bluuebunny/crossref_metadata_2025 huggingface dataset:
Captured metagenomics reveals high spatial variability in functional potential in CH4 producing and consuming microorganisms in a temperate Swedish peatland.
Authors: White Joel , Ström Lena , Ahrén Dag , Rinne Janne , Lehsten Veiko
Published: March 2021

Microbial communities of methane producing methanogens and consuming methanotrophs play an important role for the earths atmospheric methane budget. Despite their global significance, the functional potential of these communities is poorly understood. To investigate this, we applied the molecular technique, captured metagenomics, to identify the variability in functional diversity of microorganisms involved in the metabolism of methanein an environmentally controlled laboratory study. Nine plant-peat mesocosms dominated by the sedge Eriophorum vaginatum, with varying coverage, were collected from a temperate natural wetland is Sweden and subjected to a simulated growing season. Samples for analysis of captured metagenomes were taken from the top, bottom and root adjacent zone at the end of the experiment. In addition, over the simulated season, measured gas fluxes of carbon dioxide (CO2) and CH4, δ13C of emitted CH4 and the pore water concentration of dissolved methane and low molecular weight organic acids were recorded. The functional genes resulting from the captured metagenomes had a higher Shannon α-diversity in the root zone when compared to the bottom and top. Sequences coding for methane metabolism were significantly more diverse in the root and bottom zones when compared to the top. However, the frequency of Acetyl-CoA decarbonylase and methane monooxygenase subunit A were significantly higher in the high emitting methane flux category when compared to the medium and low emitting mesocosms. We conclude that captured metagenomic analyses of functional genes provides a good measure of the functional potential methanogenic and methanotrophic microbial communities. This technique can be used to investigate how methanogens and methanotrophs function in peatlands and thus, contribute to the concentration of atmospheric methane.
Chemical characteristics and optical properties of brown carbon aerosol in Karlsruhe during winter
Authors: jiang feng , Saathoff Harald , song junwei , gao linyu , vallon magdalena , leisner thomas , norra stefan
Published: March 2021

Brown carbon (BrC) aerosol has significant climatic impact due to its ability to absorb solar radiation in the near-ultraviolet and visible spectral range. However, chromophores responsible for light absorption in atmospheric aerosol particles are not well understood in urban areas. Therefore, optical properties and chromophore composition of brown carbon were characterized during March 2020 in downtown Karlsruhe, a city of 300000 inhabitants in southwest Germany.

In this study, total non-refractory particle mass was measured with a high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-MS; hereafter AMS). Furthermore, Aerosol particles were collected on filters and analyzed in the laboratory. Filter samples were extracted by methanol and the corresponding solutions were analyzed by excitation-emission spectroscopy (AquaLog), resulting in characteristic light absorption and fluorescence spectra. Furthermore, filters were analyzed by a filter inlet for gases and aerosols coupled to a high-resolution time-of-flight chemical ionization mass spectrometer (FIGAERO-HR-TOF-CIMS; hereafter CIMS) employing iodide ions, which results in the molecular composition of oxygenated organic aerosol compounds.

Our results show that the average light absorption and mass absorption efficiency of brown carbon at 365 nm were (2.8±1.9) Mm-1 and (1.1±0.2) m2 g-1 respectively. Parallel factor (PARAFAC) analysis allowed for identification of four types of fluorescence in methanol-soluble organic compounds. HULIS-like compounds contributed 47%, road dust-like compounds 19%, biomass burning-like compounds 25%, and protein-like compounds 9%. Positive matrix factorization (PMF) analysis of organic detected by AMS led to five characteristic organic compound classes. Of these five classes, the biomass burning organic aerosol showed a correlation coefficient of r2=0.7 with the biomass burning like factor from the fluorescence analysis. Oxygenated organic aerosol components had potentially lower fluorescence intensity and mass absorption coefficiency. Furthermore, five nitroaromatic compounds were identified by CIMS (C7H7O3N, C7H7O4N, C6H5O5N, C6H5O4N, and C6H5O3N) which contributed 0.2%-0.9% to total organic mass, but can explain 3%-6% of the absorption at 365 nm.
Blueschist facies conditions in Tethyan passive margin metabasaltic rocks of the easternmost Lower Alpujarride Units (Internal Betic Zone, Spain)
Authors: Santamaría-Pérez Eva , Blanco-Quintero Idael Francisco , Martín-Algarra Agustín , Benavente David , Cañaveras Juan Carlos , González-Jiménez José María , Garcia-Casco Antonio
Published: March 2021

Jurassic shallow-intrusive basic bodies within the Permian-Triassic Tethyan passive margin sedimentary sequences of the Lower Alpujarride units (Internal Betic Zone, Spain) locally show Alpine low-grade metamorphism in the greenschist and blueschist facies. A small sill-like mafic body near Redován town (Callosa Range) partially preserves igneous ophitic/subophitic texture and relics of augite, ferrohornblende-ferroedenite, kaersutite and K-feldspar (orthoclase). The metamorphic overprint corresponds to high-pressure and low-temperature mineral assemblages that comprise magnesioriebeckite, actinolite, albite, stilpnomelane, phengite and chlorite, with rutile, apatite and titanite as accessory minerals. Major and trace element geochemical data reveal igneous protoliths derived from magmas of alkaline basalt composition enriched in incompatible elements and E-MORB geochemical affinity. The intrusion emplacement occurred at shallow crustal levels in an extensional geodynamic setting (within-plate basalts) related to the breakoff of Pangea. Pressure-Temperature (P-T) conditions estimated by means of pseudosection calculations and the intersection of phengite (Si) and chlorite (Mg#) isopleths indicate a cold thermal gradient with calculated peak metamorphic conditions of ca. 8 kbar at 310 ºC. These conditions are consistent with metamorphism during burial down to ca. 24 km depth and a thermal gradient of ca. 13 ºC/km. Although the easternmost Lower Alpujarride units have been traditionally described as reaching only lower-greenschist to greenschist metamorphic peak conditions, the textures, mineral compositions and P-T conditions of the studied metagabbroic body reveal blueschist facies conditions that attest for a regional early stage (Eocene) of subduction of the lower Alpujarride units. This event predates the late Oligocene - early Miocene subduction-related metamorphism of the Intermediate and Upper Alpujarride units.
Correcting model error with an online Artificial Neural Network
Authors: Chrust Marcin , Bonavita Massimo , Laloyaux Patrick
Published: March 2021

In both Numerical Weather Prediction and Climate Prediction, achieving improved accuracy and reliability is fundamentally dependent on identifying the sources and reducing the effects of model error. It has been recently demonstrated (Laloyaux et al., 2020) that weak constraint 4D-Var can estimate and correct for a large fraction of model error in the stratosphere, where the current global observing system is sufficiently dense and homogeneous. Accounting for the model error in the entire atmospheric column, specifically in the troposphere, remains challenging due to the difficulty in disentangling different sources of errors with similar spatial scales, and is the focus of current research.

In this work we demonstrate how Deep Learning techniques can be applied to the problem of estimation and online correction of model error. Recent results (Bonavita and Laloyaux, 2020) in the ECMWF Integrated Forecasting System (IFS) have shown that model error can be learned by an Artificial Neural Network (ANN) and applied in a weak constraint 4D-Var data assimilation framework as a model tendency forcing term. Moreover, the error estimation can extend to the whole atmospheric column and result in significantly improved analyses and forecasts. We have recently implemented in the ECMWF IFS the capability of applying online such ANN-based model error. This allows us to extend the application of the ANN-based model error parameterization from the data assimilation cycle to the long forecast step, where a model error tendency correction is continuously estimated and applied as a model forcing. We show preliminary results of the experiments conducted in the IFS framework and discuss our current understanding of the advantages and limitations of these techniques.
Evaluating river driftwood potential for energy storage applications 
Authors: Qatarneh Abdullah F , Dupont Capucine , Ruiz-Villanueva Virginia , Michel Julie , Simonin Loic , Piégay Hervé , Franca Mário J.
Published: March 2021

Around the world rivers transport large volumes of driftwood into lakes, seas and oceans. Recruited commonly during flooding events and transported by rivers, driftwood poses a hazard for the point of view of the safety of infrastructures and river dwellers. For that reason, it is many times extracted locally and stored; driftwood removal prevents sinking and protects the dam infrastructure. Collected driftwood is a neglected river resource that is generally combusted or landfilled. Génissiat dam on the Rhone River in France presents a case study where annually approximately 1300 tons of driftwood is intersected.

 

Among the different processes that are capable of converting driftwood, HydroThermal Carbonization (HTC) is of high interest due its ability to process biomass with high moisture content, such as driftwood. HTC of biomass leads to the production of a solid product referred to as hydrochar, which is a high added-value material that can be used in different applications, such as fuel cooking, soil amendment, water treatment and energy storage. The goal of the study was to characterize the driftwood collected upstream of the Génissiat dam and to investigate its potential for hydrochar production as precursor of anode in sodium-ion batteries. Sodium-ion batteries have received more interest lately as an alternative for the resource intensive and expensive lithium-ion batteries.  The study follows a novel approach in study driftwood by categorizing based on their genera. HTC of the different identified genera was conducted in a 2L batch reactor following a temperature of 200 °C for a residence time of 11.5 h. Results show that the impact of driftwood genera is not significant for processing of driftwood through HTC. Produced hydrochar had a high carbon content (from 55.4 to 57.0 %) and lower ash content (from 0.2 to 1.4 \% of dry biomass). Electrochemical results show that driftwood-based hydrochar is a promising precursor of hard carbon anodes in sodium-ion batteries due to its excellent electrochemical performance.

 

Key words: Driftwood, Hydrothermal carbonization, Hydrochar, Rhone river, Sodium-ion batteries
Using an emulator to apply a Carbon Takeback Obligation alongside demand-side carbon pricing in Integrated Assessment Models
Authors: Jenkins Stuart , Mitchell-Larson Eli , Ives Matthew , Haszeldine Stuart , Allen Myles
Published: March 2021

Integrated Assessment Model (IAM) design philosophy currently focuses on demand-side global carbon pricing as the principal policy tool to drive mitigation. However, ambitious mitigation scenarios produced with these IAMs rely heavily on the availability of carbon capture and storage (CCS) technologies in the mid-century, at the scale of billions of tonnes. If integrated assessment continues to employ demand-side policies exclusively we risk a gap forming between the requirements of economically-optimal mitigation trajectories in these IAMs and the reality of developed CCS capacity.

If CCS capacity fails to keep up with the ambition of mitigation policy, carbon prices could rise well above the cost of direct air capture as markets aim to drive residual emissions down. To avoid this, scenarios could include both supply and demand-side policies in tandem, where supply-side policies are targeted to increase CCS capacity to appropriate levels.

One such supply-side policy option is a Carbon Takeback Obligation (CTBO), where suppliers of fossil carbon are required to recapture and store an increasing fraction of the carbon in their products. This ‘stored fraction’ would be increased from near zero at present, up to 100% at the time of net-zero. By applying such a policy suppliers of fossil carbon products are forced to take responsibility for decarbonising their own products and provide the drive to develop the CCS capacity necessary to achieve net-zero emissions in the mid-century. In theory, if a CTBO was enforced globally the costs associated with the production of one tonne of CO2 would be capped around the price for the capture, transport and storage of diffuse, mobile, or otherwise hard-to-abate CO2 emission sources (i.e. the cost of direct air capture).

Here, we discuss the implementation of a global CTBO. Using an Integrated Assessment Model emulator, tuned to existing IAM carbon price/abatement rate relationships, we explore the total policy cost of applying a CTBO globally to achieve net-zero by 2050. Using the emulator we harmonise the combined CTBO and demand-side carbon price policies, and show how a SSP2-26 level of ambition can be achieved using these policies with a similar total policy cost. Further, we explore what additional near-term carbon prices can be included to achieve SSP2-19 level policy ambition. These results suggest there are significant benefits to defining climate policy around measures targeting suppliers of fossil carbon, including for long-term planning, implementation and governance of the policy, and overall cost. For further insight, and to provide a greater variety of policy options feeding into IPCC’s WG3, we argue IAMs should look to include CTBO-like policies in future scenario design.
Structural framework and the timing of landscape-forming faults - a study from Western Norway
Authors: Hestnes Åse , Gasser Deta , Scheiber Thomas , Jacobs Joachim , Ksienzyk Anna K. , van der Lelij Roelant , Schönenberger Jasmin
Published: March 2021

Brittle fracture and fault networks control the location of topographic features such as valleys and ridges and active faulting can lead to topographic rejuvenation. In Western Norway, however, it is debated how much faulting has contributed to rejuvenating of the topography during the late Mesozoic and Cenozoic. Geometric and temporal constraints on the brittle evolution are therefore important to obtain a comprehensive picture of the post-Caledonian topographic evolution of this region. In this study, we combine remote sensing, structural field measurements, paleo-stress analysis and isotopic dating to study the brittle evolution of a larger region of Western Norway. The region spans from the Sognefjord in the south to the Møre margin in the north. Lineament studies reveal important lineament sets trending N-S, NE-SW, E-W and NW-SE. Field observations show that these lineament sets correspond to both dip-slip and strike-slip faults, some of them parallel to ductile precursor structures and some cutting the ductile fabric. Epidote, chlorite, quartz and zeolite are the dominant mineralizations on fracture and fault surfaces. There is no clear correlation between the type of mineralization and fracture orientation in the region. Paleostress analysis on fault-slip data (n = 173), including faults reactivating older structures, show a good fit with a general E-W extensional regime. However, a considerable amount of faults (n = 115) formed under a strike-slip regime, which has so far not been documented in the region. We combine these findings with K-Ar fault gouge dating from six faults where five fractions (6-10 µm, 2-6 µm, 0.4-2 µm, 0.1-0.4 µm, <0.1µm) from each sample were analysed. These faults represent two of the four fracture sets observed, trending N-S and NE-SW, respectively, and show either strike-slip or dip-slip kinematics. XRD-data from these gouges show that K-feldspar and smectite are the main sources of potassium. The ages show a spread from the Triassic to the Cretaceous, where older ages can be affected by K-feldspar inherited from the host rock. Our results point to an important phase of Mesozoic strike-slip faulting in the region, with steep faults controlling the location of several major valleys. Extensional dip-slip faults might have contributed to the rejuvenation of the footwall topography.
Projected increases in surface melt and ice loss and their potential feedbacks for the Northern and Southern Patagonian Icefields 
Authors: Bravo Claudio , Bozkurt Deniz , Ross Andrew N. , Quincey Duncan J.
Published: March 2021

Patagonia (40°S-55°S) includes two large icefields, the Northern and Southern Patagonian Icefields (NPI and SPI). Most of the glaciers within these icefields are shrinking rapidly, raising concerns about their contribution to sea-level rise in the face of ongoing climatic change. This ice volume loss has led to rapid changes that remain imprinted on the Patagonia landscapes. In view of the local, regional and worldwide impacts of glacier retreat in Patagonia, an assessment of the potential future surface mass balance (SMB) and ice loss of the icefields, is critical. We seek to provide this assessment by modelling the SMB between 1976 and 2050 for both icefields, using regional climate model data (RegCM4.6) and a range of emission scenarios at a spatial resolution of 10 km. Additionally, using meteorological observations during strong drought conditions which occurred in Patagonia in 2016, key meteorological and glaciological characteristics are described, quantified and analysed in order to assess possible future conditions.

For the NPI, a reduction between 1.51 m w.e.  (RCP2.6) and 1.88 m w.e. (RCP8.5) was projected, suggesting that negative SMB will prevail well into future decades. For the SPI the projected reduction was within the range of 1.12 m w.e. (RCP2.6) to 1.45 m w.e. (RCP8.5), which implies positive SMB will dominate, albeit at a lower rate than the current observed. However, if it is assumed that the recent frontal ablation rates tend to continue into future decades, ice loss and sea-level contributions will increase for both Icefields. The trend towards lower SMB is explained by an increase in melt, and to a lesser extent by a reduction in snow accumulation.

Several mechanisms not accounted for our modelling approach could act as positive feedbacks in the magnitude of the ice loss. We summarise these feedbacks in a conceptual framework based on a combination of our own meteorological observations as well as on the recent research findings. This framework highlights the diversity of meteorological and glaciological conditions that can prevail even between nearby glaciers. Importantly, more frequent thermal inversion events and increased meltwater availability are likely to trigger ice dynamics changes and potential increases in ablation. Together, these plus other factors make the prediction of future glacier response and evolution in Patagonia a very complex and challenging task.
Road Construction and Rainfall as Landslide Triggers in the Rio Lucma Catchment, Eastern Cordillera Blanca, Peru
Authors: Abad Lorena , Hölbling Daniel , Emmer Adam
Published: March 2021

Extensive road construction works were recently undertaken in the remote eastern part of the Peruvian Cordillera Blanca, aiming at better connecting isolated mountain communities with regional administrative centres. In the Río Lucma catchment, approximately 47 km of roads were constructed between 2015 and 2018, triggering several landslides that affected an approximate area of 32 ha. We identified and characterised these landslides by combining field mapping, visual interpretation and semi-automated analysis of satellite imagery (PlanetScope and RapidEye-2), and analysis of rainfall data from two stations of the Servicio Nacional de Meteorología e Hidrología del Perú (SENAMHI). We investigated in detail three specific areas of interest, where we identified, delineated, and described 56 landslides. We classified the landslides in relation to their position to the road as: landslides downslope the roads (48.2%), complex landslides crossing the roads (46.4 %), and landslides onto the road (5.3%). According to the type of movement, we found that the slide-type movement (60.7%) prevails over the flow-type movement (39.3%). Timewise, we found that 75% of landslides were observed on satellite imagery simultaneously with road construction work, while the remaining 25% were identified between one week and seven months after the roads had been constructed. We analysed lagged cumulative rainfall data against the occurrence of these subsequent landslides, determining that a two-week rainfall accumulation can act as triggering factor of landslides after road construction work. In general, 51% of the landslides were observed during the wet season (November to April) while 41.1% occurred during El Niño–Southern Oscillation (ENSO) strong cool phase or “La Niña” period. We observed that the majority of mapped landslides were directly (e.g., landslides resulting from slope undercutting) or indirectly associated with road constructions (e.g., rainfall-induced landslides resulting from a combination of extreme precipitation over slopes with decreased stability) and that the road constructions also may set preconditions for subsequent rainfall-triggered landslides.
Is the flow of water over a crayfish in a river the same as the flow of air over a Formula One car; opportunities and challenges of outreach and engagement in the geosciences
Authors: Ockelford Annie
Published: March 2021

As geoscientists we are used to being inspired by and seeing the physical and scientific value of the landscapes surrounding us. We are also used to questioning why and how landscapes evolve and as well as trying to unravel the complex interactions between the human and physical landscapes.  However, typically scientific results remain within the scientific community and there is relatively little engagement beyond that community particularly with underrepresented or hard-to-reach audiences.    

From making slime glaciers to discussing whether or not the flow of water over a crayfish in a river is the same as the flow of air over a Formula One car, running geoscience themed outreach and engagement events have provided me with some of the most exciting and rewarding times of my academic career.  In this lecture I will share some of the passion I have for ensuring academic research is shared, is accessible and is inspiring for everyone, not just scientists.  Using examples of how I have engaged with a diverse range of non-academic audiences from school children to governmental policy makers I will talk through the challenges and opportunities these engagement experiences have presented.

Looking to the future I will discuss the potential opportunities the geoscience community has for overcoming current barriers to engagement, the significance of training undergraduate and postgraduate students in delivering engagement activities and the importance of engaging citizens with scientists in order to understand and help mitigate against the impact humans are having on our fragile planet.
Hydrological processes and water flux quantification in agricultural fields under different tillage and irrigation systems using water stable isotopes
Authors: Canet-Marti Alba , Morales-Santos Angela , Nolz Reinhard , Langergraber Günter , Stumpp Christine
Published: March 2021

Sustainable agriculture should be based on management practices that improve resource usage efficiency and minimize harmful impacts on the environment while maintaining and stabilizing crop production. Both tillage and irrigation can have a great influence on hydrological processes within agroecosystems. However, it remains difficult to directly assess the effect of practices on water fluxes which has been mainly indirectly quantified by complex numerical modelling methods in the past. Therefore, the objective of the study was to use a space for time concept and measure oxygen and hydrogen isotopes (δ18O, δ2H) in the pore water of soil profiles as well as moisture contents for quantifying the soil water balance and fluxes. Covering all combinations, soil profiles and isotope analysis was performed for 16 sites planted with winter wheat and managed with different tillage (conventional tillage (CT), reduced tillage (RT), minimal tillage (MT), and no-tillage (NT)) and irrigation systems (hose reel boom irrigation with nozzles (BI), sprinkler irrigation (SI), drip irrigation (DI) and no irrigation (NI)). The results indicated that the more intense the tillage, the lower the water content. Among the irrigation systems, DI had the highest average water content. Tracing the minimum in the isotopic composition of the pores water within the depth profiles showed a deeper percolation of water in the CT fields, which indicates higher water flow velocity. Considering both water content and differences in water flow velocities resulted in water fluxes ranging from 90 to 151 mm yr-1. The losses due to evapotranspiration varied between 57 and 80%. The resulting evapotranspiration within tillage and irrigation variants decreased in the order RT>CT≈MT>NT, and SI>BI>DI>NI. Thus, the method revealed that the lower water content in CT fields is a consequence of deeper water infiltration. Moreover, irrigation water contributed mostly to evapotranspiration, and drip irrigation showed the lowest evapotranspiration losses among irrigation systems. This study demonstrated that water stable isotopes can be used as indicators and are a promising method to quantify water fluxes in agricultural fields with great potential for evaluating management practices.
Mind the gap: New insights on large-scale forest dynamics over Amazonian forests from airborne lidar and canopy gap data
Authors: Dalagnol Ricardo , Wagner Fabien H. , Galvão Lênio S. , Streher Annia S. , Phillips Oliver L. , Gloor Emanuel , Ometto Jean P. H. B. , Aragão Luiz E. O. C.
Published: March 2021

Tree mortality has been pointed out as a key factor to quantify global forests carbon stocks and turnover. While there have been recent developments on observational studies aiming at detection and attribution of tree mortality using remote sensing data in temperate forests, the spatial and temporal distribution of tropical forests mortality is still poorly understood. Tropical forests pose a challenge for mortality detection due to its rich diversity of plant species and heterogeneous canopy structure, which also leads to the occurrence of very frequent and localized mortality events rather than widespread mortality as seen in some temperate forests. Here, we report on recent developments on estimates of spatialized forest dynamics over tropical forests leveraging large datasets of airborne lidar and a newly established link between canopy gaps and canopy mortality. Using multi-temporal lidar datasets collected at five Brazilian Amazon forests with varied forest structure, we linked static gaps, i.e. holes in the forest observed at one date, to dynamic gaps, i.e. gaps that opened from one date to another. Using 610 flight lines of airborne lidar data covering an area >2,300 km² across the Brazilian Amazon, we mapped the static gaps and used them to analyze potential natural and human-induced drivers using generalized linear models. Finally, we produced estimates of annual dynamic gap rates (% yr-1) for the whole Amazon using the combination of the environmental-climate model and the static-dynamic gaps relationship. Our findings show well-defined spatial patterns of dynamic gaps over the Amazon, with 20-35% faster dynamics in the west and southeast than in the central-east and north. Higher gap fractions were more often found at southern and eastern Brazilian Amazon, bordering the ‘deforestation arch’, i.e. regions with increased human influence. Dynamic gaps showed a significant relationship with field mortality rates (R² = 0.40), but with 60% lower magnitude. In fact, what we have detected is very likely mortality with the predominant emphasis of lidar on detecting uprooted and broken mode of death. The analysis also provided new insights on the dynamics of remote areas where we have never visited before. New challenges include testing the gap-method over other sites with multi-temporal data, developing methods to detect standing dead trees, and mapping other drivers such as liana-infested forests. Merging improved regional quantification of dynamic gap estimates with vegetation modelling offers potential to explore how forest dynamics is influencing carbon stocks and turnover, and how they may evolve in the future.
Long-term temporal analysis of four Pyrenean catchments with a gradient of land-cover
Authors: Juez Carmelo , Nadal-Romero Estela
Published: March 2021

Land cover and historical land use practices are the leading drivers of the hydrological response in most catchments systems. Timing, periodicity and magnitude of precipitation-discharge feedbacks are thus impacted by such site-specific characteristics. We analysed the long-term precipitation and discharge databases of four experimental catchments located in the Central Spanish Pyrenees and thus similar in their climate. Furthermore, they have a gradient of land cover (from a relatively pristine forested catchment, through an abandoned cultivated catchment with progressive plant recolonization, to an afforested catchment and ending by a bare degraded badland catchment); so, form a solid benchmark to assess such dynamic changes. For the analysis of the long-term precipitation and discharge time-series we use the wavelet transform methodology, which proves valuable to segregate the continuous hydrological response of the catchments in different and non-similar dominant time-scales. Precipitation and discharge events are not just identified and analysed in terms of magnitude or correlation relationships but also the time-localization of each transient precipitation and discharge events is retrieved. We thus no impose any fixed periodicity in the occurrence of hydrological events and ultimately, we are able to infer the real and site-specific temporal variability of each dataset through which we can infer the timing, variability and physical mechanisms of water storage/transport in each catchment. Thereby, this analysis reveals the land-cover-discharge feedbacks that takes place at different time-scales.
Landslides, river incision and environmental change: the Ruzizi gorge in the Kivu Rift
Authors: Mugaruka Bibentyo Toussaint , Dille Antoine , Depicker Arthur , Smets Benoît , Vanmaercke Matthias , Nzolang Charles , Dewaele Stijn , Dewitte Olivier
Published: March 2021

The understanding of the interplay between natural and human induced factors in the occurrence of landslides remains poorly constrained in many regions, especially in tropical Africa where data-scarcity is high. In these regions where population growth is significant and causes changes in land use/cover, the need for a sustainable management of the land is on the rise. Here, we aim to unravel the occurrence of landslides in the 40 km-long Ruzizi gorge, a rapidly incising bedrock river in the Kivu Rift in Africa that has seen its landscape disturbed over the last decades by the development of the city of Bukavu (DR Congo). Careful field observations, historical aerial photographs, satellite imagery and archive analysis are combined to produce a multi-temporal inventory of 264 landslides. We show that the lithological context of the gorge and its extremely high incision rate (> 20 mm year-1) during the Holocene explains the presence of a concentration of large landslides (up to 2 km²) of undetermined age (well before the first observations of 1959) whose occurrence is purely natural. They are mostly of the slide type and do not show morphologic patterns of recent activity. The landslides that occurred during the last 60 years are flow-like shallower slope failures of smaller size (up to 0.12 km²) and tend to disappear rather quickly (sometimes within a few years) from the landscape as a result of rapid vegetation growth, land reclamation and (human-induced) soil erosion. They are primarily related to threshold slopes and precipitation plays a frequent role in their onset. However, land use/cover changes also affect their occurrence. This study provides useful information for a more accurate evaluation of the landslide hazard in the area, particularly with respect to the growth of the city of Bukavu that has developed without the consideration of naturally instable slopes. It also stresses the need and added value of building accurate landslide inventories in data-scarce regions.
Subduction dynamics and rheology control on forearc and backarc subsidence: Numerical models and observations from the Mediterranean  
Authors: Balazs Attila , Faccenna Claudio , Gerya Taras , Ueda Kosuke , Funiciello Francesca
Published: March 2021

The dynamics of oceanic and continental subduction zones is linked to the rise and demise of forearc and backarc basins in the overriding plate. Subsidence and uplift rates of these distinct sedimentary basins are controlled by variations in plate convergence and subduction velocities and determined by lithospheric rheological structure and different lithospheric thicknesses.

In this study we conducted a series of high-resolution 2D numerical models applying the thermo-mechanical code 2DELVIS (Gerya and Yuen, 2007). The model, based on finite differences and marker-in-cell techniques, solves the mass, momentum, and energy conservation equations for incompressible media; assumes elasto-visco-plastic rheologies and involves erosion, sedimentation and hydration processes.

The models show the evolution of wedge-top basins lying on top of the accretionary wedge and retro-forearc basins in the continental overriding plate, separated by a forearc high. These forearc regions are affected by repeated compression and extension phases. Higher subsidence rates are recorded in the syncline structure of the retro-forearc basin when the slab dip angle is higher and the subduction interface is stronger and before the slab reaches the 660 km discontinuity. This implies the importance of the slab suction force as the main forcing factor creating up to 3-4 km negative dynamics topographic signals.

Extensional back-arc basins are either localized along inherited crustal or lithospheric weak zones at large distance from the forearc region or are initiated just above the hydrated mantle wedge. During trench retreat and slab roll-back the older volcanic arc area becomes part of the back-arc region. Back-arc subsidence is primarily governed by crustal and lithospheric thinning controlled by slab roll-back. Onset of continental subduction and soft collision is linked to the rapid uplift of the forearc basins; however, the back-arc region records ongoing extension. Finally, during hard collision the forarc and back-arc basins are ultimately under compression.

Our results are compared with the evolution of the Mediterranean and based on the reconstructed plate kinematics, subsidence and heat flow evolution we classify the Western and Eastern Alboran, Paola and Tyrrhenian, Transylvanian and Pannonian Basins to be genetically similar forearc–backarc basins, respectively.
Human in nature: two cases on social factors nested in the implementation of Nature-based Solutions
Authors: Weng Wei , Costa Luís , Lüdeke Matthias , Zemp Delphine , Jou Sue-Ching , Jaramillo Fernando , Liu Mei-Yi
Published: March 2021

Nature-based Solutions (NbS), inspired or supported by nature, aim to address societal challenges in a fast-changing environment via an integrated and sustainable approach. Effective implementation of such intervention certainly requires compliance with specific societal configurations in different geographies. Here two cases of NbS to hydrological disaster risks are used to demonstrate the relevance of social barriers and opportunities for the full function of NbS.

Firstly, we introduce a novel large-scale NbS designed for reducing water scarcity in the Bolivian city of Santa Cruz de la Sierra. In this case, strategic reforestation was planned to bring rainfall to a downwind city taking advantage of atmospheric moisture pathways. In the process of co-designing reforestation sites, experiences from failed reforestation projects have improved the site selection originally based solely on the scientific evidence of the moisture pathways. Social barriers to implementation include underground economic activities and pressures for local food production. The latter factor also implies a trade-off between the fulfilments of different sustainable development goals.

Secondly, a case of landscape-scale NbS that aims to mitigate flood risk from typhoons in Taiwan will be discussed. It consists of a flood diversion framework that directs excess runoff to local farmlands following Typhoon storms. The concept of payment for ecosystem services has been employed to increase the willingness of farmers and landowners to participate in this framework. Institution of compensation for agricultural loss established from previous meteorological disasters has paved the way for implementation. A combination of subsidies and agricultural loss compensation has offered an opportunity for the new intervention to take place in the rice-cropping landscape, while the effect of this ongoing framework will be further documented.

These two cases show that the inertia from existing policy/institutional schemes and the lessons from past unsuccessful experiences provide an opportunity to identify and overcome social barriers to the implementation of innovative NbS.
Karman-Howarth-Monin equation for compressible Hall MHD  turbulence: 2D and 3D Hall MHD simulations
Authors: Montagud-Camps Victor , Hellinger Petr , Verdini Andrea , Landi Simone , Papini Emanuele , Franci Luca , Matteini Lorenzo
Published: March 2021

Turbulence in the solar wind is developed along a vast range of scales, generally under weakly compressible and strong magnetic field plasma conditions.
The effects of weakly and moderate compressibility (Mach ≤1) and turbulence anisotropy on the energy transfer rate are investigated at MHD and Hall MHD scales. For this purpose, the results of two and three-dimensional compressible Hall MHD simulations are analyzed using a new form of the Karman-Howarth-Monin (KHM) equations that accounts for compressible effects down to Hall MHD scales.
The KHM are dynamic equations directly derived from the basic fluid equations that describe the plasma, such as the Hall MHD equations. They provide a relation between the two-point cross-correlations in real space or II-order structure functions, the III-order structure functions and the energy cascade rate of turbulence. These relations depend upon turbulence anisotropy. The effects of compressibility and the Hall term on anisotropy and the estimation of the energy cascade rate via the KHM equations are discussed.
Systemic soil modelling and the evaluation of functions
Authors: Weller Ulrich , König Sara , Betancur-Corredor Bibiana , Lang Birgit , Ließ Mareike , Mayer Stefanie , Reitz Thomas , Stößel Bastian , Vogel Hans-Jörg , Wiesmeier Martin , Wollschläger Ute
Published: March 2021

We developed an integrated model of soil processes – the Bodium – that enables us to predict possible changes in soil functions under varying agricultural management and climatic change.

The model combines current knowledge on soil processes by integrating state-of-the-art modules on plant growth, root development, soil carbon and matter turnover with new concepts with respect to soil hydrology and soil structure dynamics. The model domain is at profile scale, with 1D nodes of variable thickness and weight. It is tested with long-term field experiments to ensure a consistent output of the combined modules. The model is site-specific and works with different soil types and climates (weather scenarios).

The output can be interpreted towards a broad spectrum of soil functions. Plant production and nutrient balances can be determined directly. The same is possible for water dynamics, with potential surface runoff (as infiltration surplus), storage and percolation together with travel time and groundwater recharge. In addition, nitrate losses are calculated, and the travel time distribution can help with the evaluation of pesticide percolation risk. To evaluate the habitat for biological activity, the activity is calculated in terms of carbon turnover, and the state variables carbon availability, water, air and temperature for the are accessible. Also, for macrofauna the earthworm activity is included. The comparison of scenario runs can be evaluated quantitatively in terms of potential developments of soil functions.

The model is work in progress. Further modules that will be implemented are pH dynamics, more explicit microbial activity, and a more complete set of effects of agricultural management on soil structure are integrated.
Foreshock compressive structure-magnetosheath jet coupling in a global hybrid-Vlasov simulation
Authors: Suni Jonas , Palmroth Minna , Turc Lucile , Battarbee Markus , Johlander Andreas , Tarvus Vertti , Alho Markku , Dubart Maxime , Ganse Urs , Grandin Maxime , Papadakis Konstantinos , Pfau-Kempf Yann
Published: March 2021

Magnetosheath jets are a class of phenomena usually defined as pulses of high dynamic pressure in the magnetosheath, but the details of their origins are currently unclear. Many theories on the origin of magnetosheath jets have been developed, such as bow shock rippling and foreshock structures. The usefulness of spacecraft data in studying some of them is limited, due to the transient and localised nature of jets. We use the 5D global hybrid-Vlasov simulation Vlasiator in a statistical study to investigate the relationship between compressive structures in the foreshock and magnetosheath jets. Foreshock compressive structures and magnetosheath jets are identified and their evolution over time is tracked. We find that up to 75% of magnetosheath jets forming at the bow shock are associated with foreshock compressive structures impacting the bow shock at the same location. Furthermore, magnetosheath jets that are associated with foreshock compressive structures penetrate deeper into the magnetosheath than jets that are not associated with foreshock compressive structures.
Deficit Irrigation of Cool and Warm Season Turfgrass Varieties under Sprinkler Irrigation Method
Authors: Orta Abdül Halim , Kuyumcu Seray
Published: March 2021

The aim of this study is to determine the effects of deficit irrigation applications at different levels on the cool-season and warm-season turfgrass species irrigated by sprinkler irrigation. Field experiments were conducted in the Agricultural Production and Research Center (TURAM) of Silivri Municipality in Gümüşyaka District located between the boundaries of Tekirdağ and Istanbul - TURKEY, at growing season 2019. In this research, two different turfgrass types (K: Cool season turfgrass and B: Warm season turfgrass), at three different irrigation threshold were examined in split-plots in randomized blocks design with three replications. Cool season turfgrass types lost its green colour completely after July due to the dry and hot summer season and the total amount of irrigation water applied in different irrigation strategies varied between 101.4 mm - 303.9 mm, seasonal evapotranspiration values varied between 217.7 mm - 391.5 mm, and daily evapotranspiration values varied between 2.4 mm/day - 4.3 mm/day. As for warm-season turfgrass types that managed to stay alive and kept its green colour throughout whole summer period; the same values varied between 203,6 mm - 591,6 mm; 328.4 mm - 593.9 mm; and 2,1 mm/day – 3,9 mm/day, respectively. In the 3-month period (May-June-July) in which both types of grass could survive, the seasonal evapotranspiration values were 11% more in the cool season turfgrass than that of warm season turfgrass. When daily evapotranspiration values were compared, it was observed that it was 10-14% more in cool-season turfgrass than in warm-season turfgrass. Average CWSI values calculated for different irrigation treatments were 0,57-0,66 for cool-season turf, 0,52-0,66 for warm-season turf besides, average CWSI values before irrigation application were 0,68-0,79 for cool-season turf, 0,69-0,79 for warm-season turf. Changes in the vegetation height, fresh yield, dry yield, plant density, color, and quality properties were monitored depending on the irrigation levels. When factors such as the amount of irrigation water applied, water-use and irrigation water-use efficiency, and quality parameters are evaluated together; none of treatments were adequate to keep cool-seasons varieties green after July. In the warm season turfgrass variety, although all irrigation levels provide the desired level for plant growth and quality, S2 treatment has been suggested when all parameters mentioned above are taken into consideration. Besides, Jensen Haise method (JH) was chosen as the best equation when reference evapotranspiration estimation methods were compared for both types of turf and crop coefficient (kc) curves have been prepared for both turfgrass species.
Ice sheet scale subglacial meltwater conduit dimensions and processes: insights from 3D morphometry of a large sample of eskers
Authors: Storrar Robert , Jones Andrew , Butcher Frances , Dewald Nico , Clark Chris , Delaney Cathy , Evans David , Lewington Emma , Livingstone Stephen , Stokes Chris
Published: March 2021

Meltwater exerts an important influence on ice sheet dynamics and has attracted an increasing amount of attention over the last 20 years. However, the active subglacial environment remains difficult to study mainly due to its inaccessibility. Understanding of the dimensions, pattern, and extent of subglacial meltwater conduits at the ice sheet scale is limited to relatively sparse observations. We address this gap by using the geomorphological record of Quaternary ice sheets as a proxy to quantify the dimensions and pattern of subglacial conduits at the ice sheet scale. We present the results of a high-resolution (2 m), large sample (n>50,000) study of three-dimensional esker morphometry at sample locations in SW Finland and Nunavut, Canada. Detailed mapping of esker crestlines and outlines permits the quantification of a number of parameters, including: length, width, height, cross-sectional area, volume, sinuosity, cross-sectional symmetry, and uphill/downhill trends. Whilst the dimensions of eskers reflect depositional processes as well as simply the size of the parent conduit, they nevertheless offer a powerful tool for understanding the size and shape of meltwater conduits and the configuration of subglacial drainage systems across large areas (entire ice sheets), and over long periods of time (from years to thousands of years) in both high spatial and temporal resolution. The results may be used to: (1) inform numerical models of subglacial meltwater drainage, (2) inform process models of esker formation, and (3) provide a dataset of esker morphometry against which other features may be compared (e.g. sinuous ridges on Mars).