bluuebunny/crossref_metadata_2025 huggingface dataset:
What limits deep water uptake by deep-rooted crops?
Authors: Rasmussen Camilla , Rosenqvist Eva , Liu Fulai , Bodin Dresbøll Dorte , Thorup-Kristensen Kristian , Javaux Mathieu
Published: March 2020

Minimizing water limitation during growth of agricultural crops is crucial to unlocking full yield potentials. Crop yield losses vary according to timing and severity of water limitations, but even short-term droughts can be a major cause of yield losses. While the potential influence of deep roots on water uptake has been highlighted numerous times, the actual contribution of deep roots to water uptake is yet to be revealed. The objective of this study is to get an understanding of what limits deep water uptake by deep-rooted crops under topsoil water limitations.

We found that deep-rooted crops experience water limitations despite access to water stored in the deep soil and we hypothesize that deep water uptake by deep-rooted crops is limited by 1) the hydraulic conductivity of the deeper part of the root zone, arising from limited root length density in combination with the hydraulic resistance of the roots or 2) by a hormonal response arising from the plant sensing dry conditions in the shallow soil leading to stomata closure, to conserve water. The two hypotheses can of course not be valid simultaneously, but both might be valid under certain conditions, at certain times or for certain species.

In a large-scale semi-field setup, we grow oil seed rape and by combining measures of root development, root hydraulic conductivity, transpiration, stomatal conductance, ABA concentrations and soil water content from a large scale semi-field setup with a mechanistic 3-D root-soil modelling approach (R-SWMS), we are able to us distinguish various scenarios and to evaluate what limits deep water uptake.
Low Cost Sensor Node for Monitoring River Floods
Authors: Skoubris Evangelos , Hloupis George
Published: March 2020

River floods occupy a respectable percentage among all natural disasters, are presenting high risk, and usually cause great damage. Important tools in managing and preventing river floods are the Early Warning Systems (EWS), which are usually consisted both by a hardware infrastructure (sensors, communication network) and a relevant software infrastructure (data logging, signal processing, modeling, risk detection).

In the current work we are presenting preliminary results from a novel, low-cost and low-power hardware system, part of a EWS aimed for river floods. The system consists of multiple sensing nodes, each to be strategically positioned at certain points along the route of river Evros, Greece. Each sensing node will bear a low-cost and high-quality ultrasonic water level sensor, along with an embedded microcomputer to control its functionality. An additional novelty of the proposed work is the design and utilization of a private low-power wide-area wireless network (LPWAN), taking advantage of IoT technologies and especially the LoRaWAN implementation. This way, the proposed system will have even lower power demands, together with greater expandability by allowing many nodes to be simultaneously connected and measuring, and having the ability to utilize crowd-sensing techniques. The power supply is battery based and autonomously recharged with the aid of small solar panel. Each node will measure the water level of the river, and upload the data to a cloud server at variable time intervals, depending on the actual water level variation and the system’s power consumption optimization.

Future upgrades of the system will involve extra sensors, allowing the nodes to measure water quality parameters i.e. suspended solids, pH, etc. Although of secondary importance, these parameters might prove to be important in the development of the risk detection and alarm issuing algorithms.
Assessing the effect of soil crack dynamics on hydraulic properties of agricultural soil from reduced tillage and conventional tillage fields, Wallonia-Belgium
Authors: Ralaizafisoloarivony Njaka Andriamanantena
Published: March 2020

Crack formation and development have been a general concern in agricultural science. Cracks contribute to soil aeration, aggregate formation, and easy root penetration. However, cracks facilitated water evaporation, accelerated soil desiccation, allowed deep infiltration of pesticides/pollutants through preferential flow, and polluted the shallow water-table in Belgium.  From many years, farmers reported the presence of cracks in their field; however, few studies investigated cracks formation from agricultural soil under different cultural practices. This research investigated the effect of cultural practices (conventional and reduced tillage) on crack formation and on soil hydraulic properties.

 

Soils were collected right from the agricultural field and processed (in laboratory) under evaporation experiment on a small drying chamber. Ceramic-IR-emitter heated the chamber while sensors (PT1000, DHT22) measured the temperature and relative humidity. Digital camera took photos of the soil surface at 30min interval. Balance and tensiometer commanded by a datalogger (CR800), recorded the soil hydraulic properties (water suction, water retention, evaporation rate etc.). Cracks were monitored and extracted using image analysis performed by ImageJ and PCAS software. The soil water retention curve (SWRC) was fitted with the bimodal models of Durner (1994) and Seki (2007). The output data were analysed statistically using appropriate software. Three treatments were considered including: disturbed soil, conventional tillage and reduced tillage.  

 

The results showed higher cracks formation on disturbed soil > reduced-tillage > conventional-tillage due to loose of soil cohesion, soil organic content, soil aggregation, biological activities, and soil porosity. Crack formed at low matrix suction for reduce tillage, but higher tension for conventional tillage and disturbed soil. The soil evaporation rate was also greater in reduced-tillage > conventional tillage > disturbed soil. The effect of cracks affected the SWRC for reduced tillage and disturbed soil. The result suspected the presence of pre-installing (or micro)cracks in the reduced-tillage samples. Future study is needed to assess the presence of pre-(micro)-cracks in soil using X-ray microtomography. 
Mineralogical and morphological characterization of a suspected lunar silicic construct: The Wolf crater
Authors: Moitra Himela , Pathak Sumit , Chauhan Mamta , Gupta Saibal , Bhattacharya Satadru
Published: March 2020

The Wolf crater is an irregularly shaped crater situated within the central part of Mare Nubium in the southern hemisphere on the lunar near side (16.573°W, 22.904°S). With an approximate diameter of about 25 km, this crater has been recently suspected to be a lunar silicic construct, hinting at a felsic composition that is more silicic than pure, immature anorthite. These suspicions have mainly been triggered by the high thorium anomaly in this region, and Christiansen Feature (CF) and Concavity Index (CI) mapping using Diviner multispectral data from the Lunar Reconnaissance Orbiter (LRO) mission. Many areas in the Wolf crater show CF values lower than 7.84 µm (CF for pure, immature anorthite). This study adopts a more holistic approach by studying the mineralogical composition and morphology of this crater complex using Moon Mineralogy Mapper (M3) data for mineralogical analysis and LROC WAC (wide angle camera) and NAC (narrow angle camera) data for morphological analysis. The whole complex can be divided into two parts- highland massif and mare basalt regions. CSFD analyses show that the outer part of the massif is older than the mare basalt, whereas the inner part have relatively younger surfaces. Analysis of the M3 data reveals the presence of pyroxene exposures on the massif as well as the mare basalt. However, their compositions are distinctly different, the massif pyroxenes being low-Ca pyroxene while the mare pyroxenes are High-Ca pyroxenes in composition. It can be inferred that the pyroxene exposures on the massif are not related to any ejecta deposits from the mare basalts. The highly silicic compositions implied by the CF and CI maps are limited to only certain parts of the massif, indicating a compositional heterogeneity in the massif region as well. Morphologically, the highland massif shows an extremely knobby structure which surrounds the mare basalt in a topographically depressed central part. The massif is discontinuous and the mare-highland boundary is very irregular, suggesting that the central depression is not of an impact-related origin. Extensional deformation features near the mare-highland boundaries also support this. In some parts, dome like features can be identified, with fresh rock fragments being visible on the surface. The rock fragments seem to be of two different tones- one very bright tone, and another comparatively darker tone. These rock fragments cannot be related to any nearby cratering activity, and they seem to be embedded in their locations. Pyroclastic deposits can also be identified around some of these domes, by their characteristic low albedo and smooth appearance. Overall, the Wolf crater complex shows signatures of non-mare volcanic activity and can be of non-impact related volcanic origin.
Simulations of VLBI observations to satellites enabling co-location in space
Authors: Mammadaliyev Nicat , Schreiner Patrick , Glaser Susanne , Neumayer Karl Hans , Koenig Rolf , Heinkelmann Robert , Schuh Harald
Published: March 2020

The exceptional situation of simultaneously observing a dedicated near-Earth orbiting satellite via the four main space geodetic techniques opens the unique opportunity to investigate the additional benefits on the realization of global terrestrial reference frame using co-location in space. Applying co-location in space requires a precise orbit determination (POD) of dedicated satellites for all techniques. In this regard, current VLBI infrastructure is extended by the observation to satellites and the impact of such observation concept on the VLBI estimates is assessed. Thus the main geodetic products including the terrestrial reference frame are investigated within the GGOS-SIM-II project. In this study, the potential influence of orbital errors on the estimates and capability of VLBI observations to satellites within the POD are investigated for different scenarios with varying networks, observation time and measurement noise.  
A method for the assessment of forest regrowth site index based on Earth observations and modelling
Authors: Zharko Vasily , Bartalev Sergey , Bogodukhov Mikhail
Published: March 2020

Presented is a method for the estimation of a productivity class/site index of the forest regrowth after stand replacement natural and human induced disturbances. The method uses Global Forest Change project data on spatial distribution of forest loss sites (including the information about the date of the disturbance) with a 30 m resolution based on Landsat data. Joint analysis of this data resampled to 100 m spatial resolution together with a Russian Land Cover map for 2016 developed based on 100 m PROBA-V data is used to identify reforestation sites and to determine the forest type. Based on this information an appropriate forest growth model is chosen to simulate forest characteristics' dynamics for different site indexes. Finally information on forest characteristics from satellite data-based products is compared to the modeling results for the forest age, computed as a difference between the date of the disturbance and the date of the satellite data product. Reforestation site is assigned a productivity class that yields the best consistency between modeling results and existing satellite data products information.

Application of the presented method was tested over the European part of Russia using a 100 m global growing stock volume (GSV) map developed within Globbiomass project and lidar vegetation canopy height measurements from ICESat-2/ATLAS system (ATL08 data product). It was found that ICESat-2/ATLAS data is better suited for the proposed approach.

Presented method is aimed at the development of a reference dataset on forest parameters since obtained information on forest type, age and site index together can be used to estimate other crucial characteristics, including GSV, mean height, mean stem diameter, basal area, productivity, growth and mortality parameters, using the appropriate model. It is also worth mentioning that proposed approach allows estimation of characteristics of young forests which are rarely represented in the field survey-based reference datasets.

This work was supported by the Russian Science Foundation [grant number 19-77-30015]. Data processing and analysis was carried out using resources of the Centre for collective use ‘IKI-Monitoring’ developed by the Space Research Institute of the Russian Academy of Sciences.
Sea ice representation in CMIP6 simulations with EC-Earth3-Veg
Authors: Koenigk Torben , Dekker Evelien
Published: March 2020

In this study, we compare the sea ice in ensembles of historical and future simulations with EC-Earth3-Veg to the sea ice of the NSIDC and OSA-SAF satellite data sets. The EC-Earth3-Veg Arctic sea ice extent generally matches well to the observational data sets, and the trend over 1980-2014 is captured correctly. Interestingly, the summer Arctic sea ice area minimum occurs already in August in the model. Mainly east of Greenland, sea ice area is overestimated. In summer, Arctic sea ice is too thick compared to PIOMAS. In March, sea ice thickness is slightly overestimated in the Central Arctic but in the Bering and Kara Seas, the ice thickness is lower than in PIOMAS.

While the general picture of Arctic sea ice looks good, EC-Earth suffers from a warm bias in the Southern Ocean. This is also reflected by a substantial underestimation of sea ice area in the Antarctic.

Different ensemble members of the future scenario projections of sea ice show a large range of the date of first year with a minimum ice area below 1 million square kilometers in the Arctic. The year varies between 2024 and 2056. Interestingly, this range does not differ very much with the emission scenario and even under the low emission scenario SSP1-1.9 summer Arctic sea ice almost totally disappears.
Seismogenic source model of the 2019 Mw 5.9 East-Azerbaijan earthquake (NW Iran) through Sentinel-1 DInSAR measurements
Authors: Valerio Emanuela , Casu Francesco , Convertito Vincenzo , De Luca Claudio , De Novellis Vincenzo , Manunta Michele , Manzo Mariarosaria , Monterroso Fernando , Lanari Riccardo
Published: March 2020

On 7 November 2019 (22:47 UTC) a Mw 5.9 earthquake struck the East-Azerbaijan region, in the north-western Iran, about 100 km east of Tabriz, the fourth largest city of Iran with a population of over two million. This seismic event caused both widespread damage to the surrounding villages and casualties, killing about 5 people and injuring hundreds. The occurrence of this earthquake is related to the main geodynamic regime controlled by the oblique Arabia-Eurasia convergence and, in particular, this event is inserted in the tectonic context of the East-Azerbaijan Plateau, a complex mountain belt that contains internal major fold-and-thrust belts.

In this work, we first generate the coseismic deformation maps by applying the Differential Synthetic Aperture Radar Interferometry (DInSAR) technique to SAR data collected along ascending and descending orbits by the Sentinel-1 constellation of the European Copernicus Programme. Then, we invert them through analytical modeling in order to better constrain the geometry and characteristics of the main source. The retrieved fault model revealed a shallow seismic source approximately NE–SW-striking and characterized by a left-lateral strike-slip, southeast-dipping faulting mechanism. Our retrieved solution reveals a new minor fault never mapped in geological maps before, whose kinematics is compatible with that of the surrounding structures and with the local and regional stress states. Moreover, we also use the preferred fault model to calculate the Coulomb Failure Function at the nearby receiver faults; taking into account the surrounding geological structures reported in literature, we show that all the considered receiver faults have been positively stressed by the main event. This is also confirmed by the distribution of the aftershocks that occurred near the considered faults. The analysis of the earthquake nucleated along these left-lateral strike-slip minor fault is essential to improve our knowledge of the East-Azerbaijan Plateau; therefore, further studies are required to evaluate their role in seismic hazard definition of northwest of Iran, in order to help in the mitigation of the seismic hazard in seismogenic regions unprepared for the occurrence of seismic events.

This work is supported by: the 2019-2021 IREA-CNR and Italian Civil Protection Department agreement, H2020 EPOS-SP (GA 871121), ENVRI-FAIR (GA 824068) projects, and the I-AMICA (PONa3_00363) project.
Field characterization of the negatively buoyant inflow of the Rhône River into Lake Geneva
Authors: Thorez Stan , Lemmin Ulrich , Barry Andrew , Blanckaert Koen
Published: March 2020

River inflows have a major influence on lake and reservoir water quality through their input of momentum, heat, oxygen, sediment, nutrients and contaminants. The fate of these components is controlled by the hydrodynamic processes at the interface between the inflowing river and the receiving lake or reservoir. The inflow can be positively buoyant, leading to a near surface inflow current (overflow), or negatively buoyant, causing it to plunge and form a gravity-driven current near the bed (density current) and/or intermediate current (interflow). In the case of a plunging inflow, the plunging process provides upstream boundary conditions for density currents, which can continue for significant distances along the lakebed. It is therefore important to understand the mixing processes involving entrainment of ambient water into the plunging flow. The hydrodynamics of the plunging process are still poorly understood, especially in laterally unconfined configurations.

Field measurements of a laterally unconfined plunging flow of the Rhône River into Lake Geneva are presented. A vessel-mounted ADCP was used to measure the three-dimensional velocity field of the plunge region. Remote sensing images of the lake surface in the plunge region were captured with a static camera system set up on a nearby mountain overlooking the inflow. Additionally, a mobile camera system attached to a balloon was operated above the inflow to capture high-resolution videos of the inflow. Both camera systems were equipped with RGB and IR cameras. The ADCP measurements and remote sensing images were combined to detect mixing processes in three dimensions.

The remote sensing images show that the incoming river flow forms a distinct plume of sediment-rich water with a triangular shape leading away from the river mouth in downstream direction towards a sharp tip. Horizontal vortical structures visible at the surface, range from larger gyres, over vortex shedding and dipole formation downstream of the plume, to smaller scale structures such as Kelvin-Helmholtz instabilities at the plume edges. The ADCP measurements show the presence of vertical secondary circulation cells in transects perpendicular and parallel to the plume centerline. In addition, intermittent ‘boils’ of sediment rich water up to more than 200 meter downstream of the plume were observed in the images.
Automated estimation of englacial radar velocity from zero offset data; implications for glacier bed topography retrieval
Authors: Delf Richard , Bingham Robert G , Curtis Andrew , Singh Satyan , Schwarz Benjamin , Giannopoulos Antonios
Published: March 2020

Ground Penetrating Radar (GPR) is widely used on polythermal and temperate glaciers to sound bed topography and investigate the hydrothermal conditions through detection of englacial radar scattering. Water held within micro- and macro-scale pores and ice grain boundaries in ice at the pressure melting point influences the velocity of radar propagation on the scale of the wavelength, and can result in the occurrence of pronounced diffraction patterns in the data. Methods to investigate the water content distribution quantitatively within temperate ice often require the use of multi-offset common mid-point or common source-point survey techniques, which are logistically challenging and expensive. As a result, bed topography estimation is often undertaken using a constant velocity, and, because lateral variations in the the velocity field are unaccounted for, errors in topography are likely.

Here, we present an automated workflow to estimate an englacial radar velocity field from zero offset data and apply the algorithm to GPR data collected on Von Postbreen, a polythermal glacier in Svalbard, using a 25 MHz zero-offset GPR system. We first extract the diffracted wavefield using local coherent stacking to remove scatter and enhance diffractions. We then use the focusing metric of negative entropy to deduce a local migration velocity field from constant-velocity migration panels and produce a glacier-wide model of local (interval) radar velocity. We show that this velocity field is successful in differentiating between areas of cold and temperate ice and can detect lateral variations in radar velocity close to the glacier bed. The effects of this velocity field in both migration and depth-conversion of the bed reflection are shown to result in consistently lower ice depths across the glacier, indicating that diffraction focusing and velocity estimation are crucial in retrieving correct bed topography in the presence of temperate ice.
A Quality-Controlled Global Sub-daily Precipitation Dataset and Sub-daily Precipitation Indices
Authors: Fowler Hayley , Lewis Liz , Blenkinsop Stephen , Pritchard David , Guerreiro Selma , Villalobos Herrera Roberto , Becker Andreas
Published: March 2020

Extremes of precipitation can cause flooding and droughts which can lead to substantial damages to infrastructure and ecosystems and can result in loss of life. It is still uncertain how hydrological extremes will change with global warming as we do not fully understand the processes that cause extreme precipitation under current climate variability. Progress has been limited so far in this area due to the lack of data available to researchers. The INTENSE project, part of the with the World Climate Research Programme (WCRP)'s Grand Challenge on 'Understanding and Predicting Weather and Climate Extremes', has used a novel and fully-integrated data-modelling approach to provide a step-change in our understanding of the nature and drivers of global sub-daily precipitation extremes and change on societally relevant timescales.

The first step towards achieving this was to construct a new global sub-daily precipitation dataset. The dataset contains hourly rainfall data from ~25,000 gauges across >200 territories from a wide range of sources. A rigorous, flexible quality-control algorithm has been developed to ensure that the data collected is as accurate as possible. The QC methodology combines a number of checks against neighbouring gauges, known biases and errors, and thresholds based on the Expert Team on Climate Change Detection and Indices (ETCCDI) Climate Change Indices.  An open source version of the QC software will set a new standard for verifying sub-daily precipitation data.

A set of global sub-daily precipitation indices have also been produced (and will be made freely available later this year) based upon stakeholder recommendations including indices that describe maximum rainfall totals and timing, the intensity, duration and frequency of storms, frequency of storms above specific thresholds and information about the diurnal cycle. The talk will discuss the major findings from the production of these new global sub-daily precipitation indices.
Flood proofing measures cost-efficiency analysis for hydraulic risk mitigation in an urbanized riverine area
Authors: Ventimiglia Ugo , Aronica Giuseppe Tito , Candela Angela
Published: March 2020

Flood proofing measures cost-efficiency analysis for hydraulic risk mitigation in an urbanized riverine area

Ugo Ventimiglia 2, Angela Candela 1, Giuseppe Tito Aronica 2

1 Department of Engineering, University of Palermo, Palermo, Italy

2 Department of Engineering, University of Messina, Messina, Italy

Use of non-structural measures for flood risk mitigation is often more economically accessible, easy to implement and are highly effective, but only if this use is supported by a detailed hydraulic analysis necessary for a correct design. Among the non-structural measures, a progressive and increasingly accentuated importance is attributed to flood proofing interventions, especially in view of the pursuit of risk resilience objectives. Flood proofing interventions are normally classified in two main types: dry flood proofing and wet flood proofing. One measure of dry flood proofing is the shielding, which consists in the use of flood barriers, which can be installed at the entrance of the buildings or at a certain distance from them in order to avoid contact with the houses and deviate the flow of water. A similar type of interventions also avoids inducing sensations of false security (levee effect) in the exposed population and therefore contributes to increasing their resilience. In the context of risk management, resilience is the intrinsic ability of a system to modify its functioning before, during and following a change or an event, so as to be able to continue the necessary operations both under expected conditions and under unexpected conditions. Aim of work presented here is to determine an optimal combination and choice between different types of structural and non-structural measures, through the development of a methodology for assessing the real effectiveness of different measures, through a cost-benefit analysis (CBA) starting from the estimate of direct flood damage. The application of the CBA, to the real case study of the Mela river, located in north-eastern Sicily, which suffered a flooding in October 2015, supported by the determination of the real damages after the flood and the modelling of the same for the alternative scenario, has returned results significant capable of affirming the ability to reduce or avoid part of the damage.

https://drive.google.com/file/d/14dlP9Nt0A8bc4UUrv8az8pxIHp8bZ6GV/view?usp=sharing

 
Convergences and divergences between data-driven GPP estimates and high-resolution SIF measurements across vegetation and climatic gradients
Authors: Pickering Mark , Cescatti Alessandro , Duveiller Gregory
Published: March 2020

Sun-induced chlorophyll fluorescence (SIF) retrieved from satellites has shown potential as a remote sensing proxy for gross primary productivity (GPP). However, current studies have generally been limited by the spatial resolution of datasets with a sufficiently long archive. For example, while available since 2007, the commonly used GOME-2 SIF data has a spatial resolution in the order of 0.5° (~50km), too coarse to effectively separate the competing effects of different types of vegetation from the overall ecosystem dynamics, or to draw general conclusions relevant to the land cover of a region. While finer SIF retrievals are becoming available, such as from the TROPOMI instrument on-board of the Sentinal-5P platform, several years will be needed before their archives reach a sufficient temporal depth.

 

Using GOME-2 SIF retrievals, downscaled to a resolution of 0.05° (~5km) via a proven methodology [1], comparisons are made with the data-driven FLUXCOM GPP dataset and divergences and convergences explored to see where high-resolution SIF can enhance our understanding of GPP. This includes an exploration of the spatial and temporal relationships between estimates of GPP and SIF at a global scale. The high resolution of the SIF data allows the relationships to be broken down by plant functional type (PFT) for separate climate zones, thus enabling a confrontation between FLUXCOM GPP and SIF at fine granularity and eventually a future integration of SIF in the estimation of data-driven GPP products.

 

Whilst a linear relationship is generally observed between SIF and GPP in all vegetation categories, areas of non-linearity suggest where SIF could potentially provide more information about ecosystem dynamics that are not represented in the GPP dataset. For example some vegetation types experience saturation in the seasonal GPP measurements (likely driven by the saturation of the fraction of absorbed PAR), that are not emerging from the SIF signal. In addition, in highly productive ecosystems like tropical rainforests, a wide range of spatio-temporal variation in SIF is observed, while only a considerably smaller variability is reproduced in the modelled GPP. Further studies are conducted on how SIF and GPP behave differently in anomalies of air temperature and soil moisture. Overall, the study suggests there is room to improve global land-climate models by incorporating information from SIF.

 

 

[1] Duveiller, G., Filipponi, F., Walther, S., Köhler, P., Frankenberg, C., Guanter, L., and Cescatti, A.: A spatially downscaled sun-induced fluorescence global product for enhanced monitoring of vegetation productivity, Earth Syst. Sci. Data Discuss., , in review, 2019.
Environmental impacts of diamond mining in the Democratic Republic of Congo
Authors: Galli Nikolas , Chiarelli Davide Danilo , D'Angelo Manuel , Rulli Maria Cristina
Published: March 2020

The mining industry of the Democratic Republic of the Congo represents the most important sector of the country’s economy being DRC the second-largest diamond-producer in the world. By far the largest diamond-mines in the DRC are located in southern Katanga province.

There are many types of mining techniques and alluvial mining is the one that usually takes place in DRC.

Alluvial diamonds are diamonds that have been removed from the primary source (Kimberlite) by natural erosion, and eventually deposited in a new environment such as a river beds and floodplains. This type of mining leads obviously to a number of impacts: deforestation, river pollution, water resources exploitation, unhealthy, unregulated and sometimes dangerous environments in which diggers work.. All these effects are strictly related and difficult to evaluate since the DRC is in a situation of institutional chaos and humanitarian crisis due to high rate of malnutrition.

Here we analyze the impact of diamond mining industry on natural resources, and population in Democratic Republic of Congo. To this end using spatial and temporal high resolution data we evaluate the tree cover losses and the water resources use associated with mining activity from 2000 to 2018 and using a dynamic and spatially distributed crop water model we provide alternative use of natural resources (i.e. land and water) presently used for mining so assessing the likelihood to contrast malnourishment.
Effects of management on soil organic carbon and structural stability in olive grove toposequences in Mediterranean areas.
Authors: González-Rosado Manuel , Aguilera Huertas Jesús , Lozano-García Beatriz , Parras-Alcántara Luis
Published: March 2020

Carbon sequestration in agricultural soils has been defined as a positive strategy to mitigate the climate change effects. To implement this strategy, it is necessary to reduce the soil physical disturbances that encourage its degradation. It is therefore essential to analyze the consequences that conventional tillage practices have on agrosystems as a first step towards developing sustainable management practices that are in line with strategies to combat climate change. In order to evaluate the conventional tillage impact in olive groves, a toposequence was carried out where three profiles of 50 cm depth each were opened in three topographical positions: summit, backslope and toeslope. The physical and chemical soil properties were analyzed, including soil organic carbon (SOC) and mean weight diameter (MWD) of the aggregates, which showed a plot scale low SOC levels and low MWD being subject to erosive processes which negatively impacts on its SOC storage capacity.
Relationships between aboveground and belowground biomass stock – a case study from mountain area temperate forests in the northern Carpathians
Authors: Zielonka Anna , Drewnik Marek , Musielok Łukasz , Struzik Dariusz , Smułek Grzegorz , Ostapowicz Katarzyna
Published: March 2020

The content of organic carbon in forest is partitioned between organic carbon accumulated in aboveground biomass (AGB) and belowground biomass (BGB) and is impacted by various natural and human factors. Growing interest in estimates of global biomass (and organic carbon) pools require research on a local scale in the context of potential environmental factors affecting their spatial distribution. Therefore, our aim of the research was to both derive and evaluate the relationship between aboveground biomass consisting mainly of European beech (Fagus sylvatica L.), spruce (Picea abies L. Karst) and fir (Abies alba Mill.) and BGB with particular emphasis on fine root biomass (FRB) as the most dynamic part of the root system and soil organic matter stock (SOM). Data were collected at 32 national forest inventory plots in mountainous temperate forests with different history of forest management located across the Carpathian range in Poland. All study plots were characterized with very similar soil properties (Cambisols). Moreover, numerous environmental factors affecting biomass distribution were taken under consideration. The largest aboveground biomass occurred in beech-dominated stands (~40 Mg ha-1 to over ~ 440 Mg ha-1). In the sampled depth layer (0-40 cm) the highest SOM stock was identified in soils under beech-dominated stands (median ~158 Mg ha-1). FRB was the highest under fir-dominated stands (median ~3.7 Mg ha-1). The amount of SOM and FRB differed also in the analyzed soil depth layers (10 cm interval up to 40 cm) reaching mostly the highest values at soil depths of 0-10 cm. The highest amount of biomass (both aboveground and the belowground) has been identified in beech-dominated forests. We examined relationships between AGB, FRB, and SOM, but were not able to identify clear significant correlations based only on vegetation parameters. Derived results illustrate the complexity of identifying significant relationships between aboveground and belowground biomass stocks. Employing the same models may be an erroneous strategy for different study sites because of local environmental factors that strongly determine aboveground and belowground biomass stock. Accordingly, creating biomass and carbon models at larger scales in northern Carpathians based on forest aboveground data may cause an over- or underestimation due to the significant impact of both abiotic and biotic factors. 

 

This research study was funded by the Polish National Science Centre (RS4FOR Project: Forest change detection and monitoring using passive and active remote sensing data (No. 2015/19/B/ST10/02127) and via Project No. UJ/IGiGP/K/DSC/004779.
Evapotranspiration assessments from drone-based thermography - a method comparison in an oil palm plantation and a look ahead
Authors: Röll Alexander , Ellsäßer Florian , Stiegler Christian , June Tania , Hendrayanto Hendrayanto , Knohl Alexander , Hölscher Dirk
Published: March 2020

Evapotranspiration (ET) is a key flux in hydrological cycles; it is affected by both climate and land-use change. A recent study across 42 study sites in four land-use types in lowland Sumatra (Indonesia) reported that local and regional transpiration are on the rebound due to the high water use and continuing expansion of oil palm plantations. Conventional ET assessment methods such as satellite-based thermography or the eddy covariance (EC) technique lack the high spatial resolution and spatial replicability, respectively, that are required for ET assessments in dynamic and heterogeneous, mosaic-like landscapes. For such assessments of ET, near-surface airborne thermography offers new opportunities for studies with high numbers of spatial replicates and in a fine spatial resolution. In our study, we tested drone-based thermography and the subsequent application of three energy balance models (DATTUTDUT, TSEB-PT, DTD) using the widely accepted EC technique as a reference method. The study site was a mature oil palm plantation in lowland Sumatra. For 61 flight missions, latent heat flux estimates of the DATTUTDUT model with measured net radiation agreed well with eddy covariance measurements (r²=0.85; MAE=47; RMSE=60) across variable weather conditions and daytimes. Confidence intervals for slope and intercept of a Deming regression suggest no difference between drone-based and eddy covariance method, thus indicating interchangeability. TSEB-PT and DTD yielded agreeable results, but all three models are highly sensitive to the configuration in which net radiation is assessed. Overall, we conclude that drone-based thermography with energy-balance modeling is a reliable method complementing available methods for ET studies. It offers promising, additional opportunities for fine grain and spatially explicit studies. Further steps in the near future will include the testing and if necessary calibrating of the method across different biomes as well as ecological applications.
Mechanism of air entry during collapse of saturated and unsaturated columns of transparent granular soil
Authors: Taylor-Noonan Alexander , Arpin Natalie , Cabrera Miguel , Siemens Greg , Take W Andrew
Published: March 2020

The granular column collapse experiment, which consists of the rapid removal of lateral support to a column of granular material, is an important benchmark case for the physical and numerical study of transitional mass flows. While other researchers have focussed on the link between the aspect ratio of the column to mobility of the flow, these experiments are also an important platform to evaluate frameworks for triggering of slope failures.

 

Critical state soil mechanics centers around the theory that initially dense soils will dilate, and initially loose soils will contract upon shearing. If the soil is sheared at a rate which exceeds the rate which fluids can be expelled or drawn into the pore space between particles, the shearing is considered to be occuring at constant volume and termed “undrained”. This state is associated with a rise in pore fluid pressure and a reduction in intergranular normal effective stress. The authors have conducted experiments varying the time scales of the volume change and dissipation processes. In these experiments, a novel transparent soil mixture comprised of quartz and mineral oil was utilized to visualize the saturation regime of soils during the granular column collapse experiment. Particular attention was paid to triggering mechanisms and the transition between the metastable state and avalanche regimes. The transparent material allowed visual confirmation of the volume change during shearing and important insights were gained into the role of the unsaturated soil condition in temporary strength. These observations have implications beyond the column collapse experiment, including the initiation of debris flow experiments as well as analysis of triggering mechanisms of unstable slopes in the field.
Dublin Bay Water Quality Modelling from Catchment to Coast
Authors: Corkery Aisling , Gao Guanghai , O'Sullivan John , Reynolds Liam , Sala-Comorera Laura , Martin Niamh , Stephens Jayne , Nolan Tristan , Meijer Wim , Masterson Bartholemew , Muldoon Conor , O'Hare Gregory
Published: March 2020

This paper presents the development and preliminary results of a deterministic modelling system for bathing water quality assessment in Dublin Bay, Ireland.  The system integrates functional capacity for simulating the transport and fate of diffuse agricultural pollutants (utilising both the NAM rainfall-runoff model in conjunction with MIKE 11), discharges from the Dublin urban drainage network (through MIKE Urban and InfoWorks software), and the ultimate fate of pollutants in Dublin Bay (coastal domain modelling utilises the 3-dimensional MIKE 3 code).  The work presented forms part of the EU INTERREG funded Acclimatize project (www.acclimatize.eu) that is investigating the longer-term water quality pressures in Dublin Bay that may arise in the context of a changing climate (particularly that from predicted changes in precipitation totals and patterns).  Model calibration and validation has been underpinned by extensive data collection from within the catchments discharging to Dublin Bay and from the bay area itself.  Catchment data includes the observing of hydrometeorological variables for establishing relationships to measured flows and water quality at catchment and sub-catchment scales.  Coastal data relates to water quality, coastal hydrodynamics (current speed and direction collected from ADCP deployments at multiple monitoring points in the bay), temperature and salinity.  A nested modelling approach where the modelled domain is nested in a larger Irish Sea model has been adopted.  Tidal constituents along the seaward boundaries of this nested model have been calibrated to correlate well with tidal measurements from a set of established tide gauges within the modelled domain.  Bottom friction was calibrated to produce good correlations of measured and simulated current speed and direction.  Preliminary results indicate that the transport of faecal indicator bacteria within the study area is adequately represented for spring and neap tide conditions.
The ERATOSTHENES Remote Sensing Supersite: Understanding the atmospheric system in the EMMENA region
Authors: Nisantzi Argyro , Mamouri Rodanthi-Elisavet , Michaelides Silas , Ansmann Albert , Bühl Johannes , Seifert Patric , Engelman Ronny , Wandinger Ulla , G. Hadjimitsis Diofantos
Published: March 2020

The Mediterranean Basin is well recognized by IPCC as a hot spot for climate change. Severe consequences are expected for the future in the Eastern Mediterranean, the Middle East and North Africa (EMMENA) region.

The increased urbanization, high pollution, dust storms and decreasing precipitation in the region dramatically affect climate change. Current prediction models for weather, climate, and environment are based on sophisticated modeling in close connection with state-of-the-art observations.

A modern observational super-site in Cyprus is of fundamental importance to understanding the atmospheric system in the EMMENA region. The presence of such a super site will be able to effectively monitor atmospheric conditions and provide relevant data for atmospheric prediction modeling.

This contribution reports on the recent progress regarding the buildup of a permanent, state-of-the-art atmospheric remote sensing station in Limassol, Cyprus. Through the EU H2020 Teaming project EXCELSIOR, the ERATOSTHENES Centre of Excellence (ECoE) will be established as a Centre of Excellence for Earth Surveillance and Space-Based Monitoring of the Environment.

The ECoE modern in-situ observational super site will be established in Cyprus for long-term profiling of the atmosphere, including wind, humidity, aerosol and cloud properties and precipitation fields. The ECoE will be fully in line with ESFRI networks, such as ACTRIS, as it will utilize state-of-the-art infrastructure and techniques to provide cutting-edge data regarding atmospheric processes.

As a demonstration initiative, an 18-month field campaign (Cy-CARE (Cyprus Cloud Aerosol and pRecipitation Experiment)) has been designed by the Leibniz Institute for Tropospheric Research (TROPOS) and was implemented by the ERATOSTHENES group at Cyprus University of Technology (CUT) between October 2016 and March 2018, with the main focus on lidar/radar-based studies of aerosol-cloud-precipitation relationships. Case studies of the Cy-CARE campaign will be presented to demonstrate the importance of the ground based atmospheric remote sensing observations in the region.

Acknowledgements

The authors acknowledge the EXCELSIOR project that received funding from the European Union [H2020-WIDESPREAD-04-2017:Teaming Phase2] project under grant agreement no. 857510, and from the Republic of Cyprus. CUT team acknowledge ACTRIS-2 project (H2020-INFRAIA-2014-2015, GA no. 654109) and the Research and Innovation Foundation of Cyprus for the financial support through the SIROCCO (EXCELLENCE/1216/0217) and AQ-SERVE (INTERGRATED/0916/0016) projects.
Unravelling magma emplacement through palaeomagnetic backstripping of an intrusion-induced forced fold: A case study from the Sandfell Laccolith, SE Iceland
Authors: McCarthy William , Twomey Vincent , Magee Craig , Petronis Mike
Published: March 2020

Volcano eruption forecasting typically links ground deformation patterns to sub-surface magma movement. Injection and inflation of magmatic intrusions in the shallow crust is commonly accommodated by roof uplift, producing intrusion-induced forced folds that mimic the geometry of underlying igneous bodies. Whilst such forced folds have previously been described from field exposures, seismic reflection images, and modelled in scaled laboratory experiments, the dynamic interaction between progressive emplacement of hot magma, roof uplift, and any associated fracture/fault development remains poorly understood. For instance, analysis of ancient examples where magmatism has long-since ceased only provides information on final geometrical relationships, while, studies of active intrusions and forced folding only capture brief phases of the dynamic evolution of these structures. If we could unravel the spatial and temporal evolution of ancient forced folds, we could therefore acquire critical insights into magma emplacement processes and interpretation of ground deformation data at active volcanoes.

 

We put forth and aim to test a new hypothesis suggesting that thermoremanent magnetization (TRM) records progressive deflection of the host rock during incremental laccolith construction and that these measurements can be used to measure the rate of laccolith construction. Here, we integrate palaeomagnetic techniques with semi-automated, UAV-based photogrammetric structural mapping to test: (1) whether we can identify variations in Natural Remanent Magnetisation (NRM), TRM, and magnetic mineralogy across an intrusions structural aureole; and (2) whether measured magnetic variations can be related to deflection caused by incremental sheet emplacement. Our test site is located within the basaltic lava pile of the ~800 m wide structural aureole of the rhyolitic Sandfell Laccolith in SE Iceland, which intruded <1 Km below the palaeosurface at ~11.7 Ma. We discuss whether palaeomagnetic backstripping can be an effective resource to constrain the rate and magnitude of intrusion-induced forced fold evolution, and thus an effective tool in volcanic hazard assessment.