bluuebunny/crossref_metadata_2025 huggingface dataset:
Implications of magnetic secular variation for interpretation of crustal field anomalies
Authors: Saltus Rick , Canciani Aaron , Meyer Brian , Chulliat Arnaud
Published: March 2020

We usually think of crustal magnetic anomalies as static (barring some major seismic or thermal disruption).  But a significant portion of the crustal magnetic field is caused by the interaction of magnetic minerals with the Earth’s magnetic field.  This induced magnetic effect is dependent on the direction and magnitude of the ambient field.  So, of course, as the Earth’s magnetic field changes over time, the form and magnitude of induced magnetic anomalies will vary as well.  These changes will often be negligible for interpretation when compared with measurement and other interpretational uncertainties.  However, with the reduction of various sources of measurement noise and increased fidelity of interpretation, these temporal anomaly changes may need to be considered.

In addition to considerations relating to interpretation uncertainty, these temporal anomaly changes, if they are measured in multiple magnetic epochs, can theoretically provide valuable information for use in source inversion.  For example, since crustal magnetic anomalies arise from a combination of induced (dependent the ambient field) and remanent (not dependent on ambient field) magnetic sources, measurements of secular magnetic variation can assist in separating these two sources during inversion.

We will report modeling of the expected form and magnitude of predicted induced anomaly variations, the possible implications of these variations for data compilation and interpretation, and on the availability of relevant data for measuring them.  Recent research into the use of high-resolution magnetic anomaly maps for airborne magnetic navigation has also brought the issue of changing magnetic fields into focus.  Initial work indicates that changes in induced anomalies could affect navigation accuracy in certain situations.
Neoproterozoic (post-900Ma) cratonization of the Tarim Craton and its role in assembly of the Rodinia supercontinent
Authors: Zhao Pan , He Jinyou
Published: March 2020

In the paleogeographic reconstruction of the Rodinia supercontinent, the Tarim Craton is placed either on the periphery of the supercontinent to the northwestern Australia or in the heart of the supercontinent between Australia and Laurentia. The mystery of the Tarim Craton is caused by the lack of paleomagnetic data, especially during the Rodinia assembly. We present here new primary paleomagnetic data from ca. 900 Ma volcanic strata in the Aksu region of the northeastern Tarim Craton. Rock magnetic investigations reveal magnetite and hematite as the main magnetic carriers. Characteristic remanent magnetizations isolated from 15 sites show both normal and reverse polarities. A site-mean direction is calculated at Dg/Ig = 155.2°/47.5° (kg = 11.6, α95g = 11.7°) in geographic coordinate and Ds/Is = 205.2°/64.0° (ks = 24.4, α95s = 7.9°) after tilt-correction. The site-mean direction passes fold tests and a ~900 Ma paleomagnetic pole is calculated at λ/φ = -0.5°N/62.3°E (A95 = 11.8°) corresponding to a paleolatitude of 45.7° N. The data reveal a ~20° latitude difference between the northern Tarim (N-Tarim) and southern Tarim (S-Tarim) terranes. Together with the late Meso- to early Neo-proterozoic arc magmatism identified both in the central Tarim Basin and along the north margin of the Tarim Craton, a post-900 Ma cratonization of the Tarim Craton resulting from a dual subduction system is proposed. Finally, a new paleogeographic reconstruction of the Rodinia supercontinent is made with the Tarim Craton being placed to the northwestern Australia and cratonization of the Tarim Craton may occur during the Rodinia assembly.
Soil native microbes and multi-species planting for restoring soil function in dryland rehabilitation
Authors: Muñoz-Rojas Miriam , Erickson Todd E. , Bateman Amber , Chilton Angela M. , Merritt David J.
Published: March 2020

Global environmental changes and other anthropogenic impacts are rapidly transforming the structure and functioning of ecosystems worldwide. These changes are leading to soil degradation with an estimated 25 % of the global land surface being affected. The need to develop cost-effective large-scale solutions to restore disturbed landscapes becomes imperative to preserve biodiversity and achieve ecosystem functionality and sustainability. As part of a large-scale industry-academia partnership, we have developed a soil research program that aims to build knowledge and design strategies to restore degraded landscapes in Western Australia and other dryland regions worldwide. Within this program, a series of laboratory experiments, glasshouse studies, and field trials, have been conducted over the past six years to advance our knowledge on soil limitations and to provide solutions to enhance soil carbon levels and restore above and belowground biodiversity in restoration programs. These studies include (i) the analysis of the influence of multi-species planting on soil organic carbon and microbial activity and diversity (ii) the evaluation of soil physicochemical and microbiological indicators to assess functionality of restored soils in degraded semiarid ecosystems and (ii) the development of nature-based strategies based on bio-tools (e.g. inoculation of soil biocrust cyanobacteria) to increase soil carbon and enhance overall soil function. In this presentation we will highlight some key findings of these studies that include the benefits of combining diverse plant species and using native microbes and organic amendments for increasing soil carbon and promote soil function in reconstructed soil substrates. We will also discuss the potential applicability of these bio-technological approaches in landscape-scale restoration programs.
CrowdMag for personal interaction with Arctic magnetic variation
Authors: Saltus Rick , Nair Manoj
Published: March 2020

The Earth’s magnetic field is especially dynamic at high latitudes.  The most awesome manifestation of this is certainly the aurora borealis or northern lights – caused by the interaction of the solar wind with the Earth’s magnetic field.  Aside from the aurora you can’t see these magnetic variations.  But your phone can.  Virtually every modern smartphone is equipped with a 3-component magnetometer to enable the compass pointing capability for navigation.  CrowdMag is a popular NOAA/CIRES citizen science app that we developed to tap into your smartphone’s magnetometer.  It lets you interact with the Earth’s magnetic field.

The purpose of this presentation is to highlight the possibilities for using CrowdMag for science outreach and engagement, particularly in Arctic regions where day-to-day magnetic variations can exceed hundreds of nano-Teslas.  We will show example projects that were carried out by summer interns as part of the University of Colorado’s “Research Experience for Community College Students” (RECCS) program.  CrowdMag can be used to carry out various simple experiments for mapping and investigating the Earth’s magnetic field.  We seek input and collaboration with others interested in Citizen Science and outreach in Arctic regions.   
A statistical learning approach to extract information from hydrologic tracer timeseries
Authors: Harman Ciaran
Published: March 2020

Hydrologic tracer timeseries data (e.g. of stable water isotopes in rainfall and streamflow) have often been analyzed by extracting summary metrics (like the mean transit time) that provide some information about the storage and turnover of water in a watershed, but are laden with ad hoc, implicit, and questionable assumptions. Consequently, inferences about water age and runoff generation processes may be artifacts of the methods, rather than true implications of the tracer data. Potentially more reliable metrics have been suggested recently (e.g. the ‘young water fraction’) but these do not make full use of the information content of the data. The StorAge Selection (SAS) approach relaxes the common (highly questionable) assumption of steady-state flow, and thus allows the full time-variability of the transit time distribution to be captured. However until now its application has required ad hoc functional forms and relationships to be chosen for the underlying SAS function and its time-variability. This introduces artifacts that can skew estimates of the volume and sensitivity of water turnover rates within the catchment, inhibit inference of complex or multi-modal distributions, and is a subjective complication that presents a barrier to use of the approach.

Is it possible to make extract information about catchment water storage, turnover, and transit times without imposing ad-hoc assumptions, and instead allow the data to guide us? Can we obtain a clearer view of how these systems retain and release water of different ages at different rates, and vary how they do so over time? Can doing so allow us to better test hypotheses, tell richer stories about transport in dynamic hydrologic systems? 

Three recent advances toward doing so have recently been developed. The first is to unify the analysis of flux quantity and age (or water celerity and velocity) in the form of an ‘age-ranked storage-discharge relationship’. This relationship captures how the discharge of water of different ages changes when there is a change in the overall discharge. It thus provides a clearer view of the catchment mechanics driving streamflow generation and thus discharge age dynamics.

The second is Multiresolution Estimation of StorAge Selection (MESAS), a non-parametric statistical learning method for determining this relationship. This method avoids the need to specify a functional form – instead the shape of the function is iteratively determined from a coarse to a fine resolution, up to a limit at which the capacity of the data to meaningfully constrain the form is maximized.

The third is the development of computational techniques to accelerate the statistical learning implementation using an explicit Jacobian formulation and GPU acceleration.
Quantifying the role of post-depositional processes on the isotopic composition of surface snow – new findings from the SNOWISO project
Authors: Steen-Larsen Hans Christian , Hörhold Maria , Wahl Sonja , Hughes Abigail , Faber Anne-Katrine , Zuhr Alexandra , Sveinbjørnsdottir Arny , Behrens Melanie , Kipfstuhl Sepp
Published: March 2020

The goal of the SNOWISO project is to quantify the role of the post-depositional processes, which are influencing the isotopic composition of the surface snow and hence the ice core water isotope climate signal. Here we are reporting on findings from field campaigns carried out at EastGRIP over the four summers 2016-2019. We have collected a suite of observations containing the isotopic composition of the surface snow and the snowpack, together with direct observations of atmospheric water vapor isotopes and fluxes between the snow surface and the atmosphere. To support the analysis of the isotopic data we also collected meteorological observations comprising of atmospheric temperature and humidity gradients alongside with sub-surface and snow surface temperature along with atmospheric temperature and humidity gradients. With this dataset we are able to document significant changes in the snow isotopic composition, which are driven by post-depositional processes. The changes in the snow surface isotopic composition is observed to occur on time scales ranging from diurnal to several days. The changes in the snow surface isotopic composition is observed to occur on time scales ranging from diurnal to several days. We can show that the changes in the snow surface is consistent with the flux of the isotopologues between the snow surface and the atmosphere. This gives us confidence that we will be able to develop parameterizations of post-depositional effects, and model their influence on the ice core isotopic climate signal.

 

 
Resilience of the Alsatian aquifer, France to climate and anthropogenic change: A case study of the Grand Ried
Authors: Labarchède Agnès , de Jong Carmen , Giuglaris Élodie , Dumont Serge
Published: March 2020

The vulnerability of the Alsatian aquifer to climate change and water abstraction has hardly been investigated whilst climate change impacts such as decreasing snowfall, droughts and heat waves are becoming stronger and water abstraction for irrigation is seasonally intensifying as a result. Despite being influenced by a European temperate climate, seasonal drying up of groundwater-fed streams has been recently observed in the region of the Grand Ried of the Middle Alsatian Plain and drought decrees in Alsace have intensified. The Alsatian aquifer, an alluvial aquifer located on the French side of the Upper Rhine, belongs to one of the largest aquifers in Europe. It not only provides drinking water to approximately 1.5 million inhabitants but is also a highly important water supply for industry and agriculture. This study aims to improve our understanding of the interactions between groundwater levels of the Alsatian aquifer and river discharge during drought periods. Lying within the Upper Rhine Graben, this complex basin is flanked by the Vosges and Black Forest mountains to the West and East respectively. As such, the aquifer is influenced by both the River Rhine, its main tributaries and the Vosges mountains. At present, it is difficult to differentiate climate and anthropogenic signals in groundwater level lowering during the summer. In this study, spatial and temporal correlations of river discharge and groundwater levels were analysed based on meteorological and hydrological data available since 1955 from national and regional agencies and will form the base for hydrogeological modelling in the next phase. High resolution field data enables to capture complex interactions and for this purpose an intensive interdisciplinary field study was carried out in the summer. Water levels of 7 groundwater-fed streams, including 3 springs, were recorded automatically at hourly time steps and accompanied by manual measurements of temperature, dissolved oxygen and turbidity as well as biological observations. Streams show subdaily water level variations mainly due to evapotranspiration and water withdrawals for irrigation. Even though irrigation represents on average only 18.5% of annual groundwater abstraction in the Alsace region over a territory that is 50% agricultural, water withdrawals are concentrated over a few months in summer and their impacts are visible. Climate change has decreased snow storage and snow water equivalent as well as increased periods without precipitation and thereby increased evapotranspiration over the last decades. The challenge is to determine whether irrigation effects are stronger than evapotranspiration which would imply that water abstraction impact could outweigh that of climate change during summer droughts. Because they can affect the sustainability of drinking water supply, biodiversity and economic activities, awareness on droughts impacts and water abstraction should be increased.
The projected slow-down of mid-latitude temperature anomalies
Authors: Kornhuber Kai , Tamarin-Brodsky Talia
Published: March 2020

The impacts of temperature extremes are strongly amplified with the duration by which they persist over a specific region. In the mid-latitudes, surface-weather as characterized by warm and cold temperature anomalies generally propagates eastward, following the movement of cyclones and anti-cyclones that govern the weather conditions in those regions. It has been suggested that surface weather might become more persistent in the future as a response to changes in land-atmosphere feedbacks and changes to the large-scale circulation, such as a weakening of the zonal winds or a shift in the jet due to the Hadley cell expansion.

In this study, we employ a tracking algorithm to recover the tracks of warm and cold near surface temperature anomalies in comprehensive climate simulations of current and future climates. This enables us to quantify their properties statistically. We focus on their propagation speeds, and find that the eastward movement of both warm and cold temperature anomalies is projected to significantly decrease across the Northern hemisphere mid-latitudes by the end of the century, suggesting an amplified risk of longer lasting hot- and cold extremes under future climate scenarios.

We investigate to what extent this slow-down of mid-latitude temperature anomalies can be attributed to future atmospheric circulation changes on hemispheric and regional levels, and assess how the projected changes in each model are linked to respective trends in high-latitude and land warming.
Numerical Modeling of Non-Newtonian Flows within a Newtonian Equation Framework
Authors: Savant Gaurav , Floyd Ian , Heath Ronald
Published: March 2020

Gravity driven flows such as debris, pyroclastic, avalanche, landslides etc. pose a great threat to life and property. In recent years rainfall combined with prior fire events have resulted in the generation of debris flows in the United States and elsewhere, landslides and mud flows are common occurrences in several regions of  the world where monsoon rains cause soils to saturate, slump and then flow. In some regions these flows take the form of sand, boulders or other cohesionless material generated flows, and avalanches. These flows exhibit non-Newtonian flow characteristics, and provide a challenging engineering problem. These problems arise in the prediction of these flows as well as devising engineering solutions to alleviate danger these pose to the public. Since the advent of numerical modelling, engineers and scientists have used shallow-water equation based mathematical equations to simulate Newtonian flows. In the recent past researchers have attempted to use modifications to the stress terms in the shallow-water equations to account for non-Newtonian behaviour. However these modifications, in general, rely on just one or two of the non-Newtonian formulations to mathematically represent and then numerically simulate non-Newtonian flows. The non-Newtonian behaviour of flows is dynamic, and can change non-Newtonian states depending upon a variety of properties. These properties are inherent to the flows and depend upon the formative process, composition, as well as grain sizes of the debris. Therefore, the requirement is that of a mathematical and numerical description that accounts for these changing states. The Engineer Research and Development Centre (ERDC) of the U.S. Army Corps of Engineers (USACE) has developed a library of debris processes, DebrisLib. This, model agnostic, debris processes library can be linked to any shallow-water based hydrodynamic driver to enable the simulation of debris flows, and the changing non-Newtonian state of the debris flow. This presentation will demonstrate the mathematical development, and incorporation of DebrisLib into the USACE finite element and adaptive meshing software Adaptive Hydraulics (AdH). The implementation will be demonstrated using application to flume tests, avalanches as well as landslides.
Building a historical flooding map through spatial analysis
Authors: Barros Ramalho Alves Priscila , Alexandra Alves Rufino Iana , Djordjévic Slobodan , Javadi Akbar
Published: March 2020

Due to the increase of flooding cases around the world, there is a need for producing even more accurate flood susceptibility mapping. For this, different models, software and frameworks have been developed for many years to assist local authorities and policy-makers for forecasting hazards and mitigating flooding impacts. However, spatially model flooding in real-world systems remains considered as a difficult task. Forecasting flooding requires knowledge from past events and mapping flood locations is crucial to explain the correlation among the flooding and the influencing factors as well as model calibration and validation. In developing countries, a collection of flooding records and inventories remains challenging, either because the data is not available, or because it is not in the suitable scale and resolution. Building historical flooding map is considered a time-consuming process with multiple datasets and normally with costly field surveys. Besides, acquiring this data can be harder due to the inexistence of flooding insurance or civil protection agencies support. This work aims to contribute to this context by developing and assessing a GIS-based framework to map historical flooding cases through the use of spatial analysis. In this study, we used ArcGIS Pro software to construct a historic flooding map for Campina Grande, Brazil. The city faces recurrent flooding episodes, but there is not an available official map with flooding locations to guide decisions for mitigation. The GIS-based framework allows analysing and better understand the interactions of flooding locations and geographic features. The analysis obtained 230 flooding locations in different scales (buildings, streets and neighbourhoods) and sources for the period from 2004 to 2018. Topographic and hydrologic flood influencing factors (altitude, slope, distance to rivers and lakes, flow direction and accumulation) were selected and combined as layers in the GIS environment. Further, criteria were modelled based on spatial analysis and relations to estimate proximity areas around flood occurrence points with high probability of flooding conditions. These tools allowed to compare visual and data patterns of features and surfaces. All locations and factors were then integrated through Model Builder in order to generate a surface with flooding locations within the city. The final historical flooding map was evaluated and validated with 172 points of confirmed flood cases in the city. The GIS-based framework represents a way of analysing and producing historical inventory maps for flooding management using spatial analysis.
The EXCALIBUR project: novel microbial-based bioproducts improving soil biodiversity and the effectiveness of biocontrol and biofertilization practices in horticulture
Authors: Mocali Stefano , Canfora Loredana , Pinzari Flavia , Malusà Eligio
Published: March 2020

The H2020 project Excalibur will be presented. It has the ambition of making the road to a biodiversity-driven change in the soil management of crops through the acknowledgement of the important role of soil biodiversity conservation and exploitation. The project applies integrated approach of research, development and field implementation to achieve its goals. Excalibur will deploy the knowledge gained by new molecular techniques, such as genomic sequences characteristics to specific groups of microorganisms and functions, in the creation of tools, indicators and evaluation systems. Co- innovation is fostered by collaboration of researchers with farmers and manufacturers, with a mutual exchange of information and feedback. Project’s results will bring new insights and practical solutions to stakeholders, validated by process analysis. For this purpose Excalibur plans to: 1) focus on multiscale plant-soil-microbes interactions be to exploit the potential of multifunctional bio-inocula and bio-effectors; 2) optimize the formulation and the application methods of these products based on native soil biodiversity dynamics; 3) develop a strategy to improve the exploitation of soil biodiversity interactions with bio-effectors and bio-inocula by assessing their impacts on crops and biodiversity under contrasting agricultural management practices (conventional, organic) and biotic/abiotic stress conditions; 4) to build a multi-criteria model to assess soil biodiversity status of cropping systems for a more efficient use of bio-effectors and bio-inocula; 5) develop technical tools to monitor the persistence and dispersion of bio-inocula under field conditions for eco-toxicological and agronomical purposes; 6) evaluate the effects of the new strategy on economy, environment quality and ecosystem functions; 7) disseminate results to all stakeholders with a dynamic and comprehensive methodology and encourage the adoption of best practices derived from the new strategy at local, regional and global level.
Multi-method event attribution of 2015 OND drought in subtropical southern Africa
Authors: Fuckar Neven , Otto Friederike , Lehner Flavio , Wolski Piotr , Howard Emma , Sparrow Sarah
Published: March 2020

The subtropical (south of 15deg.S) southern Africa experienced one of the most severe droughts in the record - accompanied with an exceptional heat wave – during the austral spring (October through December – the first half of the main rainy season) of 2015. The observed surface hydro-meteorological conditions led to substantial socio-economic impacts in the region - with mostly semi-arid climate and high spatial-temporal variability - where drought is the principal type of widespread natural disaster. More specifically, very low precipitation - compounded with very high surface air temperature (SAT) - caused low runoff, water shortages and restrictions, reduced electricity generation, and considerable loss of crops and livestock prompting Botswana, Namibia, Lesotho, Malawi, Swaziland and Zimbabwe to declare national drought emergencies. Every extreme event is the result of a combination of external drivers, natural (solar forcing and volcanos), and anthropogenic (carbon dioxide emissions, land use, etc.), and internal variability. The risk-based or probabilistic event attribution assesses to what extent anthropogenic forcing modifies the probability and magnitude, and hence the risk of an extreme event or a class of events to occur (i.e. to identify “the sharp edge” of climate change). This study utilises multiple long-term observations (CRU TS 4.03, GPCC v2018, NOAA PREC/L, etc.), and AGCM and CGCM historical simulations (12 models in total spread across CMIP3, CMIP5 and CMIP6 generations) to estimate risk indicators such as probability (risk) ratio (RR) and intensity change for the OND 2015 drought with respect to the beginning of the 20th century or pre-industrial conditions. Our multi-method approach indicates significant influence of climate change in total OND precipitation, e.g. RR = 1.48 (with 95% CI: 1.20, 1.85), and precipitation-temperature (mean OND SAT) ratio fields over the subtropical southern Africa, but uncertainty of risk indicators can be substantial. The crucial elements of atmospheric circulation and teleconnections (such as Angola Low and ENSO influence) associated with this extreme event are analysed and elaborated using the latest NOAA-CIRES-DOE 20th Century Reanalysis version 3.
Holocene vegetation and climate changes inferred from pollen record of Nordenskiöld Land (West Spitsbergen Island)
Authors: Soloveva Diana , Savelieva Larisa , Verkulich Sergei
Published: March 2020

Pollen analysis is one of the methods that allow revealing ecological and climatic changes in the
past based on vegetation reconstruction. Spitsbergen (Svalbard) archipelago, as well as other
regions of the Arctic, is difficult for creation of regional models of vegetation and climate
development during the Holocene. This is primarily due to the limited distribution, low thickness
and relative young ages (usually this is the late Holocene) of organogenic deposits, which are
most suitable for palynological studies.
Nordenskiöld Land is located in the central part of the West Spitsbergen Island and different the
most favorable climatic conditions. The largest number of sites suitable for paleobotanical
researches is located here. The Coles valley has length about 12 km, well-developed profile and
situated on the north shore of Nordenskiöld Land. The field campaign with studying of
floodplain peat sediments from Coles River valley was carried out in August 2018. Two sites
(K18-15, K18-16) were studied on the remains of first terrace. Excavated deposits are
represented by leafy peat of varying degrees of decomposition with silt lenses. The laboratory
studies of sediments included radiocarbon dating, pollen and non-pollen palynomorph analyses.
They were carried out in Laboratory of St-Petersburg State University and Russian chemical-
analytical Lab on the Spitsbergen archipelago.
The pollen analysis of two sections from Coles River valley allowed us to reconstruct
paleovegetation changes. Samples from K18-15 site contain more mineral components and more
pollen and spores than samples from K18-16 site. This is probably due to the inflow of pollen
with water. The main components of spore-pollen spectra are Poaceae, Cyperaceae, Salix and
Betula sect. Nanae. The relationship between these taxa shows a different degree of moisture of
the study area under the dominance of the grass - sedge tundra. Thus, a significant influence on
the formation of spores and pollen spectra in the studied deposits is played by the dynamics of
the sedimentation.
Results of radiocarbon dating showed that studied deposits formed during mid and late
Holocene.
A generalization of all available palynological data on the Nordenskjöld land made it possible to
construct a scheme of dwarf birch (Betula sect. Nanae) distribution during the Middle and Late
Holocene. A comparison of received data with our previous data and published data from
Nordenskiöld Land shows the asynchronous of appear and distribution of shrubs on these area
from ~5000 to ~2500 yrs ago.
Hierarchical seismic sources model and recent observational evidence
Authors: Ide Satoshi , Aochi Hideo
Published: March 2020

Earthquakes are multiscale phenomena with several scale invariant parameters, such as stress drop, apparent stress, and rupture propagation velocity, and dynamic rupture grows almost self-similarly. While the rupture process is always complex, the location of sources is not completely random, but nearly predetermined, especially along a well-developed fault system like a plate interface. To explain such behavior, some hierarchical structure is required, and one candidate is the hierarchical circular patch (fractal asperity) model suggested by Ide and Aochi (JGR, 2005) and Aochi and Ide (JGR, 2009), in which fracture energy inside a patch is proportional to the patch radius. In this paper, we review the characteristics of the model and show some observational evidence, which has been recently discovered mainly for subduction-type earthquakes in the Tohoku-Oki, Japan, region. Some hierarchical patch-like structure has been identified for several repeating earthquakes of M~5 (Uchida et al., GRL, 2012; Okuda and Ide, EPS, 2018). Identical onsets of seismic waves were observed for many pairs of large (M>4.5) and small (M<4.0) earthquakes (Okuda and Ide, Nature Communications, 2018; Ide, Nature, 2019). We can also observe long-term increase of seismicity before the rupture of system-size events (Okuda et al., Zishin, 2018). These lines of evidence suggest the qualitative validity of the hierarchical model and will be useful to improve the quantitative aspects of the model, such as patch density and the slip-weakening rate, to numerically simulate realistic earthquakes and seismicity (e.g., Aochi and Ide, EPS, 2011; Ide and Aochi, Tectonophysics, 2013; Aochi and Twardzik, Pageoph, 2019).
Dynamic assessment of flood inundation based on a spatiotemporal hydrological model feed by a dynamic representation of human activities
Authors: Aka Kouadio Prudence , Corzo P Gerald A , Yao Koffi blaise 
Published: March 2020

Floods are one of the most recurrent and damaging natural disasters in cities in developing countries today. The city of Abidjan (economic capital of Côte d'Ivoire) is not immune to these disasters. Indeed, according to the ONPC (2014), floods have killed an average of 13 people each year since 2009. One of the causes of the worsening and recurrence of these disasters is the urbanization experienced by the city of Abidjan in recent years. This urbanization has resulted in an increase in waterproofed areas and at the same time an increase in the volume of runoff water. The main objective of this research is to study the dynamics of floods and to see the impact of human activities on the hydrological functioning of the Gourou and Bonoumin watersheds in order to anticipate the risks of flooding. To do this, several specific objectives have been assigned in this study. These are: (1) the morphometric characterization of each watershed ; (2) the cartographic and diagnostic of stormwater management works and the dynamics of land use as well as the study of the variability of rainfall relative to the resurgence of floods in each basin ; (3) the establishment of a geographic information system for the study of floods; and (4) the prospective study of the evolution of land use and the future hydrological functioning of the watersheds studied using scenarios in order to take measures to fight against floods. The equipment used is composed of rain gauges (for measuring the spatial variation of rainfall in each sub-basin), limnimetric scales (to measure the heights of water in rivers), a double-ring infiltrometer (to measure the infiltration capacity on the basins) and software (Goldsim for simulating the behavior of watersheds). The data used consist of climatic data (temperature, rain), historical data on the floods in Abidjan, land use data (satellite images), physical characterization data of the watersheds (slope, hydrographic network, sanitation network , rainwater management works, morphometric parameters of the basins. The methodology adopted consisted of (1) collecting historical data on past floods in Abidjan; (2) description of the environment during rainy events; (3) studying the morphometric parameters of the watersheds studied and also (4) the study of the evolution of rainfall. Thus, the results obtained made it possible to show that the Gourou and Bonoumin basins cover respectively an area of 27.42 km² and 46.37 km² and the Gravelius indices of the two basins are respectively 4.89 and 5.51. Each year, the risk of a flood occurring is 75% with an average of more than 500 million property damage. The level reached in flooded areas of about 1 meter and according to historical data about inundations in Abidjan, on average 16 people lose their lives each year.
Optimal resolution seismic tomography: Lithospheric thinning beneath the British Tertiary Igneous Province and other new observations
Authors: Bonadio Raffaele , Lebedev Sergei , Arroucau Pierre , Schaeffer Andrew , Licciardi Andrea , Agius Matthew , Horan Claor , Collins Louise , O'Reilly Brian , Readman Peter , Working Team the Ireland Array
Published: March 2020

The maximum achievable resolution of a tomographic model varies spatially and depends on the data sampling and errors in the data. Adaptive parameterization schemes match the spatial variations in data sampling but do not address the effects of the errors. The propagation of systematic errors, however, is resistant to data redundancy and results in models dominated by noise if the target resolution is too high. This forces us to look for smoother models and thus limits the imaging resolution.

We develop a surface-wave tomography method that finds optimal lateral resolution at every point by means of error tracking. We first measure inter-station phase-velocities at simultaneously recording station pairs and compute phase-velocity maps at densely, logarithmically spaced periods. Unlike in the classical approach, multiple versions of the maps with varying smoothness constraints are computed, so that the maps range from very rough to very smooth. Phase-velocity curves extracted from the maps at every point can then be inverted for shear-velocity (Vs) profiles. As we show, errors in these phase-velocity curves increase nearly monotonically with the map roughness. Very smooth Vs models computed from very smooth phase-velocity maps will be the most robust, but at a cost of a loss of most structural information. At the other extreme, models that are too rough will be dominated by noise. We define the optimal resolution at a point such that the error of the local phase-velocity curve is below an empirical threshold. The error is estimated by isolating the roughness of the phase-velocity curve that cannot be explained by any Earth structure. A 3D Vs model is then computed by the inversion of the phase-velocity maps with the optimal resolution at every point. The estimated optimal resolution shows smooth lateral variations, confirming the robustness of the procedure. Importantly, optimal resolution does not scale with the density of the data coverage: some of the best-sampled locations require relatively low lateral resolution, probably due to systematic data errors. We apply the method to image the Ireland’s and Britain’s upper mantle, using our large, new regional dataset. We report a pronounced thinning of the lithosphere beneath the British Tertiary Igneous Province, with important implications for the Paleogene uplift and volcanism in the region.
Modelling the deformation and movement of an ice tunnel in Langjökull ice cap, Iceland
Authors: Aðalgeirsdóttir Guðfinna
Published: March 2020

In winter 2014-2015 a long tunnel was dug into the ice cap Langjökull at about 1260 m a.s.l., close to the ELA. The tunnel was opened for tourists in spring 2015 (https://intotheglacier.is/) and has since then become a popular tourist attraction.  Before the tunnel was opened in winter 2015 and in the subsequent two years measurements of the tunnel deformation, temperature and density along the tunnel has been measured.  The tunnel is both closing because of ice deformation and it deforms with the glacier flow, which causes the entrance into the ice tunnel to become gradually steeper.  We use a full-Stokes ice flow model to compute the evolution of the tunnel floor and the closure of the tunnel. The deformation measurements are used to constrain the ice viscosity and the floor measurements to validate the modeled glacier flow. The model simulations are then used to predict the movement of the tunnel in the coming few years, which is useful for the planning of the tunnel entrance renovations.
Electron holes in the Earth's magnetotail current sheet: role of magnetic field gradients and electron anisotropy
Authors: Shustov Pavel , Kuzichev Ilya , Vasko Ivan , Artemyev Anton , Petrukovich Anatoliy
Published: March 2020

Electron holes are nonlinear electrostatic structures that are often observed in the vicinity of the magnetotail energy release regions, e.g. magnetic reconnection. In this work we develop 1.5D Vlasov code simulations of the electron hole dynamics in the magnetic field configuration typical of the current sheet of the Earth's magnetotail. We consider the propagation of electron holes along magnetic field lines in the inhomogeneous magnetic field of the current sheet with realistically anisotropic electron distribution function. We demonstrate that electron holes generated near the equatorial plane of the current sheet brake as they propagate toward the boundaries of the current sheets. This effect is stronger for higher magnetic field gradient and larger electron field-aligned anisotropy. These simulations demonstrate that slow electron holes observed in the plasma sheet boundary layer may appear due to that effect of electron hole braking.
Evaluation of the impact of typhoon initialization on numerical weather forecasts.
Authors: Lim Jeong Ock , Boo Kyung-On , Kong HaeJin , Jun Sanghee , Park Jeong-Hyun , Kang Hyun-Suk
Published: March 2020

   A typhoon is a high-impact weather phenomenon that causes serious damage to people and property when landing on the Korean peninsula. Therefore, accurate prediction of typhoon intensity and track is very important in establishing damage prevention measures. 
   KMA has applied its own typhoon initialization process (KMA bogusing) for Global Data Assimilation and Prediction System (GDPS) to produce realistic initial fields since 2010, when the Unified Model (UM) of UK Met Office (UKMO) was introduced as an operational model. If the typhoon intensity of the background is weaker than the observation, the KMA bogussing process generates horizontally spread mean sea level pressures by using TC warning center’s advisory and use it for data assimilation. 
   In June 2018, GDPS has been upgraded based on PS40 N1280 of UKMO with significantly increased its horizontal resolution from 17 km to 10 km. The new version of GDPS showed improved performance in TC intensity predictions. Since the model simulates tropical cyclone intensity strong enough, we investigated the impact of typhoon initialization on the predictability of the new version GDPS.
When Did Vesicular Av Horizons Form in the Desert SW U.S.: Elucidating Between Soil Processes and Luminescence Ages
Authors: McDonald Eric , Sweeney Mark , Hanson Paul , Sion Brad
Published: March 2020

Vesicular A (Av) horizons, and associated overlying desert (rock) pavement, are ubiquitous features across desert environments.  Extensive research has demonstrated that the Av horizons develop from the incorporation of dust (eolian sediment) during soil development; however, two conflicting models have emerged regarding the age of the Av horizons.  Published luminescence (OSL) ages from Av horizons suggest that Av horizons are Holocene, with reported ages commonly ≤5 ka.  In addition, other studies have suggested Av horizons and desert pavements are Holocene in age because Late Pleistocene environmental conditions (primarily an increase in vegetation cover) largely destroyed desert pavements and Av horizons prior to the Holocene, especially for surfaces above 300-400 m elevation.  In contrast, time-related trends in the morphology of Av horizons suggest that Av horizons and pavements must have existed prior to the Holocene. 

Geochronology and soil morphology from two soil chronosequences formed on alluvial fans in the Mojave Desert (soils ~0.5 ka to ~100 ka, ~900 m above sea level) and in the Sonoran Desert (soils ~0.5 ka to ~250 ka; ~200 m above sea level) indicate that Av horizons existed prior to the Holocene and that the strength of Av development coincides with increasing age of the surface.  In both chronosequences, Av horizon properties of eolian derived silt and clay, development of soil structure, horizon thickness, all systematically increase with surface age on soils with no evidence of past erosion or substantial soil mixing.  Soil morphology and depth profile relations further support that soil profiles are intact with no evidence of erosion or mixing just prior to the Holocene.  OSL dates of Av horizons are considerably younger than soil profiles dated with cosmogenic nuclides and OSL.  Some examples include:  Av: 5ka/soil: 10-12ka; Av: 1-3ka/soil: 16-21ka; Av: 2-6ka/soil: 50-60ka; Av: 1ka/soil: 210 ka.  Mixing of the Av and episodic addition of Holocene dust cannot alone account for age inconsistencies. Recent research using OSL for thermochronology indicates that closure of electron traps occurs between 35o to 50o C.  Measured hourly summer temperatures in Av horizons (Sonoran and Mojave Desert sites) commonly exceed 35 o to 50oC May through September.  We suggest that anomalously young ages for Av horizons may be due to high soil temperatures and degradation of the OSL system.
Interannual to decadal variability in subtropical circulation transport in the south Indian Ocean
Authors: Nagura Motoki
Published: March 2020

This study estimates variability in meridional velocity and transport of the subtropical circulation in the south Indian Ocean using in-situ hydrographic observations, satellite altimetry and two reanalysis products for the period from 2006 to 2017. Previous studies used the zonal difference of satellite sea surface height (SSH) between the western and eastern parts of the basin as an index to variability in basinwide meridional geostrophic transport. This study estimates meridional geostrophic velocity in the upper 1800 m from in-situ observations and compares results with SSH variability. Results show that zonal SSH difference represents a surface trapped variability in meridional velocity, the amplitude of which is large in the upper 250 m and decreases to zero at about 1000 m depth. Zonal SSH difference is significantly correlated with zonally integrated meridional transport relative to 1000 m depth. It is likely that wind variability both in the south Indian Ocean and tropical Pacific Ocean is responsible for this surface trapped variability, as is suggested by past studies. Results of this study also show meridional velocity variability at subsurface, which peaks in magnitude at about 400 to 800 m depth and is not correlated with zonal SSH difference. Waves radiated from the eastern boundary are possibly responsible for the generation of this subsurface flow, but detailed forcing mechanisms are not known in this study. This subsurface flow can contribute to interannual variability in mode water transport and warrants a further study.
The evolution of data and practices within a single mission Science Data Center.
Authors: Larsen Kristopher , Kokkonen Kim , Gehr Adrian , Barnum Julie , Craft James , Pankratz Chris
Published: March 2020

Now entering it’s fifth year of on-orbit operations, the Magnetospheric MultiScale (MMS) Mission has produced over eleven million data files, totaling nearly 180 terabytes (as of early 2020) that are available to the science team and heliophysics community. MMS is a constellation of four identical satellites, each with twenty-five instruments across five distinct instrument teams, examining the interaction of the solar wind with Earth’s magnetic field. Each instrument team developed their data products in compliance with standards set by the mission’s long term data repository, NASA’s Space Physics Data Facility (SPDF). The Science Data Center at the Laboratory for Atmospheric and Space Physics at the University of Colorado is responsible for producing and distributing these data products to both the project’s science team as well as the global scientific community.

                This paper will highlight the challenges the MMS SDC has found with maintaining a data repository during an extended mission, from overall data volumes that preclude providing access to every version of each data product (currently nearing one petabyte for MMS) to adjusting to changing standards and publication requirements. We will also discuss the critical need for cooperation between a mission’s science team, instrument teams, data production, and repositories in order to ensure the data meets the needs of the science community both today and in the future, particularly after the end of a given mission.
Community Built Infrastructure: The Dataverse Project
Authors: Brooke Danny
Published: March 2020

For more than a decade, the Dataverse Project (dataverse.org) has provided an open-source platform used to build data repositories around the world. Core to its success is its hybrid development approach, which pairs a core team based at the Institute for Quantitative Social Science at Harvard University with an empowered, worldwide community contributing code, documentation, and other efforts towards open science. In addition to an overview of the platform and how to join the community, we’ll discuss recent and future efforts towards large data support, geospatial data integrations, sensitive data support, integrations with reproducibility tools, access to computation resources, and many other useful features for researchers, journals, and institutions. 