bluuebunny/crossref_metadata_2025 huggingface dataset:
From Flash Flood Vulnerability and Risk Assessment to Property Damage Prediction: the Value of Machine Learning
Authors: Alipour Atieh , Abbaszadeh Peyman , Ahmadalipour Ali , Moradkhani Hamid
Published: March 2020

Flash floods, as a result of frequent torrential rainfalls caused by tropical storms, thunderstorms,
and hurricanes, are a prevalent natural disaster in the southeast U.S. (SEUS), which frequently
threaten human lives and properties in the region. According to the U.S. National Weather
Service (NWS), flash floods generally initiate within less than six hours of an intense rainfall
onset. Therefore, there is a limited chance for effective and timely decision-making. Due to the
rapid onset of flash floods, they are costly events, such that only during 1996 to 2017 flash
floods imposed 7.5 billion dollars property damage to the SEUS. Therefore, estimating the
potential economic damages as a result of flash floods are crucial for flood risk management and
financial appraisals for decision makers. A multitude of studies have focused on flood damage
modeling, few of which investigated the issue on a large domain. Here, we propose a systematic
framework that considers a variety of factors that explain different risk components (i.e., hazard,
vulnerability, and exposure) and leverages Machine Learning (ML) for flood damage prediction.
Over 14,000 flash flood events during 1996 to 2017 were assessed to analyze their characteristics
including frequency, duration, and intensity. Also, different data sources were utilized to derive
information related to each event. The most influential features are then selected using a multi
criteria variable selection approach. Then, the ML model is implemented for not only binary
classification of damage (i.e., whether a flash flood event caused any damage or not), but also for
developing a model to predict the financial consequences associated with flash flood events. The
results indicate a high accuracy for the classifier, significant correlation and relatively low bias
between the predicted and observed property damages showing the effectiveness of proposed
methodology for flash flood damage modeling applicable to variety of flood prone regions.
Towards real-time monitoring with a seismic antenna at Merapi volcano
Authors: Metaxian Jean-Philippe , Santoso Agus Budi , Beauducel François , Dahamna Nabil , Monteiller Vadim , Fahmi Ali
Published: March 2020

Seismic antennas are often used on volcanoes to analyse emergent signals as LP events or tremor.  In fact, they can be used for any kind of seismicity whether the signal is impulsive or emergent. In this work we are using a seismic antenna as an instrument for monitoring the continuous seismic signal, with the objective of a real-time application.

A seismic antenna composed of 5 broadband stations equipped with Guralp CMG-6TD stations was installed in November 2013 close to the summit of Merapi, on the site called Pasar Bubar. Sensors have a flat response characteristic from 30 s to the Nyquist frequency (50 Hz). This network has an aperture of 280 m. The shortest distance between sensors is 100 m.

 

In the perspective of a real-time application, the main analysis, which consists of estimating the slowness vector, requires a shorter computation time than the data acquisition time. We thus focused on a signal processing technique based on the calculation of time delays on the vertical component only and in a single frequency band. Given a set of time delays and associated errors calculated between each couple of sensors in the frequency domain, the corresponding slowness vectors can be recovered by inversion. Slowness vectors are estimated for successive time-windows in the frequency band 0.5-3 Hz. Temporal series of back-azimuth and apparent slowness are deduced with respect to time.

The analysis strategy for monitoring is then the following: A weight function expressed as a function of the derivatives of the time delays is calculated for successive moving time-windows. This function was designed in order to identify areas of stability of the back-azimuth values as function of time. A PDF of the back-azimuth and apparent slowness is then estimated for time series of 1 hour. This gives information on the dominant activity by time unit.

We will show the results obtained with the analysis of several months of continuous signal which are including different types of events generated by the on-going eruptive activity of Merapi: 1) volcano-tectonic events, 2) Multi-Phase (MP) events related with magma ascent in the conduit, 3) low-frequency events, 4) Rock-falls and 5) Pyroclastic density currents.
Learnt variability as a tool for climate prediction and predictability
Authors: Nadiga Balasubramanya
Published: March 2020

Whether it is turbulence fluid flows or climate variability, there is a big gap between our ability to develop understanding of underlying phenomena/processes and our ability to produce skillful predictions. We focus on near-term prediction of climate as an example. In this context, the state-of-the-art is such that we are able to predict how 30-year global averages of surface temperature will change, but we are unable to predict shorter time scale regional changes.  We investigate a range of deep learning approaches to the problem ranging from reservoir computing to deep convolutional Long Short-Term Memory network architectures. The best performing architectures are seen to be capable of predicting an Earth System Model’s leading modes of global temperature variability with prediction lead times of up to a year. This approach is proposed as a useful practical tool for climate prediction. Further insight into the difficulty of the prediction problem is provided by considering the Lorenz '63 model: Long prediction horizons seen when the system is fully observed is seen to be progressively degraded as the system is less thoroughly observed, while noting the difficulty of fully observing the earth system
Identifying the radiative ‘twilight zone’ surrounding shallow cumulus clouds from high-resolution ASTER observations
Authors: Mieslinger Theresa , Brath Manfred , Buehler Stefan A. , Stevens Bjorn
Published: March 2020

The uncertain radiative effect of shallow cumulus clouds over tropical ocean significantly contributes to the high uncertainty in climate sensitivity estimates. Radiances corresponding to clear-sky and cloudy areas can be observed in moderate resolution satellite images. To observe the radiance originating from very small clouds and from the transition zone surrounding shallow cumulus clouds, the ‘twilight zone’, high-resolution data is required. Twilight zone radiances can be higher than clear-sky radiances due to unresolved cloud fragments and/or humidified aerosols. The area of the twilight zone depends on the resolution of the underlying data. If we think of the twilight zone in terms of partially cloudy pixels, such an area results in a high uncertainty in cloud and aerosol retrievals, as they are based on cloudy and clear-sky assumptions respectively. A precise knowledge of radiances from clouds and their twilight zone is decisive in terms of the total cloud reflectance and subsequently the shallow cumulus cloud radiative effect, which climate models struggle to properly simulate.

We therefore investigate the abundance and importance of such a twilight zone from high-resolution satellite images from ASTER recoded previously and during the EUREC4A field campaign. We use radiative transfer simulations to model the contribution of background clear-sky radiances including aerosols. Subtracting known clear-sky radiances from observed cloud field radiances leaves us with a precise knowledge of non-clear-sky radiances originating from shallow cumulus clouds and their surrounding twilight zone.
Impact of a realistic Greenland ice sheet melting on the North Atlantic over the period 1920-2014
Authors: Swingedouw Didier , Devilliers Marion , Mignot Juliette , Deshayes Julie , Garric Gilles , Ayache Mohamed
Published: March 2020

Greenland experienced intensive melting over the last century, especially in the 1920s and over the last decades. The supplementary input into the ocean is influencing the freshwater budget of the North Atlantic. Simultaneously, some signs of a recent weakening of the Atlantic meridional overturning circulation (AMOC) have been reported. In order to better understand the possible impact of the melting on the North Atlantic circulation, salinity and temperature trends, we construct an observation-based estimate of the freshwater fluxes from 1840 to 2014 associated to the runoff fluxes from Greenland ice sheet and surrounding glaciers and ice caps. Input from iceberg melting is also included and spatially distributed over the North Atlantic following an observed climatology. We force historical simulations of the IPSL-CM6A-LR coupled climate model with this reconstruction from 1920 to 2014. The 10-member ensemble mean displays freshened and cooled waters around Greenland, which spread in the subpolar gyre, and then towards the subtropical gyre and the Nordic Seas. Over the whole period, the convection is reduced in the Labrador and Nordic Seas, while it is slightly enhanced in the Irminger Sea, and the AMOC is reduced by 0.32±0.35 Sv at 26°N. This highlights that the AMOC decrease due to Greenland melting remains modest in these simulations and can only explain a very moderate amount of the 3±1 Sv weakening suggested in a recent study. The multi-decadal trend of the North Atlantic surface temperature obtained with the additional freshwater forcing is more in line with observations than in standard historical simulations. We also show a clear improvement of the representation of the 1995 abrupt warming in the subpolar gyre in the melting ensemble, which may thus be partly forced by Greenland ice sheet melting. Mechanisms at play imply changes in the variability of the AMOC in the melting ensemble as compared to the historical one. Such an impact on forced decadal variability has crucial consequences for decadal prediction systems that may gain skill by including observed Greenland ice sheet melting.
Dynamics of redox potential and nutrient turnover in dry floodplain soils during a simulated rain fall event
Authors: Schlögl Johanna , Cramaro Lena , Griebler Christian , Haderlein Stefan B.
Published: March 2020

Floodplain soils experience highly dynamic wet and dry cycles that trigger changes in redox conditions and as such play a crucial role for environmental nutrient cycling and pollutant fate.

To elucidate the effects of varying water saturation on the predominant biogeochemical processes and their dynamics we simulated a heavy rain fall event with subsequent steady rain over ten consecutive days at a plot of arable soil in a floodplain near Tübingen, southwest Germany. We monitored how soil redox conditions, redox sensitive soil constituents and microbial communities responded to changing water saturation.

 

The experiment design was fully randomized comprising irrigated plots mimicking rain events and dry controls.

Multi-level redox probes recorded in situ redox potentials at 10 cm intervals down to 90 cm depth on irrigated and dry plots. The initially dry soil showed redox potentials of +600 mV. The simulated heavy rain fall provoked a drop in redox potentials within hours in depths down to 40 cm and within a delay of 1 to 2 days in depths down to 60 cm. Subsequent steady rain lead to a decrease of the redox potentials to a minimum of -200 mV to -300 mV in depths of 20 to 30 cm and -100 mV in depths of 40 to 50 cm.

Soil cores were retrieved throughout the experiment to identify microbial communities and to determine depth profiles of nitrate, ammonium, adsorbed and poorly crystalline iron as well as total iron, and sulfide and sulfate in the pore water and the solid phase.

 

The high resolution temporal data on changes in redox potential, soil chemistry and soil microbial communities will be presented and discussed in terms of the predominant biogeochemical processes in the soil profile.
Will climate change impacts the biogeochemical cycles of essential micronutrients?
Authors: Richon Camille , Tagliabue Alessandro
Published: March 2020

Trace metals are important micronutrient for marine microbial life. They support many metabolic reactions necessary for bacteria, phytoplankton and zooplankton, however, some trace metals such as Cu or Zn may have toxic effects at high concentrations. The processes shaping trace metals distribution and cycling in the ocean are still poorly understood. Furthermore, the evolution of trace metals distributions as a consequence of climate change has never been investigated.

This work aims at characterizing the potential impacts of climate change on the global biogeochemical cycling of essential trace metals. We use a state-of-the-art global ocean biogeochemical model representing a suite of trace elements (Fe, Cu, Zn, Co, Mn) to investigate how their distribution and inventories may change in response to the RCP8.5 climate change scenario. The changing ocean circulation in this scenario may result in surface stratification, resulting in changes in biological pump strength, oxygen distribution and particle loadings. In regions affected by external inputs, surface concentration of micronutrient may increase as a result of surface stratification. On the other hand, surface micronutrient concentrations may decrease in the open ocean as a result of the decline in vertical supply of nutrients. We use an extended Redfield ratio calculation in order to characterise the changes in trace metal concentrations and highlight the regions where trace metal cycling is the most affected by climate change. Results show that cobalt and manganese concentrations display important evolutions in the Arctic whereas zinc is mostly impacted in the Southern Ocean. Our results suggest that changes to the ocean physics and productivity will impact trace metals differently depending on their role and biogeochemical drivers.

 

 
Monitoring natural CO2 flow in the mofettes of the West Bohemia seismoactive region
Authors: Vlček Josef , Fischer Tomáš , Lanzendörfer Martin
Published: March 2020

Monitoring of CO2 degassing in seismoactive areas allows the study of correlations of gas
release and seismic activity. Reliable continuous monitoring of the gas flow rate in rough field
conditions requires robust methods capable of measuring gas flow at different types of gas
outlets such as wet mofettes, mineral springs and boreholes. In this paper we focus on the
methods and results of the long-term monitoring of CO2 degassing in the West
Bohemia/Vogtland region in Central Europe, which is typified by the occurrence of
earthquake swarms and emanations of carbon dioxide of magmatic origin. Besides direct
flow measurement using flowmeters, we introduce a novel indirect technique based on
quantifying the gas bubble contents in a water column, which is capable of functioning in
severe environmental conditions. The method calculates the mean bubble fraction in a water-
gas mixture from the pressure difference along a fixed depth interval in a water column.
Laboratory tests indicate the nonlinear dependence of the bubble fraction on the flow rate,
which is confirmed by empirical models found in the chemical and nuclear engineering
literature. Application of the method in a pilot borehole shows a high correlation between the
bubble fraction and measured gas flow rate. This was specifically the case of two coseismic
anomalies in 2008 and 2014, when the flow rate rose during a seismic swarm to a multitude
of the pre-seismic level for several months and was followed by a long-term flow rate decline.
However, three more seismic swarms occurring in the same fault zone were not associated
with any significant CO2 flow anomaly. We surmise that this could be related to the slightly
farther distance of the hypocenters of these swarms than the two ones which caused the
coseismic CO2 flow rise. Further long-term CO2-flow monitoring is required to verify the
mutual influence of CO2 degassing and seismic activity in the area.
Impact of re-scaled macro models for GNSS orbit determination
Authors: Villiger Arturo , Dach Rolf , Jäggi Adrian
Published: March 2020

Radiation pressure from the sun and the Earth are not negligible forces for orbit determination. Most analysis centers use empirical approaches (i.e., the classical Empirical CODE Orbit Model ECOM or the adapted version ECOM2), analytical approaches (simplified box wing models or detailed macro models), or a combination of both to account for the solar radiation pressure (SRP) and Earth radiation (albedo).

The European GNSS Agency and the Cabinet Office, Government of Japan, disclosed meta data for Galileo resp. QZSS satellites. For the other GNSS constellations either no or incomplete models are available. This is in particular problematic for SRP modeling. In case of albedo the issue is less critical as the corresponding force acting on GNSS satellites is much smaller compared to the SRP. Our approach to overcome this issue is to re-scale the existing box-wing models based on long term analysis (one year) and introduce the re-scaled macro models for the final orbit determination. The main goal is to achieve better orbit quality with fewer empirical parameters compared to our traditional solution based on pure empirical SRP models.  The key factors to determine the quality of the re-scaled macro models are, among others, the evaluation of the resulting orbits and the behavior of the long term time series of the corresponding geodynamic parameters.
ESMValTool - introducing a powerful model evaluation tool
Authors: Predoi Valeriu , Andela Bouwe , De Mora Lee , Lauer Axel
Published: March 2020

The Earth System Model eValuation Tool (ESMValTool) is a powerful community-driven diagnostics and performance metrics tool. It is used for the evaluation of Earth System Models (ESMs) and allows for routine comparisons of either multiple model versions or observational datasets. ESMValTool's design is highly modular and flexible so that additional analyses can easily be added; in fact, this is essential to encourage the community-based approach to its scientific development. A set of standardized recipes for each scientific topic reproduces specific diagnostics or performance metrics that have demonstrated their importance in ESM evaluation in the peer-reviewed literature. Scientific themes include selected Essential Climate Variables, a range of known systematic biases common to ESMs such as coupled tropical climate variability, monsoons, Southern Ocean processes, continental dry biases and soil hydrology-climate interactions, as well as atmospheric CO3 budgets, tropospheric and stratospheric ozone, and tropospheric aerosols. We will outline the main functional characteristics of ESMValTool Version 2; we will also introduce the reader to the current set of diagnostics and the methods they can use to contribute to its development.
Quantitatively assessment and application of climate change risk
Authors: Wu Shaohong
Published: March 2020

Risk assessment of climate change is a base for adaptation. Quantitative methods are the key step for the risk assessment. This study tries to establish a quantitative methodology for assessment of risks from climate change through elements of the dangerousness of risk causing factors, the exposure and vulnerability of risk bearing bodies, and their interrelations. In this study, risks were divided into abrupt hazard risk and gradual hazard risk. Quantified risk calculating models were established with the damage degrees from regression of historical hazard losses, vulnerability curve construction. Then risk assessment was done on three main extreme events, heat-wave, drought and flood. According to the current status and needs, this study projects the future risks of climate change under different climate scenario. The method was applied in China and West Africa.
Seismicity cluster below the Moho indicates thrust faulting in the central Ligurian Basin
Authors: Thorwart Martin , Dannowski Anke , Kopp Heidrun , Lange Dietrich , Crawford Wayne , Paul Anne , Wolf Felix Noah
Published: March 2020

The Alpine orogen and the Apennines system are part of the complex tectonic settings in the Mediterranean Sea caused by the convergence between Africa and Eurasia. Between 30 Ma and 15 Ma, the Calabrian Subduction retreated in southeast direction pulling Corsica and Sardinia away from the Eurasian continent. In this extensional setting, the Ligurian Sea was formed as a back-arc basin. The rifting jumped 15 MA ago to the Tyrrhenian Sea leaving Corsica and Sardinia in a stable position relative to Eurasia as observed by GPS measurements.

Within the framework of the AlpArray research initiative and its German component “4D Mountain building” (SPP2017 4D-MB) a long-term experiment was conducted in the Ligurian sea to investigate the lithosphere structure and the seismicity in the Ligurian basin. The passive seismic network was operated by France and Germany and consisted of 29 broad-band ocean bottom stations. It was in operation between June 2017 and February 2018. At the end of the experiment two active seismic profiles were conducted additionally.

A cluster of 15 events with magnitudes lower than 2.5 occurred in the centre of the Ligurian Basin. The earthquakes are located at a depth of 20 km to 35 km, i.e. 10 - 25 km below the Moho. The cluster was not continuously active but had several active periods which lasted between 2 and 5 days.

A fault plane solution could be determined of the larger events in the cluster. The mechanism is a thrust faulting. Smaller events should have a similar mechanism due to the highly coherent waveforms. A similar mechanism was observed for the Mw=4.9 earthquake on 07.07.2011 which occurred 50 km east of the cluster. Both solutions show a SW-NE striking, northwest dipping fault plane. This indicates a convergence in NW-SE direction between Corsica and Eurasia.
Investigating the sensitivity in production of SOA from its precursor VOCs with different sources of emissions using an interactive chemistry climate model
Authors: Vats Pawan , Ganguly Dilip , Biswas Anushree
Published: March 2020

The organic aerosols (OA) contribute significantly to fine particulate mass in the atmosphere, however, most global climate models do not include elaborate treatment associated with the production of secondary organic aerosols (SOA) involving complex chemical processes to save computational time. As a result, the concentrations of SOA simulated by these climate models are often highly uncertain. Moreover, very limited research has been done on SOA and its precursors, particularly on the contribution of individual sources towards the SOA concentrations across India. In this study, we investigate the sensitivity of the production of SOA from different VOC sources and different atmospheric oxidants by the Community Atmospheric Model version 4 coupled with an extensive interactive atmospheric chemistry module (CAM4-Chem). The main objective of our present research is to understand the contribution of individual sources of VOCs towards the production and distribution of SOA across the Indian region. We carried out a series of systematically designed simulations using the CAM4-Chem model to understand the sensitivity of simulated SOA over the Indian region to changes in only emissions of VOCs from anthropogenic, biogenic, and biomass burning emissions from preindustrial (PI) to present-day (PD) period. In order to avoid the influence of changes in meteorology from PI to PD on the production of SOA, all simulations are performed for the same period from 2004 to 2014 with identical meteorology prescribed to the model based on MERRA2 data, while the VOC emissions from anthropogenic, biogenic, and biomass burning sources are allowed to change from PI to PD in different simulations. Our results show that the simulated distribution of SOA over the Indian region in PD is linked to the significant changes in the emissions of VOCs from anthropogenic, biogenic, and biomass burning emissions sources from PI to PD. We find that the changes in emissions of VOCs from biogenic sources from PI to PD associated with land use and land cover changes contribute significantly along with the changes in emissions from anthropogenic sources towards the total changes in SOA distribution over the Indian region over the same period.  The global annual mean burden of SOA from our sensitivity simulations vary in the range of 0.65Tg to 0.80Tg due to variations in emission of different VOCs that are precursors to the production of SOA in the atmosphere. These sensitivity simulations improve our understanding of atmospheric chemistry and specifically about the formation of SOA from different precursor gases originating from diverse anthropogenic, biogenic, and biomass burning emissions sources. More results with greater detail will be presented.
Effect of different agricultural management practices on soil quality in maize intensive production.
Authors: Luísa Ana , oliveira carlos , Campos Isabel , Pelayo Oscar , Serpa Dalila , Kaizer Jacob , Gomes Ana Paula , Abrantes Nelson
Published: March 2020

Potential changes in soil quality as result of intensive agriculture are increasingly raising concerns about associated impacts and the need to implement more sustainable agricultural practices. Among several intensive crops, maize, an important human food source, is one of the most intensely produced around the world, representing harmful consequences for soil quality. Therefore, it is fundamental to understand how different agricultural management practices can influence soil quality. Hence, the main objective of this study was to compare the implications of the conventional tillage versus non-tillage in soil quality. Additionally, it was also an objective to evaluate how the implementation of herbage strips, non-irrigated and fallow areas, contribute to soil sustainability and biodiversity preservation, compensating the impacts of intensive maize cultivation. For this purpose, an integrative approach was adopted including physical-chemical parameters (e.g. bulk density, pH, electrical conductivity, field capacity, organic matter, nutrients) and biological parameters (e.g. phosphatase activity, urease activity, ecotoxicological tests with soil organisms).

The obtained results revealed the existence of differences between the analyzed practices, mainly associated with chemical parameters and nutrients. When comparing no-till and conventional sowing, higher mean values for no-till were observed for the following parameters: organic matter, cation exchange capacity, nitrogen, phosphorus, nitrates, calcium, copper, zinc, iron, manganese, urease activity and invertase activity. Hence, this study highlights the importance of the implementation of nonconventional agricultural practices, as is the case of no-till, as promoters of productivity and soil sustainability. Additionally, different management practices as herbage strip, non-irrigated and fallow areas around conventional areas play an additional role in soil quality and biodiversity preservation.
eastern and western med Messinian salinity crisis : comparison scenarii and propositions
Authors: Gorini Christian , Pellen Romain , Rubino jean-loup , Didier Benoit , Montader Lucien , do Couto Damien
Published: March 2020

The partial sequestration of the Mediterranean Sea from adjacent oceans at the end of the Miocene caused an evaporation surfeit that increased the water salinity above the seafloor of the deep basins and peripheral basins. As a result, an up to 2-3 km-thick sequence of evaporites was deposited in the center of the deep basins. This coincided with the concomitantly intense subaerial erosion of the adjacent margins and important Mass transport deposit events all around the peri- Mediterranean slopes. The volume of evaporites deposited in the deep basins implies a periodic connection with the world oceans concomitant with a huge evaporation during all the MSC. “Deep basins” refers to their position in the deep central parts of the extant Messinian basins in the western basin, the central basins (Ionian) and the eastern basins. The configuration of these basins and the distribution and thickness of the evaporites were very different 6 Myr ago due to the Africa Europe convergence. Evaporites deposition at the edge of the evaporites basins was affected by the geodynamic nature of the margins: Tertiary or Mesozoic passive or transform margins (North Africa), strike slip margins (northern and eastern Levant), convergent margins in the North of the East Mediterranean with evaporites subducted or stacked in a fore arc position. We propose a kinematic reconstruction of the central Mediterranean sea to discuss the connections between the Atlantic waters and the eastern Mediterranean Sea. In this presentation, we show that: (1) There is no opposition between the deposition of the first deep water evaporites and a sea level fall of more than 1000 m. (2) by a threshold effect the eastern Mediterranean could have been more restricted than the western Mediterranean during the phase 1 of the MSC, which could explain the two major incisions observed in the Nile delta (3). At the end of the MSC, this threshold effect could have been maximal with an accommodation space almost filled up and a bathymetry probably not exceeding 50 m in the western Mediterranean and in the Central Mediterranean with deposition of K and Mg evaporates, and almost zero in the Eastern Mediterranean as shown by the fluvial network developed on a wide-spread erosional surface on top of the Levant basin salt. (4) The Messinian salinity crisis (MSC) ended with the rapid re-flooding of the Mediterranean sea. A two-step flooding in the western Mediterranean could find its origin in this threshold effect.
Dynamic time warping analysis of the evolution of SMOS surface and in-situ soil moisture time series
Authors: Herbert Christoph , Pablos Miriam , Vall-llossera Mercedes , Camps Adriano
Published: March 2020

A comprehensive understanding of temporal variability of root-zone and surface soil moisture (SM) and the relationship with the underlying soil characteristics is of great importance in hydrological and agricultural applications. For the last ten years, global and frequent satellite SM observations have been available to investigate SM dynamics. However, validating remote sensing retrievals against in-situ observations based on the comparison of collocated SM time series is complicated. While satellite retrievals are approximated from inversion models over an area, in-situ measurements are determined at point-scale. This usually produces different SM dynamic ranges and biases in the corresponding time series. Moreover, the influence of soil properties and meteorological conditions can cause SM time series obtained from indirect remote sensing techniques and direct in-situ observations to be non-linearly related. Dynamic Time Warping (DTW) is a dynamic programming technique, capable of coping with temporal distortions by aiming for finding the optimal match between time series.

 

In this study, DTW was used to provide a time lag evolution as a continuous dissimilarity measure comprising the main temporal variability features of two time series. The DTW technique was applied to SM time series from the Soil Moisture and Ocean Salinity mission (SMOS) L4 product developed at Barcelona Expert Center (BEC) with in-situ measurements at top- and subsoil-representative depth levels, located in the Soil Moisture Measurements Station Network of the University of Salamanca (REMEDHUS) in Western Spain. DTW parameters were customized to the particular input time series to obtain a robust and meaningful time lag. Seasonal differences in SM dynamics were analyzed in a clustering approach by investigating the link between SM time series and SM-regime-related parameters including precipitation and categorical features such as soil type and land use. Since the technique resolves the non-linear behaviour of time series, it has the potential to generally assess major differences in SM acquisition techniques. It could also be useful to investigate spatial SM variability in heterogeneous regions and to make informed choices in future sensor deployment in SM networks.
The impacts of global water stress and the costs of mitigation in the future
Authors: Liu Xingcai
Published: March 2020

Water stress has increased in many regions of the world during the past decades. It would be likely to continue in the near future due to intensified human activities and changing climate. Better projection of future water stress will facilitate water resources management and planning. Based on the improved water stress index (), we assess the future changes in water stress at the country level under climatic change and socioeconomic dynamics (e.g., population growth, economic development, land-use change) across scenarios. The water deficit, the unmet water demands against local water resources, is estimated for each country. The spatiotemporal characteristics of the global water stress are demonstrated and the main driving force is identified for the exacerbated stress on humans. The monetary value of the water deficit is estimated based on the water price valued for different sources of water withdrawal (e.g., surface water, groundwater, desalination, etc.). The total costs to mitigate or eliminate future water stress are estimated for each country. Finally, the risks and vulnerability due to global change in the future are assessed for each country. This study could be a reference for adaptation to climate change and the potential costs to achieve the SDGs in 2030.
Tectonic evolution of shallow water carbonates: the Lastoni di Formin platform (Dolomites - Italy)
Authors: Inama Riccardo , Menegoni Niccolò , Perotti Cesare
Published: March 2020

Carbonate rocks are among the most important targets for hydrocarbon exploration, and are considered of particular interest also for gas storage and carbon dioxide sequestration. The development of complex fracture networks in carbonates have a significant influence in fluid circulation, enhancing porosity and permeability and, therefore, modifying their storage capacity. The middle-Triassic Lastoni di Formin platform (Italian Dolomites) was studied by combining field measurements and photogrammetric techniques. The reconstruction of the Digital Model of the buildup allowed the analysis at the outcrop scale with a resolution of 5-10 cm, and gave the opportunity to focus on the behavior of sub-seismic (<10 m) structural elements. Even though their influence on the reservoir quality has been documented, heterogeneities of this order of dimensions are considered as part of the matrix properties in reservoir modeling: outcrop analogues represents a very good source of data that can help to fill this resolution gap. Many generations of fractures and faults can be distinguished at seismic and sub-seismic scale in the present-day fracture pattern of Lastoni di Formin, that is the result of different successive deformational events. In particular, the outcrop records the presence of two different tectonic phases: an E-W extension (Jurassic), that generate N-S trending joints and normal faults, and the Alpine compression (Neogene), that forms conjugate strike slip faults and flower structures. Moreover, an early fracturing gravitational event can be observed: is represented by opening-mode fractures and extensional faults sub-orthogonal to the direction of progradation of the buildup. The presence of platform-derived materials (oncoids) in the fracture fills allows to time-constrain the genesis of these fractures shortly after the deposition. Bed-perpendicular diffuse fractures, which are often strata-bound or terminate on bed-parallel stilolythes, were also detected. Both the margin-parallel early fractures and the Jurassic structures underwent strike-slip reactivations during the Alpine orogeny, which indicates a N-S to NNW-SSE shortening. Evidence of these movements can be inferred from riedel structures, en-chelon arrays, splays and fault jogs that can be observed at different scale. Reactivation of early structures can indicate that they influenced the distribution of subsequent faults and fractures affecting the platform.

 
Bio-optimisation of a tidal channel
Authors: O'Hara Murray Rory , Lewis Matthew
Published: March 2020

Scotland has ambitious decarbonisation and climate change objectives, such as generating 100% of gross annual electricity consumption from renewable sources by 2020. Tidal stream energy is a renewable and predictable source of energy that converts the kinetic energy within tidal currents, into electricity, using a hydrokinetic device such as a horizontal axis turbine. However, economically viable tidal stream development is currently confined to areas of exceptionally high current speeds, and this can severely limit the choice of area. If the speed threshold required for an economically viable tidal site can be lowered then the number of potential sites could increase dramatically.

It is well known that macro-algae (e.g. kelp) grow in perspective tidal energy sites, as they requiring similar water depths and current speeds. Furthermore, kelp is known to grow in dense patches, reaching from the sea-floor to the ocean surface, and can modify tidal current speeds. Indeed, observations have shown that “kelp forests” can locally reduce current speeds by a third (Jackson and Winant, 1983). This local reduction in current speed will cause an increase in speed elsewhere, in order to conserve mass. Therefore, we hypothesise that by adding a kelp forest in the vicinity of a tidal channel, the current speed and tidal stream resource could be increased sufficiently for the site to become economical.

A three dimensional finite volume hydrodynamic model has been used to model an idealised tidal channel. The drag imposed by kelp was theoretically calculated and represented in the model as a sub grid scale momentum sink. The changes to the current speed resulting from this bio-optimisation of the tidal channel were investigated and show that the current speed in the centre of the channel can be increased. Kelp were then added to a previously developed hydrodynamic model of the Pentland Firth and Orkney Waters to investigate how such bio-optimisation could influence an area currently being considered for substantial tidal stream development. The changes on both the areas of suitable tidal stream development and the power yield are investigated.

Acknowledgements

Matthew Lewis wishes to thank Aaron Owen and Ade Fewings at SuperComputingWales, and Fearghal O'Donncha at IBM-research Ireland for fruitful discussions, and the METRIC grant, EP/R034664/1.

References

Jackson, G. A. and Winant, C. D. (1983). Effect of a kelp forest on coastal currents. Continental Shelf Research, 2(1), pp.75-80.
Attribution of uncertainties in predictions of monsoon precipitation using an energy framework
Authors: Ferreira David , D'Agostino Roberta
Published: March 2020

Recent studies on monsoon dynamics have emphasized that monsoon changes are due to local anomalous Net Energy Input (NEI) in the atmospheric column, rather than being associated with land-sea temperature contrasts as in the classical large-scale sea-breeze view of monsoons. In the energy framework, a positive NEI (convergence of energy) must be balanced by a lateral export of moist static energy, which, if achieved by an overturning cell, is associated with moisture import and net precipitation.

This suggests a strong link between monsoonal precipitations and NEI, providing a pathway to understand uncertainties in predictions of past and future monsoon precipitation.

To investigate this, we exploit the CMIP5 and PMIP3 archives (9 models), comparing simulations of Mid-Holocene (~6000 years ago) and future (end of 21st century, RCP8.5 scenario) climates to pre-industrial (PI) control climate.

Precipitation responses to past and future forcing in monsoon regions exhibit a wide spread which is, as expected, significantly (and positively) correlated with NEI changes. Yet, the latter explain at best 40% of the spread in the precipitation response. In fact, the correlation between NEI and precipitation changes hides a more complex picture.

We show that changes in atmospheric stratification and differences in the control climate contribute to the uncertainties, with varying degrees depending on regions and climates: while the southern hemisphere monsoons are linked to changes in both stratification and NEI, the northern hemisphere monsoons are more strongly associated with stratification changes. Meanwhile, changes in the mid-Holocene are more dominated by NEI changes than in the future climate when stratification changes are larger.
Fault hydromechanical characterization and CO2-saturated water injection at the CS-D experiment (Mont Terri Rock Laboratory)
Authors: Wenning Quinn C. , Rinaldi Antonio P. , Zappone Alba , Grab Melchior , Roques Clement , Webber Ulrich W. , Jaggi Madalina , Bernasconi Stefano M. , Guglielmi Yves , Brennwald Matthias , Kipfer Rolf , Madonna Claudio , Obermann Anne , Nussbaum Christophe , Wiemer Stefan
Published: March 2020

Understanding potential caprock failure through fault zone leakage is crucial for the safe, long-term containment of a CO2 storage site. Thus, the presence of faults in caprocks will greatly affect the site characterization process in terms of the safety assessment. The CS-D experiment at the Mont Terri Lab aims at investigating caprock integrity by determining CO2-rich water mobility in a fault zone. Seven boreholes were drilled in the clay rock, all crosscutting a fault at depths of 17-30 m below the niche floor. The boreholes were fully cored, and the samples analysed in various laboratories. All boreholes were instrumented for monitoring geochemical and geomechanical changes induced by fluid injection for prolonged time, with the goal to better understand mechanisms of CO2 leakage in a faulted caprock. We deployed a multi component monitoring setup measuring pressure, axial and 3D deformation, seismic activity and cross-hole electrical resistivity. A borehole was fully dedicated to the monitoring of the injection front, as well as geochemical in-situ measurements and fluid sampling. A portable mass spectrometer for direct measurements of gas has been installed in a dedicated borehole interval. Injection and monitoring activities started in December 2018, with multiple injection tests with saline water at pressures up to 6 MPa, in order to characterize the hydraulic response of the fault. A prolonged injection of CO2-saturated water at constant head pressure started in June 2019 and lasted for about 8 months. In this contribution, we will present the analysis of the data collected during the fault characterization (hydraulic, geophysics, and core analysis) as well as results of the continuous months-long injection. Preliminary interpretation of the monitoring data suggests that a fault does not necessarily form a pathway for the fluid to escape at shallow depth.
Comparing the boundaries of interplanetary coronal mass ejections
Authors: Cid Consuelo , Larrodera Carlos , Saiz Elena
Published: March 2020

The boundaries of interplanetary coronal mass ejections (ICMEs) are commonly established based on the magnetic field smoothness and/or the low temperature, when compared to normal solar wind. Based on the analysis of the ICME on 2015 January 6-7, observed by Wind and ACE spacecraft, Cid et al. (2016) proposed compositional signatures as the most precise diagnostic tool for the boundaries of ICMEs. Having as a starting point the ICMEs catalogues from Jian et al. (2006) and Richardson and Cane (2010), and the Wind spacecraft ICME catalogue on the NASA web site, we have compared the boundaries of all ICMEs observed by the ACE spacecraft attending to different signatures. This contribution shows the results of the study.
The features of Antarctic Bottom Water in the fracture zones at 7-10 deg. N of the Mid-Atlantic ridge
Authors: Volkova Valentina , Demidov Alexander , Gippius Fedor
Published: March 2020

Despite the fact that there are numerous estimates of the Antarctic Bottom Water (AABW) formation and transport, its evolution and distribution pathways are still debatable (Morozov E.G. et al., 2010).

The main task of this work was to identify the structure and transport of deep and bottom water mass of the fracture zones (7 40', Vernadsky and Doldrums). The research is based on new data (multibeam bottom relief, temperature, salinity, velocity) obtained during the research cruise on the RV "Akademik Nikolaj Strakhov" in October-November 2019 and WODB18 historical data.

The main result of the research is proper estimation of the AABW and LNADW transport, which takes into consideration the influence of fracture zone morphometry. Accordingly, the preliminary circulation scheme of water masses is obtained.
Current and Future Challenges in Modern Port Development and Cultural Heritage Preservation within port infrastructures.
Authors: Alexandrakis George , Petrakis Stelios , Liritzakis Stavros , Kampanis Nikolaos
Published: March 2020

Climate change impact is functioning as risk-multiplier to problems which are already apparent and affect infrastructures. In cases of infrastructures within cultural heritage sites, the problem is more complicated. Sea Level Rise and increased storm events can damage structures not designed to withstand prolonged structural pressure, erosion and immersion. Risks affecting coastal cultural heritage may stem from exposure to several hazards and it is important to facilitate a holistic understanding of the factors driving them. Wave energy and overtopping of coastal structures act as potential hazards for people, property and infrastructure. When, particularly, monuments or landmarks are present within the infrastructures, mitigation measures and monitoring are essential. Depending on the level of acceptable risk and the required degree of certainty related to wave overtopping, coastal engineers rely on predictions derived from semi-empirical desktop methods and numerical models for answers. Moreover, the anticipated increase in extreme events due to climatic change makes protection and prevention actions even more necessary. Additionally, restrictions in fund availability and landscape preservation for coastal monuments, make the designing of such interventions more demanding. In this work, the combination of risk assessment analysis related to increasing sea level and storm frequency, wave numerical modelling, breakwater design and economic sustainability is presented. As case studies, the Venetian Coastal port/Fortress of the city of Heraklion (1523 A.D.) and Venetian port of Rethimnon (13th century A.D.), both located at the North coast of the island of Crete, Greece, are considered. Both ports are tourism hotspots within the region. Numerical modelling results were generally calculated to be consistent with overtopping wave measurements. For the analysis of the wind regime in the near and far future, climatic modelling has been used indicating that, for the coastal area of central Crete, the wind regime is expected to change in the near and far future; an increase not only in wind speeds but also in the prevailing wind directions, the latest affecting the monuments the most. Based on results from on-site measurements and numerical modelling and forecasting, mitigation actions have been proposed, including an expansion of the submerged armouring of the ports infrastructures and the use of natural based solutions for low slope areas, in order to reduce wave energy, run-up and overtopping, so that the monuments can remain functional, safe and accessible for longer periods of time.