bluuebunny/crossref_metadata_2025 huggingface dataset:
Oligocene-Miocene tectonics of the SW Alps and western Apennines coupled orogenic belts, as recorded by their internal and external syn-orogenic basins
Authors: Barale Luca , Fabrizio Piana , Carlo Bertok , Anna d'Atri , Andrea Irace , Luca Martire
Published: March 2020

The Oligocene-Miocene evolution of the westernmost part of the Northern Apennines was constrained firstly by Oligocene E-W regional sinistral shearing and then by Early Miocene shortening and Middle to Late Miocene NW-SE dextral transpression affecting the southern termination of the Western Alps arc (Maritime and Ligurian Alps) and the substrate of the Tertiary Piemonte Basin (TPB), which started to be incorporated, in the same time span, in the Northern Apennines belt

In other words, the dynamics accommodating the different motion of the WNW-directed Adria and SW Alps with respect to the ENE-directed Ligurian-Corso-Sardinian block also controlled the evolution of TPB and its Ligurian substrate since at least the Aquitanian, when a regional conterclockwise rotation began and a deep reshaping of the basin occurred, due to predominant NE-SW shortening concomitant with the Northern Apennines thrust fronts propagation (Burdigalian). On the other side, the infilling of the SW Alps foreland basin was partially controlled also by the resedimentation of non-metamorphic Cretaceous-Paleocene Ligurian units previously deposited along the Briançonnais-Dauphinois continental margin. The subsequent Late Burdigalian to Serravallian extension in the internal side of the SW Alps allowed the creation of accomodation space and the deposition of relevant thickness of sediments in the TPB, during the coeval progressive uplifting of Alpine crystalline and metamorphic units (e.g. the Argentera Massif and Dora-Maira Unit). This Alpine process constrained the shape and evolution of the TPB syn-orogenic sub-basins and their subsequent tectonic paths within the NW Apennines belt, while it was being built. The steps of this Alps-Apennines evolution have been clearly recorded by a set of regional scale, Oligocene to Pleistocene unconformities that can be continuously traced at surface in the southern part of the Piemonte region and in the subsurface of the western Po plain.

We thus remark that the evolution of the westernmost part of the Apennines can be studied largely referring to the Alpine geodynamics, since, although the Alps and the Apennines are two distinct geomorphologic and geophysical entities at the scale of the Western Mediterranean area, they share common synorogenic basins and consistent kinematic evolution in their junction zone of NW Italy.
Palaeo cell size: A Novel Technique to Investigate the Coccosphere Fossil Record using Imaging Flow Cytometry
Authors: Langley Beth , Halloran Paul , Power Ann , Rickaby Rosalind , Love John
Published: March 2020

Fossil coccospheres provide a wealth of information on cellular traits that can be compared directly to the living coccosphere such as cell size. Cell size is critical to ecosystem dynamics and particle sinking which has implications on the carbon cycle. However, cell size reconstruction is hindered by the poor preservation of coccospheres as coccospheres often disintegrate into individual coccoliths. Although palaeoecological information can be attained from individual coccoliths, assumptions must be made when correlating cell size to coccolith size. We demonstrate a novel technique using imaging flow cytometry to rapidly and reliably sort coccospheres from marine sediment by exploiting their unique optical and morphological properties. Imaging flow cytometry combines the functional insight of morphological information provided by microscopy with high sample numbers that are associated with flow cytometry. High throughput imaging overcomes the constraints of laborious manual microscopy enabling the analysis of sediments containing low concentrations of coccospheres that would simply not be feasible to manually hunt for coccospheres. By applying this technique to the fine fraction of sediments, hundreds of coccospheres can be isolated without the need for additional sample processing. Morphological information of individual coccospheres is obtained and graphical and statistical information can be extracted. This approach lends itself perfectly to rapid processing of down-core sediment samples or high spatial coverage from core-top samples and may prove valuable in investigating the interplay between a changing climate and coccolithophore response.

 
Monitoring groundwater depletion in Iran from space: results from gravity and InSAR observations
Authors: Haghshenas Haghighi Mahmud , Motagh Mahdi
Published: March 2020

Iran is located in a semi-arid to arid environment and is highly dependent on its groundwater resources for development in its agricultural and industrial sectors. In many aquifers across the country, unsustainable groundwater extraction in the past few decades caused severe groundwater level decline, at locations exceeding 20 m. The country is divided into six major basins. However, neither the water consumption nor renewable water resources are distributed evenly. Quantitative assessment of the groundwater situation in different basins is a piece of crucial information for improving management practices. In this study, we use satellite observations to assess the groundwater situation across Iran.

We observe the terrestrial water storage (TWS) from Satellite gravimetry measurements of Gravity Recovery And Climate Experiment (GRACE). These observations provide a country-scale picture of groundwater variations at a coarse spatial resolution of 500 km. In all six basins, TWS declines during the 15 year lifetime of GRACE from 2002 until 2017. In total, the Equivalent Water Height (EWH) declines as much as approximately 10 cm during this period. Although part of this decline is caused by other components such as surface water or soil moisture, groundwater decline is responsible for the major part.

The compaction of aquifers resulted from the over-extraction of groundwater can be observed as land subsidence on the surface. We analyze ground subsidence for the whole Iran using Interferometric Synthetic Aperture Radar (InSAR) observations of the Copernicus Sentinel-1 satellite and present the first detailed map of compacting aquifers across the country at a high spatial resolution of 100 m. The average rate of displacement, exceeding 30 cm/yr in some areas, reveals hundreds of aquifers across the country are suffering unsustainable groundwater consumption. The distribution of subsidence basins is significantly correlated with the distribution of agricultural regions.

To obtain information on the sustainability of groundwater consumption, we separate the time series of land subsidence into two parts: the short term part as elastic/recoverable component and the long-term part as inelastic/irrecoverable. The ratio between elastic and inelastic elements provides quantitative measurements of aquifer health. Combining the Sentinel-1 subsidence measurements with GRACE observations of groundwater variations gives us new details on how the groundwater is consumed across different basins in the country. The results can have essential implications on the more sustainable management of groundwater resources.
The effect of horizontal diffusion parameterization in convection-permitting REMO-NH simulations over Germany
Authors: Frisius Thomas , Jacob Daniela , Reca Remedio Armelle , Sieck Kevin , Teichmann Claas
Published: March 2020

Moving towards convection permitting simulations up to few kilometers scale are emerging solutions to the challenge and complexities in simulating different convective phenomena especially over mountainous regions. In this study we execute sensitivity experiments with the non-hydrostatic regional climate model REMO-NH at convection permitting resolution (~3km). We use this model in three setups where different parameterization schemes for horizontal diffusion are tested. In the first setup “DIFF2” we utilize the standard 2nd order diffusion while the second setup “DIFF4” applies 4th order diffusion. The higher order has a smaller impact on larger scales so that the atmospheric fields exhibit more details, especially in regions with high convective activity. In the third setup “TURB3D”, REMO-NH runs with a new 3D Smagorinsky-type turbulence scheme instead of the artificial diffusion schemes. Though turbulent horizontal diffusion is of second order in this setup, it incorporates a spatially and temporally varying exchange coefficient so that flows with little deformation remain unaffected. The domain of the simulations driven with EURO-CORDEX boundary data covers Germany and the time integration spans the year 2006.

Selected cases reveal a better representation of convective elements in DIFF4 and TURB3D when compared with DIFF2. We cannot compare these individual cases directly to observations since REMO-NH is not a reanalysis but a climate model. However, the spatial precipitation fields deduced from DWD radar data have characteristics which are more similar to DIFF4 and TURB3D than to DIFF2. More details are resolved in DIFF4 and TURB3D since the diffusion mainly act at the smallest spatial scales resolved by the model. DIFF2 smoothes convective activity drastically so that it appears in the form of unrealistically wide convective cells. On the other hand, the statistics of precipitation (seasonal average, standard deviation and 95th percentile) show a better agreement with observations in the simulation DIFF2 and TURB3D. TURB3D appears to be the best compromise regarding the simulation of precipitations fields. However, TURB3D exhibits a warm bias in the 2m temperature field in autumn and winter. Further model development may help to overcome this issue.
The sensitivity of atmospheric blocking to changes in upstream latent heating
Authors: Pfahl Stephan , Steinfeld Daniel , Boettcher Maxi , Forbes Richard
Published: March 2020

Recent climatological studies based on trajectory calculations have pointed to an important role of latent heating during cloud formation for the dynamics of blocking anti-cyclones. However, the causal relationship between latent heating and blocking formation has not yet been fully elucidated. To explicitly study this causal relationship, we perform sensitivity simulations of selected blocking events with a global weather prediction model in which we artificially eliminate latent heating in clouds upstream of the blocking anti-cyclones. This elimination has substantial effects on the upper-tropospheric circulation in all case studies, but there is also significant case-to-case variability: some blocking systems do not develop at all without upstream latent heating, while for others the amplitude of the blocking anticyclones is merely reduced. This strong influence of latent heating on the upper-level circulation is due to a combination of two effects: the direct injection of air masses with low potential vorticity (PV) into the upper troposphere in strongly ascending “warm conveyor belt” airstreams, and the indirect effect owing to the interaction of the associated divergent outflow with the upper-level PV structure. The important influence of diabatic heating demonstrated with these experiments suggests that an accurate parameterization of microphysical processes in weather prediction and climate models is crucial for adequately representing blocking dynamics.
Transferring geo-/mineralogical information to THM simulations of HLW storage in claystone formations (BASTION II)
Authors: Kumar Vinay , Kneuker Tilo , Maßmann Jobst
Published: March 2020

The multi-barrier concept of HLW storage in geological formations relies on the thermo-, hydro-, mechanical (THM) and chemical properties of the potential host rock. In claystone, these properties are strongly influenced by its mineralogical composition and their spatial distribution.

As part of the first phase of the BASTION project, BGR carried out investigations in two areas. The geological part focused on the structural-lithological composition of various claystone formations. The numerical part investigated methods to integrate the drillcore-scale properties into formation-scale numerical THM models with the aim of being able to perform generic model studies at this scale. A major challenge in the first phase of the project was the conversion and transfer of data collected from structural and mineralogical studies to the input parameters required in the THM models for the simulation of generic site studies and future assessment cases.

In the current contribution, a further step is taken towards this purpose while retaining the focus on the determination of thermal parameters of claystone. The classification of the geological sub-units as facies types in claystone has been extended with the introduction of the sub-facies concept, thus allowing a finer resolution in the classification within each facies type. The introduction and standardization of this concept for claystone are foreseen to allow a more precise choice of samples for the experimental determination of (thermal) parameters. This workflow is presented as a proof-of-concept and is utilized in a simplified simulation to evaluate its benefits. Extension of the concept to other input parameters of numerical THM models will be touched upon. The presented concept contributes towards the continuing effort to integrate data from drillcore-scale measurements in formation-scale simulations.
Crustal viscosity and its control on volcanic ground deformation patterns
Authors: Head Matthew , Hickey James , Gottsmann Jo , Fournier Nico
Published: March 2020

Episodes of ground deformation, relating to the unrest of a volcanic system, are often readily identifiable within geodetic timeseries (e.g. GPS, InSAR). However, the underlying processes facilitating this deformation are more enigmatic. By modelling the observed deformation signals, the ultimate aim is to infer characteristics of the deforming reservoir; namely the size and time-dependent evolution of the system and, potentially, the fluxes of magma involved. These parameters can be estimated using simple elastic models, but the presence of shallow or long-lived magmatic systems can significantly perturb the local geothermal gradient and invalidate the elastic approximation. Inelastic rheological effects are increasingly utilised to account for these elevated thermal regimes, where a component of viscous (time-dependent) behaviour is expected to characterise the observed deformation field.

Here, our investigations are concentrated on Taupō volcano, New Zealand, the site of several catastrophic caldera-forming eruptions. We use 3D thermomechanical models of the Lake Taupō region, featuring thermal constraints and heterogeneous crustal properties, to compare the commonly-used Maxwell and Standard Linear Solid (SLS) viscoelastic configurations under contrasting deformation mechanisms; a pressure condition (stress-based) and a volume-change (strain-based). By referring to models allocated a single viscosity value, we investigate the influence of a temperature-dependent viscosity distribution on the predicted spatiotemporal deformation patterns. Comparisons of the overpressure models highlights the influence of the crustal viscosity structure on deformation timescales, by enabling the SLS rheology to account for both abrupt and long-term deformation signals. For the Maxwell rheology, we show that the viscosity distribution results in unexpected deformation patterns, both spatially and temporally, and so query the suitability of this rheology in other model setups. Further to this, the deformation patterns in volume-change models are governed by the resulting stress response, and the effect of the viscosity structure on its propagation. Ultimately, we demonstrate that variations in crustal viscosity greatly influence spatiotemporal deformation patterns, more so than heterogeneous mechanical parameters alone, and consequently have a large impact on the inferences of the underlying processes and their time-dependent evolution. The inclusion of a crustal viscosity structure is therefore an important consideration when modelling volcanic deformation signals.
Insect Damaged Tree Detection with Drone Data and Deep Learning Technique, Case Study: Abies Mariesii Forest, Zao Mountain, Japan
Authors: Ha Trang Nguyen , Diez Yago , Lopez Larry
Published: March 2020

The outbreak of fir bark beetles (Polygraphus proximus Blandford) in natural Abies Mariesii forest on Zao Mountain were reported in 2016. With the recent development of deep learning and drones, it is possible to automatically detect trees in both man-made and natural forests including damaged tree detection. However there are still some challenges in using deep learning and drones for sick tree detection in mountainous area that we want to address: (i) mixed forest structure with overlapping canopies, (ii) heterogeneous distribution of species in different sites, (iii) high slope of mountainous area and (iv) variation of mountainous climate condition. The current work can be summarized into three stages: data collection, data preparation and data processing. All the data were collected by DJI Mavic 2 pro at 60-70m flying height from the take off point with ground sampling distance (GSD) are ranging from1.23 cm to 2.54 cm depending on the slope of the sites. To prepare the data to be processed using a Convolutional Neural Network (CNN), all images were stitched together using Agisoft’s metashape software to create five orthomosaics of five study sites. Every site has different percentage of fir according to the change of elevation. We then manually annotated all the mosaics with GIMP to categorize all the forest cover into 6 classes: dead fir, sick fir, healthy fir, deciduous trees, grass and uncovered (pathway, building and soil). The mosaics are automatically divided into small patches with the assigned categories by our algorithm with first trial window size of 200 pixel x 200 pixel, which we temporally see can cover the medium fir trees. We will also try different window sizes and evaluate how this parameter affects results. The resulting patches were finally used as the input for CNN architecture to detect the damaged trees. The work is still on going and we expect to achieve the results with high classification accuracy in terms of deep learning algorithm allowing us to build maps regarding health status of all fir trees.

 

Keywords: Deep learning, CNN, drones, UAVs, tree detection, sick trees, insect damaged trees, forest

 
Characterizing sediment dewatering and constraining spatially limited fluid flux in accretionary systems. A rock magnetic approach.
Authors: Greve Annika , Kars Myriam , Stipp Michael , Dekkers Mark
Published: March 2020

The dewatering and subsequent drainage of fluids from porous sediments in forearc regions controls heat flux and the frictional behavior of the plate boundary decollement and all other forearc faults. Here we present new rock magnetic datasets that help to depict the strain history and locus of fluid and gas migration across a shallow subduction thrust near the deformation front of the Hikurangi subduction margin (New Zealand). Site U1518 of International Ocean Discovery Program (IODP) Expedition 375 penetrated hanging-wall, the roughly 60 m thick fault-zone, and footwall sequences of the Pāpaku fault up to a maximum depth of 504 mbsf.

Rock magnetic investigations include the measurement of Anisotropy of Magnetic Susceptibility (AMS), static three-axis alternating field demagnetization (AFD), magnetic hysteresis, anhysteretic remanence acquisition (ARM) and S-ratio measurement. The datasets are presented for an interval between 275 and 375 mbsf, and encompass both fault-zone and directly adjacent sequences.

Throughout most of the sedimentary sequence, samples yield intensities of the natural remanent magnetization (NRM) between 10-5 and 10-6 Am2/kg. Magnetic coercivities range from 40 to 60 mT. During static AFD samples acquired a gyroremanent magnetization. These observations indicate the presence of authigenic greigite (Fe3S4). In two intervals, between 304 and 312, and 334 - 351 mbsf, samples yield distinctively lower remanence intensities (~ 10-7 Am2/kg) and lower coercivities around 20 mT. The upper interval coincides with the onset of brittle deformation at the top of the fault-zone. In the same interval AMS results change abruptly. We propose that the rock magnetic signature is due to the reduction of ferrimagnetic greigite to paramagnetic pyrite (FeS2). This is most likely caused by the drainage of methane-, and sulfide rich fluids/gas along the upper fault-zone and supports interpretations that the fault zone acts as effective conduit. A continued transport of fluids/gases could have promoted a self-sustaining weakening and strain decoupling with episodic high pore-fluid pressure within localized parts of the fault-zone.
From InSAR derived relative tropospheric Slant Total Delay maps to absolute Zenith Total Delay maps: comparisons between tropospheric delay products to define a strategy for meteorological applications.
Authors: Barindelli Stefano , Gatti Andrea , Lagasio Martina , Manzoni Marco , Mascitelli Alessandra , Monti Guarnieri Andrea , Montrasio Marco , Realini Eugenio , Tagliaferro Giulio , Venuti Giovanna
Published: March 2020

InSAR derived Atmospheric Phase Screens (APSs) contain the difference between the atmospheric delay along the SAR sensor line-of-sight of two acquisition epochs: the slave and the master epochs. Using estimates of the atmospheric state at the master epoch, coming from independent sources, the APSs can be transformed into maps of tropospheric Zenith Total Delay (ZTD), that is related to the columnar atmospheric water vapor content. Assimilation experiments of such products into numerical weather prediction (NWP) models have shown a positive impact in the prediction of convective storms.

In this work, a systematical comparison between various APS and ZTD products aims at determining the optimal procedure to go from APSs to InSAR-derived absolute ZTD maps, i.e. to estimate the master delay map. Two different approaches are compared.

The first is based on a stack of ZTD maps produced with the assimilation of GNSS ZTD observations into an NWP model. This acts as a physically based interpolator of the GNSS values, which have a spatial resolution much coarser than the InSAR APS one.

The second is based on a stack of ZTD maps derived by an Iterative Tropospheric Decomposition (ITD) model, as implemented in the GACOS service. In this case, the high-resolution ZTD maps are obtained by an iterative interpolation of a global atmospheric circulation model values and GNSS values where available.

The results of the comparisons and sensitivity tests on the number of ZTD maps needed to derive the unknown master delay map are shown.

 

 

 

 

 
Utilization of fire brigade data in the impact analysis of extreme precipitation events over Berlin
Authors: Pasternack Alexander , Langer Ines , Rust Henning , Ulbrich Uwe
Published: March 2020

Large cities and urban regions are highly sensitive to impacts caused by extreme events, e.g. heavy rainfall, since they cause fatalities and economic damages. Moreover, due to regional consequences of global climate change, problems caused by hazardous atmospheric events are expected to intensify in future. Thus adequate adaptation planning of urban infrastructure not only requires further research on potential impacts under changing precipitation patterns, but also practical feasibility for end users like insurances or fire brigades.

According to this we relate heavy precipitation events over Berlin to the available data on time and location of the respective fire brigade operations, within the research program “Urban Climate Under Change” ([UC]2) funded by the BMBF. For this purpose multiple data sets like station, radar and model  based data with a high temporal resolution will be used.  Thus an improved assessment of the spatial and temporal evolution of severe precipitation events can be made,  which is consequently also of aid in the investigation of a connection to related impacts in the urban area.
Effects of Interactions Between Society and Environment on Policy in Water Resources Management: Exploring Scenarios of Natural and Human-Induced Shocks
Authors: Borzì Iolanda , Sivapalan Murugesu , Bonaccorso Brunella , Viglione Alberto
Published: March 2020

In many regions of the world, water supply is threatened by natural hazards such as floods and droughts, as well as by shocks induced by anthropogenic changes to water use. Lack of anticipation and/or preparation for these events can lead to delayed or insufficient responses to sudden or developing water crises, that sometimes can produce irrecoverable damage to the environment. In this work, a socio-hydrological approach to sustainable water resources management of the Alcantara River Basin in Sicily (Italy) is adopted that explicitly takes into account feedbacks between the natural and the human components that might arise from shocks to the water management system, including possible evolution of policy responses. The Alcantara River Basin is a groundwater-fed catchment which supplies many villages on the Ionian coast up to Messina city, mainly through the Alcantara aqueduct, but also agricultural areas and industries, including hydropower plants. It also hosts the Alcantara Fluvial Park, an important natural reserve. The Alcantara aqueduct also supplied the city of Messina during a temporary failure of its main aqueduct caused by a landslide in October 2015. The main purpose of the work is to use the socio-hydrological model as a “screening tool” to frame water resource management issues in a broad way and provide guidance to the community to identify aspects of societal behavior that need to evolve towards sustainable water resource management in order to withstand future shocks. This has been done by scenario simulations in conditions of a natural shock affecting the system (i.e. drought) and of a human-induced one (i.e. increase in groundwater extraction). Sensitivity analysis of the model social parameters revealed how the value attributed by the society to the environment and water resources use, its capacity to remember previous water crises and, in particular, its previous responses to shocks, can affect the system in a way that can produce paradoxical effects. Results show how a rapid decision-making strategy that may work in the short term, can be counter-productive when viewed over the long term and how a do-nothing decision during a water crisis could be highly damaging to the environment. For the above-mentioned reasons, this socio-hydrological approach can be considered as a useful tool to understand human-water dynamics and to support decision-makers in water resource management policies with a broad and long-term perspective.
Rapid growth of NOx emissions in India observed from Space
Authors: Ding Jieying , van der A Ronald , Mijling Bas
Published: March 2020

Since the last decade, India has encountered severe problems in air quality and became the most air polluted country in the world.  With satellite observations, we can monitor the changes of NO2 column concentrations in India. However, the information on emissions is very limited. In this study, we use the KNMI DECSO (Daily emission Estimates constrained by Satellite Observation) algorithm to estimate NOx emissions from OMI observations from 2007 to 2018. The results show that NOx emissions have increased by about 40% in the last 12 years. We compare NOx emissions from DECSO and the HTAP bottom-up NOx emissions with the location and capacity of power plants in India. The comparison between DECSO and HTAP shows that the emissions estimated from satellite are more accurate on spatial and temporal scale. We also run the CHIMERE v2013 model with emissions from DECSO and HTAP respectively and compare the model simulations with NO2 in-situ measurements of the Indian national network. The comparison shows that model simulation with DECSO has lower bias and better correlation with in-situ observations than that with HTAP.  
ChessWatch: Observations on a Citizen Science approach to catchment management.
Authors: Heppell Catherine , Bartlett Angela , Beechey Allen , Jennings Paul , Souteriou Helena
Published: March 2020

River Chess is a chalk stream in South East England (UK), under unprecedented pressure from over-abstraction, urbanisation and climate change, which currently fails to meet good ecological status. Citizen Scientists have been active in the catchment for 9 years carrying out riverfly monitoring due chiefly to concerns about water quality and poor fish populations. The River Chess is also a pilot river for a new catchment-based ‘Smarter Water Catchments’ programme run by the region’s wastewater treatment company (Thames Water) which aims to work with local communities and regulators to deliver improvements to the river by tackling multiple challenges together. The community-led ChessWatch project is a part of this initiative, and is designed to raise public awareness of threats to the River Chess and involve the public in river management activities using a sensor network as a platform. In 2018 four water quality sensors were installed in the river to provide stakeholders with real-time water quality data (15-minute intervals) to support catchment management activities. The dataset from the project is intended to support future decision-making in the catchment as part of the five-year ‘Smarter Water Catchments’ approach.

Our presentation will review the successes and drawbacks of the ChessWatch project to date and examine the challenges of linking the data collected by the project to policy and practice in a catchment with multiple stakeholder groups. We present the results of a participatory mapping exercise held at local community events to capture the public use of, and concerns for, the river revealing concerns for low flows and water quality issues linked to abstraction and runoff. We show how dissolved oxygen, temperature, turbidity, chlorophyll-a and tryptophan measurements made by the sensors are enabling local stakeholders to better understand the threats to the river arising from urban runoff and changing rainfall patterns, and we examine the challenges of data presentation, sharing and usage in an urbanised catchment with high water demand and multiple conflicting interests.
Induced polarization for the spatial characterization of biogeochemical hot spots
Authors: Katona Timea , Gallistl Jakob , Nordsiek Sven , Bücker Matthias , Frei Sven , Durejka Stefan , Gilfedder Benjamin , Flores-Orozco Adrian
Published: March 2020

Biogeochemical hot spots are spatially confined areas where biogeochemical processes take place with anomalously high reaction rates. On the landscape scale, biogeochemical hot spots are of major interest due to the possible emission of greenhouse gases (carbon dioxide) and high nutrient turnover. Such hot spots are sensitive environments and given their environmental impact, there is a growing demand for noninvasive methods to investigate such hot spots without disturbing the biogeochemical settings. Classical geochemical sampling methods (e.g., piezometers or suction cups) often disturb the redox-sensitive settings by bringing oxygen into anoxic areas. Induced polarization (IP) is a noninvasive geophysical method that was initially developed to explore metal-ore deposits but more recently developed into a versatile tool for environmental studies.  Here, we present imaging results from a geophysical survey using the IP method to characterize hot spots in a wetland located in the Lehstenbach catchment in Southeastern Germany. We collected IP imaging data sets along 64 profiles using 64 electrodes deployed with a spacing of 20 cm. Our highly resolved measurements aimed at delineating hot spots within a thin layer (approximately 20 cm) heterogeneous peat material on top of the local granite bedrock. To validate the field-scale IP signatures, geochemical analyses (e.g., dissolved and solid iron concentration) were performed on freeze-core samples obtained in areas characterized by anomalous high and low IP responses. Furthermore, the thickness of the peat was measured with a dipstick along every fifth profile to evaluate the IP imaging results. Our imaging results reveal an increase in the IP response within the upper 20 cm of the subsurface, which correlates with the variations in the iron concentrations and variations in the geochemical composition of groundwater accompanying microbial activity within the biogeochemical hot spots observed in the soil samples. The IP response decreases in the deeper regions, which can be associated with the granite bedrock.
BepiColombo and Solar Orbiter coordinated observations: scientific cases and measurements opportunities
Authors: Hadid Lina , Dosa Melinda , Akos Madar , Alberti Tommaso , Benkhoff Johannes , Bebesi Zsofia , Griton Lea , C. Ho George , Iwai Kazumasa , Janvier Miho , Milillo Anna , Miyoshi Yoshizumi , Mueller Daniel , Murukami Go , M. Raines Jim , Shiota Daikou , Walsh Andrew , Zender Joe , Zouganelis Yannis
Published: March 2020

BepiColombo and Solar Orbiter are two spacecraft that will be both travelling in the inner heliosphere for 5 years, between the launch of Solar Orbiter (planned in February 2020) and the end of the cruise phase of BepiColombo (2018 - 2025). Both BepiColombo (ESA/JAXA) and Solar Orbiter (ESA/NASA) are carrying exceptional and complementary plasma instrumental payloads and magnetometers. Besides, the remote-sensing instruments on board of Solar Orbiter will provide invaluable information on the state of the Sun, and therefore some contextual information for BepiColombo observations. During the five years to come, BepiColombo will evolve between the Earth and the orbit of Mercury, while Solar Orbiter’s highly elliptical orbit will cover distances from 1.02 AU to 0.28 AU.  We present here the scientific cases, modelling tools, measurement opportunities and related instruments operations that have been identified in the frame of potential coordinated observations campaign between the spacecraft.
Participatory water resources monitoring as a science-policy tool: a decade of experience from the Andes
Authors: Ochoa-Tocachi Boris , Buytaert Wouter , De Bièvre Bert
Published: March 2020

Evidence-based decision making is seen as the key to sustainable water resource and catchment management. However, a major obstacle for evidence generation is the limited amount of data available from in-situ hydrometeorological monitoring. Monitoring is in decline globally, and this problem is particularly acute in high-elevation environments and in the tropics. Nevertheless, this situation also puts these environments in a promising position to study the potential of multi-source, polycentric generated information to tackle data scarcity.

Established in 2009, a bottom-up partnership of academic and non-governmental institutions pioneered participatory hydrological monitoring in the tropical Andes. Participatory approaches to environmental monitoring are becoming increasingly popular and are being promoted as a potential pathway to address long-standing data gaps. The partnership, known as the Regional Initiative for Hydrological Monitoring of Andean Ecosystems (iMHEA from its Spanish abbreviation) has instrumented a network of more than 30 headwater research catchments (< 20 km2) covering four major biomes (páramo, jalca, puna, and forest) in nine locations of the tropical Andes. Precipitation and streamflow are monitored at high frequency with the involvement of local communities, governments, and research institutions. The network is designed to characterize the impacts of changes in land use and watershed interventions on catchment hydrological response and has started delivering fundamental information to guide processes of decision making more effectively and influencing policy-making on water resources at local and national scales.

Participatory water resources monitoring can be seen a science-policy tool. Here we present the drivers and context of the process that led to the creation of iMHEA, currently one of the largest initiatives of grassroots and participatory environmental monitoring in the world, and the main challenges that lie ahead. Observational data from experimental catchments have an essential value for hydrology and water resources management that increases with time. The long-term sustainability in the monitoring will allow a deeper understanding of current uncertainties, including seasonality, natural variability, environmental changes, and extreme events such as drought and flooding.
The distribution and saturation of water vapor as inferred from ACS during the first Martian year of TGO Science observations
Authors: Fedorova Anna , Montmessin Franck , Korablev Oleg , Luginin Mikhail , Trokhimovskiy Alexander , Belyaev Denis , Alday Juan , Ignatiev Nikolay , Lefevre Franck , Olsen Kevin , Millour Ehouarn , Bertaux Jean-Loup , Shakun Alexey , Grigoriev Alexey , Patrakeev Andrey , Korsa Svyatoslav , Wilson Colin , Forget Francois , Maattanen Anna
Published: March 2020

The water vapour vertical distribution is an eloquent gauge of the relative roles of the various sources, sinks and processes that control the Martian water cycle. However, its behaviour is still poorly studied while it is instrument for our understanding of the loss of water from Mars to space, which results from the transport of water to the upper atmosphere where it is disassociated to hydrogen atoms that later escape. We use the Atmospheric Chemistry Suite on the ExoMars Trace Gas Orbiter to characterize the water distribution with altitude. Here we present results of the Atmospheric Chemistry Suite (ACS) instrument NIR channel for the first year of TGO observations covering the almost full year from Ls 160° of the Martian year 34 (April 2018) to Ls 130° of the Martian year 35 (January 2020). Simultaneous measurements of the water vapour mixing ratio, temperature and dust vertical distribution and formation of water ice clouds allow us to constrain the complex water behaviour and estimate the saturation state of H2O. Water profiles during the 2018-2019 southern spring and summer stormy seasons show that high altitude water is preferentially supplied close to perihelion and that large supersaturation occurs even when clouds are present. Here we attempt to complete the story by studying water vapor during the northern spring and summer to explore whether saturation impacts water transport between hemispheres in this season. The data analysis of MY35 was supported by RSF (project No. 20-42-09035).
Outreach and disseminations activities in North Slope of Alaska: how to build trust between local communities and arctic researchers
Authors: Erickson Kaare Sikuaq , Zona Donatella , Montemayor Marco , Oechel Walter , Zenone Terenzio
Published: March 2020

The Alaskan Ukpeaġvik Iñupiat Corporation (UIC) is promoting and financilally supporting, with the contribution of the US National Science Foundation (NSF) and local organizations, outreach and dissemination events, in the form of science fair for the local communities in North Slope of Alaska. The science fair is part of a larger effort by UIC Science to bring coordination and collaboration to science outreach and engagement efforts across Arctic Alaska. The purpose is to provide a positive space for Arctic researchers and Arctic residents to meet, eat with each other, spend time, and to inspire the youth of the Arctic by providing fun and educational activities that are based in science and traditional knowledge. The Science Fair 2019 hosted by the Barrow Arctic Research Center (BARC) included three days of youth and family-friendly activities related to “Inupiat Knowledge about Plants” led by the College Inupiat Studies Department, “Eco-chains Activity” hosted by the North Slope Borough Office of Emergency Management, “Big Little World: Bugs Plants, and Microscopes” hosted by the National Ecological Observatory Network, “Microplastics in the Arctic” hosted by the North Slope Borough Department of Wildlife Management, “BARC Scavenger Hunt” hosted by UIC Science, “Our Role in the Carbon and Methane Cycle” hosted by the University of Texas El Paso (UTEP) and San Diego State University, and “How Permafrost Works” hosted by the University of Alaska, Fairbanks, Geophysical Institute. Each day hundreds of students, from both the local community and the science community came together to take part in mutually beneficial engagement: students from Utqiaġvik were excited about science and now know of the realistic and fulfilling careers in research that takes place in their backyard. The Utqiaġvik community members and elders now have a better idea of the breadth of research that takes place in and near their home. The locals, especially the elders, are very concerned about the drastic changes in our environment: scientists share these concerns, and the discussions during the fair was a chance to recognize this common ground. Breaking the ice between Arctic researchers and residents can lead to endless opportunities for collaboration, sharing ideas, and even lifelong friendships.

 

 
An object-based approach for flood mapping in vegetated areas based on Sentinel-1 and Sentinel-2 imagery
Authors: Landuyt Lisa , Verhoest Niko , Van Coillie Frieke
Published: March 2020

Flooding is one of the most severe natural hazards with respect to both economic and human losses. Therefore, it is of prime importance to provide timely and accurate information about these events, both for emergency management and flood risk assessment. Synthetic Aperture Radar (SAR) sensors are particularly suited to provide flood observations given their all weather, day/night sensing capability and the distinctive backscatter characteristics of smooth water surfaces. Over the past years, a considerable number of SAR-based flood mapping approaches has been developed. However, most of these focus on the retrieval of open water surfaces only. Flood mapping in vegetated and urban areas remains challenging due to the more complex backscatter mechanisms occurring in these areas. Yet, accurate delineation of floods in these areas is all the more important given their economical and societal relevance.

This study focuses on the retrieval of flood extent information in complex, vegetated landscapes by means of freely available data. The considered imagery includes a pair of Sentinel-1 images, one acquired before and one acquired during the flood, as well as a cloud free Sentinel-2 image or mosaic acquired under non-flooded but representative vegetative conditions. An object-based change detection approach is used. Grouping pixels into segments prior to further analysis allows the integration of contextual and morphological information as well as the combination of different information sources. Segmentation is achieved by means of the quickshift algorithm, considering both polarization bands of the SAR image pair. Next, object properties with respect to SAR backscatter, surface reflectance and elevation are calculated and objects are grouped using spectral clustering. By including optical imagery, vegetation cover is considered and the flooded vegetation class can be better discriminated. The resulting clusters are then assessed, analysed and classified. Post-processing is done by means of contextual and topographical information. The use of fuzzy logic allows to assign an uncertainty measure to the obtained classification. For full scene processing, a thresholding-based preliminary flood extent is first derived in order to speed up the classification process and correct for class imbalance. The approach is presented based on multiple study cases, amongst which the 2019 floods along the Sava River, Croatia.
Dynamic weakening mechanism in Earth’s mantle - A comparison between damage-dependent weakening and grain-size sensitive rheologies
Authors: Fuchs Lukas , Becker Thorsten W.
Published: March 2020

The creation and maintenance of narrow plate boundaries and their role in the thermo-chemical evolution of Earth remain one of the major problems in geodynamics. In particular, the cause and consequences of strain localization and weakening within the upper mantle remain debated, even though strain memory and tectonic inheritance, i.e. the ability to preserve and reactivate inherited weak zones over geological time, and strain localization appear to be critical features in plate tectonics.

Frictional-plastic faults in nature and brittle shear zones in the lithosphere may be weakened by high transient, or static, fluid pressures, or mechanically by gouge, or mineral transformations. Weakening in ductile shear zones in the viscous domain may be governed by a change from dislocation to diffusion creep caused by grain-size reduction. In mechanical models, strain weakening and localization in the shallow parts of the lithosphere has mainly been modeled by an approximation of brittle behavior using a pseudo visco plastic rheology. This has often been implemented by a linear decrease of the yield strength of the lithosphere with increasing deformation. Strain weakening in viscous shear zones, on the other hand, may be described by a linear dependence of the effective viscosity on the accumulated deformation.

Here, we analyze how a parameterized, apparent-strain, or “damage”, dependent weakening (SDW) rheology governs strain localization and weakening as well as healing in the lithosphere. The weakening and localization due to the SDW rheology has been related to a grain-size sensitive (GSS) composite rheology (diffusion and dislocation creep). While we focus on GSS rheology to constrain the parameters of SDW, the analysis is not limited to grain-size evolution as the only possible microphysical mechanism. We explore different types of strain weakening (plastic- (PSS) and viscous-strain (VSS) softening) and compare them to the predictions from different models of grain-size evolution for a range of temperatures and a step-like variation of total strain rate with time. PSS leads to a weakening and strengthening of the effective viscosity of about the same order of magnitude as due to a GSS rheology, while the rate depends on the strain-weakening parameter combination. In addition, the SDW weakening rheology allows for memory of deformation, which weakens the fault zone for a longer period. Once activated, the memory effect and weakening of the fault zone allows for a more frequent reactivation of the fault for smaller strain rates, depending on the strain-weakening parameter combination.
Equilibrium Climate Sensitivity in AWI-ESM: Mechanisms and Effects
Authors: Danek Christopher , Gierz Paul , Stepanek Christian , Lohmann Gerrit
Published: March 2020

The global-mean surface air temperature change due to a doubled carbon dioxide concentration in the atmosphere (equilibrium climate sensitivity, ECS) is an important measure to quantify the impact of predicted anthropogenic climate change. The latest climate modeling intercomparison project (CMIP6) exhibits a higher ECS compared to the previous climate model generation (1.8 to 5.6 K for CMIP6 versus 1.5 to 4.5 K for CMIP5). The increase in ECS is likely due to decreases in extratropical low cloud coverage and albedo, caused by improvements in the numerical aerosol schemes. Our state-of-the-art Earth system model AWI-ESM, developed at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, yields an ECS of 3.59-3.62 K, which is close to the CMIP5 mean. Using a set of varying model configurations, we identify dynamic vegetation and model resolution as the primary driving factors which influence the modeled global response to an increased greenhouse gas forcing.