bluuebunny/crossref_metadata_2025 huggingface dataset:
Constructing Mediterranean wetland open water dynamics using a new 18-year MODIS-derived surface water fraction dataset
Authors: Li Linlin , Vrieling Anton , Skidmore Andrew , Wang Tiejun
Published: March 2020

Wetlands are among the most biodiverse ecosystems in the world, due largely to their dynamic hydrology. Frequent observations by satellite sensors such as the Moderate Resolution Imaging Spectrometer (MODIS) allow for monitoring the seasonal, inter-annual and long-term dynamics of surface water extent. However, existing MODIS-based studies have only demonstrated this for large water bodies despite the ecological importance of smaller-sized wetland systems. In this paper, we constructed the temporal dynamics of surface water extent for 340 individual water bodies in the Mediterranean region between 2000 and 2017, using a previously developed 8-day 500 m MODIS surface water fraction (SWF) dataset. These water bodies has a wide range of size, specifically 0.01 km2 and larger. We then compared the water extent time series derived from MODIS SWF with those derived from a Landsat-based dataset. Results showed that MODIS- and Landsat-derived water extent time series showed a high correlation (r = 0.81) for more dynamic water bodies. Our MODIS SWF dataset can also effectively monitor the variability of very small water bodies (<1 km2) when comparing with Landsat data as long as the temporal variability in their surface water area was high. We conclude that MODIS SWF is a useful product to help understand hydrological dynamics for both small and larger-sized water bodies, and to monitor their seasonal, intermittent, inter-annual and long-term changes.
On the necessity of non-hydrostatic pressure models for free surface flow over complex topography
Authors: Echeverribar Isabel , Brufau Pilar , García-Navarro Pilar
Published: March 2020

There is a wide range of geophysical flows, such as flow in open channels and rivers, tsunami and flood modeling, that can be mathematically represented by the non-linear shallow water 1D equations involving hydrostatic pressure assumptions as an approximation of the Navier Stokes equations. In this context, special attention must be paid to bottom source terms integration and numerical corrections when dealing with wet/dry fronts or strong slopes in order to obtain physically-based solutions (Murillo and García-Navarro, 2010) in complex and realistic cases with irregular topography. However, although these numerical corrections have been developed in recent years achieving not only more robust models but also more accurate results, they still might find a limit when dealing with specific scenarios where vertical information or disspersive effects become crucial. This work presents a 1D shallow water model that introduces vertical information by means of a non-hydrostatic pressure correction when necessary. In particular, the pressure correction method (Hirsch, 2007) is applied to a 1D finite volume scheme for a rectification of the velocity field in free surface scenarios. It is solved by means of an implicit scheme, whereas the depth-integrated shallow water equations are solved using an explicit scheme. It is worth highlighting that it preserves all the advantages and numerical fixes aforementioned for the pure shallow water system. Computations with and without non-hydrostatic corrections are compared for the same cases to test the validity of the conventional hydrostatic pressure assumption at some scenarios involving complex topography.

[1] J. Murillo and P. Garcia-Navarro, Weak solutions for partial differential equations with source terms: application to the shallow water equations, Journal of Computational Physics, vol. 229, iss. 11, pp. 4327-4368, 2010.

[2] C. Hirsch, Numerical Computation of Internal and External flows: The fundamentals of Computational Fluid Dynamics, Butterworth-Heinemann, 2007.
CITRAM - Citizen Science for Traffic Management
Authors: Gräler Benedikt , Doll Christoph , Mück Jürgen , Remke Albert , Schramm Diana , de Wall Arne , Wulffius Herwig
Published: March 2020

The CITRAM project aims at improving traffic quality in cities with the help of floating car data provided by citizens. During CITRAM, the citizen science platform enviroCar (https://www.enviroCar.org) has been extended and is used to collect floating car data in three German cities. Citizens are invited to collect data in designated field tests while driving their day-to-day routes. These collected trajectories are anonymised, stored and published under an open data policy in a central server.

Dedicated postprocessing services using new concepts for evaluation and visualization analyze the data on a daily basis deriving traffic quality characteristics. The raw data and the processed reports are used by the cities and their planners to assess the traffic quality and to deduce actions to improve traffic management.

The project also raises the awareness of an environmentally improved driving behavior through the collection of floating car data enriched with individual energy and fuel consumption along the recorded routes of electric and internal combustion engine driven cars. Through the integration of municipal information infrastructure into a dedicated real-time Smart City platform and a model accounting for the dynamic control of traffic light systems, a traffic light phase assistant app (ECOMAT) further supports the driver in a foresighted and energy optimized driving behavior by providing Green Light Optimised Speed Advisory (GLOSA) and Time To Green (TTG) information in real-time.

The motivation of CITRAM is the coupling of system components that enable scientists, traffic engineers and citizens to collaborate on knowledge acquisition concerning driving in motorized traffic. We will present the developed tool set and the results from the analysis of floating car data collected by citizens. The analysis assess the quality of traffic flow within the municipality as well as characteristics of individual trajectories or dedicated routes.
Beach wrack as a potential natural resource in the South-Eastern Baltic
Authors: Gorbunova Julia , Chubarenko Boris
Published: March 2020

Beach wrack (BW) – biological marine materials as algae, sea grasses and other, which are thrown from the sea to the seashore, becoming a polluter and cause of inconvenience. Problem of BW is present in the Kaliningrad Oblast of Russia, South-Eastern Baltic. From time to time, large amounts of BW appear in various places along its seashore. However, BW can be used as an organic resource, so nuisance could be converted into resource and asset. The study on BW spatial and quantitative distribution and its potential use in the South-Eastern Baltic is carry out within the Project #R090 CONTRA of the Interreg Baltic Sea Region Programme and accompanied by researches of algae species composition basing on partly support of the State assignment of IO RAS (Theme No. 0149-2019-0013).

An observations of the Baltic seashore within the Kaliningrad Oblast was carried out in March-December 2019 with the aim of quantity and quality characteristic of BW emissions. The BW emissions were recorded (measured, described and geo-referenced using GPS navigation) and sampled on two model sites monthly and the alongshore survey was carried out seasonally. Monitoring of the time of residence of the BW emissions was carried out three times per day at the selected model site using a web camera. It was found that the distribution of BW was characterized by significant spatial and temporal variability. In general, large amounts of BW emissions were observed on the northern coast of the Sambian Peninsula, in contrast to the western coast and Curonian and Vistula spits. The largest accumulations of BW were local and mainly near the coastline protrusions as capes (natural) and breakwaters, slipways, bunes (man-made). The time of residence of BW storage varied greatly and was often limited to a few days. Their further transformation could be carried out in several ways - by flushing back to the sea, covering under the thickness of sand or small pebbles, and a wind-wave dispersal along the beach. BW mainly contains Radophyta algae in the early spring and autumn-winter periods, in contrast to summer, when there are also Chlorophyta and Phaeophyta.

The preliminary estimations show that the industrial use of BW is limited by the spatial and temporal irregularity of their emissions in the Kaliningrad Oblast. However, the problem of BW collection and utilization exists. A possible solution could be use of BW for coastal protection greenery as nutrients that is similar to a natural process. These experiments were initiated in the Curonian Spit National Park in 2019. In this way BW could be involved in soft engineering techniques to manage the coastline.
Combined use of geostatistical and conceptual hydrological models for a preliminary assessment of “undercatch” of precipitation in The Canales Basin (Sierra Nevada, Spain).
Authors: Jimeno-Sáez Patricia , Collados-Lara Antonio Juan , Alvarado-Montero Rodolfo , Pulido-Velazquez David , Pardo-Igúzquiza Eulogio , Senent-Aparicio Javier
Published: March 2020

Gauges modify wind fields, producing important undercatch in solid precipitation.  For this reason, solid precipitation measurements show significant bias with respect to real values, especially under windy conditions. In this work we propose a methodology that combines geostatistical and hydrological models to perform a preliminary assessment of global undercatch and precipitation patterns (distribution between solid and liquid phase and spatial gradient with elevation) in alpine regions. It is based on the available information about daily natural streamflow and daily climatic data (precipitation and temperature) in the catchment. We want to analyse long time periods in order to take into account the stochastic behaviour of natural streamflow and climatic variables. A preliminary assessment of temperature and precipitation fields is performed by applying various geostatistical approaches assuming some hypothesis about the relationship between climatic fields and altitude. The generated fields are then employed as inputs of conceptual hydrological models, which includes two parameters to correct the solid and liquid precipitation, respectively. We have considered different hydrological approaches (SRM, HBV and a Témez model with a simple degree-day approach). The parameters are calibrated by minimizing the difference between the simulated and historical natural streamflows and/or snow cover area. It allows us to identify the best combination of geostatistical and hydrological models to approximate streamflow, to perform a global preliminary assessment of the undercatch of solid and liquid precipitation and their precipitation patterns by analysing spatial gradients with elevation. The methodology was applied in the Canales Basin, an alpine catchment of the Sierra Nevada (Spain).

This research has been partially supported by the SIGLO-AN project (RTI2018-101397-B-I00) from the Spanish Ministry of Science, Innovation and Universities (Programa Estatal de I+D+I orientada a los Retos de la Sociedad) and by the GeoE.171.008-TACTIC project from GeoERA organization funded by European Union’s Horizon 2020 research and innovation program
Catchment scale land use optimisation using genetic algorithm to mitigate acute diffuse pollution
Authors: Suslovaite Vaida , Shucksmith James , Speight Vanessa
Published: March 2020

Diffuse pollution resulting from rainfall runoff processes is known to adversely affect surface water quality, including in areas where surface water is used for drinking water supply. Designing and implementing targeted mitigation measures to reduce peak concentrations of specific contaminants such as pesticides is challenging due to the spatial and temporal variability of rainfall-runoff processes. Receiving water pollutant concentrations are a function of rainfall processes, catchment characteristics, receiving water conditions and the locations of pollution sources (i.e. spatial distribution of ‘high risk’ land use types). Past work has developed a validated, travel time based, physically distributed model used to predict metaldehyde levels after a rainfall event accounting for variations in rainfall and distribution of land use. However, targeted field scale mitigation measures require an understanding of how different land use distributions affect pollutant concentrations in river water over a representative number of rainfall events. 

In this study, an inverse modelling approach is adopted in which the metaldehyde model is used in conjunction with spatial and temporal distributions of rainfall data spanning over a number of years. Genetic algorithm(GA) technique is used to carry out land use optimisation. This technique can be used to determine distributions of land use that minimises the total number of predicted hours that metaldehyde levels exceed the EU and UK threshold of 0.1 μg L−1 for pesticides in drinking water. The approach can also be used to show how the removal of specific high risk fields will affect metaldehyde concentrations as well as rank and prioritise specific catchment areas. This can be used to inform catchment management groups of the most effective locations for the implementation of mitigation measures.
Simulation and validation of long-term ground surface subsidence in continuous permafrost, western Arctic Canada
Authors: O'Neill H. Brendan , Zhang Yu
Published: March 2020

Ground surface subsidence caused by the melt of excess ice is a key geomorphic process in permafrost regions. Subsidence can damage infrastructure, alter ecology and hydrology, and influence carbon cycling. The Geological Survey of Canada maintains a network of thaw tubes in northwestern Canada, which records annual thaw penetration, active-layer thickness, and ground surface elevation changes at numerous sites. Measurements from the early 1990s from 17 sites in the Mackenzie Delta area have highlighted persistent increases in thaw penetration in response to rising air temperatures. These increases in thaw penetration have been accompanied by significant ground surface subsidence (~5 to 20 cm) at 10 ice rich sites, with a median subsidence rate of 0.4 cm a-1 (min: 0.2, max: 0.8 cm a-1). Here we present preliminary results comparing these long-term field data to simulations for two observation sites using the Northern Ecosystem Soil Temperature (NEST) model. NEST has been modified to include a routine that accounts for ground surface subsidence caused by the melt of excess ground ice. The excess ice content of upper permafrost in the simulations was estimated based on ratios between thaw penetration and subsidence measured at each thaw tube. The NEST simulations begin in 1901, and there is little ground surface subsidence until the 1980s. The simulated rate of ground surface subsidence increases in the 1990s. The modelled ground surface subsidence is in good agreement with the measured annual magnitudes and longer-term patterns over the measurement period from 1992 to 2017. This preliminary assessment indicates that the modified NEST model is capable of predicting gradual thaw subsidence in ice-rich permafrost environments over decadal timescales.
The Holocene landscape sensitivity of the central Bavarian Jura foothills towards climatic and human influences
Authors: von Suchodoletz Hans , Kopecky-Herrmanns Britta , Berg Stefanie , Schneider Birgit , Fülling Alexander , Zielhofer Christoph
Published: March 2020

There is an ongoing debate about the main drivers of the Holocene landscape dynamics in Central Europe, i.e. when and where these were dominantly controlled by climatic (e.g. rapid climate changes) or anthropogenic factors. Investigations of colluvial and fluvial deposits are ideal to contribute to this discussion, given that the formation of colluvial deposits in Central Europe is often controlled by human activity, whereas the formation of alluvial deposits might be more influenced by climatic fluctuations.

In the forefront of a road construction intercalated colluvial and fluvial sediments with thicknesses up to 4 m were outcropped and studied during archaeological excavations led by the Bavarian State Office for Monument Conservation near Dettenheim in central Bavaria (southern Germany) in 2015. This investigated site is located next to the Fossa Carolina (Karlsgraben), a canal that was built at the end of the 8th century AD to bridge the watershed between Rhine and Danube but that was never finished. We investigated the sediments using sedimentological, archaeological and geochronological (OSL) methods. After a period with fluvial activity during the Early Holocene, the landscape was mostly stable between ca. 10 and 2.5 ka, allowing the formation of soils. Although human activities next to the investigated sites originate from the Hallstatt period, the first interruption of the stable period only occurred during the La Tène Period when fluvial and colluvial deposits were formed. Subsequently, intensive colluviation occurred during the Migration Period/Early Middle Ages, followed by intensive colluvial and fluvial deposition that started since the High Middle Ages and continues until today. Our investigations indicate that human disturbance obviously led to an intensive landscape degradation during the La Tène Period, and the landscape was subsequently much more sensitive towards human and climatic fluctuations than before.
Multiphase tectonic interaction of Tyrrhenian - Tunisia Margin - Ionian systems: Implications for regional seismogenesis
Authors: Ranero César R. , Gracia Eulalia , Sallares Valenti , Grevemeyer Ingo , Zitellini Nevio
Published: March 2020

The region at the transition from the west to the east Mediterranean is a complex puzzle of terrains spanning in age from the Mesozoic Ionian lithosphere to the Pleistocene arc and back arc domains of the Tyrrhenian system. Although the region has had a complicated evolutionary history, the current configuration of terrains fundamentally denotes Miocene to recent kinematics.

In this contribution we present new data from Tunisia Margin showing the evolution from its formation in early Miocene to recent, the tectonic interaction with the opening of the Tyrrhenian system and its current inversion, and discuss the implications for the regional kinematics evolution.  

The Tyrrhenian is no longer extending, but all basin borders indicate currently active large-scale thrusting  to strike slip tectonics. Tunisia margins formed by a well-know contractional tectonic phase in early Miocene expressed in large-scale tectonics with a clearly imaged thrust  and fold belt, cut by Messinian to Pliocene extensional faulting. However, high resolution multibeam bathymetry and images of the shallowest layers indicates ongoing inversion tectonics.

We compare the tectonic evolution of north Tunisia and Tyrrhenian with the patterns of deformation of the Ionian tectonic wedge observed in new and reprocessed seismic images. We interpret the current deformation of the Ionian tectonic wedge based on the integration of evolution of the kinematics from the data sets of observations from the three systems.

We conclude that the entire region is currently under collision of the Africa Plate with the Adria Plate and the Neogene terrains of the Tyrrhenian Domain.  The corollary is the subduction of the Ionian lithosphere is fundamentally stalled so that the megathrust fault is possibly not any longer accumulating significant shortening and most deformation is currently occurring in steeper faults re-activation or cutting the previous structural framework.
Urban-Nexus: Dependency of urban agglomeration, Hyderabad, India, on external water resources in developing economy.
Authors: Dagani Koteswara Rao , Regonda Satish Kumar
Published: March 2020

Self-sufficiency in water, food, and energy become major concerns of cities in the global urbanization era. To reach the self-sufficiency goals of cities, they depend more on external water resources, in the form of trade and imports to satisfy the water demands, which came into the focus with rapid urbanization. In this scenario, cities must measure their consumption, to know their dependence on external resources, and to draft their trade policies. But, it is tough to scale the dependency of cities on external resources at the city scale, in scarce of city-level trade data.

Here we are proposing a framework using the consumer-centric approach to scale dependency of an urban agglomeration, from consumption and production perspectives when there is no city-level trade data. In the consumption perspective, we used survey data provided by the National Sample Survey organization of India to asses the consumption footprints. In the production perspective, we used production statistics of the study area to assess the production footprints. The difference between the consumption and production WF will give the dependency of agglomeration on external resources. From the consumption perspective, the consumption WF of the study area is 1041 m3/cap/year.

This framework is flexible and can be switched between any two or more entities to know the dependency of cities on external resources for their resources. Moreover, this assessment plays a key role in trade policy decisions and also in scaling the consumption and dependency of cities to achieve self-sufficiency and sustainability goals of smart cities.
The Global Environmental Monitoring Systems (GEMS) Constellation of Passive Microwave Satellite
Authors: Porter Gregory , Delf Richard , Gasiewski Albin , Hurowitz Michael , Gallaher David , Sanders Brian , Hosack William , Kraft David , Carter Roger , Zhang Kun , Sasaki Geoffrey
Published: March 2020

The recent successful launch of the Orbital Micro Systems GEMS-1 IOD (Global Environmental Monitoring System In-orbit Demonstrator) satellite carrying the University of Colorado’s MiniRad 118-GHz imager/sounder instrument provides the basis for a new means of observing atmospheric precipitation, temperature, and related state variables. GEMS-1 supports an 8-channel passive microwave radiometer operating at the 118.7503 GHz oxygen resonance with cross-track scanning imaging system providing cross- and along track Nyquist sampling at 17 km 3dB spatial resolution. It is precisely calibrated using cold space views along with and an on board reference, yielding the first low-cost commercial weather satellite imagery. GEMS is the first of a constellation of approximately 50 such satellites of progressively improving resolution and spectral coverage that will collectively provide Nyquist time-sampling of precipitation and related weather variables on a global basis, and using microwave frequencies will provide such information probing through most cloud cover. Presented will be first light imagery and on-orbit performance data from the GEMS-1 mission, including validation data on the satellite brightness temperatures. Products will include calibrated multispectral imagery, temperature profiles, retrieved rain rate, and precipitation cell top altitude. The expansion of the GEMS-1 mission to the full GEMS constellation will be outlined.
The role of history and strength of the oceanic forcing in sea-level projections from Antarctica with the Parallel Ice Sheet Model
Authors: Reese Ronja , Levermann Anders , Albrecht Torsten , Seroussi Hélène , Winkelmann Ricarda
Published: March 2020

Mass loss from the Antarctic Ice Sheet constitutes the largest uncertainty in projections of future sea-level rise. Ocean-driven melting underneath the floating ice shelves and subsequent acceleration of the inland ice streams is the major reason for currently observed mass loss from Antarctica and is expected to become more important in the future. Here we show that for projections of future mass loss from the Antarctic Ice Sheet, it is essential (1) to better constrain the sensitivity of sub-shelf melt rates to ocean warming, and (2) to include the historic trajectory of the ice sheet. In particular, we find that while the ice-sheet response in simulations using the Parallel Ice Sheet Model is comparable to the median response of models in three Antarctic Ice Sheet Intercomparison projects – initMIP, LARMIP-2 and ISMIP6 – conducted with a range of ice-sheet models, the projected 21st century sea-level contribution differs significantly depending on these two factors. For the highest emission scenario RCP8.5, this leads to projected ice loss ranging from 1.4 to 4.3 cm of sea-level equivalent in the ISMIP6 simulations where the sub-shelf melt sensitivity is comparably low, opposed to a likely range of 9.2 to 35.9 cm using the exact same initial setup, but emulated from the LARMIP-2 experiments with a higher melt sensitivity based on oceanographic studies. Furthermore, using two initial states, one with and one without a previous historic simulation from 1850 to 2014, we show that while differences between the ice-sheet configurations in 2015 are marginal, the historic simulation increases the susceptibility of the ice sheet to ocean warming, thereby increasing mass loss from 2015 to 2100 by about 50%. Our results emphasize that the uncertainty that arises from the forcing is of the same order of magnitude as the ice-dynamic response for future sea-level projections.
The tectonic origin of Planum Boreum spiral troughs, Mars
Authors: Rossi Costanza , Cianfarra Paola , Salvini Francesco
Published: March 2020

The spiral troughs of the North Polar Layered deposits on Mars are deep depressions that dissect the Planum Boreum ice cap. These are enigmatic structures whose puzzling origin is still under debate. Advanced hypotheses on their genesis and evolution range between erosional to structural scenario. In this work, a double approach was followed to explore the structural/tectonic origin of the spiral troughs by means of Hybrid Cellular Automata (HCA) numerical modelling and lineament domain analysis. The SHARAD profile data were used to replicate the ice internal layering architecture associated to buried troughs in Gemina Lingula. Analysis of the lineament domains automatically detected at the ice surface from satellite images of the Mars Orbiter Camera strengthened the structural/tectonic interpretation of their origin and evolution. Similar, twofold approach was used for the investigation of a terrestrial analog identified in the Antarctic ice sheet. It presents at depth blind structures recognized as fractures/faults produced by ice sheet dynamics. Radargrams of Operation IceBridge mission and images from Sentinel-2 were used to produce a tectonic model that was in turn compared with the Planum Boreum one. Obtained results, and their comparison, show that the troughs of Gemina Lingula result from the activity of low-angle normal faults with listric geometry. The activity of listric faults is modelled and compared with the antarctic analog. At the surface the detected lineament domains confirm the tectonic setting by tracing the buried trough/fault orientations. The proposed tectonic model refers to extensional regime characterized by the presence of a deep detachment connecting the troughs at depth. This represents an internal ductile layer placed at depth greater than 1000 m whose kinematics induces the troughs/faults deformation. The extensional tectonics developed in Planum Boreum is possibly related to the ice cap collapse that induces internal dynamics. In this way, katabatic winds play a secondary role by maintaining at the surface the troughs nearly orthogonal to their directions.
Glaciological controls on the spatial variability of supraglacial debris extent and thickness in the eastern Himalayas
Authors: Boxall Karla , Willis Ian
Published: March 2020

Debris cover is particularly prevalent in High Mountain Asia, with SW Asia alone containing 3,264 km2 of debris-covered ice (Scherler et al., 2018), which is increasing over time (Thakuri et al., 2014). The presence of supraglacial debris alters the energy balance by either enhancing or inhibiting ablation, depending on its thickness (Östrem, 1959). Therefore, debris cover is fundamental to the response of Himalayan glaciers to climate change. However, there remains a need to understand the glaciological characteristics that control the spatial pattern of debris cover and thus how it may evolve in the future.

Previous research has explored some controls of the spatial distribution of debris cover on a glacier scale (Gibson et al., 2017; Nicholson et al, 2018), but this research will take place on a regional scale. The chosen area is a ~9300 km2 region in the eastern Himalayas that encompasses both Ngozumpa and Lirung glaciers.

The GAMDAM glacier inventory (Sakai et al. 2019) will be used to delineate the glaciers. Within each glacier, the debris extent and thickness will be determined. Extent will be estimated through the supervised classification of optical imagery, using training data obtained from high-resolution Google Earth imagery. Thickness will be calculated through the derivation of a relationship between thermal satellite data (redistributed to a finer spatial resolution) and debris thickness measurements of Lirung glacier (McCarthy et al., 2017) and of Ngozumpa glacier (Nicholson et al., 2018).

An 8m DEM (from NSIDC) will be used to calculate slope, aspect and curvature over each glacier and repeat-pass SAR acquisitions will be used to calculate the velocity field for each glacier. The statistical relationship between debris extent and thickness with each of the aforementioned glacier characteristics is the intended output. Sensitivity tests will subsequently be carried out to determine the relative influence of each glaciological characteristic.
Improved precision and throughput for 17O-excess measurements on water with Cavity Ring-Down Spectroscopy
Authors: Hofmann Magdalena E. G. , Lin Zhiwei , Doherty Thomas , Bent Jonathan D. , Lucic Gregor
Published: March 2020

Triple oxygen isotope data (denoted as 17O-excess) have been used to constrain meteorological processes, plant fractionation processes, animal metabolism, and a variety of other physical and chemical processes. Measurement precision is key in order to successfully apply this promising new tracer to a range of scientific questions. Up to date, the highest measurement precision for 17O-excess on water was achieved by converting water to O2 and subsequent mass spectrometric analysis of O2 (Barkan and Luz, 2005). This approach allows to reach a measurement precision of about 5-6permeg. However, it is very difficut to setup and only a few laboratories worldwide succesfully use this methodology. A far simpler approach is to use Cavity Ring-Down Spectroscopy (CRDS), i.e. the Picarro L2140-i analyzer that measures δ18O, δ17O, δD and determines 17O-excess. To date, the 17O-excess measurement precision of CRDS was limited to 10-15permeg. Here, we will present a new metholodology that allows to reach a similar or even better precision compared to the mass spectrometric approach. The improved methodology does not require any hardware changes but is solely based on modifications of the injection procedure. 
Bimodal diel pattern in peatland ecosystem respiration rebuts uniform temperature response
Authors: Peichl Matthias , Järveoja Järvi , Crill Patrick M. , Nilsson Mats B.
Published: March 2020

Accurate projections of climate change impacts on the vast carbon stores of northern peatlands require detailed knowledge of ecosystem respiration (ER) and its heterotrophic (Rh) and autotrophic (Ra) components. Currently, however, standard measurement techniques (i.e. eddy covariance and manual chambers) generate semi-continuous empirical ER data (i.e. during only night- or daytime, respectively) that are extrapolated to the daily scale based on the paradigm that assumes a uniform diel response to temperature. Here, using continuous autochamber measurements of hourly ER, Rh and Ra in a boreal peatland, we demonstrate a distinct bimodal pattern in diel ER which contrasts the unimodal pattern inherent to the classical assumption. This feature results from divergent temperature dependencies of day- and nighttime ER due to differing contributions from Rh and Ra. We show that the classical approach overestimated daily ER by up to ~2-fold and growing season ER by 16-23%. These findings call for improved process-based understanding of ER to avoid bias in simulations of peatland carbon cycle-climate feedbacks.
Balancing Local and Global Sustainability of Urban Water Supply Systems with Water Security and Resilience Goals
Authors: Krueger Elisabeth , Borchardt Dietrich , Jawitz James , Rao Suresh
Published: March 2020

The sustainability of urban water systems is commonly analyzed based on local characteristics, such as the protection of urban watersheds or the existence of nature-based solutions for stormwater drainage. Water embedded in food and other goods consumed within cities, or the pollution caused by their production is generally not assessed as part of urban water system sustainability. However, indirect feedbacks can produce negative impacts (e.g., drought and water quality impairments) resulting from these water and ecological footprints. We therefore suggest that, within the context of nexus thinking, embedded water and ecosystem impacts should be part of urban water governance considerations.

We quantify the local and global sustainability of urban water supply systems (UWSS) based on the performance of local sustainable governance and the size of global water and ecological footprints. Building on prior work on UWSS security and resilience, we develop a new framework that integrates security, resilience, and sustainability to investigate trade-offs between these three distinct and inter-related dimensions. Security refers to the level of services, resilience is the system’s ability to respond to and recover from shocks, and sustainability refers to the long-term viability of system services. Security and resilience are both relevant at local scale (city and surroundings), while for sustainability cross-scale and -sectoral feedbacks are important. We apply the new framework to seven cities selected from diverse hydro-climatic and socio-economic settings on four continents. We find that UWSS security, resilience, and local sustainability coevolve, while global sustainability correlates negatively with security. Approaching these interdependent goals requires governance strategies that balance the three dimensions within desirable and viable operating spaces. Cities outside these boundaries risk system failure in the short-term, due to lack of security and resilience, or face long-term consequences of unsustainable governance strategies. Our findings have strong implications for policy-making, strategic management, and for designing systems to operate sustainably at local and global scales, and across sectors.

The corresponding article was accepted for publication in Environmental Research Letters on Jan. 15, 2020.
High resolution paleosecular variations recorded in Lake Pleshcheevo sediments (Yaroslavl region, Russia)
Authors: Nurgaliev Danis , Dilyara Kuzina , Lina Kosareva , Nuriia Nurgalieva , Pavel Krylov , Anatoly Borisov , Damir Khassanov
Published: March 2020

In this paper we present the results of paleomagnetic investigations of the Lake Pleshcheevo sediments (Yaroslavl region, Russia). Sediments of modern lakes are a unique record's archive changes of environment, climate, geomagnetic field over the past millennia. From lake were selected 4 cores up to 6.3 meters. From the core using a special sampler was selected undeformed samples for petromagnetic and paleomagnetic investigations. Magnetic susceptibility, NRM (modulus and direction), demagnetization by an alternating magnetic field were made for all samples. The absolute age of the sediments was determined using the radiocarbon dating. To establish the absolute age of magnetization in sediments, it is necessary to use information from observational, archaeomagnetic, and other data. After correlation of data from Lake Pleshcheevo sediments with archaeomagnetic and other corrected limnomagnetic records, we were able to construct an adequate time scale for recording geomagnetic variations. The obtained changes of direction of the characteristic NRM component of sediments were compared with archaeomagnetic data and records of geomagnetic field variations reconstructed from studies of lake sediments in Western and Eastern Europe. There is observed a very good agreement of all these data. It testifies the high quality of the magnetic record in the sediments of the Pleshcheevo Lake and the need for special studies and obtaining a high-quality master curve of the geomagnetic field variations over the last 12 thousands years for the European part of Russia.

This work was funded by the Russian Science Foundation under grant № 18-17-00251. Authors acknowledge measurements at the resource Center "GEOMODEL", Scientific Park of Saint-Petersburg State University.
Detection and understanding of water quality deviation events in the drinking water supply network of the Poblenou Sector (Barcelona), Spain
Authors: Plà-Castellana Mireia , Roselló-Cano Julia , Maestro Alícia , Raich-Montiu Jordi , Paraira Miquel
Published: March 2020

Monitoring critical drinking water points in the water distribution system of Barcelona (Catalonia, Spain) is an increasing concern. The control of several quality parameters as free chlorine, total organic carbon (TOC), conductivity, turbidity, temperature, colour, pressure and flow are necessary to ensure a supply of safe and clean drinking water to consumers.

The aim of this project is to investigate the consequences of alterations detected in the water distribution system, to find the focus of occurrences and controlling them to provide a better drinking water quality to Barcelona citizens.

Barcelona procures drinking water to its citizens via two main water sources: Ter and Llobregat Rivers. They have intrinsic quality differences and they must be treated in different ways. With the purpose of controlling and investigating how these differences impact the water quality supplies, two s::can sensor systems were installed in the Poblenou District (Barcelona). The first one (nano::station) was installed in a drinking water distribution pipe, and the second one (pipe::scan) was installed in a domestic water supply network. Both systems were situated in the same drinking water confluence sector in order to compare the data recorded and to visualise water quality changes. More than 20 events were recorded, analysed and classified according to whether the alteration was due to an occasional event in the domestic water supply or to an external incident from the water distribution system. Some detected events were related to an increase of temperature, a rise of water demand, the water origins or changes in pressure.

One important event recorded by the installed probes was an increase of temperature, directly associated with an augment of total organic matter (TOC) at the beginning of summer (June 2018). A great rise of TOC would be the causer of high consumption of free chlorine that it could be hazardous for human health if there is not enough chlorine dissolved in water. Due to this temperature increment (from 15°C to 23°C in a few days), the minimum level of chlorine (less than 0.2 mg/L) was registered in the Poblenou Sector.

Nano::station and pipe::scan sensor systems are excellent tools as on-line water quality controllers. These kinds of sensors can record variations occurring every two minutes, giving a great perception of the events that are happening at different points of the drinking water city-wide network.
Variations of electrical characteristics of near-surface atmosphere of the Earth during magnetic storm
Authors: Riabova Svetlana , Spivak Alexander
Published: March 2020

Temporal variations of the electric field in near-surface layer of the Earth are determined by many factors, among which strong disturbances of the magnetic field should be especially noted. Magnetic storms cause an increase in the ionospheric electric field, which leads to variations in the gradient of the electric field potential near the Earth's surface. We consider the effect of magnetic storms in variations in the electrical characteristics of the atmosphere at Geophysical observatory «Mikhnevo» of Sadovsky Institute of Geosphere Dynamics of Russian Academy of Sciences and at Center for geophysical monitoring of Moscow of Sadovsky Institute of Geosphere Dynamics of Russian Academy of Sciences. We used data from the continuous monitoring of three components of the magnetic field, vertical components of the atmospheric electric field and atmospheric current carried out in fair weather. Experimental data processing and analysis show that accompanying magnetic storms with geomagnetic K index more or equal 5 increased variations in the electric field and vertical atmospheric current are characterized by different morphological structures. It is currently difficult to interpret the data. Nevertheless, the research results can be of great help in the development and verification of theoretical and computational models for generating variations in the electric field as a result of strong geomagnetic disturbances.
Assessing the quality of climate information for adaptation.
Authors: Baldissera Pacchetti Marina , Dessai Suraje , Bradley Seamus , Stainforth David A
Published: March 2020

There are now a plethora of data, models and approaches available to produce climate information intended to inform adaptation to a changing climate. There is, however, no analytical framework to assess the epistemic issues concerning the quality of these data, models and approaches. An evaluation of the quality of climate information is a fundamental requirement for its appropriate application in societal decision-making. By integrating insights from the philosophy of science, environmental social science and physical climate science, we construct an analytical framework for “science-based statements about future climate” that allows for an assessment of their quality for adaptation planning. We target statements about local and regional climate with a lead time of one to one hundred years. Our framework clarifies how standard quality descriptors in the literature, such as “robustness”, “adequacy”, “completeness” and “transparency”, rely on both the type of evidence and the relationship between the evidence and the statement. This clarification not only provides a more precise framework for quality, but also allows us to show how certain evidential standards may change as a function of the purpose of a statement. We argue that the most essential metrics to assess quality are: Robustness, Theory, Completeness, Adequacy for purpose, Transparency. Our framework goes further by providing guidelines on when quantitative statements about future climate are warranted and potentially decision-relevant, when these statements would be more valuable taking other forms (e.g. qualitative statements), and when statements about future climate are not warranted at all.
Model Assessment Strategy in a Karst Hydrological Model Using a Process-based Diagnostic Tool
Authors: Ozdemir Calli Kubra , Melsen Lieke , Hartmann Andreas
Published: March 2020

Model assessment is a crucial part of hydrological modelling studies. The traditional intuitive approach is to judge model performance to explore its effectiveness and informativeness about the system reality. However, this approach does not necessarily guarantee that one captures system hydrological functioning from the model output. Here, we proposed a novel model assessment strategy that provides a direction to constrain model output space with the concept of model functionality. In the study, we used StorAge Selection (SAS) function approach as a process diagnostic tool to explore the model output space which is simultaneously informative on the system hydrological behaviour and functioning. To do that, the SAS model was fed by a karst-dedicated hydrological model (VarKarst) simulations to model the karst aquifer d18O transport and young water fraction of system discharge, Fyw. Model functionality was assessed by a new model verification metric, named Exceedance Probability Ranked Score, EPRS. The eligible clusters from the model output were then served in order to examine the model parameter space. Our findings provide direction to indicate that using young water fraction, Fyw as a process-diagnostic metric leads to an improvement in model realism while carrying a physically realistic model parameter set throughout the model output space.
Quantifying similarities between computational expensive reactive transport models
Authors: Mohammadi Farid , Scheurer Stefania , Schäfer Rodrigues Silva Aline , Oladyshkin Sergey , Hommel Johannes , Nowak Wolfgang
Published: March 2020

The microbially induced calcite precipitation (MICP) process is a reactive transport, which consists of various important biogeochemical processes, namely precipitation, and dissolution of calcite, adhesion of the biomass on surfaces, detachment of the biomass from the biofilm as well as growth and decay of the biomass. Due to the accumulation of the biofilm and especially the calcite precipitation, the flow conditions in the subsurface can be modified and especially the porosity and permeability can be reduced, so that the existing leakages are sealed. This sealing property of MICP is of interest in different applications, such as sealing cracks in gas tanks or in a cap rock for CO2 underground storage

The process of biofilm growth in porous media using MICP can be described by many models with different complexity and assumptions. Typically, complex models require more measurement data to constrain their parameters. Therefore, there is a need to seek a balance between model complexity and efforts for acquiring field data. To do so, the modelers are interested in assessing the similarities among these models and their prediction accuracy by comparing them with field observation data.

In this study, we perform a Bayesian model legitimacy analysis to investigate the similarities among different MICP models and their prediction accuracy. Moreover, this analysis provides a model ranking based on computed model weights, achieved within the framework of Bayesian model selection (BMS). This framework requires many model evaluations, which makes the analysis intractable for computationally expensive MICP models. To overcome this issue, we use surrogate models that are constructed using arbitrary polynomial chaos expansion (aPCE). To account for the approximation error, we introduce a correction factor that compensates the inaccuracies due to replacing the original models by the surrogates.