bluuebunny/crossref_metadata_2025 huggingface dataset:
Hypersensitivity of Southern Ocean air-sea carbon fluxes and biological productivity to turbulent diapycnal fluxes
Authors: Ellison Elizabeth
Published: March 2022

The Southern Ocean (SO) connects major ocean basins and hosts large air-sea carbon fluxes due to the resurfacing of deep nutrient and carbon rich waters, driven by strong surface winds. Strong vertical mixing in the SO is induced by breaking waves excited by strong surface winds and interaction of tides, jets and eddies with rough topography. Vertical mixing has primarily been considered of importance for biogeochemical cycles due to the role of mixing in setting the underlying dynamics of the meridional circulation on a centennial timescale. Using an eddy-permitting ocean model that assimilates an extensive array of observations, we show that altered mixing can cause up to a 40% change in SO air-sea fluxes in only a few years by altering the distribution of dissolved inorganic carbon, alkalinity, temperature and salinity. Biological productivity is also highly altered, with strong regional and seasonal variations in the sensitivity and response to enhanced mixing. This altered biological productivity could lead to alterations in the biological carbon pump over longer time scales. The high sensitivity of carbon fluxes and biological productivity shown over short time scales is due to high vertical gradients in nutrients, DIC, alkalinity and temperature found in the upper waters of the SO. Further carbon flux and other biogeochemical observations are to better constrain the rates of vertical mixing from observations. Vertical mixing processes are unresolved in climate models, yet essential for the modelling of SO carbon cycles.
GRACE-FO Science Results and Mission Status
Authors: Flechtner Frank , Landerer Felix , Save Himanshu , Mccullough Christopher , Dahle Christoph , Bettadpur Srinivas , Watkins Michael , Snopek Krzysztof , Gaston Robert
Published: March 2022

The Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission has collected nearly 4 years of monthly gravity and mass change observations since its launch in May 2018. On March 17 we have celebrated the 20th anniversary of the GRACE launch. The combined GRACE/GRACE-FO mass change data record is therefore now spanning exactly two decades, and is an essential tool to quantify and track Earth’s water movement and surface mass changes across the planet. Monitoring changes in ice sheets and glaciers, near-surface and underground water storage, the amount of water in large lakes and rivers, as well as changes in sea level and ocean currents provides an integrated global view of how Earth’s water cycle and energy balance are evolving.

In this presentation we will update the community on the current GRACE-FO mission status and near-term plans, including instrument and flight system performance (i.e., satellite health status and outlook, performance of precise inter-satellite ranging from the K/Ka band and Laser Ranging Interferometers, and accelerometry as processed at Jet Propulsion Laboratory (JPL), the official Level-1 data analysis center). We will discuss the GRACE-FO science data quality, reprocessing plans, and highlight recent science results, discoveries, and applications. Finally, we will conclude with a short outlook towards achieving continuity with future mass change missions.
Rare earth elements as potential tracers of carboxylate-based plant nutrition strategies 
Authors: Wiche Oliver , Pourret Olivier , Lambers Hans
Published: March 2022

Phosphorus (P) and iron (Fe) are limiting nutrients in many (agro-)ecosystems. Due to P-sorption under most soil conditions, the current P-fertilization practices are inefficient, since large quantities of the P fertilizer applied remain in the soil as a residual part. Therefore, the development of sustainable agricultural practices urgently needs to improve nutrient-acquisition efficiencies of crop species through rhizosphere engineering and breeding of low-input strains. The availability of nutrients in the rhizosphere, especially that of P, is dependent on the activity of roots and associated microbes, particularly their ability to acidify the surrounding soil and release chelating compounds such as carboxylates. Therefore, there is a growing interest among plant ecologists, breeders and agronomists in “easily-measurable” tools to trace belowground functional traits in nutrient acquisition under soil conditions. Here, we explore the idea to use rare earth elements (REEs) in plant material to evaluate the nutrient-acquisition strategy, particularly under nutrient limitation. The rationale behind this hypothesis is that i) REEs are present in almost all soils at quantities similar to some plant nutrients such as Cu and Zn, ii) REEs interact with nutrient-bearing soil phases (phosphates, Fe-oxyhydroxides), iii) root exudates released under P/Fe deficiency strongly mobilize REEs in soil, and iv) the uptake of mobilized REEs in plants depends on their chemical form, which is a function of rhizosphere chemistry.  Preliminary results from greenhouse and large-scale field experiments indicate that P-inefficient species show different REE-concentrations in their leaves than P-efficient species, and that the pattern of REEs is related to the composition of root exudates. In ongoing experiments, this hypothesis will be rigorously tested by coupling a field sampling campaign of plant material from species with contrasting nutrient-acquisition strategies along soils with changing nutrient availability (Western Australian chronosequences) as well as controlled greenhouse experiments for mechanistic elucidation of processes involved.
Ecohydrological characterization of the karst groundwater dependent ecosystems of the Dinaric karst in Slovenia
Authors: Ravbar Natasa , Pipan Tanja
Published: March 2022

Karst groundwater dependent ecosystems (KGDEs) represent an important asset worldwide due to their ecological and socioeconomic values. Although they are increasingly recognized as such, they have not been adequately documented and studied. The present contribution aims at characterizing the main KGDEs of the Dinaric karst in Slovenia. Their classification is based on their position within the hydrological system, geomorphology and ecological settings The main hydrological processes (i.e., extent, duration and frequency of groundwater inflow), the main biota and indicator communities, and the factors limiting the evolution of species (e.g., darkness) were identified. An overview of rare, endemic and charismatic species was also shown including Proteus anguinus, Marifugia cavatica, Monolistra racovitzae racovitzae and others. Due to its location in an area of very high geographical diversity and between different climate types, the Slovenian Dinaric karst is one of the hotspots of subterranean biodiversity on a global scale. The interaction between orographic, climatic, hydrological and edaphic conditions, as well as the fact that the area served as a hub for different species and as a refuge during the ice ages, are crucial for the very high biodiversity in this area. Due to deforestation in prehistoric times, man has even contributed to the diversification of the flora by creating space for the appearance or spread of habitats that are now considered natural (e.g., dry grasslands). An important factor in maintaining a particularly rich diversity of karst flora and fauna is also the low human impact and the very well preserved landscape in its natural state. KGDE sites in Slovenia with the greatest known species diversity are the Postojna-Planina and Škocjanske Jame cave systems, Cerkniško and Planinsko Polje, and the intermittent lakes of Pivka. Characterization of KGDEs is a prerequisite for a better understanding of the processes that control them, their biological function, and their vulnerability. Based on knowledge of how they will change and adapt under current pressures and global challenges from climate, land use, and societal changes, appropriate protection can be built. The ecohydrological characterization of KGDEs of Slovenian Dinaric karst presented here can serve as a pilot study for other karst regions with high biodiversity.
Ground-based HDO and SO2 thermal mapping on Venus : An update
Authors: Encrenaz Therese , Greathouse Thomas , Giles Rohini , Widemann Thomas , Bézard Bruno , Fouchet Thierry
Published: March 2022

Since 2012, we have been monitoring SO2 and H2O (using HDO as a proxy) at the cloud top of Venus, using the TEXES high-resolution imaging spectrometer at the NASA InfraRed Telescope Facility (IRTF) at Maunakea Observatory. Maps have been recorded around 1345 cm-1 (7.4 microns), where SO2, CO2 and HDO are observed, and around 530 cm-1 (19 microns) where SO2 and CO2 are observed. An anti-correlation has been found in the long-term evolution of these two species and SO2 plumes have been identified with an evolution time scale of a few hours. The SO2 distribution as a function of local time seems to show two maxima around the terminator, indicating the possible presence of a semi-diurnal wave (Encrenaz et al. A&A 639, A69, 2020). After a year of interruption due to the Covid crisis, new observations have been performed in July and September 2021.   They show that the SO2 abundance, which had been globally increasing from 2014 until 2019, has now decreased with respect to its maximum value. The new data will be analyzed in the context of the whole dataset.
Effect of horizontal airflow filtering using a porous cylindrical shroud on vertical turbulence characteristics
Authors: Abdoli Mohammad , Schneider Johann , Olesch Johannes , Thomas Christoph
Published: March 2022

This paper presents the findings of a series of experimental studies to investigate the variation of vertical flow characteristics after filtering horizontal flow using porous cylindrical shrouds. Exploring this research question implies improving the existing method of observing horizontal wind speed and direction using Distributed Temperature Sensing (DTS) to develop it for the vertical direction to capture continuous and distributed turbulence. The experiments were performed using two sonic anemometers and two pressure ports in the open experimental area; one of each sensor is located inside the cylindrical shroud. The flow statistics were compared between different shroud configurations with different shapes, colors, rigidity, and porosity. Based on the coefficient of determination and mean error between shrouded and unshrouded data, the white insect screen shroud with a rigid structure and 60 cm diameter and 145 cm height is determined as the most conducive setup. The optimum shroud setup reduces the horizontal wind standard deviation by 35 percent, having a coefficient of determination of 0.972 between vertical wind standard deviations and RMSE less than 0.018 m/s between shrouded and unshrouded set up. However, the comparisons confirm that the vertical flow remains unaltered while reducing the horizontal flow, but the spectral energy ratio between the shrouded and unshrouded setup shows different responses. This ratio decreases exponentially in the high frequencies, which means the shroud damps the high-frequency eddies with a temporal scale of fewer than 6 seconds. Despite high frequencies, the ratio remains constant in the low frequencies for all energy spectrums, including temperature, wind components, momentum, and sensible heat flux.
Deep mass redistribution prior to the Maule earthquake revealed by GRACE satellite gravity
Authors: Bouih Marie , Panet Isabelle , Remy Dominique , Longuevergne Laurent , Bonvalot Sylvain
Published: March 2022

The control on megathrust earthquake generation exerted by deeper subduction processes remains poorly understood and still insufficiently documented. Here, we use the 2003-2014 space-time variations of the Earth’s gravity gradients derived from the GRACE geoids in order to probe aseismic mass variations at depth and their possible interactions with intraplate seismicity along the Chilean margin. We work with three different datasets of GRACE geoid models over a large region surrounding the rupture zone of the Mw 8.8 2010 Maule earthquake. In order to separate signals associated with mass sources of differents sizes, shapes or orientations, we reconstruct each month the Earth’s gravity gradients at different spatial scales from these geoid models. Our analysis emphasizes a highly anomalous, large-amplitude gravity gradients signal that appears three months prior to the earthquake North of the epicentral zone, and progressively increases until the megathrustal rupture, in all three datasets. We show that this large signal cannot be caused by a shallow hydrological source nor by GRACE striping artefacts and dealiasing models. Instead, we conclude that its most likely origin is in mass redistributions within the solid Earth on the continental side of the subduction zone. These anomalous gravity gradient variations could be explained by a deep extensional deformation of the slab around 150-km depth along the Nazca Plate subduction direction, driving large-scale fluid motion in the subduction zone and into the overriding lithosphere. Our results highlight the importance of observations of the Earth’s time-varying gravity field from satellites to probe aseismic mass redistributions in-depth major plate boundaries . The detection of such mass redistributions at depth by GRACE and their interactions with interplate seismicity opens a new field of research to better characterize and understand the dynamics of the seismic cycle at megathrusts.
A station-based evaluation of south foehn forecasting with COSMO-1
Authors: Tian Yue , Schmidli Juerg , Quimbayo-Duarte Julian
Published: March 2022

This study investigates the skill of the COSMO model (v5.7) at 1.1 km horizontal resolution (COSMO-1) in simulating the near-surface foehn evolution, with a focus on surface temperature, for a set of five south foehn events and a 5-year-long analysis dataset based on COSMO-1. A significant cold bias during foehn hours is found in the Rhine Valley as well as other northern Alpine valleys for all five cases and the 5-year climatology. Several possible causes of the cold bias are examined using sensitivity experiments for the five foehn cases. The sensitivity experiments include changes to the parameterization of the land-atmosphere interface (i.e. adoption of a skin temperature, a change of the heat resistance in the laminar sublayer, and a new formulation of the bare soil evaporation), to the 1D turbulence parameterization (including horizontal shear production of turbulence as a first step towards 3D effects), and to the horizontal grid spacing (1.1 km versus 550 m). While several of the sensitivity experiments impact the 2-m temperature during non-foehn hours, only a change in the horizontal grid spacing has a significant impact on the 2-m temperature during foehn hours. The 550-m run shows also an improvement in the simulated foehn duration and northward foehn extent. Possible reasons for the improvements and the remaining bias will be discussed.
Sedimentation-driven cyclic rebuilding of gas hydrates
Authors: Schmidt Christopher , Gupta Shubhangi , Burwicz-Galerne Ewa , Wallmann Klaus , Hartz Ebbe H. , Rüpke Lars
Published: March 2022

Gas hydrate recycling is an important process in natural hydrate systems worldwide. The recycling of hydrates often leads to high hydrate saturation close to the base of the gas hydrate stability zone (GHSZ). However, to date it remains enigmatic how free gas is recycled back into the GHSZ and what the controlling factors are. Here we use a 1D compositional multi-phase flow model to investigate the dominant mechanisms that control natural gas hydrate recycling. As case study, we apply the numerical model to study hydrate recycling at the Green Canyon Site 955 in the Gulf of Mexico, where high sedimentation rates are thought to drive vigorous hydrate dissociation and re-invasion of free gas into the stability zone. Our novel results suggest that hydrate recycling is a highly dynamic process in which hydrates form and dissociate at surprisingly rapid rates with an inherent cyclicity. These cycles can be divided into three phases of 1) gas accumulation phase, 2) gas breakthrough phase and 3) uninhibited hydrate build-up phase. During the first phase hydrates are dissociating and free gas accumulates below. After the free gas saturation reaches a threshold value (given by the mutual effects of entry pressure, bulk permeability, and relative permeability function), gas breaks through the barrier of the remaining hydrate layer. Controlled by permeability and kinetic rate a new hydrate layer forms.  In the absence of external perturbations to the GHSZ, gas migration leads to a distinct hydrate layer with a convex distribution of hydrate saturation. Such a hydrate layer acts like a converging-diverging `nozzle' for the gas flow, when gas enters the hydrate layer, it decelerates until it reaches the peak hydrate saturation (i.e. the nozzle throat), and then accelerates until it exits the hydrate layer on the other side. This nozzling effect, together with the hydrate dissociation kinetics, leads to the cyclic behavior of hydrate recycling. We suggest that the evident cyclicity of burial-driven gas hydrate build-up process provides a new advanced understanding of natural gas hydrate recycling process, and free gas invasion mechanisms into the GHSZ.
Subpolar gyre decadal variability explains the recent oxygenation in the Irminger Sea
Authors: Feucher Charlene , Portela Esther , Kolodziejczyk Nicolas , Thierry Virginie
Published: March 2022

The North Atlantic is one of the hot-spot for ocean oxygen ventilation due to cold surface water and strong winter convection. This region is subjected to large interannual to multidecadal variability, which is suspected to strongly impact the regional and temporal oxygen ventilation and inventory.
Here we investigate the oxygen variability over 1991-2018 and driving mechanisms of the two main water masses of the Irminger Sea: the Labrador Sea Water (LSW) and the Island Scotland Overflow Water (ISOW). For this, we combined the most recent Argo dataset with ship-based hydrographic data in the Irminger Sea. The dissolved oxygen concentration of the LSW oscillated between 300 mu mol/kg in the early 90's and between 2016 and 2018, and 280 mu mol/kg in the period 2002-2015. The temporal changes in oxygen concentration are less pronounced in the underlying Iceland Scotland Overflow Water (ISOW).
We show that, while solubility changes partly explain the variability of the dissolved oxygen concentration within the Labrador Sea Water (LSW), the main driver of oxygen variability is the Apparent Oxygen Utilisation (AOU). 
In the early 90's and between 2015 and 2018, the deep convection was more intense and led to less stratified, thicker, colder, and more oxygenated LSW than during the period 1995-2015. This was attributed to larger ocean heat loss, stronger wind stress, and colder subpolar gyre under positive NAO conditions.   
The observed oxygen variability in the Irminger Sea between 1991 and 2018 does not show any significant linear trend. This study provides the first observational evidence of the impact of the subpolar gyre decadal variability on the oxygen ventilation in the Irminger Sea and advocates for continuing the monitoring of oxygen concentration and content in the subpolar gyre to separate any possible warming-induced long-term changes from the large decadal natural variability.
Mechanisms of in-situ remediation of soil with lead and sulfate contaminants using multiple binder strategies: experimental and numerical studies
Authors: Liu Yikai , Molinari Simone , Dalconi Maria Chiara , Bellotto Maurizio Pietro , Valentini Luca , Ferrari Giorgio , Pellay Roberto , Salviulo Gabriella , Artioli Gilberto
Published: March 2022

Solidification/stabilization (S/S) is a versatile process used in contaminated soil remediation. The development of green binders and the associated immobilization mechanisms is imperative to the remediation research due to the aggravated carbon/energy footprints of the widely employed ordinary Portland cement (OPC). In this work, a pyrite ash disposal site, where the soil has high lead and sulfates contents, was selected for lab-scale tests and the following in-situ field trials. Traditional binders (OPC and cement III/B) and alternative binders (calcium aluminate cement, mayenite-blast furnace mix, and alkaline-activated blast furnace slag) were preliminarily applied using the high-performance S/S pelletization treatment (HPSS©). Systematic mineralogical and microstructural characterization and pH-dependent leaching tests were applied to investigate the S/S effectiveness of different scenarios. Subsequently, simulations were developed to identify the minerals controlling the leaching behavior of stabilized pellets. Overall, the proposed methodology is a pertinent tool for extrapolating the contaminated soil HPSS© to realistic conditions.
Seismic Intensity Estimation using Machine Learning for on-site Earthquake Early Warning (EEW)
Authors: Bae Sungmyung , Choi Yonggyu , Song Youngseok , Byun Joongmoo , Seol Soon Jee
Published: March 2022

Earthquake Early Warning System (EEW) is a technology that calculates earthquake parameter using P-wave that arrives earlier and warns the expected damage area before the arrival of destructive S wave. Therefore, many countries are operating EEW to mitigate damage from earthquake shaking. Especially an on-site EEW is drawn attention as it can reduce blind zones due to using only a single or minimum station. In the on-site EEW, it is important to quickly predict the seismic intensity, which indicates the degree of ground damage, response of structures and ground shaking felt by people at a given location, rather than information on the magnitude or distance of the earthquake.

In this study, we suggest a machine learning (ML) model that can directly estimate the seismic intensity scale from initial P-waveforms of three-component acceleration data measured at a single station. We used 1D-Convolutional Neural Networks (1D-CNN), which have been shown good performance in signal processing of speech and medical data which are similar to earthquake signals. K-Net and KiK-net datasets, recorded at stations in Japan, were used for training the ML model. Since the amount of data is enough and all of data are labeled with Japan Meteorological Agency Seismic Intensity Scale (IJMA), the datasets were used as training data in this study. The developed model produced fast and accurate results using only the three-component acceleration field data at a single station.

In order to test applicability of the trained model to the new dataset acquired from other regions, the trained model was applied to the STEAD data which were recorded at stations distributed globally. When the trained model was applied to STEAD data directly, the prediction results were worse than those of K-Net and KiK-net data. The reason is that the characteristics of the ground and waveforms are different depending on the region. Therefore, to solve this problem, transfer learning was applied, and only the parameters of a fully connected layer of pretrained ML model were fine-tuned using small number of both labeled target dataset and training dataset used for pretraining. Moreover, by considering the imbalance problem of the training data for transfer learning, it was able to obtain better prediction results. Ultimately, this study shows the pretrained model with a specific region dataset can provide reasonable prediction of seismic intensity to new dataset acquired from other regions using transfer learning.
A hybrid methodology based on Neural Network and Change detection approaches and using Sentinel-1/Sentinel-2 for soil moisture estimation
Authors: Zribi Mehrez , Nativel Simon , Rodriguez Fernandez Nemesio , Baghdadi Nicolas , Madelon Remi , Albergel Clement
Published: March 2022

Soil moisture is an essential parameter for a better understanding of water processes in the soil-vegetation-atmosphere interface. In this context, passive and active microwave remote sensing have enabled the development of various increasingly operational approaches, in particular for low spatial resolution products. Synthetic aperture radar (SAR) is particularly suitable for monitoring water content at fine spatial resolutions of the order of 1 km spatial resolution. Since the launch of Sentinel-1 in 2014, numerous methodologies have been proposed for estimating fine spatial resolutions soil moisture, especially in agricultural areas. Two approaches are often considered in the inversion of SAR signals: approaches based on machine learning methodologies, such as neural networks trained on scattering models, or approaches based on change detection, essentially validated on low spatial resolution products using scatterometers. In this study, we propose a hybrid approach combining both the neural networks and change detection approaches. The methodology was applied to Sentinel-1 and Sentinel-2 using numerous predictors; Vertical-Vertical (VV) polarization radar signal, incidence angle, Normalized Difference Vegetation Index (NDVI) optical index, VH/VV ratio, etc.

This hybrid approach is tested on the database of the international soil moisture network (ISMN) with moisture networks covering different climatic contexts. Results are very encouraging with 10% improvement in the accuracy of soil moisture estimates compared to the use one of each approach individually (Neural Network or change detection).
A least-squares collocation approach to densifying river level from multi-mission satellite altimetry; Case study Mackenzie River basin
Authors: Saemian Peyman , Tourian Mohammad J. , Sneeuw Nico
Published: March 2022

Measuring river water level is essential for the global freshwater system monitoring, water resource management, hydrological model development, and climate change assessment. Despite its importance, the number of in-situ gauges has decreased over the recent decades. Moreover, many of the river systems are monitored either sparsely or not long enough to investigate their long-term evolution. Satellite altimetry is a unique technique that has enabled quantifying river levels for more than 25 years. Single mission altimetric water level time series can be obtained at the intersection of the satellite ground tracks and the river. For operational hydrology, however, single mission satellite altimetry is limited in its spatial and temporal sampling governed by the orbit configuration. This study proposes a framework to estimate the long-term sub-monthly river water level over the entire river using Least-Squares Collocation (LSC) by benefiting from multi-mission altimetric water levels (both interleaved and repeat orbit missions). The proposed method allows us to obtain dense water level observations both in time and space.  We present the results over the Mackenzie River basin, located in Canada, and validate against in-situ data.
A tool for scientific collaboration, reproducible analyses and interactive publications: FastResearch.io
Authors: Waldschläger Kryss , von Papen Michael
Published: March 2022

Our current era is often referred to as the 'age of data'. Increasing amounts of data and models are generated, often without being used sustainably - because they are not accessible, difficult to understand or difficult to transfer to other data sets. With https://envsci.fastresearch.io/, we aim to improve collaboration on data sets and analyses to make them usable and reproducible for everyone. With our innovative platform, we want to enable researchers to work together on data and data analysis by giving them a tool to collaborate and to make their data and analyses open access. On our platform, large amounts of data can be combined with extensive analyses and used either privately, partially publicly or completely publicly. With FastResearch.io, data and models will be easily accessible and usable even for non-specialists, as data are modularly exchangeable and users do not need to build their own environments to use the models. While a curated software environment is offered for R and Python, users can also use customized environments (docker images) due to the modular and containerized infrastructure, which allows coding in any programming language. The great advantage of FastResearch.io compared to other platform solutions is that data and analyses connected to these data are stored together within a working software environment, which ends consistency problems in collaborative projects forever.
Fluid features during hydrocarbon generation and expulsion from laminated source rocks
Authors: Wang Miao , Chen Yong , Matthew Steele-MacInnis
Published: March 2022

Bed-parallel, fibrous calcite veins are widespread within Eocene, lacustrine, laminated organic-rich source rocks in the Dongying Depression of Bohai Bay Basin, East China. Such veins mainly occur in the horizontal organic-rich laminae (composed of horizontal banded lamalginites) of mature source rocks, with higher TOC and lower carbonate contents than the adjacent non-vein sections vertically. They are products of diagenesis accompanying burial, and their formation was coeval with hydrocarbon generation and expulsion from the initial fracture opening and subsequent dilation, which was evinced by the occurrence of medium plane (calcite+bitumen) and primary hydrocarbon inclusions in the fibrous calcites. Petrographically primary two-phase (oil+gas) hydrocarbon inclusions, and coeval aqueous inclusions are distributed either within individual fibrous calcite grains or between two adjacent fibres. In rare cases, inclusions with only liquid hydrocarbons were observation. The hydrocarbon liquid shows various UV-fluorescence colours (brownish, yellow, yellow-green, green), indicating different composition of oil from less mature to relatively high maturity. The micro-spectrofluorimetry of yellow-green fluid inclusions contains the two dramatic peaks (511 nm and 568 nm) of yellow and green fluorescence, suggesting that it was the by-product by fractionation. In addition, many bitumen-bearing oil inclusions could also be observed in the fibrous calcite veins. Consequently, we surmise that immiscibility and heterogeneous trapping of liquid hydrocarbon, bitumen and aqueous solution during the fibrous calcite growth are the best explanation for these above features. The PVT calculation by use of isochores intersection of oil inclusions and aqueous inclusions, combined with study of the burial history show that veins were formed during the Oligocene Dongying sedimentary stage (32.8-24.6Ma). We conclude the fluid overpressure up to approximately twice (2x) the hydrostatic value (i.e., ~0.5–0.6x lithostatic) are the most common during the hydrocarbon generation and primary migration. The highest degrees of overpressure are recorded by the rare monophase petroleum inclusions. The resulting isochores of these highest density inclusions project to pressures that overlap with the lithostatic gradient. Thus, we contend that vein dilation in the absence of lithostatic fluid pressure suggested a primarily steady-state process, in which dilation was accommodated and offset by concomitant narrowing of the adjacent wall rock laminae. And this process was likely driven by dissolution of CaCO3 from adjacent wall rocks, coupled with the later reprecipitation of calcite into the nascent horizontal fractures.
Total ozone trends and variability at three northern high-latitude stations
Authors: Bernet Leonie , Svendby Tove , Hansen Georg , Orsolini Yvan , Dahlback Arne , Goutail Florence , Pazmiño Andrea , Petkov Boyan
Published: March 2022

Even though ozone-depleting substances have been substantially reduced due to the Montreal Protocol, it is still not possible to state with confidence that the total column amount of ozone (total ozone) recovers globally. A special focus lies on high latitudes, as they experienced strong stratospheric ozone depletion in the 1980s and 1990s. Especially at northern high latitudes, it is still challenging to detect significant total ozone trends. It is therefore important to use carefully homogenized and stable long-term ozone measurements and advanced trend models to derive ozone trends at northern high latitudes.

This study uses ground-based total ozone measurements in Norway and the Arctic to investigate total ozone trends at northern high latitudes. We present combined total ozone time series from Brewer Spectrophotometers at Oslo (60°N) and Andøya (69°N) in Norway, from 2000 to 2020. In addition, measurements from a SAOZ instrument and a Brewer at Ny-Ålesund in Svalbard are used. The combined Brewer time series consist of direct sun (DS) and global irradiance (GI) Brewer measurements and are complemented with measurements from ground-based ultraviolet radiometers (GUV). This makes it possible to obtain measurements during cloudy conditions and in winter and spring, where DS measurements cannot be retrieved due to large solar zenith angles and reduced direct sunlight.

We present total ozone trends at the three measurement stations using the LOTUS (Long-term Ozone Trends and Uncertainties in the Stratosphere) multilinear regression model. We test various explanatory variables and select a set of predictors to obtain the best possible regression fit. We found that besides the commonly used predictors QBO, ENSO, and solar cycle, tropopause pressure and stratospheric temperature are also important to improve the fit. We finally present annual total ozone trends and trends for different months at each station. Despite that the annual trends were generally found to be insignificant, we detected significant trends in some months.

We believe that our study contributes to a better understanding of long-term ozone changes at northern high latitudes, which is essential to assess how Arctic ozone responds to changes in ozone depleting substances and to climate change.
Determining key drivers of the annual carbon budget of biocrusts in different climatic zones
Authors: Ma Yunyao , Weber Bettina , Raggio Quílez José , Colesie Claudia , Veste Maik , Bader Maaike , Porada Philipp
Published: March 2022

Biocrusts are distributed over all climate zones of the world and they substantially contribute to ecosystem functioning. Their growth, determined by their carbon balance, can be affected by various climatic drivers. The effects of individual drivers are clear from laboratory experiments, but the relative importance of different drivers along climatic gradients and their underlying mechanisms are largely unknown. Moreover, the effects of seasonal acclimation on the annual carbon balance are not fully understood either. Therefore, we aim at determining the level and variation of annual biocrust carbon balances and their connection to climatic drivers along environmental gradients. In addition, we explore the role that acclimation plays in the carbon balance of biocrusts.

Here, we applied a data-driven model at six study sites along climate gradients and performed several sensitivity analyses to investigate the most relevant factors for the annual carbon balance, including impacts of acclimation of traits. The model was developed using a physiology-based photosynthesis model, and the necessary parameters were obtained from field and laboratory measurements.

We found a consistent set of control factors under different climate conditions, namely radiation, relative humidity, surface temperature, and ambient CO2 concentration, which were of roughly equal relevance. However, the effect of relative humidity on the carbon balance depended on the habitat’s microclimate, and a reduction in non-rainfall water sources resulted in more carbon loss in drylands but fostered carbon gain in humid environments. In addition to climate factors, the seasonal acclimation of traits played an essential role in the annual carbon balance at humid sites. Thereby, not accounting for acclimation processes in models of biocrusts may be a potential explanation for estimated negative carbon balances in humid regions.

Our results suggest that global change, which may lead to warmer and drier air in some regions, will likely affect biocrust long-term carbon balances. Moreover, for experimental investigations, the season and timing of collecting and monitoring the species should be given additional consideration, especially when the traits are used as the basis for quantitative estimates and forecasts.
Hydroclimate Elasticity of Accessible Water
Authors: Thomas Brian
Published: March 2022

Terrestrial water response to climate-induced acceleration of the hydrologic cycle underpins water management challenges, whereby water management in an increasingly uncertain climate must adapt to ensure sufficient resource availability to sustain global ecosystems while meeting societal water needs. Although hydrologic cycle intensification is expected through increased evaporation and precipitation, the unequal redistribution of water fluxes over terrestrial land remains unclear. Studies investigating hydroclimatic sensitivity of runoff assumed long-term steady-state basin storage conditions where P=ET+Q.  Steady-state assumptions neglect the role of groundwater, lakes and reservoirs as vital management resources.  Although hydrologic models have been used to measure sensitivity of basin responses attributed to climate, an assessment of observation-based data which captures temporal changes in basin storage can provide valuable insights to understand fundamental changes in water storage due to hydroclimatic factors.  Here, a sensitivity analysis using the Gravity Recovery and Climate Experiment (GRACE) satellite observations combined with auxiliary hydroclimate variables is investigated.  GRACE captures changes in water stores that result due to water management schemes to offset short-term (i.e., monthly) and long-term (i.e., annual) water deficits in addition to water budget changes driven by P and ET.  Accessible water (AW) represents the combination of groundwater and surface water storage anomalies derived from GRACE, water stores deemed accessible to fulfill water demands.  Results document the role of seasonality and storage potential with respect to hydroclimate elasticity.  Findings reveal that >1 billion people live in basins with elasticity magnitudes >10, meaning that small shifts in P-ET will be magnified 10-fold with respect to AW.
Development of air quality boxes based on low-cost sensor technology
Authors: Gäbel Paul , Koller Christian , Hertig Elke
Published: March 2022

Analyses of the relationships between climate, air substances and health usually concentrate on urban environments due to increased urban temperatures, high levels of air pollution and the exposure of a large number of people compared to rural environments. Ongoing urbanization, demographic aging and climate change lead to an increased vulnerability with respect to climate-related extremes and air pollution. However, systematic analyses of the specific local-scale characteristics of health-relevant atmospheric conditions and compositions in urban environments are still scarce due to the lack of high-resolution monitoring networks. In recent years low-cost sensors became available, which potentially provide the opportunity to monitor atmospheric conditions with a high spatial resolution and which allow monitoring directly at exposed people.

We develop a measurement system for several air substances like ozone, nitrogen oxides, carbon monoxide and particulate matter as well as meteorological variables like temperature and relative humidity, based on low-cost sensors. This involves the assembly of compact, weatherproof boxes with 3D-printed parts. They contain a control unit based on Arduino hardware to gather the sensor data as well as self-designed printed circuit boards (PCBs). A Pycom microcontroller is used for low-power, high-temporal data transmissions by Long-Term Evolution Cat-M1 (LTE-M). These Atmospheric Exposure Low-cost Monitoring units (AELCM) include digital and analogue sensors for air substances and meteorological variables, LCD display, RTC module, uninterruptible power supply, active ventilation, a SD Module as a data black box in addition to an optional internally running FTP server and optional GPS module. A computational fluid dynamics (CFD) simulation is used to evaluate the air flow inside the AELCM units. Sensors are selected based on own analyses as well as according to evaluation and performance in other projects. The measurement equipment is extensively tested using the high-quality measurement unit for meteorology and air substances (Atmospheric Exposure Monitoring System, AEMS) of our research group, located at the Augsburg University Hospital.
Biological soil crusts as a mechanism to protect areas under sandization processes in southern Brazil
Authors: webber carla Lisiane , Werner Vera Regina , Seitz Steffen , Scholten Thomas , Bremer Ulisses Franz
Published: March 2022

Biological Soil Crusts (biocrusts) are communities of algae, lichens, mosses, cyanobacteria, and other nonvascular organisms living in the soil surfaces. Biocrusts are a key factor in the protection of arid and semiarid ecosystems and, therefore, playing a major role against desertification. Biocrusts are also of profound importance in sand dune areas, as they are recognized as the first colonizers after environmental disturbances and can help preventing sediment remobilization. Moreover, biocrusts have shown to be of importance in soil protection against erosion, but also nutrient cycling in the Pampa biome in Brazil. Here, natural geomorphological processes and soil misuse led to the expansion of sediment remobilization areas, generating a severe problem - the difficulty of fixing field vegetation and crops. The present study investigates the behavior and interrelationships of biocrusts specifically in areas that suffer sandization in the Brazilian Pampa biome and verifies their relationship with soils and soil organisms. We analyzed biocrusts in three consecutive stages. Starting with a taxonomic exploration of the dominant component of cyanobacteria, proceeding to its characterization and finally determining its importance. We investigated two study sites in São Francisco de Assis and samples were collected in May 2016 and October 2019. The sites are characterized by sandy soils that suffer gullying, one without human intervention and the other one with artificially stabilized ravines. The analysis of biological material was carried out with microscopy, and it could be determined that the composition consists of 13 taxa of cyanobacteria and one filamentous species, Stigonema sp., could be specifically highlighted. These black to dark green spotty communities on the soil surface played an important role in particle aggregation, which can be granulated and show macroscopic forms. When analyzing the location of the biocrusts within the topography, it was observed that they occur in more humid places, occupying the same positions in all relief compartments. Biocrusts mostly develop on the top of the gullies or on upper and more stabilized slopes, especially when facing southern orientation. Taking into account the biocrust cover, we can identify different morphologies such as smooth, rolling and pinnacle blocks, which showed us different combinations according to the degree of evolution related to the micromorphology of the relief. We found that the presence of these biocrusts as an element of nutrient source and balance generator can lead to a reduction of soil erosion and was thus of outmost importance for the restoration of this biome.
Dynamical and biogeochemical responses of the South Senegalese Upwelling System to synoptic wind variability: a modeling approach
Authors: Chabert Pierre , Capet Xavier , Echevin Vincent , Lazar Alban
Published: March 2022

In addition to the wind seasonal cycle, Eastern Boundary Upwelling Systems undergo intraseasonal fluctuations. These synoptic fluctuations are characterized by an intensification or a relaxation of upwelling favorable winds of a period of about 10 days and are believed to have a major impact on the upwelling dynamics. Here we focus on the South Senegalese Upwelling System (SSUS) which is located south of the sharp Cape Verde peninsula which acts as an abrupt coastline break and has a particularly shallow continental shelf. Previous studies described not only the SSUS climatological dynamics but also the importance of synoptic events that play a major role in the observed variability. However, their precise impacts on the 3D dynamics on the shelf remain unclear and consequences on biogeochemistry are unknown. We identify the key dynamical and biogeochemical processes of the coastal ocean in its response to synoptic events. This is done using a modeling experiment that consists in applying idealized synoptic wind intensification and relaxation to climatological SSUS states (with CROCO-PISCES). We find that synoptic fluctuations affect the regional circulation and shape robust anomalies of temperature, boundary layer depth, sea surface height,  surface and subsurface currents. Nutrients supply in the euphotic layer is significantly affected by synoptic fluctuations (+-30%). We find asymmetrical responses in nitrate, iron and silicate concentrations both between intensification and relaxation and between the inner and outer shelf regions. Persistent nitrate depletion is observed over the inner shelf. Phytoplanktonic ecosystem response to synoptic wind intensification thus differs spatially, with enhanced development of diatoms over the outer shelf and of nanophytoplankton over the inner shelf. Consequences on the zooplanktonic ecosystem are observed with a time delay and space shift, consistent with typical prey - predator relationships. Processes at play in the nutrients supply and planktonic ecosystem structure in response to synoptic fluctuations are discussed. 
Bare-earth DEM generation from ArcticDEM, and its use in flood simulation
Authors: Liu Yinxue , Bates Paul , Neal Jeffery
Published: March 2022

Terrain representation is important in many fields including flood mapping. In urban areas, topography data without ground objects are preferred in flood simulation for multiple concerns. However, the topography data collected by remote sensing techniques all contain the artefacts height to some extent. High-resolution photogrammetry DEMs, like ArcticDEM, are emerging with the widely available possibility while approaches to generate bare-earth DEM from them has yet been fully investigated. In this paper, we used the city of Helsinki as a case study. The optimal filter was selected among two morphological filters (PMF, SMRF) and then was used to generate bare-earth ArcticDEM with its various parameter combinations, generating a filtered ArcticDEM ensemble. Then, the elevation error and the flooding performance for a pluvial flooding scenario of this ensemble were evaluated at 2 m and 10 m resolution, respectively, using the LIDAR DTM as the benchmark. The SMRF was found to be advantageous over PMF and be effective at removing artefacts with broad parameter range. In the optimal ArcticDEM-SMRF the RMSE was reduced by up to 70%, achieving 1.02 m, and the simulated water depth error was reduced to a comparable magnitude expected from the LIDAR DTM simulation of 0.3 m. This paper indicates that the SMRF can be directly applied to generate bare-earth ArcticDEM in urban environment although caution should be taken when using in areas with densely packed buildings or vegetation. The results imply that the high-resolution photogrammetry DEMs have the potential to be an alternative of LIDAR in the future.