bluuebunny/crossref_metadata_2025 huggingface dataset:
Seasonal variability of eddy kinetic energy in southeastern Arabian Sea
Authors: Mohan Pillai Ullas , Joseph Kochuparampil Ajith , Pappukutty Raj Roshin , Mathias Johannessen Ola
Published: March 2022

Eddy kinetic energy (EKE) is a measure of temporal and spatial variability of ocean mesoscale eddies . This study elucidates the key factors that determine the spatial distribution and seasonality of mesoscale eddies of the south-eastern Arabian sea (SEAS) using satellite observational data from Copernicus Marine service data centre, during the time period 1993-2016. In general eddy kinetic energy is found to higher during winter. The higher EKE throughout the winter were found to be due to the barotropic instability of the Winter Monsoon Current . This is owing to current’s barotropic instability due to wind stress curl, resulting in the conversion of mean kinetic energy to eddy kinetic energy. The ESA OC-CCI data were used to study the influence of EKE on the primary productivity using linear regression and correlation analysis. A significant positive correlation between EKE and chlorophyll-a concentration during winter monsoon indicates the impact of EKE on the distribution of surface chlorophyll-a concentration over the SEAS during winter monsoon.  
Analysing the influence of different temporal resolutions of water consumption data for leakage detection and localisation
Authors: Oberascher Martin , Halm Andreas , Ullrich Torsten , Sitzenfrei Robert
Published: March 2022

Digital water meters are increasingly installed in water distribution networks providing detailed information about the water consumption in households at a high temporal resolution (e.g., ranging from seconds to daily readings). While the benefit on household scale is well described in literature (e.g., scarcity billing, awareness raising, leakage detection in domestic installations), recent research is also investigating the potential of digital water meters for an accurate fault management on network scale. In this context, water losses represent a major challenges for the operation of water distribution networks (WDNs), and a timely detection and localisation of water leakages is of greatest interest to reduce these losses. Especially model-based techniques require accurate nodal demands for the numerical simulation of the hydraulic states, which can be obtained for example by using high resolution consumption data.

Therefore, the aim of this work is to first investigate the influence of different temporal resolution of household water consumption data and to define an optimal temporal resolution for the detection and localisation of water leakages. However, power supply (e.g., transmission interval), communication technology (e.g., packet losses), and urban population (e.g., consumer agreement to digital water meters) influence the temporal and spatial quality of data received in a real-word implementation and may differ from the optimal performance. Therefore, different methods are tested to overcome the data gaps caused by data transmission and availability uncertainties. As case study, a real WDN from a pilot project in the city of Klagenfurt is used which is extended by artificial water demand series (temporal resolution varies between 1 min and 24 h) and water leakages. Following, performance of leakage detection (data-based approach) and localisation (model-based approach) in combination with machine learning techniques is evaluated by using detection time and distance between leakage and identified location as selected indicators.

The first results showed that the temporal resolution of consumption data influences the applicable methods for an efficient leakage detection and localisation. For example, water consumption data with a temporal resolution of 15 min allow an accurate mapping of consumption fluctuations, therefore the difference between inflow and measured values is very well suited to identify leakages. In contrast, using the same technique for 24 h consumption data (e.g., difference from inflow and daily mean value), the morning and evening peak would also be indicated as a possible leakage and thus requiring different approaches.
Land use options for Viticulture in Portugal in light of bioclimatic shifts
Authors: Andrade Cristina , Fonseca André , A. Santos João
Published: March 2022

Climate and land are closely intertwined through multiple interface processes. On one hand, land endows means for agriculture practices and agroforestry systems thus contributing to the food and materials supply; on the other, climate change may lead to significant impacts in land use and efficient water availability and management. Therefore, the study of these interactions and the impact of the bioclimatic shifts, since land use, plays a relevant role in the climatic system is highly relevant.

Towards this aim, in this study, 1‒km observational gridded datasets are used to assess changes in the Köppen–Geiger and Worldwide Bioclimatic (WBCS) Classification Systems in mainland Portugal. As such, two past periods were analyzed: 1950–1979 and 1990–2019. A compound bioclimatic-shift exposure index (BSEI) is defined to identify the most exposed regions to recent climatic changes. The temporal evolution of land cover with vineyards between 1990 and 2018, as well as correlations with areas with bioclimatic shifts, are then analyzed.

Results show significant climatic changes between the two periods with an increase of 18.1% in the Warm Mediterranean with hot summer (CSa) climate in Portugal. This increase was followed by a 17.8% decrease in the Warm Mediterranean with warm summer (CSb) climate. Furthermore, the WBCS Temperate areas also reveal a decrease of 5.11%. Arid and semi-arid ombrotypes areas increased, whilst humid to sub-humid ombrotypes decreased. Thermotypic horizons depict a shift towards warmer classes. BSEI highlights the most significant shifts in northwestern Portugal.

Overall results show that vineyards have been displaced towards regions that are either the coolest/humid, in the northwest, or the warmest/driest, in the south. Since vineyards in southern Portugal are commonly irrigated, options for the intensification of these crops in this region may threaten the already scarce water resources and challenge the future sustainability of this sector. As similar problems can be found in other regions with Mediterranean-type climates, the main findings of this study can be easily extrapolated to other wine producer countries worldwide.

Acknowledgement: This work was supported by National Funds by FCT - Portuguese Foundation for Science and Technology, under the project UIDB/04033/2020.

Keywords: Köppen-Geiger Climate Classification, Worldwide Bioclimatic Classification System (WBCS), Vineyards, Portugal.
Temperature prediction with expert agregation
Authors: Pfitzner Léo , Mestre Olivier , Wintenberger Olivier , Adjakossa Eric
Published: March 2022

A lot of Numerical Weather Prediction (NWP) models and their associated Model Output Statistics (MOS) are available. Expert aggregation has a bunch of advantages to deal with all these models, like being online, adaptive to model changes and having theoretical guarantees. With a new expert aggregation algorithm - FSBOA - a combination of BOA (Wintenberger 2017) and FS (Herbster and Warmuth 1998), and the use of a sliding window, we improved the temperature prediction on average without loosing too much reactivity of the expert weights. We also tested several aggregation strategies in order to improve the prediction of  extrem temperature events like cold and heat waves. To do so, we added some biased experts of the Météo-France 35-member ensemble forecast (PEARP) to the set of models. We also tried out the SMH (Mourtada et al. 2017) algorithm which fits the sleeping experts framework.
The Global Mass and Average Rate of Rubisco
Authors: Bar-On Yinon , Milo Ron
Published: March 2022

Photosynthetic carbon assimilation enables energy storage in the living world and produces most of the biomass in the biosphere. Rubisco (D-ribulose 1,5-bisphosphate carboxylase/oxygenase), is responsible for the vast majority of global carbon fixation, and has been previously claimed to be the most abundant protein on Earth. Here, we provide an updated and rigorous estimate for the total mass of Rubisco on Earth, concluding it is ≈0.7 Gt, more than an order of magnitude higher than previously thought. We find that >90% of Rubisco enzymes are found in the ≈2x1014 m2 of leaves of terrestrial plants, and that Rubisco accounts for ≈3% of the total mass of leaves which we estimate at ≈30 Gt dry weight. We use our estimate for the total mass of Rubisco to derive the effective time-averaged catalytic rate of Rubisco and find that it is ≈0.03 s-1 on land and ≈0.6 s-1 in the ocean. In comparison to the maximal catalytic rate observed in vitro at 25℃, the effective rate in the wild is ≈100-fold slower on land and ≈7-fold slower in the ocean. The lower ambient temperature, and Rubisco not working at nighttime, are enough to explain most of the difference from lab conditions in the ocean, which implies that in the ocean Rubisco is working close to its maximal catalytic capacity. This is not the case for land Rubiscos, and therefore motivates future quantification of many more factors on a global scale.
Logging residues promote positive interactions between soil erosion, soil functioning and soil macrofauna diversity in young rubber plantations in Africa.
Authors: Mareschal Louis , Janeau Jean-Louis , Legrand Marianne , Gay Frédéric , Kouakou Aymard , Brauman Alain , Manizan Antoine , Laclau Jean-Paul , Perron Thibaut
Published: March 2022

Soil erosion causes major problems of land degradation in agricultural systems leading to losses of soil fertility. Rubber tree is one of the main tropical perennial crops with about 13 million hectares of plantations worldwide in 2018. In the early stage of a rubber plantation, soil is especially vulnerable to degradations given the low canopy cover and heavy soil surface disturbance related to clear-cutting of the previous plantation. This study aims at assessing runoff and soil losses as well as understanding the main soil factors influencing soil erosion in a young rubber plantation in Côte d’Ivoire. We intensively measured soil runoff, soil detachment, soil structure maintenance and soil macrofauna for 2.5 years under different managements of logging residues and the use or not of a legume cover crop. The results showed that the restitution of logging residues has reduced runoff by 6 and soil losses by 14 compared to plot without logging residues, over the study period. The planting line where soil is kept bare was by far the most critical area in term of soil erosion. The restitution of logging residues significantly improved soil structure maintenance as well as soil macrofauna diversity. We found strong relationships between runoff, soil losses, soil structure and soil macrofauna diversity. These results evidence that the restitution of logging residues and the sowing of cover crop are appropriate agroecological practices in young rubber plantations. Our results suggest that keeping a cover in the planting line could be the most relevant lever to limit soil erosion in the context of the study.
Sediment phosphorus stock shows a shift at the river – floodplain interface, accompanied by high vegetation biodiversity
Authors: Pucher Matthias , Bondar-Kunze Elisabeth , Hein Thomas
Published: March 2022

Floodplains can contribute enormously to nutrient reduction in streams. The phosphorus cycle at the aquatic–terrestrial interface is driven by hydrology and vegetation. Our aim was to assess conditions relevant to the phosphorus cycle prior to a floodplain restoration. The phosphorus cycle was studied by means of measuring several phosphorus fractions and adsorption/desorption experiments using floodplain soil and river sediment. The study area was located at the Mulde River near Dessau, Germany, and covered different inundation patterns, vegetation and reaches with or without embankment. A shoreline ecotone was identified by means of high vegetation biodiversity with a distinct plant community. In the ecotone, the P cycle was influenced by accumulation of relatively high bioavailable P in the soil (equilibrium phosphate concentration, EPC0) and reduction of the soluble reactive phosphorus (SRP) concentration in the pore water. Both suggested a high productivity of the vegetation. The ecotone also acted as a delineation between the stream sediments with low organic matter and inorganic P and the floodplain soil with high organic matter and inorganic P. Additionally, the study demonstrated a lower SRP concentration and EPC0 in the parts of the floodplain without bank fortification.

Since floodplains were considered ecotones before, we identified another ecotone at another scale, i.e. between floodplain and river. The ecotone does not only show the area with a favourable ratio of disturbance and resource availability but also acts as a location for biogeochemical exchange processes between rivers and floodplains. The identified shoreline ecotone offered a habitat for a specifically diverse vegetation, which itself influenced the P cycle by high biological turnover. As a highly biogeochemically active part of the floodplain, the shoreline ecotone could help in mitigating high nutrient loads in anthropogenically impacted water sheds and provide a habitat for diverse vegetation.
Magnetic properties of Baltic Sea ferromanganese concretions
Authors: Wasiljeff Joonas , Salminen Johanna , Virtasalo Joonas
Published: March 2022

Ferromanganese concretions are abundant in many parts of the coastal Baltic Sea and hence provide an important yet underused archive to investigate these shallow sea areas in detail. Coastal sea areas can be best described as filters, and they have a focal role in the biogeochemistry of riverine nutrients and suspended particles during their transport to open sea. Colloidal iron and manganese oxyhydroxides, originating from the surrounding catchment area and/or from adjacent anoxic sediments, accumulate and ultimately lead to the authigenic formation of ferromanganese concretions at an unusually fast growth rate, generally in low-carbon environments with limited sedimentation. The porous concretions come in various sizes and shapes, and host diverse microbial communities with reductive and oxidative metabolisms that can affect both the concretion growth and dissolution. Despite that, the specific formation mechanisms and (bio)mineralization processes of different concretion morphotypes are poorly constrained.

We have investigated the magnetic properties of Baltic Sea ferromanganese concretions of different morphotypes, depositional environments, water depths and geographical locations. While the magnetic mineral concentrations change according to salinity and water depth, the concentrations are also seemingly controlled by the concretion morphotype. Preliminary results of laboratory remanences also indicate the magnetic mineral assemblages are dominated by SD-sized ferrimagnetic particles with magnetic properties similar to those of magnetosomes. The possible presence of magnetotactic bacteria within the concretions provides novel insights into the biogeochemistry of low sediment accumulation and low-carbon coastal environments of the Baltic Sea.

This research is part of the Fermaid project, funded by the Academy of Finland grant 332249.
The initiation of runoff-generated debris flow in steep carbonate catchments
Authors: Francis Oliver , Tang Hui
Published: March 2022

Debris flows are a common hazard in Alpine headwater catchments during intense convective rainstorms. These debris flows are commonly triggered by runoff entraining previously deposited sediment within the catchment. A debris flow will be initiated if rainfall exceeds the given rainfall intensity threshold. We usually define the rainfall intensity threshold as a function of storm duration (rainfall intensity-duration threshold). Above this empirically recorded threshold, the resulting surface runoff can mobilise sediment from the hillslopes and within the channel network. Thresholds are usually defined empirically for a given geographic region via monitoring of debris flow occurrence and the triggering rainfall intensity. However, direct field observations and rainfall data are sparse and noisy, and it is impossible to define rainfall thresholds when historical data are unavailable. An alternative methodology to derive rainfall ID thresholds is to use simplified physics-based model simulations. In this case, a greater understanding of the controlling factors for debris-flow activities could enable better threshold estimation in unmonitored catchments.

Here we present the initial simulation results of three different monitored catchments in the Dolomite mountains of Northeast Italy. These catchments are dominated by steep dolomite bedrock walls, which can provide large volumes of surface runoff to the catchment during rainfall. To simulate the response to rainfall in these catchments, we use the SWEHR (Shallow Water Equation & Harsine Rose) debris flow model, which we calibrate using a combination of field data and a correlation maximising framework. By focusing on the runoff response to rainfall in the catchments, we identified several key factors in the calibration of the model. The timing and magnitude of the runoff is controlled by the hydrological characteristics of the bedrock, the roughness of the catchment, the availability of sediment in the catchment, and the characteristics of the rainfall. By running multiple rainfall simulations for the catchments, we show how these factors impact rainfall ID thresholds
Satellite-derived NOx emissions over Europe from TROPOMI (Sentinel 5p)
Authors: van der A Ronald
Published: March 2022

With the inversion algorithm DECSO (Daily Emissions Constrained by Satellite Observations) we derive quantitative NOx emissions on a 5 to 20 km resolution from TROPOMI (on Sentinel 5p) observations of NO2, taking advantage of the fine spatial resolution (5 x 3.5 km) of the TROPOMI instrument. The emissions are split into 3 categories: fossil-fuel, soil and maritime emissions using detailed land use information and signatures of the seasonal cycle in the emissions. 
DECSO is a full inversion algorithm based on data assimilation of satellite observation and the Chemical-transport model CHIMERE. For the data assimilation a Kalman Filter technique is used. For the inversion no apriori information of the NOx emissions is needed and for this reason new sources can be detected. 
To assess the quality of satellite-derived NOx emissions, they are compared to satellite-derived emissions calculated with the divergence method and compared to NOx emissions of various bottom-up inventories. The divergence method has been applied on TROPOMI data for a 3 month period to derive average emissions over Europe. For bottom-up emissions we selected both the CAMS (Copernicus Atmosphere Monitoring Service) regional anthropogenic emission database and the regional emission inventory HERMES (High-Elective Resolution Modelling Emission System) for Catalonia for the intercomparison. The analysis has been done for regional totals but also focussing on specific cities and factories. Detailed results will be shown, including the spatial and temporal variation per emission category. The intercomparison of DECSO with bottom-up inventories show good agreement for regional emission totals and its spatial distribution, but at a city-scale or focussing on individual sources (factories or power plants) interesting differences are found.
Recent evolution of the greenlandic ice shelves 
Authors: Mouginot Jeremie , Millan Romain , Bjørk Anders , Jourdain Nicolas , Mathiot Pierre
Published: March 2022

In the northern parts of Greenland, which hold more than 2.7 m of sea level equivalent, the ice flows through ice shelves, as in Antarctica. These floating platforms are the vulnerable parts of the ice sheets because they are the first element in contact with the warming ocean waters. Indeed, the advection of warm, salty ocean waters beneath the ice shelves increases basal melting, which reduces the buttressing effect of the ice shelves and can, in turn, trigger an increase in ice flow into the ocean. 

 

Indeed, It has been observed that Zachariae Isstrøm in northeast Greenland is retreating and accelerating, most likely due to increased melting of the base of its ice shelf, followed by breakup. Nioghalvfjerdsfjorden, its neighbor, also shows signs of thinning near its grounding line, as does Petermann Gletscher, 800 km further west. Here we study the recent dynamic and geometric changes of all present and former ice shelves along the north coast of Greenland, namely Humboldt Gletscher, Steensby Gletscher, Ryder Gletscher, Ostenfeld Gletscher, Marie Sophie Gletscher, Academy Gletscher and Hagen Bræ.

 

We document the evolution of ice shelf surface elevation using data from the Greenland Ice Mapping Project, NASA's ICESat-½, NASA's ATM, LVIS and Ocean Melting Greenland instruments. In addition, we generate digital elevation models using stereo images acquired by ASTER for all ice shelves between 2000 and the present. For the same time period, surface ice velocity is also derived from multiple optical (Landsat-7/-8 and Sentinel-2) and radar (Sentinel-1, ENVISAT, ALOS/PALSAR, TerraSAR-X and RADARSAT) sensors. We also track thirty years of ice fronts with ASTER orthoimages and grounding line evolution with a double-difference SAR interferometry approach from a combination of ERS-½ and ESA Sentinel 1-a/b observations. We use the elevation time series to monitor the temporal evolution of the total ice shelf volume assuming hydrostatic equilibrium, and then combine them with the velocity time series to calculate basal melt rates in a Lagrangian framework. Finally, we compare our basal melt observations with CTD measurements of nearby ocean temperature and the TOPAZ4b reanalysis of Arctic ocean physics provided by Copernicus Marine Service.

 

We show that significant changes for these last floating sectors of Greenland - some still undocumented - have occurred over the past 22 years. We analyze and discuss the relationship between recent ice shelf evolution and the loss of glacier mass draining through the ice shelves and the relationship with the evolution of deep ocean temperature and the evolution of the observed basal melt rate. We conclude with the possibility of current or future destabilization -or lack thereof- of glaciers in this area of Greenland.
The combined effect of light availability and drought on survival of two forest understory herb species
Authors: Urban Josef , Matoušková Marie , Plichta Roman , Gebauer Roman , Houšková Kateřina , Vitásek Roman , Hédl Radim
Published: March 2022

Dense forest canopy influences understory microclimate by lowering the air and surface temperatures. It can mitigate the adverse effects of global climate change in forest communities. On the other hand, low light availability in dense forests is the main constraint for the understory species photosynthesis. And the resulting lack of carbohydrates may make herbs more vulnerable to increasing drought induced by climate change. Here we assessed the survival and ecophysiology of two morphologically similar but physiologically rather contrasting perennial herbs typical of temperate forest understories: isohydric Asarum europaeum and relatively anisohydric Hepatica nobilis. We emulated a summer drought period by growing adult plants of these two species in the greenhouse under 10% (simulating sparse forest) and 1% (simulating dense forest canopy) of outdoor light. Half of the individuals were subjected to water stress by withholding the watering until ca 50% mortality occurred. After the drought phase, we fully watered the plants and let them recover for one month.

The lowest predawn water potential measured during the experiment was -3.6 MPa, and the midday water potentials of plants in the sun were -5.4 and -8.1 MPa for Asarum and Hepatica, respectively. Light saturated photosynthesis (Asat) of fully watered herbs was by more than 50% higher in the Asarum than in Hepatica at the end of the experiment. The two herbs plastically adjusted their Asat to the light environment, so that Asat of shaded Hepatica was by 38% and of shaded Asarum by 29% lower than in controls. After the period of drought, Asat of stressed plants of both species grown in the lighter conditions fully recovered. In the shaded variant, however, only Asat of Hepatica recovered but that of Asarum did not. Intrinsic water use efficiency (WUEi) was higher in isohydric Asarum than in Hepatica. WUEi was also higher in the herbs grown in light than in the shade. Specific dyeing to functional xylem indicated a higher proportion of conductive xylem (which means less damage by embolism) in plants grown in shade than in the light, in both species. To sum up, sufficient light may help some understory species to recover from severe water stress.
Integrated numerical modeling of microplastic transport in fluvial systems
Authors: Dichgans Franz , Boos Jan-Pascal , Frei Sven , Fleckenstein Jan H.
Published: March 2022

Although rivers and streams are major transport vectors of microplastics into the marine environment, little research has been conducted to understand the transport behavior of microplastic particles in fluvial systems. This work contributes to the understanding of these transport processes, specifically focusing on the interface of the surface water flow and the hyporheic zone.

Transport of microplastic particles in fluvial systems is currently modeled mainly at larger, river- or basin-wide scales using existing hydrodynamic and sediment transport models. To investigate the transport behavior of microplastic particles along the interface between the hyporheic zone and the open water flow domain, smaller-scale models are required so that the complex processes in this region can be adequately represented and analyzed.

To this end, a novel modeling technique will be presented based on the open source CFD toolbox OpenFOAM. It combines a new coupling approach for the hydrodynamic processes in the surface water and hyporheic zone with transport modeling of microplastics.

The methodology considers the latest findings regarding deposition and resuspension of microplastic particles as well as the hyporheic exchange in a fully coupled model. The model is validated by accompanying flume experiments and relevant transport processes are identified from the presented scenario simulations.
Non-linearity in the extratropical teleconnection to ENSO and the QBO
Authors: Walsh Amber , Screen James , Scaife Adam , Smith Doug
Published: March 2022

Modes of climate variability that remotely alter the northern hemisphere stratospheric polar vortex state are explored using the Hadley Centre Climate Model (HadGEM3). Experiments are performed that sample combinations of El Niño—Southern Oscillation (ENSO) and quasi-biennial oscillation (QBO) states. These modes were chosen as El Niño and QBO easterly phases are known to weaken the polar vortex.

The El Niño induced weakening of the polar vortex is found to be more pronounced during QBO easterly than QBO westerly. Likewise, the polar vortex weakening caused by QBO easterly is stronger during El Niño than during neutral ENSO conditions.

It is also found that El Niño induces a change to the QBO itself, namely an increase in the descent rate of the QBO, but this is not large enough to explain the nonlinear response of the polar vortex. Other possible mechanisms are investigated, such as whether the QBO and ENSO teleconnections to the polar vortex are sensitive to the prior state of the polar vortex. Impacts of this nonlinearity on the surface response are also explored.
The role of bacterial biodegradation for atmospheric budgets of formic and acetic acids
Authors: Nuñez Lopez Leslie , Ervens Barbara
Published: March 2022

Formic and acetic acids are ubiquitous components in the atmospheric gas and condensed (clouds, particles, fogs) phases. They originate from various anthropogenic or biogenic sources.

Their production and loss processes in the atmosphere are usually assumed to occur by chemical oxidation processes only. In atmospheric models, their chemical formation and loss processes are described by oxidation reactions with abundant oxidants (e.g., OH, NO3 radicals).

However, lab and model studies suggest that bacteria can efficiently biodegrade these acids and similar organic compounds. Their highest metabolic activity of bacteria is thought to be limited to their time in warm clouds due to the presence of liquid water.

 

We use a process model with detailed descriptions of cloud microphysics, multiphase (gas/cloud) chemistry and biodegradation processes in individual cloud droplets. The model is initialized with data from the Puy de Dome observatory (Auvergne, France), where long-term data sets of chemical, microphysical and biological cloud data in a variety of air masses were collected.

The model description of the multiphase chemistry and cloud microphysics is based on well-established models. Bacterial processes are implemented using lab-derived biodegradation rates for various atmospherically relevant bacteria strains and conditions.

 

We perform model studies for a variety of cloud chemical, biological and microphysical parameter ranges to identify atmospheric conditions, under which biodegradation represents a major loss process of formic and acetic acids. Since the number of bacteria cells is much smaller than that of cloud droplets, we will discuss the importance of the accurate model representation of cloud droplet properties (number concentration, diameter, lifetime) for model results. 

Our study demonstrates that microbiota in the atmosphere interact with chemical compounds and affect their budgets. It shows the need to (i) extend current atmospheric chemistry models and (ii) provide information on microbiota distribution and activity.  Thus, our work represents a study at the interface of atmospheric sciences and biogeochemistry and gives new research perspectives for interdisciplinary efforts in these fields.
Probability mapping for bedrock occurrence on the Irish Continental Margin: Applications for regional bedrock outcrop and habitat mapping 
Authors: Recouvreur Audrey , Wheeler Andrew , Strachan Ruaihri , Meere Patrick , Unitt Richard , Lim Aaron
Published: March 2022

The Irish continental margin hosts many complex sedimentary basins, and diverse geomorphological domains displaying bedrock outcrops that can host a large variety of habitats from shallow to cryptic fauna. More recent surveying in the Irish offshore territory has indicated extensive areas of bedrock exposure. The BeTar_Drill2 (Bedrock Target analysis for ROV RockDrill sampling) project applies novel bedrock suitability mapping to the full Irish continental margin (ICM); to determine potential habitat areas from shallow to deep domains for the entire ICM; to ground truth this mapping with petrographic analysis of physical samples correlated to existing seismic data. The project’s overall aim is to improve the appraisal of the regional geology and habitat mapping of the Irish margin. 

This study has improved the Bedrock Suitability Index (BSI) previously developed for the Porcupine Bank Canyon by fine tuning the variables to the wider margin. The improved BSI model has been constructed across the southern Irish continental margin, covering more than 140,000 km2, producing a high resolution (25m2) model of predictive bedrock outcrop locations. Validation by video observations and correlations of predicted bedrock exposures has established an appropriate level of confidence with BSI accuracy. The BSI mapping reveals a strong structural control on bedrock outcrop occurrence, with BSI correlating with deep structural fabrics of the margin as expressed by fault lines. 
Simulating the impact of creep in natural consolidation and subsidence in depositional environments
Authors: Xotta Riccardo , Minderhoud Philip S. J. , Zoccarato Claudia , Teatini Pietro
Published: March 2022

Depositional landforms, such as tidal marshes and deltas, formed by sediment deposition over the last centuries to millennia. They are complex, vulnerable, and dynamic systems with important roles from environmental and human points of view. The survival of these lowlying landforms is threatened by multiple stressors, e.g. sea level rise and reduction in sediment supply. In addition to these external factors, natural compaction of the sedimentary bodies may have an important role on the elevation dynamics because of the large porosity and compressibility that characterize the shallow deposits. A three-dimensional (3D) finite element simulator (NATSUB3D) has been recently developed to model the long-term dynamics of transitional landforms. The model couples a 3D groundwater flow module to compute over-pressure dissipation with a 1D compaction module based on the elasto-plastic Terzaghi theory. NATSUB3D properly accounts large deformations thanks to an accreting/compacting mesh that follows the grain movements (Lagrangian approach). The NATSUB3D formulation is updated to account for viscous deformations using the NEN-Bjerrum constitutive relationship. Indeed, creep may represent an important process in fine unconsolidated deposits forming Holocene coastal landforms. With the new constitutive model, soil deformation is effective stress and time dependent. The new simulator has been applied on 1D synthetic cases mimicking long-term accretion of sedimentary columns. Hydro-geomechanical properties typical of sediment classes composing depositional landforms are used. A sensitivity analysis has been performed on sedimentation rates and secondary compression coefficients, which are the main parameters affecting the viscous deformation, leading to significantly different elevation dynamics. In the simulation of these processes (i.e., the formation of a sedimentary landform), the overconsolidation ratio (OCR), which is the geomechanical parameter most difficult to quantify and highly impacting soil compaction, can be simply set equal to 1 for the newly formed soil layer. Indeed, OCR is then properly updated by the model itself because the simulation follows the soil deformation since time of sediment deposition, with soil experiencing compaction because new sedimentation occurs on the landform top.
A severe landslide event in the Alpine foreland under possible future climate and land-use changes
Authors: Maraun Douglas , Knevels Raphael , Mishra Aditya N. , Truhetz Heimo , Bevacqua Emanuele , Proske Herwig , Zappa Giuseppe , Brenning Alexander , Petschko Helene , Schaffer Armin , Leopold Philip , Puxley Bryony L.
Published: March 2022

Landslides are a major natural hazard, but uncertainties about their occurrence in a warmer climate are substantial. The relative role of rainfall, soil moisture, and land-use changes and the importance of climate change mitigation are not well understood.  Here, we develop and apply a storyline approach to address these issues, considering a severe event from June 2009 in Austria with some 3000 landslides as showcase. The approach leverages on convection permitting simulations that realistically represent the meteorological event while sampling uncertainties.  Depending on the changes of rainfall and soil moisture, the area affected during a 2009-type event could grow by 45% at 4 K global warming, although a slight reduction is also possible. Such growth could be reduced to less than 10% by limiting global warming according to the Paris agreement. Anticipated land-use changes towards a climate resilient forest would fully compensate for such a limited increase in hazard.
Towards an automated monitoring solution of pollen concentrations using light scattering properties 
Authors: El azari Houssam , Renard Jean-Baptiste , Bleza Esso-Ridah , Lauthier Johann , Richard Jérôme
Published: March 2022

The monitoring of airborne pollen concentrations has become of a crucial importance over the past decades, as the number of allergy sufferers is continuously increasing and the symptoms becoming more severe due to pollution and climate change.  The historical method usually used to identify pollen species present in the air and quantify them is manual with limitations such as a delay in pollen information availability and a high operational cost.

Here, we introduce a new automated solution aimed at identifying pollen grains and evaluating their concentrations based on their light scattering properties. More specifically, we introduce a low-cost and real-time optical pollen sensor named Beenose, which performs measurements at multiple scattering angles. We present an analysis of the data obtained in laboratory and the first results of the validation campaign in comparison with the historical method. Laboratory measurements were first conducted by inserting aerosols including carbonaceous particles, droplets, and different pollen species into the instrument. The collected data were then pre-processed to extract reference speciation indexes, which were used to train classification algorithms and to perform pollen identification outdoor. The results are promising and demonstrate the ability to correctly recognise some pollen species and to differentiate them from carbonaceous and droplets. In particular, among 24 species of interest, 9 are classified with an accuracy above 80%. Additionally, the total airborne pollen concentrations recorded by Beenose and the historical method are consistent. Finally, we discuss the remaining challenges to achieve a robust monitoring of the concentrations per specie and how to improve the identification of the pollen species having a similar optical behaviour.
Characterising reanalysis representation of winds at the interface between Antarctica and the Southern Ocean
Authors: Caton Harrison Thomas , Bracegirdle Tom , King John , Biri Stavroula
Published: March 2022

Low-level easterly winds encircle Antarctica, helping drive coastal currents which modify transport of circumpolar deep water to ice shelves as well as the formation and distribution of sea ice. Semi-permanent katabatic winds interact with a highly variable maritime component associated with synoptic forcing, both of which are influenced by the steep orography of the Antarctic margins. In this research, representation of the terrestrial and maritime components of the easterlies in three state-of-the-art reanalyses (ERA5, MERRA2 and JRA55) is evaluated. Variability on daily timescales is analysed using self-organising maps which objectively cluster coastal flow regimes into states with different synoptic and mesoscale influences. Correlation coefficients with station and sonde observations are highest in ERA5 overall but stronger terrestrial winds in MERRA2 and JRA55 reduce biases relative to ERA5 for many states. ERA5 is the least prone to overestimating low wind speeds. Performance is reduced for all reanalyses during states dominated by terrestrial katabatics and at stations near sloping terrain. Wind speeds are consistently underestimated when cyclone activity near the steep coastal orography drives a super-geostrophic low-level jet. These results demonstrate how a characterisation of coastal wind variability on short timescales could help diagnose errors in coarser models used for future projections.
Remote sensing versus surveyed object-based cadastre data: Comparing the advantages of COPERNICUS imperviousness density and ATKIS data in Bavaria/Germany using GIS analysis
Authors: Mitterer Johannes , Disse Markus
Published: March 2022

As the built-up areas extend and become denser with time, high-resolution land use and especially imperviousness data is of increasing importance, e.g., for detailed studies on settlement and landscape water retention to provide for extremes such as (flash) floods, heatwaves, and droughts.

The open-source COPERNICUS imperviousness density dataset covers 2006 until 2018 with a three-year timestep with incremental raster resolution (2018: ten meters). On the other hand, there is an accurate object-oriented cadastre dataset of German authorities called ATKIS. It describes the geometries of buildings and all types of traffic routes from airports to dirt roads with an increasing amount of attributes like shape, area, width, or material. While both datasets are very detailed, they have specific (dis-)advantages due to their very different data and surveying type.

We used the information stored in the ATKIS database of 2020 to create an alternative object-based imperviousness map of the German state Bavaria with roughly 70,000 km² to contrast and compare it with the COPERNICUS imperviousness density dataset of 2018 in several different (urban and rural) areas. We found that COPERNICUS indicates much higher imperviousness for densely settled areas as city centres and commercial and industrial zones and can describe even complex types of significant extent (such as golf courses, transhipment stations, and allot settlements) better. Vice versa, ATKIS could resolve even linear traffic elements in rural areas and detached house settlements to an outstanding level of detail, which COPERNICUS cannot afford due to its limited resolution. Both products cannot distinguish clearly between sealed concrete and loose stony material (e.g., from construction or mining sites), nor give indications on sub-surface water retention or sewage infrastructure.

Overall, we can name both methods' (dis-)advantages, relate them to surprisingly distinct land use classes, and give guidance, where additional object-oriented information can significantly improve COPERNICUS imperviousness data. Finally, the resulting maps highlight the hotspots of extreme building-independent imperviousness. They can serve as a tool to prioritize areal and building-centred measures to prevent large amounts of fast runoff.
3D evolution of extensional detachment faults and their effect on the architecture of rifts and rifted margins
Authors: Osmundsen Per Terje , Péron-Pinvidic Gwenn , Gresseth Julie Linnea , Braathen Alvar
Published: March 2022

Extensional detachment faults, core complexes and supradetachment basins play major roles in the evolution of 3D rifted margin architecture. The successive incision of basement from early to late stages in the margin evolution is rarely explained in 3D. One reason for this is likely the lack of a unifying model for how very large faults grow and link laterally, and how this, in turn, links to the temporal evolution of the margin. As fault shape exerts a fundamental control on syn-rift basin architecture, the 3D evolution of detachment faults is critical to understand sedimentation in associated basins.

In the proximal margin offshore Norway, one control on lateral variation appears to be the differential exploitation of `extraction´ structures that evolved above the ductile crust. This controlled flips in fault polarity under the proximal margin, and lateral transitions from supradetachment- to half-graben style, Late Paleozoic-Triassic basins. Extensional culminations and core complexes were associated with this deformation pattern at depth.

The growth of an extensional fault past a displacement of a few kilometers will involve a change in 3D fault shape related to the isostatic rollback of parts of the fault plane. As displacement magnitude varies along the fault plane, so will the amount of extensional unloading and associated isostatic compensation. With increasing extension this will enforce a particular shape on the fault plane, with an extensional culmination developing in the area of maximum displacement, and synclinal recesses evolving on the flanks. With continued extension, the culmination evolves into a core complex. Necking domains, where faults propagate into the ductile middle crust appear to be prime locations for this type of faulting. As large-magnitude faults combine into domain-bounding breakaway complexes, this results in intermittent occurrences of core complexes along the main breakaways and lateral transitions into steeper megafaults and fault arrays. At the Mid-Norwegian margin, we interpret the Jurassic-Cretaceous North Møre and south Vøring basins to illustrate this type of evolution. Components of strike-slip may modify this type of pattern, as illustrated by  continental core complexes exposed in areas such as Death Valley and western Norway.

 
Comparison of rainfall retrieval from collocated commercial microwave links with adjusted radar reference
Authors: Špačková Anna , Fencl Martin , Bareš Vojtěch
Published: March 2022

One of the pivotal variables in the hydrological system processes is precipitation. In this context, many hydrological applications require a reliably captured structure and temporal development of rainfalls. Therefore, the crucial challenge is to monitor rainfall in high spatial and temporal resolution. The opportunistic sensors for rainfall measurements have a great potential since they can complete standard observation networks with high number of alternative measuring sensors. Nowadays, one of the most prominent opportunistic source of rainfall information are telecommunication networks composed of commercial microwave links (CMLs). CMLs can supply dense path-averaged rainfall information derived from power-law relationship of the microwave signal attenuation and the rainfall intensity.

However, the actual implementation and employment requires a careful consideration of the errors and uncertainties of the measurements. In this study, the influence of different state of the rainfall is excluded using the set of pairs of collocated independent CMLs with paths in the immediate vicinity. Therefore, each pair of collocated CMLs can be assumed as identically influenced by the same rainfall conditions, while their characteristics (e.g., lengths, frequencies, polarizations) vary. The dataset consists of 33 rainfall periods within the years 2014 – 2016 monitored by 13 groups of collocated CMLs.

High correlation (around 0.95) was found for collocated CMLs. Compared to conventional rainfall sensors, for example, Peleg et al. (2013) demonstrated a correlation of 0.92 for collocated tipping bucket rain gauges. The CMLs are also compared with the adjusted weather radar rainfall information which is used as a reference. The dispersion of the data within five intensity ranges was used to set the boundaries (5 % and 95 % quantile). Subsequently, the fit of the CML measurements into the boundaries was examined. CMLs with 0.2 dB/mm/h sensitivity had the highest fit ratio, almost 80 %. Contrastingly, sensors with sensitivity 1.5 dB/mm/h just exceeded the fit ratio of 60 %. Observed differences describe the uncertainties which are not directly driven by the propagation of the signal. The uncertainties of CML need to be further studied to maximize the knowledge-based use of the favourable spatial and temporal resolution of this opportunistic sensing network.

References
Peleg, N., Ben-Asher, M., and Morin, E. (2013) Radar subpixel-scale rainfall variability and uncertainty: lessons learned from observations of a dense rain-gauge network, Hydrol. Earth Syst. Sci., 17, 2195–2208, https://doi.org/10.5194/hess-17-2195-2013.

This study is supported by the project SpraiLINK (20-14151J) of the Czech Science Foundation and by the grant of Czech Technical University in Prague no. SGS21/052/OHK1/1T/11.