bluuebunny/crossref_metadata_2025 huggingface dataset:
How drought events during the last Century have impacted biomass carbon in Amazonian rainforests
Authors: Yao Yitong , Ciais Philippe , Viovy Nicolas , Chave Jerome , Joetzjer Emilie
Published: March 2022

During the last two decades, droughts have recurrently impacted the Amazon forests, as in the severe drought events of 2005, 2010 and 2015/16. The analysis of forest inventory plots suggests that these droughts have resulted in a reduction of the carbon sink of intact forests by causing mortality to exceed growth. Process-based models have struggled to include drought-induced responses of growth and mortality, and have not been evaluated against plot data. In this study, we use ORCHIDEE-CAN-NHA, a DGVM which includes modules of forest demography with different tree size cohorts dynamically influenced by growth, self-thinning from light competition and recruitment, a detailed tree hydraulic architecture function of each tree cohort, and drought-driven mortality due to the loss of tree conductance to simulate the impact of drought on biomass dynamics. We calibrated the model at a long drought experiment site (Caxiuanã). We then ran the model over Amazonia forests using as an input gridded climate fields and rising atmospheric CO2 from 1901 to 2019. The model reproduced the drought sensitivity of aboveground biomass (AGB) growth and mortality observed at forest plots across selected Amazon intact forests for 2005 and 2010, and the net balance between these two carbon fluxes. No plot data have been published yet for the recent 2015/16 El Nino, but we predict a more negative sensitivity of the net carbon sink during this event compared to the former 2005 and 2010 droughts. We then ranked all past drought events of the last century based on their maximum cumulated water deficit anomalies, and found that 2015/16 was the most severe drought in terms of both AGB loss and area experiencing a severe carbon loss. Because of the 2015/16 event, together with the 2005 and 2010 droughts, the last 20 years was the period with the largest climate-driven cumulative AGB loss than any other previous 20-years period since 1901. Factorial simulations allowed us to separate the individual contribution of climate change and rising CO2 concentration on AGB dynamics. We found that even if climate change did increase mortality, increased CO2 concentration contributed to balance the C loss due to mortality. This is because, in our model, CO2-induced stomatal closure reduces transpiration and increases soil moisture, offsetting increasing transpiration from CO2 induced higher foliage area.
Hydrogeological inference by adaptive sequential Monte Carlo with geostatistical resampling model proposals
Authors: Amaya Macarena , Linde Niklas , Laloy Eric
Published: March 2022

For strongly non-linear inverse problems, Markov chain Monte Carlo (MCMC) methods may fail to properly explore the posterior probability density function (PDF). Particle methods are very well suited for parallelization and offer an alternative approach whereby the posterior PDF is approximated using the states and weights of a population of evolving particles. In addition, it provides reliable estimates of the evidence (marginal likelihood) that is needed for Bayesian model selection at essentially no cost. We consider adaptive sequential Monte Carlo (ASMC), which is an extension of annealed importance sampling (AIS). In these methods, importance sampling is performed over a sequence of intermediate distributions, known as power posteriors, linking the prior to the posterior PDF. The main advantages of ASMC with respect to AIS are that it adaptively tunes the tempering between neighboring distributions and it performs resampling of particles when the variance of the particle weights becomes too large. We consider a challenging synthetic groundwater transport inverse problem with a categorical channelized 2D hydraulic conductivity field designed such that the posterior facies distribution includes two distinct modes with equal probability. The model proposals are obtained by iteratively re-simulating a fraction of the current model using conditional multi-point statistics (MPS) simulations. We focus here on the ability of ASMC to explore the posterior PDF and compare it with previously published results obtained with parallel tempering (PT), a state-of-the-art MCMC inversion approach that runs multiple interacting chains targeting different power posteriors. For a similar computational budget involving 24 particles for ASMC and 24 chains for PT, the ASMC implementation outperforms the results obtained by PT: the models fit the data better and the reference likelihood value is contained in the ASMC sampled likelihood range, while this is not the case for PT range. Moreover, we show that ASMC recovers both reference modes, while none of them is recovered by PT. However, with 24 particles there is one of the modes that has a higher weight than the other while the approximation is improved when moving to a larger number of particles. As a future development, we suggest that including fast surrogate modeling (e.g., polynomial chaos expansion) within ASMC for the MCMC steps used to evolve the particles in-between importance sampling steps would strongly reduce the computational cost while still ensuring results of similar quality as the importance sampling steps could still be performed using the regular more costly forward solver.
Hydroclimatic variability in the West Sahara and West Mediterranean during the last 150,000 years
Authors: Camuera Bidaurreta Jon , Ramos-Román María J. , Jiménez-Moreno Gonzalo , García-Alix Antonio , Seppä Heikki
Published: March 2022

 The continental and marine pollen-based quantitative reconstructions and the West Saharan dust records of the last 150,000 years are excellent paleoclimate proxies to observe variations in humidity and aridity as well as to evaluate similarities and differences in the climate history of the West Mediterranean and West African regions. The quantitative mean annual precipitation reconstruction from the western Mediterranean (southern Iberia and Alboran Sea) shows that during the Last Interglacial and the Early Holocene, the mean annual precipitation in this region was around 600-650 mm/yr, 200 mm/yr higher than the recent values (ca. 450 mm/yr). With respect to the cold Heinrich Stadials (from HS1 to HS6), the West Mediterranean and West Sahara show similar climatic trends and are characterized by strong and synchronous droughts. In particular, during these periods the West Mediterranean stack suggests mean annual precipitation values of 200-350 mm/yr. Here, we aim to elucidate the climate mechanisms affecting both regions during the most arid events of the last glacial period (i.e., Heinrich Stadials) as well as the similarities/differences between the African Humid Periods and the West Mediterranean Humid Periods for the last interglacial-glacial cycle.
Eddies in the marginal ice zone of Fram Strait and Svalbard from spaceborne SAR observations in winter
Authors: Kozlov Igor , Atadzhanova Oksana , Pryakhin Sergey
Published: March 2022

In this work we investigate the intensity of eddy generation and their properties in the marginal ice zone (MIZ) of Fram Strait and around Svalbard using spaceborne synthetic aperture radar (SAR) data from Envisat ASAR and Sentinel-1 in winter 2007 and 2018. Analysis of 2039 SAR images allowed identifying 4619 eddy signatures in the MIZ. While the overall length and the area of MIZ are different in 2007 and 2018, the number of eddies detected per image per kilometer of MIZ length is similar for both years.
Eddy diameters range from 1 to 68 km with mean values of 6 km and 12 km over shallow and deep water, respectively, suggesting that submesoscale and small mesoscale eddies prevail in the record. At eddy diameter scales of 1-15 km, cyclones strongly dominate over anticyclones. However, in the range of 15-30 km this difference is gradually vanishing, and for diameter values above 30 km anticyclones start to dominate slightly.
Mean eddy size grows with increasing ice concentration in the MIZ, yet most eddies are detected at the ice edge and where the ice concentration is below 20%. The fraction of sea ice trapped in cyclones (53%) is slightly higher than that in anticyclones (48%). The amount of sea ice trapped by a single ‘mean’ eddy is about 40 km2. Here we also attempt to give a first-order estimate of the eddy-induced horizontal sea ice retreat using observed values of eddy radii and amount of sea ice trapped in the eddies, and empirical mean values of ice bottom ablation and ice thickness. The obtained average horizontal ice retreat is about 0.2-0.5 km·d–1 ± 0.02 km·d–1. The spatial patterns of the eddy-induced horizontal sea ice retreat derived from SAR data suggest a pronounced decrease in MIZ area and a shift in the edge location that agrees with the observations.
The analysis of the spatial correlation between eddies, currents and winds shows that the intensity of eddy generation/observations and their detectability in the MIZ, and the width of eddy bands correlate with the intensity of northern and northeasterly winds. In some regions, e.g. along the Greenland Sea shelf break, in Fram Strait and over the Spitsbergen Bank the probability values of eddy occurrence in the MIZ seem to correlate with stronger boundary currents, while north of Svalbard and over Yermak Plateau higher eddy probability values are observed under low/moderate currents and winds.
This study was supported by the Russian Science Foundation grant # 21-17-00278 (analysis of sea ice conditions, ice trapping and melting by eddies) and by the Ministry of Science and Higher Education of the Russian Federation state assignment # 075-00429-21-03 (data acquisition & processing).
The effect of rainfall pattern on sediment source in a small catchment on the Chinese Loess Plateau
Authors: Liu Ying , Yang Mingyi , Zhang Fengbao , Zhang Jiaqiong
Published: March 2022

Understanding the influence of rainfall pattern on suspended sediment source on catchments and river basin scales is of great importance for reasonable implementing of soil conservation and sediment control measures. Such information, however, is unavailable or difficult to assemble. According, this study used the rainfall data from 2011 to 2013 recorded by pluviograph to analyze the effect of rainfall pattern on sediment source in the Qiaozi West catchment on the Chinese Loess Plateau. The suspended sediment in six erosive rainfall events were continuous collected at the outlet of the catchment and surface soil samples were collected from potential sediment sources  including, inter-gully (farmland, forest, grassland) and gully areas (gully slope and gully wall) of the watershed. A total of 54 rainfall events were divided into four patterns according to the variation of rainfall intensity in rainfall processes, which were advanced, intermediate, delayed, and uniform patterns. The rainfall was dominated by the advanced pattern in the studied catchment, which accounts for 43% of all observed rainfalls. There were six rainfall events had suspended sediment samples, two intermediate pattern erosive rainfall events generated the largest percentage of the total sediment yield of six events. The results based on the composite fingerprinting approach indicated that farmland and gully wall were the main sediment source in the catchment regardless of rainfall patterns. However, cultivated field having loose topsoil created in tillage has relatively high contribution to suspended sediment in runoff at the advanced pattern, while loose materials from collapsed gully walls has relatively high contribution to suspended sediment in runoff at the intermediate and delayed rainfall pattern. Further studies are necessary to gain better insight into erosion pattern variation under different rainfall pattern.
Results from the Emirates Mars Mission (EMM) - Hope Probe
Authors: Almatroushi Hessa , Deighan Justin , Edwards Christopher , Holsclaw Gregory , Wolff Michael ,   EMM Science Team
Published: March 2022

The Emirates Mars Mission (EMM) – Hope Probe – has commenced its one-Martian-year science phase on May 23rd 2021. The goals of the mission aim to understand the Martian atmosphere, its processes, dynamics, and circulation using three scientific instruments observing Mars' different atmospheric layers simultaneously. 

Hope Probe is studying the lower atmosphere of Mars using the Emirates eXploration Imager (EXI) and the Emirates Mars Infrared Spectrometer (EMIRS). While EXI measures the distribution of water ice and ozone using ultraviolet bands, EMIRS measures the optical depth of dust, ice clouds and water vapor in the atmosphere, in addition to the temperature of the surface and the atmosphere using infrared bands. On the other hand, the Emirates Mars Ultraviolet Spectrometer (EMUS) is studying the upper atmosphere of Mars through extreme and far ultraviolet bands to measure the distribution of carbon monoxide and oxygen in the thermosphere, and oxygen and hydrogen in the exosphere of Mars.

The scientific observations are taken from a unique high-altitude orbit with dimension 20,000 x 43,000 km that offers unprecedented local and seasonal time coverage over most of the planet. This presentation will highlight key atmospheric and surface results from the Hope Probe since it started collecting scientific data on the Martian atmosphere upon arrival to Mars on February 9th 2021. The data returned from the mission is enabling us to improve our understanding of the weather circulation in the lower atmosphere, the mechanisms behind the upward transport of energy and particles, and the subsequent escape of atmospheric particles from the gravity of Mars.
Detecting earthen dam defects using seismic interferometry monitoring on Distributed Acoustic Sensing data
Authors: Mordret Aurelien , Stork Anna , Johansson Sam , Lavoue Anais , Beaupretre Sophie , Courbis Romeo , David Ari , Lynch Richard
Published: March 2022

Earthen dams and embankments are prone to internal erosion, their most significant source of failure. Standard monitoring techniques often measure erosion effects when they appear at the surface, reducing the potential response time to address the problem before failure. Through their integrative sensitivity along their propagation, seismic signals are well suited to assess mechanical changes in the bulk of a dam. Moreover, seismic velocities are strongly sensitive to porosity, pore pressure, and water saturation, physical properties that vary the most for internal erosion. Here, we used fiber optics and a Distributed Acoustic Sensing (DAS) array installed on an experimental dam with built-in defects to record the ambient seismic wavefield for one month while the dam reservoir is gradually filled up. The position and nature of the dam defects are unknown to us, to allow an actual blind-detection experiment. We computed cross-correlations between equidistant channels along the dam every 15 minutes and monitored the relative seismic velocity changes at each location for the whole month. The results show a strong correlation of the velocity changes with the water level in the reservoir at all locations along the dam. We also observe systematic deviations from the average velocity change trend. We interpret these anomalies as the effects of the built-in defects placed at different positions in the bulk of the dam. The careful analysis of the residual velocity changes allows us to hypothesize on the position and nature of the defects. 
Determination of OH radical concentrations between 80-325 m over the Amazon rainforest using BVOC measurements
Authors: Ringsdorf Akima , Edtbauer Achim , Vila-Guerau de Arellano Jordi , Williams Jonathan , Lelieveld Jos
Published: March 2022

The tropical rainforest is the largest source of VOCs to the global atmosphere [1], where they are oxidized primarily by the hydroxyl radical (OH) [2]. In-situ measurements of OH are rare, especially from tropical forests, but indirect OH estimates can be made using VOC concentrations measured from aircraft or towers. For this it is necessary to measure the vertical change in concentration of a specific VOC with a known OH rate coefficient, within a known reaction time. In this study volatile organic compounds (VOC) were measured on the Amazon Tall Tower Observatory (ATTO) from 3 heights (80, 150 and 325 m) above the Amazon rainforest with a PTR-TOF-MS 4000 (IONICON Analytik GmbH). Typically to estimate OH, the convective timescale of the boundary layer is taken as the approximate reaction time. However, here we have developed a new method to determine the vertical transport based on the dynamic time warping technique. Median averaged transport times from 80 m to 325 m ranged from 105 to 15 minutes with decreasing values throughout the day from 06:00 to 15:00 as thermal and shear driven convection increases. We apply this method to determine effective OH concentrations between 80-325 m using isoprene and its oxidation products (methyl vinyl ketone, methacrolein and ISOPOOH) and compare these empirically derived values to values from the large-eddy simulation DALES [3]. The timescales of turbulent mixing and OH chemistry are similar, so both govern the vertical change in concentration.

[1] Guenther, Alex. “Biological and Chemical Diversity of Biogenic Volatile Organic Emissions into the Atmosphere.” ISRN Atmospheric Sciences 2013 (2013): 1–27. https://doi.org/10.1155/2013/786290.

[2] Lelieveld, Jos, Sergey Gromov, Andrea Pozzer, and Domenico Taraborrelli. “Global Tropospheric Hydroxyl Distribution, Budget and Reactivity.” Atmospheric Chemistry and Physics 16, no. 19 (2016): 12477–93. https://doi.org/10.5194/acp-16-12477-2016.

[3] Vilà-Guerau de Arellano, J., X. Wang, X. Pedruzo-Bagazgoitia, M. Sikma, A. Agustí-Panareda, S. Boussetta, G. Balsamo, et al. “Interactions Between the Amazonian Rainforest and Cumuli Clouds: A Large-Eddy Simulation, High-Resolution ECMWF, and Observational Intercomparison Study.” Journal of Advances in Modeling Earth Systems 12, no. 7 (2020): 1–33. https://doi.org/10.1029/2019MS001828.
Thermoelastic effects on resonance frequency of rock columns at daily scale, and modeling by acousto-elasticity 
Authors: Guillemot Antoine , Baillet Laurent , Larose Eric , Bottelin Pierre
Published: March 2022

Among slope instabilities, prone-to-fall rock columns are known to exhibit features of strong vibration modes. Corresponding resonance frequencies can be tracked by seismic instrumentation for monitoring column’s mechanical and structural properties, as well as preventing any irreversible failures. In previous studies, superficial thermoelastic effects were supposedly driving resonance frequencies daily fluctuations, but not qualitatively neither quantitively evidenced[1]. Our work corroborates this hypothesis and quantifies the physical processes involved. We interpret daily variations of resonance frequencies in Les Arches study site (Vercors, French Prealps) [2] through a thermo-mechanical model based on finite-element method. The fluctuations of modelled resonance frequencies along day match closely the observed ones, reproducing the frequency increase at daytime of around 2%. In addition, our model allows explaining the various behaviors observed across study sites: the frequency response strongly depends on solar exposition, as well as timing and intensity of both radiative and convective heat fluxes. For future instrumentation, we hence recommend the deployment of pyranometers on rocky sites in order to accurately invert acousto-elastic parameters along time, thus tracking rock fracturing through acousto-elasticity monitoring.

[1] Colombero, C., Jongmans, D., Fiolleau, S., Valentin, J., Baillet, L. & Bièvre, G. (2021) Seismic Noise Parameters as Indicators of Reversible Modifications in Slope Stability: A Review. Surv Geophys. doi:10.1007/s10712-021-09632-w

[2] Bottelin, P., Lévy, C., Baillet, L., Jongmans, D. & Guéguen, P. (2013) Modal and thermal analysis of Les Arches unstable rock column (Vercors massif, French Alps). Geophys J Int, 194, 849–858. doi:10.1093/gji/ggt046
Studies of the effect of stratospheric ozone depletion on tropospheric oxidising capacity over the period 1979-2010 using the UKCA Chemistry-Climate model
Authors: Griffiths Paul , Keeble James , Hickman Sebastian , Shin Youngsub Matthew , Abraham N Luke , Pyle John , Archibald Alexander
Published: March 2022

A grand challenge in the field of chemistry-climate modelling is to understand the connection between anthropogenic emissions, atmospheric composition and the radiative forcing of trace gases and aerosols. 

We present an analysis of the trends in tropospheric oxidising capacity in the UM-UKCA from the recent forerunner to AerChemMIP, the Chemistry-Climate Model Intercomparison project, CCMI-1, focusing on the REFC1SD and REFC1 simulations over the recent historical period.  We discuss these trends in terms of OH preconditions, such as photolysis rate and ozone concentration, and the resulting impact on methane oxidation.

Observational data provide important constraints on ozone and its precursors, as well as other radiatively important gases such as methane.  Data are available from a variety of platforms, spanning a range of spatial and temporal scales covering the past 40 years.   Recent work has highlighted the discrepancy in model and observations concerning surface ozone at key stations and the trend in tropospheric ozone levels over the past 50 years.

We will present a comparison between modelled OH and recent observational products, such as flight data from the UK ACSIS  and NASA AToM campaigns to examine how such data may be used to assess and to validate chemistry-climate models such as UKCA, and so improve the uncertainty regarding key forcing agents such as methane, ozone and aerosols. 
Large-scale drainage disequilibrium in central Australia
Authors: Ruetenik Gregory , Jansen John , Sandiford Mike , Moucha Robert
Published: March 2022

It has been hypothesized that Australia is experiencing long-wavelength uplift and subsidence in response to intraplate stresses and/or dynamic topography (e.g. Beekman et al., 1997; Czarnota et al., 2013). In central Australia, intraplate stresses are of particular interest due to the presence of several enigmatically long-lived (500+ Myr) Bouguer anomalies of magnitude + 150 mgal. Additionally, a recent study by Jansen et al. (2022) showed that the Finke river, which drains away from a large gravity high, is actively responding to cyclic changes in uplift. Here, transient uplift and subsidence of up to ~150 m may be driven by the the flexural response to variable in-plane stresses in the presence of large loads embedded within the lithosphere.  The in-plane stress changes may be associated with shear at the base of the lithosphere and therefore inherently linked to plate velocity and mantle dynamics.
     Here, we explore mechanisms of uplift in central Australia and investigate their signatures within the geomorphic record through numerical modeling and χ analysis. We observe strong χ variations across drainage divides associated with gravity anomalies, which we link to episodic transitions from exorheic to endorheic drainage during periods of uplift and subsidence.  Landscape evolution models that incorporate flexural uplift in response to time-transient variations in horizontal stresses suggest that depositional patterns, spatial χ variations, and river profiles can be explained by this uplift mechanism.  In a more general sense, these results demonstrate that the cyclic loss and gain of drainage area during periods of endorheism and exorheism can result in drastic, sudden changes in χ which correspond to waxing and waning of basinal areas.
Daily 1 km gridded temperature and precipitation in Bhutan 
Authors: Lehner Fabian , Formayer Herbert
Published: March 2022

Gridded climatological data derived for Bhutan from internationally available data sets either come at very low spatial resolution, do not provide daily data or contain few in-situ measurements. We present a newly developed daily high-resolution (1 km) gridded data set for Bhutan covering the years 1996 to 2019 for precipitation and for maximum and minimum temperature (BhutanClim) and compare it with state-of-the-art global observation data sets. As input, we used quality controlled and homogenized data from up to 67 weather stations from the National Center for Hydrology and Meteorology of Bhutan (NCHM).

The spatial interpolation method of temperature is based on methods that have already been successfully implemented in Austria, Switzerland and Germany. It allows non-linear lapse rates and considers geographical obstacles in the interpolation. The new climatology benefits from the use of local measurements and shows plausible small scale spatial patterns. Compared to other available state-of-the-art data sets BhutanClim there are new features especially in the precipitation field: Some valleys in central Bhutan border a dry climate classification according to Köppen-Geiger.
How UV light photography can be of help to palaeontologists?
Authors: Crippa Gaia , Masini Stefano
Published: March 2022

The analysis of fossil specimens under ultraviolet (UV) light represents a powerful tool in palaeontology. It has been frequently applied in this field only in the last twenty years, although it was discovered at the beginning of the 20th Century. Up to now this technique has been applied mainly on mollusc shells, but the number of studies dealing with other taxa, like vertebrate specimens, is increasing. Despite this, the analysis of fossil specimens under UV light represents a technique still not fully comprehended; the knowledge of the best procedure of sample preparation and photography still needs to be clarified and new data are required to better understand the real potential of this method. Here, we have tested different preparation (bleached vs not bleached specimens) and photographic techniques to define a protocol for UV analysis of fossil specimens and have explored its main applications analysing specimens from different stratigraphic contexts (from the Permian to the Holocene, from Oman to Italy), having different biominerals (calcite, aragonite, bioapatite and silicified and phosphatized specimens) and belonging to invertebrate and vertebrate taxa (bivalves, gastropods, brachiopods, fish, crustacean and reptile); also, we use two different wavelengths: the commonly used 365 nm, and the 440 nm, a “borderline wavelength” here adopted for the first time. Our results indicate that bleach treatment is not recommended for calcite-shelled brachiopods, whereas is suggested for aragonite-shelled molluscs. We show that UV photography enhances morphological characters and colour patterns and allows to distinguish soft-bodied fossils from the matrix, having important implications in several palaeontological fields and no limitations for its application in invertebrate or vertebrate specimens. Also, the use of UV light provides an inexpensive method to detect man-made interventions in fossil specimens and thus fake fossils. However, the nature of the biomineral and shell microstructures cause different UV responses, whereas the stratigraphic context affects specimen preservation influencing pigment preservation.
Modeling microplastic deposition in sandy streams with moving bedforms
Authors: Peleg Eshel , Johnson William P. , Teitelbaum Yoni , Arnon Shai
Published: March 2022

Microplastic (MP) delivery from the terrestrial to aquatic environments is a global concern to many ecosystems and potentially also to humans. Currently, a limited number of models can accurately predict how MPs move through streams and rivers toward the oceans. The limited predictive power of classical colloid filtration theory and the lack of models that take into account the interactive effect between streambed characteristics, flow conditions and particle characteristics limit our ability to model the deposition of MP in streambeds. This study combines improved mechanistic prediction of colloid attachment with a model that predicts flow and transport of particles in a moving streambed to quantify MP deposition in streams. A set of numerical simulations were conducted using sand with D50 of 0.3 mm and hydraulic conductivity of 0.12 cm/s. Such sand is predicted to form ripples with a length of approximately 17 cm and a height of 1.9 cm. Coefficient of attachment (Katt) was predicted for simulated MP particles of four different densities (900, 1050, 1140, and 1350 (Kg/m3), which are typical densities of Polypropylene [PP], Polystyrene [PS], Polyamide [PA], Polyethylene terephthalate [PET], respectively. In addition, model scenarios included three colloidal sizes (0.5, 1, 10 μm) and various overlying stream velocities of 0.1-0.5 m/sec. Such stream velocities were predicted to yield bed celerities between 0-130 cm/hr. Hyporheic exchange flux between the stream and the bed increased non-linearly with celerity and was found to be ten times greater for the fast celerity (130 cm/hr at stream velocity of 0.5 m/sec) as compared to slow-moving bedform with the same geometry (10 cm/hr at stream velocity of 0.2 m/sec). Difference hyporheic exchange fluxes are also expected to influence the rate of MP delivery to the bed and their deposition. Initial simulations show that increased bedform celerity and Katt lead to a shallower depth of MP deposition and a more compact distribution in the bed. Increased celerity reduces deposition depth by flattening hyporheic exchange flow paths. Therefore, despite an increased flux of MP into the bed under high stream water velocity, deposition occurs at shallower depths, and the chance for resuspension due to erosion of the bed sediment increases. Quantifying the deposition rates and residence time in the bed is essential for understanding the transfer of MP through streams and rivers toward the oceans, developing sampling strategies, and finding long-term solutions for reducing their concentrations and the associated risks.
Microbiological and agrochemical characteristics of abandoned agricultural soils of central part of Yamal region
Authors: Abakumov Evgeny , Nizamutdinov Timur , Morgun Eugenia
Published: March 2022

The microbiological and agrochemical parameters of the soils of fallow (abandoned), active agroecosystems and background (benchmark) landscapes of the Yamalo-Nenets Autonomous Region were studied. The soils of vegetable gardens (the setllements of Muzhi, Nadym, Tovopogol, Polyarny, Seyakha), the soils of parks, recreational and industrial zones and archaeological monuments (the cities of Nadym, Labytnangi, Salekhard, Novy Urengoy) were studied. The morphological and taxonomic diversity of natural and agro-soils of the key plots of the study has been established. The key chemical and soil-hydrophical differences of agrozems and agro-soils from natural background soils are revealed. The parameters of the alpha and beta diversity of the soil microbial community were studied by new generation sequencing methods. The phylums of microorganisms common to all the studied soils and those phylums that are characteristic of agrogenic soils are revealed. In some cases, there is an increase in the parameters of biodiversity in agrogenic soils in comparison with to natural ones, which indicates the diversification of edaphic ecological niches. The parameters of the metabolic dynamics of the microbial community under the conditions of chemical contamination of cryogenic soils are established. Ecotoxicological studies of soils of urbanized ecosystems of a number of settlements of the Yamalo-Nenets Autonomous Regions were carried out, even in terms of assessing ecosystem services of soils. A structure has been created and a database has been partially filled, including information on the localization, diversity, current state and use of agrogenic soils in the region.

This work was supported by Russian Foundation for Basic Research, project No 19-416-890002
Post-5 Ma rock deformation on Alonnisos (Greece) constrains the propagation of the North Anatolian Fault
Authors: Porkoláb Kristóf , Willingshofer Ernst , Sokoutis Dimitrios , Békési Eszter , Beekman Fred
Published: March 2022

The localization of the North Anatolian Fault in the northern Aegean Sea (North Aegean Trough) is an intriguing example of continental transform fault propagation. Understanding this process critically depends on quantifying the amount of strike-slip displacement and the superposition of normal and strike-slip faulting in the region, which is the aim of this study. In particular, we unravel and quantify normal and dextral faulting along the Alonnisos fault system, at the south-western margin of the North Aegean Trough (Sporades Basin), in order to constrain the spatial and temporal evolution of the basin and the North Anatolian Fault. We present detailed structural data collected from Messinian strata of Alonnisos to infer the amount of tilting and shortening and to constrain normal and dextral faulting along the Alonnisos fault system through simple analytical half-space models of dislocations. The Messinian rocks of Alonnisos record significant tilting and gentle folding close to the termination zone of the main fault segment. The tilting of the Messinian rocks implies footwall uplift in the order of 6-7 km (vertical displacement) during normal faulting on the boundary fault system, which lead to post 5 Ma substantial deepening of the Sporades Basin. The post-Messinian folding accommodated ~ 1 km shortening at the footwall termination zone of the Alonnisos fault, which implies a dextral slip of 3-4 km. Our results support the models of currently distributed dextral strain in the North Aegean in response to the propagation of the North Anatolian Fault. However, similarities with the evolution of the Sea of Marmara might suggest that dextral shear could yet become fully localized in the NAT in the next few Myrs.
TotalBrO: First results of a small solar occultation instrument for the stratosphere
Authors: Holzbeck Philip , Voss Karolin , Kleinschek Ralph , Nordmeyer Hans , Pfeilsticker Klaus , Butz André
Published: March 2022

Spectroscopic remote sensing in solar occultation geometry offers an important tool for determining atmospheric trace gas concentrations in the middle atmosphere. Monitoring ozone-depleting substances such as halogen oxides is essential to watch the ozone layer throughout a changing climate. The new TotalBrO instrument consists of an active solar tracker (LxWxH ~ 0.40 x 0.40 x 0.50 m, weight ~ 12 kg) and a spectrometer unit (LxWxH ~ 0.45 x 0.40 x 0.40 m, weight ~ 25 kg) with two temperature-stabilized grating spectrometers for the UV/visible spectral range. The instrument is compact and designed to measure bromine and iodine monoxide  (BrO and IO) in addition to other gases such as ozone (O3) and nitrogen dioxide (NO2) by means of Differential Optical Absorption Spectroscopy (DOAS). Sets of spectra collected during balloon ascent, sunset and sunrise allow for inferring vertical profiles of the gases.

Here, we report on the first deployment of TotalBrO on a stratospheric balloon launched from Kiruna, Sweden, during the Klimat campaign in August 2021. The solar tracker was able to track the sun once the balloon gondola was azimuthally stabilized above altitudes of about 25 km. TotalBrO collected UV/visible absorption spectra throughout solar occultation during sunset and sunrise on August 21/22, 2021. For the solar occultation periods, the tracking deviation with respect to the center of the solar disk was in the targeted regime of < 0.05°, and the solar tracker was able to catch the sun down to solar zenith angles (SZA) of around 95°, corresponding to tangent heights of about 10 km. We show preliminary results for profile retrievals of O3 and NO2 and for DOAS analyses of BrO and IO. The latter currently suffer from an unexplained oscillatory spectral pattern, for which we report on extensive sensitivity studies.
Dusty-Gas Simulations of Io's plumes
Authors: Klaiber Lea , Thomas Nicolas , Marschall Raphael
Published: March 2022

Io is the innermost Galilean satellite of Jupiter and is the most volcanically active body

in our solar system. Its largest volcanic plumes can rise up to several hundred kilometers

above the surface. These volcanic plumes are one known source of Io's SO2 atmosphere,

but additionally the surface of the moon is covered with surface frost which sublimates in

sunlight and condenses during the night and when Io enters eclipse behind Jupiter. There-

fore, Io's atmosphere is a result of the combination of volcanism and sublimation, but it is

unknown exactly how these processes work together to create the observed atmosphere. We

are investigating the flow of SO2 gas from the source of a plume, into the umbrella-shaped

canopy, and eventually back onto the surface. Additionally, we also study the interaction of

the plumes with an ambient sublimation atmosphere. Both, the gas flow of the plume and

the sublimation atmosphere, are modelled using the Direct Simulation Monte Carlo (DSMC)

method first utilised by G.A.Bird. The DSMC method is the most suitable for this case

because the gas dynamics can be modeled over a great range of gas densities which is es-

pecially important for rarefied gas flows at high altitudes and on the night side of Io. Our

DSMC code is multi-species and also allows the simulation of gas emission from lava lakes

that may also contribution to the atmosphere. Finally, we are also able to implement dust

particles in the plume and analyse the effect for different dust sizes. Our goal is to gain a

better understanding of the plume structure, the interaction with the ambient atmosphere

and the overall contribution of different processes to Io's atmosphere in preparation for future

missions such as JUICE, Europa Clipper and a possible future Io Volcano Observer.
Estimation of the reference hydrological conditions in Slovenia with application of clustering analysis
Authors: Šantl Sašo , Javornik Luka , Zabret Katarina
Published: March 2022

The reference hydrological conditions describe the natural discharge as it would be without the exploitation of the water resources. The measured values of the discharge are obtained in the scope of national hydrological monitoring and are in most cases reduced for the amount of abstracted water. Therefore, the values measured in this way provide information on the amount of residual water in the river and not the total amount of water that would be available without abstraction. However, knowing the natural hydrological state is important when calculating the ecological flow and planning the future water use. For this purpose, our goal was to established the methodology for estimating the reference discharge on any water body in Slovenia with catchment size larger than 10 km2. The development of the methodology was based on detailed simulations of reference hydrological conditions for 56 selected cases. As those simulations require extensive data preparation and are very time consuming, we intended to generalize the results obtained for selected cases to the whole country using clustering analysis. The hierarchical clustering and K-means approach were applied taking into account different model arguments (e.g. number of clusters, distance metrics, number of iterations). First we have grouped the simulation points to check which of the attribute data influence the classification the most. Than clustering was repeated on the data set representing points distributed over the whole country as well as simulation points. However, the further analysis of the clustering results and application of other methods for generalization showed, that clustering analysis is in this case suitable for analysis of patterns in data and identification of influential variables, while generalization turned out to be better performed applying multiple regression analysis.
Karst spring discharge modeling based on deep learning using spatially distributed input data
Authors: Wunsch Andreas , Liesch Tanja , Cinkus Guillaume , Ravbar Nataša , Chen Zhao , Mazzillli Naomi , Jourde Hervé , Goldscheider Nico
Published: March 2022

Despite many existing approaches, modeling karst water resources remains challenging and often requires solid system knowledge. Artificial Neural Network approaches offer a convenient solution by establishing a simple input-output relationship on their own. However, in this context, temporal and especially spatial data availability is often an important constraint, as usually no or few climate stations within a karst spring catchment are available. Hence spatial coverage is often unsatisfying and can introduce severe uncertainties. To overcome these problems, we use 2D-Convolutional Neural Networks (CNN) to directly process gridded meteorological data followed by a 1D-CNN to perform karst spring discharge simulation. We investigate three karst spring catchments in the Alpine and Mediterranean region with different meteorologic-hydrological characteristics and hydrodynamic system properties. We compare our 2D-models both to existing modeling studies in these regions and to own 1D-models that are conventionally based on climate station input data. Our results show that our models are excellently suited to model karst spring discharge and rival the simulation results of existing approaches in the respective areas. The 2D-models show a better fit than the 1D-models in two of three cases, learn relevant parts of the input data themselves and by performing a spatial input sensitivity analysis we can further show their usefulness to localize the position of karst catchments.
Sequential extraction based environmental risk assessment of potentially toxic elements in the topsoil of two sloping vineyards (Tokaj-Hegyalja, Hungary)
Authors: Thi Ha Pham Nhung , Babcsányi Izabella , Farsang Andrea
Published: March 2022

Soils in vineyards face various agronomic problems, such as low organic carbon content, fertility loss, and soil erosion. In particular, the intensive use of fertilizers and copper-based fungicides has resulted in the enrichment of potentially toxic elements (PTEs) in vineyard soils. These PTEs are recovered in different geochemical fractions, significantly affecting their behavior and toxicity in the soil environment. Therefore, in the present study, the geochemical distribution of Zn, Pb, Co, Ni, Cr, and Cu in the topsoil of two sloping vineyards in Tokaj-Hegyalj (NE Hungary) was investigated using the BCR sequential chemical extraction method. A risk assessment code (RAC) was also used to explore the environmental risk related to the labile fraction of the PTEs.

The two sites display contrasted soils: a slightly acidic soil derived from a magmatic rock (rhyolite) in a more than 100-year-old conventional vineyard near Tállya and a moderately alkaline soil developed on loess in a 28-year-old organic vineyard near Tokaj. Our results indicate that the target PTEs are considered immobile due to their high contents recovered in the residual fraction in both vineyards. However, Co, Cu, and Pb show the highest affinity for the reducible fraction (bound to iron and manganese oxyhydroxides). Therefore, those elements are more labile and can easily be released into the soil solution upon changes in the redox potential. Indeed, reducing conditions lead to the decomposition of the oxides or hydroxides. Conversely, the oxidizable PTE fractions are below 10%, indicating their weak binding to soil organic compounds. The soil pH, CaCO3 content, and silt content play a significant role in the geochemical fractionation of PTEs in the soil. The calculated RAC based on the percentage of PTEs in the acid-soluble soil fraction reveals that Pb and Cr have a safe risk level (RAC less than 1%), while a low risk is indicated for Zn and Ni (RAC < 10%) in both vineyards. Medium (RAC < 30%) and low risk are associated with the acid-soluble Cu in Tállya and Tokaj, respectively. The increased environmental risk due to the continuous use of copper-based fungicides and the subsequent accumulation of Cu in vineyard soils should be monitored, especially in old vineyards.
Representation of extreme El Niño events and associated atmospheric moisture flux convergence patterns in observations and CMIP6 global climate models
Authors: Sanabria Janeet , Calanca Pierluigi , Neukom Raphael , Salzmann Nadine , Carrillo Carlos
Published: March 2022

Extreme precipitation in the western tropical Andes have significant socio-economic impacts in northern Peru and Ecuador. Previous investigations have shown that high impact episodes were caused by atmospheric moisture flux convergence associated with strong El Niño events in the eastern Pacific Ocean, identifying two patterns: the one emerging during the 1982/1983 and 1997/1998 events, and the one emerging during the 2015/2016 event.

In this contribution, we discuss the ability of CMIP6 global climate models to represent these two types of extreme El Niño events, by analyzing the associated atmospheric moisture transport patterns. Based on SST observations, we identified historical extreme El Niño events using the relative Niño34 index, an index recently proposed for addressing ENSO in a warming climate. We also use ERA5 to compare with the moisture flux of CMIP6. We compared 13 CMIP6 models with the historical record (1901-2014). We found the following: (1) six of the models simulated the two extremes El Niño patterns; (2) 62% of the models identify 4.5 extreme El Niño events; and (3) only 27% of the models represent the seasonality of the moisture flux convergence overestimating the moisture flux convergence branch located to the south (4° S) of its normal position (4° N).

Our results provide a starting point to investigate the impacts of climate change and its impacts on atmospheric dynamics and associated extreme events at the regional level in tropical South America.
Properties and transitions of mesoscale convective organisation during EUREC4A using unsupervised learning
Authors: Denby Leif
Published: March 2022

The representation of shallow tradewind cumulus clouds in climate models accounts for the majority of inter-model spread in climate projections,
highlighting an urgent need to understand these clouds better. In particular, their spatial organisation appears to cause a strong impact of their radiative properties and dynamical evolution. The precise mechanisms driving different forms of convective organisation which arise both in nature and in simulations are, however, currently unknown.

Using unsupervised learning for identifying regimes of convective organisation in the tropical Atlantic, we will show results from analysing: a) what the
radiative properties of different forms of organisation are, b) what atmospheric characteristics coincide with different forms of organisation and c) what transitions occur when following air-masses along Lagrangian trajectories.  Specifically, we find: a) net radiation changes significantly between different forms of organisation, b) agreement with previous studies on the importance of boundary layer wind-speed and to some degree atmospheric stability, and c) we are able to succinctly capture what transitions occur between regimes.