bluuebunny/crossref_metadata_2025 huggingface dataset:
Geohazard and Climate adaption:  impacts and interconnectivity
Authors: Ouzounov Dimitar , Kafatos Menas , Taylor Patrick
Published: March 2021

The forefront of science now is in bridging fields and making connections across different disciplines, challenging our current understanding of the Earth's changes and overall state. Some of the most challenging science questions now have to do with warnings for significant geohazards and Earth-Space systems' response to climate variability affecting adaptation processes, such as geosphere changes due to climate change and resultant strategies. In recent years, the study of pre-earthquake processes has led for example to developing the lithosphere-atmosphere-ionosphere-coupling concept. This in turn provides new information about the Earth's energy balance (Pulinets and Ouzounov, 2011). From space-born NASA and NOAA Earth observation of atmospheric conditions, we have shown the consistent occurrence of radiative emission anomalies in the atmosphere near or over regions of earthquakes, volcanoes, and geothermal fluxes. Our assessment shows that the latent heat released before major earthquakes is larger than the seismic energy released during the quake (Ouzounov et al., 2018). We find that the associated pre-earthquake phenomena for large events may create an additional thermodynamic contribution in the atmosphere and impact on climate, caused by sources of Earth de-gassing in the lithosphere and followed by ionization processes. Because of these findings, we start exploring major global geodynamics activities and their impact on atmospheric processes and climate through the geosphere coupling channels as a potential forward process of interaction between geohazards and climate adaptation. The reverse mechanism of climate adaptation's impact on geohazards is based on the initial idea that climate adaptation could force additional geohazards activities (McGuire, 2010). The removal of ice sheets may somehow or likely have permitted the release of stresses that had accumulated on previously confined faults, triggering earthquakes in the US, Canada, and Europe. How realistically is it to expect a change in the existing earthquake patterns in Europe, the USA, and Canada during climate change processes? It is plausible, but we do not yet know the answer. Our goal is to explore the coupling between geohazards processes and climate change processes through the lithosphere-atmosphere framework, focusing on dynamic environments, exhibiting a change in physical and thermodynamics processes over relatively small-time scales.
Capabilities and Applications of MACS Aerial Camera Systems for Environmental Research
Authors: Brauchle Joerg , Bucher Tilman , Hein Daniel , Berger Ralf , Gessner Matthias , Stebner Karsten
Published: March 2021

High resolution remote sensing under harsh environmental condition on special carriers requires instruments which are more flexible und more ruggedized than devices off the shelf. Particularly addressing environmental research in polar and high alpine regions, a family of cameras developed by the DLR is presented. The MACS systems are specifically made for the use on airborne platforms. Due to scalability, small sensors like single sensors on rugged fixed-wing UAVs can be realized. The configuration can be extended to RGB/NIR/TIR oblique viewing rigs with up to 5 coordinated cameras on manned aircraft. By processing such images, photogrammetric products like change detection, classification, elevation models and mapping mosaics are derived for regional areas. Further applications are the evaluation of algorithms in the field of AI for spaceborne imagery or the investigation of acquiring a particular combination of spectral bands.

These systems are able to deal with extreme illumination conditions and flight envelopes. Based on recent projects, the presentation shows examples and experiences, such as acquisition of the world’s highest glacier in Nepal, thermal infrared permafrost mapping of Ny Ålesund / Svalbard and sea ice measurements with a ground resolution of 3cm in the Fram Strait. Ideas for future sensors are indicated such as an UAV-based system with instant image transmission and a lightweight, high resolution sensor for stratospheric platforms.

 
Zooming in on crystal mush: recent advances in volcano tomography
Authors: Paulatto Michele , Morgan Joanna , Chrapkiewicz Kajetan , Hooft Emilie , Toomey Doug , Papazachos Costas , Nomikou Paraskevi , Heath Ben
Published: March 2021

The lack of direct seismological evidence for large molten magma chambers is considered to be one of the most important arguments in support of the mush paradigm. However, most published melt fraction estimates based on interpretation of seismological data are associated with large uncertainties because of two limitations: i) inherent limits to resolution of seismic tomography and, ii) trade-offs in the constitutive relationships that tie seismic properties to melt fraction. Low-velocity volumes associated with magma storage are particularly difficult to image with conventional travel-time tomography due to limited resolution and wavefront healing, resulting in blurred images and a high velocity bias. We tackle these limitation by applying full waveform inversion to active source seismic data collected over the Kolumbo submarine volcano (Greece). We recover a previously undetected Vp anomaly of –50% beneath the volcano and interpret this as a shallow magmatic intrusion. Extension of this approach to the wider Santorini volcanic system is ongoing. Concurrently, we are tackling the second limitation, which is the result of the dependence of elastic properties on the microgeometry of the melt. Seismological melt estimates rely on the assumption that the melt pore space can be represented by simple geometrical shapes, usually ellipsoids, with a given aspect ratio. Since the aspect ratio is poorly constrained, this results in a trade-off between melt fraction and melt geometry. We have adapted a method for the homogenisation of the elastic properties of multi-phase composites and applied it to calculating the elastic properties of partially molten rocks starting from the melt microstructure determined by X-ray CT scanning. The microgeometry of the mush can be inferred from the study of glomerocrysts: crystal mush inclusions with quenched interstitial melt that are carried to the surface by erupted lava. After the sample is digitized and segmented into its constitutive phases (crystals, melt, vesicles), the average elastic properties are determined by numerical homogenisation which consists of numerically simulating the deformation of the sample under load and predicting its elastic response. The results are compared to a semi analytical solution for ellipsoidal inclusions. We apply this approach to a plutonic nodule from St Kitts and show that the melt microstructure leads to an elastic response equivalent to that of ellipsoidal melt inclusions with an aspect ratio of 0.1 (oblate spheroids). This equivalent aspect ratio is used to refine melt estimates for Montserrat, Santorini and Kolumbo volcano.
Sensitivity of snow cover spatio-temporal dynamics to the spatial distribution of meteorological forcings in a mid altitude alpine catchment: model analysis
Authors: Gupta Aniket , Voisin Didier , Cohard Jean-Martial
Published: March 2021

Mountainous catchments play an important role in water regulation as they store water along winter time and release it when snow melts several months after precipitations. Mid-altitude catchments are more prone to respond to climate changes as snow cover dynamics is directly impacted by temperature changes. Along with large scale precipitation events snow cover dynamics is also driven by small scale terrain characteristics which impact deposition, wind transport, melting through distributed solar insolation along slopes. These highly characteristic patterns impact snow cover dynamics significantly and the hydrological response even in small catchments.

This study focus on a small mid altitude alpine catchment at Col du Lautaret (France) which is a 15.28 ha subalpine catchment with the elevation range between 2000-2200 meter, typically 5-6 months period of full snow coverage over a grass dominated vegetation. Over this catchment, we simulated the impact of small scale snow spatial variability on the water cycle with the surface-subsurface coupled hyper-resolution distributed hydrological model ParFLOW/CLM. It consisted in several meteorological forcing scenarios prescribed to the model including distributed (2D) or non-distributed (1D) precipitation, solar radiation and wind. The model is able to simulate the snow cover distribution through the CLM energy balance module according to a combination of these forcings. The water transfers are then calculated through the Richards and kinematic wave equations following the ParFLOW formulation.

2D forcings induce a more spatially heterogeneous snowpack, which becomes patchy at the melt season. This asynchronous melt results in a longer melt period and a smoother hydrological response. However, 1D forcings do not generate such patchiness. Amongst the mechanisms responsible for the 2D distribution of the forcings, precipitation redistribution is the most important. Solar insolation distribution ads to the differential melting and wind distribution is not very important as a primary agent on the surface energy budget, but is important as it impacts precipitation redistribution in the watershed, which we treated separately.
Forecasting rare stratospheric transitions using short simulations
Authors: Finkel Justin , Webber Robert J. , Gerber Edwin P. , Abbot Dorian S. , Weare Jonathan
Published: March 2021

Nonlinear atmospheric dynamics produce rare events that are hard to predict and attribute due to many interacting degrees of freedom. A sudden stratospheric warming is a spectacular example in which the winter polar vortex in the stratosphere rapidly breaks down, inducing a shift in midlatitude tropospheric weather patterns that persist for up to 2-3 months.  In principle, lengthy numerical simulations can be used to predict and understand these rare transitions.  For complex models, however, the cost of the direct numerical simulation approach is often prohibitive.  We describe an alternative approach which in principle only requires relatively short duration computer simulations of the system.  Applying this methodology to a classical idealized stratospheric model with stochastic forcing, we compute optimal forecasts of sudden warming events and quantify the limits of predictability.  Statistical analysis relates these optimal forecasts to a small number of easy-to-interpret physical variables.Remarkably, we are able to estimate these quantities using a data set of simulations much shorter than the return time of the warming event.
Estimating and modeling spatio-temporal complex-valued covariance functions
Authors: Maggio Sabrina , Posa Donato , De Iaco Sandra , Cappello Claudia
Published: March 2021

Oceanographic data belong to the wide class of vectorial data, for which the decomposition in modulus and direction is meaningful, and the vectorial components are characterized by homogeneous quantities, with the same unit of measurement. Another feature of oceanographic data is that they exhibit spatio-temporal dependence.
In Geostatistics, such data can be properly modelled by recalling the theory of complex-valued random fields. However, in the literature, only techniques for modeling and predicting the spatial evolution of these phenomena were proposed; while the temporal dependence was analyzed separately from the spatial one, or just time-varying complex covariance models were used. Thus, the novelty of this paper regards some advances of the complex formalism for analyzing complex data in space-time and new classes of spatio-temporal complex covariance models.
A case study on spatio-temporal complex estimating and modeling with oceanographic data is provided and a comparison between two classes of complex covariance models is also proposed.
Soil microbial responses to passive restoration strategies in drylands: a temporal comparison of soil biodiversity and ecosystem function
Authors: Stewart Jana , Machado de Lima Nathali , Kingsford Richard , Muñoz-Rojas Miriam
Published: March 2021

Arid and semi-arid (from hereafter dryland) ecosystems cover 70% of Australia, with climate change set to increase this area through desertification. Increased temperatures and reduced water availability are compounded through agricultural overgrazing. This degradation and habitat loss has led to biodiversity loss which disrupts the biogeochemical cycles that maintain these environments, creating a negative feedback loop, and making restoration efforts largely unsuccessful. With soil microbes being important drivers in dryland systems, understanding how different stressors impact the soil biome is needed to improve conservation and restoration efforts and promote resilience and resistance to climate change. Particularly lacking is understanding of these interactions over time.

Fowlers Gap Research Station is the only research station in the arid zone of Australia and was a working sheep station until 2019. Due to agricultural overgrazing the site is largely degraded however exclusion zones have been set up on the property ranging in time from 3 years to 40 years. These exclusion zones provide a powerful comparison for the impact of soil degradation on drylands. To investigate the impact of overgrazing on the soil biodiversity and ecosystem functions, we selected three of the exclusion zones paired with three degraded sites directly outside of the exclusion zone to assess their microbial composition and functional diversity, along with soil physicochemical properties. We aim to build 16S rRNA gene libraries and co-relate them with the soil chemical variables, to assess the impact of overgrazing on these microbial communities and the ecosystem functions they provide. This knowledge can be used to improve monitoring of conservation and restoration initiatives by providing environmental indicators for soil health over time.
Effects of temperature rise (+5°C) on millet growth and mycorrhization and soil microbial community of culture
Authors: Diatta Sally , Mboup-Founoune Hassna , Diakhaté Sidy , Diouf Diégane
Published: March 2021

Our planet is marked by significant climatic variations, particularly with the warming of temperatures and the variation in rainfall. In sub-Saharan Africa, the impacts of climate change are more pronounced because agriculture is highly dependent on climate, hence its vulnerability to climate variability (Vanluwe et al., 2011). In the context of changing environmental conditions, the use of innovative agricultural practices to contribute to plant adaptation is necessary to support food security challenges. Agroecological practices to improve crop yields and sustainable soil fertility management. Soil is the main reservoir of biodiversity as it hosts a very high diversity of interacting living species, which can be distinguished according to their size, macrofauna, mesofauna and microorganisms that constitute a particularly important component of soil (Brady and Weil, 2002), particularly for the provision of ecosystem services to humans. This work is therefore interested in studying the contribution of arbuscular mycorrhizal fungi (AMF) to the growth of millet (Pennisetum glaucum) under warmer temperature conditions and the behaviour of microbial community in soil of millet growing.

Millet is grown in a plant climate chamber and inoculated with a selected mycorrhizal strain.  These millet growing conditions were carried out in two different temperatures: 32°C (normal temperature) and 37°C (warmer temperature).

The results showed that in conditions of warmer temperature the inoculation induced a significant vegetative growth of millet even with a low intensity of mycorrhization and so it improves microbial nutrient mineralization mediate vegetation growth.

In soil of millet growing, a significant increase in microbial biomass with 42.7 in warmer temperature condition compared to control temperature 16.7. Results of DGGE shows also a soil abundance and SMB diversity of the total fungal community was noted under warmer temperature condition.

This study showed that climate variation may affect soil symbiosis but not the potential for promoting plant growth of fungi. The use of arbuscular mycorrhizal fungi on the one hand as a biofertilizer can be an alternative in the context of reducing chemical inputs in agriculture and developing ecologically intensive agriculture (EIA) and on the other hand an adaptive practice  to apprehend the predicted climate changes.
Magmatic evidence for Late Carboniferous-Early Permian slab breakoff and extension of the southern Mongolia collage system in Central Asia
Authors: Zhou Hai , Zhao Guochun , Zhang Donghai
Published: March 2021

Oceanic subduction and its last underthrusted part can both triggers arc-like magmatism. As the existence of multi-subduction zones in the Central Asian Orogenic Belt, controversy still surrounds on when and especially how the subduction of the (Paleo-Asian Ocean) PAO terminated. We present geochronological, geochemical, and Lu-Hf isotopic data for a suite of basalt-andesites, dacite-rhyolites and later trachyandesite-mugearitic dykes from the Khan-Bogd area in the Gobi Tianshan Zone (GTZ) of the southern Mongolia. U-Pb dating of zircons indicate the basalt-andesites and dacite-rhyolites were formed at ~334-338 Ma, and the dykes at ~300 Ma. These Early Carboniferous volcanic rocks display high U/Th, Ba/Th, low La/Sm and variable Zr/Nb ratios, implying the involvement of subduction fluids or sediment melt. They display arc geochemical features such as calc-alkaline and metaluminous nature and positive Ba and U and negative Nb, Ta and Ti anomalies. Moreover, their continental geochemical signals (e.g. positive Pb, K anomalies) and some old captured zircons implying a continental arc setting. Comparatively, the ~300 Ma dykes are characterized by high alkaline contents, which are common for coeval (~320-290 Ma) and widespread post-subductional granites there. Given a mainly crust-derived magma source for those granites, these dykes likely reflect a mantle disturbance due to: (1) their relative low SiO2 (51.71-55.85 wt. %) and high Mg# (40.3-67.3) values, and (2) positive zircon ƐHf(t) (most > 12). Considering a slab rollback model during the Carboniferous and Triassic, the mantle disturbance was possibly induced by the oceanic slab breakoff. Combined with previous work, this ~320-290 Ma slab breakoff-induced extension marks the closure of a wide secondary ocean (North Tianshan-Hegenshan ocean) north of the main ocean basin of the PAO. This research was financially supported by NSFC Projects (41730213, 42072264, 41902229, 41972237) and Hong Kong RGC GRF (17307918).
Late Paleozoic tectonism of the Bogda region in  Chinese North Tianshan: Insights from sedimentary provenance analysis
Authors: Wang Qian , Zhao Guochun , Han Yigui , Yao Jinlong
Published: March 2021

The Chinese North Tianshan (CNTS) extends E-W along the southern part of the Central Asian Orogenic Belt and has undergone complicated accretion-collision processes in the Paleozoic. This study attempts to clarify the late Paleozoic tectonism in the region by investigating the provenance of the Late Paleozoic sedimentary successions from the Bogda Mountain in the eastern CNTS by U-Pb dating and Lu-Hf isotopic analyses of detrital zircons. Detrital zircon U-Pb ages (N=519) from seven samples range from 261 ± 4 Ma to 2827 ± 32 Ma, with the most prominent age peak at 313 Ma. There are Precambrian detrital zircon ages (~7%) ranged from 694 to 1024 Ma. The youngest age components in each sample yielded weighted mean ages ranging from 272 ± 9 Ma to 288 ± 5 Ma, representing the maximum depositional ages. These and literature data indicate that some previously-assumed “Carboniferous” strata in the Bogda area were deposited in the Early Permian, including the Qijiaojing, Julideneng, Shaleisaierke, Yangbulake, Shamaershayi, Liushugou, Qijiagou, and Aoertu formations. The low maturity of the sandstones, zircon morphology and provenance analyses indicate a proximal sedimentation probably sourced from the East ­Junggar Arc and the Harlik-Dananhu Arc in the CNTS. The minor Precambrian detrital zircons are interpreted as recycled materials from the older strata in the Harlik-Dananhu Arc. Zircon ɛHf(t) values have increased since ~408 Ma, probably reflecting a tectonic transition from regional compression to extension. This event might correspond to the opening of the Bogda intra-arc/back arc rift basin, possibly resulting from a slab rollback during the northward subduction of the North Tianshan Ocean. A decrease of zircon ɛHf(t) values at ~300 Ma was likely caused by the cessation of oceanic subduction and subsequent collision, which implies that the North Tianshan Ocean closed at the end of the Late Carboniferous. This research was financially supported by the Youth Program of Shaanxi Natural Science Foundation (2020JQ-589), the NSFC Projects (41730213, 42072264, 41902229, 41972237) and Hong Kong RGC GRF (17307918).
Size-resolved effective density of submicron aerosol particles in the North China Plain
Authors: Zhou Yaqing , Ma Nan , Wang Zhibin , Tao Jiangchuan , Hong Juan , Peng Long , Xie Linhong , Zhu Shaowen , Chen Chunrong , Zhang Qiang , Su Hang , Cheng Yafang
Published: March 2021

Effective density is one of the most important physical properties of atmospheric aerosol particles, and is linked to particle formation and aging process. Combined characterization of aerosol density, chemical composition, emission and aging processes may provide crucial information for better understanding their interactions and effects on environment and climate. In autumn of 2019, the effective density of sub-micrometer aerosol particles was measured in-situ at a heavily polluted rural site in the North China Plain (NCP). A tandem technique coupling a Centrifugal Particle Mass Analyzer (CPMA) with a differential mobility analyzer (DMA) and a Condensation Particle Counter (CPC) were used to determine the effective density of ambient aerosol particles with diameters of 50, 100, 150, 220 and 300 nm. The probability distribution of effective density exhibits double peak modes in majority cases, with a higher density mode (main-density) and a lower density mode (sub-density). The existence of sub-density particles normally ascribed to freshly emitted or partial aged black carbon (BC) with non-spherical morphology. The number fraction of sub-density mode varies from 4% to 67%, with mean of 22-27% at five particle sizes. Due to the higher aging degree of larger particles, the main-density exhibits an evident ascending trend with particle size. However, the sub-density decreases as mobility size increases, from 0.89 g/cm3 at 50 nm to 0.62 g/cm3 at 300 nm, since larger fresh soot particles usually present a more agglomerated morphology than small particles. A comparison was carried out between the mean effective density at 300 nm and ACSM-derived density using different approximations of BC density. The best agreement is achieved when assuming a BC density of 0.6 g/cm3, indicating that BC typically exists as non-spherical particles with fractal-like or porous morphology in the NCP in cold season.
Inventorying Retrogressive Thaw Slumps along the Qinghai-Tibet Engineering Corridor using a deep-learning-aided semi-automatic method
Authors: Xia Zhuoxuan , Huang Lingcao , Liu Lin
Published: March 2021

Permafrost in the Tibetan plateau is undergoing warming and degradation due to thermal and anthropogenic disturbance. As visible indicators of permafrost degradation, retrogressive thaw slumps (RTSs) are slope failures resulting from thawing of ice-rich permafrost, which can retreat and expand in thawing seasons, and may destroy infrastructure, change ecosystems and release carbon preserved in permafrost. However, the distribution of RTSs over Tibet is seldom investigated and poorly understood.

In this study, we used optical images collected by the Planet CubeSat constellation in 2019 to identify RTSs over a vast area of ~45000 km2 along the Qinghai-Tibet Engineering Corridor, where the main highways and railways across the plateau are running through and a new highway is under planning. We planned to use the deep learning model DeepLabv3+, which can classify every pixel in the entire study area. However, with limited training data (300 RTSs) centered in a relatively small subregion (Beiluhe Region), it is infeasible to delineate all RTSs accurately in such a large and diverse area by using deep learning alone. Therefore, we proposed an iteratively semi-automatic method. In each iteration, we used DeepLabv3+ to automatically identify and delineate all possible RTSs, then manually checked them and selected newly-found RTSs based on their geomorphic features and temporal changes. To minimize the chance that DeepLabv3+ may miss some RTSs in each iteration, we added newly-found RTSs into the positive training dataset for the next iteration. We stopped iteratively mapping until no new RTSs could be identified.

Eventually, our method identified and delineated 877 RTSs which affect a total area of 17 km2. They tend to spread out across the region, while Beiluhe is characterized as a cluster. Among these, 57 RTSs are within 500 m from major roads and the railway and potentially threaten their safety. This study demonstrates the applicability of using our deep-learning-aided method to obtain a comprehensive inventory of RTSs in large areas such as the engineering corridor, give us an overall understanding of RTS distribution, and provide an important benchmark dataset and knowledge for further quantifying temporal changes of RTSs.
A portable dual-channel laser heterodyne radiometer for simultaneous remote measurements of CH4 and CO2 in the atmospheric column
Authors: Wang Jingjing , Tan Tu , Xue Zhengyue , Gao Xiaoming , Chen Weidong
Published: March 2021

Laser heterodyne spectroscopic measurement technique[1] has been proved to be a powerful and effective remote sensing tool for measurements of greenhouse gases in the atmospheric column[2-6]. In the present work, we report the development of a portable all-fiber coupled dual-channel laser heterodyne radiometer (LHR) and its field deployment. Two DFB lasers operating at 1650.9 nm and 1603.6 nm are used for the remote measurements of column CH4 and CO2, respectively. A fiber optic switch is used to modulate and split the collected sunlight into two channels for simultaneous measurements of both target greenhouse gases. Custom-made preamplifiers combined with digital lock-in amplifiers are used to extract the laser heterodyne signals. The spectral resolution of the instrument is about 0.00442 cm-1, and the signal-to-noise ratio of the measured spectrum of about 250 is achieved with 0.8 s average time per sampling datum. The developed LHR instrument was successfully deployed to a field atmospheric observation experiment (in Dachaidan district, Qinghai province, China).

The experimental detail including the LHR instrument integration, dual-channel measurement results of column CH4 and CO2 and preliminary data inversion results will be presented and discussed.

Acknowledgments. The project was supported by the national key R&D program of China (2017YFC0209705). The authors thank the financial supports from the CPER CLIMIBIO program, the Labex CaPPA project (ANR-10-LABX005).

References

[1] D. Weidmann, T. Tsai, N. A. Macleod, G. Wysocki, Opt. Lett. 36 (2011) 1951-1953.

[2] E. L. Wilson, A. J. DiGregorio, G. Villanueva, C. E. Grunberg, et al., Appl. Phys. B 125 (2019) 211-219.

[3] D. S. Bomse, J. E. Tso, M. M. Flors, J. H. Miller, Appl. Opt. 59 (2020) B10-B17.

[4] J. Wang, G. Wang, T. Tan, G. Zhu, C. Sun, Z. Cao, W. Chen, X. Gao, Opt. Express 27 (2019) 9610-9619

[5] A. Rodin, A. Klimchuk, A. Nadezhdinskiy, D. Churbanov, et al., Opt. Express 22 (2014) 13825-13834.

[6] E. L. Wilson, M. L. McLinden, J. H. Miller, H. R. Melroy, et al., Appl. Phys. B 114 (2014) 385-393.
Modeling root water uptake depth driven by climate and soil texture using a simple bucket model approach
Authors: Adamczewski Ruth , Westermann Sven , Hildebrandt Anke
Published: March 2021

Root water uptake (RWU) in grasslands is determined by species composition, climate and soil hydraulic properties. Generally, plant communities are adapted to their environment, showing different rooting patterns along climate gradients. Due to climate change, ecosystems are exposed to shifts in precipitation patterns and rising temperatures, causing the need to adapt rooting strategies. RWU is mainly driven by plant transpiration and soil hydraulic status in the rooting zone. Soil hydraulic properties depend strongly on soil texture, which has been observed to influence rooting depth, increasing the root length from fine to coarse soils. Secondly, precipitation patterns affect the typical soil moisture status, and subsequently the rooting depth. Global models suggest that in dry environments RWU should move deeper, to enhance the plant available soil water. However, few studies have at the same time considered the effect of climate and soil properties on RWU depth, although soil properties vary substantially and probably more than precipitation patterns due to climate change.

Biogeochemical models suffer from uncertainty in subsurface hydrological processes, RWU being an important part of it. Thus, ecohydrological models are needed for an integration in larger context biogeochemical models. The trend of ecological models is towards high parameterized models, implying high uncertainty and challenging calibration for those parameters. Especially in the subsurface, parameters are often unknown and are usually impossible to derive from direct measurements. In this project, a simple, parsimonious bucket model was implemented, solving the water balance equation for a multi-layer soil profile. The objective of this work is to predict maximum required RWU depth required to satisfy potential evapotranspiration across established experimental grassland sites with different climate and soil water retention properties. For this we use soil moisture measurements, textures and hydraulic properties determined in three grassland sites of the Nutrient-Network (NutNet) across a climate gradient. We test the sensitivity of the model towards climate and soil hydraulic parameters. First model results show a high sensitivity of RWU depth besides to dynamics to climate, also to soil water retention determined by texture and organic matter content in the soils.
Some aspects of Rossby waves and non-linear dynamics
Authors: Hoskins Brian
Published: March 2021

Rossby waves are able to communicate weather anomalies in one region to other regions. There anomalous weather events can follow if the wave is persistent and large amplitude. They can also be caused by breaking of the wave leading to blocking. The impact on the middle latitudes via stationary Rossby wave trains triggered by tropical convection anomalies has been of interest for many years. However, tropical convective events can also interact with higher latitude jet streams and the weather systems on them through a very different mechanism. In this talk, some examples will be given that indicate the flaring of tropical convection can lead to strong upper tropospheric outflows in which filaments of air with near equatorial values of PV interact with higher latitude jet streams and the weather systems on them.
The relationship between temperature and digital hate – strong increase of racist tweets outside of climate comfort zone in Europe
Authors: Stechemesser Annika , Wenz Leonie , Kotz Maximilian , Levermann Anders
Published: March 2021

Temperature has been identified as a potential cause for human conflict. Conflict poses a fundamental obstacle to Sustainable Development Goal 16 which acknowledges the importance of building peace, justice and strong institutions for people around the world. Today, conflict is no longer limited to the physical space. The increasing digitalization of all areas of everyday life reinforces the impact of cyber racism, cyber discrimination and online hate. It disproportionally affects groups with an already increased risk of marginalization such as women, lgbtq+ youth or people of color, causing affected persons to feel unsafe in digital spaces and limiting their access to online services. Twitter is one of the biggest social media platforms with more than 300 million active users around the world. We provide evidence that the amount of racist content posted to Twitter is non-linearly influenced by temperature. Exploiting the linguistic plurality of Europe, we investigate the relationship between daily maximum temperature and racist or xenophobic content online using a fixed-effects panel-regression approach for countries spanning multiple European climatic zones. Racist tweets are lowest between daily temperatures of 8°C to 17°C whereas ambient temperatures warmer or colder are associated with steep, non-linear increases. Within the next 30 years, temperatures are projected to shift with new heat extremes being reached. To quantify the potential impact on cyber hate, the number of days outside this range, weighted by the identified temperature-racist-tweet response curve is projected to increase across Europe. Results suggest, that future warming and more extreme temperatures could aggravate xenophobia and racism online, further hindering the achievement of SDG 16 and posing a challenge for future human well-being.  
Detection of living bacterial cells in clay - bentonite 
Authors: Hlavackova Veronika , Cerna Katerina , Kejzlarova Lenka , Bartak Deepa , Shestra Rojina , Sevcu Alena
Published: March 2021

Bentonite is a swelling clay, consisting mainly of montmorillonire,  being planned to be used as a backfill material in the nuclear waste repository. It contains indigenous microbial populations that can negatively influence the long-term safety of the geological repository due to their metabolic activity (canister corrosion, illitization of bentonite, gas production, degradation of cementitious materials). However, reliable detection of microorganisms in clayish material is generally very difficult. Although the compactness of bentonite will undoubtedly limit the microbial activity, in the extremely long-time frame of repository lifetime this condition can fail. It is thus crucial to understand the potential of the naturally present microbial community in bentonite to compromise the safety of repository, if not limited by the compactness. Higher metabolic activity can be mainly expected at the interfaces or in the places with a lower density of bentonite.

Here we present an optimized cell extraction method enabling direct estimation of bacterial density and viability in bentonite. Indigenous bacterial cells were extracted from bentonite suspensions by an improved step-wise protocol and their viability was detected using live/dead staining and epifluorescence microscopy. We used dispersant (2.5 mM natrium pyrophosphate-based solution or 1% methanol) to partially disintegrate the bentonite and detach the vital and dead microbial cells from its surface. The dispersed material was subsequently stepwise centrifuged over two high-density media (sucrose and Histodenz) to remove most of the heavy bentonite particles while keeping the light bentonite particles and cells in the final extract. We were able to detect and enumerate the cells concentrated at the surface of the light bentonite particles, which served as a sieve to retain all free cells during centrifugation.    

Different extraction procedures were tested and their efficiency was estimated by comparing live/dead ratios of resulting extracts and was also proved by implementing both NGS and quantitative PCR. The results show that most of the microbial genera present in the original suspension are also present in extracts but as proved by Deseq2 analysis some genera tend to settle down with heavier bentonite particles during the first centrifugation step.

To conclude, we present a protocol for extraction and detection of metabolically active cells in clayish material – bentonite. The quality of the extraction procedure was estimated both by a combination of fluorescent microscopy and genetic methods. The protocol was successfully tested on different bentonite types showing general applicability of this approach for clay materials.
Precipitation nowcasting based on multifractal advection and deformation 
Authors: Santos-Duarte-Ramos Victoria
Published: March 2021

The X-band radars deliver precipitation estimates with high accuracy and space resolution (up to 100 m in space and 1 min in time). With their increasing deployment around large cities, there is an appealing need for short-term nowcasting of rainfall at high resolutions for urban applications.

Nowcasting means forecasting with lead times of up to six hours. Classical precipitation nowcasting methods include methods of image processing to identify precipitation cells and extrapolate their motion. Due to the strong nonlinearity of the precipitation processes, such methods face a number of limitations, e.g., cell identification lacks physics and can be quite ad-hoc or even fail because of their fast deformation. On the contrary, this presentation aims to demonstrate how the fast multiscale deformation of the rainfall cells could be used to improve precipitation nowcasting, with the help of new radar data and products.

Spectral and multifractal analyses of radar data enable a comparison of the structure and the morphology of both the precipitation and vector fields through space time scales. This provides a unique framework to nowcast both fields over scales relevant to urban decision-making. Overall, this presentation contributes to the development of new, reliable, operational tools to use in their full extent the high-resolution X-band data.
AusGeochem and Big Data Analytics in Low-Temperature Thermochronology
Authors: Boone Samuel , Kohlmann Fabian , Theile Moritz , Noble Wayne , Kohn Barry , Glorie Stijn , Danišík Martin , Zhou Renjie
Published: March 2021

The AuScope Geochemistry Network (AGN) and partners Lithodat Pty Ltd are developing AusGeochem, a novel cloud-based platform for Australian-produced geochemistry data from around the globe. The open platform will allow laboratories to upload, archive, disseminate and publish their datasets, as well as perform statistical analyses and data synthesis within the context of large volumes of publicly funded geochemical data. As part of this endeavour, representatives from four Australian low-temperature thermochronology laboratories (University of Melbourne, University of Adelaide, Curtin University and University of Queensland) are advising the AGN and Lithodat on the development of low-temperature thermochronology (LTT)-specific data models for the relational AusGeochem database and its international counterpart, LithoSurfer. These schemas will facilitate the structured archiving of a wide variety of thermochronology data, enabling geoscientists to readily perform LTT Big Data analytics and gain new insights into the thermo-tectonic evolution of Earth’s crust.

Adopting established international data reporting best practices, the LTT expert advisory group has designed database schemas for the fission track and (U-Th-Sm)/He methods, as well as for thermal history modelling results and metadata. In addition to recording the parameters required for LTT analyses, the schemas include fields for reference material results and error reporting, allowing AusGeochem users to independently perform QA/QC on data archived in the database. Development of scripts for the automated upload of data directly from analytical instruments into AusGeochem using its open-source Application Programming Interface are currently under way.

The advent of a LTT relational database heralds the beginning of a new era of Big Data analytics in the field of low-temperature thermochronology. By methodically archiving detailed LTT (meta-)data in structured schemas, intractably large datasets comprising 1000s of analyses produced by numerous laboratories can be readily interrogated in new and powerful ways. These include rapid derivation of inter-data relationships, facilitating on-the-fly age computation, statistical analysis and data visualisation. With the detailed LTT data stored in relational schemas, measurements can then be re-calculated and re-modelled using user-defined constants and kinetic algorithms. This enables analyses determined using different parameters to be equated and compared across regional- to global scales.

The development of this novel tool heralds the beginning of a new era of structured Big Data in the field of low-temperature thermochronology, improving laboratories’ ability to manage and share their data in alignment with FAIR data principles while enabling analysts to readily interrogate intractably large datasets in new and powerful ways.
The effects of multiple factors on spring meltwater erosion on an alpine meadow slope
Authors: Shi Xiaonan , Zhang Fan , Wang Li
Published: March 2021

Serious soil erosion is observed during the spring because soil thawing coincides with the period of snowmelt and low meadow coverage at this time. Studies relating to soil erosion caused by spring meltwater are limited and controversial. In this study, a field experimental study was conducted in an alpine meadow slope in the Binggou watershed on the northern edge of the Tibetan Plateau to assess the impact of multiple factors on spring meltwater erosion. The multiple factors included three flow rates, four slope gradients, and three underlying surface conditions (meadow, disturbed meadow, and alluvial soil). An equal volume of concentrated meltwater flow was used in all experiments. The results showed that rapid melting at a high flow rate could accelerate soil erosion. The influence of the slope gradient on the amount of runoff was positively linear and the influence was relatively low. However, the slope gradient had a strong impact on soil erosion. The meadow could effectively reduce soil erosion, although when the meadow was disturbed, the total runoff increased by 60% and the sediment yield by a factor of 1.5. The total runoff from the alluvial soil doubled in comparison to the meadow, while the sediment yield increased nearly 7-fold. The findings of this study could be helpful to understand the characteristics and impact of multiple controlling factors of spring meltwater erosion. It also aims to provide a scientific basis for an improved management of alpine meadows as well as water and soil conservation activities in high-altitude cold regions.

 
Study on the precipitation gradient characteristics in the high mountains of southern Tibet
Authors: Zeng Chen , Zhang Fan
Published: March 2021

Precipitation usually is the main source of river discharge in the high mountain headwater areas and therefore as a key parameter in hydrological modelling. However, spatiotemporal distribution of precipitation in the remote high mountain headwater areas on the Tibetan Plateau (TP) has been poorly described due to the scarce meteorological stations located in high elevations. A series of rain gauges were set-up in three catchments of the southern TP to study their precipitation (liquid) gradient (PG) characteristics under different precipitation intensity grades (PIG) during the monsoon season (July to September) from 2013 to 2016. Results showed that the average PG varied during 0.71 to 0.82 mm·100 m-1 in the three study catchments for the total (non-intensity-graded) precipitation during the monsoon, and varied up to 2.4 times under different PIGs. Besides, PGs were all strongly correlated to precipitation amounts in the three study catchments, these patterns were relatively persistent among different years but varied among different catchments. Generally, the correlations between PG and precipitation amount showed a steep positive slope under fine precipitation grade but became flat or even negative with stronger PIG. We concluded that the precipitation in southern Tibet was influenced more by valley-scale convection than by large-scale vapor circulation during the monsoon season.
Framing the state-of-the-art on the use of software for sustainable groundwater resource management in the African continent
Authors: Rossetto Rudy , Veroli Sara , Chekirbane Anis , Crestaz Ezio , Carmona-Moreno Cesar
Published: March 2021

Groundwater is a resource of increasing prominence in Africa whose potential has still to be developed in full capacity. While it is clear that data gathering is of outmost importance to achieve a certain level of knowledge for many African aquifer systems, Information and Communication Technology may support and boost efficient data management. This way, more technically sound and even community-based decisions may be made. In this context, we attempted to frame the state-of-the-art on the use of digital tools for supporting sustainable groundwater management in the African continent. By means of a comprehensive literature review and performing investigations via a structured questionnaire on ongoing practices at institutional/private sector level, the results allow a clear view on the present level of knowledge and on the diffusion of such tools.

At present the use of digital tools/groundwater numerical models is deemed to be an occasional activity, mostly applied for large engineering projects or basic modelling studies, rarely used for planning and management of the resource. All in all, their use in the period 2000-2020 can be considered low, with a clear difference between North Africa and Sub-Saharan African countries. Digital tools are recognised as needed tools by African institutions at national/regional level. However, skills and capacities are largely missing: the need for capacity building is (extremely) high. Commercial software solutions still dominate the market, while open source ones appear in increasing trend of usage in the last years.

Finally, main barriers in the use of digital tools are: i) scarcity of data, ii) inadequate resources (lack of computing resources), and iii) missing capacities (lack of computing skills). In addition to these, the lack of adequate and well-functioning Internet connection is considered one of the main bottleneck in favouring the spread of new technologies. Capacity building and knowledge transfer has then to be on top of the agenda for a digital groundwater governance in Africa. In particular, training should be directed to favour the use (and re-reuse) of open-source applications and the often huge amount of information and contents available. A generation of experts with a sounding interdisciplinary background should be able, in five to ten years, to properly manage ICT applications.