bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of Arctic and Southern Ocean sea ice between the last nine interglacials and the future
Authors: Wu Zhipeng , Yin Qiuzhen , Guo Zhengtang , Berger André
Published: March 2022

Understanding the sea ice variability and the mechanisms involved during warm periods of the Earth is essential for a better understanding of the sea ice changes at the present and in the future. Based on simulations with the model LOVECLIM, this study investigates the sea ice variations during the last nine interglacials and focuses on the inter-comparison between interglacials as well as their differences from the present and future. Our results show that, for the double CO2 experiment and the Shared Socioeconomic Pathway (SSP)1-2.6, SSP2-4.5 and SSP5-8.5 scenario experiments, the global, Arctic and Southern Ocean sea ice areas simulated by LOVECLIM all fall in the range of the multi-model results from CMIP 6. In addition, the results show that the annual mean Arctic sea ice variation is primarily controlled by local summer insolation, while the annual mean Southern Ocean sea ice variation is more influenced by the CO2 concentration but the effect of local summer insolation can’t be ignored. The lowest Arctic sea ice area results from the highest summer insolation at MIS-15, and the lowest Southern Ocean sea ice area at MIS-9 is explained by the highest CO2 concentration and moderate local summer insolation. As compared to the present, the last nine interglacials all have much less sea ice in the Arctic annually and seasonally due to high summer insolation. They also have much less Arctic sea ice in summer than the double CO2 experiment, which makes to some degree the interglacials possible analogues for the future in terms of the changes of sea ice. However, compared to the double CO2 experiment, the interglacials all have much more sea ice in the Southern Ocean due to their much lower CO2 concentration, which suggests the inappropriateness of considering the interglacials as analogues for the future in the Southern Ocean. Our results suggest that in the search for potential analogues of the present and future climate, the seasonal and regional climate variations should be considered.

Reference: Zhipeng Wu, Qiuzhen Yin, Zhengtang Guo, André Berger, 2022. Comparison of Arctic and Southern Ocean sea ice between the last nine interglacials and the future. Climate Dynamics, accepted.
On the incorporation of transient groundwater conditions resulting from variable flood wave shapes in probabilistic slope stability assessments of dikes 
Authors: van Woerkom Teun , van der Krogt Mark , Bierkens Marc
Published: March 2022

Slope instability of river dikes during floods is often driven by the evolution of groundwater pressures. Despite the temporal nature of high river water levels, pressure heads during floods are often assumed to reflect steady-state seepage conditions, leading to conservative estimates of dike slope safety. Here, we investigate the influence of transient groundwater conditions that result from variable flood wave shapes on probabilistic safety estimates of slope stability. We have sampled a large number of flood waves, aiming to maximize the variability in the flood wave shapes, and used them in a modeling chain consisting of a hydrological model (MODFLOW) and a probabilistic dike slope safety assessment (FORM). We compared the resulting time-dependent probabilistic dike safety for inner (landward) slope and outer (riverward) slope stability with the current flood safety assessment in the Netherlands. This comparison showed that current methods based on steady-state and analytical solutions seem to underestimate dike safety. Other methods, based on a design discharge wave, are more consistent with the multi-flood wave dike reliability, but their error increases at extreme water levels. In line with the temporal component of variable flood water levels, the failure probability also has a strong temporal component. Our results indicate that the highest failure probability always occurs after the river water level peak, with a delay of up to 15 days for both inner slope and outer slope stability. In addition, the uncertainty in the shape of the flood wave can be as important as the uncertainty in the geomechanical material properties for explaining the variation in dike failure probabilities. Therefore, this research strongly suggests that transient-groundwater conditions as a function of variable flood wave shapes should be incorporated in dike safety assessment. As a first step, we recommend further research on the occurrence probability of the most influential waveform characteristics, being the total flood wave volume (for the inner slope) and the total water level decrease after the peak (for the outer slope).
Numerical Modeling of Cascading Foreshocks and Aftershocks in Discrete Fault Network
Authors: Im Kyungjae , Avouac Jean-Philippe
Published: March 2022

Earthquakes often come in clusters formed of foreshock-mainshock-aftershock sequences. This clustering is generally thought to result from a cascading process which is commonly modeled using either the phenomenological ETAS model or a stress-based model assuming an earthquake nucleation process governed by Coulomb stress changes and Rate-and-State friction (CRS). In this work, we numerically investigated the foreshock and aftershock sequence in a discrete fault network with rate and state friction law and compared the result with the ETAS model. We set a fault zone consisting of dense fault segments and an off-fault area consisting of sparsely distributed smaller faults in the simulation domain. The CRS simulations are conducted 100 times with 1000 discrete faults with randomly generated fault location, initial velocity, and fault length within the weighted distribution, yielding a Gutenberg-Richter law. The simulations produce realistic foreshocks and aftershocks sequences. Aftershocks occur in the area of increased Coulomb stress and decay following Omori law as observed in nature. Individual foreshock sequences do not show a clear trend, but once stacked, they show an apparent inverse-Omori law acceleration. The prediction from our CRS model can be fitted with the ETAS model. This is not surprising since ETAS incorporates the Omori and Gutenberg-Richter laws. However, our CRS model predicts significantly more foreshocks than would be expected from the ETAS model. This results from the fact that the triggering productivity is lower in the aftershock sequence than in the foreshocks due to the depletion of critically stressed faults in our simulations. In other words, the ETAS is not compatible with the CRS model because Coulomb stress changes result in a time advance (if positive) or delay (if negative). This clustering process is fundamentally different from the additive process assumed in ETAS. As a result, the claim made that foreshocks more frequent than expected based on ETAS imply pre-seismic slip might be incorrect. It could alternatively be a manifestation of the nucleation process.
Sea wave observing system – initial results
Authors: Palazov Atanas , Ivanov Ivan , Marinova Veselka , Ivanova Veneta
Published: March 2022

Bulgarian National Operational Marine Observing System (NOMOS) is a module of MASRI - Infrastructure for Sustainable Development of Marine Research and Participation in the European Infrastructure Euro-Argo, a project of the National roadmap for scientific Infrastructure (2020 – 2027) of Republic of Bulgaria. NOMOS consist of six components, one of which is a waves and currents monitoring system managed in collaboration by the Institute of Oceanology, Bulgarian Academy of Sciences (IO-BAS) and the National Institute of Meteorology and Hydrology (NIMH). The development of the waves observing system started in 2020 with the deployment of six moored wave buoys, three by IO-BAS and three by NIMH. Next year another three wave buoys were deployed by NIMH. The deployment positions were chosen to provide optimal coverage of the Bulgarian Black Sea coast. The buoy measurements are transmitted using GPRS or satellite communications and are stored in databases both at the Bulgarian National Oceanographic Data Center and at the NIMH data center. WEB sites were developed to deliver real time wave data to stakeholders. The wave observing system has been in operation for over a year and sufficient data has been collected for an initial analysis. During the operation period, experience was gained in maintaining the system in order to provide reliable sea waves data. Biofouling and vandalism are assessed as the main factors influencing system performance. The wave observing system is a unique source of in-situ wave data in the Black Sea that provides real-time wave data and long series of data for science and marine industry.   In-situ wave data are also distributed through CMEMS and used for the assimilation in wave models and quality assessment of forecasts and reanalyzes in Copernicus marine services.
From science to action - climate risk analyses to support adaptation policies and planning at a local level in northern Ghana
Authors: Aschenbrenner Paula , Chemura Abel , Habtemariam Lemlem , Jarawura Francis , Gornott Christoph
Published: March 2022

Agricultural production is highly weather-dependent in sub-Saharan Africa. Under climate change the risk of yield losses increases even further, posing a threat to farmers’ income and livelihood. Despite the availability of a wide range of adaptation strategies for the agricultural sector, information on their suitability at the local scale is limited.

In this session, we would like to discuss an example of a climate risk analysis that supports decision makers on a local scale in northern Ghana in adaptation planning. Using latest past and projected climate data as well as biophysical crop models, the study at first quantified climate impacts on agriculture.  Secondly, the suitability of different adaptation strategies was assessed under socio-economic and biophysical aspects using mixed methods including interviews, literature, a cost-benefit analysis and agricultural modelling. Differential vulnerabilities of farmers based on their identities were taken into account. Relevant stakeholders from Ghanaian local and national governmental institutions, civil society, academia, the private sector, practitioners and development partners were engaged throughout the study process in three workshops, selected the adaptation strategies and were consulted in various interviews.

Results show the dominant negative impacts of climate change on main staple crop yields in northern Ghana with differences according to region, crop and management possibilities of the farmer. The four analysed adaptation strategies (using improved seeds, cashew plantations alley cropped with legumes, Famer Managed Natural Regeneration and Irrigation) can all increase agricultural production and income while having differential positive co-benefits and negative side-effects. Unequal access to power, assets and land leads to differing opportunities in the uptake of suitable measures. Detailed recommendations for an implementation of the adaptation strategies ensuring an increased adaptive capacity of whole communities were developed and discussed with stakeholders. The information was prepared in policy briefs and short films.
The influence of ENSO and Antarctic Oscillation on extreme precipitation over southeastern South America. 
Authors: Hu Xinjia , Decremer Damien , Ferranti Laura , Magnusson Linus , Gong Daoyi , Pappenberger Florian , Kantz Holger
Published: March 2022

The Southeastern South American region (SESA) is one of the AR6 WGI reference regions which is used as an illustration of the interplay between climate variability drivers and regional response. Since most of the agricultural activities take place over this region, its climate variability has a strong impact on society. The region is sensitive to extreme precipitation and puts constraints on water resource management. In recent decades, positive rainfall trends have been detected especially during austral summer. Interactions between the El Nino Southern Oscillation (ENSO) and the Antarctic Oscillation (AAO) also known as the Southern Annual mode, have been well documented indicating the crucial role of ENSO in modulating the AAO phase. In this paper, we explore the interplay between ENSO and AAO and their effect on extreme precipitation over the SESA region during austral spring and summer. Statistical approaches based on extreme value theory (EVT) are applied to daily precipitation amounts to model extreme precipitation, identifying the relative impact of ENSO and AAO. We obtained return values for different phases of ENSO and AAO. We also perform dynamical analysis for sea level pressure and wind field to relate large-scale atmospheric circulation patterns with extreme precipitation.
Weathering, rock type, bedrock incision and landslides in a tropical environment: the Ruzizi gorge in the Kivu Rift, Africa
Authors: Mugaruka Bibentyo Toussaint , Dewitte Olivier , Mugisho Bachinyaga Josué , Mushamalirwa Toussaint , Mees Florias , Nzolang Charles , Dewaele Stijn
Published: March 2022

Tropical environments favour chemical weathering and regolith development. Weathering induces textural, mineralogical and chemical changes in rocks, modifying their strength and thus affecting slope stability. Degree of weathering is, however, not only a function of climatic conditions, but is also influenced by e.g. bedrock composition and structure, exposure length and intensity, and slope angle. To investigate the role of weathering and rock type on landslide occurrence, we focus on the Ruzizi Gorge in the Kivu Rift segment of the western branch of the East African Rift System. Stretching along the border between the DR Congo and Rwanda, development of this 40-km long bedrock river began about 10,000 years ago, rejuvenating the landscape at a very high rate, with rather invariant slope angles outside of the landslides. The gorge stretches across a region where two main types of rocks constitute the geological substrate, i.e. late Miocene to Pleistocene volcanic rocks and Mesoproterozoic metasedimentary rocks. The gorge is a hotspot of deep-seated landsides in the region, with slope failures of up to 2 km². For the present study, we sampled weathering profiles developed on both mentioned rock types, in each case with sampling points within and outside the landslides as well as within and outside the rejuvenated landscape. The chemical composition of rock and regolith samples was determined by Inductively Coupled Plasma–Optical Emission Spectroscopy (ICP–OES) analysis, and their mineralogical composition by X-Ray Diffraction (XRD) analysis and thin section observations. Geotechnical tests were used to determine mechanical properties. Overall, we observe that lithological aspects alone control regolith characteristics, and that slope angle and exposure to landscape rejuvenation hence play no significant role. In areas with volcanic rock substrate, where the largest, mostly slide-type, landslides develop, stratified weathering profiles are observed. These profiles show a greater weathering depth than those over metasedimentary rocks, where flow- and avalanche-type landslides are more common. The regolith derived from volcanic rocks has higher clay content, greater plasticity and stronger cohesion than the sandy to silty weathering material that overlies the metasedimentary rocks. These preliminary results show that weathering and rock type are more important than landscape rejuvenation in controlling the type of deep-seated landslides.
Reconstructing the climate of the Extremadura region (SW Spain) from documentary sources
Authors: Vaquero José M. , Gallego María C. , Bravo-Paredes Nieves , Carrasco Víctor M.S. , Tovar Irene
Published: March 2022

In recent years, our research group has tried to improve the knowledge of the historical climate of the Extremadura region, located in the interior of the southwest of the Iberian Peninsula. Some results can be highlighted:

Temperature and precipitation indices were constructed for the period 1750-1840 from the correspondence of the Duke of Feria (Fernández-Fernández et al., 2014, 2015, 2017).

We have recovered many “pro pluvia” rogation dates (Domínguez-Castro et al., 2021) and we have seen their relationship with the North Atlantic Oscillation (Bravo-Paredes et al., 2020).

We have studied the catastrophic floods of the Guadiana River since AD1500 (Bravo-Paredes et al., 2021).

We have recovered more than 700,000 meteorological data from the Extremadura region taken in the 19th and early 20th centuries (Vaquero et al., 2022), including some uncommon series (Bravo-Paredes et al., 2019).

In recent months, we have started a study of the meteorological information published by the regional press of Extremadura in the last 150 years and here we will present some preliminary results.

References

Bravo-Paredes, N. et al. (2019) Tellus B 71, 1663597.

Bravo-Paredes, N. et al. (2020) Atmosphere 11(3), 282.

Bravo-Paredes, N. et al. (2021) Science of the Total Environment 797, 149141.

Domínguez-Castro, F. et al. (2021) Scientific Data 8, 186.

Fernández-Fernández, M.I. et al. (2014) Climatic Change 126, 107.

Fernández-Fernández, M.I. et al. (2015) Climatic Change 129, 267.

Fernández-Fernández, M.I. et al. (2017) Climatic Change 141, 671.

Vaquero, J.M. et al. (2022) Geoscience Data Journal. https://doi.org/10.1002/gdj3.131
The Jun 15, 2019, M7.2 Kermadec Islands (New Zealand) earthquake as analyzed from ground to space
Authors: De Santis Angelo , Perrone Loredana , Campuzano Saioa A. , Cianchini Gianfranco , D'Arcangelo Serena , Di Mauro Domenico , Marchetti Dedalo , Nardi Adriano , Orlando Martina , Piscini Alessandro , Sabbagh Dario , Soldani Maurizio
Published: March 2022

The M7.2 Kermadec Islands (New Zealand) large earthquake occurred on June 15, 2019 as the result of shallow reverse faulting within the Tonga-Kermadec subduction zone. This work deals with the study of the earthquake-related processes that occurred during the preparation phase of this earthquake. We focused our analyses on seismic (earthquake catalogues), atmospheric (climatological archives) and ionospheric data (from ground to space, mainly satellite) in order to disclose the possible Lithosphere-Atmosphere-Ionosphere Coupling (LAIC). For what concern the ionospheric investigations, we analysed and compared the observations from the Global Navigation Satellite System (GNSS) receiver network and those from satellites in space. Specifically, the data from the European Space Agency (ESA) Swarm satellite constellation and from the China National Space Administration (CNSA, in partnership with Italian Space Agency, ASI) China Seismo-Electromagnetic Satellite (CSES-01) are used in this study. An interesting comparison is made with another subsequent earthquake with comparable magnitude (M7.1) that occurred in Ridgecrest, California (USA) on July 6 of the same year. Both earthquakes showed several multiparametric anomalies that occurred at almost the same times from each earthquake occurrence, evidencing a chain of processes that point to the moment of the corresponding mainshock. In both cases, it is demonstrated that a multiparametric and multilayer analysis is fundamental to better understand the LAIC in complex phenomena such as the earthquakes.
Crustal Structure across Central Scandinavia along the Silver-Road refraction profile
Authors: Kahraman Metin , Thybo Hans , Artemieva Irina , Shulgin Alexey , Hedin Peter , Mjelde Rolf
Published: March 2022

The Baltic Shield is located in the northern part of Europe. It formed by amalgamation of a series of terranes and microcontinents during the Archean to the Paleoproterozoic, followed by significant modification in Neoproterozoic to Paleozoic time by the Sveconorwegian (Grenvillian) and the Caledonian orogenies. The Baltic Shield includes an up to 2500 m high northeast-southwest oriented mountain range, the Scandes, which mainly coincides with the Caledonian and Sveconorwegian deformed parts along the western North Atlantic coast, despite being located far from any active plate boundary.

We present a crustal scale seismic model along the WNW to ESE directed Silver Road profile in northern Scandinavia between 8oE and 20oE. This profile extends south of Lofoten for ~300km across the Norwegian shelf in the Atlantic Ocean and for ~300km across the onshore Caledonides and Baltic Shield proper. The seismic data were acquired with 5 onshore explosive sources and offshore air gun shots from the vessel Hakon Mosby along the whole offshore profile. Data was acquired by 270 onshore stations at nominally 1.5 km distance and 16 ocean bottom seismometers on the shelf, slope and into the oceanic environment. The results of this experiment will provide information on the origin of the anomalous onshore topography and offshore bathymetry at the edge of the North Atlantic Ocean.

We present results from ray tracing modeling and tomographic inversion of the seismic velocity structure along the profile. The crustal structure is uniform with a thickness of 45 km along the whole onshore profile including both the Caledonides and the shield part. The crust thins abruptly to ~25 km thickness towards the shelf around the coastline. Pn velocity is only ~7.6-7.8 km/s below the high topography areas with Caledonian nappes, and extending into the offshore part, whereas it is 8.4 km/s below the shield proper. By gravity modelling we find that the low Pn zone has a low density of 3.20 g/cm3, which we interpret as partially eclogitizised lower crust. The Svecofennian unit has a very high density of 3.48 g/cm3 in the shield with low topography. Isostasy to 60 km depth, as suggested by Receiver Functions, indicates a ~2 km topography which is ~1 km higher than observed. However, recent results from high-resolution seismic tomography shows a velocity change between the two onshore zones down to 120 km depth. Including this observations into the calculations allows us to explain the observed topography by isostasy in the crust and lithospheric mantle.
FastFlood: a fast and simple 2D hydrodynamic or hydrostatic numerical solution to river flow in landscape evolution models
Authors: Steer Philippe , Davy Philippe , Lague Dimitri , Bernard Thomas , Feliciano Hélène
Published: March 2022

Modelling river hydrodynamics in an efficient approach remains a technical challenge which limits our ability to assess river flood hazard or to use process-based erosion laws at a high-resolution in landscape evolution models. Here we present a fast iterative method, entitled FastFlood, to compute river depth and velocity in 2D on a digital elevation model (DEM). This new method solves for the 2D shallow water equation, without the inertia terms, by iteratively building the river water depth using classical flow routing algorithms based on directed acyclic graphs, including the classical single or multi-flow, applied to the water surface. At each iteration, the water depth of each cell of the DEM increases by an increment that is a function of water discharge, computed using a flow accumulation operation, and decreases based on a flow resistance equation, in a manner similar to the Floodos model (Davy et al., 2017). In the hydrostatic mode, this operation is repeated until reaching a near constant water depth over the entire DEM, which occurs after a few tens or hundreds of iterations. FastFlood can also solve for the dynamic propagation of a flood in the hydrodynamic mode. In this case, the water depth increment is only a function of the water discharge exiting the direct upstream neighbors and the iterations are replaced by a time evolution of the water depth. Water depths obtained with the hydrostatic solution were validated against an analytical solution in the case of a rectangular channel and with the Floodos model for natural DEMs. Compared to previous hydrodynamic models, the main benefits of FastFlood are its simplicity of implementation, which mainly requires a classical flow routing algorithm, and its efficiency. Indeed, for a DEM of 106 cells, the algorithm takes about 2 minutes on a laptop to find the hydrostatic solution, about 10 times faster than using the Floodos model (Davy et al., 2017) that was already significantly faster than other hydrodynamic models. Moreover, the computational time scales a little more than linearly with the number of cells, which makes FastFlood a suitable solution even for DEMs larger than 106 – 107 cells. In the future, we expect to make progress on the numerical method by adapting graph-based solutions to the issue of flow water routing. Following Davy et al. (2017), we will also include FastFlood in a landscape evolution model to couple it to process-based laws for erosion, transport and deposition of sediments.
An integrated multi-criteria approach for urban drainage system design considering spatial equity 
Authors: Seyedashraf Omid , Bottacin-Busolin Andrea , Harou Julien J.
Published: March 2022

 The application of optimisation approaches to the spatial design of urban water systems can result in unequal distributions of infrastructure services among different communities unless spatial equity objectives are explicitly considered. Differences between urban communities can be exacerbated if the co-benefits of water infrastructure are not properly distributed over the urban catchment. This is especially important when designing sustainable urban drainage systems, which carry several co-benefits in addition to the attenuation of stormwater runoff,  such as the improvement of urban landscape and mental health of the residents. In this work, we propose a new multi-objective optimisation framework that takes into account both cost-effectiveness and socio-economic aspects of urban drainage infrastructure design. The proposed framework considers the minimisation of capital costs, average flood damages, and total suspended solids as design objectives, as well as the minimisation of inequalities in the spatial distribution of flood damages and green infrastructure benefits quantified via appropriate equity metrics. A population-based multi-objective optimisation method is linked to a hydrologic-hydraulic model to determine a set of Pareto-optimal design portfolios associated with different trade-offs between traditional drainage design objectives and social goals. The proposed multi-criteria design approach was applied to a synthetic case study where sustainable urban drainage systems are used to expand the drainage capacity of an existing pipe network. The results demonstrate the applicability of the proposed methodology to the design of urban drainage systems and provide insights into the trade-offs between overall cost-effectiveness and social equity in urban infrastructure design decisions.
Advancing the Analysis of Volcano-seismic Signals on Etna using Rotational Sensor Data
Authors: Eibl Eva P. S. , Rosskopf Martina , Sciotto Mariangela , Di Grazia Giuseppe , Currenti Gilda , Jousset Philippe , Krüger Frank , Weber Michael
Published: March 2022

Etna volcano in Italy is one of the most active volcanoes in Europe. We recorded the volcanic activity including degassing and vigorous strombolian activity using a seismometer and a rotational sensor in August to September 2019. We test the newly developed rotational sensor in the field in comparison to the broadband seismometer and seismic-network-based locations using the INGV network. We demonstrate that a single rotational sensor co-located with a seismometer can be used to identify specific seismic wave types, to estimate the back azimuth of wave arrivals and the local seismic phase velocities.

Using the rotational sensor, we easily detected the dominant SH-type waves composing volcanic tremor during weak volcanic activity and the recorded VLP/ LP events. Changes in the composition of the tremor wavefield caused by the onset of vigorous volcanic activity are obvious and can be detected in near real-time if data is streamed. We discuss the changes in the wavefield composition from SH-type waves to a mixed wavefield in the context of the volcanic activity, the back azimuth of the signals and associated phase velocities. Our findings are consistent with observations by INGV and hence the rotational sensor reliably enlarges our sensor portfolio in volcanic environments. In fact, wavefield and ground properties can be derived using just one sensor instead of a sensor network, which makes experiments in remote areas cheaper and easier to maintain. In addition, you can observe phenomena that otherwise go unnoticed, like near vent block rotation.
A vast preglacial valley network beneath the Greenland Ice Sheet
Authors: MacGregor Joseph , Chu Winnie , Colgan William , Csathó Beáta , Fahnestock Mark , Felikson Denis , Karlsson Nanna , MacKie Emma , Morlighem Mathieu , Paxman Guy , Tinto Kirsty , Wang Lijing
Published: March 2022

Combining airborne radar-sounding measurements of ice thickness and satellite observations of surface velocity using the principle of mass conservation has revolutionized mapping of subglacial valleys around the periphery of the Greenland Ice Sheet. However, this method cannot presently be applied to the ice sheet’s vast, slow-flowing interior. Instead, ordinary kriging or streamline diffusion are applied to sparser surveys of the interior, despite satellite imagery indicating complex subglacial topography there. This approach aliases that complex topography and limits our ability to interpret the subglacial environment of 75% of the ice sheet. Here we map >1000 prominent lineations in along-flow subaerial surface slope using ArcticDEM. Many lineations are >100 km long and several cross the central ice divide. NASA airborne surveys crossed these lineations thousands of times, and the large majority overlie prominent subglacial valleys, with the remainder overlying ridges. This result is consistent with previous regional studies in both Greenland and Antarctica but its validity is demonstrated here across an entire ice sheet. We explore relations between the geographic distribution of these valleys, their cross-sectional morphology, radar inferences of basal water and theoretical predictions of the transmission of subglacial perturbations to the subaerial ice surface. Our mapping reveals multiple regional networks of dozens of subparallel subglacial valleys of likely preglacial origin, several of which appear to originate from a large but poorly surveyed ice-covered alpine range in eastern Greenland. These patterns indicate that regional geologic fabric is a primary control on subglacial drainage patterns throughout Greenland and they are consistent with the existing hypothesis that the ice sheet’s Pleistocene inception occurred in eastern Greenland. This dataset could be used to validate new methods for mapping subglacial topography that also maintain fidelity to subaerial relief.
Drilling Overdeepened Alpine Valleys (ICDP-DOVE): Age, extent and environmental impact of Alpine glaciations
Authors: Anselmetti Flavio ,   ICDP-DOVE Team
Published: March 2022

The sedimentary infill of glacially overdeepened valleys (i.e. eroded structures below the fluvial base level) are, together with glacial geomorphology, the best-preserved (yet underexplored) direct archives of extents and ages of past glaciations in and around mountain ranges. ICDP project DOVE (Drilling Overdeepened Alpine Valleys) Phase-1 investigates five drill cores from glacially overdeepened structures at several complementing locations along the northern front of the Alps and their foreland. Two of these drill sites, both in the former reaches of the Rhine Glacier, have been successfully drilled in 2021 with excellent core recovery of 95 %: i) The borehole in Basadingen in Northern Switzerland reached a depth of 253 m, and ii) The Tannwald site in Southern Germany consists of one cored borehole to 165 m and two nearby flush boreholes; all three sites will allow a series of crosshole geophysical experiments. Three previously drilled legacy cores from the Eastern Alps are included in the DOVE Phase-1: iii) a core from Schäftlarn, located in the Isar-Loisach glacier catchment, was drilled in 2017 down to a depth of 199 m; iv) the Neusillersdorf drill site, located in the southern German Salzach Foreland glacier area, recovered a sequence down to 136 m (incl. 116 m of Quaternary strata); and v) the drill site Bad Aussee in Austria is located in the area of the Traun Glacier at an inneralpine location. It recovered almost 900 m of Quaternary sediments.

All the sites will be investigated with regard to several aspects of environmental dynamics during the Quaternary, with focus on the glaciation, vegetation, and landscape history. For example, the geometry of overdeepened structures will be investigated using different geophysical approaches (e.g. seismic surveys) to better understand the process of overdeepening. Sedimentological analyses in combination with downhole logging, investigation of biological remains and state-of-the-art geochronological methods will allow to reconstruct the filling and erosion history of the troughs. We expect significant and novel data relating to the extent and timing of the past Alpine glaciations during the Middle-to-Late Quaternary glacial-interglacial cycles. Besides these basic scientific goals, this proposal also addresses a number of applied objectives such as groundwater resources, geothermal energy production, and seismic hazard assessment.

A successful DOVE Phase-1 will lay the ground for an upcoming Phase-2 that will complete the panalpine approach. This follow-up phase will investigate paleoglacier lobes from the western and southern Alpine margins through drilling sites in France, Italy and Slovenia.
A major update to the Exotic Seismic Events Catalog: A compilation of seismogenic mass movements
Authors: Collins Elaine , Allstadt Kate , Groult Charlotte , Hibert Clément , Malet Jean-Philippe , Toney Liam , Bessette-Kirton Erin , Bahavar Manoch , Van Fossen Mick
Published: March 2022

            We present an update to the collection of seismogenic mass movements that forms the basis of the Exotic Seismic Events Catalog (ESEC), doubling the number of events in the catalog from 121 to 242 while broadening the geographic distribution and range of event types. The ESEC is available online through the Incorporated Research Institutions for Seismology (IRIS) Searchable Product Depository (http://ds.iris.edu/spud/esec) or as a downloadable SQLite database from USGS ScienceBase. This update adds more instances of seismogenic landslides, debris flows, snow avalanches, outburst floods, and lahars as well as some new event types: two mine collapses, a submarine landslide, and a volcanic flank collapse. We also now incorporate infrasound detection. Whereas the first version of the catalog focused on mass movements located primarily in the Western United States and Canada, this update includes events from Europe and Pacific Islands. We only include events for which seismic data are openly available.

            We provide both basic seismic information (e.g., station detections on different frequency bands, seismic data location, etc.) and ancillary data such as geometric measurements, references, photographs, and satellite imagery. When available we use published values such as source location, drop height, runout distance, and volume, and when not documented, we estimate values from satellite imagery or photographs. Events are categorized in terms of the quality of the ancillary data, and we provide estimates of uncertainty on parameters such as location and volume. This update increases the availability of seismogenic mass movement data to the community to promote research that betters our understanding of event dynamics and improves methods for exotic event detection, classification, and characterization. Future updates could allow for the incorporation of other exotic event types like blasts and glacial events. The ESEC has a mechanism for community members to contribute events to the collection, so we encourage other researchers to join in the effort.
Magnetic fabric of granite plutons: from anisotropy to processes
Authors: Žák Jiří
Published: March 2022

Since the advent of the anisotropy of magnetic susceptibility (AMS) method, magnetic fabric has become a widely used tool to unravel the internal architecture of granite plutons, with an impressive boom of AMS studies in the 1990s and 2000s. This "boom period" generated a large body of data and led to significant advances in our understanding of how the structural inventory of plutons records magma flow, emplacement, and regional deformation. On top of that, the AMS is capable of revealing an incredible level of detail, especially in combination with mathematical modeling, as to the type, kinematics, and intensity of finite strain. One of the most intriguing discoveries is the key role of AMS in decrypting multiple fabrics that may reflect heterogeneous superposition of intrusive processes by tectonic deformation. Despite a recent decline of interest in the AMS studies, a number of exciting issues still remain to be explored, namely how to use the magnetic anisotropy to interpret the spatio-temporal melt evolution in "fossil" magma chambers and its potential in recording the past motion of lithospheric plates.
Paleomagnetism of the Glen Mountains Layered Complex: Dipolar field behavior at ~530 Ma
Authors: Kodama Kenneth , Tetto Frank , Tarduno John
Published: March 2022

Results from the Sept-Îles intrusive suite suggest that the Earth’s magnetic field reached ultra-low intensities at 565 Ma (~3 μT, Bono et al., 2019) during the Ediacaran Period. Additional evidence from this study suggests abnormally high paleosecular variation (S= ~26˚). Other studies of Ediacaran rocks indicate very high reversal frequencies. Based on this abnormal geomagnetic field behavior, Bono et al. (2019) suggested inner core nucleation at about 565 Ma. Therefore, we conducted a detailed paleomagnetic study of the early Cambrian (206Pb/238U age of 532.49±0.12 Ma, Wall et al., 2020) Glen Mountains Layered Complex (GMLC) of southwestern Oklahoma to assess behavior of the geomagnetic field 30 myr later. One hundred ninety independently oriented cores were drilled from 17 sites collected from the anorthosites of the GMLC. Primary paleomagnetic directions were isolated by thermal and alternating field demagnetization. Magnetic susceptibility versus temperature and isothermal remanence acquisition experiments both indicate that low-Ti magnetite is the dominant remanence carrier, although minor pyrrhotite is seen in some samples. Nearly antipodal directions, collected from different sites, pass a simple reversals test, confirming that geomagnetic field polarity reversals are recorded (Roggenthen et al., 1981) and that the GMLC anorthosites carry a primary remanence. Paleosecular variation recorded by the GMLC (S=10.9˚) for a paleolatitude of 10.3˚ is in agreement with Smirnov et al.’s (2011) tabulation of paleosecular variation for 1.0-2.2 Ga intrusive and extrusive igneous rocks. A reversed polarity paleopole for the complex is located at 26.1°E, 25.3 °N (A95 = 7.4°). Our results suggest that the geomagnetic field returned to stable, dipole-dominated behavior by about 530 Ma.

Bono, et al. (2019). Nature Geoscience, 12(2), 143-147.

Smirnov, et al. (2011). PEPI, 187(3-4), 225-231.

Roggenthen et al., (1981) GRL, 8, 133-136.

Wall et al. 2020, Geology, 49, 268-272.
Intensified continental chemical weathering and carbon-cycle perturbations linked to volcanism during the Triassic–Jurassic transition
Authors: shen jun
Published: March 2022

Direct evidence of intense chemical weathering induced by volcanism is rare in sedimentary successions. Here, we undertake a multiproxy analysis (including organic carbon isotopes, mercury (Hg) concentrations and isotopes, chemical index of alteration (CIA), and clay minerals) of two well-dated Triassic–Jurassic (T–J) boundary sections representing high- and low/middle-paleolatitude sites. Both sections show increasing CIA in association with Hg peaks near the T–J boundary. We interpret these results as reflecting volcanism-induced intensification of continental chemical weathering, which is also supported by negative mass-independent fractionation (MIF) of odd Hg isotopes. The interval of enhanced chemical weathering persisted for ~2 million years, which is consistent with carbon-cycle model results of the time needed to drawdown excess atmospheric CO2 following a carbon release event. Lastly, these data also demonstrate that high-latitude continental settings are more sensitive than low/middle-latitude sites to shifts in weathering intensity during climatic warming events. 
Exploring potential impacts of Black Carbon on vertical mixing and overall air quality over Northern India
Authors: Agarwal Prerita , S. Stevenson David , R Heal Mathew
Published: March 2022

Black Carbon (BC) particles from incomplete combustion perturb the Earth's energy balance by absorbing solar radiation and modifying cloud microphysics. Previous studies have shown that Indian BC emissions significantly impact the summer monsoon, regional climate, and human health. Studies over China have reported that high BC concentrations absorb sufficient radiation to influence planetary boundary layer (PBL) vertical stability and mixing, and can significantly affect overall near-surface air quality. Such effects may have important implications for mitigation efforts that aim to improve regional air quality and climate. Here, we explore BC during extreme pollution events over India, using the WRF-Chem Chemistry Transport Model v4.2 with the MOSAIC sectional aerosol scheme at a horizontal resolution of 12 km × 12 km. The model is able to capture elevated PM2.5 concentrations (~300 μg m-3) over the Indo-Gangetic Plain and localised hotspots over some major megacities. To isolate contributions of emissions from anthropogenic and biomass burning sources to the overall air quality, we perform a base simulation and sensitivity experiments. We analyse the diurnal evolution of vertical profiles of BC and PM2.5 in the PBL. We focus on the factors that control these distributions and compare our results with available observations to evaluate the model. Diurnal PBL dynamics strongly influence temporal and spatial variations in aerosol concentrations. We investigate the role of BC in influencing the PBL dynamics during high pollution events, and hence overall air quality by perturbing the vertical radiation, temperature, and stability profiles.
Secular change in the age of TTG sources during the Archean from in-situ Sr and Hf isotope analysis by LA-MC-ICPMS
Authors: Musiyachenko Kira , Smit Matthijs , Caton Summer , B. Emo Robert , Kielman-Schmitt Melanie , Kooijman Ellen , Scherstén Anders , Halla Jaana , Bleeker Wouter , Hoffmann J. Elis , Prakash Pandey Om , Ravindran Arathy , Maltese Alessandro , Mezger Klaus
Published: March 2022

Much of the continental lithosphere developed during the Archean, which was an Eon of change in terms of global geodynamics and geochemical cycles. Uncovering the causal links between crust forming processes and prevailing geodynamic mechanisms is crucial for understanding the origins and composition of the present-day continental lithosphere. Pristine Archean crust is scarce yet can be found in cratons worldwide. Many of these occurrences comprise rocks of the tonalite-trondhjemite-granodiorite (TTG) suite, which represent a prevalent component of the Archean continental crust. TTGs are generally considered to have formed by partial melting of amphibolite or eclogite source rocks that had basaltic precursors originally extracted from a depleted mantle (e.g., [1]). The age of the source rocks (i.e., the time between the basalt extraction from the mantle and TTG formation) can be determined from the initial radiogenic isotope compositions of TTGs, provided that the P/D ratio of the source can be reliably estimated and is significantly different from that of the depleted mantle.

Based on this principle, we estimated the age of basaltic sources of TTGs from cratons of different age and paleogeography from initial 87Sr/86Sr compositions determined by in-situ Sr isotope analysis of primary igneous apatite (LA-MC-ICPMS). The 87Sr/86Sr of these apatites show that prior to 3.4 Ga TTGs were derived from relatively old mafic sources and that the average time between formation of basaltic material from the mantle and subsequent remelting under amphibolite to eclogite facies conditions decreased drastically during the Paleoarchean. This secular change indicates a rapid global increase in the efficiency of TTG production or the emergence of a new TTG-forming process at c. 3.4 Ga [2].

In this contribution we explore this hypothesis by comparing the 87Sr/86Sr signature of the TTGs with their trace-element compositions, as well as with 176Hf/177Hf zircon data for these rocks and contemporary TTGs from other studies. This combined geochronological, isotope and geochemical analyses will provide new constraints on the age of TTG sources during the Archean and will allow investigation into the nature and probable causes of the apparent rejuvenation at 3.4 Ga, as indicated by Sr isotopes.

[1] Hoffmann, J.E. et al. (2011) Geochim. Cosmochim. Acta 75, 4157-4178.

[2] Caton, S., et al., (in review) Chem. Geol.
Terrestrial biomarkers in sediments from the continental slope of Nordaustlandet, Svalbard reveal unprecedented subglacial meltwater drainage during the Last Termination
Authors: Nogarotto Alessio , Noormets Riko , Chauhan Teena , Colleoni Florence , Mollenhauer Gesine , Muschitiello Francesco , Capotondi Lucilla , Pellegrini Claudio , Belt Simon , Tesi Tommaso
Published: March 2022

The subglacial environment and its characteristics are of primary importance for the behaviour and the stability of ice sheets; however, the mechanisms that take place beneath ice sheets still need to be accurately quantified. Here we present the results of a multi-proxy, biogeochemical analysis carried out on a marine sediment core (HH11-09GC) from the northern Svalbard continental slope, encompassing the last 30 ka. During Termination I, our results suggest a persistent polynya-like environment with significant input of terrigenous organic matter. Indeed, the amount of land-derived material during this period is comparable to that found in the immediate proximity of the major Siberian river mouths during modern times. Alkenone fingerprint suggests that the origin of the terrigenous material could be related to an as yet unidentified freshwater body located in the White Sea/Pechora Basin region, at the margin of the Svalbard Barents Sea Ice Sheet; therefore, the environmental conditions at the base of the ice sheet were suitable for the existence of a large subglacial water drainage. According to our data, this drainage network was able to carry huge amounts of water and sediments beneath the ice sheet and, subsequently, discharge them thousands of kilometres away from their origin. This could represent the first evidence of a pervasive, highly connected subglacial drainage network in the Barents Sea region. Our results may shed new insights on the magnitude of subglacial drainage systems, and thus have important implications with regards to ice sheet modelling.