bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigating the impacts of clustering of floods on insurance practices; a spatiotemporal analysis in the USA
Authors: Papoulakos Konstantinos , Iliopoulou Theano , Dimitriadis Panayiotis , Tsaknias Dimosthenis , Koutsoyiannis Demetris
Published: March 2020

Recent research has revealed the significance of Hurst-Kolmogorov dynamics and inherent uncertainties in flood inundation and flood mapping. However, classic risk estimation for flood insurance practices is formulated under the assumption of independence between the frequency and the severity of extreme flood events, which is unlikely to be tenable in real-world hydrometeorological processes exhibiting long range dependence. Furthermore, insurable flood losses are considered as ideally independent and non-catastrophic due to the widely spread perception of limited risk regarding catastrophically large flood losses. As the accurate risk assessment is a fundamental process on flood insurance and reinsurance practices, this study investigates the effects of lack of fulfillment of these assumptions, paving the way for a deeper understanding of the underlying clustering mechanisms of stream flow extremes. For this purpose, we present a spatiotemporal analysis of the daily stream flow series from the US-CAMELS dataset, comprising the impacts of clustering mechanisms on return intervals, duration and severity of the over-threshold events which are treated as proxies for collective risk. Moreover, an exploratory analysis is introduced regarding the stochastic aspects of the correlation between  the properties of the extreme events and the actual claim records of the FEMA National Flood Insurance Program which are recently published.
Effect of different soil carbon amendments on the post-harvest dynamics of soil microbial biomass carbon and -nitrogen in an agricultural field experiment
Authors: Clayton Jessica , Rothardt Steffen , Reichel Rüdiger , Bonkowski Michael
Published: March 2020

Every year agricultural soils lose significant amounts of nitrogen (N) over winter through N leaching and gas emissions as a result of freeze-thaw cycles. The incorporation of carbon amendments after harvest, such as crop residues or other carbon rich material, can help to promote soil microbial growth, and in doing so, immobilise N within the microbial biomass. It is still unclear which amendments are most effective at promoting microbial N immobilisation and at what time they should be incorporated into the soil to give best results.

In order to investigate this, we measured soil microbial biomass carbon (Cmic) and -nitrogen (Nmic) at 12 timepoints between harvest and spring in soils from an established agricultural field experiment in Kiel (Germany). We selected plots which had the same fertilisation regime and crop rotation (Faba bean-winter wheat-winter barley rotation) but differed in soil carbon amendment treatment; removal of residues (control), wheat straw, faba bean, and sawdust.  In addition to microbial biomass measurements, we measured microbial nutrient limitation at each timepoint via substrate induced respiration, in order to give a qualitative indication of microbial activity in respect to growth limiting nutrients.

Our data show that there was little effect of wheat straw in comparison to the control on the microbial biomass carbon or -nitrogen, but different patterns were observed for the latter amendments. Cmic generally decreased over time after harvest in all treatments, but again the decreases were less pronounced in the faba bean and sawdust treatments. Nmic decreased over time after harvest in control and wheat straw treatment but increased with time in the faba bean and sawdust treatments, suggesting improved N immobilisation by the microbial biomass for these treatments. We found that all soils were nearly always N limited throughout the winter and were never P limited. However, a shift to C limitation was observed after addition of fertiliser in spring, except for in the sawdust treatment, which remained N limited despite the addition of mineral N in the field. This result suggests that sawdust has a higher potential for N immobilisation compared to the other soil amendments.

In summary, there was little difference in the microbial post-harvest dynamics between the control and wheat straw treatments but stronger effects were observed in the faba bean and saw dust treatments, which suggested improved microbial N immobilisation. Interestingly, the sawdust amendment seemed to have the highest potential for microbial N immobilisation over winter and enduring into spring.
Monitoring early stages of P release from fertilizer pellets to bulk soil using non-invasive sampling techniques
Authors: Petroselli Chiara , Williams Katherine , Ghosh Arpan , Scotson Callum , McKay Fletcher Daniel , Ruiz Siul , Walker Nancy , Sousa Dias Tiago Gerheim , Roose Tiina
Published: March 2020

Phosphorus (P) is a development-limiting nutrient for crops, hence global food production relies on P fertilizer application. However, P mobility in soil depends on many abiotic and biological processes, most notably its chemical interactions with the soil particles. Optimizing the timing and amount of fertilization could lead to higher production efficiencies and also reduce P runoff and subsequent contamination of water bodies. Plants have developed strategies to improve P uptake by optimizing the root system architecture and exuding organic acids for enhancing P mining locally to the root tips. However, these adaptations are mainly a response to low P availability or to already immobilized P patches in soil, and little is known about the fate of P in the early stages of fertilization.

In this framework, we developed an experimental assay for investigating P release from the fertilizer pellets, and its movement through soil using non-invasive microdialysis sampling techniques and inductively coupled plasma - mass spectrometry (ICP-MS) analytical techniques. Microdialysis allowed for time resolved in-situ samplings and the small size of the probes also allows for a fine spatial resolution.

Results showed a very rapid release of the P from the fertilizer pellet (triple super phosphate, TSP), producing a high concentration pulse that lasts a few hours. P concentrations then decrease over time until reaching steady low concentrations after 6-8 days and P replenishment from the pellet was not observed after the first pulse. The experiments showed that the speed of P movement in soil is greatly influenced by soil particle size distribution, and that gravity plays an important role in promoting quick P movement in the downward direction, while diffusion can account for P observed in the upward direction. Modelling was also applied to data fitting for quantifying trends and deriving an effective P diffusion coefficient in saturated soil.
Transport under advective trapping
Authors: Hidalgo Juan J. , Neuweiler Insa , Dentz Marco
Published: March 2020

Advective trapping occurs when solutes enter a low velocity zone in the porous medium. Current multirate mass transfer (MRMT) models consider slow advection and diffusion but do not separate these processes, which makes parameterization difficult. Here we investigate the impact of advective trapping on transport in media consisting of isolated low permeability inclusions. Breakthrough curves show that effective transport changes from a streamtube model to genuine MRMT as the degree of disorder of the inclusion arrangement increases. We discuss the mathematical formulation in the MRMT and CTRW frameworks and the impact of the spatial geometry on the ergodicity and stationarity of large scale transport. These finding give new insight into transport into transport in highly heterogeneous media.
Tracing the thermohaline Conveyor Belt circulation; from the Drake Passage to the Pacific Ocean
Authors: Berglund Sara , Döös Kristofer , Nycander Jonas
Published: March 2020

This study describes an important pathway of the thermohaline conveyor belt circulation and connects the geographical distribution of water masses with water mass transformation. 
In the Southern Ocean, cold and fresh water up-wells to the surface and returns northward, entering the Pacific, Atlantic and Indian Ocean. This reflects an important part of the thermohaline conveyor belt circulation. As the water flows northward, it changes temperature and salinity, and thus density. These changes can be caused either by internal mixing or air-sea interactions. 

In this study, Lagrangian trajectories are used to follow the pathway from Drake Passage to the warm Pacific Ocean. Trajectories are started in the Drake Passage, and are ended when they either reach 25$^\circ$C or return to the Drake Passage. The trajectories entering the Pacific Ocean follow the Antarctic circumpolar current and separate then into two pathways. The first enters the Pacific Ocean close to the South American coast and flows along the coast until it reaches 25$^\circ$C close to the equator. The second pathway, which corresponds to most of the total volume transport entering the Pacific, are subducted around 40$^\circ$S. The water then moves westward until it reaches Australia where it turns northward and ultimately joins the equatorial undercurrent. 

Along these two pathways, the water changes temperature and salinity, going from cold and fresh to warm and saline. Preliminary results indicate that the water mass transformation for the first pathway are due to air-sea interactions, and internal mixing for the second. 
The long-lived anthropogenic radionuclides I-129 and U-236 as tracers of water mass provenance, circulation timescales and mixing in the Arctic Ocean and Fram Strait
Authors: Wefing Anne-Marie , Casacuberta Núria , Christl Marcus , Smith John N. , Dodd Paul A. , Chamizo Elena , López-Lora Mercedes , Synal Hans-Arno
Published: March 2020

Anthropogenic chemical tracers are powerful tools to study ocean circulation timescales, water mass provenance and mixing regimes. In the Arctic Ocean, the releases of artificial radionuclides from European nuclear reprocessing plants (RPs) act as valuable transient tracers as they label the inflowing Atlantic Waters with a distinct anthropogenic signal. In recent years, the combination of the two long-lived radionuclides 129I and 236U has emerged as a new tracer pair and several studies have shown their potential to track pathways and timescales of Atlantic Water circulation in the Arctic Ocean and Fram Strait.

The circulation times of Atlantic-origin waters in the Arctic Ocean that were inferred using this tracer pair (in combination with the naturally occurring 238U) agree to those obtained by means of other transient tracers. Moreover, the combination of 129I and 236U promises to be a useful marker of water mass mixing regimes both in the surface waters and the subsurface Atlantic layer. In particular, the interface between Atlantic and Pacific Waters in the polar surface layer of the Arctic Ocean can be easily identified as these two water masses are labelled by very different 129I/236U and 236U/238U atom ratios.

Here we present a compilation of 129I and 236U in a quasi-synoptic pan-arctic section including the Fram Strait and we show how this data can be used to gain information about circulation patterns. We discuss timescales and transport characteristics of Atlantic Water flow, the position and variability of the front between Atlantic and Pacific Waters and the temporal variability of Pacific Waters in the Fram Strait.
Improving Visualisation of In-Vivo Root Anatomy and Fluid Transport in Soil Using Iodinated Contrast in Synchrotron XCT and XRF
Authors: Scotson Callum , Williams Katherine , McKay Fletcher Daniel , Koebernick Nicolai , van Veelen Arjen , Roose Tiina
Published: March 2020

Synchrotron X-ray computed tomography (SRXCT) imaging is a technique now commonly deployed for non-destructive 3D visualisation of root morphology in soil environments. However, visualising the internal anatomy of roots in soil using SRXCT can be difficult since the energy required for sufficient X-ray transmission through soil often results in poor contrast between root tissues. This reduces the amount of obtainable information about root anatomy and the effects of the soil environment on plant root internal structure. Contrast media is often used in SRXCT imaging to increase the contrast between tissues, enabling greater ease of both visualisation and image processing for internal structures of biological material.

In this work, we demonstrate that by introducing root material exposed to iodinated contrast media we can overcome these limitations and visualise internal root anatomy of in vivo roots intact within soil. To achieve this, we undertook time-resolved SRXCT imaging of juvenile maize plants growing in a specially designed growth system over a period of 24 hours. This system was designed such that only the base of the primary root would be suspended into iodinated contrast media whilst the rest of the root system remained in soil partially saturated with water, and the plant remained intact and alive. This enabled the basal section of primary root to take up iodinated contrast media without dispersal of the contrast media into the soil. Following the time-resolved imaging of the root system, leaf and stem material were then imaged using SRXCT and mapped using synchrotron X-ray florescence (SRXRF). Using this system, we were able to visualise and segment anatomical root features that are otherwise difficult to capture in vivo in soil using non-destructive 3D imaging such as vascular bundles (including phloem, xylem and proto-xylem) and structures within the cortex. We also gained inferences into fluid flow and transport within in vivo roots in soil based on this technique. The SRXCT imaging as well as the SRXRF mapping of stem and leaf material confirmed transport of the iodinated contrast media through plant vasculature and the distribution into leaf venation. This investigation demonstrates the quantity of data on internal root anatomy and fluid transport for in-vivo roots in soil that could be yielded from SRXCT and SRXRF in future.
Optimizing chambers for stream carbon dioxide evasion estimates; results of a controlled flume experiment.
Authors: Vingiani Filippo , Durighetto Nicola , Botter Gianluca , Klaus Marcus , Schelker Jakob
Published: March 2020

Fluvial ecosystems have a huge potential to affect the global carbon budget. In particular, streams and rivers significantly contribute to carbon dioxide emissions. However, CO2 fluxes from streams to the atmosphere exhibit a marked spatial and temporal variability that is difficult to quantify. Spatio-temporal patterns of biogeochemical fluxes are the result of interconnected unsteady hydrological (e.g. discharge, stream’s length and area, air-water gas exchange velocities) and biochemical conditions. Local estimates of carbon dioxide fluxes from a water body require the simultaneous knowledge of gas exchange coefficients and carbon dioxide concentrations. Different methods (e.g. tracer gas addition, oxygen time series, eddy covariance technique, flux chambers) have been recently developed to obtain point or spatially integrated measures of carbon fluxes under different environmental conditions. Here, we present the results of a flume experiment conducted in the Lunzer Rinnen facility in Lunz am See (Austria). The contribution discusses the dependence of the air-water gas exchange velocities on a set of relevant physical flow properties (i.e. slope, water velocity, discharge). The experimental setup is representative of low slope/velocity streams (flume energy dissipation rate less than 0.01). Gas exchange velocities were evaluated interpreting CO2 observations derived from a standard and an ad-hoc designed flexible-foil CO2 chamber under different deployment modes - anchored and drifting. Our data confirms that higher slopes and flow velocity enhance air-water gas exchange velocities; hence, CO2 outgassing rates in rivers. Moreover, the flexible foil chamber developed for this experiment is shown to be a useful tool for the estimate of local CO2 outgassing rates as it reduces the turbulence induced by the standard chamber on the streamflow. Given the flexibility/simplicity of the floating chamber its use can improve the ability to quantify spatio-temporal patterns of CO2 outgassing in streams.
The representation of Föhn events to the east of the Antarctic Peninsula in simulations by the Antarctic Mesoscale Prediction System (AMPS)
Authors: Kirchgaessner Amélie , King John , Gadian Alan
Published: March 2020

We examine the representation of Föhn events across the Antarctic Peninsula Mountains during 2011 as they were observed in measurements by an Automatic Weather Station, and in simulations with the Weather Research and Forecasting Model (WRF) as run for the Antarctic Mesoscale Prediction System (AMPS). On the Larsen Ice Shelf (LIS) in the lee of this mountain range Föhn winds are thought to provide the atmospheric conditions for significant warming over the ice shelf thus leading to the initial firn densification and subsequently providing the melt water for hydrofracturing. This process has led to the dramatic collapse of huge parts of the LIS in 1995 and 2002 respectively.

We find that, while the model generally simulates meteorological parameters very well, and shows good skills in capturing the occurrence, frequency and duration of Föhn events realistically, it underestimates the temperature increase and the humidity decrease during the Föhn significantly, and may thus underestimate the contribution of Föhn to driving surface melt on the LIS. Our results indicate that the misrepresentation of cloud properties and particularly the absence of mixed phase clouds in AMPS, affects the quality of weather simulation under normal conditions to some extent, and to a larger extent the model’s capability to simulate the strength of Föhn conditions - and thus their contribution to driving surface melt on the LIS - adequately.
Dating crustal anatexis in UHT granulites with Lu-Hf
Authors: Gianola Omar , Cesare Bernardo , Bartoli Omar , Ferri Fabio , Anczkiewicz Robert
Published: March 2020

Ultra-high temperature (UHT) metamorphism is a thermal regime that can be attained by the lower continental crust in exceptional contexts and that is usually accompanied by fluid-absent dehydration melting. Such conditions are observed in the Gruf Complex, a 12 x 10 km migmatitic body located in the Central Alps, which is characterized by the presence of UHT granulitic schlieren and enclaves within migmatitic orthogneisses and charnockites. Two types of granulites, both with a massive and melanocratic texture, were investigated. The first granulite contains sapphirine, garnet, orthopyroxene, K-feldspar and biotite in the peak mineral assemblage, whereas the second type displays garnet, orthopyroxene, sillimanite and biotite. In both granulites, garnets are porphyroblastic and can reach up to 2 cm in size. These garnets are almost pure almandine-pyrope solid solutions and are zoned, showing pyrope-richer rims (Alm43-54Prp43-55Sps0-2Grs1-6) compared to cores (Alm47-62Prp32-48Sps0-3Grs2-9). A clear zoning is also observed in the rare earth elements (REE), with garnet cores showing the highest REE concentrations. Moreover, the porphyroblastic garnets are characterized by the presence of numerous melt inclusions (MI), which can be noticed both in garnet cores and rims. The MI occur as polycrystalline (nanogranitoids) and glassy inclusions, and dominantly display a peraluminous, rhyolitic composition, suggesting that they were originated, along with the host garnet, by incongruent, fluid-absent melting reactions during crustal anatexis. Lu-Hf ages obtained for the MI-bearing garnet cores of both granulites indicate that they formed at about 41 ± 4 Ma, which therefore can be interpreted as the time that crustal anatexis generated the UHT granulites. Considering the granulites in the context of the alpine framework, it is also inferred that UHT conditions in the lower crust were achieved as a consequence of asthenospheric upwelling, probably related to slab steepening or slab breakoff.
Radiocarbon analysis of isoprenoid and branched Glycerol Dialkyl Glycerol Tetraethers in soils and fluvial sediments
Authors: Gies Hannah , Montluçon Daniel , Lupker Maarten , van der Voort Tessa , Hagedorn Frank , Haghipour Negar , Eglinton Timothy
Published: March 2020

Glycerol dialkyl glycerol tetraethers (GDGTs), membrane lipids synthesized by archaea (isoprenoid GDGTs) and bacteria (branched GDGTs), form the basis of a suite of molecular proxies used in terrestrial as well as marine environments. Compound-specific radiocarbon analysis has provided valuable insights into the sources and yielded constraints on transport dynamics of different biomarkers in the context of carbon cycle processes. To complement the existing biomarker radiocarbon toolbox, and to shed new light on the sources and fate of GDGTs, we developed a new method to measure GDGT radiocarbon compositions in natural samples.

Isoprenoid and branched GDGTs are isolated using two UHPLC silica columns in series coupled to a fraction collector set to eluent recovery at different time intervals. The accuracy of the method was tested using a modern and a radiocarbon-dead reference material. Procedural blanks show that the separation procedure adds less than 3 µg carbon with a Fm of 0.64.

The method is first applied to determine the Δ14C composition of isoprenoid and branched GDGTs in two soil core profiles from a temperate and subalpine forest ecosystem in order to explore the range of typical values encountered in natural systems.  The cores, which reach a depth of 80 cm and 40 cm respectively, have previously been analyzed with respect to radiocarbon characteristics of long-chain n-alkanes and fatty acids as well as bulk particulate and dissolved organic carbon (OC) [1]. For each core, GDGTs were separated and analyzed from 3 different depth intervals. The Δ14C of both isoprenoid and branched GDGTs decreases, at a similar rate as the bulk, by -350‰ and -200‰ along the temperate and the subalpine core respectively, hence confirming their potential for constraining transport-dynamics of soil-derived matter in rivers.

The radiocarbon age of GDGTs in a suite of fluvial sediments is older than expected under the assumption that topsoil-derived organic matter is the main source of the compounds. Potentially, this offset could be caused by rapid degradation of the compounds during transport and therefore alter the proxy signal on the way to sedimentary archives.

 

[1] van der Voort, T. S., et al., 2017 - Geophysical Research Letters 44, 23
Links between spring snow cover and long-term alpine vegetation change
Authors: Zong Shengwei , Rixen Christian
Published: March 2020

Snow is an important environmental factor determining distributions of plant species in alpine ecosystems. During the past decades, climate warming has resulted in significant reduction of snow cover extent globally, which led to remarkable alpine vegetation change. Alpine vegetation change is often caused by the combined effects of increasing air temperature and snow cover change, yet the relationship between snow cover and vegetation change is currently not fully understood. To detect changes in both snow cover and alpine vegetation, a relatively fine spatial scales over long temporal spans is necessary. In this study in alpine tundra of the Changbai Mountains, Northeast China, we (1) quantified spatiotemporal changes of spring snow cover area (SCA) during half a century by using multi-source remote sensing datasets; (2) detected long-term vegetation greening and browning trends at pixel level using Landsat archives of 30 m resolution, and (3) analyzed the relationship between spring SCA change and vegetation change. Results showed that spring SCA has decreased significantly during the last 50 years in line with climate warming. Changes in vegetation greening and browning trend were related to distributional range dynamics of a dominant indigenous evergreen shrub Rhododendron aureum, which extended at the leading edge and retracted at the trailing edge. Changes in R. aureum distribution were probably related to spring snow cover changes. Areas with decreasing R. aureum cover were often located in snow patches where probably herbs and grasses encroached from low elevations and adjacent communities. Our study highlights that spring SCA derived from multi-source remote sensing imagery can be used as a proxy to explore relationship between snow cover and vegetation change in alpine ecosystems. Alpine indigenous plant species may migrate upward following the reduction of snow-dominated environments in the context of climate warming and could be threatened by encroaching plants within snow bed habitats.
Global monthly sea surface temperature and sea ice reconstruction for historical simulations
Authors: Samakinwa Eric , Brönnimann Stefan
Published: March 2020

Variability in Sea Surface Temperature (SST) is one of the prime sources of intra-annual variability, and also an important boundary condition for Atmospheric General Circulation Models (AGCMs). In many AGCM simulations, SST and Sea Ice Concentration (SIC) are prescribed. While SSTs are specified according to observations available in recent period of instrumental records (1850 – present), SIC depends on climatological averages with less variability prior to the inception of satellite measurements. This limits our understanding of large-scale climate variations in the past.

In this study, we augment multi-proxy reconstructed annual mean temperature of Neukom et al. (2019) with intra-annual variability from HadISST (v2.0), for 850 years (1000 – 1849). Intra-seasonal variability, such as the phase-locking of El-Nino Southern Oscillation, Indian Ocean Dipole and Tropical Atlantic SST indices to annual-cycle, are utilized. The intra-annual component of HadISST and SST indices estimated from the multi-proxy reconstructed annual mean, are used to develop grid-based multivariate linear regression models using the Frisch-Waugh-Lovell theorem, in a monthly stratified approach. Furthermore, we introduce a scaling technique to ensure homogeneous mean and variance, similar to that of the target. SST observations obtained from ship measurements by ICOADS before 1850, will be integrated in an off-line data assimilation approach.

Similarly, we reconstruct SIC via analogue resampling of HadISST SIC (1941 – 2000), for both hemispheres. We pool our analogues in four seasons, comprising of 3 months each, such that for each month within a season, there are 180 possible analogues. The best analogues are selected based on correlation coefficients between reconstructed SST and its target.
Direct and indirect impacts of climate change on wheat yield in the Indo-Gangetic plain in India
Authors: Daloz Anne Sophie , Rydsaa Johanne , Hodnebrog Øivind , Sillmann Jana , van Oort Bob , Mohr Christian , Agrawal Madhoolika , Emberson Lisa , Stordal Frøde , Zhang Tianyi , Schaller Nathalie
Published: March 2020

The Sustainable Development Goals (SDGs) were adopted by all United Nations members states in 2015. “Erase hunger” and “Establish good health and well-being” are part of these goals and have major implications for agriculture and raises the question of how agriculture will be impacted by climate change. This work focuses on the potential impacts of the changing climate for agriculture, using the example of wheat yield in the Indo-Gangetic Plain (IGP) in India. First, the potential future changes in temperature and precipitation are examined over the IGP in regional climate simulations. The results show an increase in mean temperature and precipitation as well as maximum temperature during the growing season or Rabi season (November-April). Then, the direct (via temperature and precipitation) and indirect (via limiting irrigation) impacts of climate change on wheat yield are derived with a crop model for four selected sites in different states of the IGP (Punjab, Haryana, Uttar Pradesh and Bihar). The chosen sites are spread across the region to represent its major wheat growing areas.

The direct impact of climate change leads to wheat yield losses between -1% and -8% depending on the site examined and the irrigation regime chosen (6, 5, 3 or 1 irrigations). In this experiment, the number of irrigations remain the same in present and future climate. Then, when including the indirect impact of climate change the losses become much higher, reaching -4% to -36% depending on the site examined and by how much the irrigation is limited. This work shows the sensitivity of wheat yield to direct and indirect impacts of climate change in the IGP. It also emphasizes the complexity of climatic risk and the necessity of integrating more indirect impacts of climate change to fully assess how it affects agriculture.
Using 3D printed models to help the understanding of geological maps
Authors: Frizon de Lamotte Dominique , Leturmy Pascale , Souloumiac Pauline , Frizon de Lamotte Adrien
Published: March 2020

Geology is a scientific discipline where a 3D view is important - even essential. When starting to learn geology, as a first exercise students should be able to gain a 3D vision of geological maps, which like all maps are 2D objects, and interpret them. Many people have an objective difficulty in "seeing in 3D", that is, in achieving a mental representation of a dimension, which is not shown. To help them in this task, we propose a wide range of objects, which anyone can use or make in line with an educational approach that combines digital creation and object manipulation. In fact, our computer-designed prototypes are saved in a format from which they can be printed in 3D. Three types of objects are presented:

(1) models, which help to see things in 3D and thus understand particular structures;

(2) models where the third dimension offers an approach to successive geometries (kinematics) during the formation of particular geological structures;

(3) models that provide the opportunity to move different parts relative to each other to generate structures like faults.

We venture that through using our models, and possibly creating other objects by themselves, students will be helped to find their way in this 3D world, which is often confusing at first sight. We will also present printed models of natural examples in different geological context. The target audience is students from first degree to Master's level, trainee teachers, secondary school science teachers and amateur or professional geologists. We also want to reach the growing network of ‘fablabs’, whether or not they are university-based.
Coda-derived moment magnitudes in central Anatolia
Authors: Eken Tuna
Published: March 2020

A reliable representation of the energy at the earthquake source is vitally important to make reliable seismic hazard assessments in tectonically active areas. The use of coda waves, for this aim, can provide source spectra for robust moment magnitude estimates mainly due to its volume-averaging property sampling the entire focal sphere as this makes these waves insensitive to any source radiation pattern effect. In the present study, we examined local earthquakes beneath central Anatolia earthquakes with magnitudes 2.0≤ML≤5.2 recorded at 69 seismic stations that were operated between 2013 and 2015 within the framework of the Continental Dynamics–Central Anatolian Tectonics (CD–CAT) passive seismic experiment. The inversion scheme used here involved simultaneous modeling of source properties as well as seismic attenuation parameters in five different frequency bands between 0.75 and 12 Hz. Forward modeling of coda waves was achieved through an isotropic acoustic Radiative Transfer Theory approach. A comparison between coda derived (Mw coda) and routinely reported local (ML) magnitudes shows an overall consistency. However, apparent move-out observed around small earthquakes (ML < 3.5) can be attributed to wrong assumptions for anelastic attenuation as well as to the use of seismic recordings with a finite sampling interval.
Effects of water stress on photosynthesis，growth and yield in winter wheat
Authors: Zhao Wenhui , Wu Jianjun , Liu Leizhen , Yang Jianhua , Han Xinyi , Tian Feng , Shen Qiu
Published: March 2020

Drought has become one of the major constraints on agricultural development, particularly in areas lacking water. By studying the effects of different water stresses on photosynthesis, growth, yield, water use efficiency (WUE) and other indicators of winter wheat, this study provides scientific irrigation strategies for developing water-saving agriculture. According to the size of the water field capacity, four different water stress levels were set, i.e., 30–40% water field capacity (severe stress), 40–50% (moderate stress), 50–60% (mild stress) and 60–80% (well-watered irrigation), through an automatic irrigation system to create different water stress gradients by controlling the irrigation amount. The results showed that the diurnal and seasonal changes in photosynthetic parameters such as net photosynthetic rate (Pn), intercellular carbon concentration (Ci), stomatal conductance (Gs), and transpiration (E) significantly decreased with water stress intensification. The Pn of mild stress only slightly decreased compared to that of well-watered irrigation and was even higher than after May 16th, resulting in an increase in the dry biomass and 1000-grain weight under mild stress. Under all water stresses, the heights and stem weights of the winter wheat significantly decreased. Moderate and severe stress also significantly reduced the fresh weight of the aboveground biomass, dry weight, spike weight, grain weight, WUE and irrigation water productivity (IWP), while mild stress only slightly decreased the fresh weight of aboveground biomass, spike weight and grain weight. Mild stress increased the WUE and IWP. Thus, mild stress results in the optimal use of water resources without a significant reduction in yield. Therefore, mild stress can be considered as a suitable environment for winter wheat growth in arid areas.
The slip deficit along the North Anatolian Fault (Turkey) in the Marmara Sea: Insights from paleoseismicity, seismicity and geodetic data
Authors: Aksoy Ersen , Meghraoui Mustapha , Toussaint Renaud
Published: March 2020

The North Anatolian Fault experienced large earthquakes with 250 to 400 years recurrence time. In the Marmara Sea region the 1999 (Mw = 7.4) and the 1912 (Mw = 7.4) earthquake ruptures bound the Central Marmara Sea fault segment. Using historical-instrumental catalogue and paleoseismic results (≃ 2000-year database), the mapped fault segments, fault kinematic and GPS data, we compute the paleoseismic-seismic moment rate and geodetic moment rate. The geodetic moment rate is obtained by projecting the measured surface displacements to estimate the strain rate, and evaluating the associated elastic stress rate over a regular spatial grid. The paleoseismic-seismic moment rate is obtained by summing the moment tensors over regions of the spatial grid and periods of time. A clear discrepancy appears between the moment rates and implies a significant delay in the seismic slip along the fault. The rich database allows us to identify the size of the seismic gap and related fault segment and estimate the moment rate deficit. Our modeling suggest that the locked Central Marmara Sea fault segment even including a creeping section bears a moment rate deficit  = 6.4*1017 N.m./yr. that corresponds to Mw ≃ 7.4 for a future earthquake with an average ≃ 3.25 m coseismic slip. Taking into account the uncertainty in the strain accumulation along the 130-km-long Central fault segment, our estimate of the seismic slip deficit being ≃ 10 mm/yr implies the size of the future earthquake ranges between Mw = 7.4 and 7.5.
Deep and intermediate water properties based on Argo floats data in the eastern Nordic Seas
Authors: Merchel Malgorzata , Walczowski Waldemar
Published: March 2020

The Nordic Seas play an important role in global climate change. Compared with other areas, this region has the largest ocean surface and air positive temperature anomalies in the world. It is particularly important for the water masses formation and modification and for interactions between the ocean and atmosphere. This region is also the main route for freshwater and heat exchange between the North Atlantic and the Arctic Ocean.

Because the ship-borne measurements are performed usually during the spring to the autumn season, there is no data to analyze seasonal changes in the intermediate and deep water. The Argo floats, operating throughout the whole year, allow observation of seasonal changes that occur in particular regions. This is especially important in the Nordic Seas, where conditions of the oceanographic observations are very difficult even during the summer.

In this study we analyze hydrographic data collected by the Argo floats in the eastern part of the Nordic Seas region in 2008-2017. Based on the data, both the temporal and spatial variability of the basic physical parameters of the intermediate and deep water were analyzed. It allowed determining how the properties of these waters changed both seasonally and spatially.

The study was funded by the Ministry of Science and Higher Education, Poland under grant agreement No. DIR/WK/2016/12 for the research infrastructure EURO-ARGO ERIC and the National Science Centre, Poland within the DWINS Project (2016/21/N/ST10/02920).
Experimental imaging of focused fluid flow through a viscous porous rock-analogue.
Authors: van Noort Reinier , Yarushina Viktoriya
Published: March 2020

Seismic chimneys have been observed in sediments overlying reservoirs containing different fluids, such as water, hydrocarbons, or CO2. Furthermore, such chimneys have been linked to pockmarks and gas seepages on the seafloor. Visco-plastic models show how these chimneys can form by focused fluid flow through viscous, porous materials. However, the mechanisms that cause fluid flow to focus along such relatively narrow pathways with transiently elevated permeability have not been investigated thoroughly in experiments.

We present analogue experiments carried out in a transparent Hele-Shaw cell, in which a fluid is injected into an aggregate of viscous grains, leading to transient focused fluid flow. Fluid flow is imaged using a digital camera, and our observations are compared to models describing chimney formation.
Seasonally fitted probability functions changing weights for combining vegetation indices forecasting models
Authors: Bounouh Oumayma , Essid Houcine , Farah Imed Riadh
Published: March 2020

Normalized Difference Vegetation Index (NDVI) serves as a significant reference for crop health monitoring. NDVI time series forecasting is a critical issue because of the importance of the involving fields, e.g., food scarcity, climate changes and biodiversity. Therefore, several forecasting models have been suggested and implemented in the literature. Herein, we propose a combination of forecasts using seasonally fitted probability functions changing weights. Contrary to commonly suggested combination models, this one does not rely on overall error measures and/or features, but on time slots similarities between probability density function (PDF) of real observations and forecasts. It is validated with 18 years MOD13Q1 NDVI time series describing a cereal canopy area that belongs to the northwestern of Tunisia. Additionally, the chosen forecasting models are Box Jenkins and Neural Network model. The forecasting accuracy was assessed using the root mean square error (RMSE). According to the results, each season had a different best-fit probability distribution function. Overall, these latter are: Gamma, Beta, Weillbul, and Extreme Generalised Value (EGV). Moreover, the suggested model has shown better forecasting accuracy than individual models, hybrid models and commonly used combining tool (RMSE respectively, 0.003, 0.45, 0.35, 0.38). Interestingly, another seasonally varying weights were determined based on the normal distribution. But, our suggested model showed better forecasting accuracy than this latter (RMSE of normally distributed changing weights= 0.30).

 

 

 

 
Skill improvement of snow-dominated reservoir inflow forecasts using seasonal weather predictions
Authors: Moreydo Vsevolod , Gartsman Boris , Khan Valentina , Tischenko Vladimir
Published: March 2020

We present the post-processing technique for the operational ensemble forecasting system (EFS) currently applied to the Cheboksary reservoir on the Volga River in Russia. The operational forecasting system is built around the ECOMAG semi-distributed hydrological model and has shown to produce reliable forecasts of spring snowmelt water inflow into the reservoir on lead-times up to four months ahead (Gelfan et al., 2018). We propose the improvement of the mean reservoir monthly inflow forecast skill by constructing cumulative distributions (CDF) of the observed streamflow conditioned on the predicted streamflow from the EFS and observed mean monthly air temperature and precipitation. We overcome the limitation of short time-series of the observed variables by multivariate modelling procedure allowing for the time-series extension. The extended time-series are then classified into 64 categories each containing the unique combination of the predictors by their quartile values, and the observed monthly inflow CDFs are constructed. The improved operational forecast CDF is consequently picked from the obtained 64 CDF classes by defining the appropriate CDF class from the combination of the raw ensemble forecast and any weather prediction available. The proposed technique was assessed by using the SL-AV weather model (Khan, 2011; Tolstykh, 2017) monthly temperature and precipitation hindcasts for the evaluation period of 1982 – 2010. The forecasts were benchmarked against climate and observed (perfect) weather forecast and have shown improvement in terms of reliability and resolution.

The research is supported by the Russian Science Foundation, project no. 17-77-30006.

References:

Gelfan, A., Moreydo, V., Motovilov, Y., & Solomatine, D. P. (2018). Long-term ensemble forecast of snowmelt inflow into the Cheboksary Reservoir under two different weather scenarios. Hydrology and Earth System Sciences, 22(4). https://doi.org/10.5194/hess-22-2073-2018

Tolstykh, M., Shashkin, V., Fadeev, R., and Goyman, G.: Vorticity-divergence semi-Lagrangian global atmospheric model SL-AV20: dynamical core, Geosci. Model Dev., 10, 1961–1983, https://doi.org/10.5194/gmd-10-1961-2017, 2017

Khan V.M., Kryzhov V.N., Vilfand R.M., Tishchenko V.A., Bundel A.Y. Multimodel approach to seasonal prediction. Russian Meteorology and Hydrology. 2011. Т. 36. № 1. С. 11-17.
Patterns of urban cloud modifications
Authors: Fuchs Julia , Cermak Jan
Published: March 2020

Clouds in the urban boundary layer interact with the urban land surface via different linkages, resulting in prominent spatial and temporal patterns over or downwind of cities - called here patterns of urban cloud modifications. Depending on meteorological context, an enhancement of fair-weather cumulus clouds or a faster dissipation of fog and low stratus can be encountered. As the role of clouds in the climate system is among the largest remaining uncertainties in climate science, a more complete understanding of cloud systems is required and the dynamic urban setting may serve as a testbed. 

The aim of the study is the spatiotemporal quantification of urban cloud patterns and properties over Europe. Changes of low-cloud properties including cloud occurrence frequency and microphysical properties are spatially and seasonally mapped for the urban centres of Europe using satellite observations (MODIS, SEVIRI). The identification of spatial patterns of urban cloud modifications for specific cloud types and season will provide essential information on location, thermodynamic conditions and intensity of urban centres impacting low clouds. A systematic quantification of the overall spatial and temporal patterns of urban clouds would therefore set a basis for studying drivers of urban cloud modifications and their feedbacks on the urban climate.
Eastern Mediterranean Drying: Projected Changes in Dynamics and Thermodynamics and Their Relation to Large-Scale Processes
Authors: Elbaum Eilat , Garfinkel Chaim , Adam Ori , Morin Efrat
Published: March 2020

Observations from the past century and projections for the end of this century exhibit a decrease in precipitation over the Eastern Mediterranean Sea and surrounding land areas, but the magnitude of the expected drying is unknown. Changes in precipitation are controlled by both thermodynamic (moist) and dynamic (dry) processes, but the relative contributions of these processes, in particular on regional scales, is not well understood. Previous studies have analyzed the ability of the fifth phase of the Coupled Model Intercomparison Project (CMIP5) multi-model mean to represent the spatial and seasonal patterns of the Mediterranean hydroclimate. A wide spread exists among the individual models, which can be exploited to better understand the factors controlling future climate. Garfinkel et al. (2020)[i] found that large-scale mechanisms contribute about 50% of the model spread in Eastern Mediterranean drying. This study further explores the variance across models in projected changes of the moisture budget by decomposing them into mean dynamic, mean thermodynamic and transient components. These components are then related to the variance across models in projected large-scale processes. Through these analyses, uncertainties regarding future changes in precipitation can be reduced.

[i] Garfinkel, C. I. et al. (2020) ‘The role of zonally averaged climate change in contributing to inter-model spread in CMIP5 predicted local precipitation changes’, Journal of Climate, 33, pp. 1141–1154. doi: 10.1175/JCLI-D-19-0232.1.
Predicting water discharge on alpine catchments with downscaled seasonal forecasts
Authors: Callegari Mattia , Cavedon Valentina , Crespi Alice , Greifeneder Felix , Petitta Marcello , Zebisch Marc , Notarnicola Claudia
Published: March 2020

The prediction of seasonal water availability is a key element for an effective water storage management and hydropower production optimization. Here we propose a machine learning model for monthly water discharge prediction, which is based on statistical relationships between time series of a target, i.e. monthly water discharge, and predictors. The considered predictors can be divided into two classes: the initial catchment state variables and the seasonal forecast variables. Snow plays a crucial role as water storage component in alpine catchments. Thus, snow water equivalent is the predictor employed to describe the initial state of the catchment. To ensure the scalability of the method, snow water equivalent is represented here by ERA-5 climate reanalysis data (0.25° x 0.25° resolution). Depending on the prediction season, seasonal forecast of temperature can drive snowmelt or evapotranspiration, while precipitation provides a natural contribution to the total water availability. To describe these prediction variables, we employed a downscaled and bias-correction version of the ECMWF’s seasonal forecasting system (SEAS5) for temperature and precipitation. More specifically, the seasonal forecast fields were bilinearly downscaled from the original 1° x 1° resolution to the target ERA-5 grid and statistically corrected for bias in respect with ERA-5 data by means of a quantile mapping procedure. ERA-5 reanalysis data were used as reference for the bias-correction in order to allow the approach to be easily applied over different areas.

We tested the proposed method over an alpine catchment in Ulten Valley, South Tyrol, Italy, which is managed by three artificial reservoirs for hydropower production. For this catchment, a time series from 1992 to 2017 of measured daily water discharge is available. The water discharge prediction performances of the proposed method are compared with the ones obtained by considering the water discharge monthly climatology.