bluuebunny/crossref_metadata_2025 huggingface dataset:
Impacts of large‐scale Sahara solar farms on global climate, vegetation cover and solar potential
Authors: Lu Zhengyao , Zhang qiong , Miller Paul , Long Jingchao , Zhang Qiang , Berntell Ellen , Smith Benjamin
Published: March 2022

Large-scale photovoltaic solar farms envisioned over the Sahara desert can meet the world's energy demand while increasing regional rainfall and vegetation cover. However, adverse remote effects resulting from atmospheric teleconnections could offset such regional benefits. We use state-of-the-art Earth-system model simulations to evaluate the global impacts of Sahara solar farms. Our results indicate a redistribution of precipitation causing Amazon droughts and forest degradation, and global surface temperature rise and sea-ice loss, particularly over the Arctic due to increased polarward heat transport, and northward expansion of deciduous forests in the Northern Hemisphere. We also identify reduced El Niño-Southern Oscillation and Atlantic Niño variability and enhanced tropical cyclone activity. Comparison to proxy inferences for a wetter and greener Sahara ∼6,000 years ago appears to substantiate these results. In addition, through perturbed atmospheric circulations, the global cloud cover is affected, and in turn, the solar potential in many heavily solar-powered regions. Understanding these responses within the Earth system provides insights into the site selection concerning any massive deployment of solar energy in the world's deserts.
The implementation and effectiveness of vegetative barriers to regulate fluxes of runoff and sediment in open agricultural landscapes (Flanders, Belgium)
Authors: Stokes Alexia , De Boever Maarten , Bodyn Jonas , Buysens Saskia , Rosseel Liesbet , Deprez Sarah , Bielders Charles , Degré Aurore , Frankl Amaury
Published: March 2022

Abstract:

Vegetative barriers are narrow strips of plants or plant residues that are increasingly being used as measures to reduce the connectivity of catchments in terms of water and sediment fluxes (Frankl et al., 2021a). They can mostly be found at plot edges where they do not hinder farming activities too much. Their principal function is to reduce sediment export from cropland and thus mitigate negative off-site effects of erosion (e.g. muddy floods, pollution of rivers). Being implemented in concentrated flow zones where ephemeral gullying is recurrent, they also prevent their development (Frankl et al., 2018). Although vegetative barriers are increasingly being implemented in open agricultural areas, little information is available on the effectiveness of vegetation barriers at buffering the flows of water and sediment. Here, we focus on vegetative barriers that are widely implemented in Flanders (Belgium) and which are made of straw bales, wood chips or bales of coconut fibre. Based on three simulated runoff experiments performed in the field, we calculated the hydraulic roughness and sediment deposition ratio. Our experiments show that the barriers made of coconut-fibre bales performed markedly better than those of straw bales or wood chips (Frankl et al., 2021b). However, as vegetative barriers have to be renewed every few years because of the decomposition of organic material, barriers made of locally available materials are more sustainable as a nature-based solution to erosion. We conclude that the vegetative barriers are an effective way of mitigating the negative effects of soil erosion. While barriers made of coconut-fibre bales are superior in their regulation of flows of runoff and sediment, barriers made of locally sourced materials are more sustainable.

 

Keywords: agriculture, erosion control, hydrological connectivity, runoff, sediment

 

References:

Frankl, et al. (2021a) Gully prevention and control: Techniques, failures and effectiveness. Earth Surf. Process. Landforms: 46: 220– 238. https://doi.org/10.1002/esp.5033.

Frankl, A., et al. (2021b). Report on the effectiveness of vegetative barriers to regulate simulated fluxes of runoff and sediment in open agricultural landscapes (Flanders, Belgium). Land Degrad. Dev. 32: 4445– 4449. https://doi.org/10.1002/ldr.4048

Frankl, A. et al. (2018). The success of recent land management efforts to reduce soil erosion in northern France. Geomorphology 303: 84–93. doi:10.1016/j.geomorph.2017.11.018

 
Can Ganymede’s magnetopause interactions help us probe its subsurface ocean?
Authors: Kaweeyanun Nawapat , Masters Adam
Published: March 2022

The permanent magnetic field of Jupiter’s moon Ganymede is thought to arise from an Earth-like dynamo in the moon’s outer core, alongside a secondary time varying magnetic field induced by convection in the moon’s subsurface ocean. Magnetic fields of Jupiter and Ganymede meet along a current boundary known as the upstream magnetopause, whose location depends on delicate pressure balance and presence of plasma-magnetic interactions including magnetic reconnection. As Ganymede traverses the Jovian plasma sheet, magnetopause conditions vary at half-Jovian synodic period (~5.4 hr), leading to equal-period oscillations of Chapman-Ferraro (C-F) currents and subsequently Ganymede’s magnetospheric field. In this work, we (1) demonstrate that magnetic perturbations from C-F currents will cause induction in Ganymede’s subsurface ocean, and (2) constrain the extent of inducing perturbations based on the (yet unknown) range of Ganymede’s magnetopause motions. Our analysis indicates maximum ocean inductive responses of magnitude order ~1-10 nT. Although improved magnetopause tracking is required to further constrain the response value, the magnitude order lies comfortably within resolution range of the magnetometer aboard the JUpiter ICy moon Explorer (JUICE). Hence, magnetopause interactions may become a viable tool for future induction-based study of Ganymede’s subsurface ocean.
Integrated modelling for assessment the influence of aerosol feedbacks on a regional scale as a result of accidental wildfires and land cover changes in Ukraine
Authors: Savenets Mykhailo , Pysarenko Larysa , Krakovska Svitlana , Mahura Alexander
Published: March 2022

The study presents the analysis of regional atmospheric condition changes in Ukraine caused by direct and indirect aerosol effects performed by a series of simulations using the Environment – High Resolution Limited Area Model (Enviro-HIRLAM). The research is based on two case studies. The first case study includes a severe wildfire event in the Chornobyl Exclusion Zone (northern part of Ukraine) which was observed in April 2020. The second case study analyzed the influence of hypothetical total deforestation in Ukraine during the extreme heat wave and heavy rain episodes in August 2010. Enviro-HIRLAM model was run for the domain with 15-km resolution and further downscaling to 5 and 2-km resolution. The simulations include 4 running modes: reference run with no aerosol effects (CTRL); including direct (DAE), indirect (IDAE) and both (DAE+IDAE) aerosol effects. The study analyzes the aerosol impact on thermal and moisture regimes at the surface and on the model levels up to 5 km above the ground. It is emphasized the role of anthropogenic and natural processes at the surface (like wildfires, land cover changes, etc.) on the enhancing of aerosol effects during extreme and unfavorable weather conditions. This study is supported by the grants of HPC-Europa3 Transnational Access Programme for projects HPC17TRLGW IMA-WFires “Integrated Modelling for Assessment of Potential Pollution Regional Atmospheric Transport as Result of Accidental Wildfires” and HPC17ENAVF MALAWE “Integrated Modelling and Analysis of Influence of Land Cover Changes on Regional Weather Conditions/ Patterns”. The CSC - IT Center for Science Computing (Finland) is acknowledged for computational resources.
Characteristics and results of two years of a VLBI southern hemisphere intensive observing program
Authors: Böhm Sigrid , Gruber Jakob , Kern Lisa , McCallum Jamie , McCallum Lucia , McCarthy Tiege , Quick Jonathan , Schartner Matthias
Published: March 2022

The parameter dUT1 (UT1-UTC, difference of universal time to atomic time) is essential for the transformation between celestial and terrestrial reference systems, inherent in precise navigation and positioning applications. Geodetic Very Long Baseline Interferometry (VLBI) is the only technique to directly observe dUT1. Real-time or near-real-time navigation tasks are dependent on rapid access to Earth orientation estimates or predictions. On a rapid turnaround basis, dUT1 is provided via so-called intensive sessions, which are routinely observed daily for one hour on one or sometimes more baselines. All currently operational intensive sessions are observed using northern hemisphere stations only.

In a joint initiative of TU Wien, the University of Tasmania, the Hartebeesthoek Radio Astronomy Observatory, and later on also ETH Zurich, we set up the southern hemisphere intensive observing program (SI). The SI sessions are observed with three VLBI telescopes all located south of the equator: HART15M (South Africa), HOBART12 (Tasmania), and YARRA12M (Western Australia). Observations including HOBART12 are observed in mixed-mode configuration, using the VGOS receiver in Hobart and the legacy systems at the two other stations.

By January 2022, we have successfully observed, correlated, and analyzed more than 50 SI sessions from the years 2020 and 2021. The resulting dUT1 values from the southern intensives are compared with dUT1 from the EOP 14 C04 series and with the results of other "northern intensives". The residuals with respect to C04 of the SI are on the same level as those of the INT1 and INT3 sessions and also match the level of agreement between all the various southern and northern intensives series.
Carbon sequestration to different green urban land-use types in Helsinki Finland
Authors: Thölix Laura , Backman Leif , Havu Minttu , de Munck Cécile , Masson Valéry , Järvi Leena , Nevalainen Olli , Karvinen Esko , Kulmala Liisa
Published: March 2022

Solutions to reduce carbon dioxide (CO2) emissions and to achieve carbon neutrality have become an important subject. Thus, there is a growing interest in accelerating also the carbon sinks of urban vegetation and finding the best practices for designing green areas that maximize their carbon sinks and stocks. In cities, heavy management alters the natural carbon flows compared with the non-urban environment as green areas are usually irrigated and mowed, trees may have limited space to grow, and the aboveground litter is removed. Also, urban temperatures are increased due to heat island effect. Therefore, it is important to quantify urban carbon sequestration and develop models to describe urban carbon cycling. The aim of this study was to test the applicability of the different C cycling models to describe urban ecosystems and to determine the rate of carbon sequestration at different urban vegetation types.

Model performances were tested at different green spaces in Helsinki, Finland. Measurements of leaf area index, sap flow, soil respiration, soil temperature, soil moisture and photosynthesis were collected in the footprint area of the SMEAR III ICOS station in a small urban birch forest (Betula pubencens), in botanical garden with Tilia trees (Tilia cordata), in a partly irrigated lawn and in a non-irrigated lawn during 2020-2021. In addition, ecosystem-level net CO2exchange over the whole area was measured at the SMEAR III. The models tested were LPJ-GUESS, JSBACH, SUEWS and SURFEX-ISBA.
Analysis of the production of residual vegetable oils from the food and culinary industry in the city of Cuenca (Ecuador) using GIS tools
Authors: Ponce Ochoa Katerine Elizabeth , Rodrigo-Clavero María Elena , Rodrigo-Ilarri Javier
Published: March 2022

Current population growth has generated an increase in the food and culinary industry production, which has resulted in an increase in the consumption of vegetable oils on large restaurant chains as well as on small food stalls. This situation justifies the increasing generation of large amounts of residual vegetable oils that lead to serious problems in their purification due to their slow degradation.

This research is focused in the city of Cuenca (Ecuador) where a program for the collection of residual vegetable oils run by the company ETAPA – EP is being developed. It must be taken into account that this program has been implemented for a selected number of large restaurants but does not include other waste production sources, such as small restaurants, food carts and fast-food stalls that are usually quite frequent in the city and do not integrate an adequate management control over this type of residual waste.

This work explores for the first time the possibility of turning residual vegetable oils management into a source of income and job positions while protecting the environment. In order to carry out this study, information about the location of waste generation points and the amount of residual oil has been collected and processed using GIS tools.
 Channel evolution triggered by a large flash flood based on sUAV at an earthquake-affected catchment
Authors: Jin Wen
Published: March 2022

Earthquakes–induced landslides generally provide abundant loose materials at hillslopes, possiblly triggering morphological reshaping processes at river channel and riverbed during the large flash flood hydrograph and bringing huge risk to downstream. Therefore, in a Wenchuan earthquake-affected catchment, the collected hydro-meteorological data and high-precision small Unmanned Aerial Vehicle (sUAV) data were used to quantificationally analyze channel evolution by a large flash flood event on 25th and 26th June, 2018. It was found that the stable riverbed structure formed by the coarsening layer appeared in the tenth year after the Wenchuan earthquake. In confined channel, the layer can protect the channel and resist the drastic change after the flash flood event with only small bed elevtion from 0.2 m to 2 m. Without the protection of the coarsening layer, the change could reach 6 m in unconfined channnel. Meanwhile, more materials with deposition volume of 753,108 m3 from tributaries were generally taken to main channel,and more intense erosion with the volume of 1.0107 m3 mostly occurred in the downstream of tributaries. It was noted that, in the cross-section, the increased channel width could lead to the significant change with the large volume of 35 m3. Additionally, conceptual model of the generalized channel response to large flash floods was provided during multi-stage periods after the Wenchuan earthquake. It determined the rebalance processes of channel evolution in the tenth year after the earthquake. This study will contribute to understanding the post-earthquake long-term channel evolutions and could provide decision-makers of assessing the mitigation strategies for higher-magnitude flood disasters triggered by channel change in earthquake-affected watershed.
Exploring the performance of phase association algorithms
Authors: Puente Huerta Jorge Antonio , Sippl Christian
Published: March 2022

Seismic phase association plays an important role in earthquake detection and location workflows as it links together seismic phases detected on different seismometers into individual earthquakes. Together with improved phase picking algorithms, a phase association algorithm can generate large earthquake phase data sets and earthquake catalogs when applied to dense permanent or temporary seismic networks. Recently, many efforts have been made on improving seismic phase association performance, such as developing machine learning approaches that are trained on millions of synthetic sequences of P and S arrival times, to generate more precise and complete catalogs including more small earthquakes.

As part of project MILESTONE, which aims at the automatic creation of large microseismicity catalogs in subduction settings, the present study evaluates the performance of the deep-learning based phase association algorithm PhaseLink (Ross et al. 2019) by comparison with a traditional grid-based method and a small handpicked benchmark dataset.

We used seismic data from the IPOC (Integrated Plate boundary Observatory Chile) permanent deployment of broadband stations in Northern Chile, dedicated to the study of earthquakes and deformation at the continental margin of Chile.

For an initial calibration, we manually picked P and S phases of raw waveforms on 15 stations on two randomly chosen days. All events that were visually recognizable were picked and located, which led to a dataset of 251 events comprising 1823 P and 1468 S picks, spanning a depth range from the surface down to 240 km. We use this handpicked dataset as ‘ground truth’, and evaluate the performance of PhaseLink and the grid-based method coupled with a STA/LTA trigger against this benchmark, considering both the numbers of (correctly/falsely) associated events and the number of constituent picks per event.

In a second experiment, we compare PhaseLink and conventional phase associator using a much larger set of STA/LTA alerts from the same region, but without the additional ground truth.

The presented research represents first steps towards an integrated automated workflow for detecting, picking, associating and locating microseismicity in subduction zone settings.
Can cloud properties provide information on surface wind variations using deep learning?
Authors: Jamaer Sebastiaan , Neirynck Jérôme , van Lipzig Nicole
Published: March 2022

Recent studies have shown that the increasing sizes of offshore wind farms can cause a reduced energy production through mesoscale interactions with the atmosphere. Therefore, accurate nowcasting of the energy yields of large offshore wind farms depend on accurate predictions of the large synoptic weather systems as well as accurate predictions of the smaller mesoscale weather systems. In general, global or regional forecasting models are very well suited to predict synoptic-scale weather systems. However, satellite or radar data can support the nowcasting of shorter, smaller-scale systems. 

In this work, a first step towards nowcasting of the mesoscale wind using satellite images has been taken, namely the coupling of the mesoscale wind component to cloud properties that are available from satellite images using a deep learning framework. To achieve this, a high-resolution regional atmospheric model (COSMO-CLM) was used to generate one year of high resolution cloud en hub-height wind data. From this wind data the mesoscale component was filtered out and used as target images for the deep learning model. The input images of the model were several cloud-related fields from the atmospheric model. The model itself was a Deep Convolutional Neural Network (a U-Net) which was trained to minimize the mean squared error. 

This analysis indicates that cloud information can be used to extract information about the mesoscale weather systems and could be used for nowcasting by using the trained U-Net as a basis for a temporal deep learning model. However, future validation with real-world data is still needed to determine the added value of such an approach.
A predictive model of spatial soil ECa variability in the vineyard to support the monitoring of plant status
Authors: Cutaneo Carmine , Monaco Eugenia , Buonanno Maurizio , Castaldo Raffaele , Tizzani Pietro , Ezzy Haitham , Erbaggio Arturo , De Micco Veronica , Bonfante Antonello
Published: March 2022

In a vineyard, plant water status variability is strongly dependent on soil spatial variability, whose physical characteristics drive the processes involved in the soil water balance. The more the soil and its characteristics vary in space (horizontally and vertically), the less homogeneous the productive and qualitative response within the vineyard will be. In this context, the proximal sensing of apparent soil Electrical Conductivity (ECa) and its monitoring during the growing season can help understanding the nature of spatial variability of vineyard, supporting both viticultural microzoning (identifying Homogeneous and functional Homogeneous Zones, HZs and fHZs) and field experiments. In this contribution, the importance of use of ECa spatial monitoring during the grapevine growing season will be showed, highlighting its importance in the evaluation of the vineyard response and identification of FHZs.

In this direction, a predictive model of soil ECa is proposed. It consists of the spatial prediction of ECa starting from punctual measurements obtained by a network of TDR probes able to measure ECA. In order to realise this model, a machine learning method based on Random Forests was used. It was trained to derive the spatial relationships between the apparent value of ECa measured with geophysical instrument and the ECa measured with the ACCLIMA TDR probes. In this way, a spatial prediction of the ECa values of the surveyed area is possible.

The study was realized in a vineyard of southern Italy on Greco (white) grapevine, where detailed and precise records on soil and atmosphere systems, in-vivo plant monitoring of eco-physiological parameters have been conducted in 2020 and 2021, and spatial variability of plant status in vineyard monitored by means of UAV multispectral images. Apparent soil ECa was measured five timesduring the growing season 2021 by using the PROFILER EMP 400 electromagnetometer both in vertical and horizontal dipole mode. This instrument allows to simultaneously work with three frequencies (5000, 10000 and 15000 Hz) and explore different depth volumes of sub-soil. The predictive model results were processed in MATLAB and Python software and validated on plant responses obtained from vegetational indexes calculated from UAV multispectral images. The obtained results have shown how the ECa can be estimated by the predictive model carrying out important information to support vineyard monitoring.
Assessment and inventory of hazardous mountain lakes in Kyrgyz Republic
Authors: Erokhin Sergey , Zaginaev Vitalii , Allen Simon , Meleshko Anna
Published: March 2022

More than 90 % of territory of Kyrgyz Republic are mountains.  More than two thousand lakes have formed but only some lakes pose a threat to lives, assets and livelihoods. Many of these lakes are seasonally dynamic, and form in ice-rich permafrost environments that are characteristic of the region. The objective of this study was to describe and implement an evidence-based expert lake hazard assessment criteria, to produce an updated inventory of hazardous lakes, which are susceptible to outburst within the territory of Kyrgyz Republic. A total of 368 lakes susceptible to outburst in Kyrgyzstan were inventoried and classified into 5 classes: ice-dammed, ice-cored moraine-dammed, ice-free moraine dammed, bedrock-dammed and moraine- dammed, and landslide-dammed lakes. The hazardous lake inventory was most recently updated in 2021 based on field works and remote sensing analysis.

All 368 lakes were described by a number of quantitative and qualitative characteristics and were assigned different levels of outburst susceptibility. All studied lakes are situated within the elevational zone between 1200 m.a.s.l. and 4300 m.a.s.l. All lakes were estimated in terms of their surface area from remote sensing data for different years, which ranges from thousands to millions of square meters. For 47 ice cored moraine dammed lakes bathymetry measurements were conducted, for many of them several times.

The outburst susceptibility was estimated according to 4 hazard categories and each lake is assigned within a certain category depending on current lake characteristics. A particular feature of the non-stationary lakes found in this region is the rapid changes in outburst susceptibility that can occur over short time-periods. A total of 111 lakes, which at least once have been assigned with the highest hazard levels (the 1st or 2nd category) in the period from 2006-2017 were analyzed for their changes over time. According to the analysis, the hazard level of many lakes varies over time and the number of category 1 and 2 lakes has considerably decreased in the recent decade. Lakes of the 1st and 2nd hazard categories decreased since 2006 by 57 % and 45 % respectively (from 21 to 9 and 49 to 27), while the number of lakes of the 3rd and 4th categories increased from 35 to 58 and 1 to 16.

The lake hazard assessment scheme developed for the Kyrgyz Republic may be a valuable tool for scientists and authorities dealing with outburst flood hazards in other similar environments of Central Asia and elsewhere.
Fungi Contribute Substantially to Nitrous Oxide Production from Highly Acidic Soil
Authors: Yin Junhui , Liu Rui , Chen Qing
Published: March 2022

Previous studies have demonstrated the fungal contribution to N2O emission from acidic soils. Yet, mitigating the steady increase in N2O concentrations is strongly hindered by lack of knowledge on microbial mechanisms underpinning the N2O producing processes in acidic soils. The objective of the present research was to explore the microbial production mechanism of N2O emissions in acidic soils using an integrate approach combing isotopic signatures and functional gene under microcosm incubations. Five acidic soils were examined in the current study, including natural forest (NF, soil pH 5.15), tea plantation (TP, soil pH 4.04), and vegetable fields (VF1 soil pH 7.95, VF2 soil pH 5.42, VF3 soil pH 3.51). Each soil was treated with both 50 mg N kg-1 NH4SO4 and 50 mg N kg-1 KNO3. N2O emissions, soil properties and critical nitrogen-cycling biomarkers (including 16S, ITS, AOA-amoA, AOB-amoA, nirK, nosZI and nosZII) were investigated. The results show that the cumulative N2O emissions after 182 h incubation were 0.10, 11.8, 1.09, 12.2, and 96.9 nmol g-1 in NF, TP, VF1, VF2, and VF3 soils, respectively. The abundance of ITS in TP and VF3 soil was significantly higher than 16S. Pearson's correlation analysis showed that the cumulative N2O emissions had a negative relationship with soil pH, 16S/ITS ratio, and abundance of 16S, AOA-amoA and nosZI genes. The N2O isotopomer ratios (δ15Nbulk and SP) of TP and VF3 fell within the combined areas of nitrification and fungal denitrification. These finding highlighted that fungi could potentially contribute to soil N2O production via fungal denitrification in highly acidic soils and their contribution might be pronounced both in tea plantation and vegetable field.
Disentangling climate-dependent stalagmite proxies using radiocarbon timeseries
Authors: Therre Steffen , Fohlmeister Jens , Warken Sophie F. , Schröder-Ritzrau Andrea , Friedrich Ronny , Frank Norbert
Published: March 2022

The transport and incorporation mechanisms of radiocarbon (14C), stable carbon isotopes (δ13C) and trace metal ratios into speleothems have been investigated intensively in the past. This provides a crucial understanding for the detection of climate and ecosystem signals (precipitation, vegetation variability) or even changes in atmospheric composition like radionuclide concentration. The Dead Carbon Fraction (DCF) in tropical settings often revealed a positive correlation with hydrological proxies, highlighting its relation with the amount of soil water infiltration. In contrast, more arid regions can have dominant aged stocks of soil organic matter (SOM) diluting the 14C concentration of the soil CO2, which is responsible for an enhanced decoupling between speleothem DCF and hydrological proxies.

Here, we present a compilation of several new and published stalagmite 14C records in context with the predominant climatic parameters controlling their carbon signature. The records cover humid, tropical climates in Puerto Rico, temperate settings in Northern Turkey, as well as semi-arid alpine caves, and arid locations on the Arabian Peninsula. The range of mean DCF values is extreme, from below 10 to more than 60 % with δ13C values between -10 and 0 ‰. Climate-controlled mechanisms like the sensitivity of vegetation to net-infiltration changes are revealed, especially for more arid regions where aged SOM significantly contributes to stalagmite geochemistry.

In a first application, we revisit a published multi-proxy glacial record of a stalagmite from Socotra Island, which allows us to disentangle the increasing soil infiltration towards Termination I and the resulting long-term DCF trends. This is achieved by exploiting the correlation of a humidity proxy (Mg/Ca) with DCF and implementing a transfer function to correct for soil carbon effects in 14C.

Our approach hints at vast opportunities to better understand the control mechanisms in stalagmite carbon signature and correct for climate-induced effects. Therefore, it can aid future research in the search for stalagmite records which trace, for instance, atmospheric nuclide signals or bear unresolved climate-related trends.
Addressing the difficulties in quantifying the Twomey effect for marine warm clouds from multi-sensor satellite observations and reanalysis
Authors: Jia Hailing , Quaas Johannes , Gryspeerdt Edward , Böhm Christoph , Sourdeval Odran
Published: March 2022

Aerosol–cloud interaction is the most uncertain component of the overall anthropogenic forcing of the climate, in which the Twomey effect plays a fundamental role. Satellite-based estimates of the Twomey effect are especially challenging, mainly due to the difficulty in disentangling aerosol effects on cloud droplet number concentration (Nd) from possible confounders. By combining multiple satellite observations and reanalysis, this study investigates the impacts of a) updraft, b) precipitation, c) retrieval errors, as well as (d) vertical co-location between aerosol and cloud, on the assessment of Nd-toaerosol sensitivity (S) in the context of marine warm (liquid) clouds. Our analysis suggests that S increases remarkably with both cloud base height and cloud geometric thickness (proxies for vertical velocity at cloud base), consistent with stronger aerosol-cloud interactions at larger updraft velocity. In turn, introducing the confounding effect of aerosol–precipitation interaction can artificially amplify S by an estimated 21 %, highlighting the necessity of removing precipitating clouds from analyses on the Twomey effect. It is noted that the retrieval biases in aerosol and cloud appear to underestimate S, in which cloud fraction acts as a key modulator, making it practically difficult to balance the accuracies of aerosol–cloud retrievals at aggregate scales (e.g., 1° × 1° grid). Moreover, we show that using column-integrated sulfate mass concentration (SO4C) to approximate sulfate concentration at cloud base (SO4B) can result in a degradation of correlation with Nd, along with a nearly twofold enhancement of S, mostly attributed to the inability of SO4C to capture the full spatio-temporal variability of SO4B. These findings point to several potential ways forward to account for the major influential factors practically by means of satellite observations and reanalysis, aiming at an optimal observational estimate of global radiative forcing due to the Twomey effect.
The effects of rheological parameters on ice-shelf flow on centennial time scales.
Authors: Sergienko Olga
Published: March 2022

On timescales longer than several months, ice flow is treated as a non-Newtonian fluid, which viscosity depends on the second invariant of the strain-rate tensor and the temperature-dependent ice-stiffness parameter. This power-law dependence is known as Glen's flow law. Although results of laboratory experiments and inferences from in situ observations suggest a range of the power-law exponent n  from 1 to 5, the value of 3 is widely used. In studies focused on ice-shelf dynamics, the traditional approach is to use remote-sensing observations to infer the ice-stiffness parameter by means of inverse methods assuming a constant value of n=3. Focusing on the floating tongue of Pine Island Glacier, the inversions of the ice-stiffness parameter are performed for various constant as well as spatially variable values of n using present-day observations. Using the inferred parameters and basal melting derived from remote-sensing observations, the Pine Island Glacier Ice Shelf flow is simulated for hundred years. Results of simulations indicate that the effects of rheological parameters are of the order of 5%. The difference between results of hundred years simulations with observationally derived  and spatially uniform basal melting are of the order of 40%. These results indicate that on centennial timescales the ice-shelf flow is more sensitive to details of basal melting than to rheological parameters, provided the latter are constrained by observations.
Integrated petrological monitoring and eruptive parameters of volcanic products: high resolution analyses of the 11th May 2019 explosive events at Stromboli volcano (Italy)
Authors: Pontesilli Alessio , Del Bello Elisabetta , Scarlato Piergiorgio , Mollo Silvio , Ellis Ben , Andronico Daniele , Taddeucci Jacopo
Published: March 2022

Typically, petrological monitoring studies focus on comparing eruptive phenomena with textural and compositional features of eruptive products recovered over long term (days to years) sampling campaigns aiming at identifying major changes in the magmatic plumbing system and eruptive dynamics. However, as far as we are aware, there have been few attempts to combine whole rock, microchemical, and microtextural data with ground-based imaging of volcanic eruptions at high spatial (individual eruptive centers) and high temporal (minutes to hours) resolutions.

Here, we present a high-resolution petrological investigation using as test site Stromboli volcano, one of the most active and intensely monitored open-conduit volcanoes in the world and an important benchmark in understanding the physico-chemical processes related to magma and conduit dynamics. Normal eruptive activity is dominated by frequent and intermittent low-energy explosions (6 events/hour on average), throwing jets of crystal-rich basaltic scoriae, gas and ash to heights <150 m above the summit vents. On May 11th 2019, we recorded 5 hours of explosive activity and sampled individual fresh fallout ash products from eighteen explosions. Six products were erupted from the N1 vent, whereas twelve products were erupted from the S2 vent. Analysis of high speed (50 Hz) infrared videos revealed that explosive activity was more frequent at the S2 vent (8-10 events/hour) than at the N1 vent (3-5 events/hour). The explosion types were differently distributed at the two areas, with prevalent ejection of coarser material at the N1 vent and ash-dominated explosions being more frequent at the S2 vent. Thermometric and hygrometric calculations based on clinopyroxene-plagioclase-melt equilibria comparatively highlight that N1 eruptions were fed by a colder, more degassed, and differentiated magma relative to that feeding S2 eruptions. Diffusion modeling of Li concentration profiles in plagioclase also indicate longer timescales of magma degassing and ascent for N1 eruptions, possibly due to enhanced groundmass crystallization at conduit walls. 

The final emerging picture is that concurrent normal eruptions from distinct vent areas at Stromboli are heralds of distinct magma differentiation conditions within the uppermost part of the magma storage region, in close agreement with observed eruptive phenomena. This high-resolution approach has the potential to unequivocally constrain the processes driving transient, rapid, explosive eruptions in active volcanoes, thus offering new insights on the interplay between magma dynamics, ascent timescales, and eruptive behavior.
Controls on oxygen depletion under lake ice 
Authors: Perga Marie-Elodie , Minaudo Camille , Ulloa Hugo , Doda Tomy , Perolo Pascal , Escoffier Nicolas , Arthaud Florent , Obrador Biel , Bouffard Damien
Published: March 2022

Even low productive, high-altitude lakes experience deep water hypoxia under ice-cover. While the changing ice phenology is expected to ripple on the magnitude of under-ice hypoxia, the lack of a mechanistic framework linking the physical impact of ice loss to biogeochemical properties has led to seemingly contradictory conclusions.  

Biogeochemical and physical processes constrain the Dissolved Oxygen (DO) dynamic at the sediment-water interface under lake ice. On the one hand, the biogeochemical hypothesis envisions a primary control of DO decay under the ice by sediment oxygen uptake, which arises from benthic microbial respiration and the release of reduced compounds. On the other hand, the physical hypothesis assumes a greater DO decay when sediment heat release reinforces the inverse stratification; the stronger is the sediment heat release, the more the bottom layer, from which oxygen is consumed, gets isolated from potential diffusive resupply from the upper layers. The outcome of a shorter ice-cover on the under-ice DO dynamics depends on the dominance of either biogeochemical or physical processes.

Based on in-situ observations of DO and temperature, we assessed the relative share of biogeochemical and physical processes on decay under the ice of 14 high-altitude lakes in the French Alps. We found highly variable DO decay rates across the different lakes and years, with exponential coefficients ranging from 1.10-3 to 6.10-2 d-1.  The under-ice DO decay rates increased, within years and lakes, with sediment heat release, while biogeochemical factors played only a marginal role. We tested through a reaction-diffusion model on an archetypal, testbed lake the individual effects of biogeochemical versus physical processes on DO decay. We confirmed that the sediment heat flux at ice-on is a major driver of DO decay under the ice, explaining one mechanism by which shallower or more transparent lakes experience greater DO decay under the ice.
Drought Identification in NLDAS Data using Machine Learning Methods
Authors: Vassallo Corinne , Bettadpur Srinivas , Wilson Clark
Published: March 2022

Though machine learning (ML) methods have been around for decades, they have only more recently been adopted in the geosciences. The availability of existing long data records combined with the capability of ML algorithms to learn highly non-linear relationships between data sources means there is even more potential for the replacement or augmentation of existing scientific analyses with ML methods. Here, I give an example of how I used a convolutional neural network (CNN) for the task of pixelwise classification of the North American Land Data Assimilation System (NLDAS) Total Water Storage data into their corresponding drought levels based on the Palmer Drought Severity Index (PDSI). Promising results indicate there is much to be explored in the application of ML to drought identification and monitoring.
Accounting for microbial dynamics to simulate soil functions under agricultural management
Authors: König Sara , Reitz Thomas , Weller Ulrich , Vogel Hans-Jörg
Published: March 2022

Mechanistic simulation models are an essential tool for predicting soil functions such as nutrient cycling, water filtering and storage, productivity and carbon storage as well as the complex interactions between these functions. Most soil functions are driven or affected by soil organisms. Yet, biological processes are often neglected in soil function models or implicitly described by rate parameters. This can be explained by the high complexity of the soil ecosystem with its dynamic and heterogeneous environment, and by the range of temporal and spatial scales these processes are taking place at.

Here, we meet these challenges and present our approach for integrating biological microscale processes into soil modelling. We introduce our systemic soil model BODIUM which simulates relevant microbial processes at the profile scale to analyse the impact of different agricultural management and climatic conditions on soil functions. For this, BODIUM includes different microbial pools as well as C:N stoichiometric considerations but does not explicitly account for microbial community structure or composition dynamics. In our approach, soil structure dynamics at the pore scale is a critical factor for controlling the availability of carbon and nutrients as well as the distribution of water and oxygen, which in turn jointly drive microbial growth and activity. To explore the potential advantage of BODIUM, we compare our model approach with traditional modelling approaches without explicit microbial activity under different simulation scenarios. We further analyse the impact of changing microclimatic conditions of water, oxygen and nutrient availability as dedicated by a dynamic soil structure on microbial activity and the corresponding soil functions.

Finally, we discuss ongoing developments to additionally consider, e.g., microbe-fauna-interactions, microbial feedback on soil structure dynamics, and phosphor dynamics.
Development of an arctic-boreal fire atlas using Visible Infrared Imaging Radiometer Suite active fire data
Authors: Scholten Rebecca , Chen Yang , Randerson James , Veraverbeke Sander
Published: March 2022

Intensifying wildfires in high-latitude forest and tundra ecosystems are a major source of greenhouse gas emissions, releasing carbon through direct combustion and long-term degradation of permafrost soils and peatlands. Several remotely sensed burned area and active fire products have been developed, yet these do not provide information about the ignitions, growth and size of individual fires. Such object-based fire data is urgently needed to disentangle different anthropogenic and bioclimatic drivers of fire ignition and spread. This knowledge is required to better understand contemporary arctic-boreal fire regimes and to constrain models that predict changes in future arctic-boreal fire regimes. 
Here, we developed an object-based fire tracking system to map the evolution of arctic-boreal fires at a sub-daily scale. Our approach harnesses the improved spatial resolution of 375m Visible Infrared Imaging Radiometer Suite (VIIRS) active fire detections. The arctic-boreal fire atlas includes ignitions and daily perimeters of individual fires between 2012 and 2021, and may be complemented in the future with information on waterbodies, unburned islands, fuel types and fire severity within fire perimeters. 
Fast digital rock upscaling: from Stokes equation to Darcy equation
Authors: Liao Qinzhuo , Li Gensheng , Huang Zhongwei , Sheng Mao , Li Jun , Zhang Dongxiao
Published: March 2022

Permeability is a key parameter for characterizing fluid flow in digital rocks. It depends on pore geometry and topology and can be computed numerically via solving the Stokes equation. However, the associated computational effort can be enormous for large-scale models, even using the efficient Lattice-Boltzmann method. In this study, an efficient method is developed for computing the equivalent permeability of digital rocks by simplifying the Stokes equation to Darcy equation. The method is based on the idea that a 3D digital core can be approximated by the combination of multiple 2D slices/layers, and the property of each layer is governed by the Stokes equation. Specifically, to mimic the 2D fine-scale velocity solved from the Stokes equation, a local permeability is assigned according to the velocity for each voxel. In addition, the nearest distance from each voxel to the solid wall is used to approximate the 2D fine-scale velocity, without the need of solving the Stokes equation in 2D for each layer. By this means, the 3D Stokes equation can be simplified to multiple 2D cases that provide the local permeability distribution for the 3D Darcy equation, and thus the computational cost can be significantly reduced. Case studies have been conducted on various samples in different scales. The results demonstrate that the computed 3D permeabilities using finite difference method (based on the Darcy equation) agree well with those using Lattice-Boltzmann method (based on the Stokes equation), and a speedup factor of about O(10) is achieved. The method can be applied to both sandstone and carbonate rocks for fast estimation of block permeability.
Testing of soil aggregate stability by means of laser diffractometer Mastersizer 3000
Authors: Kubát Jan-František , Vrána Michal , Zumr David , Kavka Petr
Published: March 2022

Good stability of soil aggregates is an essential characteristic that positively affects soil health, increases agronomic productivity, decreases susceptibility to soil erosion and can improve carbon sequestration. The most common laboratory procedure for determining soil aggregate stability is a water resistance index (WRI) which is based on a wet sieving method. Within this contribution we introduce a newly developed method which utilizes laser diffraction for estimating the water resistance index of soil aggregates (WRILD). Recently, this newly introduced method has been tested and compared with the Kemper & Rosenau equation. This new method was developed with an emphasis on comparability to the standard sieving procedure performed with the Eijkelkamp wet sieving apparatus. The water stability of the aggregates was tested across five different soil types (haplioc Luvisol, Chernozem, Regosol, Fluvisol, Cambisol). The pH of each sample was measured and according to this value, either hexametaphosphate or sodium hydroxide was used to disrupt the stable aggregates along with ultrasound. The resulting WRILD is determined based on a fraction of undisturbed aggregates recorded for each fictitious sieve size. Initial results show promising agreement between the standard sieving and laser diffractometer methods. The advantage of the latter is a much faster processing time of a large number of samples and their replicates. This new method has a lower variability of results. However, further measurements are needed to validate the method.

This study has been supported by the Grant Agency of the Czech Technical University in Prague, grant No. SGS20/156/OHK1/3T/11 and EC H2020 Project 101000224 (TuDi).
Teleconnection-driven sub-seasonal predictability of extreme events: Relevant case studies
Authors: Domeisen Daniela I.V. , White Christopher J. , Afargan-Gerstman Hilla , Antoine Salomé , Ardilouze Constantin , Batté Lauriane , Camargo Suzana J. , Collins Dan , Ferranti Laura , Infanti Johnna M. , Janiga Matthew A. , Kolstad Erik W. , LaJoie Emerson , Magnusson Linus , Strazzo Sarah , Vitart Frédéric , Wulff C. Ole
Published: March 2022

Extreme weather events have devastating impacts on human health, economic activities, ecosystems, and infrastructure. It is therefore crucial to anticipate extremes and their impacts to allow for preparedness and emergency measures. There is indeed potential for probabilistic subseasonal prediction on timescales of several weeks for selected cases of extreme events that are linked to remote drivers and large-scale teleconnections. We here present a range of case studies, including heatwaves, cold spells, and tropical cyclones, where precursors and global linkages may have improved sub-seasonal predictability. These linkages include teleconnections from the tropics as well as the stratosphere, in addition to circumglobal teleconnections. The considered heatwaves exhibit predictability on timescales of 3-4 weeks, while this timescale is 2-3 weeks for cold spells. Precipitation extremes are the least predictable among the considered extremes. Tropical cyclones, on the other hand, can exhibit probabilistic forecast skill on timescales of  up to 3 weeks,  which tends to be favored by remote precursors such as the Madden-Julian Oscillation. These case studies clearly illustrate the potential for event – dependent advance warnings for a wide range of extreme events globally. The subseasonal predictability of extreme events allows for an extension of warning horizons, can provide advance information to impact modelers, and informs communities and stakeholders affected by the impacts of extreme weather events.