bluuebunny/crossref_metadata_2025 huggingface dataset:
Granulated biochar-based NPK fertilizer and its impact on nutrient leaching, plant growth and soil-borne N2O emissions
Authors: Grafmüller Jannis , Kray Daniel , Kammann Claudia , Mühe Marie E. , Schmidt Hans-Peter , Hagemann Nikolas
Published: February 2023

Biochar amendments to fertilized soils are an important step towards more resource-efficient practices in agriculture by limiting the amounts of nutrients being leached to water bodies or transformed to the potent greenhouse gas (GHG) nitrous oxide (N2O). Biochar was often amended to the soil separately to the fertilizer application. Alternatively, biochar and nutrient bearing salts or minerals can be blended and aggregated, e.g., granulated prior to soil application. However, the impact of this practice on biochar effects on nutrient availability, leachability and soil-borne N2O emissions is so far largely unexplored. Here, we present data on the effects of a granulated, biochar-blended mineral NPK fertilizer applied to a sandy soil in two different greenhouse pot trials on white cabbage and spinach, respectively. In the white cabbage (Brassica oleracea convar. Capitata var. Alba) experiment, the biochar blended NPK fertilizer reduced nitrogen leaching by 30 to 45% compared to the pure NPK fertilized control following two simulated heavy precipitation events. Results in a similar range were obtained when pure, milled biochar was homogeneously mixed with pure NPK fertilizer in the soil as a further control. The reduced nutrient loss in biochar-amended pots may have contributed to increases in cabbage head biomass of 14% for the granulated biochar NPK fertilizer and 34% for the loose mix of milled biochar with pure NPK fertilizer, when compared to the NPK fertilizer control without biochar. In the spinach (Spinacia oleracea, no precipitation events) experiment, the biochar-blended granulated fertilizer increased the marketable fresh spinach yields by 5% while the mixture of milled biochar and pure NPK fertilizer in the soil increased yields by 13% compared to the control without biochar, respectively. The analyses of GHG emissions that were measured during this experiment allows to comprehend whether these yield increases were also caused by a lower volatilization of fertilized nitrogen as N2O-N. With these two experiments, we provide insights on how biochar-blended fertilizers interact with plants and the soil system and how biochar could be used in agricultural practices to increase nutrient use efficiencies, i.e., the environmental costs per unit of yield produced, by reducing the undesired loss of nutrients from soil in combination with yield increase.
Conductivity and Temperature as indicators of hydrothermal activity: A comparison of two submarine volcanoes (Greece)
Authors: Dura Ana , Mertzimekis Theo J. , Nomikou Paraskevi , Hannington Mark , Petersen Sven
Published: February 2023

The presence of active hydrothermal vent fields near residential areas and their possible link to volcanic activity pose a potential natural hazard to the environment, to society, and to the economy. Despite the importance of risk assessment and mitigation, the monitoring of volcanic activity is hindered by the remoteness and extreme conditions of underwater volcanoes. By developing a mathematical model for geological and physical processes in these environments we shed light on the underlying dynamics of chemical products emitted from the vents and point to the underlying mechanisms that govern potentially hazardous, underwater volcanic environments. Santorini and Nisyros both belong to the Hellenic Volcanic Arc but appear to have different underlying mechanisms. The Generalized Moments Method (GMM) was applied to data gathered from the Northern Caldera of Santorini and the Nisyros caldera, Avyssos, for the purpose of this work, where we focus on the high-frequency recorded CTD data (Conductivity, Temperature, Depth) in the water column over the hydrothermal vents. The data from Santorini were collected in 2017 using an Autonomous Underwater Vehicle (AUV) during the POS510 mission led by GEOMAR, while the data from Nisyros were gathered with the help of a Remotely Operated Vehicle (ROV) in 2010, during the Nautilus expedition.
Climate of the 6th Century based on the Fully Forced Regional Climate Model COSMO-CLM over the Eastern Mediterranean and the Nile Basin
Authors: Zhang Mingyue , Hartmann Eva , Wagner Sebastian , Adakudlu Muralidhar , Xoplaki Elena
Published: February 2023

The interactions and feedbacks between climate stress and social systems are currently the focus of interest for the scientific community and the general public. Understanding how paleo societies responded to extreme climate conditions is important for gaining insight into current and future climate concerns. The East Mediterranean (EM) and the Nile River basin (NR) are ideal areas for scientific and historical studies and modelling experiments due to the abundance of proxy and historical data. The 6th century AD is of particular interest from both a historical and scientific perspective, as it coincides with a period of prosperity for the Eastern Byzantine Empire and political stability, but which also experienced a plague pandemic and significant climate variability in parallel or as a result of a major cluster of volcanic eruptions. To investigate these events and the climate variability in the 6th century in more detail, a transient paleo-simulation is carried out with the appropriately adjusted regional climate model COSMO-CLM (COSMO 5.0 clm16). The regional climate model is driven by the global MPI-ESM-LR at 0.44° for the last 2500 years. The state-of-the-art external forcings of the CMIP6 compliant Earth System Model comprise of volcanic (stratospheric aerosol optical depth), orbital (eccentricity, obliquity, longitude), solar (irradiance), land-use (leaf area index and plant coverage) and greenhouse-gas (CO2 equivalent) changes, implemented in the regional climate model. The simulated temperature and precipitation will be compared with those of other CMIP6 models, and proxy records. This research will provide a comprehensive interpretation of the regional climate and its impacts during the 6th century AD in the Mediterranean. ReferenceJungclaus, J. H., Bard, E., Baroni, M., Braconnot, P., Cao, J., Chini, L. P., Egorova, T., Evans, M., González-Rouco, J. F., Goosse, H., Hurtt, G. C., Joos, F., Kaplan, J. O., Khodri, M., Klein Goldewijk, K., Krivova, N., LeGrande, A. N., Lorenz, S. J., Luterbacher, J., Man, W., Maycock, A. C., Meinshausen, M., Moberg, A., Muscheler, R., Nehrbass-Ahles, C., Otto-Bliesner, B. I., Phipps, S. J., Pongratz, J., Rozanov, E., Schmidt, G. A., Schmidt, H., Schmutz, W., Schurer, A., Shapiro, A. I., Sigl, M., Smerdon, J. E., Solanki, S. K., Timmreck, C., Toohey, M., Usoskin, I. G., Wagner, S., Wu, C.-J., Yeo, K. L., Zanchettin, D., Zhang, Q., and Zorita, E.: The PMIP4 contribution to CMIP6 – Part 3: The last millennium, scientific objective, and experimental design for the PMIP4 past1000 simulations, Geoscientific Model Development, 10, 4005–4033, https://doi.org/10.5194/gmd-10-4005-2017, 2017.
The contribution of stochastic vegetation dynamics to overall model uncertainty of the global carbon sink
Authors: Layritz Lucia Sophie , Neupane Prabha , Rammig Anja
Published: February 2023

The terrestrial carbon sink plays a central role in the global carbon cycle, providing a strong negative feedback on anthropogenic climate change. However, it is also one of the more uncertain elements when simulating past and future carbon dynamics, mainly due to the challenge of modeling biological and ecological complexity across scales. One possible strategy, taken by the dynamic vegetation model LPJ-GUESS, is to use stochastic processes to describe key ecological processes, whose mechanistic modeling is still challenging (e.g. tree mortality, establishment, seed dispersal and disturbance).Such introduced randomness can propagate through the model in various ways and may result in a final model output that is probabilistic in nature as well. Internal stochasticity can thus be seen as an additional source of model uncertainty, which so far has rarely been investigated systematically.We perform global simulations of terrestrial carbon dynamics with LPJ-GUESS and quantify the resulting stochastic uncertainty. We find that stochasticity-induced uncertainty is a relevant share of overall uncertainty, comparable in magnitude to scenario uncertainty in some instances. When introducing stochastic processes into Earth system models, the resulting additional uncertainty should therefore be something to always be aware of.
A cross-discipline approach to examine the physical links between Weather in Space and the Lower Atmosphere
Authors: Taylor Matthew , Floberghagen Rune , Strømme Anja , Rast Michael , Baddeley Lisa , Blanc Michel , Donovan Eric , Doornbos Eelco , Haagmans Roger , Kauristie Kirsti , Kepko Larry , Milan Steve , Opgenoorth Hermann , Partamies Noora , Stockdale Tim , Stolle Claudia
Published: February 2023

Earth’s atmosphere provides the background for the “sea of plasmas” surrounding Earth via its Ionosphere and the upper and middle Atmosphere, providing an interface layer through which a broad diversity of solar-terrestrial energy transfer processes takes place. Developing an integrative understanding of global geospace energy transfer processes affecting this layer is a major scientific challenge with important societal implications. The disciplines covering this interaction have a large, diverse and active international community, with significant expertise and heritage in the European Space Agency and Europe. Several ESA directorates have activities directly connected with this topic, and an ESA Heliophysics Working group has been appointed by several ESA Directors, under the direction of the ESA Director General, to work on optimizing synergies and to act as a focus for discussion, inside ESA, of the scientific interests of the Heliophysics community.Very recently, a Forum at the International Space Science Institute was set up, involving some of the above WG, to look towards developing a deeper understanding of the solar-terrestrial interactions between the Ionosphere and the upper- and middle atmosphere, thus possibly enabling the detection of signatures by natural and anthropogenic hazards.This presentation will provide a brief introduction to ongoing internal ESA cross discipline approaches, and then note some of the outcomes of this recent ISSI forum to set out a pathway to address this intriguing topic.
Observational Analysis of Small-scale Structures in the Earth's Magnetosheath
Authors: Harvey Rebecca , Hu Qiang
Published: February 2023

Magnetic flux ropes with a wide range of scale sizes generally have high magnetic helicity, a magnetohydrodynamic (MHD) quantity that characterizes the knottedness of the field lines that can be used to identify flux rope structures. The identification and analysis of structures moving across boundaries such as the Earth's bow shock will give insight into how their properties change across this boundary as well as further our understanding of the interrelation between these structures. Recent spacecraft missions are returning higher time resolution data than before, allowing for more advanced studies of this phenomenon. Using high time-resolution data from the Magnetospheric Multiscale (MMS) mission and Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission, we identify small-scale flux ropes using wavelet analysis and determine how they change across boundaries. Wavelet analysis of single-spacecraft data can produce better resolved time and spatial information that will complement other methods of flux rope identification. Wavelet transforms are performed across hours-long intervals, organized by the orbit configuration of the spacecraft. The resulting spectrograms are then searched to identify small-scale structures. A number of parameters, including duration, scale size, maximum magnetic field, and average plasma temperature of the flux rope intervals identified are also recorded and summarized. Comparing the values of magnetic field, plasma beta, and other parameters at the corresponding times and locations leads to interpretations for the flux rope events such as whether they are compressed, decelerated, or undergo any other changes as they evolve.
Estimating the seismicity of Venus by scaling Earth’s seismicity
Authors: van Zelst Iris , Maia Julia , Spühler Moritz , Plesa Ana-Catalina , Garcia Raphaël F. , Ghail Richard , Gülcher Anna J. P. , Horleston Anna , Kawamura Taichi , Klaasen Sara , Lognonné Philippe , Orgel Csilla , Panning Mark , Sabbeth Leah , Smolinksi Krystyna
Published: February 2023

With the selection of multiple missions to Venus by NASA and ESA planned to launch in the coming decade, we will greatly improve our understanding of Venus as a planet. However, the selected missions cannot tell us anything about the seismicity on Venus, which is a crucial observable to constrain the tectonic activity and geodynamic regime of the planet, and its interior structure. Here, we provide new, preliminary estimates of Venus’ global annual seismic budget and the expected frequency of venusquakes per year. We obtain this estimate by scaling the seismicity of the Earth recorded in the CMT catalogue. We test different potential scaling factors based on e.g., the difference in mass, radius, potential seismogenic volume, etc. We also sort the earthquakes into their respective tectonic settings, which allows us to exclude irrelevant tectonic settings present on Earth, but most likely not on Venus from our analysis. This enables us to present a range of potential seismic budgets and venusquake frequencies per tectonic setting on Venus.  This then provides a new estimate of the potential amount of seismicity on Venus. However, it is uncertain how valid this simple scaling approach is from Earth to Venus. Indeed, previous attempts of scaling the volcanism of Earth to Venus (Byrne & Krishnamoorthy, 2022; Van Zelst, 2022) resulted in numbers that aligned with independent estimates, but are still unconstrained and hard to verify until the announced missions fly. Therefore, in order to provide a more robust and holistic view of Venus’ anticipated seismicity, estimates using various different, independent methods should ideally be considered.To provide exactly that, we set up the ISSI team ‘Seismicity on Venus: Prediction & Detection’. This is an interdisciplinary team of experts in seismology, geology, and geodynamics. Together we aim to assess the seismic activity on Venus from a theoretical and instrumental perspective. In addition to presenting our preliminary seismicity estimates from scaling Earth to Venus, we therefore also use this contribution to briefly introduce the team and its goals and present the preliminary findings from our first, week-long, dedicated in-person meeting aimed at further characterising Venus’ seismicity. ReferencesByrne, Paul K., and Siddharth Krishnamoorthy. "Estimates on the frequency of volcanic eruptions on Venus." Journal of Geophysical Research: Planets 127.1 (2022): e2021JE007040.van Zelst, Iris. "Comment on “Estimates on the Frequency of Volcanic Eruptions on Venus” by Byrne & Krishnamoorthy (2022)." Journal of Geophysical Research: Planets (2022): e2022JE007448.
Seasonal and annual kinematics of active rock glaciers under different climate regimes in the Western USA
Authors: Handwerger Alexander L. , Kluetmeier Camryn , Brencher George , Munroe Jeffrey S.
Published: February 2023

Rock glaciers are common landforms in many alpine permaforst landscapes that play an important role in alpine hydrology and landscape evolution, principally through the release of seasonal meltwater and the downslope transport of coarse material. Here, we use satellite-based interferometric synthetic aperture radar (InSAR) to identify and monitor rock glaciers in the Western USA. We focus on the movement of active and transitional rock glaciers in Utah (Uinta, Wasatch, and La Sal Mountains), and Wyoming (Wind River Mountains) between 2015 and 2022. Using the new framework established by the International Permafrost Association (IPA) Action Group, we identified 255 active and transitional rock glaciers in the ~3500 km2 Uinta Mountains, 45 rock glaciers in the ~200 km2 La Sal Mountains, 55 rock glaciers in the ~135 km2 Wasatch Mountains, and 120 rock glaciers in the ~3000 km2 Wind River Mountains. These rock glaciers currently occur under different climatic regimes based on data from the 30 year (1991-2020) normal Parameter-elevation Relationships on Independent Slopes Model (PRISM). The La Sals and Wasatch are warmer and wetter with a mean annual air temperature (MAAT) of ~3.0± 1.9 ˚C and  2.7 ± 1.1 ˚C and a mean annual precipitation (MAP) of ~92 ± 13 cm and ~130 ± 17 cm, respectively, whereas the Uintas and Wind Rivers are cooler and drier with a MAAT of ~0.24 ± 1.4 ˚C and  -0.87 ± 1.4 ˚C and a MAP of ~87 ± 11 cm and ~81 ± 10 cm. The mean line-of-sight (LOS) velocities for individual rock glaciers range from ~1 to 10 cm/yr. We also examined the time-dependent relationship between the motion of the rock glaciers and local climatic drivers such as temperature and precipitation. We found that rock glaciers exhibit seasonal and annual velocity changes, likely driven by liquid water availability (from snowmelt and rainfall), with accelerated motion during summers and during wetter years. Our findings demonstrate the ability to use satellite InSAR to monitor rock glaciers over large areas and provide insight into the environmental factors that control their kinematics.
Ecogaming for circular economy
Authors: Elefteriu Crina
Published: February 2023

The basis for our current „Ecogames in my curriculum” Erasmus+ project is teaching students the benefits of circular economy and how to use it.The circular economy aims to minimize waste and pollution by using resources in a more efficient and sustainable way. This approach can help to reduce the negative environmental impacts of economic activity and improve economic efficiency. During our first LTT in Romania we taught students how to implement circular economy to support sustainable development. These are some examples of how we played to learn circular economy:For reducing waste (one of the key principles of a circular economy is to minimize waste by keeping resources in use for as long as possible), we organized a Circular Economy Fair where our students sold various objects crafted through strategies such as reuse, repair, refurbishment, and recycling.
For promoting resource efficiency, our students created a wind turbine, they also taught the foreign students invited to the workshop how to create a photovoltaic panel by using resources more efficiently and minimizing waste. Both activities involved strategies such as designing products and systems that use fewer resources and are easier to repair or recycle.
For supporting economic growth, our students presented their eco business plans since a circular economy can provide economic benefits by creating new business opportunities and promoting innovation. Our students focused on how this can help to create jobs and stimulate economic growth.
For improving environmental sustainability, we invited our foreign guests to plant an oak for each country involved in the project. By conserving natural resources we can reduce greenhouse gas emissions, thus lowering the environmental impacts of economic activity by minimizing waste and pollution.
For enhancing social welfare, we proposed a food waste lesson followed by a gardening workshop. We organized a lesson with Romanian and foreign students promoting changes in consumer behaviour to reduce food waste requires, by using better food storage and preservation techniques, and improved food recovery and donation programs. Food waste is a major problem in developed countries, not only a financial burden, but it also has a negative environmental impact. After the lesson, each team received a gardening kit with researched seeds donated by the Seeds Bank from Suceava.
            Moreover, by reducing the amount of resources and materials that need to be produced, circular economy initiatives can help to reduce the cost of resources and services, making them more accessible to those with limited incomes. Finally, circular economy initiatives can also help to promote social inclusion by creating a more equitable access to resources and services, which can help to reduce poverty and inequality.
Effect of grain-size evolution on the lower mantle dynamics
Authors: Paul Jyotirmoy , Golabek Gregor , Rozel Antoine , Tackley Paul , Katsura Tomo , Fei Hongzhan
Published: February 2023

Grain-size evolution is a crucial controlling factor for the lower mantle rheology. Notably, one order of grain size change can produce a viscosity change of the order of 100-1000 times. As diffusion creep dominates in the lower mantle, grain growth of lower mantle mineral assemblages, e.g., bridgmanite and ferropericlase, increase viscosity considerably. It has been quite challenging to constrain the grain-size evolution parameters for lower mantle mineral assemblages until recently; a new high-pressure experimental study (27 GPa, cf. Fei et al, 2021, EPSL) parameterised them. The experimental data found a slower grain growth of bridgmanite-ferropericlase phases than of the upper mantle mineral phases, e.g., olivine and spinel. Using the most updated knowledge of grain-size evolution, we develop 2-D spherical annulus numerical models of self-consistent mantle convection using the finite volume code StagYY and explore how grain-size evolution affects the lower mantle dynamics. We test our models with different heterogeneous grain size evolution and composite rheology that evolve self-consistently for 4.5 billion years. Our preliminary models show the self-consistent formation of thermochemical piles at the base of the core-mantle boundary where the grain size is maximum (~3 times than the surroundings). Even though the bridgmanite-ferropericlase grain growth is slower, a slight increase in the grain size of thermochemical piles can make them ~100-1000 times viscous, subsequently helping them to achieve morphological stability over billion years. In some of our models, we find sweeping stability of the piles for ~500 million years. 
Sudden shallow dyke intrusion at São Jorge Island (Azores) after 60 years of repose
Authors: D'Araújo João , Hooper Andy , Lazecky Milan , Sigmundsson Freysteinn , Ferreira Teresa , Silva Rita , Gaspar João , Marques Rui
Published: February 2023

Eruptions at long-inactive volcanoes are usually preceded by days to months of unrest as magma migrates gradually to shallower depths. This is built into plans by civil protection agencies for societal response. Here we show that at São Jorge, Azores, after 60 years of repose, magma reached almost the surface in a vertical dike intrusion within a few hours of the seismicity onset with no previous precursory signals. São Jorge lies in a rift zone where extensional stress is expected to be built over time to accommodate magma at depth. Recent eruptions at São Jorge have produced pyroclastic density currents, and the potential for an eruption to occur with little warning poses a significant risk. Deformation associated with the event reached other neighboring islands over a distance of at least 45 km away from São Jorge. Deformation was high on the first day of activity (>50 mm within March 19-20) and significantly decreased afterward. The combined analysis of GNSS and InSAR data allows using a model of segmented rectangular dislocations with multiple patches for data inversion. A maximum opening of 1.7 m at 4-6 km depth is inferred from the modeling. We interpret the cause of the initial vertical shallow injection to be due to host rock failure conditions triggered by deviatoric stresses. We investigate why lateral spreading of the dike occurred soon after the initial injection. Using a FEM simulation, we show how the tension at the tip of a vertical propagating dike is high at the start and decreases with shallower depths, reaching similar levels of tension found at the lateral parts of the dike and increasing the probability of lateral propagation.
Effect of anthropogenic climate change on explosive cyclogenesis cases in Europe
Authors: Ginesta Mireia , Flaounas Emmanouil , Yiou Pascal , Faranda Davide
Published: February 2023

Mid-latitude storms are essential features of atmospheric variability in the cold season. The subsequent damages are caused by high wind speeds and heavy precipitation. Among such events, explosive cyclones can lead to extreme impacts when they make landfall. Climate change is affecting the underlying characteristics of such types of extremes. Being able to understand the way it modifies their dynamics is of great importance. In this work, we assess the influence of anthropogenic climate change on observed explosive cyclones in an Extreme Event Attribution framework using a large ensemble dataset. We evaluate three storms that hit different parts of Europe: Xynthia in February 2010, Alex in October 2020, and Eunice in January 2022. We use three ensembles of 35 members of the Community Earth System Model (CESM). We compare two periods of 6-hourly data: present-day climate [1991-2001] and future climate [RCP8.5 scenario, 2091–2101]. We find analogues of the trajectories of the three storms before their highest intensity in both periods. We do that by tracking all cyclones in the dataset and selecting the cyclone tracks that have the minimum Euclidean distance in km from the trajectories of Xynthia, Alex, and Eunice. We explore the characteristics of the analogues of the trajectories in both periods such as frequency of explosive cyclogenesis and intensity to evaluate whether the dynamics of the storms have been affected by climate change. We further compare the analogues in terms of precipitation and low-level wind in the regions of impact.
Operations Eclipse Sequencing in Multipurpose Dam Planning
Authors: Giuliani Matteo , Arnold Wyatt , Zatarain Salazar Jazmin , Carlino Angelo , Castelletti Andrea
Published: February 2023

A resurgence of dam planning and construction is under way in several river basins where untapped hydropower potential could meet growing energy demands. In Africa, more than 300 new hydropower projects are under consideration. Yet, hydropower expansion is a contentious issue given the uncertainty in water and energy demand as well as the negative impacts of these infrastructures on other sectors. Despite calls for a more comprehensive evaluation of hydropower projects, most dams continue to be planned with traditional methods that neglect interdependencies between planning and management and the cumulative impacts of multiple new dams. Here, we use the transboundary Zambezi Watercourse in southern Africa to present a novel dam planning approach that integrates sequencing of planned reservoirs with adaptive, multipurpose operations to address increasing and competing demands for water, energy, and food in the region.Results show how seeking compromise through operations while constructing dams early improves environmental and irrigation objectives by 50% and 80%, with an 8% loss in hydropower compared to an operation and sequencing strategy that singularly maximizes hydropower. Alternatively, seeking compromise only through delayed dam construction yields modest environmental and irrigation improvements of 6% and 9%, respectively, with a 22% loss in hydropower. Our findings indicate that while additional hydropower capacity reduces structural energy deficits, operating policies emerge as the main driver of human-environmental tradeoffs. Consequently, traditional single-objective operating policy selection may lead to erroneous perceptions of tradeoffs across infrastructure options. The robustness of this result is tested under an ensemble of stochastic hydrologic projections where environmental flow and irrigation deficits are found more sensitive to operations than shifts in water availability. The predominance of operating policies is relevant for improving multi-objective dam planning in other river basins already fragmented by dams built in the 20th century.
Modelling mixed scenarios of canopy and soil spectral reflectance to improve SOC prediction
Authors: Abdelbaki Asmaa , Milewski Robert , Chabrillat Sabine
Published: February 2023

Three and four times as much carbon is stored in Earth's soil as organic matter, about 60-80%, compared to what is found in the atmosphere and terrestrial plants. A quantifiable fraction of soil organic matter is soil organic carbon (SOC), which is a key property of soil quality. Since the advent of optical remote sensing technologies and especially with the development of soil and imaging spectroscopy, empirical statistical approaches have often been employed to link the spectral signatures with soil properties. Common approaches are indirect modelling through the multivariate statistical algorithms and machine learning algorithms, where correlation processes and nonlinear relationships between variables are taken. An alternative, to these methods, is forward radiative transfer modelling (RTM) or physical modelling that predicts the spectral reflectance of soils in the solar domain (0.4–2.5 μm) in different scenarios. This approach nowadays is mostly used for modeling wet soils and potentially inferring soil moisture content from soil reflectance, but not used for retrieving other properties such as mixed vegetation content and soil properties such as organic carbon content. In this research supported by WORLDSOILS project, we aim to couple a multilayer radiative transfer model of soil reflectance (MARMIT) to soil-leaf-canopy model (SLC-1D RTM) based on LUCAS soil spectral library (SSL) to simulate reflectances of mixed soil-vegetation scenarios as function of water, vegetation and SOC content. In the integrated model called MARMIT-SLC, changes in the spectral reflectance of the soil surface are considered that include the occurrence of soil moisture, dryness, in addition to the effects of early green crops and dry crop residues. This development may improve the coverage and accuracy of SOC predictions based on remote sensing data. For this, upscaling simulations over a large spatial scale of landscapes are performed. Preliminary results show that the accuracy of SOC predictions obtained from the laboratory's VNIR-SWIR spectra based on LUCAS 2009 soil datasets have increased. Although the RTM approach has been developed systematically to validate the suitability of the improved soil algorithm for global soil mapping, there are challenges in model evaluation and validation of results due to the lack of ground data availability.Keywords: soil spectroscopy, RTM, MARMIT model, SLC model, Leaf area index, fractional vegetation cover, SOC.
Characterizing forest structure using LiDAR and multi-frequency SAR remote sensing
Authors: Böhm Marianne , Zehner Markus , Schellenberg Konstantin , Bueso-Bello José-Luis , Rizzoli Paola , Schmullius Christiane , Dubois Clémence
Published: February 2023

Describing forest structure is fundamental to understanding forest ecology and calculating biomass estimations. To enable its characterization with large spatial coverage, we investigate data recorded by airborne LiDAR and three different radar frequencies over a deciduous broadleaf forest at the Hainich National Park in central Germany. This study aims at distilling the microwave frequencies and polarisations that most closely relate to structural metrics extracted from the LiDAR point clouds, and are therefore most promising for extending spatial or temporal coverage.The LiDAR point clouds, which are provided openly by the Thuringian State Office for Land Management and Geoinformation, were processed to five structural metrics at 25 m x 25 m pixel size. These metrics comprise an estimation of fractional cover based on vegetation return numbers,  an intensity-based fractional cover approach (Hopkinson & Chasmer 2009), the skewness and standard deviation of the height distribution, as well as the the vertical complexity index as defined by van Ewijk (2011). These metrics were compared to terrain-corrected backscatter of phenologically matching scenes from three different sensor frequencies: an X Band scene from DLR TerraSAR-X, C Band from Copernicus Sentinel-1, and L Band from JAXA ALOS-2. The scenes represent leaf-off conditions. To reduce misleading factors, the analysis was limited to areas with moderate slope angles below 10 degrees. Subsequently, regression models between the lidar metrics and backscatter intensities were built.First results from bivariate correlations indicate the best match between ALOS-2 HV and fractional cover (r²=0.41) as well as standard deviation (r²= 0.43). Among the metrics, fractional cover is associated most closely with backscatter in all frequencies: the highest correlation coefficients amount to 0.37 for X Band (VV), 0.22 for C Band (VH), and 0.41 for L Band (HV), respectively. In general, C Band exhibits the lowest pairwise correlations with most density metrics, compared to L- and X Band. The poster will show the results of multivariate regression models and discuss which combination of frequencies and polarizations is best suited for the derivation of specific forest structure parameters at larger scales.---Hopkinson, C., & Chasmer, L. (2009). Testing LiDAR models of fractional cover across multiple forest ecozones. Remote Sensing of Environment, 113(1), 275–288. DOI:10.1016/j.rse.2008.09.012van Ewijk, K. Y., Treitz, P. M., & Scott, N. A. (2011). Characterizing Forest Succession in Central Ontario using Lidar-derived Indices. Photogrammetric Engineering & Remote Sensing, 77(3), 261–269. DOI: 10.14358/PERS.77.3.2
Numerical simulation and analysis of transient Ekman boundary layers using a stochastic turbulence model
Authors: Klein Marten , Schöps Mark Simon , Medina Méndez Juan Alí , Schmidt Heiko
Published: February 2023

Atmospheric boundary layers (ABLs) govern the atmosphere–surface coupling and are therefore of fundamental relevance for Earth’s weather and climate system. Key challenges in modeling and simulation of ABLs arise from the emerging spatio-temporal variability that manifests itself by fluctuating transport processes and intermittency on multiple scales (e.g. [1,2]). Observed flow features are the result of interacting inertial, Coriolis, buoyancy, and viscous forces, acting on all relevant scales of the turbulent flow. Small-scale processes, even if nonuniversal in nature, are usually not resolved due to cost constraints but modeled based on justified physical or empirical relations with the resolved scales, neglecting expensive backscatter (e.g. [3]). This issue is addressed here by a stochastic forward model, the so-called one-dimensional turbulence (ODT) model [4], which allows to preserve small-scale information in a feasible manner. In the ABL, ODT autonomously evolves flow profiles for prescribed initial and boundary conditions. Turbulent advection is modeled by a stochastically sampled sequence of mapping events that punctuate the deterministic advancement of molecular-diffusive processes and Coriolis forces. The model aims to reproduce turbulent cascade phenomenology, resolved along a notional vertically oriented line-of-sight, respecting fundamental physical conservation principles. The dynamical complexity of the model arises from a physically based feedback of the evolving flow state on the stochastic sampling procedure.In this study, ODT is utilized as standalone tool for the numerical simulation of fluctuating wind velocity and temperature profiles in temporally developing neutral and stably stratified ABLs [5]. Comparison with available reference data shows that the model is able to reasonably reproduce conventional low-order but also detailed flow statistics for fixed model parameters. The model exhibits scale-selective buoyancy damping, but is unable to completely capture the relaminarization under prescribed, but developing, very stable conditions. This can be attributed to the model’s resistance against leaving the fully developed turbulent state. Forthcoming research addresses fluctuations and intermittency effects. For the latter, an event-based clustering approach is presented that aims to identify turbulent cascade events across flow regimes, yielding new possibilities for the analysis and prediction of turbulent time series.References[1] L. Mahrt. Annu. Rev. Fluid Mech. 46:23–45, 2014.[2] V. Boyko, and N. Vercauteren. Boundary-Layer Meteorol. 179:43–72, 2021.[3] S. S. Zilitinkevich, T. Elperin, N. Kleeorin, I. Rogachevskii, and I. Esau. Boundary-Layer Meteorol. 146:341–373, 2013.[4] A. R. Kerstein, and S. Wunsch. Boundary-Layer Meteorol. 118:325–356, 2006.[5] M. Klein, and H. Schmidt. Adv. Sci. Res. 19:117–136, 2022.
Predicting Glacier Terminus Retreat Using Machine Learning
Authors: Shionalyn Kevin , Catania Ginny , Trugman Daniel , Felikson Denis , Stearns Leigh
Published: February 2023

While a majority of mass loss from the Greenland Ice Shelf is attributed to glacial terminus retreat via calving, the superimposed force factors of the ice-ocean interface create a challenge for physically modeling terminus change. Here we use time series of environmental and glacial data, input as features into a machine learning regression model, to forecast terminus retreat for marine-terminating glaciers in Greenland. We then identify the critical features that most impact a glacier’s likelihood of retreat using feature importance analysis. We further analyze the heterogeneous outcomes for individual glaciers to classify them by their terminus change profile.  By better understanding the parameters impacting glacial retreat, we inform physical models to reduce uncertainty in mass change projections.
Investigating ice crystal formation and growth in wintertime stratus clouds over the Swiss Plateau (CLOUDLAB project)
Authors: Lohmann Ulrike , Henneberger Jan , Ramelli Fabiola , Spirig Robert , Fuchs Christopher , Miller Anna , Omanovic Nadja , Zhang Huiying , Bühl Johannes , Gaudek Tom , Ohneiser Kevin , Radenz Martin , Seifert Patric , Baettig Philipp , Hervo Maxime , Leuenberger Daniel
Published: February 2023

Wintertime stratus clouds over the Swiss Plateau can last for days.  They dissipate either due to airmass changes, absorption of solar radiation during the day, or after glaciation when a sufficiently large number of cloud droplets freezes. After formation, the ice crystals grow in an ice-supersaturated environment via vapor deposition until they are large enough to sediment from the cloud as drizzle or freezing drizzle.To better understand how quickly ice crystals of various habits grow in real clouds with turbulence, we conduct glaciogenic seeding experiments in wintertime stratus clouds over the Swiss Plateau in our project CLOUDLAB[1]. During these experiments, a drone releases silver iodide (AgI) particles into the cloud, upwind of our measurement site, and we use various ground-based remote sensing and in-situ cloud and aerosol instruments to detect the microphysical changes induced by seeding. Preliminary results from the first CLOUDLAB field campaign proved that our method successfully allows us to detect the seeding signal in the cloud radar. In addition to our field measurements, we conduct numerical model simulations with ICON at different horizontal resolutions and different seeding particle concentrations to understand which seeding AgI concentration is theoretically needed for partial or full glaciation of the cloud, i.e. how fast the ice crystals grow at the expense of the evaporating cloud droplets due to the Wegener-Bergeron-Findeisen process.First results will be presented in this talk.
[1] https://cloudlab.ethz.ch/
Comparitive performance of two quality control algorithms for personal weather station rainfall data in Amsterdam Metropolitan Area
Authors: de Vos Lotte , El Hachem Abbas , Seidel Jochen , Bárdossy András
Published: February 2023

The accurate estimation of precipitation is still one of the major challenges in hydrology. One fairly new approach to improve rainfall quantification is the use of so-called opportunistic sensors (OS), i.e. sensors that were not designed to provide high-quality rainfall data at a larger scale, but can be used for that purpose. One type of OS are personal weather stations (PWS) that are owned by private users. They typically comprise one or a set of low-cost devices that record meteorological variables such as air temperature and rainfall. The number of PWS has increased over the past years and the high number of rain gauges offers potential to improve rainfall estimates. OS have also raised scientific interest in the recent years. In October 2021, the EU COST Action CA 20136 “Opportunistic Precipitation Sensing Network” (OPENSENSE) was launched with the aim to bring together researchers in the field of OS and to build a global opportunistic sensing community. Furthermore, EUMETNET recently released a dataset containing data of PWS in Europe for 2020 from MetOffice WOW and Netatmo to support the development of PWS quality control tools.Compared to traditional rain gauge networks, PWS provide data in high temporal and spatial resolution but with low quality, since they are often not installed and maintained according to professional standards. Therefore, these data require a thorough quality control (QC) and filtering before they can be used for applications such as areal precipitation estimates. Two different QC algorithms have been published by de Vos et al. (2019) and Bárdossy et al. (2021). These are available in the OPENSENSE GitHub environment (https://github.com/OpenSenseAction). In this study, we apply these two aforementioned QC algorithms on four 24-hour periods, containing convective or homogeneous rain events, from the same PWS dataset for the Amsterdam Metropolitan Area, and validate the outcome using a gauge-adjusted radar product as reference. The characteristics and relative performance of the QC algorithms are presented, thus providing aid for prospective users to decide which of these QC algorithms is best suited for their purpose.References:Bárdossy, A., Seidel, J., & El Hachem, A. (2021). The use of personal weather station observations to improve precipitation estimation and interpolation. Hydrology and Earth System Sciences, 25(2), 583-601de Vos, L. W., Leijnse, H., Overeem, A., & Uijlenhoet, R. (2019). Quality Control for Crowdsourced Personal Weather Stations to Enable Operational Rainfall Monitoring. Geophysical Research Letters, 46(15), 8820-8829.
Ground-based volcanic ash detection with low-cost sensors – a case study at the 2021 Cumbre Vieja eruption
Authors: Pacheco Jose , Henriques Diogo , Oliveira Sérgio , Moutinho Alexandra , Viveiros Fátima , Henriques Diamantino , Hernández Pedro , Pèrez Nemesio
Published: February 2023

The Tajogaite eruption of Cumbre Vieja volcano, in 2021, was a basaltic fissure eruption characterised by a variety of eruptive styles ranging from the predominantly strombolian activity, to lava fountaining, ash emission and effusive activity. The eruption lasted nearly 3 months, produced an extensive lava field and about 45.106 m3 of tephra. Although its intensity varied throughout the entire duration of the eruption, the eruptive plume had a typical height of about 3500 m asl and reached a maximum of 8500 m asl just hours before the end of the eruption, on the 13th of December. Ash is, therefore, a significant hazard to consider not only during the eruption, but also on the post-eruption phase.To measure ash in the air around the volcano, during the last stage of the eruption and the following weeks, an experiment was devised based on a proximal network of several ground-based low-cost sensors, measuring suspended particulate matter (PM10, PM2.5) concentration, air temperature, and relative humidity.The results showed that, during the documented period, the daily mass concentration of particulate matter in the air reproduced the peak on the eruptive column high at the end of the eruption. After the eruption several significant resuspension events were detected simultaneously in several stations; in addition, after the eruption, a major event of “calima” dust intrusion largely exceeded all recorded eruptive events. Overall, even after the eruption, the 24-hour average exposure to PM2.5 surpassed the guidelines of the World Health Organization.  This work was partially funded by FCT – Fundação para a Ciência e Tecnologia, under project SONDA - Synchronous Oceanic and Atmospheric Data Acquisition (PTDC/EME-SIS/1960/2020) and INTERREG MAC under the project VOLRISKMAC-II - Fortalecimiento de las capacidades de I+D+i para el desarrollo de la resiliencia frente a emergencias volcánicas en la Macaronesia.
Influence of soil pore structure on the rate of microbial oxygen consumption
Authors: Chakraborty Poulamee , Guber Andrey , Kravchenko Alexandra
Published: February 2023

O2 availability is one of the main factors influencing microbial processing of soil carbon and nitrogen and their cycling, and soil pore structure is what drives micro-scale patterns of O2 availability. The diffusivity of O2 is known to be a function of soil porosity and moisture content. However, the actual distribution of O2 in the soil is a product of dynamic interactions between physical (O2 diffusion) and microbial (O2 consumption) processes and is influenced by the soil pore structure. Measurements of gas diffusivity can be achieved via several laboratory techniques, while the determination of O2 consumption by microorganisms is challenging. The objectives of this study are, first, to propose a method for measurement of microbial O2 consumption under steady-state conditions in saturated soil and near saturated soil, and, second, to quantify the rate of O2 consumption in soil materials with contrasting pore structures but similar microbial compositions. The proposed method is based on Fick’s second law of diffusion, given as , where R(z) is an O2 consumption term, C is the concentration of O2, and Ds is the effective molecular diffusion coefficient of O2. The equation was solved for R(z) under steady-state conditions (near saturated soil) where the flux (J)=0. Two soil materials with contrasting pore structures, namely dominated by > 30 μm Ø pores (i.e., large-pore soil) and by < 10 μm Ø pores (i.e., small-pore soil), were prepared. The O2 profile was measured to the depth of 1 cm in the two materials under saturated and near-saturated conditions using O2 microsensor (Unisense, Aarhus, Denmark). As expected, the O2 diffusion was higher in large-pore soil as compared to the small-pore soil, however, the estimated rate of volumetric O2 consumption was also higher in the large-pore soil as compared to the small-pore soil. This finding supports the notion that large pores provide a better micro-environment for soil microorganisms stimulating their activity with subsequent increases in O2 consumption. Our ongoing work builds on these findings and explores the rate and spatial distribution patterns of O2 diffusion and microbial O2 consumption in soils with contrasting pore structures in the presence of plant residues.