bluuebunny/crossref_metadata_2025 huggingface dataset:
How fluid flow and heat transport models impact predictions of deep geothermal potentials: the "heat in place" method applied to Hesse (Germany)
Authors: Koltzer Nora , Bott Judith , Scheck-Wenderoth Magdalena , Bär Kristian
Published: March 2022

One key aspect in the energy transition is to use the deep geothermal energy stored in sedimentary basins as well as igneous and metamorphic basement rocks. To estimate the variability of deep geothermal potentials across different geological domains as encountered in the Federal State of Hesse (Germany), it is necessary to understand the driving processes of fluid flow and heat transport affecting subsurface temperature variations. In this study, we quantify the stored energy in geothermal reservoirs with the method of “heat in place” (sensu Muffler & Cataldi, 1978, as one proxy for geothermal potential) for different geological units as integrated in a series of coupled 3D thermo-hydraulic numerical models of Hesse. This way we can show how conductive, advective and convective heat transport mechanisms influence the thermal field and thereby the predicted “heat in place”.

In this work, the “heat in place” is calculated for each grid point in the model for a volume of one cubic meter times the reservoir thickness. The temperature is extracted by interpolation along the middle surface of each reservoir unit and thus considered as an average representative value of the integrated energetic input for each layer.

The heterogeneous geology of Hesse ranges from outcropping Paleozoic basement rocks to up to 3.8 km thick Cenozoic sedimentary deposits in the Upper Rhine Graben. This geological complexity is expressed by areas of different hydraulic and thermal configurations, strongly influencing the geothermal potentials.

The “heat in place” was quantified for five sedimentary layers: Cenozoic, Muschelkalk, Buntsandstein, Zechstein und Rotliegend as well as for the underlying variscan basement for the entire volume down to a maximum model depth of 6 km. In the Cenozoic, Buntsandstein and Rotliegend reservoir units, “heat in place” is predicted to be highest in the Upper Rhine Graben, where the modelled temperatures are higher than 90 °C in the reservoirs.

In general, we can assess geothermal potentials across the study area more comprehensively with the prediction of “heat in place” that is based on the thermal field derived from thermohydraulic simulations. For example, the conductive thermal field points to the Upper Rhine Graben as the most proliferous region due to highest predicted temperatures. With the convective simulations the area with high temperatures is reduced from the entire Graben to local zones of upwelling hot fluids. At the end, with the prediction of “heat in place”, we integrate even more parameters like the reservoir thickness and therefore suitable regions for geothermal utilization are even more restricted.

 
The Potential of Moonlight Remote Sensing: A Systematic Assessment with Multi-Source and Multi-Moon phase Nightlight Data
Authors: Liu Di , Zhang Qingling
Published: March 2022

Increased observation frequencies are current trends in optical remote sensing. However, there are still challenges at the night side when sunlight is not available. Due to their powerful capabilities in low-light sensing, nightlight satellite sensors have been deployed to capture nightscapes of the Earth from space, observing anthropomorphic and natural activities at night. At present, most nightlight remote sensing applications have mostly focused on artificial lights, particularly within cities or self-luminous entities such as fisheries, oil, shale gas, offshore rigs, and other self-luminous bodies. Little attention has been paid to examining the potential of nightlight remote sensing for mapping land surfaces in low-light suburban areas using satellite remote sensing technology. Observations taken under moonlight are often discarded or corrected to reduce the lunar effects. Some researchers have discussed the possibility of moonlight as a useful illuminating source at night for the detection of nocturnal features on Earth, but no quantitative analysis has been reported so far. This study aims to systematically evaluate the potential of moonlight remote sensing with the whole month of mono-spectral Visible Infrared Imaging Radiometer Suite/Day-Night-Band (VIIRS/DNB) and multi-spectral Unmanned Aerial Vehicle (UAV) nighttime images. The present study aims to:1) to study the potential of moonlight remote sensing for mapping land surface in low-light suburban areas; 2) to investigate the Earth observation capability of moonlight data under different lunar phases;3) to make two daily uniform nightlight datasets(moonlight included and removed) for various night scenes researches, like weather diurnal forecast, circadian rhythms in plants and so on; 4) to discuss the requirements for the next-generation nightlight remote sensing satellite sensors.
The hourly volcanic SO2 column density and a variety of novel volcanic SO2 products from Geostationary Environment Monitoring Spectrometer (GEMS) measurements over Asia
Authors: Park Jeonghyeon , Lee Hanlim , Yang Jiwon , Hong Hyunkee , Choi Woeni , Park Junsung , Kim Jhoon , Li Can , Roozedael Michel Van , Theys Nicolas , Ko Daiho , Lee Seunghoon
Published: March 2022

The Geostationary Environment Monitoring Spectrometer (GEMS) onboard the Geostationary Korea Multi-Purpose Satellite-2B (GEO-KOMPSAT-2B) satellite was launched in February 2020 and observes the hourly volcanic SO2 in geostationary orbit. We For the first time show the hourly changes in volcanic SO2 distributions emitted and transported from several volcanoes over Asia. The various physical characteristics of volcanic plumes have been investigated based on hourly volcanic SO2 measurements. We estimated transport direction, path and speed, and altitude of volcanic SO2 plume emitted from Nishinoshima in Japan, Etna in Italy, Taal volcano in the Philippines and Dukono located in Halmahera, Indonesia. Before the eruption, Taal volcanic SO2 plumes, which were found to present within PBL, were transported mostly less than 100 km in various azimuth directions. Gradual increase in SO2 column densities was observed for about two months before a volcanic eruption from Taal. It implies that it might be possible to warn a volcanic eruption in advance which is subject to further investigation. GEMS can be further utilized for an improvement in prediction accuracy of SO2 plume transport using chemical transport model due to the availability of hourly volcanic SO2 height information.
Mapping subsurface structural lineament and geothermal potential areas in Southern Thailand using GOCE gravity data
Authors: Phiranram Theethach , Chenrai Piyaphong
Published: March 2022

The Gravity field and steady-state Ocean Circulation Explorer (GOCE) is the European Space Agency's (ESA) satellite gravity mission and is a revolutionary tool to reveal geologic information from the Earth. Geothermal energy is heat energy within the earth’s interior that can developed for a low carbon energy in the future. We use the GOCE satellite integrated with other data to extract geophysical information that are related to geothermal such as boundaries of the subsurface structures and plutonic rocks. The study area is in southern Thailand where a large plutonic rock associated major faults in the area playing an important role in geothermal system.

In this study total horizontal derivative, tilt derivative, and improved logistic were applied to emphasize the subsurface structural lineament and lithology. The result shows that the geological characteristics in southern Thailand are well correlated with gravity model from GOCE’s data.
Evaluating biodiversity Offset effectiveness in landscape scale
Authors: Lee Seungyeon , Shin Yujin , Jeong Dayong , Jeon Seongwoo
Published: March 2022

Jeju island is located at the southern part of Korea peninsula which has unique natural resources due to volcanic eruption. This area has high demand of urbanization as well as high pressure of development since it is one of the best touristic places in Korea.(Ryu Hyeong Won & DongHo Jang, 2018) To mitigate the struggle between nature protection and development, environmental offset has been suggested (Martin et al., 2016; Quétier & Lavorel, 2011). But, because the effect of the offset turns out in the future, the appropriateness of offset is hard to calculate. Some research has been tried to predict future consequences of offset but either there are in virtual area or in defined area(Bull et al., 2014; Gordon et al., 2011). The object of this research is to quantify the effects of biodiversity offset in landscape level and find out the best way to keep no net loss in overall landscape. The study area is probable offset area of offsetability map (probable offset area map) derived from proceeding research. The effectiveness will be compared in four following scenarios. 1) Business as usual. 2) applying offset randomly 3) applying offset considering landscape pattern 4) applying offset considering landscape pattern and size. Each scenario will presume the future landscape change and the total biodiversity change. As a result, the scenario with applying offset will increase its biodiversity value than business as usual. Furthermore, the offset applying pattern and size will affect the increasing rates of biodiversity values. This research is pointing out the importance of considering landscape pattern and size while applying biodiversity offset. Also, the result will support the political decision for offsetting development impact to improve overall biodiversity. This work was conducted with the support of the Korea Environment Industry & Technology Institute (KEITI) through its Urban Ecological Health Promotion Technology Development Project, and funded by the Korea Ministry of Environment (MOE) (2020002770003).
Probabilistic modelling and simulation of big spatio-temporal climate data for quantifying future changes of compound events
Authors: Economou Theodoros , Garry Freya
Published: March 2022

The analysis of climate change impacts involves the utilisation of climate model output. Quite often, quantities of interest are compound events rather than “raw variables” such as temperature. Questions such as "what is the probability that temperature will exceed a high threshold for five consecutive days and how will this change in the future?" are quite common. Statistical (probabilistic) modelling of climate model output can be used to answer such questions by stochastically simulating the raw variables and then quantifying the compound events as a “by-product”. This is particularly useful since any compound event can be investigated using the same approach – since the raw variables are the ones being modelled.

Such approaches however do not always scale well with big data sets and are often too complicated to even interpret appropriately. Here we present a way of analysing such data, using the (well-established) idea of a ‘moving window’ in conjunction with penalised smoothing splines and Generalised Additive Models (GAMs). The probabilistic nature of the resulting predictions provides a way of extrapolating beyond the range of the original data to robustly quantify the likelihood of rare events and their future changes. The approach is implemented in the Bayesian framework which results in full quantification of the associated uncertainty in using this method, e.g. increased uncertainty for extreme events way outside the range of the original data.

The method is both scalable and paralleliseable and we present it in quantifying changes in regional climate model output. Due to the simplicity of the components that make up the approach, it can be argued that it is highly interpretable as well as robust to the choice of variables – we demonstrate this using temperature as well as humidity and precipitation, variables which are known to have very different statistical behaviour. We also demonstrate how the approach can be extended to capture the behaviour of more that one variable and use it to quantify the changes in compound hazard events such as the frequency of “warm-dry” days.
Rainfall partitioning respond for a wet and dry year conditions
Authors: Zabret Katarina , Šraj Mojca
Published: March 2022

The climate change strongly influences the hydrological cycle mainly due to redistribution of precipitation and changes in its seasonal patterns, resulting in longer dry periods and more intense heavy rainfall events. As precipitation is the main input for rainfall interception, throughfall and stemflow, we can expect the climate change to influence also these processes. In our study plot in Ljubljana, Slovenia, covering a small urban park with two separate groups of trees (Pinus nigra Arnold and Betula pendula Roth.), we have been performing throughfall, stemflow and rainfall measurements since January 2014. In that period, we have captured various rainfall events and the measurements are available for different periods. Among them we have also covered an especially wet (2014) and a dry (2015) year. According to the long term yearly rainfall amount, equal to 1355 mm, the total rainfall amount delivered during the year 2014 was much higher (1841 mm) and in the year 2015 considerably lower (1106 mm), which characterize those years as a wet and a dry one. For each year we have analysed the influence of meteorological conditions (e.g. rainfall amount, duration, intensity, air temperature, vapour pressure deficit, size and velocity of raindrops) on rainfall interception, throughfall and stemflow under each tree species using the boosted regression trees and random forest approach. Similar influences of the variables were recognized by both models. Comparison of the obtained results with previous analysis (e.g. Zabret et al., 2018, doi: 10.1016/j.jhydrol.2018.01.025; Zabret and Šraj, 2021, doi: 10.3389/ffgc.2021.663100) showed that the indicated influential variables for wet and dry year are to some extent similar to the variables, indicated as influential in leafless and leafed period. For example, the rainfall duration was recognized as one of the most influencing variables on rainfall interception during the wet year 2014, which was previously observed also for the leafless period. Additionally, rainfall intensity had significant influence on rainfall partitioning by birch tree during the dryer year 2015 as well as in the leafed period.
IceLines – A new service to monitor Antarctic ice shelf front dynamics
Authors: Baumhoer Celia A. , Dietz Andreas J. , Heidler Konrad , Kuenzer Claudia
Published: March 2022

Antarctica`s coastline is constantly changing by moving ice shelf margins and glacier tongues. This can influence the discharge of the Antarctic Ice Sheet if ice shelf areas with buttressing forces are involved. By now, glacier and ice shelf front changes are not tracked continuously due to time-consuming manual work. Hence, dynamics of the calving front position are often simplified by using the steady-state-calving assumption for modelling. To provide modelers with frequent and continuous time series of calving front change, we introduce the ice shelf front monitoring service “IceLines”. IceLines monitors major Antarctic ice shelf fronts based on Sentinel-1 radar imagery. The data set is automatically updated on a monthly basis and can be accessed via the EOC GeoService (geoservice.dlr.de) hosted by DLR. IceLines automatically downloads and pre-processes Sentinel-1 data for 36 selected shelves and glaciers, extracts the calving front based on a deep neural network and optimizes the result by post-processing. The processing chain of IceLines presents unprecedented dense time series of calving front change during the era of Sentinel-1 (2014-today). Whereas many previous challenges for automatic calving front detection were tackled (e.g. various glacier morphologies, backscatter changes, different polarizations), some limitations exist for ice shelves with excessive surface melt during summer or dry snow facies close to the front. We will present the current implementation, the derived calving front time series and validation results of IceLines. Discussions with the modelling community are welcome to further improve the IceLines data set for ice sheet and ice shelf modelling applications.
Study on the variation and diagnostic methods of eco-hydrological regime in Hanjiang River Basin
Authors: Cai Siyu , Li Zhe
Published: March 2022

This paper used a long series of daily flow data of Ankang section from 1960 to 2020 to diagnose eco-hydrological variations in the upper reaches of the Hanjiang River. Aiming at the problems of the single hydrological variable used in watershed hydrological variation diagnosis, a method for extracting the most Ecologically Relevant Hydrologic Indicators (ERHIs) based on sensitive indicators of similar years and diagnosing the variation period was proposed. In this method, 32 hydrological indexes in the IHA index system were used to diagnose hydrological variation instead of the traditional single index, and the IHA index were refined into wet season index and dry season index based on different hydrological characteristics. Ten years were randomly selected from the long series flow data as the sample years and ten similar years corresponding to each sample year were selected for the determination of ERHIs. The indexes with strong variation were selected from ERHIs to diagnose hydrological variation. Through comprehensive variation diagnosis calculation, the indexes with strong variation were the annual average duration index of low flow and the annual minimum 1-day flow index, with the period of variation from 1973 to 1977, and from 1973 to 1986, respectively. Combined with the climate change and human activities in the past 60 years, it is found that the time period of climate change and water conservancy project construction is consistent with the time period diagnosed in this paper. Therefore, the variation period from 1973 to 1986 is reasonable. Through this study, it can be concluded that the method has strong practicability in the diagnosis of hydrological variation, and the conclusion is consistent with the practice, which can fully reflect the characteristics of hydrological changes in the Hanjiang River Basin.
Trends in Africa’s Terrestrial Water Storage 
Authors: Boergens Eva , Güntner Andreas
Published: March 2022

The German-American satellite missions GRACE (Gravity Recovery and Climate Experiment) and its successor GRACE-Follow-On (GRACE-FO) observed the unique data set of total water storage (TWS) variations over the continents since 2002. With this nearly 20 years of data, we can investigate trends in water storage beyond the strong declining trends of the ice sheets and glaciers. Unlike all other continents, Africa exhibits an overall positive trend in TWS. This contribution will take a detailed look into Africa's water storage changes and trends. Further, we attempt to explain these trends by comparison to other hydrological observations such as precipitation.

The long-term TWS increase in Africa is most pronounced in the East-African rift centred around Lake Victoria and the Niger River Basin. Other regions such as Madagaskar exhibit a (statistically significant) negative TWS trend. Furthermore, the trends are not monotonous over time. For example, the increasing trend in East Africa only started around the year 2006 and accelerated after 2012. On the other hand, South Africa wetted until 2012 and dried again since then.

This study divides the African continent into climatically similar regions and investigates the regional mean TWS signals. They are more complex than a linear trend and sinusoidal annual and semiannual seasonality; thus, we employ the STL method (Seasonal Trend decomposition based on Loess). In this way, turning points are identified in the so-called trend component to mark significant trend changes.

The observed TWS changes in Africa are caused mainly by changing precipitation patterns, as observed, for example, with the GPCP (Global Precipitation Climatology Project) data set. In some regions, such as South Africa, the correlation between precipitation and TWS change is evident, whereas other areas show a more complex relationship between these two variables.

 
Recurrent Rossby wave packets in the Northern Hemisphere
Authors: Ali Syed Mubashshir , Meyer Lukas , Röthlisberger Matthias , Methven John , Zscheischler Jakob , Martius Olivia
Published: March 2022

Recurrence of Rossby wave packets in a short time, termed as RRWPs, can lead to persistent and extreme weather events. Here, we study top RRWP events in the two basins: the North Atlantic and the East Pacific basins during 1979–2018 using ERA-5 reanalysis data. With the help of composite maps, we answer questions such as what are the characteristics of these events? Do they have a preferred phase? Is a particular flow configuration conducive to such events? What is the role of atmospheric blocks? And, whether these events are initiated by a common pathway such as tropical forcings or have several different pathways? We find that these events have a preferred phase configuration which varies with season. Both North Atlantic and East Pacific events are dominated by specific wavenumbers. In winter, dominant wavenumbers are 3, 4, and 5. In contrast, wavenumbers 5, 6, and 7 dominate in JJA. Furthermore, we address the role of low frequency zonal flow, blocks, and tropical convection during RRWP events using a causal network framework.
Mapping the Biodiversity Conservation Value for Potential Offset Area
Authors: Shin Yu Jin , Lee Seungyeon , Jeong Dayong , Jeon Seongwoo
Published: March 2022

Jeju Island, the research area, has been registered as a UNESCO World Natural Heritage Site and has high biodiversity and ecological value, such as designation as a global geopark and biosphere reserve. It also has a beautiful landscape, so it is not only necessary for conservation but also highly demanded as a landscape resource (Kim et al., 2015; Ko, 2011). Accordingly, it is necessary to prioritize the conservation area that can reconcile the conflict between indiscriminate development and nature protection, as well as to establish potential offset sites for ‘No Net Loss’ in order to respond to development impacts. Selecting conservation areas based on biodiversity value can be an effective offset decision-making tool on where and how to prioritize conservation policies (Li et al., 2021; SANBI & UNEP-WCMC, 2016). There have been many studies on biodiversity conservation between excellent ecological value and development pressure in Jeju Island, but there are almost no studies on the implementation conditions of the offset or offset sites. We here aim to map a conservation area map in consideration of the environmental characteristics of Jeju Island and to select a potential offset area that can practically work offset. We will use ‘Zonation’ program, which is a systematic conservation planning-based model. Zonation is a useful land planning tool that can minimize development impact and realize biodiversity offset (Wintle, 2008; Lethomaki & Moilanen, 2013). The biodiversity attributes inputs required for running Zonation are potential habitat data using MaxEnt and environmental variable data. As a result, we will identify the spatial range and location of the potential biodiversity offset area through Zonation Priority Rank Map output. In addition, we can also analyze their spatial and environmental characteristics, and group out the shape of potential offset site composition (size or pattern). This study can be utilized as a basis for feasible offset policy by proposing potential offset areas through selecting conservation areas in Jeju Island. This work was conducted with the support of the Korea Environment Industry & Technology Institute (KEITI) through its Urban Ecological Health Promotion Technology Development Project, and funded by the Korea Ministry of Environment (MOE) (2020002770003).
Weather history encoding for machine learning-based snow avalanche detection
Authors: Gölles Thomas , Kapper Kathrin Lisa , Muckenhuber Stefan , Trügler Andreas
Published: March 2022

Since its start in 2014, the Copernicus Sentinel-1 programme has provided free of charge, weather independent, and high-resolution satellite Earth observations and has set major scientific advances in the detection of snow avalanches from satellite imagery in motion. Recently, operational avalanche detection from Sentinel-1 synthetic Aperture radar (SAR) images were successfully introduced for some test regions in Norway. However, current state of the art avalanche detection algorithms based on machine learning do not include weather history. We propose a novel way to encode weather data and include it into an automatic avalanche detection pipeline for the Austrian Alps. The approach consists of four steps. At first the raw data in netCDF format is downloaded, which consists of several meteorological parameters over several time steps. In the second step the weather data is downscaled onto the pixel locations of the SAR image. Then the data is aggregated over time, which produces a two-dimensional grid of one value per SAR pixel at the time when the SAR data was recorded. This aggregation function can range from simple averages to full snowpack models. In the final step, the grid is then converted to an image with greyscale values corresponding to the aggregated values. The resulting image is then ready to be fed into the machine learning pipeline. We will include this encoded weather history data to increase the avalanche detection performance, and investigate contributing factors with model interpretability tools and explainable artificial intelligence.
Subgrid modelling of pitch-angle diffusion for ion-scale waves in a global hybrid-Vlasov simulation
Authors: Dubart Maxime , Battarbee Markus , Ganse Urs , Spanier Felix , Suni Jonas , Johlander Andreas , Alho Markku , Bussov Maarja , Cozzani Giulia , George Harriet , Grandin Maxime , Manglayev Talgat , Papadakis Kostis , Pfau-Kempf Yann , Tarvus Vertti , Turc Lucile , Zaitsev Ivan , Zhou Hongyang , Palmroth Minna
Published: March 2022

Numerical simulations play a central role in modern sciences. The trade-off between the accuracy of the physical processes described and the cost of computational resources is often the main limiting factor in these simulations. In global hybrid-Vlasov simulations, such as Vlasiator, lowering the spatial resolution in order to save on resources can lead to key processes being unresolved. A previous study has shown how insufficient resolution of the proton cyclotron instabilities leads to a misrepresentation of ion dynamics. This leads to larger temperature anisotropy and loss-cone shaped velocity distribution functions. In this study, we present a numerical model to introduce pitch-angle diffusion in velocity space, at a spatial resolution where this process was previously not correctly resolved. We test two different methods to enable pitch-angle diffusion in the 3D cartesian velocity space of Vlasiator. We show that we are successfully able to isotropise loss-cone shaped velocity distribution functions, and that this method could be applied to large simulations in order to save computational resources and still correctly model the Earth's magnetosheath.
A synthetic soil approach to link microbial community composition to soil functions
Authors: Horak Julia , Schmidt Hannes , Hadziabdic Leila , Kits Kerim Dimitri , Richter Andreas
Published: March 2022

Linking soil functions to microbial community structure is arguably one of the greatest challenges in soil ecology, presumably due to the structural complexity and heterogeneity of soil across scales and time, as well as the large number of microbial taxa present. To overcome these impediments, we here introduce a model soil ecosystem - the “Synthetic Soil” - which allows soil structure and microbial community composition to be varied separately, to disentangle the complex relationship. The Synthetic Soil consists of a mixture of sterilized primary and secondary soil minerals and organic matter of plant and microbial origin, which together constitute the artificial soil matrix. This abiotic soil matrix is then inoculated with an in-silico designed, minimal microbial community, composed of 12 selected soil bacteria and fungi.

We demonstrate the applicability of the approach, by incubating the Synthetic Soil in a sterile environment for five weeks. During this period, an actively growing soil community established, indicated by stable respiration rates, increasing DNA- and ammonium concentrations, depletion of dissolved organic carbon, and by changes in relative abundances of the community members. Additionally, the minimal community was actively decomposing soil organic matter by the production of extracellular enzymes. In conclusion, the Synthetic Soil approach developed in this study, allows the construction of powerful and modifiable model ecosystems, which will make it possible to link soil functions to microbial community structure and thus to address fundamental questions of soil ecology.  
Pressure–temperature–time assessment for the intrusion of the spodumene-bearing dyke from Alijó (northern Portugal)
Authors: Santos-Loyola Nora , Roda-Robles Encarnación , Garate-Olave Idoia , Errandonea-Martin Jon , Lima Alexandre
Published: March 2022

The Barroso–Alvão Pegmatite Field (Galicia-Trás-os-Montes Zone of the Iberian Massif) has been a target of abundant geological and mineral resource exploration studies in the last decades. Since lithium demand is increasing significantly at global scale as critical raw material for green technologies, the region has acquired a special relevance in terms of Li exploration. Within the distinguished aplite-pegmatite types in the area, the dyke of Alijó (currently in exploitation) corresponds to the spodumene-bearing type. The estimation of the P-T-t conditions for its intrusion provides useful information to constrain petrogenetic processes related to the origin of the cited pegmatite field.

The presence of albite and K-feldspar coexisting in the studied dyke point to a high H2O activity in the pegmatitic melt, which would decrease the temperature (T) of the solidus. Additionally, the lattice twin observed in microcline indicates that the crystallization of orthoclase took place followed by a rapid decrease of T, leading to the conversion of orthoclase to microcline. Thus, the presence of the lattice twin shows that the crystallization T must have been above 450–500°C (Ribbe, 1983). Considering the abovementioned minimum crystallization temperatures, the paragenesis of both primary and secondary spodumene (the later as a result of primary petalite replacement) restricts the primary pressure conditions to 2–3 kbar (e.g. London, 1984). Besides this paragenesis, the occurrence of eucryptite supports a sufficiently rapid decrease of T (and P) to allow the coexistence of these phases in the studied aplite-pegmatite. In agreement with the mentioned, the frequently observed ‘comb-like’ Unidirectional Solidification Textures (UST) in the margins of the dyke imply a strong and rapid undercooling of the system, probably caused by the exsolution of a H2O-rich fluid phase from the pegmatitic melt, once intruded into the open fracture where it occurs, combined with the high contrast of T between the pegmatitic melt and the relatively cooled host metasedimentary rocks.

London, D., 1984. Experimental phase equilibria in the system LiAlSiO4–SiO2–H2O: a petrogenetic grid for lithium-rich pegmatites. American Mineralogist, 69: 995-1004

Ribbe, P. H., 1983. Feldspar mineralogy 2nd edition. De Gruyter, Berlin, 362pp

Financial support: European Commission’s Horizon 2020 Innovation Programme [grant agreement No 869274, project GREENPEG: New Exploration Tools for European Pegmatite Green-Tech Resources]

 
The effect of inheritance, rheology, and stress orientation on the 4-D evolution of rift systems
Authors: Gouiza Mohamed , Vasileiou Athanasia , Naliboff John
Published: March 2022

Continental rifts often show a complex spatial and temporal evolution, controlled by the intricate interaction of several ingredients. Inheritance, plate rheology, and stress orientation are amongst the main factors that shape rifts and dictate their fate. In this contribution, we use observations from two rift systems – i.e., the Labrador Sea and the Atlas System – to constrain 3D geodynamic models and assess the role of inherited structures, rheological heterogeneities, stress field (re-) orientation and obliquity on rift evolution.

The Labrador Sea formed as a branch of the North Atlantic Ocean, which propagated across major Precambrian suture zones. The subsequent rifted margins show striking lateral changes in the structural architecture, the crustal geometry, and the magmatic budget during breakup. Our geophysical data analysis and 3D geodynamic models suggest that pre-rift rheological changes in the lithosphere (i.e., composition, thickness, and thermal structure) dominated the rifting process and the ensuing continental breakup.   

The Atlas fold and thrust belt is a failed rift system that evolved in Mesozoic times and was inverted in the Cenozoic. The rifting phase was driven by two concurrent extensional stress fields linked to the coeval opening of two highly oblique oceans: the Central Atlantic and the Tethys. Here, our 3D geodynamic models constrained by field observations highlights the importance of the pre-rift structural template in dictating the strain distribution/localization, the lithospheric extension mode (i.e., orthogonal rifting vs. transtension), and the location of magmatism.
MeteoInfo: An open-source GIS, scientific computation and visualization platform
Authors: Wang Yaqiang
Published: March 2022

Earth science data usually have distinct three-dimensional spatial characteristics, in which the state of the atmosphere changes rapidly, the time dimension is also very important, and the variables that describe various physical and chemical states together constitute the earth science cube. GIS, scientific computation and visualization tools are important to find and extract patterns and scientific views behind the data. MeteoInfo open-source software was developed as an integrated framework both for GIS application and scientific computation environment with two applications for end users: MeteoInfoMap and MeteoInfoLab. MeteoInfoMap makes it quick and easy to explore many kinds of geoscience data in the form of GIS layers, and includes spatial data editing, projection and analysis functions. MeteoInfoLab includes multidimensional array calculations, scientific calculations such as linear algebra, and 2D/3D plotting functions, which are suitable for completing the tasks of geoscience data analysis and visualization. The software was developed using Java and Jython, which makes it has good cross-platform capabilities and can run in operating systems such as Windows, Linux/Unix, and Mac OS with Java supporting.

The functions can be conveniently extended through development of plugin for MeteoInfoMap and toolbox for MeteoInfoLab. For example, TrajStat plugin was developed for air trajectory analysis and air pollution source identification, which has been widely used in air pollution transport pathway and spatial sources studies. Several MeteoInfoLab toolbox were also developed for model evaluation (IMEP), air pollution emission data processing (EMIPS) and machine learning (MIML). MeteoInfoLab has similar functions with Python scientific packages such as numpy, pandas and matplotlib, also Jython is just Python in Java. So, the users can learn MeteoInfoLab easily when they have Python experience, vice versa. 3D visualization functions are more powerful in MeteoInfoLab due to the usage of opengl acceleration. Also, 3D earth coordinate is supported to plot geoscience data on virtual earth.

References:

Wang, Y.Q., 2014. MeteoInfo: GIS software for meteorological data visualization and analysis. Meteorological Applications, 21: 360-368.

Wang, Y.Q., 2019. An Open Source Software Suite for Multi-Dimensional Meteorological Data Computation and Visualisation. Journal of Open Research Software, 7(1), p.21. DOI: http://doi.org/10.5334/jors.267

Wang, Y.Q., Zhang, X.Y. and Draxler, R., 2009. TrajStat: GIS-based software that uses various trajectory statistical analysis methods to identify potential sources from long-term air pollution measurement data. Environmental Modelling & Software, 24: 938-939
Soil micro-food web adaptations to stoichiometric imbalance regulate soil multifunctionality
Authors: Li Bing , Li Yingbin , Han Xu , Li Yuhui , Li Qi
Published: March 2022

Ecological stoichiometry theory plays a crucial role in linking ecosystem process. The interactions between organisms and/or between organisms and abiotic environment are strongly affected by the biological demand for elements and their supply by environment. Therefore, the complex feedback between the elemental stoichiometry of organism and their resources maintains the functioning of ecosystem. However, whether and how the multiple responses of soil micro-food webs to stoichiometric imbalance affect the soil multifunctionality have never been assessed so far. In this study, we tested the soil multifunctionality along the forest-steppe ecotone and assessed several potential adaptation mechanisms of soil micro-food web responding to elemental limitations including soil microbial stoichiometry, extracellular enzyme activities and the composition of soil communities as well as ecological network. The soil multifunctionality gradually decreased from forest towards steppe. The microorganisms invested more C-acquiring enzymes over nutrient-acquiring enzymes with decreasing soil C:N:P ratios, while the increasing C limitation in steppe soil enhanced microbial threshold element ratio and carbon-use efficiency. The changes in extracellular enzyme activity and community structure of soil micro-food web had a stronger impact on soil multifunctionality. The multiple adaptive pathways of soil micro-food web to the stoichiometric imbalance of resources, jointly affected the multifunctionality of soil. Our study provides deeper insights into how stoichiometric constraints may induce shifts in soil micro-food web and then influence the ecosystem functioning. Our findings have important implications for integrating shifts in individual physiological metabolism as well as changes in community composition of soil biota and for better understanding the relations of soil biodiversity and soil multifunctionality in terrestrial ecosystems.
The explosive-effusive transition within the Fataga suite, Gran Canaria
Authors: Baumann Nils Björn , Ellis Ben , Cortes-Calderon Edgar Alejandro , Bachmann Olivier , Harris Chris , Szymanowski Dawid
Published: March 2022

Most volcanoes, across tectonic settings, can show both explosive and effusive eruptions, either as separated eruptive events or within the same eruptive episode. Such differences in eruptive style have significant implications for depositional morphology and hazards associated with the eruptions. In many cases, chemically nearly identical magmas may produce either explosive or effusive events. In contrast, we find the intercalated ignimbrites and lavas of trachytic to phonolitic compositions of the Fataga Group, Gran Canaria, differ markedly in several aspects. First, field observations revealed that the lavas pinch out toward the caldera rim and are therefore likely originated from extra-caldera sources. Second, while the explosive deposits vary in crystallinity (here referring to crystals with a long axis > 250 µm) from a few percent in crystal-poor portions to 10 – 20% in crystal-rich clasts, the lavas are almost aphyric with crystallinities < 1%. Further, while the ignimbrites have a mineral assemblage containing alkali-feldspar, biotite, pyroxene, amphibole, titanite, and Fe-Ti oxides, the lavas mostly contain alkali feldspar as a nearly unique mineral phase. Third, major elemental compositions show that while ignimbrites and lavas may overlap within the trachyte field on a TAS plot, only the lavas have compositions that extend to phonolite. Trace elemental compositions of lavas suggest extensive fractionation with compatible elements (e.g. Ba, max 227 ppm, avg. 30 ppm) depleted and incompatibles (e.g. Zr, Hf, Ce, Rb) enriched. While crystal-poor juveniles from the ignimbrites may have compositions approaching those of the lavas, crystal-rich juvenile clasts are markedly enriched in feldspar-phyric elements (e.g. Ba, max 1892 ppm, avg. 1496 ppm) suggesting involvement with a feldspar-dominated cumulate pile. Furthermore, CIPW norm calculations show that the lavas trend towards nepheline-normative compositions. The normative prediction of nepheline occurrence in the lavas is confirmed by petrographic observation of nepheline both as groundmass constituent and rarely as phenocrysts and thus suggests a somewhat different petrogenetic history for the lavas. Fourth, on a crystal scale, the feldspar phenocrysts in the lavas have relatively restricted, and low Ba contents (20 - 500 ppm), while ignimbrites have extremely Ba-enriched feldspars (up to 18,000 ppm Ba) in their crystal-rich portions.

Deposit geometry, petrography, and geochemical data lead us to the conclusion that the Fataga lavas must have followed a different petrogenetic path than their explosive counterparts. We, therefore, suggest the magmas feeding the effusive eruptions may have bypassed the main caldera system and thus provide a different window into the Miocene magmatism of Gran Canaria.
Relative roles of different key forcing and preconditioning factors for recurrent deep convection in the Labrador Sea from observations and ocean models
Authors: Handmann Patricia , Yashayaev Igor , Schwarzkopf Franziska
Published: March 2022

The Labrador Sea in the subpolar North Atlantic is one of the few special regions, where strong wintertime buoyancy loss, consecutive substantially reduced vertical stratification, and the prevailing circulation facilitate the transfer of water mass properties from the surface to depths exceeding 1500 m through deep convective mixing. Hence, impacting the characteristics of the intermediate and deep waters in the entire Atlantic basin. Despite ever-growing evidence of the freshwater and atmospheric gas contents of these waters being directly affected by the strength of wintertime mixing in the Labrador Sea, the relative importance of the Labrador Sea convection for the strength of the overall Atlantic meridional overturning is still under debate, often leading to contradicting conclusions. This ongoing debate highlights the need for an in-depth all-inclusive investigation of the processes responsible for both occurrence and persistence of deep convective mixing events. Here, we make a first step in this direction by aligning multiplatform observations with model runs and quantifying the roles of the local atmospheric forcing (e.g., cumulative wintertime air-sea flux), the remote oceanic forcing (e.g., horizontal advection) and the ocean’s own memory of the past convective events (e.g., weak stratification resulting from convective preconditioning).

These three key factors, fully responsible for initiation and undergoing of winter convection, and both seasonal and interannual heat content changes in the Labrador Sea, are analyzed based on long time series. These are comprised from all available thoroughly quality-controlled ship, profiling float and mooring measurements in the central Labrador Sea and state-of the-art ocean models. The resulting variables compared between the observations and models include time series of the characteristic ocean state variables, such as temperature, salinity and density over the entire water column. Additionally, the variables quantifying specific outcomes of each winter convection, such as depth, density and volume of the newly mixed intermediate-depth water in the Labrador Sea are considered. 

We show that the seasonal evolution of the deep winter convective mixed layer is a result of the sum of the surface cooling and the overall multiyear inertia in density changes and variations in the heat, freshwater and salt imports from the neighboring North Atlantic and Arctic regions. This, in turn means that not forcibly the strongest surface cooling induces the deepest convection with maximum density water, but rather a combination of the three factors. Through the combined analyses of observations and model-based time series we are able to properly assess the relative contribution of these three factors to the development of deep convective mixing in the Labrador Sea.
How to discover ancient stress-levels preserved within fractures using the stress-memory effect of specific stiffness
Authors: Kluge Christian , Muhl Lena , Schramm Daniel , Blöcher Guido
Published: March 2022

Stress changes have a large impact on the hydraulic and mechanical properties of fractures and can be caused by varying the fluid pressure in a subsurface reservoir or by tectonic movements. Innovative tools to assess the stress conditions are still of major importance for most subsurface applications. We derived an experimental procedure to reveal stress signals preserved in fractures in the laboratory.

In a set of complex experiments various fractured low-permeability rocks, two sandstones and two crystalline rocks, were cyclically loaded in a MTS tri-axial compression cell. The preconditioned cylindrical samples were split into two halves to generate an artificial tensile fracture and a rigid shear displacement was applied before installing the sample into the apparatus. Two different loading scenarios were applied: “continuous cyclic loading” (CCL) and “progressive cyclic loading” (PCL). During continuous cyclic loading samples were loaded from 2 to 60 MPa in several repeated cycles. In the progressive cyclic loading experiments the hydrostatic confining pressure was increased using a step-wise function (15, 30, 45 and 60 MPa) and was unloaded after every sub-cycle, while the pore pressure was kept constant at a low level. The mechanical fracture closure was monitored continuously during the experiments using axial and circumferential extensometers and the specific fracture stiffness could be calculated at a very high resolution. The fracture permeability was measured continuously using four high-pressure fluid pumps. A 3D surface scanner was used to analyze the fracture surface geometry before and after the experiments to reveal possible changes to the surface topography as well as to quantify changes in aperture and contact-area ratio.

The specific fracture stiffness was shown to be irreversible when a fracture was hydrostatically loaded once. Further, a “stress-memory” effect of fracture stiffness could be shown during progressive loading. It is characterized by a change from non-linear to linear stiffness evolution when a previous stress-level is exceeded. This phenomena can be used to identify previous stress states preserved within fractures. Additionally, this data is important for elasto-plastic contact theories of rough fractures. The impact of progressive loading on fracture permeability evolution showed varying results based on the heterogeneity and mineral composition of each rock type and the resulting fracture geometry.