bluuebunny/crossref_metadata_2025 huggingface dataset:
The Convergence of IoT, Machine Learning, and Big Data for Advancing Flood Analytics Knowledge  
Authors: Samadi Vidya , Pally Rakshit
Published: March 2021

Floods are among the most destructive natural hazard that affect millions of people across the world leading to severe loss of life and damage to property, critical infrastructure, and agriculture. Internet of Things (IoTs), machine learning (ML), and Big Data are exceptionally valuable tools for collecting the catastrophic readiness and countless actionable data. The aim of this presentation is to introduce Flood Analytics Information System (FAIS) as a data gathering and analytics system.  FAIS application is smartly designed to integrate crowd intelligence, ML, and natural language processing of tweets to provide warning with the aim to improve flood situational awareness and risk assessment. FAIS has been Beta tested during major hurricane events in US where successive storms made extensive damage and disruption. The prototype successfully identifies a dynamic set of at-risk locations/communities using the USGS river gauge height readings and geotagged tweets intersected with watershed boundary. The list of prioritized locations can be updated, as the river monitoring system and condition change over time (typically every 15 minutes).  The prototype also performs flood frequency analysis (FFA) using various probability distributions with the associated uncertainty estimation to assist engineers in designing safe structures. This presentation will discuss about the FAIS functionalities and real-time implementation of the prototype across south and southeast USA. This research is funded by the US National Science Foundation (NSF).
Management of groundwater salinization under a climate change scenario in an aridarea
Authors: Dhaoui Oussama , Horta Ribeiro Antunes Isabel Margarida , Agoubi Belgacem , Kharroubi Adel
Published: March 2021

Most future scenarios for water resources are predicting water scarcity, with a decrease in the amount
of precipitation and limitation on groundwater recharge for the next five decades. In arid and semi-
arid areas, the water quality is a great problem and groundwater salinization is one of the principal
causes of degradation of water resources worldwide.
Menzel Habib aquifer is located in the northwest of Gabès region (southeastern Tunisia), included in
the arid Mediterranean bioclimatic area, with dry hot summers and relatively warm winters.
Groundwater geochemistry from the study area shows a Na-Cl and Ca-Mg-Cl-SO 4 dominant facies.
The high groundwater mineralization and its correlation between total dissolved solids and major ions
suggest a contribution of SO 4 , Cl, Na, Ca and Mg in groundwater salinization processes.
The salinization of groundwater is mainly associated with the Triassic evaporites, with the dissolution
of halite, anhydrite and gypsum, occurring in the area, and related to the tectonic context of the
region. Additionally, other geochemical processes occurred, such is the cation exchange mechanisms.
Changes in precipitation patterns and intensity, with water scarcity, low recharge and excessive
pumping have affected groundwater quantity and quality. Nowadays, the occurrence of climate
changes scenarios is a major drawback for water use for irrigation and drinking water supply in arid
and semi-arid regions, such as Menzel Habib aquifer.
Lateral variations of pressure-temperature evolution in non-cylindrical orogens and 3-D subduction dynamics: the Betic-Rif Cordillera example
Authors: Bessière Eloïse , Jolivet Laurent , Augier Romain , Scaillet Stéphane , Précigout Jacques , Azañon José Miguel , Crespo-Blanc Ana , Masini Emmanuel , Do Couto Damien
Published: March 2021

Orogens closely linked to 3-D subduction dynamics are frequently non-cylindrical and the Mediterranean region is a perfect natural laboratory to observe several of them, as well as their interactions. Through the succession of extension, subduction and sometimes collision events, the kinematic reconstructions of such orogens can be difficult and the subject of active debates. The internal zones are often non-consensual, especially when their long-term Pressure-Temperature-time-deformation (P-T-t-d) evolutions are studied. This complexity is mostly due to pre-orogenic inheritance or complex interactions between the subducting lithosphere, the overriding plate and the asthenosphere. All these elements are described and documented in Mediterranean orogens, i.e., a complex shape of the Eurasian and African margins in pre-orogenic times and a complex slab retreat and tearing dynamics. Their 3-D geometry results in strongly arcuate belts, such as the Betic-Rif Cordillera, located in the westernmost part of the Mediterranean region.

Focused on the Internal Zones of the Betic-Rif Cordillera and based on recent findings (Orogen Project framework), a synthesis of the tectono-metamorphic evolution shows the relations in space and time between tectonic and P-T evolutions. The reinterpretation of the contact between peridotite massifs and Mesozoic sediments as an extensional detachment leads to a discussion of the geodynamic setting and timing of mantle exhumation. Based on new 40Ar/39Ar ages in the Alpujárride Complex (metamorphic formations of the Betic Internal Zones) and a discussion of published ages in the Nevado-Filabride Complex (metamorphic formations of the Betic Internal Zones), we conclude that the age of the HP-LT metamorphism is Eocene in all the Internal Zones. A first-order observation is the contrast between the well-preserved Eocene HP-LT blueschists-facies rocks of the Eastern Alpujárride-Sebtide Complex and the younger HT-LP conditions reaching partial melting recorded in the Western Alpujárride. We propose a model where the large longitudinal variations in the P-T evolution are mainly due to (i) differences in the timing of subduction and exhumation, (ii) the nature of the subducting lithosphere and (iii) a major change in subduction dynamics at ~20 Ma associated with a slab-tearing event.
Pruning residues incorporation and reduced tillage improve soil organic matter stabilization and structure of salt-affected soils in Citrus tree orchard under semi-arid climate conditions 
Authors: Garcia-Franco Noelia , Wiesmeier Martin , Colocho Hurtarte Luis Carlos , Fella Franziska , Martínez-Mena María , Almagro María , García Martínez Eloisa , Kögel-Knabner Ingrid
Published: March 2021

Arid and semiarid regions represent about 47% of the total land area of the world and around 40% of the world’s food is produced there. In these areas, soil salinization is an emerging problem due to unsustainable land management practices and climate change. However, the use of sustainable land management practices in salt-affected soils can offset the negative effects of salinization and increase soil carbon stocks. In a Citrus tree orchard under semi-arid climate conditions, we evaluated the effect of (i) intensive tillage along with flood irrigation (IT); (ii) combination of no-tillage with pruning residues (branches and leaves) as mulch, and drip-irrigation (NT+PM); and (iii) combination of reduced tillage with the incorporation of pruning residues and drip-irrigation (RT+PI), on aggregate stability, amount and quality of organic matter fractions and soil organic carbon (OC) sequestration. Our results showed that the incorporation of pruning residues through reduced tillage decreased bulk density and salinity while soil porosity, soil OC and N stocks, and percentage of OC-rich macroaggregates increased compared to the IT system.  However, the positive effects of the NT+PM system on soil properties were limited to the topsoil. The IT management system showed the highest values of bulk density and salinity and lower amounts of macroaggregates and soil OC stocks. In conclusion, the combination of pruning residues through the reduced tillage and drip-irrigation was the most effective systems to improve soil structure and OC sequestration and reduced the salt content under Citrus tree orchard in semi-arid soils
Erosion effect in the movement process of rapid loess landslide using an improved two-layer model
Authors: Shen Yueqiang , Li Tonglu , Li Dongyang , Nian Tingkai
Published: March 2021

Erosion effect plays a significant role in the run-out process of a rapid loess landslide. This effect is manifested in bed entrainment and frontal plowing on terraced material during movement, leading to the volume amplification. Therefore, an improved two-layer model is proposed to describe the frontal plowing and bed entrainment in this paper. In addition, the bed entrainment rate is further calculated by introducing the bed entrainment physical model. The sliding mass and plowed material are assumed to be immiscible in this model, and the mechanical behaviour between the materials is simulated by considering the interaction force between the two layers. Furthermore, the governing equations are deduced from the mass and momentum conservation. It is then applied to analyze a typical rapid loess landslide, Dongfeng landslide. The results indicate that the bed entrainment and frontal plowing have a significant impact on the mobility of the landslide, which is mainly shown in the following two aspects: 1) the bed entrainment effect significantly increases the speed and volume of the landslide; 2) The frontal plowing effect will impede the motion of the frontal sliding mass, and there is a clear separation between the sliding mass and the plowed material, which is more consistent with the field observations. The improved two-layer model proposed in this paper can provide more reliable assessment to describe the rapid loess landslides with erosion.
Particle tracking model results suggest little lateral transport bias in inorganic and organic SST proxies in the Mediterranean Sea
Authors: Rice Addison , Nooteboom Peter , van Sebille Erik , Peterse Francien , Ziegler Martin , Sluijs Appy
Published: March 2021

Ocean currents can transport sinking particles hundreds of kilometers from their origin at the ocean surface to their burial location, resulting in an offset between sea surface temperatures (SSTs) above the burial site and the particle’s origin. Quantifying this offset in particles carrying molecules used in SST proxies can reduce uncertainty in paleoclimate reconstructions. In the Mediterranean Sea, where δ18Oforaminifera, UK’37- and TEX86-based SSTs can exhibit large offsets from surface conditions, understanding the possible contribution of lateral transport to proxy bias can provide additional insight when interpreting paleoclimate records.

In this study, Lagrangian particle tracking experiments are performed using the NEMO flow field to simulate transport and allow for a quantitative estimate of transport bias. The model determines the ocean surface origin locations of foraminifera and sedimentary particles that carry alkenones or GDGTs to compare with surface sediment datasets for δ18Oforaminifera, UK’37 and TEX86, respectively. A range of sinking speeds appropriate for the export of organic matter (6, 12, 25, 50, 100, 250, and 500 m/d) is used in the model to represent different export modes (i.e., individual coccoliths, coccospheres, aggregates), where the three fastest sinking speeds can also represent sinking foraminifera. Results show that lateral transport bias is generally small within the Mediterranean Sea and cannot explain the large offsets in proxy-based SST reconstructions in this basin.
Responses of gravel-bed rivers to periodic climate change
Authors: McNab Fergus , Schildgen Taylor , Turowski Jens , Wickert Andrew
Published: March 2021

Periodic variation in Earth's orbit leads to variation in temperature and precipitation at its surface that are expected to exert a profound influence on landscape evolution. Indeed, cyclical fluctuations in sediment yield and grain size are a ubiquitous feature of the geological record, and recurrence times of geomorphological features such as fluvial terraces and alluvial fans often appear to reflect orbital periodicities. However, making quantitative interpretations of these records requires a detailed understanding of the ways in which sediment is transported from mountainous source regions along alluvial channels to depositional sinks. Sediment transport processes may dampen (i.e. buffer, 'shred') or amplify climate signals, such as changes in channel elevation or sediment flux, and may introduce a lag between them and the responsible external forcing. Recent modelling studies, mostly focused on the potential transmission of climatic signals to sedimentary archives, have predicted a wide range of behaviour and have proven challenging to test in the field. Here, we aim to clarify this discussion and also consider the potential preservation of climatic signals by fluvial terraces along alluvial channels. Our starting point is a recently developed model describing the long-profile evolution of gravel-bed rivers. This model is the first of its kind to be derived from first principles using physical relationships that have been extensively tested in laboratory settings, and takes a non-linear diffusive form. We employ perturbation theory to obtain approximate analytical solutions to the relevant equations that describe how channel elevation and sediment flux vary in response to periodic fluctuations in discharge and sediment supply. Our solutions contain expressions for response amplitudes and lag times as functions of downstream distance, system 'diffusivity' and forcing frequency. Lag times can be a significant fraction of the forcing period, implying that care is required when interpreting the timings of terrace formation in terms of changes in discharge or sediment supply. We also show that at the onset of periodic forcing, or a change in the dominant forcing period, alluvial channels undergo a transient response as they adjust to a new quasi-steady state. Importantly, this result implies that suites of fluvial terraces can be preserved without the need for significant local base-level fall. Since the expressions presented here are defined in terms of fundamental properties of alluvial channels, they should be readily applicable to real settings.
Combination of remote sensing and meteorological data for estimation of crop water requirements in the irrigated perimeter of Tadla in Morocco
Authors: El Hachimi Jaouad , El Harti Abderrazak , Jellouli Amine
Published: March 2021

In arid and semi-arid regions, agriculture is an important element of the national economy, but this sector is a large consumer of water. In a context of high pressure on water resources (climate change, population growth, desertification, etc.), an appropriate management is required. The development of remote sensing tools: temporal, spatial and spectral resolution offers a better opportunity for hydro-agricultural management. The main objective of this study is to combine climate data with that of optical remote sensing in order to estimate crop water requirements in the irrigated perimeter of Tadla. In semi-arid regions, such as Tadla Plain, a large quantity of water is lost by evapotranspiration (ET). The objective of this study is to use a scientific approach based on the modulation of evaporative demand for the estimation of crop water requirements. This approach is based on the FAO-56 method using image data from the Sentinel-2A and Landsat-8 satellites, and climate data: surface temperature, air humidity, wind speed, global solar radiation and precipitation. It also allowed the spatialization of crop water requirements on a large area of irrigated crops during the 2016–2017 agricultural season. Maps of water requirements have been developed. They show the variability over time of crop development and their estimated water requirements. The results obtained constitute an important indicator of how water should be distributed over the area in order to improve irrigation efficiency and protection of water resources.
Calibration and Validation of Infrared Sounders with Moon and Mercury
Authors: Burgdorf Martin , Buehler Stefan A. , John Viju , Müller Thomas , Prange Marc
Published: March 2021

Serendipitous observations of airless bodies of the inner solar system provide a unique means to the calibration of instruments on meteorological research satellites, because the physical properties of their surfaces change very little, even on large time scales. We investigated how certain instrumental effects can be characterised with observations of the Moon and Mercury. For this we identified and analysed intrusions of the Moon in the deep space views of HIRS/2, /3, and /4 (High-resolution Infrared Sounder) on various satellites in polar orbits and as well some images obtained with SEVIRI (Spinning Enhanced Visible Infra-Red Imager) on MSG-3 and -4 (Meteosat Second Generation), which had Mercury standing close to the Earth in the rectangular field of view.

A full-disk, infrared Moon model was developed that describes how the lunar flux density depends on phase angle and wavelength. It is particularly helpful for inter-calibration, checks of the photometric consistency of the sounding channels, and the calculation of an upper limit on the non-linearity of the shortwave channels of HIRS. In addition, we used the Moon to determine the co-registration of the different spectral channels.

Studies of the channel alignment are also presented for SEVIRI, an infrared sounder with an angular resolution about a hundred times better than HIRS. As we wanted to check the image quality of this instrument with a quasi-point source as well, we replaced here the Moon with Mercury. We found the typical smearing of the point spread function in the scan direction and occasionally a nearby ghost image, which is three to four times fainter than the main image of the planet. Both effects cause additional uncertainties of the photometric calibration.  
Discriminating glacial and volcanic seismicity at Llaima and Villarrica volcanoes, Chile
Authors: Lamb Oliver , Lees Jonathan , Franco Marin Luis , Lazo Jonathan , Rivera Andres , Shore Michael , Lee Stephen
Published: March 2021

The monitoring of seismic activity at active glacier-hosting volcanoes is challenging as volcanic and glacial earthquakes (i.e. icequakes) can have overlapping characteristics (i.e. frequencies, waveform shape and magnitude). Here we present results from the first study to target glacial activity at active ice-covered volcanoes in the Southern Chile. The primary focus so far has been on Llaima volcano, one of the largest and most active volcanoes in the region while hosting >14 km2 of glacial ice on the flanks. We use a combination of automatic multi-station event detection and waveform cross-correlation to find candidate repeating icequakes in seismic data from the permanent volcano monitoring network recorded in early 2019. We identified dozens of low magnitude families of repeating seismic events across two months, the largest of which included over 200 events. These findings are comparable to results from analysis of seismic data recorded at Llaima volcano during the same time period in 2015. The persistent, repetitive nature of these events combined with their waveform characteristics and source locations suggest they originated from multiple sub-glacial stick-slip sources around the upper flanks of the volcano. We also deployed a network of seismo-acoustic sensors at Villarrica volcano in early 2020 to record glacial activity in concurrence with the lava lake and strombolian activity at the summit. We conclude that icequakes at Llaima volcano may be more common than previously thought and has implications for how seismic data at ice-covered volcanoes may be used for assessing future volcanic and glacial hazard potential.
The influence of floating spheres on evaporation suppression under different climatic conditions
Authors: M. Shalaby Maram , N. Nassar Ibrahim , M. Abdallah Ahmed
Published: March 2021

Global warming and population growth increase the need for better management of freshwater resources, in particular in arid and semi-arid regions. Due to increased rainfall variability,  reservoirs became a vital management tool that stores the water during rainfall, thus decrease flood risks and supply water during drought periods. However, large amounts of water are lost by evaporation, which markedly affects reservoirs’ function of ensuring water availability. In Egypt, about 20.0% of the country's Nile share (12.1 to 15.4 billion m3) are lost annually by evaporation from Lake Nasser. The floating covers, i.e. spheres, shade the water surface and act as a physical barrier that decreases energy flux into the water, thus decrease evaporation. Studies that compare the evaporation suppression efficiency of the floating covers, over different climatic conditions, while considering its impact on the water ecology are limited.

A field experiment in an outdoor setting (class A-pan) was conducted for nine months (March to November) in two locations that vary in their climatic conditions, i.e. Aswan and Damanhur, representing northern and southern Egypt, respectively. The water surface was covered by white, black, or multicolor spheres, in addition to the control. Daily evaporation rate (ER), water temperature (WT), evaporation suppression efficiency (ESE), were determined. Moreover, the microalgae growth was measured as an indicator of water ecology.  

Obtained results revealed massive evaporation losses from the uncovered water surface (control) in Aswan location, in which the nine-month average was 2.25 times higher than in Damanhour location. The floating spheres reduced ER in both locations, in particular the white spheres. The ESE in Aswan was less than in Damanhour location. The ESE in Damanhour was 63.38, 58.13, and 54.8%, while in Aswan was 48., 42.5, and 41.6% for white, multicolor and black spheres, respectively. Floating spheres decreased WT in the morning and mid-day, while in the evening the control treatment was the coldest, indicating partial isolation of covered water surface. Irrespective of the spheres’ color, the spheres had no detrimental effect on microalgae growth, indicating enough light penetration and gas exchange through the gaps between spheres.

In conclusion, the floating spheres is an effective mean for evaporation suppression and its efficiency is dependent on the climate and spheres’ color. The ESE of spheres is lower in environments with lower relative humidity. The white spheres are recommended for evaporation suppression without negative impacts on microalgae growth which could be a viable indicator for the ecology of the water ecosystem. Further studies on larger water reservoirs are needed while considering several aquatic organisms.
Integrating NGS GRAV-D gravity observations into high-resolution global models
Authors: Zingerle Philipp , Li Xiaopeng , Willberg Martin , Pail Roland , Roman Dan
Published: March 2021

Within this contribution we present a method that allows a smooth integration of in-situ ground gravity observations into high-resolution global models up to d/o 5400 (2’ global resolution). The functionality is shown on the example of the airborne GRAV-D gravity dataset which is integrated into a global satellite-topographic spherical harmonic model.

Conceptually, the method is divided into three steps: firstly, since the processing is based on residuals, a precursor model needs to be identified which is used for reducing the observations. In the actual example a combination between a satellite-only model (GOCO06s) and topographic model (EARTH2014) is chosen (named SATOP2) to ensure independency to the observations. Secondly, the previously reduced (GRAV-D) observations are gridded onto a regular geographic grid making use of the recently developed partition-enhanced least squares collocation approach (PE-LSC). PE-LSC allows an efficient collocation of virtually arbitrary large datasets using a partitioning technique that is optimized for computational performance and for minimizing fringe effects. As a third and last step, the obtained regular grid gets analyzed and combined with a satellite-only model (GOCO06s) on the normal equation level up to d/o 5400. This can be achieved efficiently by using a so-called kite-normal equation system which emerges when combining dense and block-diagonal normal equation systems (assuming equal accuracies for the ground gravity grid).

The herby obtained global gravity field model, named SGDT, is dominated by the satellite information in the lower frequencies (up to d/o 200), by GRAV-D in the mid-frequencies (d/o 200-2000) and by the topographic information in the high frequencies (above d/o 2000). The main purpose of the SGDT model is to validate the method itself and to allow a comparison of GRAV-D observations to pre-existing ground-gravity data by synthesizing SGDT to actual observation sites.
Climate Data Records of GOMOS/AerGOM stratospheric aerosol extinction coefficient for the Copernicus Climate Change Service: last developments and validation
Authors: Bingen Christine , Robert Charles , Vanhellemont Filip , Mateshvili Nina
Published: March 2021

Stratospheric aerosol extinction coefficient data derived from GOMOS using the AerGOM algorithm are one of the aerosol products provided to the Copernicus Climate Change Services (C3S).

The stellar occultation instrument GOMOS, which sounded the atmosphere in the UV-visible-near IR range on board ENVISAT during the period 2002-2012 was a pioneering instrument, relying on a large number of stars with varying magnitude and temperature making the data inversion challenging. An algorithm called AerGOM was developed as an alternative to the operational algorithm to optimize the retrieval of aerosol properties, and this dataset has been continuously improved since then.

A main milestone of this evolution was the elaboration of Level 3 gridded datasets in the framework of the ESA Aerosol_CCI project. This dataset provides aerosol radiative properties with as main quantity the aerosol extinction coefficient between 350 and 750 nm with a better resolution (bins with 5° latitude and 60° longitude intervals, 5-day time periods) than the usual monthly zonal mean. It is therefore better suited to describe the signature of events such as medium-size volcanic eruptions.

Afterward, an extended exploration of the AerGOM performance in the retrieval of trace gases such as ozone, nitrogen dioxide and nitrogen trioxide led to an adaptation of the retrieval scheme in order to improve the retrieved gaseous species.

The outcome of this exploration performed in the framework of the ESA Living Planet project EXPANSION is now exploited to improve again the Level 2 aerosol extinction coefficient, and the resultant Climate Data Record (CDR) delivered to C3S.

We present here the latest developments in the aerosol extinction coefficient retrieval from GOMOS using AerGOM, and show how we use the improvement of the inversion of gas species to derived the new version of the GOMOS extinction product in Level 2, and the C3S CDR. The validation of the AerGOM dataset with respect to datasets from several contemporary missions such as SAGE II, SAGE III, and OSIRIS is also presented.
Effect of conservation agriculture practices on the resilience of Mediterranean soils to the predicted seasonal drought events
Authors: Morales Laura , Domínguez María T , Herrador Mª Belén , Madejón Engracia , Fernández-Boy Elena
Published: March 2021

How climate change will affect soil functioning is a major concern, especially in Mediterranean agrosystems, where, according to climate change projections, the occurrence of extreme temperatures and drought events will be increased. The main objective of our experiment was to evaluate the effect of land management (tillage system) on soil resilience against a simulated dry-rewetting cycle. Soil samples were collected from an in-situ field experiment established in 2008 in the Guadalquivir Valley, where conservation agriculture practices have been tested. Three different land management practices under a typical Mediterranean wheat-legume rotation system were compared: 1) traditional tillage (TT), 2) minimum tillage (MT) and 3) no-tillage (NT). Following our hypothesis, conservation agriculture practices (reduced tillage and no-tillage) may allow a more mature soil microbial community by reducing soil perturbation, and this would result in higher resistance of soil functioning against drought periods. Soil enzyme activities (β-glucosidase, phosphatase, acetylglucosaminidase, aminopeptidase, and dehydrogenase activities), microbial functional diversity (Microresp method), and soil DNA concentration (as an index of microbial biomass) were analyzed in a base-line sampling. Afterwards, a dry-rewetting cycle was simulated under controlled conditions. 8 subsamples of 50g from each soil sample were hydrated to reach 70% of each soil water holding capacity (WHC) and kept in those conditions for a pre-incubation period of 15 days. After this period, half of the replicates were let dry for 12 days (drought), while the others were maintained at 70% WFC (controls). Finally, all replicates were rehydrated again to the initial water content during a 14 days rewetting period. During this cycle, soil respiration rates were periodically measured to study the evolution of soil microbial activity. Our results showed that initial respiration rates were slightly higher in MT compared to NT (p<0.1), likely due to higher organic C and N content in the MT soils. Drought extremely reduced respiration rates in the three treatments, but the results did not show a clear pattern among treatments. During the rewetting period, respiration rates were significantly higher in drought samples in comparison with the controls, while no significant differences were found for the land management treatments. Besides, land management practices did not have a significant effect on soil DNA concentration, functional diversity of the microbial community, or enzyme activities. To conclude, the absence of a clear effect of land management practices on soil resilience to drought may be due to the experimental conditions. An in-situ experiment will allow us to determine if tillage reduction enhances soil resilience to moisture stress.
Elastic Block Model in the North Andean Sliver
Authors: Jarrin Paul , Nocquet Jean-Mathieu , Rolandone Frederique , Mora-Paez Hector , Mothes Patricia
Published: March 2021

The North Andean Sliver (hereinafter NAS) lies at the northwestern end of the South American plate (hereinafter SOAM). This extensive area exhibits a complex deformation process controlled by the interactions of Nazca, Caribbean, South America plates, and Panama block, producing crustal seismicity, arc-continental collision, and subduction processes. Previous models based on partial GPS data sets have estimated the NAS kinematics as a single rigid block moving towards northeast  at 8-10 mm/yr (Nocquet et al. 2014, Mora-Paez et al 2019). By contrary, geologic interpretations as well as seismotectonic data propose more complex kinematic models based on the interaction of several blocks (Audemard et al 2014, Alvarado et al 2016).  Here, we present an updated and most extensive interseismic horizontal velocity field derived from continuous and episodic GPS data between 1994 and 2019 that encompasses the whole North Andean Sliver.  We then interpret it, developing a kinematic elastic block model in order to simultaneously estimate rigid block rotations, consistent slip rates at faults and the spatial distribution of interseismic coupling at the Nazca/NAS megathrust interface. Our model is not constrained either by a priori information derived from geologic slip rates or by a priori information of creeping faults. In contrast with previous simplest models, our model will allow us to estimate the degree of slip partitioning more precisely along the NAZCA/SOAM convergence as well as an improved model of interseismic coupling. We will discuss our coupling distribution with respect to previous models, and our block geometry quantifying the goodness of fit, resolution,  and considering its consistency with geological interpretations.
Can high rates of passive volcanic gas emissions induce reservoir depressurization at Ambrym volcano (Vanuatu)?
Authors: Shreve Tara , Grandin Raphaël , Boichu Marie
Published: March 2021

Satellite-based UV spectrometers can constrain sulphur dioxide (SO2) fluxes at passively degassing volcanoes over decadal time scales. From 2005 to 2015, more than 15 volcanoes had mean passive SO2 fluxes greater than 1 kiloton per day. Although the processes responsible for such high emission rates are not clearly established, this study aims to investigate the impact of strong degassing on the pressurization state of volcanic systems and the resulting ground deformation. One possible result of high degassing rates is the depressurization of the region where the melt releasing gas is stored, which may result in subsidence at the Earth’s surface. Passive degassing may depressurize pathways between deep and shallow magma storage regions, resulting in magma ascent and possibly eruption.

A lumped-parameter model developed by Girona et al., 2014 couples the mass loss by passive degassing with reservoir depressurization in an open volcanic system. However, this model has yet to be tested using real measurements of gas emissions and ground deformation. In our study, we focus on Ambrym volcano, the past decade’s top passive emitter of volcanic SO2, which exhibits intriguing long-term subsidence patterns and no obvious pressurization preceding eruptive periods. We compare subsidence rates measured by InSAR to the system’s average daily SO2 flux, focusing on a subsidence episode spanning 2015 to 2017 that is not clearly linked to magma removal from the system. Using realistic input parameters for Ambrym’s system constrained by petrology and gas geochemistry, a range of reservoir volumes and conduit radii are explored. Large reservoir volumes (greater than 30 km3) and large conduit radii (greater than 300 m) are consistent with depressurization rates obtained from geodetic modelling of InSAR measurements using the Boundary Element method. By comparing these values of reservoir volume and conduit radius with those estimated from geodesy, gas geochemistry, and seismology, we test the applicability and discuss uncertainties of the aforementioned lumped-parameter physical model to interpret the long-term subsidence at Ambrym volcano as a result of sustained passive degassing.
Development of a dynamic European residential building stock typology for energy system analysis
Authors: Kleinebrahm Max , Naber Elias , Weinand Jann , McKenna Russell , Ardone Armin
Published: March 2021

In recent years, different approaches have been developed with the aim of defining representative buildings that can be used as a basis for residential building energy system analyses. Due to the coupling of different sectors at the household level, the analysis of future residential energy systems is becoming increasingly complex. On the European level a large amount of data has been published over the last years. This study combines multiple different data sets relevant for energy system analysis at the building level and presents a dynamic methodology for the derivation of representative building/household combinations, which can be used as a basis for residential energy system analyses on a European level. The approach enables representative buildings to be generated dynamically taking into account the parameters relevant to the respective research question. In a first step, various data sets are combined to describe local building properties, weather conditions, economic and ecological framework conditions as well as socio-demographic parameters on NUTS3 level. Based on the developed database, a two-step procedure for the derivation of building household combinations is presented. In the first step, a synthetic European population is generated by using iterative proportional fitting. In the second step different cluster approaches are compared for the derivation of case specific archetype buildings. Finally, the developed methodology is used in an exemplary way for the analysis of the potential of energy self-sufficient single-family buildings in the future European building stock by using a mixed integer linear programming optimization model for the optimal energy system design and dispatch of residential buildings, taking into account relevant framework conditions such as weather conditions, regulatory framework conditions and site-specific building properties.
Characterizing groundwater recharge dynamics and response times in large sedimentary basins using 14C age tracer data and a reactive transport modeling approach
Authors: Fernandez Nicole , Pryet Alexandre , Saltel Marc , Atteia Olivier
Published: March 2021

Large sedimentary basins represent major groundwater resources vital in sustaining terrestrial ecosystems and the various socio-economic activities essential to modern day society (drinking water supply, health, agriculture, energy, and industry). To address the ongoing and future impacts of climate change and anthropogenic activities on groundwater sustainability a better understanding of groundwater storage and flow dynamics in these multi-aquifer systems is crucial. Groundwater ages in this respect serve as an effective tool, providing valuable insight into rates and sources of groundwater recharge and subsurface heterogeneity. In this study we investigated the well-studied Aquitaine Basin located in Southwest France, the 2nd largest sedimentary basin in the country, with an extensive repository of hydrologic and geochemical data spanning several decades. A 3D regional numerical flow model was developed and extended to simulate reactive transport of radiogenic, 14C. An inverse modeling approach using available 14C activity data is implemented to infer groundwater ages and constrain modern and historic recharge sources and aquifer response times. Preliminary findings from spatial variations in 14C concentrations and groundwater ages point to the role of aquitards as important sources of recharge in regional scale, multi-aquifer systems.
On the predictability of the Madden-Julian Oscillation phase 
Authors: Silini Riccardo , Masoller Cristina , Barreiro Marcelo
Published: March 2021

Climate extremes such as heat waves, drought, extreme precipitation or cold surges have huge social and economic impacts that are expected to increase with climate change. Forecasting of such extreme events on the sub-seasonal time scale (from 10 days to about 3 months) is very challenging because of the poor understanding of phenomena that may increase predictability at this time scale. The Madden-Julian Oscillation (MJO) is the dominant mode of variability in the tropical atmosphere on sub-seasonal time scales and can also promote or enhance phenomena such as monsoons and hurricanes in other regions of the world. It is a hierarchically organized structure that propagates across the planet with a period of 30 to 60 days, and its phase represents an important source of sub-seasonal predictability. For this reason, forecasting the MJO phase can improve the predictability of weather extremes. Here we use the index of the MJO based on outgoing longwave radiation (OLR), namely the OLR MJO Index (OMI), which is a popular index used for defining MJO phases. We used the first two principal components to compute the MJO phase and amplitude. With an autoregressive integrated moving average (ARIMA) model we found that winter and summer are slightly more predictable than spring and autumn. We also computed the likelihood of having a warm/cold spell during a given MJO phase. For warm spells, we found that the significantly most likely phase is the 7, and the top three are 7, 8 and 1, which are, as expected, consecutive phases. For cold spells, phases 5 and 1 play important roles, while phase 3 is by far the least likely to have cold spells. Ongoing work is devoted to compare the skill of neural network approaches (long-short term memory, LSTM, and gated recurrent unit, GRU) for the prediction of the MJO phases and warm/cold spells. Acknowledgment: work funded by ITN CAFE.
Paleo-ENSO impacted habitat availability for early modern humans
Authors: Kaboth-Bahr Stefanie , Gosling William D. , Vogelsang Ralf , Bahr André , Scerri Eleanor M.L. , Asrat Asfawossen , Cohen Andrew S. , Düsing Walter , Foerster Verena E. , Lamb Henry F. , Maslin Mark A. , Roberts Helen M. , Schäbitz Frank , Trauth Martin H.
Published: March 2021

In this study we synthesize terrestrial and marine proxy records spanning the last 620,000 years, to decipher pan-African climate variability, its drivers and potential linkages to hominin evolution. We find a tight correlation between moisture availability across Africa to Walker and Hadley Circulation variability that were most likely driven by changes in Earth´s eccentricity. Our results demonstrate that low latitude insolation rather than glacial-interglacial cyclicity was the predominant driver of pan-African climate change during the mid to late Pleistocene. We argue that these low-latitude climate processes governed the dispersion and evolution of vegetation, as well as mammals, in eastern and western Africa, ultimately by increasing resource-rich and stable ecotonal settings that have long thought to have been the preferred habitats of hominins.
Effect of precipitation mineralization reactions on convective dissolution of CO2 : an experimental study
Authors: De Wit Anne , Thomas Carelle , Dehaeck Sam
Published: March 2021

To analyze the influence of a precipitation mineralization reaction between dissolved CO2 and calcium ions on the convective transfer of CO2 towards an aqueous phase, the convective dissolution of CO2 into aqueous solutions of calcium hydroxyde (Ca(OH)2) and calcium chloride (CaCl2) of various concentrations is studied experimentally. We show that different precipitation patterns develop in the aqueous solution depending on the nature and concentration of the reactant in the host phase. In the case of Ca(OH)2, precipitation coupled to convection leads to vigorous convective mixing in the host phase and sedimentation of solid particles of calcium carbonate (CaCO3) down to the bulk of the reservoir. Conversely, dissolution of CO2 in buffered CaCl2 solutions leads to a stabilisation of the buoyancy-driven convection due to a decrease in density and the adherence of the precipitate to the cell walls.
Development of interactive diagnostic tools and metrics for the socio-economic consequences of floods
Authors: Parent Annie-Claude , Fournier Frédéric , Anctil François , Morse Brian , Baril-Boyer Jean-Philippe , Marceau Pascal
Published: March 2021

Spring floods have generated colossal damages to residential areas in the Province of Quebec, Canada, in 2017 and 2019. Government authorities need accurate modelling of the impact of theoretical floods in order to prioritize pre-disaster mitigation projects to reduce vulnerability. They also need accurate modelling of forecasted floods in order to direct emergency responses. 

We present a governmental-academic collaboration that aims at modelling flood impact for both theoretical and forecasted flooding events over all populated river reaches of meridional Quebec. The project, funded by the ministère de la Sécurité publique du Québec (Quebec ministry in charge of public security), consists in developing a diagnostic tool and methods to assess the risk and impacts of flooding. Tools under development are intended to be used primarily by policy makers. 

The project relies on water level data based on the hydrological regimes of nearly 25,000 km of rivers, on high-precision digital terrain models, and on a detailed database of building footprints and characterizations. It also relies on 24h and 48h forecasts of maximum flow for the subject rivers. The developed tools integrate large data sets and heterogeneous data sources and produce insightful metrics on the physical extent and costs of floods and on their impact on the population. The software also provides precise information about each building affected by rising water, including an estimated cost of the damages and impact on inhabitants.  
Modeling groundwater table and runoff in self-organizing hydrologically sensitive areas
Authors: Brindt Naaran , Pacenka Steven , Richards Brian K. , Steenhuis Tammo S.
Published: March 2021

Understanding the hydrology of hydrologically sensitive areas (or runoff source areas) is crucial for evaluating and predicting runoff and the environmental fate of applied chemicals. However, while modeling these areas, one must deal with an overwhelmingly complex, coupled nonlinear system with feedbacks that operate at multiple spatiotemporal scales. Sufficient detailed information on the physical environment that these models represent is often not available. Consequently, the simulation's results, even after extensive calibration, are often disappointing. Fortunately, self-organization of hydrological systems' makes it possible to simplify watershed models and consider the landscape functions instead of small-scale physics. These simplified (or surrogate) models provide the same or better objective results than their complex counterparts, are much less data-intensive, and can be used for engineering applications and planning purposes.

This study aims to experimentally expose the landscape hydrological self-organization of a periodically saturated variable source area with a shallow perched water table and a humid climate. The study site is a four-hectare runoff source area near Cornell University, Ithaca, NY, US. The saturated hydraulic conductivity is greater than the rainfall intensity. The area has a single outlet through a notched weir, and the only inflow is from precipitation. We analyzed observed water table heights and field outflow and found the theory behind the self-organization of runoff processes specific to that landscape type. We determined a priori the thresholds for runoff in a surrogate model using the soil moisture retention curve. 

Weir measurements showed that outflow on the day following rainfall had decreased by orders of magnitude, indicating the soil water had returned to static equilibrium. Under the equilibrated state, established theory indicates that the matric potential decreases linearly with depth above the shallow groundwater. The matric potential (and thus the retention curve) determined the soil water distribution. Another property from the whole field perspective is that excess rainfall above saturation becomes runoff.

The reason for self-organization of the source area was that the soil moisture retention curve (which is similar for the whole source area) determined daily both the soil moisture content and the water table change using rainfall and evaporation as drivers. Since the source area behaved similarly, a simple surrogate water balance could predict the aggregated area's hydrological behavior. The nonlinear and small-scale physics associated with the field's complexity determined the rate that equilibrium is reached, which is always less than one day due to high macropore conductivity, greatly simplifying surrogate models that make daily predictions.