bluuebunny/crossref_metadata_2025 huggingface dataset:
Case study of an Arctic atmospheric river with the ICON model
Authors: Bresson Hélène , Rinke Annette , Schemann Vera , Mech Mario , Crewell Susanne , Viceto Carolina , Gorodetskaya Irina , Ebell Kerstin
Published: March 2021

The Arctic climate changes faster than the ones of other regions, but the relative role of the individual feedback mechanisms contributing to Arctic amplification is still unclear. Atmospheric Rivers (ARs) are narrow and transient river-style moisture flows from the sub-polar regions. The integrated water vapour transport associated with ARs can explain up to 70% of the precipitation variance north of 70°N. However, there are still uncertainties regarding the specific role and the impact of ARs on the Arctic climate variability. For the first time, the high-resolution ICON modelling framework is used over the Arctic region. Pan Arctic simulations (from 13 km down to ca. 6 and 3 km) are performed to investigate processes related with anomalous moisture transport into the Arctic. Based on a case study over the Nordic Seas, the representation of the atmospheric circulation and the spatio-temporal structure of water vapor, temperature and precipitation within the limited-area mode (LAM) of the ICON model is assessed, and compared with reanalysis and in-situ datasets. Preliminary results show that the moisture intrusion is relatively well represented in the ICON-LAM simulations. The study also shows added value in increasing the model horizontal resolution on the AR representation.
High-frequency river chemistry unveils the inner workings of concentration-discharge relationships during flood events
Authors: Floury Paul , Bouchez Julien , Gaillardet Jérôme , Blanchouin Arnaud , Ansart Patrick
Published: March 2021

Shifts in water fluxes through the Critical Zone exert a major control on stream solute export, but the exact nature of this control is still obscure, especially at the scale of relatively short flood events. To address this question, here we take advantage of a new high-frequency, flood event stream concentration–discharge (C-Q) dataset. Stream dissolved concentration of major species were recorded every 40 minutes over five major flood events in 2015/2016 recorded in a French agricultural watershed using device called the "River Lab". We focus our attention on the flood recession periods to highlight how C-Q relationships are controlled by hydrological processes within the catchment rather than by the dynamics of the rain event.

We show that for C-Q relationships resulting from data acquisition over multi-year time scales and including several flood events, lumping all trends together potentially result in biases in characteristic parameters (such as exponents of a power-law fit), that are strongly dictated by data from the recession periods of the most intense floods alone.

In order to evaluate the role of mixing of pre-existing water and solute pools in the catchment, we apply to solute fluxes an approach previously developed in catchment hydrology linking water storage and stream flow. This approach, which considers that hydrological processes prevail over chemical interactions during the short time spans of flood events, allows us to reproduce at first order a large diversity of shapes of recession C-Q relationships.
Investigating magnetopause dynamics using global magnetosphere simulation 
Authors: Brenner Austin , Pulkkinen Tuija
Published: March 2021

Detailed 3D magnetopause surface is identified using field line and flow line tracing techniques on Space Weather Modeling Framework (SWMF) global magnetosphere simulation results. A total energy flux vector dominated by poynting flux is dotted with area element surface normals and integrated to determine energy transfer into the closed volume. Magnetopause characteristics, power and energy terms are compared with space weather indices such as Disturbance Storm-Time (Dst), Auroral Electrojet (AE), Cross Polar Cap Potential (CPCP) and emperical models such as Shue et al (1997) and Shue et al (1998) to investigate magnetopause dynamics. The storm event of Feb 18, 2014  is simulated with SWMF and analyzed. This event starts in the middle of a multi-CME impact, during a delay between the first and second CME's. While some preconditioning may have occured, it provides an excellent case for observing magnetopause variations. Results show close agreement with empirical models of integrated energy transfer through magnetopause surface. Energy accumulation inside magnetopause volume cuttoff at x=-20Re shows similar behavior to Dst.
Developing multiscale terrain signatures for seabed classification
Authors: Lecours Vincent
Published: March 2021

It is increasingly recognized that environmental variables must be considered at multiple spatial scales to produce maps of the seabed that better capture and represent geomorphic features and marine habitats. In this paper, the ability of new multiscale geomorphometric variables to classify different types of seabed habitats is tested. A digital terrain model of an area of coastal Florida with different types of intertidal habitats was used in the geospatial data analysis platform Whitebox Tools to generate multiscale measures of roughness, maximum deviation from mean elevation, maximum anisotropy in elevation deviation, maximum difference from mean elevation, and maximum spherical standard deviation. Results show that oyster reefs, muddy areas, and areas with aquatic vegetation have different multiscale terrain signatures, highlighting the potential of multiscale terrain attributes to inform seabed classification.
Communicating in the aftermath of an earthquake: when Twitter proves to be a trustworthy and empathetic information channel.
Authors: Corradini Marina , Fallou Laure , Bossu Rémy , Roussel Frédéric
Published: March 2021

Twitter has proved to be a powerful tool for the dissemination of scientific information in the aftermath of a seismic event. During an earthquake crisis, the affected population is in need of rapid, reliable information on what has just happened and what to do next to stay safe. However, it is not rare that reliable earthquake information takes a few minutes to be accessible and shared with the population. This shortcoming can have harmful impact: every time there is a lack of information, rumors fill the void and misinformation spreads. To make matters worse, scientific communication is often jargon-laden and hence perceived as overly technical, inappropriate, and unfeeling. Effective earthquake communication must therefore be:

rapid and clear, to prevent fake news from spreading;

transparent, by acknowledging uncertainty if reliable information is not available yet;

empathetic and compassionate, to decrease anxiety and promote a sense of calming.

In this light, we discuss the communication strategy of @LastQuake, the official Twitter channel (160k followers) of the Euro-Med Seismological Centre. When an earthquake strikes and is felt by the population, real-time information on the seismic event begins to be automatically published via a twitter-robot. These automatic tweets range from easily-accessible scientific information about the earthquake location and magnitude, to the shaking felt by the earthquake eyewitnesses, to the safety guidelines and –where applicable– to tsunami warnings. Our automatic tweets have little or no technical jargon. The Information is primarily accessed by users who are in the midst of responding and possibly traumatized. Hence our words, tone, and images have been carefully chosen to provide competent and appropriate communication. Meanwhile, when necessary, further tweets may be manually published to counter the onset of specific false claims and theories, or to address cultural and situational specific needs.  

Our discussion will outline the current @lastquake twitter-bot environment and discuss evidence-based best practices for using Twitter for earthquake crisis communication to avoid misinformation and promote self and community efficacy.
Experiment and simulation of stress-dependent P-wave velocity anisotropy in sandstone
Authors: Shen Haimeng , Li Xiaying , Li Qi
Published: March 2021

Velocity anisotropy is particularly important in field applications of seismic monitoring or exploration [1]. We investigate the stress-dependent P-wave velocity anisotropy of sandstones with triaxial experiments and PFC based numerical simulation [2-3]. The sandstone sample was taken from the lower Shaximiao formation, Sichuan Basin, China [4]. The evolution of anisotropy is discussed with the ellipse least-squares fitting method. The results show that the P-wave velocity is affected by both the bedding plane and loading conditions. As confining pressure increases, the anisotropy magnitude decreases for each sample. The direction of anisotropy is along with the direction of the bedding plane. Under deviator loading, the anisotropy is strengthened for the sample with bedding parallel to the maximum principal stress. The direction of anisotropy reversal occurs in the sample with bedding normal to the maximum principal stress. And the anisotropy magnitude of that sample is reduced firstly and then improved. The P-wave velocity anisotropy is originated from preferred mineral orientation and aligned cracks in these samples. The stress has little effect on the mineral orientation. The evolution of P-wave velocity anisotropy is related to closing and reopening of microcracks.

 

Keywords: Velocity anisotropy; Anisotropy reversal; Triaxial experiment; PFC2D; Sandstone

 

[1] Li, X., Lei, X. & Li, Q. 2018. Response of Velocity Anisotropy of Shale Under Isotropic and Anisotropic Stress Fields. Rock Mechanics and Rock Engineering, 51, 695-711, http://doi.org/10.1007/s00603-017-1356-2

[2] Li, X., Lei, X. & Li, Q. 2016. Injection-induced fracturing process in a tight sandstone under different saturation conditions. Environmental Earth Sciences, 75, 1466, http://doi.org/10.1007/s12665-016-6265-2

[3] Shen, H., Li, X., Li, Q. & Wang, H. 2020. A method to model the effect of pre-existing cracks on P-wave velocity in rocks. Journal of Rock Mechanics and Geotechnical Engineering, 12, 493-506, http://doi.org/10.1016/j.jrmge.2019.10.001

[4] Li, X., Lei, X., Li, Q. & Chen, D. 2021. Influence of bedding structure on stress-induced elastic wave anisotropy in tight sandstones. Journal of Rock Mechanics and Geotechnical Engineering, -, http://doi.org/10.1016/j.jrmge.2020.06.003
Direct Observational Evidence of the Simultaneous Excitation of Electromagnetic Ion Cyclotron Waves and Magnetosonic Waves by an Anisotropic Proton Ring Distribution
Authors: Teng Shangchun , Liu Nigang , Ma Qianli , Tao Xin , Li Wen
Published: March 2021

Magnetosonic (MS) waves and electromagnetic ion cyclotron (EMIC) waves are two important plasma wave modes in the magnetosphere. Previous simulations have shown that both waves could be generated by a ring-like proton distribution, while direct observational evidence has yet to be reported. Here, we present simultaneous observations of MS and EMIC waves and a detailed case analysis. The linear growth rates estimated for both waves are in good agreement with the observed wave frequency spectra. The measured proton distribution evolution is also compared with the simulation results, providing direct observational evidence for the previous theoretical prediction that anisotropic ring-like proton distributions could excite MS and EMIC waves simultaneously. Our findings are crucial for understanding the generation mechanisms of and relation between MS and EMIC waves and for evaluating their combined effects on energetic electron and ion dynamics. 
Does a stability constant decide on a repository permit?
Authors: Hennig Theresa , Kühn Michael
Published: March 2021

Safety of a nuclear waste repository is based to a large extent on the isolation of the radioactive waste within a suitable host rock. Clay rocks provide an option due to their very low hydraulic conductivity only allowing diffusive transport. Diffusion processes in clay formations are complex due to the diffuse double layers (DDL) enveloping the clay minerals to compensate their net surface charge and the associated different migration behaviour for cationic, anionic and neutral species. Therefore, determination of the speciation of an element in the porewater is essential to quantify migration lengths precisely. Safety assessments are based on numerical simulations to cover time periods of up to one million years and thus the predominant species of a radionuclide, dependent on the stability constants within the law of mass action, might be signififcant.

In the present study, we use uranium, one of the main components in spent fuel, as an example for the diffusion in the Swiss Opalinus Clay, a potential host rock for the storage of nuclear waste. In the geochemical system, uranium is mainly present as U(VI) in ternary uranyl complexes with calcium and carbonate, whereby speciation depends on the selected thermodynamic data (Hennig et al., 2020). For instance, the stability constants for the neutral uranyl complex Ca2UO2(CO3)3 differ slightly in literature. Depending on the selected one, either the neutral or the anionic complex CaUO2(CO3)32- is the predominant species in the system with an associated varying interaction with the DDL of the clay minerals. With our one-dimensional, multi-component diffusion models we quantified the effect of the selected stability constant on the diffusion length for the host rock scale.

The chemistry in the porewater of the three facies of the Opalinus Clay, shaly, sandy and carbonate-rich, plays a key role for the sorption processes (Hennig et al., 2020) as well as for the composition and thickness of the DDL and therewith the diffusive transport. Based on our results, we show, that the influence of the predominant uranium species on the migration lengths varies between the individual facies, but is overall negligible for the host rock scale. Consequently, a stability constant is not decisive for the required thickness of the host rock as geological barrier.

 

Hennig, T.; Stockmann, M.; Kühn, M. Simulation of diffusive uranium transport and sorption processes in the Opalinus Clay. Applied Geochemistry 2020, 123. doi:10.1016/j.apgeochem.2020.104777.
Recurrent Rossby wave packets and persistent extreme weather
Authors: Ali S. Mubashshir , Martius Olivia , Röthlisberger Matthias
Published: March 2021

Upper-level synoptic-scale Rossby wave packets are well-known to affect surface weather. When these Rossby wave packets occur repeatedly in the same phase at a specific location, they can result in persistent hot, cold, dry, and wet conditions. The repeated and in-phase occurrence of Rossby wave packets is termed as recurrent synoptic-scale Rossby wave packets (RRWPs). RRWPs result from multiple transient synoptic-scale wave packets amplifying in the same geographical region over several weeks.

Our climatological analyses using reanalysis data have shown that RRWPs can significantly modulate the persistence of hot, cold, dry, and wet spells in several regions in the Northern and the Southern Hemisphere.  RRWPs can both shorten or extend hot, cold, and dry spell durations. The spatial patterns of statistically significant links between RRWPs and spell durations are distinct for the type of the spell (hot, cold, dry, or wet) and the season (MJJASO or NDJFMA). In the Northern Hemisphere, the spatial patterns where RRWPs either extend or shorten the spell durations are wave-like. In the Southern Hemisphere, the spatial patterns are either wave-like (hot and cold spells) or latitudinally banded (dry and wet spells).

Furthermore, we explore the atmospheric drivers behind RRWP events. This includes both the background flow and potential wave-triggers such as the Madden Julian Oscillation or blocking. For 100 events of intense Rossby wave recurrence in the Atlantic, the background flow, the intensity of tropical convection, and the occurrence of blocking are studied using flow composites.
The Main Ethiopian Rift: Ongoing deformation inferred from earthquake mechanism
Authors: Muluneh Ameha
Published: March 2021

The northern Main Ethiopian Rift (MER), which forms the northern part of the East African Rift System, offers an excellent tectonic setting to study the transition from continental to oceanic crust and also from tectonic to magmatic rifting. Opening of the rift started at 11 Myr ago. Until about 7 Ma, deformation was mainly accommodated at the rift border faults. Between 7 and 3 Ma, deformation migrated from the border faults to 20-30 km wide, 60 km long  magmatic segments. Earlier geodetic and field geological observations suggest that more than 80% of the present day opening of the rift is accommodated beneath these magmatic segments. On the contrary, recent observations indicate that deformation is more widespread than previously thought, with only 40% of the present day deformation being accommodated at the rift centre. 

 

Detailed understanding on the depth and epicentral distribution of earthquakes provides an important constraint on how strain is partitioned between the rift floor and border faults. Here I use high resolution earthquake catalogue and thermo-rheological modeling to constrain the active deformation patterns in the northern MER by assuming that the long term properties of the lithosphere represent the short term earthquake cycle. The final result of this study has significant implications for the location and magnitude of seismic hazard in the rift. 
Climate Change Impacts on a Mediterranean Coastal Wetland due to Sea Level Rise (L’Albufera de Valencia, Spain)
Authors: Estrela Segrelles Clara E , Pérez Martín Miguel Ángel , Gómez Martínez Gabriel
Published: March 2021

Sea level rise produced by climate change severely affects coastal ecosystems. The increase in the area below sea level facilitates the penetration of the marine wedge and causes an increase in soil salinity. Coastal wetlands are areas of great ecological importance due to the richness of flora and fauna that inhabit them. A change in salinity conditions could lead to a reduction or loss of habitat for the wetland biota. Based on RCP4.5 and RCP8.5 CMIP5 multimodel scenarios, in the Western Mediterranean coast, the sea level will rise 0.16 m in the short term (2026 - 2045) and 0.79 m in 2100. Also, high-end scenarios indicate that sea level will rise between 1.35 m and 1.92 m in the long term.

A sea level rise analysis has been developed in the coastal wetlands of Júcar River Basin District (JRBD). The results show that coastal wetlands are the mainly area affected in the JRBD, so the 90% of the area under the sea level are wetlands. L’Albufera de Valencia is the main wetland in this basin and, also the main wetland affected. It is an anthropized humid zone, regulated by users through gates to preserve the adequate water level for agricultural and environmental purposes such as rice cultivation around the lake and bird habitats conservation, especially in winter. The outcome of the study shows a significative increase in the area below the sea from 507 ha and 4.2 hm3 of water volume at present to 3,244 ha that represents 42.6 hm3 of water volume in the short term. In the long term, the area below the sea is 7,253 ha which means 118.4 hm3 of water volume in the percentile 50 scenario and, in the worst extreme scenario, it is 13,896 ha that represents 289.7 hm3 of water volume. This leads to a redefinition of the lake management levels as a climate change adaptation measure to prevent the lake salinization and severe impacts in the lake ecosystem. L’Albufera lake levels need to be increased in the next years to avoid the sea water penetration, related to the sea level rise. Thus, in the short term the lake levels must be increased around 0.16 m and, in the long term, L’Albufera levels must be increased around 0.8 m.
 Wind-induced waves and storms in fan-delta lacustrine successions: New observations from Tanan Depression, Tamtsag Basin, Mongolia
Authors: Xinyu Xue , Zaixing Jiang , Li Wang
Published: March 2021

Existing fan-delta depositional models for lacustrine basins do not adequately address significant wave- and storm-related processes. However, in many lakes, such high-energy processes can be effectively driven by winds. As such, the prevailing wind direction determines the progradation direction of wind-induced waves. Observations from modern cases show that wave-dominated deposits commonly exist on one side of the lake, and their sedimentary processes are completely distinct from those on the opposite side, such as in Qinghai Lake in China. However, equivalent deposits have seldom been identified from subsurface data. We present an ancient example from the Upper Tongbomiao Formation in the Tanan Depression (Tamtsag Basin, Mongolia), which was previously interpreted as a fan-delta depositional system. Based on extensive core investigations, eighteen lithofacies, six lithofacies associations and two genetic deposition systems are identified, and a new sedimentological interpretation is proposed for the Upper Tongbomiao Formation containing a wave-dominated clastic shoreline system in the western half-graben dip slope (W-DS) and a fluvial-dominated fan-delta system in the eastern half-graben (E-HG). Sediments within the E-HG unit are grouped into the three lithofacies associations of braidplain, fan-delta front and prodelta, while those within the W-DS unit comprise dominantly alluvial fan, wave-reworked beach, storm-affected shoreface and offshore sediments. Several factors contribute to the preservation of these two distinct sedimentary systems that developed on opposite shores of the lake: (i) the southeast to northeast prevailing wind direction during the deposition period; (ii) a gentle paleotopographic slope in the W-DS unit, while a steep one in the E-HG unit; (iii) a climate shift toward more humid climatic condition from Lower to Upper Tongbomiao Formation intensified hydrodynamic conditions that were able to rework the sediments distributed in the W-DS unit. Finally, we discuss their implications for the future development of shoreline morphology of continental lakes affected by a monodirectional prevailing wind.
Arc-arc collision in the Central Asian Orogenic Belt: insight from the eastern segment of the Irtysh Shear Zone, NW China.
Authors: Hu Wanwan , Li Pengfei
Published: March 2021

As the largest accretionary orogen, the Central Asian Orogenic Belt (CAOB) involved episodic accretion/collision of arc terranes or microcontinental blocks from Neoproterozoic to late Paleozoic. Understanding the time and processes of such collisional events is crucial for the tectonic reconstruction of the CAOB. Here we focus on the Irtysh Shear Zone that represents the suture of the Peri-Siberian orogenic system (Chinese Altai Orogen) with the Kazakhstan orogenic system/East Junggar Terrane. On a basis of a combined structural and chronological study along the eastern segment of the Irtysh Shear Zone (Qinghe area), we reconstructed the collisional processes of the Chinese Altai Orogen with an intra-oceanic island arc of the East Junggar Terrane. Our results show that the oceanic basin between the Chinese Altai Orogen and the East Junggar Terrane was completely consumed in the late Carboniferous. The following arc-arc collision was characterized by early stage of orogen-perpendicular contraction, followed by orogen-parallel extension and transpressional deformation. The orogen-parallel extension, which is demonstrated by originally sub-horizontal foliation and associated orogen-parallel stretching lineation, may have be responsible for Permian high-temperature metamorphism and extensive magmatism in the southern Chinese Altai. On a scale of the western CAOB, the sinistral kinematics of the Irtysh Shear Zone, together with dextral shearing farther south in the Tianshan, suggests eastward tectonic wedging in the Permian, possibly in response to the coeval convergence of the Siberian, Baltic, and Tarim cratons.

E-mail addresses: pengfeili@gig.ac.cn, pengfeili2013@gmail.com (P. Li).

Acknowledgements: this study was financially supported by the National Natural Science Foundation of China (41872222), the National Key Research and Development Program of China (2017YFC0601205), Hong Kong Research Grant Council (HKU17302317) and a project from Guangdong Province (2019QN01H101).
The potential for geothermal lithium in Italy
Authors: Lattanzi Pierfranco , Dini Andrea , Ruggieri Giovanni , Trumpy Eugenio
Published: March 2021

Italy has never been a lithium (Li) producer, and the potential for “hard rock” deposits is moderate at best. On the other hand, the increasing demand for Li-based rechargeable batteries fostered new interest in this metal, and prompted the quest for alternative resources. The extraction of Li from geothermal brines (“geothermal lithium”) is currently considered in several countries, including, in Europe, France, Germany, and UK (EGEC, 2020).

Italy has vast geothermal resources, and there is a potential for “geothermal lithium” as well. A preliminary survey of literature data pointed out several occurrences of fluids with Li contents up to hundreds of mg/L. Among high-enthalpy fluids, we point out those of Cesano, Mofete, and Latera. At Cesano, geothermal fluids contain about 350 mg/L lithium (Calamai et al., 1976). Early studies conducted in the past century (Pauwels et al., 1990) suggested the feasibility of lithium recovery from these fluids. Even higher contents (480 mg/L) occur in the deep reservoir at Mofete (Guglielminetti, 1986), whereas fluids in the shallow and intermediate reservoir in the same field contain 28 to 56 mg/L. Geothermal fluids at Latera have somewhat lower contents (max 13.5 mg/L; Gianelli and Scandiffio, 1989). Several low-enthalpy thermal waters in Emilia-Romagna, Sardinia, Sicily and Tuscany also show significant (> 1 mg/L) Li contents (max 96 mg/L at Salsomaggiore; Boschetti et al., 2011). There are no published Li data for high-enthalpy fluids at Larderello; however, evidence of Li-rich fluids was found in fluid inclusions in hydrothermal minerals (Cathelineau et al., 1994). Moreover, the shallow (ca. 3.5 km) granitoid body underlying the field contains a Li-rich (about 1,000 ppm) biotite (A. Dini, unpublished data); it has been estimated that such rock may contain as much as 500 g Li per cubic meter.

 

References

Boschetti T., et al. - Aquat Geochem (2011) 17:71–108

Calamai A., et al. - Proc. U.N. Symp. Development Use Geotherm. Energy, S. Francisco, USA (1976), 305-313

Cathelineau M., et al. – Geochim. Cosmochim. Acta (1994) 58: 1083-1099

EGEC (European Geothermal Council). https://www.egec.org/time-to-invest-in-clean-geothermal-lithium-made-in-europe/. Accessed December 2, 2020.

Gianelli G., Scandiffio G. - Geothermics (1989) 18: 447-463

Guglielminetti M. - Geothermics (1986) 15: 781-790

Pauwels H., et al. - Proc. 12th New Zealand Geothermal Workshop (1990), 117-123
Fate of pesticide residues in vegetative filter strips in long-term exposure assessments: VFSMOD development and analysis
Authors: Muñoz-Carpena Rafael , Reichenberger Stefan , Sur Robin , Hammel Klaus
Published: March 2021

Inclusion of quantitative mitigation of pesticides in regulatory environmental risk assessment (ERA) using common agricultural field conservation practices is a critical need recently identified by experts in North America and EU [1]. Currently, mitigation by vegetative filter strips (VFS) is available by coupling the event-based model VFSMOD in continuous simulations within current long-term higher-tier surface water ERA frameworks (EU FOCUS SWAN, US EPA PWC, PRMA Canada, California CDPR PREM, etc.). In this case, the field management and pesticide-laden surface runoff at the edge of the field is calculated by the model PRZM and VFSMOD routes it from the edge of field through a VFS of desired characteristics to estimate potential load reductions before entering the aquatic environment, simulated by the receiving water body model (FOCUS TOXSWA, EPA VVWM). While under proper settings VFS could effectively reduce pesticide concentrations in surface water below thresholds of concern- what happens to the residues trapped in the VFS? The current ERA VFS framework uses a highly risk-conservative assumption, whereby the pesticide trapped in the VFS undergoes degradation between storm events and the surface residue (soil mixing layer and adsorbed to trapped sediment) is remobilized in full and added to the incoming pesticide load in the next event in the series. While risk conservative, this initial approach is not consistent with the nonuniform pesticide redistribution and extraction with depth used in the model PRZM within current ERA, and it has also been found too conservative for highly sorbed compounds with high specific toxicity like pyrethroids and others. The objective of this study is to develop a complete VFSMOD component to quantify the fate of VFS pesticide residues between runoff events for use in long-term ERA simulations. This includes realistic assumptions of the fate of the residues, including non-linear pesticide redistribution in the soil, mass balance of the VFS soil mixing layer and sediment trapped, degradation between runoff events, and partial remobilization and carryover of the remaining residue to the next event. Initial sensitivity and limited testing with existing field data are discussed.
Hazardous calving event on Isfallsglaciären in Northern Sweden as a result of climate warming
Authors: Holmlund Per , Kirchner Nina , Mannerfelt Erik
Published: March 2021

Isfallsglaciären in Northern Sweden is a steep polythermal valley glacier located in the Kebnekaise Mountains, which is well studied and thoroughly observed because its proximity to Tarfala Research Station run by Stockholm University. Isfallsglaciären is also included in the Swedish monitoring program for glaciers reported to WGMS.

The glacier advanced during the 1990s, but continues to recede and thin at a high rate since the turn of the century. On August 26, 2018, a 5x 105 m3  large portion of Isfallsglaciärens ice tongue decoupled from the main glacier and began to slide down-valley. Within 5 days, a 50 m wide gap had formed which increased to a width of c. 80 m later during the autumn. The front of the decoupled ice section advanced 50 m (timeframe?) over moderately inclined bed topography, and came eventually to a halt, without developing into an ice avalanche. The upstream cliff of the main glacier advanced first at a high rate and then progressively slowed down forming a new glacier front. [NK1] 

The event is very well documented by recurrent aerial photography taken during 2016-2020, as well as more frequent inage acquisition a few weeks before, and shortly after, the event. The photos have been analyzed using structure-from-motion photogrammetry to reveal the magnitude of change at a decimeter-level.

Departing from a description of this event, we discuss the impact of hazardous changes on glaciers becoming steeper and thinner due to recession, as well as complications arising for glacier front monitoring as part of the WGMS program.

Similar events have been reported at glaciers elsewhere in Sweden but these events are less well documented and do not influence the monitoring program. In this paper we will describe how data have been handled and inspire to similar studies in any glacier area. We will also discuss the issue in a glacier monitoring perspective.
Influence of soil factors on the microbiome of Rendzic Leptosols chronosequence in the Crimean Peninsula
Authors: Kimeklis Anastasiia , Gladkov Grigory , Zverev Aleksei , Kichko Arina , Andronov Evgeny , Ergina Elena , Kostenko Igor , Abakumov Evgeny
Published: March 2021

Pedogenesis depends on multiple factors, such as climate, vegetation, topography, parent material. Some of these factors are zonal, meaning they are determined by climate zone. But some factors are intrazonal, meaning that it has the same impact on soil formation in different climate zones. One example is parent material. The other peculiar feature of a parent material is that it determines the rates of pedogenesis. In this regard, Rendzic Leptosols – are intrazonal slowly developing soils formed on a limestone bedrock. In this study we approached the dynamics of microbiome formation in a chronosequence of these soils collected in Crimean Peninsula using analysis of 16S rRNA gene libraries and quantitative PCR. The chronosequence included benchmark soil, 700 year-old soil from the ancient city of Eski-Kermen, 70 year-old soil from WWII trenches and 50 year-old soil from the open quarry screenings. Our research demonstrated that soil type on a limestone rock is the driving force behind microbiome shaping, without any apparent influence of its age. Dominant phyla for all soil sites were Actinobacteria, Proteobacteria, Acidobacteria, Bacteroidetes, Thaumarchaeota, Planctomycetes, Verrucomicrobia and Firmicutes. Alpha diversity was similar across sites and tended to be higher in topsoil. Beta diversity showed that microbiomes diverged according to the soil site and the soil horizon. CCA analysis, in combination with PERMANOVA, linked differences in microbiomes to the nutrients associated with the soil horizon, and our analysis showed that the reactive component of the soil microbiome shifted simultaneously in both soil horizons between different soil sites.

The work was supported by the grant of the Russian Scientific Foundation, project 17-16-01030.
Changing sensitivity of global vegetation productivity to hydro-climate drivers
Authors: Li Wantong , Forkel Matthias , Migliavacca Mirco , Reichstein Markus , Walther Sophia , Denissen Jasper , Orth René
Published: March 2021

Terrestrial vegetation couples the global water, energy and carbon exchange between the atmosphere and the land surface. Thereby, vegetation productivity is determined by a multitude of energy- and water-related variables. While the emergent sensitivity of productivity to these variables has been inferred from Earth observations, its temporal evolution during the last decades is unclear, as well as potential changes in response to trends in hydro-climatic conditions. In this study, we analyze the changing sensitivity of global vegetation productivity to hydro-climate conditions by using satellite-observed vegetation indices (i.e. NDVI) at the monthly timescale from 1982–2015. Further, we repeat the analysis with simulated leaf area index and gross primary productivity from the TRENDY vegetation models, and contrast the findings with the observation-based results. We train a random forest model to predict anomalies of productivity from a comprehensive set of hydro-meteorological variables (temperature, solar radiation, vapor pressure deficit, surface and root-zone soil moisture and precipitation), and to infer the sensitivity to each of these variables. By training models from temporal independent subsets of the data we detect the evolution of sensitivity across time. Results based on observations show that vegetation sensitivity to energy- and water-related variables has significantly changed in many regions across the globe. In particular we find decreased (increased) sensitivity to temperature in very warm (cold) regions. Thereby, the magnitude of the sensitivity tends to differ between the early and late growing seasons. Likewise, we find changing sensitivity to root-zone soil moisture with increases predominantly in the early growing season and decreases in the late growing season. For better understanding the mechanisms behind the sensitivity changes, we analyse land-cover changes, hydro-climatic trends, and abrupt disturbances (e.g. drought, heatwave events or fires could result in breaking points of sensitivity evolution in the local interpretation). In summary, this study sheds light on how and where vegetation productivity changes its response to the drivers under climate change, which can help to understand possibly resulting changes in spatial and temporal patterns of land carbon uptake.
East‐Central Asian Climate Evolved With the Northward Migration of the High Proto‐Tibetan Plateau
Authors: Zhu Chenguang
Published: March 2021

The evolution of Cenozoic climate patterns in Asia has been linked to uplift of the Tibetan Plateau (TP), retreat of the Paratethys Sea, and global cooling. However, less attention has been placed on the latitudinal change of the TP. Here we report new climate modeling to explore how modern climate changes as a function of topographic growth and spatial migration of the TP. Our results show that the northward displacement of the uplifted proto‐TP within the subtropics can signifificantly affect the wind and precipitation pattern over East‐Central Asia. By compiling proxy‐based climatic records, paleolatitudinal and paleoelevational evolution models of the proto‐TP, and in comparison with previous modeling under a global paleogeography, we suggest that the northward migration of the proto‐TP in the Paleogene could have intensifified the aridity in Central Asia, but its inflfluence on East Asian precipitation and monsoonal circulation could be dependent on the paleogeography and other boundary conditions.
Equatorial Ionospheric Irregularities Observed by COSMIC 2 and GOLD Missions
Authors: Wu Qian , Braun John , Schreiner William , Sokolovskiy Sergey , Cherniak Iurii , Zakharenkova Irina , Pedatella Nick , Chou Min-yang , Hunt Doug
Published: March 2021

Equatorial ionospheric irregularities is an important space weather phenomenon, which can disrupt GNSS and communication systems. COSMIC 2 GNSS RO observations are affected via scintillations in signal amplitudes and phases. At the same time, we can use these scintillations to monitor and geolocate the ionospheric irregularities, which are of great value to the space weather services. Geolocation of the irregularities based on the RO signals is difficult, as any irregularities along the line between the GNSS and RO satellite can cause scintillation. Several geolocation methods are known. A back propagation (BP) method to geolocate the irregularities originally developed in 2001 and applied for GPS/MET RO data is being modified and applied for COSMIC 2 scintillation data. Because the equatorial irregularities are often associated with plasma bubbles, which are visible to the NASA UV imager GOLD, we have been using the GOLD images to validate the BP geolocation method.    In this presentation, we will show the progress of recent validation effort of the BP geolocation method by comparing the COSMIC 2 geolocated irregularities with plasma bubbles in GOLD UV observations. Though, GOLD observations are only available in the American sector, COSMIC 2 observations can be used geolocate ionospheric irregularities throughout the equatorial and low latitudes
Viscous strength of hcp iron at conditions of Earth’s inner core
Authors: Ritterbex Sebastian , Tsuchiya Taku
Published: March 2021

The Earth’s inner core is primarily composed of solid iron and is exposed to pressures of ~330-360 GPa and to temperatures corresponding to that of the surface of the sun. Its transport and rheological properties determine the rotational dynamics and deformation of the inner core. However, the rheology of the inner core is poorly understood. In a recently published paper in Scientific Reports (1Ritterbex & Tsuchiya 2020), we propose a theoretical mineral physics approach based on the density functional theory to constrain the viscosity of hexagonal close packed (hpc) iron, the most likely phase of iron stable in the inner core. Since plastic deformation is rate-limited by atomic diffusion at the extreme pressure and temperature conditions of Earth’s center, we quantify self-diffusion in hcp iron non-empirically. Results are used to model the rate-limiting creep behavior of hcp iron, suggesting dislocation creep to be a potential mechanism driving inner core deformation which might contribute to the observed seismic anisotropy of the inner core. The associated viscosity agrees well with geodetic estimates supporting that the inner core is significantly less viscous than Earth’s mantle. We demonstrate that the predicted low viscosity of hcp iron is consistent with a strong gravitational coupling between the inner core and mantle compatible with seismic observations of small fluctuations in the inner core rotation rate. We will discuss why the inner core is too weak to undergo translational motion, one of the hypotheses to explain the hemispherical patterns of seismic anisotropy in the inner core. Instead, our results provide evidence that mechanical stresses of tens of pascals are sufficient to deform hcp iron by dislocation creep at extremely low geological strain rates, comparable to the candidate forces able to drive inner core convection.

1S. Ritterbex and T. Tsuchiya (2020). Viscosity of hcp iron at Earth's inner core conditions from density functional theory. Scientific Reports 10, 6311. [doi:10.1038/s41598-020-63166-6]
Application of Xin'anjiang Model and Wetspa Model in the Inflow Forecasting of Shiquan Reservoir
Authors: Cai Siyu , Yuan Ruifang , Liao Weihong , Wu Liang
Published: March 2021

In order to improve the accuracy of the inflow forecasting of Shiquan Reservoir in the Han River Basin, this paper compared the application effects of Xin'anjing model and Wetspa model. The study collected the rainfall and runoff data from 2009 to 2015, as well as the DEM, land use and soil data with 1000´1000m grid size. The model calibration and verification periods were from 2009 to 2012 and from 2013 to 2015, respectively. In addition to using the runoff depth and the determination coefficient to evaluate the accuracy of the two models, the flow relative error CR1, model confidence coefficient CR2, Nash-Sutcliffe efficiency CR3, logarithmic version of Nash-Sutcliffe efficiency CR4 for low flow, improved Nash-Sutcliffe efficiency CR5 for high flow were adopted to analyze the simulation results of the two models. The results showed that the simulation results of the Wetspa model could be used as a supplement to the simulation results of the Xin'anjiang model, providing high-precision flood forecasting results for the scheduling decisions of Shiquan Reservoir in terms of time and space.
Global random walk solvers for fully coupled flow and transport in saturated/unsaturated porous media
Authors: Suciu Nicolae , Illiano Davide , Prechtel Alexander , Radu Florin
Published: March 2021

We present new random walk methods to solve flow and transport problems in saturated/unsaturated porous media, including coupled flow and transport processes in soils, heterogeneous systems modeled through random hydraulic conductivity and recharge fields, processes at the field and regional scales. The numerical schemes are based on global random walk algorithms (GRW) which approximate the solution by moving large numbers of computational particles on regular lattices according to specific random walk rules. To cope with the nonlinearity and the degeneracy of the Richards equation and of the coupled system, we implemented the GRW algorithms by employing linearization techniques similar to the L-scheme developed in finite element/volume approaches. The resulting GRW L-schemes converge with the number of iterations and provide numerical solutions that are first-order accurate in time and second-order in space. A remarkable property of the flow and transport GRW solutions is that they are practically free of numerical diffusion. The GRW solvers are validated by comparisons with mixed finite element and finite volume solvers in one- and two-dimensional benchmark problems. They include Richards' equation fully coupled with the advection-diffusion-reaction equation and capture the transition from unsaturated to saturated flow regimes.  For completeness, we also consider decoupled flow and transport model problems for saturated aquifers.
Energetic Particle Sounding of the Magnetopause Deformed by a Hot Flow Anomaly: MMS Observations
Authors: Zhang Hui
Published: March 2021

Hot flow anomalies (HFAs), which are frequently observed near the Earth’s bow shock, are phenomena resulting from the interaction between interplanetary discontinuities and the Earth’s bow shock. Such transient phenomena upstream of the bow shock can cause significant deformation of the bow shock and the magnetopause, generating traveling convection vortices, field-aligned currents, and ULF waves in the Earth’s magnetosphere. A large HFA lasting about 16 minutes was observed by MMS on November 19, 2015. In this study, energetic particle sounding method with high time resolution (150 ms) Fast Plasma Investigation (FPI) data is used to determine the deformed magnetopause distances, orientations, and structures during the interval when MMS crossed the deformed magnetopause. The estimated radius of curvature of the deformed magnetopause is 2.2 RE.
NMME-based Assessment of Prediction Skills of US Summertime Droughts and Pluvials: Role of Near-surface Temperature Prediction Skill
Authors: Kam Jonghun , Kim Sungyoon , Roundy Joshua
Published: March 2021

This study used the North American Multi-Model Ensemble (NMME) system to understand the role of near surface temperature in the prediction skill for US climate extremes. In this study, the forecasting skill was measured by anomaly correlation coefficient (ACC) between the observed and forecasted precipitation (PREC) or 2-meter air temperature (T2m) over the contiguous United States (CONUS) during 1982–2012. The strength of the PREC-T2m coupling was measured by ACC between observed PREC and T2m or forecasted PREC and T2m over the CONUS. This study also assessed the NMME forecasting skill for the summers of 2004 (spatial anomaly correlation between PREC and T2m: 0.05), 2011 (-0.65), and 2012 (-0.60) when the PREC-T2m coupling is weaker or stronger than the 1982–2012 climatology (ACC:-0.34). This study found that most of the NMME models show stronger (negative) PREC-T2m coupling than the observed coupling, indicating that they fail to reproduce interannual variability of the observed PREC-T2m coupling. Some NMME models with skillful prediction for T2m show the skillful prediction of the precipitation anomalies and US droughts in 2011 and 2012 via strong PREC-T2m coupling despite the fact that the forecasting skill is year-dependent and model-dependent. Lastly, we explored how the forecasting skill for SSTs over north Pacific and Atlantic Oceans affects the forecasting skill for T2m and PREC over the US. The findings of this study suggest a need for the selective use of the current NMME seasonal forecasts for US droughts and pluvials.
Linking variable Nordic Seas inflow to upstream circulation anomalies
Authors: Asbjørnsen Helene , Johnson Helen , Årthun Marius
Published: March 2021

The inflow across the Iceland-Scotland Ridge determines the amount of heat supplied to the Nordic Seas from the subpolar North Atlantic (SPNA). Variability in inflow properties and volume transport at the ridge influence marine ecosystems and sea ice extent further north. The predictability of such downstream impacts depends on how variability at the ridge relate to large-scale ocean circulation changes in the North Atlantic. Here, we identify the upstream pathways of the Nordic Seas inflow, and assess the mechanisms responsible for interannual inflow variability. Using an eddy-resolving ocean model hindcast and a Lagrangian analysis tool, numerical particles are released at the ridge during 1986-2015 and tracked backward in time. Overall, 64% of the mean inflow volume transport has a subtropical origin and 26% has a subpolar or Arctic origin. The local instantaneous response to the NAO is important for the overall transport of both subtropical and Arctic-origin waters at the ridge. In the years before reaching the ridge, the subtropical particles are influenced by atmospheric circulation anomalies in the gyre boundary region and over the SPNA, forcing shifts in the North Atlantic Current (NAC) and the subpolar front. An equatorward shifted NAC and westward shifted subpolar front correspond to a warmer, more saline inflow. Wind stress curl anomalies over the SPNA also affect the amount of Arctic-origin water re-routed from the Labrador Current toward the Nordic Seas. A high transport of Arctic-origin water is associated with a colder, fresher inflow across the Iceland-Scotland Ridge. The results thus demonstrate the importance of gyre dynamics and wind forcing in affecting the Nordic Seas inflow properties and volume transport.