bluuebunny/crossref_metadata_2025 huggingface dataset:
Probing the micromechanical features of a fracture interface using a multi-physics approach: A numerical investigation relating asperity deformation with fluid flow
Authors: Wood Clay , Ke Chun-Yu , Rathbun Andy , Riviere Jacques , Elsworth Derek , Marone Chris , Shokouhi Parisa
Published: March 2022

The focus of this study is to elucidate the relation between elastodynamic and hydraulic properties of fractured rock subjected to local stress perturbations in relation to fracture aperture distribution. The goal of our integrated numerical and experimental investigations is to understand the mechanisms responsible for changes in fault zone permeability and elasticity in response to dynamic stressing in the subsurface (anthropogenic or seismic in origin). High-resolution (micron-scale) optical profilometry measurements combined with pressure sensitive films have been used to characterize fracture properties such as ‘true’ contact area, aperture distribution and morphology, as well as asperity deformation under applied loads in our experiments. These measurements allow a direct correlation between fracture properties and our lab measurements of fracture elastic nonlinearity and permeability. Using micron-resolution profilometry of centimeter-scale samples, we calculate the elastic deformation of fracture asperities to varying applied  stresses (static and dynamic) using Hertzian contact mechanics. Then, permeability is calculated for each applied stress (deformed asperities) using the parallel plate approximation, in which the Reynolds equation is solved using the finite difference method. This study is uniquely constrained, wherein we investigate the effect of measured deformation of real asperities on creating flow pathways through a fracture. Future work will include implementing contact acoustic nonlinearity (CAN) to model the change in transmission of acoustic waves across the fracture interface during stress perturbation.
Influence of Particle Sizes on Solute and Heat Transport Interpretation
Authors: Baek Ji-Young , Park Byeong-Hak , Lee Kang-Kun
Published: March 2022

Tracer experiments have been carried out for various scales to enhance the understanding of transport processes in porous media. The comparison between multi-tracers behaviors could provide insights in using tracers for the aquifer characterization. Especially, the comparison of heat and solute transports has been drawing attention in recent studies based on the similarity of governing equations. However, the difference between influences of particle sizes on heat and solute transport processes has yet to be clarified. In this study, to investigate the impacts of mean grain size (d50) difference on solute and heat transports, laboratory heat, and solute tracer experiments were conducted using two grain sizes of sand (d50 = 0.50, and 0.76 mm). Obtained experimental data were analyzed by mathematical models and those results were compared at 7 different flow conditions for two different mean grain sizes. Compared to other experimental data conducted with various particle sizes, normalized thermal dispersion coefficients showed a wider range of values to the different particle sizes under the same Pèclet number than normalized solute dispersion coefficients, even though the heat transport occurred in smaller Pèclet numbers. These results could indicate that the influence of particle size difference could be more critical in thermal dispersion coefficients.

Acknowledgements

This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No. 2017R1A2B3002119). This work was also supported by Korea Environment Industry & Technology Institute(KEITI) through "Activation of remediation technologies by application of multiple tracing techniques for remediation of groundwater in fractured rocks" funded by Korea Ministry of Environment (MOE)(Grant number:20210024800002/1485017890). This work was also supported by the Institute for Korea Spent Nuclear Fuel (iKSNF) and National Research Foundation of Korea (NRF) grant funded by the Korean government (Ministry of Science and ICT, MSIT) (Grant number: 2021M2E1A1085200).

 
Anthropogenic and precipitation factors affecting karst soil erosion in the Nandong Underground River System in Yunnan, Southwest China
Authors: Li yanqing , Yue xiangfei , Liu peng , Lan funing , Yu yang
Published: March 2022

In  karst areas, underground riverine sediment has been widely used to reflect the subterranean stream basin erosion, which influenced by both of precipitation and anthropogenic factors. In this study, 15-years of the sediment yield across Nandong underground river system of China were monitored, Mann-Kendal mutation test and simple proxy indicators were used for detecting the influences of human activities and precititation on sediment yield. The results showed that: 1) both of the anthropologic factor and rainfall impacted sediment yield, although the influence of anthropologic factor on sediment yield was greater (76.38%), and 2) rainfall showed a hysteresis effect on soil and water loss. There were three distinct stages based on the mutation points and variation characteristics of sediment yield from 1998 to 2014, resulting from different driving forces. Before 2004, the decease of sediment yield was caused by natural forest protection project in the whole basin. During 2004 to 2008, because of drought, flood disaster and cultivation on steeper slope, sediment yield of the basin increased. After 2009, sediment yield decreases due to the construction of soil conservation projects and mushrooming reservoirs. As human population is expected to increase, these findings are expected to provide insights for watershed management and ecological restoration in the fragile karst ecosystem.
Contribution of cross-equatorial dry intrusions to Indian summer monsoon rainfall
Authors: Rai Deepika , Raveh-Rubin Shira
Published: March 2022

Daily-to-weekly variations between active and break monsoon phases critically control Indian summer monsoon (ISM) rainfall and directly influence society. This variability depends on the complex air flows from different origins; for example, dry intrusions (DIs) reaching the Indian region from western Asia limit ISM rainfall. This study documents DIs that originate in the southern hemisphere winter, cross the equator and reach the Arabian Sea during the ISM season. Being a global hot spot of such cross-equatorial intrusions, they have great potential to modify the moisture availability and hence the ISM rainfall.
Using 6-hourly ERA-Interim reanalysis data with a Lagrangian approach, we show that more than 95% of cross-equatorial DIs reach below 850 hPa in the Arabian Sea within five days of their initiation in the southern hemisphere. Though rare (<1% frequency in time), their presence in the marine boundary layer triggers intense ocean evaporation and enhances the low-level Somali jet intensity. The result is compensation for their initial dryness and overall increasing the moisture transport towards India. Analysis based on 130 DI events during the ISM season from 1979-2018, shows that more than 64% of the DI events are associated with more rainfall, with a mean 12% enhancement in the rain compared to climatology. These DI events favor the central Indian Ocean as the major source of moisture during the ISM season, different from mean conditions. Indeed, 52% of known active spells are preceded by DI events. In summary, cross-equatorial DIs reaching the marine boundary layer over the tropical Indian ocean during ISM season is responsible for the development of anomalously moist air, which enhances the rainfall over the Indian region downstream, and are thus crucial for ISM rainfall predictability.
Promoting and supporting gender dimension in the CCUS community – A novel approach by the C4U Project
Authors: Rebscher Dorothee , Catalanotti Elena , Mahgerefteh Haroun
Published: March 2022

The C4U Project, funded by the European Union H2020 programme, advances carbon capture for steel industries integrated in Carbon Capture, Utilisation, and Storage (CCUS) clusters. Besides working on the scientific and technological challenges, the project members are committed to integrate social aspects not only as part of their work but also by promoting an inclusive work ethics within the consortium itself. In this respect, actions have been taken on all levels and roles of the project as well as during all its steps to mitigate the imbalance in representation without negatively impacting aptitude or expertise.  In addition to raising awareness and furthering discussions among the C4U members, providing options for hiring processes, or adjusting speaker lists and the distribution of board roles, a novel approach was conceptualised in the form of an international workshop, as an initiative from within the CCUS community for the community, and hopefully beyond.

This first C4U workshop on gender dimension called "Woman in CCUS – Inspire and be inspired" was open to all associated with the field of CCUS and was held in fall 2021. As the free event took place virtually on two half days due to COVID restrictions, scientists, including students and managers, originating from or with affiliation of all continents, registered. Talks and breakout room sessions covered topics such as raise awareness of gender imbalance and ethical concerns, identify reasons behind the still existing inequality, search for countermeasures, the importance and consequence of confidence, as well as private and professional life experience, all with numerous opportunities for discussions. By expressively embracing all genders, career phases, ethnical or scientific backgrounds, we were able to achieve participation with a large diversity also in regard to work environment, e.g. academia, governmental agencies, and industry. Bringing people together using a virtual format and in numerous time zones naturally has its own challenges, especially when communicating on sensitive and personal topics. However, the overwhelming engagement of the participants during, but also already prior to the workshop, revealed that there is a significant need in the CCUS community for an open, personal exchange on gender related topics, by all genders. On this basis, the C4U initiative aims to be a seed for an inclusive platform, for a diverse network to get to know role models and at the same time be one oneself, to inspire and be inspired.
Preferential flow prediction—present and future 
Authors: Nimmo John R.
Published: March 2022

The generally accepted theory of unsaturated flow, encapsulated in the hundred-year-old Richardson-Richards equation (RRE), has been successful in many situations, especially for diffuse flow through homogeneous granular media with grains and pores of sand-size or smaller. Since the late twentieth century, some version of it has also been the most commonly applied predictor of preferential flow, typically in combination with the RRE in a dual-domain framework in which the parameters take different values in the two domains. Current knowledge of preferential flow processes, however, shows that this extension of its original use is inappropriate. Various alternative formulations have been developed for preferential flow, many of them based on film and wave concepts, but these also have limits on their applicability. They also can be prohibitively awkward to combine with RRE to account for the totality of flow in an unsaturated medium.

Given the different dominant processes of diffuse and preferential flow, the widely used dual-domain framework is appropriate. The RRE is available for flow in the diffuse domain, but improved methods are needed for the other two fundamental components: flow in the preferential domain, and the exchange of water between domains.

For the preferential domain, I suggest these concepts and guiding principles: (1) A flow-velocity parameterization that is generalized, not specifically tied to a particular geometrical form such as films. (2) Variability of volumetric flux that is independent of flow velocity, not inextricably linked to velocity as in the gravity term of the RRE. (3) Gravity is the only significant driving force. (4) The essential constancy and uniformity of gravitational force is a tremendous advantage, and with the absence of pure diffusive flow, it reduces the required variables to just two, flux and water content, as opposed to the triply-coupled water-content/matric-potential/conductivity variables in the RRE. Further consequences are that (a) the basic continuity equation is the central component of a partial differential equation operative within the preferential domain, and (b) flux boundary conditions are the only type possible for this domain. 

Some guidelines for domain exchange are: (1) Flow can go in either direction, seepage as well as abstraction, depending on the diffuse-domain water content. (2) The exchange can be represented as a first-order diffusion process, from the domain interface to an internal position within the diffuse domain; this requires an additional parameter representing the effective lateral distance that this introduced water travels within the diffuse domain.

A formulation based on these principles would require much development and testing, but if implemented with a minimal number of parameters, each of them having a physically meaningful interpretation, it could lead to a more versatile and acceptable way to predict preferential flow than is presently available.
Estimating nonlinear stability from time series data
Authors: van Kan Adrian , Jegminat Jannes , Donges Jonathan
Published: March 2022

Basin stability (BS) is a measure of nonlinear stability in multistable dynamical systems. BS has previously been estimated using Monte-Carlo simulations, which requires the explicit knowledge of a dynamical model. We discuss the requirements for estimating BS from time series data in the presence of strong perturbations, and illustrate our approach for two simple models of climate tipping elements: the Amazon rain forest and the thermohaline ocean circulation. We discuss the applicability of our method to observational data as constrained by the relevant time scales of total observation time, typical return time of perturbations and internal convergence time scale of the system of interest and other factors.
Self-supervised Automated Mineralogical and Chemical Analysis for Hyperspectral Datasets
Authors: Tung Po-Yen , Sheikh Hassan , Ball Matthew , Nabiei Farhang , Harrison Richard
Published: March 2022

Identification of unknown micro- and nano-sized mineral phases is commonly achieved by analysing chemical maps generated from hyperspectral datasets, particularly scanning electron microscope - energy dispersive X-ray spectroscopy (SEM-EDX). However, the accuracy and reliability are limited by subjective human interpretation and instrumental artefacts in the chemical maps. At the same time, machine learning has emerged as a powerful method to overcome the roadblocks. Here, we propose a self-supervised machine learning approach to not only identify unknown phases but also unmix the overlapped chemical signals of individual phases with no need for user expertise in mineralogy. This approach leverages the guidance of gaussian mixture modelling (GMM) clustering fitted on an informative latent space of pixel-wise elemental data points modelled using a neural network autoencoder, and deconvolutes the overlapped chemical signals of phases using non-negative matrix factorisation (NMF). We evaluate the reliability and the accuracy of the new approach using two hyperspectral EDX datasets. The first dataset was measured from an intentionally fabricated sample, where seven known mineral particles are physically overlapping with each other as well as the substrate. Without any prior knowledge, the proposed approach successfully identified all major phases and recovered the original chemical spectra of the individual phases with high accuracy. In the second case, the dataset was collected from a potential vehicular source of particulate matter air pollution, where identification of the individual pollution particles is complicated by the complex nature of the sample. The approach once again was able to identify the potential Fe-bearing ultrafine particles and isolate the background-subtracted elemental signal. We demonstrate a robust approach that potentially brings a significant improvement of mineralogical and chemical analysis in a fully automated manner. In addition, the proposed analysis process has been built into a user-friendly Python code with graphical user interface (GUI) for ease of use by general users.
Groundwater level prediction method using deep learning for evaluating a nature restoration project in Kushiro wetland, Japan
Authors: Yamaguchi Takumi , Miyamoto Hitoshi , Oishi Tetsuya
Published: March 2022

In this study, we developed a groundwater level prediction model using deep learning to evaluate a nature restoration project in Kushiro wetland. The accuracy of the model was verified and a method for analyzing the importance of model variables was proposed.

In the Kushiro wetland, the marshland was degraded by the straightening of the river channel in the past, and alder trees grew in abundance. In 2010, the river was re-meandered to its original meandering channel in order to restore the natural environment. The observation data of groundwater level time series were collected from this restoration area. In this study, we developed a deep learning model for the two periods before and after the restoration.

Long short-term memory (LSTM) was used as a deep learning model. In LSTM, the input layer contained six components as explanatory variables and groundwater level as an objective variable in three days, and the output layer predicted the groundwater level one day later. The six explanatory variables in the input layer were precipitation, air temperature, sunshine duration, snow depth, normalized difference vegetation index (NDVI) and river discharge. The accuracy of the models produced in the pre- and post- restoration periods was evaluated by the root mean squared error (RMSE) of the measured and predicted values. The results showed that the RMSE is 0.055m~0.162m, which indicated that the LSTM model can predict the groundwater level fluctuation characteristics accurately.

The importance analysis method proposed in this study was based on the Wrapper Method used in machine learning. This method (Applied Wrapper Method) was able to extract the most important variables from the explanatory variables if the its truncation caused a significant decrease in model accuracy. The results showed that the river flow discharge and precipitation had a significant effect on the groundwater level time series regardless of whether it was before or after the restoration.

The groundwater level prediction model based on the deep learning proposed in this study was confirmed to predict the groundwater level fluctuation characteristics in Kushiro wetland with good accuracy by providing important natural factors. In the future, we plan to incorporate the topography and soil properties of the wetland into the analysis to evaluate the effect of the nature restoration project more accurately.
Impact of rainfall intensity on GRACE total water storage across Australia
Authors: Shadmehri Toosi Amirhossein , Batelaan Okke , Shanafield Margaret , Guan Huade
Published: March 2022

Climate change has a significant impact on the environment by increasing the frequency of extreme precipitation events. Underestimating the potential risks of such events and lack of climate resilience will result in a substantial crisis in terms of water security. Understanding the hydrological consequences is difficult due to complexities and additional environmental feedbacks, depending on landuse/landcover, soil and climate.

The Gravity Recovery and Climate Experiment (GRACE) has provided an unprecedented perspective on global fluctuations in terrestrial water storage (TWS) over the past decade. While numerous studies have correlated different hydrological variables against TWS, no study has tested different rainfall thresholds (intensity) impacting TWS. Existing studies mostly have explored the relationship between TWS anomalies and hydrological variables using individual responses, while few have looked at multi-variable interaction. Single indicators (e.g., standardized precipitation index) may limit ecohydrological understanding of soil-vegetation-atmosphere water transfer, as many factors play essential roles in land-atmosphere interactions. In particular, rainfall characteristics can significantly impact the interaction between hydrological factors by accelerating or slowing processes. Hence, including appropriate temporal resolution of precipitation in analyses is essential; e.g., monthly data are not a good indicator for understanding ecohydrological interactions. Therefore, this research aims to improve our understanding of the spatiotemporal response of TWS to climate change impacts on rainfall characteristics. Monthly GRACE TWS time series anomalies are analyzed against aggregated monthly rainfall with different daily thresholds (intensities). The obtained results are used to find explanatory variables such as land use/land cover, soil type, and climatic zones that determine the significance between TWS and various variables. The methodology provides a valuable insight into the mechanisms in which TWS is affected by rainfall characteristics at different spatiotemporal scales across various hydrological contexts across Australia.
Using a Hydrological Model to Understand the Hydrological Processes in a Mosaic Tropical Peatland Landscape of Pulau Padang, Indonesia
Authors: Asyhari Adibtya , Kurnianto Sofyan , Suardiwerianto Yogi , Hidayat Muhammad Fikky , Harahap Mhd. Iman Faisal , Evans Chris , Page Susan , Agus Fahmuddin , Astiani Dwi , Sabiham Supiandi , Mezbahuddin Symon , Balamurugan Murugesan , Ghimire Chandra Prasad , Deshmukh Chandra Shekhar
Published: March 2022

Tropical peatlands play an important role in addressing the climate and nature functions. In these ecosystems, hydrology strongly controls their geomorphology, ecology, and carbon cycle. More frequent and severe droughts driven by climate extremes (e.g. El Niño Southern Oscillation and the Indian Ocean Dipole events) may alter their local hydrology. In addition, growing dependencies on tropical peatlands due to population growth and economic development has resulted in land-cover change. Alteration in the hydrological processes under changing climate and land-cover may have crucial implications on tropical peatlands, but such impacts remain poorly understood.

In this context, we used a coupled MIKE SHE and MIKE Hydro River model to represent the hydrological processes within Pulau Padang (~1,100 km2), a peat-dominated island in the eastern coast of Sumatra, Indonesia. The island is a mosaic landscape of peat swamp forest, smallholder area, and industrial plantation. We collected a comprehensive vegetation and peat properties data from field measurements, supported by high-resolution digital terrain model derived from airborne LiDAR, for the model setup. We calibrated and validated the model against observed groundwater level and stream flow data distributed across the island. Finally, we also evaluated the impacts of land-cover change trajectory in the island by comparing the water balance components (i.e. evapotranspiration, runoff, and storage change) for different hydroclimatic extremes (i.e. El Niño and La Nina) under its current condition (baseline year of 2016) to that of its past (25-year look back period) and future (50-year trajectory) conditions.

This research should contribute to advance the understanding of the landscape scale hydrological processes in tropical peatlands under land-cover change trajectory, which are important to provide scientific basis for stakeholders involved in guiding responsible peatland management practices. This presentation will discuss the modeling approach and preliminary results.
Numerical simulations of an internal solitary wave evolution beneath an ice keel
Authors: Zhang Peiwen , Xu zhenhua , Li qun , You jia , Yin baoshu , Robertson robin , Zheng quanan
Published: March 2022

The deformation and evolution of internal solitary waves (ISWs) beneath an ice keel can enable potential diapycnal mixing and facilitate upper ocean heat transport, despite a poor understanding of the underlying physics and energetics of ISWs in Polar environments. This study aims to understand the dynamic processes and mixing properties during the evolution of ISWs beneath ice keels (undersea portion of ice cover) in the Arctic Ocean using high-resolution, non-hydrostatic simulations. Ice keels can destabilize ISWs through overturning events. Consequently, the initial ISW disintegrates and transfers its energy into secondary smaller-scale waves. During the ISW-ice interaction, ISW-induced turbulent mixing can reach O(10-3) W/kg with a magnitude of resultant heat flux of O(10)W/m. Sensitivity experiments demonstrated that the ISW-ice interaction weakened as the ice keel depth decreased, and consequently, the resultant turbulent mixing and upward heat transfer also decreased. The ice keel depth was critical to the evolution and disintegration of an ISW beneath the ice keel, while the approximate ice keel shape had little effect. Our results provide an important but previously overlooked energy source for upper ocean heat transport in the Arctic Ocean.
Soil erosion of sediment sources and their impact factors in a check dam control watershed on the Loess Plateau of China
Authors: Bai Lulu , Shi Peng
Published: March 2022

Quantitative analysis of sediment sources is crucial for soil and water conservation. For instance, composite fingerprint identification technology is widely used to study sediment sources in small dam-controlled watersheds, but its use in historical reconstructions of soil erosion in sediment source areas is uncommon. As soil erosion is a major issue in some areas of China, we propose the combination of flood couplet construction with the fingerprint method to estimate soil erosion in sediment source areas of a typical check dam on the Loess Plateau, which is known for its severe soil erosion. A flood couplet, based on the activity of 137Cs in the sediment, was constructed, and the historic soil erosion was calculated using soil bulk density and storage capacity curves. The contribution rate of the sediment sources was calculated by using the fingerprint method, and the amount of erosion in the sediment source areas was estimated. We found 29 flood events (1956–1990); the total sediment volume was approximately 56121 m3, and the sediment yield was approximately 77430 t. The best fingerprint combination (Cr, Ni, V, and TOC) allowed to a 97.2% the recognition of the sediment sources. The contribution rates of ditches, cultivated land, grassland, and shrub land were 44.89%, 26.38%, 10.49%, and 18.24%, respectively. Meanwhile, the average sediment yield of ditches, farmland, grassland, and shrub land were 1227, 751, 512, and 279 t, respectively. These results provide an effective scientific basis for the rational allocation of soil and water conservation measures in small watersheds.
Intensifying hydrologic drought in California
Authors: Argus Donald , Martens Hilary , Borsa Adrian , Wiese David , Knappe Ellen , Larochelle Stacy , Anderson Mackenzie , Peidou Athina , Khatiwada Ashlesha , Lau Nicholas , White Alissa , Hoylman Zachary , Swarr Matthew , Cao Qian , Pan Ming , Chanard Kristel , Avouac Jean-Philippe , Payton Gardner , Landerer Felix
Published: March 2022

Drought has struck the southwest U.S. for the fourth time this millennium, reducing freshwater available to agriculture and urban centers.  We are bringing new insight by quantifying change in water in the ground using GPS elastic displacements, GRACE gravity, artificial reservoir levels, and snow models. Precipitation in Water Year 2021 was half of normal; the rise in total water in autumn and winter is 1/3 of the seasonal average (estimated using chiefly GPS); water was parched from the ground in the spring and summer, bringing water in the ground to its historic low (estimated using primarily GRACE).  In the Central Valley, soil moisture plus groundwater each year increases by 11 km3 and is maximum in April.  Only half of groundwater lost during periods of drought is replenished in subsequent years of heavy precipitation.  The Central Valley has lost groundwater at 2 km3/year from 2006 to 2021, with 2/3 of the loss coming from the southern Valley.
Nonlinear damped higher order nonlinear Schrodinger dynamics
Authors: Schober Constance
Published: March 2022

 The spatially periodic breather solutions (SPBs)  of the nonlinear Schr\"odinger equation, prominent in modeling rogue waves, are
  unstable.
 In this paper we numerically investigate the effects of nonlinear dissipation and higher order nonlinearities  on the routes to stability of the SPBs in the 
framework of the nonlinear damped higher order nonlinear Schr\"odinger (NLD-HONLS) equation. 
We appeal to the  Floquet spectral theory of the NLS equation to interpret and provide a characterization of the perturbed dynamics in terms of nearby solutions of the NLS equation. The number of instabilities of the background Stokes wave, the damping strength, and the time of onset of  nonlinear damping  are varied. 
A broad categorization of the routes to stability of the SPBs and the novel features related to the effects of nonlinear damping will be discussed.
Diverse responses of semi-arid grasslands to severe droughts in Inner Mongolia, China
Authors: Li Xiran , Hajek Olivia
Published: March 2022

Covering almost one-third of the land, grasslands play an important role in providing ecosystem functions and services such as carbon cycling. Further, grasslands are considered to be one of the ecosystems most sensitive to drought. As the frequency and intensity of droughts increase globally with climate change, it is urgent to quantify the characteristics and mechanisms of grassland responses to drought events.    
In this study, we studied the response of grassland growth to drought events in the semi-arid grasslands of Inner Mongolia, China. This semi-arid grassland is characteristic of many grasslands globally, such as in the entire Eurasian steppe belt. By utilizing remote sensing data (MOD13A1), gridded climate data interpolated from weather station observations (CRU TS4.03), and drought index calculated from the CRU datasets (SPEI03 from SPEI database) at 500m*500m spatial resolution, we found that the semi-arid grasslands in our study area experienced severe droughts in the summers (June, July, and August) of 2007 (SPEI03min = -1.94) and 2017 (SPEI03min = -2.37). Surprisingly, in 2017, the grasslands appeared to be almost unaffected by the extreme drought (EVIano = 0.004), while in 2007, productivity was reduced during drought (EVIano = -0.026). 
To explore why the semi-arid grasslands responded differently to these two summer drought events, partial correlation analysis was done by considering the influence of temperature, precipitation, and SPEI03 on EVI in summer during 2001-2018. The results showed that grasslands are generally significantly correlated to SPEI03 (39.73% pixels with p<0.1) rather than to temperature (13.27% pixels with p<0.1) or to precipitation (11.39% pixels with p<0.1).  However, when we compare the spatial distributions of EVI, temperature, precipitation, and SPEI in summer in 2007 and 2017, a different pattern emerges. Temperature patterns were similar between summer in 2007 and 2017, but precipitation patterns were different, resulting in different SPEI patterns. In regions which showed a significant, positive correlation with precipitation, there was heavier rainfall (100mm/month<precipitation<140mm/month) in 2017 than in 2007 (precipitation<100mm/month). The heavy rains offset the negative effect of heatwave, and enhanced grass productivity in areas with moderate temperature in summer in 2017. These results demonstrate the importance of monthly to seasonal precipitation patterns and provide a reference for management in response to extreme drought events in semi-arid grassland ecosystems.
Mapping socio-ecological vulnerability of tropical peat landscape fires
Authors: Lee Janice Ser Huay , Fatimah Yuti Ariani , Smith Stuart William , Rahman Nur Estya , Nurhidayah Laely , Wardhana Budi , Saad Asmadi , Prasojo Zaenuddin , Khan Feroz , Wu Maple Sifeng , Giam Xingli , Chong Kwek Yan , Graham Laura , Lallemant David
Published: March 2022

Fire represents a mainstay for rural communities managing tropical landscapes. However, increasing uncontrolled fires in tropical landscapes because of land use and climate change pose a major threat to livelihoods, public health, and ecosystems. Peatlands in Southeast Asia are one such example of tropical landscapes that experience high flammability due to clearance of forests and excessive drainage for agriculture and forestry. The degradation of tropical peatland ecosystems increases their susceptibility to landscapes fires, which in turn increase the vulnerability of people and peatland conditions to future fires. To identify locations of tropical peatlands and surrounding communities that are vulnerable to fires, we conducted a socio-ecological vulnerability assessment and mapped the socio-ecological vulnerability of tropical peatlands to fires. We used an inductive approach to conceptualize and operationalize vulnerability and its associated dimensions of exposure, sensitivity, and adaptive capacity through empirical case studies in the literature, with a focus on tropical peatlands and fires in Indonesia. We present preliminary results of our mapped social and ecological vulnerability of Indonesia’s tropical peatlands to peat landscape fires. This would allow policymakers to identify places which display both high ecological and social vulnerability to fires and channel aid and mitigation efforts where they are most urgently needed.
Postdepositional Controls on Fossil Body Size Distributions
Authors: Hohmann Niklas , Buchwald Stella , Korn Dieter , Klug Christian , De Baets Kenneth , Jarochowska Emilia
Published: March 2022

Animal body size provides information about the trophic position and reproductive strategies of species, and the presence of environmental stressors. The distribution of body sizes in fossils can be easily measured, making it an important tool for paleoecological studies. However, preservational and collection biases might influence the primary measurements and thus the results. Intuitively, smaller specimens of the same species should be more prone to destructive processes such as fracturing and dissolution. It is often assumed that body size distributions in death assemblages reflect those in living populations. We test this assumption.
Using the body size distributions in monospecific assemblages of Devonian ammonoids, we show that common depositional environments yield distinct distributions of conch sizes. We then simulate postdepositional conditions in recent analogues of these environments. If conch size is proportional to robustness (or disintegration rate), sedimentation rates and mixing intensities characterizing these recent analogues allow us to reconstruct conch size distributions observed in Devonian counterparts of these environments.
The results show that shape parameters of body size distributions (skewness and kurtosis) are modified in predictable ways in sedimentary environments. This implies that fossil body size distributions are not a direct reflection of ecological signals, but can be altered by postdepositional processes. We conclude that parameters of body size distributions, such as mean and dispersion, may not be comparable with parameters in standing populations. If changes in these parameters coincide with changes in the depositional environment, the effect of (post)depositional processes needs to be considered.
What are cratons?
Authors: Pearson Graham
Published: March 2022

The term craton has a complex and confused etymology. Despite originally specifying only strength and stability – of the crust – the term craton has seen widespread use as referring to a region characterised by crustal basement older than 2.5 Ga, despite the fact that some such “cratons” no longer possess their deep lithospheric root and have geological histories that contnue well beyond the Archean/Proterozoic boundary.  Viscous, buoyant lithospheric mantle roots are key to the survival and stability of continental crust. Here we use a revised craton definition (Pearson et al., 2021, Nature), that includes the requirement of a deep (~150 km or greater) and intact lithospheric root, to re-examine extent and character of regions defined as crtons. The revised definition has a nominal requirement for tectonic stability since ~ 1 Ga and recognises that some regions are “modified cratons” – having lost their deep roots, i.e., they may have behaved like cratons for an extended period but subsequently lost much of their stabilising mantle roots during major tectono-thermal events. In other words, despite being long-lived features, cratons are not all permanent. The 150 km lithospheric thickness cut-off provides an optimal match to crustal terranes with 1 Ga timescale stability.

We examine the processes involved in craton ormation and growth. Seismology can help to define the lateral extent of today’s cratons, but a detailed understanding of the regional geological history, kimberlite eruption ages and geothermal conditions is required to evaluate periods of past diamond potential, no-longer evident today. 
Coupled impact of proteins with different molecular weight and surface charge on nanoparticle mobility
Authors: Shang Jianying , Yan Chaorui , Sharma Prabhakar
Published: March 2022

The widely present proteins in the natural environment interact with the released nanoparticles, which change the stability, transport, and fate of nanoparticles. Since proteins with different molecular weights contain various amino acids, the surface properties of the protein are different, and the mechanisms that affect the stability and mobility of nanoparticles are also distinct. Until now, the effects of proteins with different molecular weights and surface charges on nanoparticles have received little attention. In this study, the effects of concentrations and three different molecular weights of protein on the stability and mobility of TiO2 nanoparticles are investigated. Our study found that with the increase in bovine serum albumin (BSA) concentration from 2 to 16 mg L-1, the capacity of the BSA adsorption on the TiO2 surface increased from 37 to 85 mg g-1, and the thickness of the BSA adsorption layer increased from 4.7 to 5.8 nm, causing stronger steric repulsive interaction. When the proteins had similar negative surface charge, the molecular weight decreased from 68 to 14 kDa, the capacity of the protein adsorption on the TiO2 surface increased from dozens to more than 100 mg g-1, and the thickness of the protein adsorption layer increased from 5.4 to 7.5 nm, resulting in stronger steric repulsion. For the proteins with different molecular weights and negative surface charges, the thickness of the protein adsorption layer is the dominant factor for TiO2 stability, and both the steric and electrostatic repulsion played the critical role in TiO2 mobility. This study emphasized that the steric repulsion induced by the thickness of the protein adsorption layer increased nanoparticle stability in aqueous environment, and the coupled impact of steric and electrostatic repulsion due to different molecular weights and negative surface charges of proteins strongly affects nanoparticle mobility in saturated porous media.
Early hominins were variability avoiders and diversity seekers
Authors: Zeller Elke , Timmermann Axel , Yun Kyung-Soon , Raia Pasqual
Published: March 2022

Climate influenced the evolution of hominins, though the mechanisms and scales are still not well understood. We know that long-term climatic variations, such as wet-dry climate cycles and sea-level change, can change landscapes dramatically. Changes in landscapes can drive early hominins to find different locations to settle, but what kind of environments did they prefer and what role did changing climates play in all this? To research this question, we modeled the climate of the past 3 million years using CESM, made a best estimate of the global biome landscape, and compared the results to an extensive archeological database of hominin findings.

This analysis shows us that early hominins living in Africa predominantly lived in open habitats. When hominins expanded northwards, they adapted to more forested landscapes. While they were able to adapt, most hominin locations were found in areas with less variability and higher local biome diversity, suggesting that hominins prefer stable environmental conditions with a variety of resources nearby. This preference for stability and a landscape that offers diverse biomes is seen for all hominins regardless of species.
Increasing water-use efficiency mediates effects of atmospheric carbon, sulfur, and nitrogen on growth variability of central European conifers
Authors: Treml Vaclav , Tumajer Jan , Jandova Katerina , Oulehle Filip , Rydval Milos , Cada Vojtech , Treydte Kerstin , Masek Jiri , Vondrovicova Lenka , Lhotakova Zuzana , Svoboda Miroslav
Published: March 2022

Climate controls forest biomass production through direct effects on cambial activity and indirectly through interactions with CO2, air pollution, and nutrients availability. Atmospheric concentration of CO2 and sulfur or nitrogen deposition could exert a robust indirect control on wood formation, since they influence the stomatal regulation of transpiration and carbon uptake, that is, intrinsic water use efficiency (iWUE). Here we provide 120-year long time series of iWUE, tree growth, climatic and sulfur and nitrogen(SN) deposition trends for two widespread tree species, Pinus sylvestris (PISY) and Picea abies (PCAB), at their lower and upper distribution margins in Central Europe. The main goals were to explain iWUE trends using theoretical scenarios and climatic and SN deposition data and to assess the contribution of climate and iWUE to the observed growth trends. Our results show that after a notable increase in iWUE between the 1950s and 1980s, the positive trend slowed down. Substantial rise of iWUE since the 1950s resulted from a combination of an accelerated increase in atmospheric CO2 (Ca) and a stable level of leaf CO2 (Ci). The offset of observed iWUE values from the trajectory of iWUE growth proportional to increase in Ca (constant Ci/Ca scenario) was explained by trends in SN deposition (all sites) together with the variation of drought conditions (low-elevation sites only). Increasing iWUE over the 20th and 21st century improved tree growth at low-elevation drought-limited sites. In contrast to low-elevation sites, recent warming was the main reason for the growth increase at high-elevation PCAB. We propose that SN pollution should be considered to explain the steep increases in iWUE of conifers in the 20th century in a broader area of Central Europe and in other regions with a significant SN deposition history.
Detecting infiltration pathways by means of multi-method geophysical interpretation: an urban case study
Authors: Gallistl Jakob , Bano Georg , Schlögel Ingrid
Published: March 2022

Engineering-geophysical tasks in urban environments pose significant challenges for both the collection and interpretation of geophysical data. Typical problems that arise consist of background noise affecting seismic methods (i.e., moving cars or pedestrians), electromagnetic fields due to power lines and other infrastructure distorting electrical and electromagnetic methods and even traffic itself, requiring a thorough planning of fieldwork in order to minimize interruptions. To mitigate such limitations, commonly a combination of several geophysical methods is applied to counterbalance the caused distortions by a careful analysis of the data and combined modelling of the available information. Following this notion, we present a case study conducted in an urban setting in the first district of Vienna, a busy place in terms of both traffic and number of pedestrians. The objective was to delineate possible infiltration pathways of surface water or shallow subsurface water, infiltrating into an ancient cellar complex with a delay of two days after rainfall. The geophysical imaging included seismic refraction (RST) and multichannel analysis of surface waves (MASW), complex conductivity imaging (CCI) and ground-penetrating radar (GPR) measurements to characterize the subsurface architecture below the street (i.e., above the cellar) and CCI and GPR from within the cellar along the outer wall (i.e., below the street). Based on a combined analysis of the datasets from the street and the cellar itself, and incorporating 3D information from LiDAR within the cellar, we propose a model of infiltration pathways, as well as zones in the cellar wall possibly already strongly weakened by continuous high soil moisture.

 

 
Facies and environmental controls on dating carbonates using LA-ICP-MS
Authors: Cantine Marjorie , Gerdes Axel
Published: March 2022

Carbonates make up about one-quarter of Earth’s sedimentary record, and contain valuable biogeochemical records used to reconstruct Earth history. In situ U-Pb dating of carbonates using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) offers the possibility of dating these records directly, as well as deposition, diagenesis, and deformation. To fully assess the potential of this technique, laser ablation ages must be compared with other geochronological constraints. Geochemical (e.g., stable isotopes or trace elements) and petrographic context provide further guidance in the measurement and interpretation of carbonate-derived dates. This contribution presents case studies from our ongoing work, spanning Proterozoic and Phanerozoic samples from the marine realm, including the Neoproterozoic of Oman and Svalbard and the Cambro-Ordovician of North America. We highlight measured dates and with special focus on dating deposition and early diagenesis and integrating petrographic and geochemical data. We highlight the role of microbial mats and early marine cements in creating “datable” carbonates and discuss implications for sampling.    
Topographic analysis of debris flow gullies affected by tectonic activities on the edge of Qinghai-Tibet Plateau
Authors: Liang Xinyue , Ge Yonggang , Xu Mengzhen , Lyu Liqun
Published: March 2022

The collision between the Indian and the Eurasian Plates make crustal deformation and develop many faults of the Qinghai-Tibet Plateau. Debris flows affected by tectonic activities occur frequently and are various types on the edge of plateau. It is essential to scientifically categorize the debris flow gullies on active fault to understand their mechanisms, prevent and mitigate debris flow disasters. The tectonic landforms are the foundation for debris flows occurrence. Topographical measurements and statistical analyses of seven basins on the edge of the Qinghai-Tibet Plateau were carried out (Yarlung Zangbo River, Nu River, Indus River, Gaizi River, Bailong River, Xiaojiang River and Daheba River), in which typical debris flow gullies were concentrated. The results showed that debris flows were mainly distributed in the most active tectonic uplift zone of seven basins. The debris flow gullies were classified into three types by means of nonmetric multidimensional scaling. Type I was formed by rainstorms in exposed bedrock areas, Type II was formed by glaciers in exposed bedrock areas, and Type III was formed by rainstorms in depositional basins. Based on entropy method and fuzzy mathematics, the susceptibility of debris flow on seven watersheds was analyzed. Type I had good sediment connectivity due to rainstorms and main-river incision, and was easy to form small and middle-scale debris flow. Type II was easy to form high-frequency, middle and large-scale debris flows caused by abundant moraine deposit and good sediment transport under the glacier erosion. Type III was prone to form high-frequency and small-scale debris flows triggered by rainfall and loose depositional materials.