth Estimate of Mass Density Changes at Mt Etna Volcano
Authors: King Thomas , Carbone Daniele , Greco Filippo
Published: March 2021

Continuous gravity measurements at Mt. Etna, Sicily demonstrate spatio-temporal variations that can be related to volcanic processes. Two iGrav superconducting gravimeters (SGs) were installed in 2014 and 2016 at Serra La Nave Astrophysical Observatory (SLN; 1,730 m elevation; ~6.5 km from the summit craters) and La Montagnola hut (MNT; 2,600 m asl; ~3.5 km SE of the summit crater). Since their installation both stations have been continuously recording, resulting in high-resolution (1 Hz sampling rate) time series. The persistent activity of Etna is maintained by a regular supply of magma to the shallower levels of the plumbing system. The bulk mass redistributions induced by the newly injected material result in minor variations in the local gravity field that are recorded by the two stations. By assuming that the observed gravity changes are due exclusively to mass changes in an almost spherical-shaped source, located beneath the craters, the amplitude ratio between the two signals can be used to estimate the depth to potential mass changes beneath the surface.

This study reports on the time-dependent nature of mass changes located beneath the craters of the volcano during 2019. Results highlight distinct periods of stability at different depths, as well as potential periods of transitory activity, where the predominant mass source switches between storage zones at different depth. These events are correlated to phases of strombolian and effusive activity, highlighting the potential of continuous gravimetry for the detection of eruption precursors.
Transpiration of Acacia plantation under managed tropical peatland in Riau, Sumatra
Authors: Suardiwerianto Yogi , Kurnianto Sofyan , Asyhari Adibtya , Muhamad Risky Tubagus , Fikky Hidayat Muhammad , Kurnia Rendy , Shekhar Deshmukh Chandra
Published: March 2021

Transpiration is a key process in the terrestrial ecosystems linking water, carbon, and energy exchanges between the vegetation and the atmosphere. However, the understanding of transpiration rate, its spatiotemporal dynamics, and the controlling factors in tropical peatlands are still constrained by limited measurements. This study aims to investigate the transpiration rates at the stand level of Acacia plantation under different groundwater levels. The measurements were performed at two large-scale lysimeter plots with groundwater level of 40 and 80 cm below the ground surface. The transpiration rate was quantified based on sap flow measurements from 16 trees with different diameters at breast height using heat ratio method. The initial results indicate that the transpiration rate was closely correlated to the meteorological parameters, including atmospheric vapor pressure deficit and solar radiation. The two plots with different groundwater level regimes exhibit the same diurnal pattern of transpiration rate yet shows differences in their magnitude. The findings from this study will improve the understanding about relative contribution of transpiration to the total water balance under different groundwater levels. Further, an ongoing measurement of above and below-ground biomass growth and hydrological modeling work will advance the knowledge on plant-water interaction from this ecosystem.
Extensional detachments related to extreme crustal thinning and their fate during contractional reactivation: the Le Danois-North Mauléon offshore-onshore examples in north Iberia
Authors: Cadenas Patricia , Lescoutre Rodolphe , Manatschal Gianreto
Published: March 2021

Extensional detachment faults accommodate high degrees of crustal thinning and exhumation, shaping largely the final architecture of magma-poor rifted margins. Great efforts have been directed to study extensional detachments based on offshore seismic surveys and onshore field analogues. However, little is known about the breakaway of these structures as well as their role and evolution during rifting and subsequent contractional reactivation. 

In this work, we use the Le Danois-Labourd offshore-onshore natural laboratory (northern Spain) to explore the features characterising major Mesozoic extensional detachment faults and their fate during subsequent Alpine contractional reactivation. Both sites keep evidence of Mesozoic extensional detachment faulting and high degrees of crustal thinning, including exhumed mid-crustal granulites reworked as clasts into Apto-Albian syn-rift sediments, and show mild Alpine reactivation, corresponding at present-day to structural highs. Relying on the interpretation of high quality 2D seismic reflection profiles offshore and on field-based cross-sections onshore, we describe and compare the former rift architecture associated with these major detachment faults and the distribution of contractional structures at the two sites.

 This combined study enable us to evidence strong structural similarities between the two sites and to propose that the Le Danois and the North Mauléon extensional detachment systems are major rift structures within the North Iberian rift system. We propose that they were responsible for high degrees of crustal thinning and the exhumation of mid-crustal rocks during the Late Aptian to Albian N-S directed extension. Major thrusts truncated the two extensional detachments during subsequent Alpine reactivation, leading to the uplift and tilting of the Le Danois and the Labourd rift-inherited crustal blocks. We suggest that the location of the two blocks at the termination of offset/overlapped hyperextended rift segments allowed for their preservation as mildly inverted structural highs, including rift-related structures.
Opening of the West Paleo-Tethys Ocean: New insights from Early Devonian meta-mafic rocks in the southern Saualpe crystalline basement, Eastern Alps
Authors: Liu Yongjiang , Guan Qingbin , Neubauer Franz , Genser Johann , Yuan Sihua , Chang Ruihong , Huang Qianwen
Published: March 2021

Timing of the opening of the West Paleo-Tethys Ocean in Eastern Alps remains controversial. The debate over the timing has revolved mainly around three possible periods, namely Silurian, Early Devonian and Middle–Late Devonian. To constrain this event, we present new zircon U-Pb ages, Hf isotopic compositions, and whole-rock major- and trace-element data for the meta-mafic rocks in the southern Saualpe crystalline basement, Eastern Alps. Zircon U-Pb dating results from three samples yielded crystallization ages of 418 ± 6 Ma, 417 ± 3 Ma and 415 ± 3 Ma, indicating that they formed during the Early Devonian. Geochemically, these meta-mafic rocks have relatively low SiO2 and MgO contents and high TiO2 contents. They are enriched in light rare earth elements (LREE), particularly in Nb and Ta, and show relatively flat heavy rare-earth elements (HREE) patterns, indicating that they have affinities with the alkaline oceanic island basalts (OIB). The geochemical characteristics, together with the positive εHf(t) values of 0.7–11.1, imply that the OIB-like meta-mafic rocks originated from partial melting of a lherzolite source including spinel and garnet. And the primary magma showed complex sources involving the asthenospheric, lithospheric mantle and subducted slab components and subsequently modified by crustal contamination, revealing that the magma formed in a slab window environment associated with mid-ocean ridge subduction. The contemporaneous OIB-like alkaline amphibolites were also found in the central Austroalpine basement and Northwestern Turkey. We suggest that the Late Silurian–Early Devonian OIB-like magmatism is related to a back-arc extension setting in the northern margin of Gondwana leading to the detachment of the European Hunic terranes and hence placing an age on the opening of the West Paleo-Tethys Ocean.
The role of freezing-thaw cycling in rock samples topography evolution and rock cliff retreat
Authors: Fei Li , Derron Marc-Henri , Choanji Tiggi , Jaboyedoff Michel , Sun Chunwei , Wolff Charlotte
Published: March 2021

Freezing-thaw weathering is recognized as one of the most significant factors in the fatigue of rock mass in areas where the temperature periodically fluctuates around the freezing point. 
A one-year monthly SfM monitoring program from December 19, 2019, to January 7, 2021, was done to detect rockfall activity on a rockslide cliff composed of marl-sandstone at La Cornalle, Switzerland. More than one hundred rockfall events were detected during this period with the volumes varied from 0.005m3 to 4.85m3. 
We texture all the rockfalls on the 3D SfM model. It is shown that most of them are mainly located in three areas:  the top of the cliff, the foot of the cliff, and the medium-left part of the cliff. The common feature of these three parts is that the layers are more or less overhanging with dense fractures around them. At the same time, the meteorological data collected by a weather station on site is correlated with the rockfall events to figure out the relationship between each other. Actually, about 30% of total rockfall volume fell during winter on this site. The triggering factor of rockfall during winter is related to freezing-thaw cycling. This kind of weathering can be understood as an interplay between rock properties and its dynamic environment.
In order to make clear the role of freezing-thaw played on the rockfall generation, an on-site 24h monitoring measurement program that consists of two crack meters, one rock thermal sensor, and thermal camera monitoring is installed in January 2021. Those datasets will help to understand how the crack grows with the changing temperature. In addition, freezing-thaw cycling laboratory experiments for the rock samples taken from different areas of the cliff will be done with an environmental test chamber. The topography of the rock samples before and after the experiments will be acquired by a 3D handheld scanner. This work will benefit to reveal the rock surface evolution during the freezing-thaw cycling in a dynamic environment with varied humidity and number of cycles. 
In conclusion, the combination of on-site measurements and laboratory freezing-thaw experiments will provide a good basis for a better understanding of the rockfall triggering mechanism led by physical weathering.
An efficient solution for fast generation of multi-GNSS real-time products
Authors: Zheng Hongjie , Chang Hanyu , Yuan Yongqiang , Wang Qingyun , Li Yuhao , Li Xingxing
Published: March 2021

Global navigation satellite systems (GNSS) have been playing an indispensable role in providing positioning, navigation and timing (PNT) services to global users. Over the past few years, GNSS have been rapidly developed with abundant networks, modern constellations, and multi-frequency observations. To take full advantages of multi-constellation and multi-frequency GNSS, several new mathematic models have been developed such as multi-frequency ambiguity resolution (AR) and the uncombined data processing with raw observations. In addition, new GNSS products including the uncalibrated phase delay (UPD), the observable signal bias (OSB), and the integer recovery clock (IRC) have been generated and provided by analysis centers to support advanced GNSS applications.

       However, the increasing number of GNSS observations raises a great challenge to the fast generation of multi-constellation and multi-frequency products. In this study, we proposed an efficient solution to realize the fast updating of multi-GNSS real-time products by making full use of the advanced computing techniques. Firstly, instead of the traditional vector operations, the “level-3 operations” (matrix by matrix) of Basic Liner Algebra Subprograms (BLAS) is used as much as possible in the Least Square (LSQ) processing, which can improve the efficiency due to the central processing unit (CPU) optimization and faster memory data transmission. Furthermore, most steps of multi-GNSS data processing are transformed from serial mode to parallel mode to take advantage of the multi-core CPU architecture and graphics processing unit (GPU) computing resources. Moreover, we choose the OpenBLAS library for matrix computation as it has good performances in parallel environment.

       The proposed method is then validated on a 3.30 GHz AMD CPU with 6 cores. The result demonstrates that the proposed method can substantially improve the processing efficiency for multi-GNSS product generation. For the precise orbit determination (POD) solution with 150 ground stations and 128 satellites (GPS/BDS/Galileo/GLONASS/QZSS) in ionosphere-free (IF) mode, the processing time can be shortened from 50 to 10 minutes, which can guarantee the hourly updating of multi-GNSS ultra-rapid orbit products. The processing time of uncombined POD can also be reduced by about 80%. Meanwhile, the multi-GNSS real-time clock products can be easily generated in 5 seconds or even higher sampling rate. In addition, the processing efficiency of UPD and OSB products can also be increased by 4-6 times.
Modelling landscape-level pesticide concentrations with SWAT+ - an uncertainty assessment of application timing
Authors: Fuchs Mike , Gebler Sebastian , Lorke Andreas
Published: March 2021

Modelling environmental concentrations of plant protection products at landscape-level is of growing interest for pesticide registration and product stewardship, including higher-tier studies in risk assessment, mitigation measures, monitoring support and decision making. However, landscape-level modelling is challenging due to uncertainties by modelling concepts and scaling as well as the extensive (geo)data demand for model parametrization and validation. This includes also limited information about application timing of pesticide products having strong impact on the model performance predicting pesticide concentrations in water bodies. Our work explores the impact of pesticide application timing using the eco-hydrological model SWAT+ (revised version of Soil and Water Assessment Tool) to explore uncertainty effects of application timing and the underlying mechanisms for the surface water exposure pattern in a small-scale catchment. Specific focus thereby was on method development to mimic realistic application timing considering plant stage, hydrology and weather conditions.

On this account, we setup a SWAT+ model of the Funne catchment (54.6 km²) in the North-West of Germany. The simulated daily streamflow was calibrated using publicly available gauge data (Selm-Ondrup) showing a very good hydrological performance of the model (NSE: 0.746). The impact of application timing was subsequently explored by different synthetic application scenarios for three pesticides with varying physio-chemical properties, in combination with static and rule-based timing options. First results taking runoff and drainage into account indicated that a simple forward oriented ruleset (i.e. using weather forecast) could significantly decrease pesticide loads at the catchment outlet on average by 16 to 46%. For individual years and substances, channel loads decreased by up to 92%, which could be attributed to the interaction of rainfall and wash-off timing as the main driver of concentration variation during runoff events. We will further explore the impact of drift entry and other processes (e.g. channel dissipation) as well as different application schemes.

These findings underpin the importance of realistic application timing in landscape-level simulations of pesticide concentration in surface water bodies. It is hence expected that landscape-level tools will play an important role in the future, e.g., for the development and operation of smart decision tools in agriculture.
Instantaneous multiscale properties of solar wind dynamical regimes and their attractors
Authors: Caby Theophile , Alberti Tommaso , Faranda Davide , Donner Reik V. , Consolini Giuseppe , Vaienti Sandro , Carbone Vincenzo
Published: March 2021

The solar wind is characterized by a multiscale dynamics showing features of chaos, turbulence, intermittency, and recurring large-scale patterns, pointing towards the existence of an underlying attractor. However, magnetic field and plasma parameters usually show different scaling regimes with different physical and dynamical properties. Here by using a recent and novel approach developed in the framework of dynamical systems  we investigate the multiscale instantaneous properties of solar wind magnetic field phase space by means of the evaluation of instantaneous dimension and stability. We show the existence of a break in the average attractor dimension occurring at the observed scaling break between the inertial and the dissipative regimes. We further show that sometimes the dynamics is higher dimensional (d>3) suggesting that the phase space is larger than that described by the system variables and invoking for an external forcing mechanism, together with the existence of at least one unstable fixed point that cannot be definitely associated with noise. Instantaneous properties of the attractor therefore provide an efficient way of evaluating dynamical properties and building up improved cascade models.
VirES for Aeolus - Virtual Research Environment (VRE)
Authors: Santillan Pedrosa Daniel , Geiss Alexander , Krisch Isabell , Weiler Fabian , Fischer Peggy , Troina Giuseppe
Published: March 2021

The VirES for Aeolus service (https://aeolus.services) has been successfully running by EOX since August 2018. The service provides easy access and analysis functions for the entire data archive of ESA's Aeolus Earth Explorer mission through a web browser.

This free and open service is being extended with a Virtual Research Environment (VRE). The VRE builds on the available data access capabilities of the service and provides a data access Application Programming Interface (API) as part of a developing environment in the cloud using JupyterHub and JupyterLab for processing and exploitation of the Aeolus data. In collaboration with Aeolus DISC user requirements are being collected, implemented and validated.

Jupyter Notebook templates, an extensive set of tutorials, and documentation are being made available to enable a quick start on how to use VRE in projects. The VRE is intended to support and simplify the work of (citizen-) scientists interested in Aeolus data by being able to quickly develop processes or algorithms that can be shared or used to create visualizations for publications. Having a unified constant platform could potentially also be very helpful for calibration and validation activities by allowing easier result comparisons.
Unusual Mw 7.0 Extensional Aegean Earthquake Related to African Slab Rollback and Formation of Extensional Plate Boundary in Anatolia 
Authors: Meng Jiannan , Sinoplu Ozan , Zhou Zhipeng , Tokay Bulent , Kusky Timothy , Bozkurt Erdin , Wang Lu
Published: March 2021

A devastating M 7.0 earthquake on October 30, 2020, offshore Samos Island, Greece, was a consequence of the Aegean and Anatolian upper crust being pulled apart by north-south extensional stresses resulting from slab rollback, where the African plate is subducting northwards beneath Eurasia, while the slab is sinking by gravitational forces, causing it to retreat southwards. Since the retreating African slab is coupled with the overriding plate, it tears the upper plate apart as it retreats, breaking it into numerous small plates with frequent earthquakes along their boundaries.  The earthquake happened offshore of the extensional Büyük Menderes Graben, where a 150 km long, 10 km wide, incipient upper plate rift system formed in the Anatolian plate, showing that the entire Aegean-Western Anatolian region is being pulled apart by extensional stresses related to the slab rollback. Earthquake solutions and fault plane studies around western Anatolia support this spectacular extension, and show that the modern extension was preceded on many faults by oblique extension and strike-slip motions, perhaps reflecting a change in tectonic setting from sideways escape from the Africa-Arabia collision with Eurasia,  to the pure extension related to slab rollback of the African plate, and the retreat of the Hellenic trench. Historical earthquake swarms and deformation of the upper plate in the Aegean have been associated with massive volcanism and cataclysmic devastation, such as the M 7.7 Amorgos earthquake in July 1956 between the islands of Naxos and Santorini (Thera). Even more notable was the eruption of Santorini 3650 years ago, which contributed to the fall of the Minoan civilization. The Samos earthquake highlights the long historical lack of appreciation of links between deep tectonic processes and upper crustal deformation and geological hazards, and is a harbinger of future earthquakes and volcanic eruptions, establishing a basis for studies to institute better protection of infrastructure and upper plate cultures in the region. Further detailed studies are needed in this area to better understand and predict earthquake frequency, possible locations, and to establish better building codes to protect people's lives and property.
Dry-spell assessment through rainfall downscaling comparing deep-learning algorithms and conventional statistical frameworks in a data scarce region: The case of Northern Ghana
Authors: Mavritsakis Panagiotis , ten Veldhuis Marie-Claire , Schleiss Marc , Taormina Riccardo
Published: March 2021

Large parts of the world rely on rainfed agriculture for their food security. In Africa, 90% of the agricultural yields rely only on precipitation for irrigation purposes and approximately 80% of the population’s livelihood is highly dependent on its food production. Parts of Ghana are prone to droughts and flood events due to increasing variability of precipitation phenomena. Crop growth is sensitive to the wet- and dry-spell phenomena during the rainy season. To support rural communities and small farmer in their efforts to adapt to climate change and natural variability, it is crucial to have good predictions of rainfall and related dry/wet spell indices.

This research constitutes an attempt to assess the dry-spell patterns in the northern region of Ghana, near Burkina Faso. We aim to develop a model which by exploiting satellite products overcomes the poor temporal and spatial coverage of existing ground precipitation measurements. For this purpose 14 meteorological stations featuring different temporal coverage are used together with satellite-based precipitation or cloud top temperature products.

We will compare conventional copula models and deep-learning algorithms to establish a link between satellite products and field rainfall data for dry-spell assessment. The deep-learning architecture used should be able to both have the feature of convolution (Convolutional Neural Networks) and the ability to capture a sequence (Recurrent Neural Networks). The deep-learning architecture used for this purpose is the Long Short-Term Memory networks (LSTMs). Regarding the copula modeling, the Archimedean, the Gaussian and the extreme copulas will be examined as modeling options.

Using these models we will attempt to exploit the long temporal coverage of the satellite products in order to overcome the poor temporal and spatial coverage of existing ground precipitation measurements. Doing that, our final objective is to enhance our knowledge about the dry-spell characteristics and, thus, provide more reliable climatic information to the farmers in the area of Northern Ghana.
A Machine Learning technique for ULF wave classification in Swarm magnetic field measurements
Authors: Antonopoulou Alexandra , Balasis George , Papadimitriou Constantinos , Boutsi Zoe , Giannakis Omiros , Koutroumbas Konstantinos , Rontogiannis Athanasios
Published: March 2021

Ultra-low frequency (ULF) magnetospheric plasma waves play a key role in the dynamics of the Earth’s magnetosphere and, therefore, their importance in Space Weather studies is indisputable. Magnetic field measurements from recent multi-satellite missions are currently advancing our knowledge on the physics of ULF waves. In particular, Swarm satellites have contributed to the expansion of data availability in the topside ionosphere, stimulating much recent progress in this area. Coupled with the new successful developments in artificial intelligence, we are now able to use more robust approaches for automated ULF wave identification and classification. The goal of this effort is to use a machine learning technique to classify ULF wave events using magnetic field data from Swarm. We construct a Convolutional Neural Network that takes as input the wavelet power spectra of the Earth’s magnetic field variations per track, as measured by each one of the three Swarm satellites, aiming to classify ULF wave events in four categories: Pc3 wave events, background noise, false positives, and plasma instabilities. Our primary experiments show promising results, yielding successful identification of 90% accuracy. We are currently working on producing larger datasets, by analyzing Swarm data from mid-2014 onwards, when the final constellation was formed.