bluuebunny/crossref_metadata_2025 huggingface dataset:
Pyrite Oxidation Controlled Siderophile Element Accumulation on the K-Pg Boundary at El Kef, Tunisia
Authors: Humayun Munir , Sillitoe-Kukas Steffanie , Adatte Thierry , Keller Gerta
Published: March 2021

In a transformative contribution, Alvarez et al. (1980) discovered the iridium anomaly at several K-Pg boundary locations that they attributed to an extraterrestrial impact that triggered the end-Cretaceous extinction. The absence of a suitable mechanism by which to concentrate siderophile elements in the boundary clay drove the argument for an extraterrestrial origin of the iridium. They made the observation that fallout from a fireball would be expected to create a uniform distribution of Ir in the clay layer and puzzled over the scale of lateral variation in Ir observed even then. A detailed global study of the siderophile element (Ru, Rh, Pd, Ir, Pt Au) distribution at the K-Pg boundary found non-chondritic patterns concluding that some post-depositional process(es) must have affected the elemental distribution (Goderis et al., 2015). Such processes would mobilize siderophile elements into the surrounding strata. Here, we applied laser ablation ICP-MS, a microanalytical technique, to investigate the distribution of 60 elements, with an emphasis on the siderophile elements, in a vertical transect at the K-Pg boundary at El Kef, Tunisia, to search for elemental transport in or out of the K-Pg clay layer. The K-Pg boundary at El Kef consists of irregular mixed layers of clay, goethite and gypsum with marls above and below. The siderophile elements are concentrated in the goethite-rich component with a distinctly terrestrial crust pattern, albeit super-enriched, with prominent negative Pt anomalies indicative of deposition from an oxidized solution. The Fe/Se ratio indicates an origin of the goethite by oxidation of sedimentary pyrite. Iron oxyhydroxides are effective substrates for the binding of trace metal oxyanions from solution. The extreme enrichment of siderophile elements reflects long-term concentration of siderophile elements from percolating oxidized groundwaters at El Kef. The sulfuric acid produced by pyrite oxidation was neutralized by calcium carbonate in the marls to form gypsum. Selenium (normally a sulfur analog) is undetectable in the El Kef gypsum endmember (Se/S~0), unlike marine gypsum, supporting a formation by pyrite oxidation. This observation potentially explains the ubiquitous non-chondritic siderophile patterns observed globally and the variable Ir enrichments that puzzled geochemists since Alvarez et al. (1980). In view of this observation, siderophile element enrichment in the K-Pg layer can no longer be taken as unambiguous evidence of an extraterrestrial impact.
Influence of local splitting behavior at intersections on infiltration in an unsaturated fracture network 
Authors: Xue Song , Yang Zhibing , Chen Yi-Feng
Published: March 2021

Understanding and predicting the macro-scale flow characteristics in the fractured vadose zone is of great importance for subsurface hydrological applications. Here we develop a network model to study infiltration in unsaturated fracture networks. We consider an idealized honeycomb-like fracture network composed of a series of Y-shaped and inverted Y-shaped intersections. At the scale of intersections, liquid storage/release and splitting/convergence behaviors are modeled according to local splitting relationships obtained from detailed laboratory work and numerical simulations. By varying the splitting relationships, the influence of local flow behaviors on large scale flow structures is systematically investigated. We find that when the water split tends to split equally at the intersection, a divergent flow structure forms in the network. Conversely, unequal splitting leads to preferential pathways. We also find that an avalanche infiltration mode, i.e., sudden release of a large amount of water from the network, emerges spontaneously, and is modulated by the local splitting behavior. The pathways of preferential flow is controlled by the liquid volume triggered by avalanches and the network structure. The improved understanding from this study may shed new light on the complex flow dynamics for unsaturated flow in fractured media.
Evaluation of the risk of the breaking of check dam based on a scorecard model.
Authors: liu beilei , li peng , li zhanbin , yang yuanyuan , long shaobo , feng yangfan
Published: March 2021

Check dam is a line of defense in the comprehensive watershed management system, but with the extended operation time, the operational risk of check dam increases, coupled with the frequent occurrence of sudden heavy rainfall under the influence of climate change in recent years, further increasing the risk of dam break.

In this study, to address the current problem of untimely detection of potential dam break risk of check dam in China, we use the common variable screening based on WoE (Weight of Evidence) and IV (Information Value), establish a score card model based on logistic regression method, use KS curves and statistics, and AUC values for model evaluation, and analyze the 2016 From 22:00 on August 16 to 12:00 noon on August 17, 2016, a dam break was formed by a large rainstorm in Dalat Banner.

The following conclusions were obtained: The IV values of each variable, such as control area, total storage capacity, siltation area, storage volume, and maximum rainfall, were all greater than 0.1, and each variable had more than moderate predictive power as a function of the breaking of check dam, that is, each factor had an effect on the breaking of check dam.The IV values of precipitation factors are higher than those of check dam factors. The influence probability of precipitation factors on the breaking of check dam is about 67%, and the influence probability of check dam factors on the breaking of check dam is about 33%.Precipitation is a direct factor affecting the breaking of check dam, and the maximum 6-hour precipitation has the most significant effect; among the check dam factors, the control area, storage volume, and flood storage capacity have a greater effect on the breaking of check dam, accounting for more than 10%, while the siltation volume and depth have a smaller effect on the breaking of check dam, accounting for 2.85% and 2.89% respectively.Very low risk which check dam with a score of 95 or higher account for about 43%, low risk for 28%, average risk for 15%, and higher risk for 7%. Very high risk accounted for 5% and there was only one dam with danger which is rated below 10.

This study aims to monitor and warn the operation of check dam to ensure the safe operation of the check dam system and maintain the ecological security of the Loess Plateau.
Climatology of the Heat Low and the Intertropical Discontinuity in the Arabian Peninsula
Authors: Fonseca Ricardo , Francis Diana , Nelli Narendra , Thota Mohan
Published: March 2021

The climatological state and the seasonal variability of the Arabian Heat Low (AHL) and the Intertropical Discontinuity (ITD) are investigated over the Arabian Peninsula using the 1979-2019 ERA-5 reanalysis data. The AHL is a summertime feature, mostly at 15º-35ºN and 40º-60ºE, exhibiting a clear strengthening over the last four decades in line with the observed increase in surface temperature. However, no clear shift in its position is detected. The AHL has a center over the Arabian Gulf and eastern Arabian Peninsula, co-located with the highest surface temperatures, and another over central Saudi Arabia, driven by low-level wind convergence and subsequent increase in atmospheric thickness. The ITD is the boundary between the hot and dry desert air and the cooler and more moist air from the Arabian Sea. It lies along the Arabian Peninsula’s southern coastline in the cold season but reaches up to 28º N between 50º - 60º E in the summer months. While the former has a rather small diurnal variability, the latter shows daily fluctuations of up to 10º. The ITD exhibited a weak northward migration in the 41-year ERA-5 period, likely driven by the increased sea surface temperatures in the Arabian Sea. On interannual timescales, the El Niño-Southern Oscillation, the Indian Ocean Dipole, and solar-geomagnetic effects play an important role in the AHL’s and ITD’s variability.
Interannual variability of typhoon-induced northeast Asian marginal seas-mean sea level
Authors: Han MyeongHee , Nam SungHyun
Published: March 2021

As connected through relatively narrow and shallow straits, inflow and outflow volume transports of the northeast Asian marginal seas (NEAMS) are strongly forced to yield significant convergence or divergence and resulting rise or drop in spatially-averaged sea level. Here, we examined interannual variations of August NEAMS-mean sea level observed from satellite altimetry from 1993 to 2019. Typhoon activity was found to be a primary factor controlling the interannual variations of NEAMS-mean sea level in August. Relatively high August sea level over the NEAMS is derived in years when more typhoons pass through the East China Sea (Period H) due to typhoon-induced Ekman transports. The resultant NEAMS-mean sea level is a few cm higher than that during the years of less or no typhoon activity in the East China Sea (Period L). This study highlights the importance of typhoon (hurricane) activity on interannual variations of regional sea level in the mid-latitude and semi-enclosed marginal seas.
Climate variability following large volcanic eruption: CMIP6 model investigation
Authors: Malinina Elizaveta , Gillett Nathan
Published: March 2021

Volcanic eruptions are an important driver of climate variability. Multiple literature sources have shown that after large explosive eruptions there is a decrease in global mean temperature, caused by an increased amount of stratospheric aerosols which influence the global radiative budget. In this study, we investigate the changes in several climate variables after a volcanic eruption. Using ESMValTool (Earth System Model Evaluation Tool) on an ensemble of historical simulations from CMIP6, such variables as global mean surface temperature (GMST), Arctic sea ice area and Nino 3.4 index were analyzed following the 1883 Krakatoa eruption. While there is a definite decrease in the multi-model mean GMST after the eruption, other indices do not show as prominent change. The reasons for this behavior are under investigation. 
Rapid silicon accumulation affects carbon-based plant defences and enhances plant resistance to a global insect pest 
Authors: Waterman Jamie , Cibils-Stewart Ximena , Hall Casey , Mikhael Meena , Cazzonelli Christopher , Hartley Susan , Johnson Scott
Published: March 2021

1) Crop loss due to insect herbivory is one of the largest challenges facing the agricultural industry. As herbivore populations continue to grow in light of global change, securing crop resources is becoming increasingly critical. Silicon (Si) has been shown to effectively mitigate the adverse effects of herbivores such as the cotton bollworm, Helicoverpa armigera (Lepidoptera: Noctuidae), in crop species (namely grasses), that have evolved the ability to uptake large amounts of Si through their roots and accumulate it in aboveground tissues. Nevertheless, the effectiveness of Si accumulation as a plant defence against herbivory in the short term, and its consequential effects on alternative defence responses, remain unclear.
2) We conducted two discrete experiments to determine the short-term dynamics of Si, chemical defences and resistance to herbivory in the model grass, Brachypodium distachyon: 1) Both Si-supplemented (+Si) and control (-Si) plants were treated with methyl jasmonate (MeJA) as a form of simulated herbivory and we measured the interplay of Si accumulation, the phytohormones jasmonic acid (JA) and salicylic acid (SA), and carbon-based defences over 24 hr. 2) We exposed H. armigera larvae to B. distachyon plants grown under three conditions: +Si, -Si, or treated with Si only once H. armigera feeding began. We measured the effect of short-term plant exposure to Si on H. armigera performance and plant resistance.
3) MeJA-induced Si accumulation occurred as early as 6 hr after treatment via increased JA concentrations. Si supplementation decreased SA concentrations, which could have implications on additional downstream defences. We show a trade-off between Si and phenolics in untreated plants, but this relationship was weakened upon MeJA treatment. Although foliar Si concentrations remained lower, within 72 hr of exposure to Si, plants obtained virtually the same level of resistance to H. armigera as plants exposed to Si for over 30 days. H. armigera feeding also accelerated Si deposition after 6 hr of exposure to Si, however, in as little as 24 hr, levels of Si deposition were similar to plants exposed to Si long term.
4) In addition to its well-documented role as a long-term defence against herbivores, we demonstrate that, over short-term temporal scales, Si accumulation responds to herbivore signals and impacts on plant defence machinery. Further, we provide novel evidence that plants can rapidly incorporate Si into their tissues to mitigate the adverse effects of herbivory as effectively as plants exposed to Si long term.
Applying machine learning to satellite imagery and vessel-tracking data to detect chronic oil pollution from ships at sea and identify the polluters
Authors: Raphael Jona , Eggleston Ben , Covington Ryan , Evanisko Tatianna , Bylsma Sasha , Amos John
Published: March 2021

Operational oil discharges from ships, also known as “bilge dumping,” have been identified as a major source of petroleum products entering our oceans, cumulatively exceeding the largest oil spills, such as the Exxon Valdez and Deepwater Horizon spills, even when considered over short time spans. However, we still don’t have a good estimate of

How much oil is being discharged;

Where the discharge is happening;

Who the responsible vessels are.

This makes it difficult to prevent and effectively respond to oil pollution that can damage our marine and coastal environments and economies that depend on them.

 

In this presentation we will share SkyTruth’s recent work to address these gaps using machine learning tools to detect oil pollution events and identify the responsible vessels when possible. We use a convolutional neural network (CNN) in a ResNet-34 architecture to perform pixel segmentation on all incoming Sentinel-1 synthetic aperture radar (SAR) imagery to classify slicks. Despite the satellites’ incomplete oceanic coverage, we have been detecting an average of 135 vessel slicks per month, and have identified several geographic hotspots where oily discharges are occurring regularly. For the images that capture a vessel in the act of discharging oil, we rely on an Automatic Identification System (AIS) database to extract details about the ships, including vessel type and flag state. We will share our experience

Making sufficient training data from inherently sparse satellite image datasets;

Building a computer vision model using PyTorch and fastai;

Fully automating the process in the Amazon Web Services (AWS) cloud.

The application has been running continuously since August 2020, has processed over 380,000 Sentinel-1 images, and has populated a database with more than 1100 high-confidence slicks from vessels. We will be discussing preliminary results from this dataset and remaining challenges to be overcome.

 

Our objective in making this information and the underlying code, models, and training data freely available to the public and governments around the world is to enable public pressure campaigns to improve the prevention of and response to pollution events. Learn more at https://skytruth.org/bilge-dumping/
Drivers of soil water repellency after wildfires: case study in the south-central Appalachian Mountains, US
Authors: Chen Jingjing , Strahm Brian , Stewart Ryan
Published: March 2021

Increasing frequency of wildfire in humid hardwood forests make it necessary to understand the occurrence and origin of soil water repellency in these systems, as wildfire-induced soil water repellency has been observed to severely impact many biophysical processes in other forest types. In this project, we studied two sites in the Appalachian Mountains, United States, (at Mount Pleasant Wildlife Refuge, Virginia, and Chimney Rock State Park, North Carolina) where wildfires occurred in late 2016. In each site, burned and unburned soils were evaluated for actual (in the field) and potential (in the laboratory) water repellency using the water drop penetration time method. In addition, samples were analyzed for organic carbon content (measured using C/N analyzer), hydrophobic functional groups (using Fourier transform infrared, FTIR), and their rank correlations (rs) based on multiple samples collected one year after the fires. We found that soil water repellency was substantial greater in burned soils in the first months after the fire, and persisted for the entire year in the more severely burned soils. We also determined that potential water repellency was much greater than actual water repellency, and that organic carbon content and hydrophobic functional groups were significantly correlated to potential water repellency (p < 0.0001). Correlations were stronger at Mount Pleasant (0.77 < rs <0.91) than at Chimney Rock (0.06 < rs < 0.70). For actual water repellency only had significant correlations with soil organic content at Mount Pleasant (p < 0.0001), and with hydrophobic functional groups (p < 0.0001) at both sites except the unburned soils at Chimney Rock. However, these correlations were weaker than with potential water repellency, likely due to the influence of soil water content. Altogether, this study provides new insight into the influence of soil organic matter and its composition on post-wildfire soil water repellency.
Deep learning for extracting water body from Sentinel-2 MSI imagery
Authors: Chou Shuren
Published: March 2021

Deep learning has a good capacity of hierarchical feature learning from unlabeled remote sensing images. In this study, the simple linear iterative clustering (SLIC) method was improved to segment the image into good quality super-pixels. Then, we used the convolutional neural network (CNN) to extract of water bodies from Sentinel-2 MSI data using deep learning technique. In the proposed framework, the improved SLIC method obtained the correct water bodies boundary by optimizing the initial clustering center, designing a dynamic distance measure, and expanding the search space. In addition, it is different from traditional extraction of water bodies methods that cannot achieve multi-level water bodies detection. Experimental results showed that this method had higher detection accuracy and robustness than other methods. This study was able to extract water bodies from remotely sensed images with deep learning and to conduct accuracy assessment.
Optimization of the time series surface deformation analysis using machine learning algorithms on the interferogram simulation data
Authors: Fadhillah Muhammad Fulki , Lee SeulKi , Lee Chang-Wook
Published: March 2021

Time-series InSAR techniques, such as Stanford Method for Persistent Scatterers (StaMPS) are commonly used to measure time-series surface deformation. This study presents a novel approach of optimized time series deformation analysis based on a support vector regression (SVR) algorithm and optimization Hot-Spot Analysis on persistent scatterers (PS). To examine the performances of the optimized process in time-series, we generated a synthetic interferogram using a Mogi model equation to construct a simulated surface deformation phase. Topography errors simulated orbital error and atmospheric error phases have been added to synthetic interferogram construction. All the synthetic interferogram based on Sentinel-1 SAR Image acquisition dates over Seoul, Korea. An SVR algorithm was used to find an optimum measurement point and reduce error points in time-series analysis. Then, the OHSA approach was implemented on the optimum measurement point through the analysis of Getis-Ord Gi* statistics. As the result, the optimization measurement point indicates refined results in the mean velocity deformation map and time-series graph. In addition, the detection accuracy can be improved by more than 10% with synthetic data. Then, the correlation coefficient between the optimization result and the deformation model shows a good correlation (> 0.8). Also, the standard deviation of time-series results can be reduced by more than 7% after optimizing the process. The proposed method is useful to detect a low deformation rate and can be implemented for several deformation cases.   
Variation of the concentration of particulate matter in the atmosphere and rainwater quality during precipitation at an urban site of southeast Korea
Authors: Park Hyemin , Yang Minjune
Published: March 2021

This study investigated the wet deposition of particulate matter (PM) for six precipitation events at Daeyeon dong, Busan, South Korea, from February 2020 to July 2020. The concentration of PM10 in the atmosphere was steadily measured before and after the precipitation. Rainwater samples were collected every 50 mL of each precipitation event using rainwater collecting devices and rainwater qualities (pH, electrical conductivity (EC), water-soluble ions (SO42-, NO3-, NH4+, Ca2+, etc.) were analyzed. For heavy rain events with strong rainfall intensities (>7.5 mm/h), the average PM10 reduction efficiency reached more than 68%. For the relatively weak (<5 mm/h) rainfall intensities, the PM10 reduction efficiencies were less than 40%. In all rainfall events, the average rainwater pH gradually increased over time from 4.3 to 5.0, while the average EC decreased from 81.9 to 12.1 µS/cm. The concentrations of all ions in the rainwater samples gradually decreased during precipitation. For heavy rain events, the acidity, EC, and concentrations of total water-soluble ions of initial rainwater samples were higher than those of later samples. This result indicates that the concentration of PM10 in the atmosphere was reduced by wet deposition.
Ionospheric Variability: Response to Sudden Stratospheric Warming events during Solar Cycle 24
Authors: Gupta Sumedha , Upadhayaya Arun Kumar , Siingh Devendraa
Published: March 2021

With low solar activity and unusual progression, Solar Cycle 24 lasted from December 2008 to December 2019 and is considered to be the weakest cycle in the last 100 years. During such quiet solar background conditions, the wave forcing from lower atmosphere will have a perceivable effect on the ionosphere. This study examines the ionospheric response to meteorological phenomenon of Sudden Stratospheric Warming (SSW) events during Solar Cycle 24 (Arctic winter 2008/09 to 2018/19). Ionospheric response to each of these identified warming periods is quantified by studying ground – based Global Positioning System (GPS) derived vertical Total Electron Content (VTEC) and its deviation from monthly median (ΔVTEC) for four longitudinal chains, selected from worldwide International GNSS service (IGS) stations. Each chain comprises of eight stations, chosen in such a way as to cover varied latitudes both in Northern and Southern Hemispheres. A strong latitude – dependent response of VTEC perturbations is observed after the peak stratospheric temperature anomaly (ΔTmax). The semidiurnal behaviour of VTEC, with morning increase and afternoon decrease, is mostly observed at near-equatorial stations. This vertical coupling between lower and upper atmosphere during SSW is influenced by prominent 13-14 days periodicities in VTEC observations, along with other periodicities of 7, 5, and 3 days. It is seen that the ionospheric response increases with increase in solar activity. Further, under similar ionizing conditions, quite similar ionospheric response is observed, irrespective of ΔTmax and type of SSW event being major or minor. However, under similar SSW strength (ΔTmax), no prominent pattern in ionospheric response is observed. The causative mechanism for the coupling processes in the atmosphere during these SSW events is discussed in detail.
Multiple transpolar auroral arcs reveal new insight about coupling processes in the Earth’s magnetotail
Authors: Zhang Qing-He , Zhang Yong-Liang , Wang Chi , Lockwood Michael , Yang Hui-Gen , Tang Bin-Bin , Xing Zan-Yang , Oksavik Kjellmar , Lyons Larry R. , Ma Yu-Zhang , Zong Qiu-Gang , Moen Jøran Idar , Xia Li-Dong
Published: March 2021

A distinct class of aurora, called transpolar auroral arc (TPA) (in some cases called “theta” aurora), appears in the extremely high latitude ionosphere of the Earth when interplanetary magnetic field (IMF) is northward. The formation and evolution of TPA offers clues about processes transferring energy and momentum from the solar wind to the magnetosphere and ionosphere during a northward IMF. However, their formation mechanisms remain poorly understood and controversial. We report a new mechanism identified from multiple-instrument observations of unusually bright, multiple TPAs and simulations from a high-resolution three-dimensional global MagnetoHydroDynamics (MHD) model. The observations and simulations show an excellent agreement and reveal that these multiple TPAs are generated by precipitating energetic magnetospheric electrons within field-aligned current (FAC) sheets. These FAC sheets are generated by multiple flow shear sheets in both the magnetospheric boundary produced by Kelvin-Helmholtz instability between super-sonic solar wind flow and magnetosphere plasma, and the plasma sheet generated by the interactions between the enhanced earthward plasma flows from the distant tail (less than -100 RE) and the enhanced tailward flows from the near tail (about -20 RE). The study offers a new insight into the complex solar wind-magnetosphere-ionosphere coupling processes under a northward IMF condition, and it challenges existing paradigms of the dynamics of the Earth’s magnetosphere.
Analysis of Energy Sources along the Kuroshio in the East of Taiwan Island and East China Sea 
Authors: Wang Ru , Hou Yijun , Liu Ze
Published: March 2021

The locations and generation mechanisms of energy sources in the Kuroshio were analyzed. The slope of the one-dimensional spectral energy density varies between -5/3 and -3 in the wavenumber range of 0.03-0.1 cpkm (wavelengths of approximately 209 to 63 km, respectively), indicating an inverse energy cascade in the Kuroshio; according to the steady-state energy evolution, an energy source which occurs at scale smaller than Rhines scale must be present. By analyzing the wavenumber-frequency spectrum, the period of higher kinetic energy (KE) is about 89-209 days and spatial scale is less than 0.03 cpkm. The locations of energy sources were identified with using the spectral energy transfer calculated by altimetry and model data. At the sea surface, the KE sources are mainly within 23.2°-25.2°N and 28°-30°N at less than 0.03 cpkm and 23.2°-23.6°N and 26°-30°N at 0.03-0.1 cpkm. The available potential energy (APE) sources are mainly within 22.2°-28°N and 28.6°-30°N at less than 0.03 cpkm and 29.2°-30°N at 0.03-0.1 cpkm. Wind stress and density differences (including buoyancy flux, temperature flux and salinity flux) are primarily responsible for the KE and APE sources, respectively. Beneath the sea surface, the energy sources are mainly above 400 m depth, and buoyancy flux plays a major role in the generation of energy sources. The energy cycle process can be summarized as follows: once an energy source is formed, to maintain a steady state, energy cascades (mainly inverse cascades) will be engendered.

 
Effects of upper-level background wind bias on Rossby waveguides, Rossby wave source hotspots, and predictability of the Silk Road pattern
Authors: Li Ronald Kwan Kit , Tam Chi-Yung , Lau Ngar-Cheung , Sohn Soo-Jin , Ahn Joong-Bae , O'Reilly Christopher
Published: March 2021

The Silk Road pattern (SRP) is a leading mode of atmospheric circulation over mid-latitude Eurasia during boreal summer. Its temporal phase is known to be unpredictable in many climate models. Previous studies have not reached a clear consensus on the role of sea surface temperature (SST) associated with SRP. To investigate role of SST on SRP formation, we begin by comparing reanalysis with seasonal hindcast experiments of the Pusan National University coupled climate model. 

Although SRP cannot be predicted temporally, the ensemble runs show potential predictability in SRP related to tropical Pacific SST. While reanalysis SRP is associated with North Atlantic SST anomalies, hindcast SRP is associated with tropical Pacific SST anomalies similar to El-Nino Southern Oscillation (ENSO). To explain the different SST associations, we propose two jet biases in the climate model which may affect Rossby wave propagation. Bias in North Atlantic jet exit results in a discontinuous waveguide from North Atlantic to Asia, which may hinder propagation of waves associated with North Atlantic SST to trigger SRP. In addition, bias in subtropical western Pacific westerlies reduces the evanescent region between subtropical western Pacific and Asian jet, which may favour westward dispersion of zonally elongated waves associated with ENSO SST to trigger SRP. Therefore, we propose that the role of SST on SRP can be substantially changed depending on fidelity of model upper-level background winds. 

To investigate more quantitatively the roles of waveguides and the Rossby wave sources (RWS), we perform wave-making experiments using an idealised barotropic model prescribed with two different upper-level background winds, namely from reanalysis and from climate model. By comparing with result using reanalysis background winds, the preferred forcing locations - RWS hotspots - of SRP are identified from all the RWS associated with SRP in reanalysis. In addition to previously identified hotspots from the literature, a new hotspot in central North Pacific is discovered which can force SRP by westward dispersion of zonally elongated Rossby wave. 

Wave-making result using climate model background winds reveals that the upper-level wind bias changes the RWS hotspots locations of SRP. Experimental result is consistent with theoretical analysis of waveguide bias, and support our conclusion that the relationship between SRP and SST can be substantially changed depending on model background winds bias. The impact of our study is that this sensitivity of SRP hotspots to background winds may reduce seasonal forecast skill of SRP in models with background winds bias. 
The geochemical consequences of mixing melts from contrast sources beneath the Jiaodebushan and Xiaogushan volcanoes, Wudalianchi volcanic field, Northeast China
Authors: Yasnygina Tatiana , Sun Yi-min , Rasskazov Sergei , Chuvashova Irina , Yang Chen , Xie Zhenhua , Ivanova Valeria
Published: March 2021

Potassic rocks from the Wudalianchi field are considered by some authors as derivatives of the mantle transition layer. However, this opinion is contradicted by the contrasting component composition of melts erupted in different volcanoes. From data of lead isotope compositions, the initial eruptions of lava flows 2.5–2.0 Ma ago were derived from the lithospheric Laoshantou and Gelaqiu model sources of about 1.88 Ga, while subsequent eruptions were derived from the Wohu source of about 0.15 Ga and the recent Molabu source (Rasskazov et al., 2020). Detailed sampling of volcanoes yielded geochemical evidence on both the individualization of sources beneath volcanoes and mixing of melts from contrasting sources. We present evidence on mixing of melts from the Gelaqiu, Wuhu, and Molabu sources beneath the Jiaodebushan Volcano and partial similarity of rock components from this volcano to material erupted in the Xiaogushan Volcano.

This work is supported by the RSF grant 18-77-10027.

Rasskazov S., Sun Y-M., Chuvashova I., Yasnygina T., Yang C., Xie Z., Saranina E., Gerasimov N., Vladimirova T. Trace-element and Pb isotope evidence on extracting sulfides from potassic melts beneath Longmenshan and Molabushan volcanoes, Wudalianchi, Northeast China. Minerals. 2020. V. 10: 319; doi:10.3390/min10040319
Efficiency of dust control products in suppression of wind-induced dust emission from soils
Authors: Katra Itzhak
Published: March 2021

Surfaces of disturbed soils are subjected to dust PM10 (particulate matter < 10 µm) emission by wind process regardless of human activities such as vehicles (wheels) traveling. However, there is little quantitative information on the efficiency of dust control products in suppression of wind-induced dust emission. The study aimed to fill this clear gap using wind-tunnel experiments under laboratory and field conditions. Diverse dust control products of synthetic and organic polymers (Lignin, Resin, Bitumen, PVA, Brine) were tested. In the first stage, the products were tested under controlled-laboratory conditions. In the second stage, the products were tested in unpaved roads of an active quarry after the transportation of quarry-haul trucks in two time points after the product application. The results show that in most of the plots the dust emission increases with the wind velocity. PM10 fluxes from the road surface in each plot were calculated to determine the effectiveness of the dust control products. Some products significantly reduced the dust emission, especially the magnesium chloride brine. Additional experiments revealed that the brine can be applied with reduced amount than that of the recommended amount while keeping on low dust emission.
Initial Calibration Results of the NIM Flight Spare Mass spectrometer for Exploration of Jupiter’s Icy Moons Exospheres
Authors: Föhn Martina , Tulej Marek , Galli André , Vorburger Audrey Helena , Lasi Davide , Riedo Andreas , Wurz Peter , Brandt Pontus , Barabash Stas
Published: March 2021

The search for life is one of the key topics in modern space science. The JUICE mission of the European Space Agency ESA will investigate Jupiter and its icy moons Ganymede, Callisto and Europa, with Europa being an example of a potentially habitable world around a giant gas planet. The Particle and Environment Package, PEP, on board of the JUICE spacecraft will investigate Jupiter’s icy moons and their environment. The Neutral gas and Ion Mass spectrometer NIM will investigate the icy moon’s exospheres to investigate their formation and the interaction processes of the exospheres with the moons’ surface and Jupiter’s strong magnetic field. It will enhance our understanding of the processes involved in the interactions of ion bombardment on the icy moons' surfaces. From these measurements, we will derive the moons’ surface composition and their formation processes.

NIM is a time-of-flight mass spectrometer with two particle entrances: an open-source entrance to measure neutral particles and ions directly and a close source entrance where neutral particles get thermalized before entering the sensor’s ionization region. This allows detecting of particles with high speeds. NIM has a specially designed ion storage source and an ion-mirror to double the flight distance of the produced ions by keeping the sensor at a minimal size.

In this contribution, we show calibration results of the NIM flight spare instrument on one hand operated with laboratory and on the other operated with flight electronics. We demonstrate the performance of NIMs ion-source, verify the performance of the closed-source antechamber. NIM has a demonstrated mass resolution of m/Δm 800.
Influence of pollutants on rheological characteristics of sediment flow
Authors: Zhang Yuanyuan , Gao Jianen , Gao Zhe , Kang Youcai , Wang Zhaorun , Wang Lu , Zhou Fanfan , Liu Sixuan , Li Xingyao , Ji Mingjuan
Published: March 2021

Abstract: In view of the weak research on the rheological characteristics involved in the variation of the fluid movement caused by the storm runoff carrying a large amount of pollutants and sediments, this study uses the NDJ-5S rotary viscometer and the self-made slim tube viscometer of Northwest Agriculture and Forestry University. On the basis of the research, the influence of pollutants on the rheological characteristics of high-concentration sandy water flow is studied. The results show that the NDJ-5S rotary viscometer can be used well under the sand content of less than 300kg/m3. The double vertical tube slim tube viscometer made by Northwest A&F University can better simulate the sand content of 0～800kg/m3; The structure of flocculation between particles in sandy water flow will affect the viscosity of muddy water, and the concentration of sediment and other pollutants will have a certain impact on flocculation. Under the same conditions, the concentration of pollutants increases (0～440kg/m3), the viscosity coefficient of fluid increases (90%～114%), and the variation of sand content from Newtonian body to Bingham body is about 300～400kg/m3, The influence of pollutants on the variation points of rheological properties is not significant.

Keywords: pollutants; sediment; variation; viscometer; Newtonian fluid; Bingham fluid

Funding: This study was funded by the National Natural Science Foundation of China (No. 41877078, 41371276), Key research and development project of Shaanxi Province (2020ZDLSF06-03-01), National Key Research and Development Program of China (No. 2017YFC0504703) and Knowledge Innovation Program of the Chinese Academy of Sciences (No. A315021615). 
Reconstructing Holocene vegetation-fire regimes in the Iberian Peninsula
Authors: Shen Yicheng , Harrison Sandy , Prentice Colin
Published: March 2021

Analyses of the regional controls representing climate, vegetation and human activities on modern burnt area in the Iberian Peninsula show that the vegetation properties that determine fuel availability are major influences on the occurrence of fire. This finding opens up the possibility of using pollen data to reconstruct past changes in fire regimes. We could then make use of the much greater abundance of pollen data compared to other sources of information on past fire regimes to constrain biomass-burning feedbacks to the carbon cycle and climate. We applied Tolerance-Weighted Averaging Partial Least-Squares (TWA-PLS) to derive quantitative relationships between pollen-taxon and charcoal abundances from 15 entities from the Iberian Peninsula, using core-top charcoal data and a generalized linear model of present-day fire probability to provide conversion factors between the relative scale of charcoal abundance and the absolute scale of fire. We show that pollen taxon abundance has good predictive power for fire (r2 = 0.56) and that the contribution of specific taxa to the prediction makes sense in terms of their ecological adaptations to fire. We apply the TWA-PLS quantitative relationship to predict changing fire regimes across the Iberian Peninsula through the Holocene. Results show that fire change synchronous with climate warming events.
Morphotectonic analysis along the northern margin of Samos Island, related to the seismic activity of October 2020, Aegean Sea, Greece
Authors: Nomikou Paraskevi , Evangelidis Dimitris , Papanikolaou Dimitris , Lampridou Danai , Litsas Dimitris , Tsaparas Giannis , Koliopanos Ilias
Published: March 2021

On October 30th 2020 a strong earthquake of magnitude 7.0 occurred north of Samos Island at the Eastern Aegean Sea. This seismic event was another destructive active deformation in the long seismic history of Samos since the ancient times. Preliminary reports focused the seismic epicenter at about 10 km north of Karlovassi, situated at the western part of the Samos E-W trending coastline. The earthquake mechanism corresponds to an E-W normal fault dipping to the north. The activated fault was assumed to be running along the northern margin of Samos Island, which bounds from the south the Samos basin.

Immediately after the seismic activity and during the aftershock period in December 2020 an hydrographic survey off the northern coastal margin of Samos Island was conducted with R/V NAUTILOS of the Hellenic Navy Hydrographic Service, using the multibeam SeaBat 7160 RESON. The result of the hydrographic survey was a detailed bathymetric map with 15m grid interval and 50m isobaths.  The main morphological aspects of Samos Basin are a 14 km long, 6 km wide and 690 m deep elongated E-W basin developed north of Samos Island.

The southern margin of the basin is abrupt with morphological slopes of more than 10o, following the major E-W normal fault surface, running along the coastal zone, with an overall throw of more than 500m. In contrast, the northern margin of the basin shows a gradual slope increase towards the south from 1o to 5o. Numerous small canyons trending N-S transversal to the main direction of the Samos coastline are observed along the southern margin, between 600 and 100 m water depth.  These canyons have a length around 2,7 km and width between 100-300 m. Two large submarine landslides with a canyon width of 1,3 km and 0,8 Km, are located north of Karlovasi. The creation of the canyons is probably due to the uplift of Northern Samos Island and their 500 m vertical height difference corresponds to the average fault throw that has controlled the steep slopes of the margin. The orientation of the fault scarp changes at the western Samos coastline from E-W to ENE-WSW facing the neighboring Ikaria Basin, which is developed to the west of Samos Basin. The division line between the Ikaria and Samos basins runs N-S from the northern slopes and coast of the Kerketeas mountain (1443m). The aftershocks of the 30th October main shock are limited east of the N-S division line with only a minor activity 15 km to the west within the eastern margin of the Ikaria Basin.
Using a socio-hydrology stance to address the paradox between global decarbonisation, lithium fever, and sustainability in the Atacama Salt Deposit
Authors: Canales Marcos , Castilla-Rho Juan , Vicuña Sebastian , Ball James , Filatova Tatiana
Published: March 2021

Climate-warming greenhouse gas emissions can be reduced by replacing petroleum-driven vehicles with electric vehicles powered by rechargeable lithium batteries. By 2025, 45% of the world’s Lithium will be sourced from water-intensive mining operations adjacent to fragile eco-hydrological systems in the Atacama Desert, the world’s driest desert. In the remote Atacama salt flat basin, home to one of the world’s richest deposits of high-grade lithium, brines are being mined from aquifers, with potential impacts on the long-term environmental, ecological, economic, and social viability of the system. Stakeholders (scientists, communities, and decision-makers) are currently entrenched in adversarial relationships and top-down policy-making and implementation.

A socio-hydrology stance considering telecoupled systems of people and water is essential to address the paradox between the quest for global decarbonisation and unsustainable use of water resources in the Atacama region. The inclusion of social drivers (beliefs, biases, values, and heuristics), however, adds complexity to the analysis. To address this complexity, novel methodologies such as participatory modeling (PM) and agent-based modeling (ABM) can be implemented. The former can enrich the system with specialist and local knowledge, increase the perceived utility of models, their credibility through transparent communication of the limitations and uncertainties, and the adoption and acceptance of the model results, which ultimately guide public policy. The latter seeks to represent explicitly the complexity and heterogeneity in these telecoupled systems.

The socio-hydrological problem at the Atacama salt flat is conceptualized using the Fuzzy-Logic Cognitive Mapping methodology through participatory workshops, involving scientists, regulators, and government officials. An ABM is then coupled to an integrated and regional groundwater-surface water model to better understand the impacts of management scenarios and social interactions, and their feedbacks on the eco-hydrological system. Ultimately, the aim of this research is to take a socio-hydrology stance to analyze a wicked problem with social, environmental, and economic implications at the local and global scales, and in doing so, expand fundamental knowledge of socio-hydrology.
Chronology and Element Distribution of Shock-deformed Regions in Zircon from the Chicxulub Impact Structure
Authors: Jiawei Zhao , Long Xiao , Qi He , Zhiyong Xiao
Published: March 2021

Zircon is ubiquitously used to nail down the geological events for both terrestrial and extraterrestrial materials. The U-Pb system and other trace elements in zircon plausibly remain stable and robust in normal metamorphic processes on Earth, while under the extremely shock condition, trace element behaviors in zircon could be unstable and differential due to the generated extraordinary deformations and thermal annealing. Since the systematic deformations in zircon recovered from the Chicxulub impact structure, such as planar fractures (PFs), reidite and granular zircon, the phenomenon of partially or completely age resetting are discovered in zircons from impact melt, breccia, ejecta and meteorites. In effect, element migration during the shock or post-shock setting is the most critical question, which may yield age resetting in nature. The enrichment of elements in shock-deformed zircon regions (PFs and reidite) are revealed, such as Y, Al, Ca, U, Th and Pb. Due to the limitation of resolution and lack of typical shock deformations, the straightforward correlations among deformations, element migration and chronology in zircon by traditional means have not been illustrated clearly so far. Here we systematically analyzed the correlations between shock deformations (from low to high degree: PFs, reidite and granular zircon) and element distribution in zircon by high-resolution Nano-SIMS mapping data. This can be used to interpret the chronology of shock products both from terrestrial and extraterrestrial bodies.
Identifying the sources of seasonal potential predictability using Fractional Integral Statistical Model with a Variance Decomposition Method
Authors: Nian Da , Yuan Naiming , Ying Kairan , Liu Ge , Fu Zuntao , Qi Yanjun , Franzke Christian L. E.
Published: March 2021

It is well recognized that climate predictability has three origins: (i)climate memory (inertia of the climate system) that accumulated from the historical conditions, (ii) responses to external forcings, and (iii) dynamical interactions of multiple processes in the climate system. However, how to systematically identify these predictable sources is still an open question. Here, we combine a recently developed Fractional Integral Statistical Model (FISM) with a Variance Decomposition Method (VDM), to systematically estimate the potential sources of predictability. With FISM, one can extract the memory component from the considered variable. For the residual parts, VDM can then be applied to extract the slow varying covariance matrix, which contains signals related to external forcings and dynamical interactions of multiple processes in climate. To show the improvement of our methodology, we have tested it on realistic data, using monthly temperature observations over China during 1960-2017.  It is found that the climate memory component contributes a large portion of the seasonal predictability in the temperature records. Our results offer the potential for more skillful seasonal predictions compared with the results obtained using FISM or VDM alone.