bluuebunny/crossref_metadata_2025 huggingface dataset:
Uncertainty quantification for melt rate parameters in ice shelves using simulation-based inference
Authors: Moss Guy , Višnjević Vjeran , Schröder Cornelius , Macke Jakob , Drews Reinhard
Published: March 2022

Mass loss from the Antarctic ice sheet is dominated by the integrity of the ice shelves that buttress it. The evolution and stability of ice shelves is dependent on a variety of parameters that cannot be directly observed, such as basal melt and ice rheology. Constraining these parameters is of great importance in making predictions of the future changes in ice shelves that have a quantifiable uncertainty. This inference task is difficult in practice as the number of unknown parameters is large, observations are often sparse, and the computational cost of ice flow models is high.

We aim to develop a framework for inferring joint distributions of mass balance and rheological parameters of ice shelves from observations such as ice geometry, surface velocities, and radar isochrones. Here, we begin by inferring a posterior distribution over basal melt parameters in along-flow sections of synthetic and real world ice shelves (Roi Baudouin). We use the technique of simulation-based inference (SBI), a machine learning framework for performing Bayesian inference when the likelihood function is intractable. The inference procedure relies on the availability of a simulator to model the dynamics of the ice shelves. For this we use the Shallow Shelf Approximation (SSA) implemented in the Python library Icepack.  First, we show that by combining these two tools we can recover the underlying parameters of synthetic 2D data with meaningful uncertainty estimates. In a second step, we apply our method to real observations and get estimates for the basal melt rates which are coherent with the data when running the forward model over a centennial timescale.
Salinity-inclusive water scarcity: examples from food bowl regions of the US and Australia
Authors: Thorslund Josefin , Bierkens Marc F.P. , Scaini Anna , Sutanudjaja Edwin H. , van Vliet Michelle T.H.
Published: March 2022

Irrigated agriculture sustains more than 40% of global food production and uses up to 90 % of the world’s water resources. Water scarcity for the irrigation water use sector is a common problem, which may be driven by both water shortages and increased salinity levels. Limited studies however considered salinity issues in water scarcity assessment. We here developed a salinity-inclusive water scarcity framework for the irrigation sector, accounting for crop-specific irrigation water demands and salinity tolerance and its relation to water availability and salinity levels of both surface and groundwater resources. We assess temporal and spatial variation of water scarcity in agricultural river basins of the Central Valley (California) and the Murray Darling Basin (Australia), which are important food bowl regions. Our results show that including salinity and crop-specific salinity tolerances leads to very different water scarcity levels, compared to water scarcity approaches based on water quantity only, particularly at local scales. Further, our results from the Central Valley region highlights that severe water scarcity can be strongly alleviated by conjunctive groundwater use, to dilute and lower salinity levels below crop specific tolerance values in many sub-basins. However, groundwater resources needed for dilution frequently exceed renewable groundwater rates in this region, posing additional risks for groundwater depletion. Taken together, through capturing these dynamics, our water scarcity framework can support local-regional water management and provide a useful tool for sustainable water use and assessing the impact of agricultural practices, such as crop choices, on water scarcity levels.
Air Quality: From Science to Action
Authors: Brasseur Guy , Li Cathy , Granier Claire , Doumbia Thierno , Sofiev Mikhail , Timmermans Renske , Pfister Gabriele , Kumar Rajesh , Basart Sara , Salvi Olivier , Caillard Bastien , Boose Yvonne
Published: March 2022

The AQ-WATCH (Air Quality: Worldwide Analysis and Forecasting of Atmospheric Composition for Health) project, supported by the European Commission, is developing seven innovative products and services for improving air quality forecasts and attributing chemical sources. These prototypes are based on existing space and in-situ observations of air quality. They are tailored to the identified needs of international users and are aimed at improving public health. The prototypes include (1) a global and regional air quality atlas, (2) a forecast system for metropolitan areas, (3) a wildfire and visibility service, (4) a dust and solar energy service, (5) a pollution from fracking service, (6) an emission mitigation service and (7) an attribution service. The prototypes are being tested by prime users and integrated in a user-friendly toolkit. These products and services will be brought to the market.
Ion dynamics in the inner magnetosphere during Van Allen Probe Era
Authors: Yue Chao
Published: March 2022

Ion dynamics are controlled by the energy-dependent source, transport, energization, and loss processes. Systematic changes in the ion dynamics are essential to understand the ring current variations in the inner magnetosphere. The Van Allen Probes mission, which orbits near the equatorial plane inside the geosynchronous orbit, has a wide energy coverage with high energy resolution and state-of-the-art ion composition instrumentation. It provides a great opportunity to investigate plasma dynamics. In this talk, I will present some of our recent studies on the ion dynamics of different populations and species as well as the related plasma wave activity during geomagnetic quiet and active times.
A globally consistent approach for basic service disruptions after natural disasters
Authors: Mühlhofer Evelyn , Koks Elco , Sansavini Giovanni , Bresch David N.
Published: March 2022

Critical infrastructures (CIs) such as powerlines, roads, telecommunication and healthcare systems across the globe are more exposed than ever to the risks of extreme weather events in a changing climate. Damages to CIs often lead to failure cascades with catastrophic impacts in terms of people being cut off from basic service access. Yet, there is a gap between traditional CI failure models, operating often at local scales, with detailed proprietary, non-transferrable data, and the large scales and global occurrences of natural disasters.

We demonstrate a way to bridge those incompatibilities by linking a globally consistent and spatially explicit natural hazard risk modelling platform (CLIMADA) and a CI failure cascade model. The latter is built on publicly available infrastructure, end-user and supply data, and makes use of consistent and transferrable dependency heuristics between CIs to represent infrastructure systems at national scales for any place interest. Impacts are then spatially mapped in terms of people experiencing disruptions to basic service access.

With this approach, we aim to showcase how the interplay of available data and well-informed heuristics can allow large-scale impact models to produce consistent hot-spot analyses and rapid emergency assessments, which may then provide a starting point for more detailed, local studies.
Investigating the influence of climate on Surface Urban Heat Island (SUHI) behaviour
Authors: Berk Sarah , Goodess Clare , Joshi Manoj
Published: March 2022

As centres of human activity, cities contain over half the world’s population and this proportion is projected to increase to around 70 percent in 2050. The urban heat island (UHI) is a well observed phenomenon, where temperature in a city is warmer than the surrounding rural area.

The UHI is influenced by both the climate and the morphology of the city. Focusing on cities in the tropics and subtropics and those with a population of less than 1 million, this research explores the relationship between the UHI effect and climate. Cities in different climate zones are selected based on similar characteristics such as population, variation of elevation within the city and surrounding area, and proximity to water bodies. Satellite data, with global coverage, is used to quantify the SUHI of the chosen cities. Peak SUHI was calculated using the Gaussian Surface Approximation methodology and the mean SUHI defined as the mean land surface temperature of urban pixels minus the mean of the surrounding rural area.  

Statistical techniques including Multiple Linear Regression, Random Forest Regression and Gaussian Process Regression are used to find relationships between SUHI and variables such as vegetation greenness (EVI), evaporative fraction, precipitation, incoming solar radiation, and city area. 
Incorporating vegetation dynamics for terrestrial isoprene and monoterpene emission estimates: Linking LPJ-GUESS (v4.0) with the EMAC modelling system (v2.54) 
Authors: Vella Ryan , Forrest Matthew , Lelieveld Jos , Tost Holger
Published: March 2022

Earth system models (ESMs) are state-of-the-art models which integrate previously separate models of the ocean, atmosphere and vegetation in one comprehensive modelling system enabling the investigation of interactive feedbacks between different components of the Earth system. Global isoprene and monoterpene emissions from terrestrial vegetation, which represents the most important source of VOCs in the Earth system, are needed for a suitable representation in global and regional chemical transport models given their impacts on the atmosphere. Consequently, to accurately determine the budget of isoprene and monoterpenes in the atmosphere, adequate emissions from the terrestrial vegetation are a requirement for input into regional and global scale chemistry-transport or chemistry-climate models. Due to the feedbacks of vegetation activity involving interactions with the weather and climate, a coupled modelling system between vegetation and atmospheric chemistry is a recommended tool to address the fate of biogenic volatile organic compounds (bVOCs). In this work, we present further development in linking LPJ-GUESS, a global dynamic vegetation model, to the atmospheric chemistry-enabled atmosphere-ocean general circulation model EMAC. We evaluate terrestrial bVOC emission estimates from the submodel ONEMIS in EMAC with (1) prescribed climatological vegetation boundary conditions at the land-atmosphere interface; and (2) dynamic vegetation states calculated in LPJ-GUESS (replacing the “offline” vegetation inputs). LPJ-GUESS-driven global emission estimates for isoprene and monoterpenes were found to be 599 Tg yr−1 and 111 Tg yr−1, respectively. Additionally, we evaluated the sensitivity of the new coupled system in doubling CO2 scenarios. Higher temperatures resulted in an increase in bVOC emissions (+47% and +69% for isoprene and monoterpenes, respectively), whereas CO2-fertilisation resulted in an increase of 18% in isoprene emissions and 37% in monoterpene emissions. We provide evidence that the new coupled model yields suitable estimates for global bVOC emissions that are responsive to vegetation dynamics, thus enabling further research in land-biosphere-atmosphere interactions.
The daily-resolved Southern Ocean mixed layer: regional contrasts assessed using glider observations
Authors: du Plessis Marcel , Swart Sebsastiaan , Biddle Louise C. , Giddy Isabelle S. , Monteiro Pedro M.S. , Reason Chris , Thompson Andrew F. , Nicholson Sarah A.
Published: March 2022

Water mass transformation in the Southern Ocean is vital for closing the large-scale overturning circulation, altering the thermohaline characteristics of upwelled Circumpolar Deep Water before returning to the ocean interior. Using profiling gliders, this study investigates how buoyancy forcing and wind-driven processes lead to intraseasonal (1-10 days) variability of the mixed layer temperature and salinity in three distinct locations associated with different Southern Ocean regions important for water mass transformation - the Subantarctic Zone (SAZ, 43°S), Polar Frontal Zone (PFZ, 54°S) and Marginal Ice Zone (MIZ, 60°S). Surface heat fluxes drive the summertime mixed layer buoyancy gain in all regions, particularly evident in the SAZ and MIZ, where shallow mixed layers and strong stratification further enhance mixed layer warming. In the SAZ and MIZ, the entrainment of denser water from below is the primary mechanism for reducing buoyancy gain. In the PFZ, turbulent mixing by mid-latitude storms result in consistently deep mixed layers and suppressed mixed layer thermohaline variability. Intraseasonal mixed layer salinity variability in the polar regions (PFZ and MIZ) is dominated by the lateral stirring of meltwater from seasonal sea ice melt. This is evident from early summer in the MIZ, while in the PFZ, meltwater fronts are proposed to be dominant during late summer, indicating the potential for seasonal sea ice freshwater to impact a region where the upwelling limb of overturning circulation reaches the surface. This study reveals a regional dependence of mixed layer thermohaline properties to small spatio-temporal processes, which suggests a similar regional dependence to surface water mass transformation in the Southern Ocean.
TOPAZ4b: a new version of the ocean and sea-ice Arctic reanalysis
Authors: Xie Jiping , Bertino Laurent
Published: March 2022

The second version of the Arctic ocean and sea ice reanalysis is based on the coupled ensemble data assimilation system (TOPAZ4b). Compared to its predecessor (Xie et al. 2017) it has benefited from enhancements to observation, model vertical resolution, and forcing datasets. TOPAZ4 relies on version 2.2 of the HYCOM ocean model and the ensemble Kalman filter data assimilation using 100 dynamical members. A 30-years reanalysis of the Arctic ocean and sea ice has been completed starting in 1991, and made available as the multi-year physical product by the Arctic Marine Forecasting Center (ARC MFC) under the Copernicus Marine Environment Monitoring Service. Contrary to the previous version of the Arctic reanalysis, the systematic errors due to fragmented time series of assimilated observations have been removed by using consistent ESA CCI data. The comparison to in situ profiles shows that the temperature and salinity stratification has been considerably improved by the increased vertical resolution in HYCOM, for example in the East Greenland Sea, the temperature root mean square error (RMSE) from surface to 1400 m has been reduced by 50%. These improvements encourage the use of this Arctic reanalysis for climate studies.
Contribution of phosphorus transported by atmosphere to the East China Sea in summer
Authors: Tian Rongxiang , Zhao Xiuyi
Published: March 2022

Phosphorus is an important nutrient for the growth of marine life in the East China Sea(ECS), where phosphorus is restricted. The external input of phosphorus may cause changes in primary productivity and result in harmful algal blooms. Previous studies emphasized the important contribution of diluted water from the Yangtze River and Kuroshio current. Few researches focus on the sudden and large atmospheric input. Supported by the National Natural Science Foundation of China Open Research Cruise, we collected seawater samples, measured the oxygen isotopes of phosphate and then quantitatively analyze the contribution rate of phosphate from different sources. The results are found that atmospheric input is the main source of phosphorus in the northeast of the East China Sea and the main source of phosphate is from Taiwan Warm Current in the southwest part of the ECS. This finding is helpful for exploring the influencing factors of harmful algal blooms in the ECS and providing some ideas of solution.
Practical implementation of the IHRF employing local gravity data and geoid models
Authors: Barzaghi Riccardo , Vergos Georgios
Published: March 2022

With the definition of the International Height Reference System (IHRS) and the development of a roadmap for its implementation through the International Height Reference Frame (IHRF), an analytical evaluation of the various approaches for the practical determination of potential values at IHRF is necessary. In this work we focus on two main approaches to estimate geopotential values at IHRF stations. The first approach resides on the use of either local gravity anomalies and gravity disturbances around each site and the geopotential determination based on Stokes’ and Molodensky’s boundary value problems, respectively. In this scheme, the influence of the classical residual terrain model (RTM) reduction as well as that of RTM effects based on spherical harmonics expansion of the topographic potential are investigated. Furthermore, the introduction of possible biases within the various pre- and post-processing steps are thoroughly investigated, as e.g., during the estimation of station geometric heights, along with the influence of the quasi-geoid to geoid separation estimation. In the second approach, we investigate the determination of geopotential values based on either national and regional geoid models, i.e., resembling the case that access to local gravity data is not available, and the determination has to be based on some available geoid model. In the present work we analyze the theoretical and methodological steps that need to be followed in each approach, identifying the possible sources of biases. Finally, some early results are presented aiming at providing a roadmap and an error assessment for the practical realization of the IHRF.
Structural setting, active tectonics and seafloor morphology of the northeastern Calabria accretionary prism (Ionian Sea, Italy) 
Authors: Lipparini Lorenzo , Argnani Andrea , Sgattoni Giulia , Pellegrini Claudio , Rovere Marzia , Molinari Irene
Published: March 2022

The Calabrian accretionary prism is the result of a complex interaction between subduction-related tectonics and sedimentation, active since the Eocene. The limited seismicity recorded in recent years in the area appears mostly associated to the subduction interface and could reflect either a weak subduction coupling or a slow subduction rate. Nevertheless, recent intense deformation and uplift of the seafloor has been observed within the accretionary prism.

The analysis of multichannel 2D and high-quality 3D seismic data, morphobathymetric data and instrumental seismicity, allows defining and characterizing both the deeper and shallower tectonic deformation affecting the northeastern sector of the Calabrian accretionary prism. 

Besides the uppermost thrust fault of the Calabrian accretionary prism, that outlines the Crotone promontory, the shallow tectonic pattern of the prism is characterized by a belt of broad flat-topped anticlines, and a set of minor narrow structures, mainly NNW-SSE to N-S oriented, that present a variable relationship with the underlying main thrust faults. The uppermost sedimentary strata within the anticlines are affected by numerous small-scale extensional faults, not rooted at depth, likely due to outer-arc extension above uplifted depocenters. In places, the inversion of basin-bounding faults is also visible. More regularly spaced and cylindrical NW-SE anticlines are also observed in the Gulf of Taranto, in the outer sector of the accretionary prism, where a thrust/back-thrust tectonic style is present. The origin of the anticlines varies within the overall set and reflects the long-term tectonic evolution of the accretionary prism, with the oblique docking of the Calabrian accretionary prism onto the Apulian Escarpment as a key feature.
Compound Hot-Dry Events in Urban India: Variability and Drivers
Authors: Ganguli Poulomi
Published: March 2022

The precipitation deficit-temperature feedback can severely impact multiple sectors, such as reduction in crop yield to critical infrastructure failures, especially in low latitude areas (< 30°N). Typically, a heatwave event coincides with a significant decline in surface wind speed due to atmospheric blocking and is often compounded by persistent precipitation-deficit leading to meteorological droughts. Anomalous warm-and-dry air, which comes in torrents, results in an abrupt increase in air temperature that strengthens the local land-atmosphere feedback via soil desiccation. Based on daily meteorological observations covering the 1970-2018 period, first, I show a spatial coherence in the timing of unprecedented hot-dry events over major urban and peri-urban locations of the Indian sub-continent (8°4'N and 37°6'N). Surface wind data confirms a significant decline in low wind speed over most of the locations, especially over the eastern coastal plains of the country. Further, the compound occurrence of extreme temperature and low wind speed act as a preconditioning driver for sequential short (or long)-duration precipitation deficits across most of the sites. A copula-based joint distribution framework incorporating the compounding effect of high temperature, low wind speed, and precipitation deficit reveals a T-year severe hot-dry event tends to become more frequent. Finally, I show a median 6-fold amplifications in compound hot-dry frequency than that of the expected annual number of 50-year temperature extreme. The inferred amplifications are more pronounced in low-lying urban-coastal areas than in the interior locations, where decadal changes in (significant) increase in extreme temperature at several locations are contrasted by a concurrent decrease in surface wind speed.  
The value of InSAR Coherence in TanDEM-X and Sentinel-1 for monitoring world’s forests
Authors: Rizzoli Paola , Bueso-Bello José-Luis , Dal Molin Ricardo , Carcereri Daniel , Gonzalez Carolina , Martone Michele , Dell'Amore Luca , Gollin Nicola , Milillo Pietro , Zink Manfred
Published: March 2022

Covering about 30 percent of the Earth’s surface, forests are of paramount importance for the Earth’s ecosystem. They act as effective carbon sinks, reducing the concentration of greenhouse gas in the atmosphere, and help mitigating climate change effects. This delicate ecosystem is currently threatened and degraded by anthropogenic activities and natural hazards, such as deforestation, agricultural activities, farming, fires, floods, winds, and soil erosion. In an era of dramatic changes for the Earth’s ecosystems, the scientific community urgently needs to better support public and societal authorities in decision-making processes. The availability of reliable, up-to-date measurements of forest resources, evolution, and impact is therefore of paramount importance for environmental preservation and climate change mitigation.

In this scenario, Synthetic Aperture Radar (SAR) systems, thanks to their capability to operate in presence of clouds, represent an attractive alternative to optical sensors for remote sensing over forested areas, such as tropical and boreal forests, which are hidden by clouds for most of the year.

In this work, we will investigate the potential of SAR interferometry (InSAR) for mapping forests worldwide and retrieve important biophysical parameters, such as canopy height and above ground biomass. We will compare pros and cons of single-pass (bistatic) versus repeat-pass InSAR, discussing their main peculiarities and limitations. In particular, we will concentrate on the analysis of the interferometric coherence and on the relationship between volume and temporal decorrelation with respect to forest parameters estimation. We will present the work done at DLR for mapping forests worldwide at high spatial resolution using the TanDEM-X bistatic coherence, together with the potential of Sentinel-1 InSAR time-series for a regular monitoring of vegetated areas. We will discuss the algorithms which currently under development for the estimation of above ground biomass, by fusion of InSAR and multi-spectral optical data, based on the latest advances in the field of artificial intelligence and, in particular, of deep learning, presenting the first promising results for a more effective exploitation of current EO datasets.

 
Feature-based clustering of hydroclimatic time series
Authors: Papacharalampous Georgia , Tyralis Hristos
Published: March 2022

Both the grouping of hydroclimatic time series (often required, e.g., for technical and operational purposes) and the identification of spatial hydroclimatic patterns can be formalized and automated through algorithmic clustering methodologies. In this presentation, we focus on a new family of such methodologies that can be applied to various types of hydroclimatic variables (e.g., temperature, precipitation and streamflow) and at various temporal scales (e.g., the daily, monthly, seasonal, annual and climatic ones) with minimal adaptations. Aiming to exploit the largest part possible of the total information encompassed in the hydroclimatic time series, this family of clustering methodologies primarily relies on massive feature extraction, a concept sourced from the data science field. Once a compilation of numerous and diverse time series features (comprising autocorrelation, long-range dependence, entropy, temporal variation, seasonality, trend, lumpiness, stability, nonlinearity, linearity, spikiness, curvature and more features) has been computed, the clustering upon them is performed using a selected machine and statistical learning algorithm, with unsupervised random forests being an appealing choice for the task. Explainable machine learning can also be applied, as part of wider methodological frameworks, for ranking the features from the most to the least informative ones in obtaining the clusters, thereby facilitating the interpretability of the clustering outcomes in a comprehensive manner. We extensively discuss the above-outlined approach to hydroclimatic time series clustering emphasizing its main similarities and differences with the current well-established approaches in hydrology (e.g., from the catchment hydrology field), as well as its strengths and current limitations. Our discussions are well-supported by global-scale and other large-scale investigations, which have been conducted for temperature, precipitation and streamflow variables at several temporal scales.
A simple low-cost Arduino based LoRaWAN automatic weather station 
Authors: Müller Tom , Schaefli Bettina , Lane Stuart N.
Published: March 2022

With a rapid increase in the use of low-cost DIY Arduino solutions, many companies are providing low cost sensors for practically any environmental applications and new users can also benefit from a rich virtual community proposing diverse solutions and tutorials. Nowadays, these new hardware solutions, as well as more robust communication protocols, allow to design very simple almost plug-and-play automatic dataloggers.

In this talk we will discuss three simple datalogger solutions developed in the framework of a field campaign in a harsh proglacial environment in the Swiss Alps. The first solution consists of a simple autonomous datalogger (based on Seeeduino Stalker board) designed to record piezometric heads in wells, even during the winter cold season. The second station consists of two alternative main boards (SODAQ and CubeCell) that were used to develop a connected LoRaWAN automatic weather station to monitor air temperature and precipitation on the glacier. Connected to a base station LoRaWAN gateway (Dragino), this system successfully allowed for a remote monitoring of those parameters.

In a first step, we will quickly go through the main components of each system and detail the basic LoRaWAN architecture. We will then mostly focus on the practical deployment of these solutions in the field and discuss their potential and challenges. We will try to show a live demonstration of their functioning and will insist on the relative technical simplicity and low-cost of such solutions, which could be replicated for many other environmental applications. We will finally discuss the pros and cons of these solutions compared to professional senor companies.
Multivariate water environmental risk analysis in long-distance water supply project: A case study in China
Authors: Nong Xizhi , Zhang Chi , Shao Dongguo , Zhong Hua , Shang Yuming , Liang Jiankui
Published: March 2022

The variation of water quality in long-distance water supply projects is often different from that in natural water bodies, especially the environmental risks of artificial open canal water transfer projects are seldom studied. The spatial heterogeneity of algae growth and the absence of universal reference standards for algae control often lead to water quality problems in these projects. The Middle Route (MR) of the South-to-North Water Transfer Project of China (SNWTPC), the world’s largest inter-basin water transfer project, has operated stably for six years. Its water resources have benefited more than 60 million people and an ecosystem cover more than 160,000 km2. To understand the water environment risk of this mega hydro-project, this study focused on the relationships among three key parameters: water temperature (T), water discharge (Q), flow rate (V) and analyzed the spatial–temporal variation characteristics of the algal cell density (ACD) in the MR of the SNWTPC from January 2016 to December 2018, 36 months in total. The Copula functions were applied to identify and evaluate the multivariate risk variation of the water environment. Our result demonstrated that there was a significant positive correlation between T and ACD, and the ACD at the downstream has a 50% risk higher than 700 × 104 cell/L in summer. Overall, the water quality status of the MR of the SNWTPC is quite well, and the ACD kept at an average level of 106 cells/L during the monitoring period. Additionally, the ACD increased from upstream to downstream, showing the relatively higher ACD in summer and autumn than in spring and winter, with the ranges of 500 ~ 700 × 104 cells/L and 200 ~ 300 × 104 cells/L, respectively. The water temperature affected the ACD over the early-warning thresholds at different canal sections were as follows: 29, 26, and 21℃ from upstream to downstream, respectively. The influences of the hydrodynamic factors, water discharge and flow rate, impact on the ACD variation were analyzed to achieve the purpose of specific algae control for different canal reaches. Our study verified that the growth probabilities of the ACD under higher water temperature and water discharge in the MR of the SNWTPC than other natural water bodies.
Relative contribution of afterslip, non-linear viscous, and poroelastic processes to the early postseismic deformation field of the 2010 Maule earthquake
Authors: Peña Carlos , Metzger Sabrina , Heidbach Oliver , Bedford Jonathan , Bookhagen Bodo , Moreno Marcos , Oncken Onno , Cotton Fabrice
Published: March 2022

Large earthquakes impose differential stresses in the crust and upper mantle that are transiently relaxed during the postseismic phase mostly due to afterslip on the fault interface, viscoelastic relaxation in the lower crust and upper mantle, and poroelastic rebound in the upper crust. During the last years, the wealth of geophysical and geodetic observations, as well as great effort in forward and inverse modelling have allowed a better comprehension of the role of these mechanisms during the postseismic period. However, it is still an open question to what extent postseismic processes contribute to the surface deformation signal, especially during the early postseismic period. In this study, we use GNSS and InSAR observations collected in the first 48 days following the 2010 Maule earthquake in Chile along with a model approach that integrates afterslip, poroelasticity, and temperature-controlled power-law (non-linear viscosity) rheology. The afterslip distribution is obtained from a geodetic data inversion after removing the poro-viscoelastic component by forward modelling to the geodetic data. We find that our model approach explains the geodetic cumulative signal 14% better than a pure elastic model inverting for afterslip. This improvement is mainly produced by the better fit to the geodetic signal at the volcanic and back-arc regions due to the inclusion of non-linear viscoelastic processes, which can explain > 60% of the observed surface displacements in these regions. We also show that poroelastic processes play a significant role locally, specifically near the region where the coseismic slip was largest. Here, poroelastic processes explain most of the cumulative observed GNSS uplift signal and produce surface landward patterns that affect the horizontal GNSS component by up to 15% in the opposite direction. If poroelastic processes are ignored, our results reveal that the resulting afterslip amplitude is both amplified and suppressed by up to 40% in regions of ~50 x 50 km2. Our findings have implications for the calculation of the postseismic slip budget, and therefore the seismic hazard assessment of future earthquakes.
Choosing academia: an outsider's perspective
Authors: Talavera-Soza Sujania , Deuss Arwen
Published: March 2022

Choosing academia as a career path is a luxury and privilege of the few. The place where you are born and the citizenship you hold can determine whether an academic career is possible as a life goal. Here, I will detail my own personal experiences and explain how I arrived to geosciences and seismology as a woman of color from a developing country (Nicaragua). These experiences have been shaped by me living in Mexico, Germany and the Netherlands, as well as by key personal choices and important mentors that have taken me from an industry job as an engineer to a postdoc.
Anatomy of a dying spreading ridge: paleomagnetic evidence for horizontal axis rotations in the Troodos Ophiolite, Cyprus
Authors: Advokaat Eldert , Maffione Marco , Burton-Johnson Alex , Dekkers Mark
Published: March 2022

The Troodos ophiolite of Cyprus hosts a fossil spreading ridge at the Solea graben, whose last magmatic activity has been previously dated to 94.3±0.5 Ma. To study the evolution of a dying ridge, we collected structural geologic data and oriented specimens from the mantle section (serpentinized peridotites, pegmatitic dykes, pyroxenite and wehrlite intrusions) and lower crust (layered gabbros and massive gabbros) for paleomagnetic and rock magnetic analyses. Our results revealed a systematic pattern of horizontal axis rotations (i.e., tilt) in the region to the west of the Solea spreading axis, involving upper crust, lower crust, and upper mantle. Horizontal axis rotations vary in magnitude between ~20° to ~90° within the studied area, with the largest tilts observed to the west of the exposed mantle section at Mt. Olympus, and the smallest tilts observed near the NNW-SSE trending Troodos Forest-Amiandos fault system. This rotation pattern conflicts with previous interpretations considering the Troodos Forest-Amiandos fault as an oceanic detachment, and rather indicates the existence of deep-rooted listric faults that dismembered the Solea spreading ridge after the final phase of spreading.

 

Paleomagnetic directions from serpentinized peridotites indicate that serpentinization occurred both before and during dismemberment of the ridge by listric faulting. As these directions also record a well-studied regional 90° counter-clock-wise rotation of the Troodos ophiolite, we constrained the timing of ridge dismemberment and associated serpentinization between ~94 Ma and the beginning of the regional microplate rotation in the Turonian, hence encompassing a relatively short period of time of 2-4 Myr that well coincides with hydrothermal alteration in nearby plagiogranites dated at ~92–90 Ma.
Continental Rifting Advances Using 3D Computational Modeling of Lithospheric Deformation, Asthenospheric Flow, and Deep Melt Generation with ASPECT 
Authors: Stamps D. Sarah , Njinju Emmanuel , Kwagalakwe Asenath , Naliboff John , Rajaonarison Tahiry
Published: March 2022

Continental rifting processes are influenced by viscous coupling of the deforming lithosphere to asthenospheric flow, as well as magma that migrates upward from the upper asthenosphere. Over the past few decades, significant advances have been made in finite element numerical methods that enable modeling of lithospheric deformation, viscous coupling to asthenospheric flow, and melt generation in the upper asthenosphere. In this work, we present new developments based in the NSF Computational Infrastructure for Geodynamics finite element code ASPECT (Advanced Solver for Problems in Earth’s Convection) that allow users to investigate lithospheric deformation, asthenospheric flow, and melt generation in the upper asthenosphere. Users have the options to constrain their initial temperature and density conditions with laterally varying lithospheric thickness, layers of crustal thickness, and shear wave seismic velocity models in the sublithospheric mantle. We present case studies from regions along the East African Rift System that demonstrate these capabilities. 
Structure, strain partitioning and exhumation mechanism during the late stage oblique tectonic evolution of the Variscan Tanneron massif (SE France)
Authors: Gremmel Josselin , Duclaux Guillaume , Corsini Michel , Maillet Abel , Jourdon Anthony , Bascou Jerome
Published: March 2022

Oblique tectonic, including transpressional and transtensional movements, is a common feature observed at active plate boundaries. Despite being often inferred at the orogen scale, the interpretation of local structural observations in the context of oblique tectonic regimes remains challenging, especially in ductile terrains. During the last stage evolution of orogenic belts, obliquity is expected to play a key role in controlling strain partitioning and exhumation patterns of deep crustal rocks, as well as the development of brittle structures in the upper crust.

Here, we present new structural data and finite strain analyses of migmatitic rocks exposed in the Tanneron Massif in SE France. This massif, representing the most internal part of the Maures-Tanneron Variscan belt segment, was structured between 320 and 300 Ma during the late stage Variscan orogeny. This late-stage deformation, synchronous to partial melting of the middle crust, the large-scale folding of the migmatitic units and their exhumation has been interpreted to take place in a regional transpressive regime.

New detailed structural mapping carried on in two sectors of the massif highlight different strain patterns with dome-like structures in a migmatite unit to the East, and sub-vertical shear-zones with stretching lineation to the West. However, in these two sectors stretching is dominant and finite constrictional fabrics are ubiquitous. The regional lineation, corresponding to the maximum stretching direction of these L-tectonites is parallel to the large scale and local fold axes. In addition, narrow continental Carboniferous basins oriented roughly parallel to the main ductile fabric opened inside the massif contemporaneously to the exhumation of the L-tectonites. Therefore, our results suggest that local transtension might best describe the tectonic regime associated with the late-stage evolution of the massif. We will discuss these results for the Tanneron massif in the light of a series of preliminary 3D thermo-mechanical numerical models designed to investigate the horizontal and vertical partitioning of deformation in a hot orogen subject to regional oblique deformation.
Intercomparison of reanalysis products during extreme flood and drought events: evaluation over the major river basins of Africa
Authors: Abdelmoneim Hadir , Eldardiry Hisham
Published: March 2022

Data availability and accuracy is predominantly an issue for building hydrological applications, particularly in data-scare regions, like Africa. This is further one of the challenges that hinders understanding the climate variability and its subsequent extreme flood and drought events. Forcing data from different sources, e.g., satellite sensors, in-situ observations, or reanalysis products, are required to derive hydrological models. Reanalysis products have recently become an alternative tool of meteorological data given their long record at various temporal and spatial scales. The overarching goal of this study is to evaluate the primary forcing data for hydrological models; precipitation, as produced by six different reanalysis data (JRA55, 20CRv3, ERA5, ERA-20C, MERRA, NCEP/NCAR). We here focused our evaluation on the major river basins in Africa during a 15-year period spanning from 2001 to 2015. The five major river basins include the Nile River, Congo River, Zambezi River, Orange River, and Niger River basins. Our evaluation method is summarized as follows: Firstly, precipitation data is compared with the gridded gauged data, e.g., CHIRPS for precipitation. Secondly, statistical indices, including categorical and continuous statistical metrics, will be used to assess the accuracy of reanalysis products over each of the major basins. Finally, we present the intercomparison of reanalysis products for extreme events including floods and droughts. The results from our evaluation will pinpoint the skill of reanalysis products and thus benefit the future development of hydrological modeling over the river basins in Africa.
The linkage between active layer thickness, soil moisture and vegetation on James Ross Island, Antarctica
Authors: Hrbáček Filip , Kňažková Michaela , Smolíková Jana
Published: March 2022

Soil moisture is one of the most important parameters of the terrestrial environments in Antarctica. The seasonal amount and availability of liquid water have an essential impact on the abundance and health of the vegetation. Simultaneously, soil water can significantly affect the periglacial environments as its variability can moderate the heat conditions and transport in the active layer and permafrost. It can significantly influence many geomorphological or soil-forming processes. Our contribution evaluates the interactions between surficial soil water content, active layer thickness, and vegetation abundance in the study site on James Ross Island, northern Antarctic Peninsula.

The study area called Berry Hill slope is located in the northern part of James Ross Island. The area is a part of the Circumpolar Active Layer Monitoring – South (CALM-S) network. The study site is about 1 km far from the coastline, about 50 to 60 m a.s.l. In the area, the probing measurements of active layer thickness and surficial volumetric soil moisture in the layer of 0-12 cm were done in February 2018 and 2020. Further, the topography and vegetation extension mapping was carried out using UAV.

The active layer thickness in the CALM-S ranged between 75 and 100 cm. Notably, the lowest values of ALT were detected in the wettest area with an abundance of vegetation. We expect this fact to be caused by both thermal insulations of vegetation carpets and very high soil moisture. The high moisture and almost fully saturated soils prevent active layer thawing propagation due to high latent heat consumption. We found a clear pattern between the abundance of vegetation connected to soil moisture. We observed that the soil moisture threshold allowing vegetation abundance is around 40 %. In contrast, the vegetation misses the rest of the study site, which also has relatively high soil moisture (ca 25-35 % VWC). Considering the warming and drying climate scenario for the region of north-eastern AP, we assume that the active layer will be getting warmer and thicker due to the ongoing climate warming. Active layer deepening might lead to the redistribution of the soil water and the drying of the surficial layers of soil. Consequently, a lack of available soil moisture in the surficial parts can significantly threaten the area's vegetation communities.
PRODUCTION, PURIFICATION AND IMMOBILIZATION OF TRIACYLGLYCEROL LIPASE FROM INDIGENOUS LIPOLYTIC MICROORGANISMS
Authors: Mukhtar Hamid , Khan Madiha , Chaudhary Afia
Published: March 2022

Triacylglycerol lipase was produced from locally isolated Aspergillus niger and Bacillus sp. using submerged fermentation. The process was optimized and lipase was purified and immobilized. Maximum lipase activity was obtained; with microorganisms cultured in medium containing 1% olive oil and 1% soybean meal as substrate, 72hrs incubation at 30Â°C, pH 6.0 and medium supplementation with 2% glucose, 1% peptone for A. niger, 72hrs incubation at 37Â°C, pH 8.0 and medium supplementation with 1% glucose, 1.5% peptone for Bacillus sp. The enzymes were purified using ammonium sulphate precipitation and ion exchange chromatography to achieve 13-14 fold purity with a yield ranging from 53-57%. Lewatite and Amberlite were found to be very good supports for the immoblization of bacterial and fungal lipases, respectively. The immobilization of lipase was proved to be an excellent tool for industrial applications of the enzyme.
A STEADY CASSON FLUID FLOW PAST A STRETCHING POROUS SURFACE IN PRESENCE OF HEAT SOURCE AND CHEMICAL REACTION
Authors: ARDHENDU SEKHAR KHOUND  , DEBASISH DEY  , RUPJYOTI BORAH
Published: March 2022

In this problem a steady Casson fluid flow past an exponentially stretching porous surface is considered with Suction/blowing. Here a uniform magnetic field is applied in the transverse direction to the flow. The governing partial differential equations are reduced to a set of non-linear ordinary differential equations which are further solved numerically with the help of Matlab Build BVP4C technique. Results are discussed with the help of graphs and tables for various values of flow parameters. A special emphasize is given in the effect of Casson fluid parameter on fluid velocity, heat and mass transfer rate of the system.
PERANAN KOMUNIKASI INTERNAL PIMPINAN DALAM MENINGKATKAN KINERJA KARYAWAN DI HOTEL ASHYANA CANDIDASA BEACH RESORT KARANGASEM, BALI
Authors: Murdana I Ketut
Published: March 2022

The research aimed at studying and analyzing the roles of internal management communication in order to increase the staff performances at Ashyana Candidasa Hotel Beach Resort, Karangasem, Bali. The primary research data are directly collected from the management of Ashyana Beach Resort Hotel as a key informan during the structured interview processes and also from the research questionnaires compilation. The informan were using abundant sampling techniques with the total numbers of 25 samples are analysed. The research revealed that 6,25% answered the 13 questions by “YES” which meant that the internal communication has run well meanwhile 5 questions were answered by “YES/NOT” or about 5,25% which meant that internal communication has not yet run well.
PENGARUH CELEBRITY ENDORSER DAN CITRA DESTINASI TERHADAP MINAT BERKUNJUNG WISATAWAN DI DESTINASI WISATA UBUD
Authors: Novta Averina , Liestiandre Hanugerah Kristiono , Aridayanti Dewa Ayu Nyoman
Published: March 2022

One of the efforts to increase interest of visiting is to design a marketing strategy and one of them is an endorser strategy. Endorsers is celebrities or experts who have expertise, awareness and attractiveness, which can represent the image of the product they promote in order to increase visiting interest. Interest of visiting tourists can appear driven by the quality of information provided through promotional strategies carried out by a tourist destination. This research aims to see the influence of celebrity endorsers and destination image on the interest of visiting tourists in Ubud tourist destinations.This research belongs to the type of research with a quantitative approach. The population in this research is millennial domestic tourists who has visited Ubud and sample a total of 200 respondents. The sampling method in this research used purposive sampling with data collection using a questionnaire distributed online with the help of google form and analyzed technique using Structural Equation Modeling (SEM) with SmartPLS 3.0 software. The results of the analysis can be concluded that celebrity endorser and destination image hava a significant influence to visiting intention.