bluuebunny/crossref_metadata_2025 huggingface dataset:
A naive Bayesian method to chase mantle plumes in global tomography models
Authors: de Viron Olivier , Van Camp Michel , Ferreira Ana M.G. , Verhoeven Olivier
Published: March 2022

We propose a quantitative approach to search for mantle plumes in global seismic tomography models without prior assumptions on the associated mantle velocity anomalies. We design detection tests with a reasonable detection threshold while keeping false detections at a level lower than 5%. This is based on naive Bayesian clustering analysis, which is possible thanks to the varimax principal component analysis that provides components that are much more independent than the original number of depths slices in the models. We find that using such independent components greatly reduces detection errors compared to using an arbitrary number of depth slices due to correlations between the different slices.

We detect a wide range of behaviour of the seismic velocity profiles underneath the hotspots investigated in this study. Moreover, we retrieve locations away from hotspots that have a similar seismic velocity profile signature to that underneath some hotspots. Hence, it is not possible to obtain a unique definition of seismic velocity anomalies that are associated with mantle plumes and thus care needs to be taken when searching for mantle plumes using prior assumptions about the velocity anomalies that might be associated with them. On the other hand, we identify a criterion that allows establishing a probability distribution of the seismic velocity profiles that is specific to a sub-list of hotspots and we show that this distribution does not occur significantly elsewhere. Overall, the mantle plume zones identified in our analysis do not appear to surround the Africa and Pacific large low shear velocity provinces (LLSVPs) but are rather within them. This supports the idea that LLSVPs may correspond to bundles of thermochemical mantle plumes rather than to compact, dense piles.
Planetary waves modulating the effect of energetic electron precipitation on polar vortex
Authors: Salminen Antti , Asikainen Timo , Mursula Kalevi
Published: March 2022

During the winter, a strong westerly wind surrounds the cold polar stratosphere, forming the polar vortex. In the northern hemisphere the polar vortex is affected by energetic electron precipitation (EEP) which originates from the magnetosphere and is driven by the solar wind. EEP forms reactive nitrogen and hydrogen oxides, NOx and HOx, which destroy ozone and, thus, affects the radiative and thermal balance in the atmosphere. Several studies have shown that the EEP decreases ozone in the winter polar stratosphere and enhances the polar vortex in the northern hemisphere. This EEP effect on polar vortex is also found to depend on different factors such as the quasi-biennial oscillation (QBO) and sudden stratospheric warmings (SSW). Both the QBO and SSWs are believed to modulate the EEP effect via planetary waves, disturbances originating mainly from the troposphere, but the role of planetary waves in this context has not been studied in detail. In this work we examine the EEP effect on northern polar vortex and its dependence on planetary waves. We use the principal component analysis to examine the intensity and spatial distribution of planetary waves in the northern wintertime stratosphere. We then calculate multi linear regressions to estimate the zonal wind responses to EEP also considering planetary waves. We find that the EEP effect on the northern polar vortex is increased when planetary waves are focused at the equatorward side of the polar vortex, while the overall intensity of planetary waves does not significantly modulate the EEP effect.
Multicomponent seismic acquisition for the characterization of the groundwater system at Kurikka, western Finland
Authors: Malinowski Michal , Heinonen Suvi , Koskela Elina , Laakso Viveka
Published: March 2022

Reflection seismic is indispensable in evaluating depth, lateral extent, and heterogeneity of the shallow aquifers related to e.g., glacial sediments. Kurikka area in western Finland is an example of a complex groundwater system. It is being studied for its potential to supply water to the nearby city of Vaasa (with around ~150000 people and large industries in the area). The confined aquifer is topped with soft lake sediments and clays. Below the clays, a mixture of sands and gravels extends down to the bedrock, which can be as deep as 70-100 m. Felsic rocks (granites, granodiorites) constituting bedrock are weathered, fractured, and faulted. Because of the sparse outcrops, mapping of the bedrock fracture zones was based on gravity data and boreholes. Location, dimension, and connectivity of those fractures constitute a big uncertainty in the groundwater flow modeling.

We performed a multicomponent seismic survey in October 2021 west of the town of Kurikka along 3 seismic profiles in order to characterize the fractured and weathered bedrock, as well as the internal structure of the aquifer and its seal. The seismic profiles were acquired along gravel roads and were crossing the inferred fractures and a zone of a rapid change of bedrock elevation. Besides the geological objectives, we tested the performance of the lightweight Vibroseis source (SeismicMechatronics Lightning) and the operational aspects of the Finnish national pool of seismic instruments (Flex-EPOS) consisting of nodal 3C recorders and 3C geophones (https://wiki.helsinki.fi/display/FLEX/Large-N+Devices). Lightning is an electrically driven seismic vibrator (E-vib) based on the linear synchronous motor principle. It weights ca. 90 kg and can be used in both P- and S-wave mode offering 1.3 and 1.8kN force, respectively, with a full-force sweep frequency of 8-400 Hz (capable of sweeping between 1-1000 Hz at lower force). All profiles were shot in P-wave and SH-wave mode, resulting in a comprehensive and good quality 6C dataset. Lightning source proved to provide useful first-break energy up to 600 m offset. A clear bedrock reflection can be correlated in P-P (vertical source – vertical component) and S-S (horizontal source – crossline component) shot gathers. Prominent reflections were also observed in the sediments, with a broadband frequency response (up to 200 Hz).

The FIN-EPOS and FLEX-EPOS are funded by Academy of Finland (Funding Decisions no. 328984, 328776, 328778, 328779, 328780, 328781, 328782, 328784 and 328786)
Inferring the Cloud Vertical Distribution from Geostationary Satellite Data
Authors: Brüning Sarah , Tost Holger , Niebler Stefan
Published: March 2022

Clouds and their radiative feedback mechanisms are of vital importance for the atmospheric cycle of the Earth regarding global weather today as well as climate changes in the future. Climate models and simulations are sensitive to the vertical distribution of clouds, emphasizing the need for broadly accessible fine resolution data. Although passive satellite sensors provide continuous cloud monitoring on a global scale, they miss the ability to infer physical properties below the cloud top. Active instruments like radar are particularly suitable for this task but lack an adequate spatio-temporal resolution. Here, recent advances in Deep-Learning models open up the possibility to transfer spatial information from a 2D towards a 3D perspective on a large-scale.

By an example period in 2017, this study aims to explore the feasibility and potential of neural networks to reconstruct the vertical distribution of volumetric radar data along a cloud’s column. For this purpose, the network has been tested on the Full Disk domain of a geostationary satellite with high spatio-temporal resolution data. Using raw satellite channels, spectral indices, and topographic data, we infer the 3D radar reflectivity from these physical predictors. First results demonstrate the network’s capability to reconstruct the cloud vertical distribution. Finally, the ultimate goal of interpolating the cloud column for the whole domain is supported by a considerably high accuracy in predicting the radar reflectivity. The resulting product can open up the opportunity to enhance climate models by an increased spatio-temporal resolution of 3D cloud structures.
Interception and groundwater dynamics of an alder forest and a neighbouring wet meadow
Authors: Holik Blanka , Nevezi Csenge , Hlavčová Kamila , Kalicz Péter , Gribovszki Zoltán
Published: March 2022

Riparian vegetation forms have strong dependence on hydrological factors. Forests and meadows in valley locations are strictly protected in many cases. Knowledge of the changes in their water balance in context of climate change is critical in terms of their survival.

We studied the hydrology of a riparian alder forest and a neighbouring wet meadow at the outlet of the Hidegvíz valley experimental catchment (eastern foothills of the Alps). Interception loss (significant element of forest water balance) and groundwater uptake importance were analyzed. LAI and forest structural parameters were measured for calculating interception and remote sensing information were also used. We settled groundwater wells for groundwater level dynamics analysis. Meteorological parameters that we used for this analysis were measured in an open-air plot next to the examined ecosystems.

Remote sensing data is useful for determination of LAI and so vegetation storage capacity dynamically in an interception model. Field interception measurement is important for exact model calibration. Measurements of groundwater levels with high frequency give us the possibility to determine groundwater dynamics and to estimate vegetation water uptake. On the basis of the results, interception loss and groundwater uptake of alder forest are significantly higher, so riparian forests have greater water demand for their survival in the changing climate.

Acknowledgement: Research was supported by TKP2021-NKTA-43 project. Project no. TKP2021-NKTA-43 has been implemented with the support provided by the Ministry of Innovation and Technology of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021-NKTA funding scheme.”
Review on Morphology and Turbulence Characteristics in Meandering Rivers
Authors: Gurugubelli Yatirajulu , Timbadiya Prafulkumar V , Barman Bandita
Published: March 2022

Meandering rivers are one of the most complex earth-surface systems and have a significant impact on riverine ecosystem mechanics. Because of the fascinating intricacy of meander morphodynamics, scholars from various disciplines, from fluid mechanics, fluvial hydraulics, and geomorphology, have been fascinated by meandering rivers. In spite of many years of research still, many processes regarding meandering rivers are not answered. Recent decades of research are reviewed herein in this paper. Scholars and experts have studied about flow features and processes such as a distorted profile of longitudinal velocity, secondary flow, inner and outer banks flow separation, etc., and sedimentological processes such as point bars, bend scour, lateral bed slope, etc. Many of them studied time-mean flow, Reynolds stresses, turbulence intensities (TI), turbulent kinetic energy, quadrant analysis, and turbulence scales, etc. under the effect of meandering bends. Many laboratory experiments are carried out to understand the individual processes under different conditions. Due to the rapid enhancement of soft computational techniques, these experimental data sets can be validated. Some future recommendations are also suggested in the field, laboratory, and numerical modelling.

Keywords: Meandering rivers, secondary flow, Reynolds stresses, turbulent kinetic energy, turbulence scales
Underlying reaction mechanisms support narrowing exemptions of ODS and HFC feedstocks under the Montreal Protocol
Authors: Wei Yiyao , Gao Song
Published: March 2022

As the most effective multinational environmental agreement (MEA), the Montreal Protocol on Substances that Deplete the Ozone Layer has eliminated the production of about 98% of the ozone-depleting substances (ODSs). Moreover, the most recent Kigali Amendment to the Montreal Protocol will phase down the production of hydrofluorocarbons (HFCs) with high global warming potentials. The use of ODSs and HFCs as feedstocks is currently exempted from the control of the Montreal Protocol and its associated amendments because it was falsely assumed that there were no feedstock emissions and that products made from feedstocks were safe in manufacture, use and disposal.

In this paper, we demonstrate a previously missing mechanistic link between ODS and HFC feedstocks and a variety of chemical products that resist environmental degradation, including fluoroplastics and elastomers. We illustrate chemical reaction pathways where specific ODS and HFC gaseous molecules are made into a multitude of macromolecules that pollute the atmospheric, terrestrial and aquatic environments and harm industry workers during the manufacture. For example, the feedstock HCFC-22, itself made from chloroform (an associated feedstock), can be made into polytetrafluoroethylene (PTFE), a fluoroplastic in widespread use. Fluoropolymers’ extreme persistence in the environment and harmful emissions associated with their manufacture and disposal justify curtailing the upstream production of plastics from ODS and HFC feedstocks. We show that a variety of feedstock molecules and their byproducts go into the atmosphere and may alter atmospheric chemical composition.

These reaction mechanisms suggest that ODS and HFC feedstocks be narrowed in their exemptions under the Montreal Protocol, via further amendments and adjustments. Considering also the global warming potential and ozone depletion potential of these feedstocks, this policy response can help mitigate stratospheric ozone depletion, climate change and plastics pollution.
Probabilistic prediction of the time to hard freeze using seasonal weather forecasts and survival time methods
Authors: Roksvåg Thea , Lenkoski Alex , Sheuerer Michael , Heinrich-Mertsching Claudio , L. Thorarinsdottir Thordis
Published: March 2022

In the agricultural sector there is a high interest for forecasts that predict relevant agroclimatic indicators related to heat accumulation and frost characteristics. The forecasts can simplify agricultural decisions related to planting and harvest timing. Motivated by this, we propose a probabilistic forecasting framework for predicting the end of the freeze-free season, or the time to a mean daily near-surface air temperature below 0 °C (here referred to as hard freeze). The forecasts are constructed based on a multi-model seasonal temperature forecast ensemble provided by the Copernicus Climate Data Store. The raw temperature forecast is statistically post-processed through a mean and variance correction. The resulting ensemble is next used as input to a survival analysis model. Survival analysis is a broad statistical field that is commonly used in the field of biostatistics, but rarely used in meteorology.

The forecasting framework is evaluated by predicting the time to hard freeze from October 1 for 1993-2020 for a region in Fennoscandia that covers Norway and parts of Sweden, Finland and Russia. We find that the proposed forecast outperforms a climatology forecast from an observation-based data product at locations where the average predicted time to hard freeze is less than 40 days after the initialization date.

Our work also forms an entry point showing how survival models can be used in general to construct seasonal forecasts for other meteorological events, e.g. the onset of the rainy season or the time to the next drought.
Stochastic sediment transport modeling under the effects of intermittency and anisotropy of turbulent flow
Authors: Wu Meng Jie , Tsai Christina W.
Published: March 2022

Turbulent flow is a chaotic condition filled with vortex structures in the flow. Based on past studies, turbulent bursting events are composed of outward interactions (Q1), ejections (Q2), inward interactions (Q3), and sweeps (Q4). Among these events, ejections (Q2) and sweeps (Q4) significantly contribute to time occupied, momentum flux, and sediment flux from the turbulent coherent structure analysis. In addition, turbulent coherent events were assumed to occur continuously in the past. However, it is noticed that, on average, approximately 90% of the total stress was found within merely 50% of the total sampling time. Furthermore, the earlier works supposed the occurrences of these events are the same, and the change between the two states is uncorrelated. It is found that the occurrences of bursting events are a non-Markovian random process. The flow region can be divided into two parts (the near-bed region and the upper layer) by the spatial gradient of the flow velocity. The flow condition near the bed bottom tends to be anisotropic because of the turbulent structures. As mentioned above, these characteristics (intermittency, memory, and anisotropy) were not considered in past studies. This study proposes a modified Stochastic Diffusion Particle Tracking Model, a stochastic Lagrangian model to describe sediment particle movement. The proposed model integrates these characteristics, such as length-scale and time-scale of coherent events determined from the Direct Numerical Simulation dataset (DNS dataset), to reveal more details of sediment particle motion in the turbulent flow. We obtain the sediment particle trajectory from the model and analyze the anomalous diffusion in sediment transport by calculating the variance of the particle trajectory. As far as we know, extreme flow events such as floods induced by typhoons or heavy rainfalls can be regarded as highly intermittency processes. When a detailed description of the turbulent flow can be made available, we can simulate sediment particle motion more comprehensively under these extreme flow conditions.
Unlocking the potential of ML for Earth and Environment researchers
Authors: Weigel Tobias , Albrecht Frauke , Arnold Caroline , Caus Danu , Grover Harsh , Vlasenko Andrey
Published: March 2022

This presentation reports on support done under the aegis of Helmholtz AI for a wide range of machine learning based solutions for research questions related to Earth and Environmental sciences. We will give insight into typical problem statements from Earth observation and Earth system modeling that are good candidates for experimentation with ML methods and report on our accumulated experience tackling such challenges with individual support projects. We address these projects in an agile, iterative manner and during the definition phase, we direct special attention towards assembling practically meaningful demonstrators within a couple of months. A recent focus of our work lies on tackling software engineering concerns for building ML-ESM hybrids.

Our implementation workflow covers stages from data exploration to model tuning. A project may often start with evaluating available data and deciding on basic feasibility, apparent limitations such as biases or a lack of labels, and splitting into training and test data. Setting up a data processing workflow to subselect and compile training data is often the next step, followed by setting up a model architecture. We have made good experience with automatic tooling to tune hyperparameters and test and optimize network architectures. In typical implementation projects, these stages may repeat many times to improve results and cover aspects such as errors due to confusing samples, incorporating domain model knowledge, testing alternative architectures and ML approaches, and dealing with memory limitations and performance optimization.

Over the past two years, we have supported Helmholtz-based researchers from many subdisciplines on making the best use of ML methods along with these steps. Example projects include wind speed regression on GNSS-R data, emulation of atmospheric chemistry modeling, Earth System model parameterizations with ML, marine litter detection, and rogue waves prediction. The poster presentation will highlight selected best practices across these projects. We are happy to share our experience as it may prove useful to applications in wider Earth System modeling. If you are interested in discussing your challenge with us, please feel free to chat with us.
Lateral flow assessment in laterite terrain for better interventions in sustainable groundwater management
Authors: Narayanan Jyothy
Published: March 2022

Laterite terrain overlying the charnockite bedrock system exhibits greater lateral movement of water as compared to its vertical infiltration into the soil profile due to partial water block. Furthermore, the topographic conditions in such areas play a crucial role in the movement of soil water. The variation in the precipitation pattern, increasing population and urbanization has contributed in reducing the infiltration opportunity time for rainwater. The present study was carried out at Malappuram district of Kerala in India. Though, the study area receives an average annual rainfall of 3 m, yet experiences high baseline water stress during post monsoon season. The research study involves analysis of lateral flow from three different soil profile depths i.e. 0-0.4 m, 0.4-0.8 m and 0.8-1.2 m under two different water inducement techniques. Lateral flow monitoring was carried out in two different experimental set ups in two different sites under simulated rainfall conditions and line source of water application. Variation in the lateral flow was assessed using capacitance based sensors which were calibrated and installed at all the three respective soil profile depths. The study revealed that though the infiltration capacity of laterite soil is quite high but, the major portion of infiltrated water moved as lateral flow without contributing to the groundwater table. It was found that of the total water applied as simulated rainfall about, 10 % accounted as lateral flow from a soil profile depth of 1.2 m. During line source application of water, out of the total lateral flow recorded, the soil profile depths of 0-0.4 m, 0.4-0.8 m and 0.8-1.2 m contributed portions of 52.3 %, 43.78 % and 3.8 % as lateral flow. It was found from the study that the soil physical properties including bulk density, effective porosity and soil texture governed lateral flow in the study area. Thus, the research study emphasizes on enhancing preferential flow in vertical direction through deep rooted flora in the study area.  
First results from an absolute atom interferometry gravimeter at Mt. Etna volcano
Authors: Carbone Daniele , Antoni-Micollier Laura , Ménoret Vincent , Lautier-Gaud Jean , Greco Filippo , King Thomas , Messina Alfio , Contrafatto Danilo , Desruelle Bruno
Published: March 2022

In the framework of the NEWTON-g project, the field version of the Absolute Quantum Gravimeter produced by iXblue (AQG-B) was deployed in the summit crater zone of Mt. Etna volcano (Italy), in the summer of 2020. This is the first absolute atom interferometry gravimeter ever deployed on an active volcano. The device was installed in the facilities of the Pizzi Deneri volcanological observatory (PDN; 2800 m elevation, 2.5 km from the summit craters).
Despite the unfavorable environmental conditions at the installation site and the occurrence of phases of high volcanic tremor, the AQG-B provided high-quality continuous data, suitable for studying volcano-related gravity changes. Indeed, it has been possible to track gravity changes with amplitudes ranging between a few tens and a few hundreds of nm/s2, occurring over a wide range of time scales.
Here, we describe the main features of the AQG-B and the issues that were addressed to allow its deployment in the summit zone of an active volcano. We also present the months-long time series that were acquired in 2020 and 2021, with a special focus on the anomalies likely related to volcanic processes.
Possible solution of global environmental problems: adaptive landscape management
Authors: Balázs Pál , Horváth Adrienn , Berki Imre , Szépligeti Mátyás , Konkoly-Gyuró Éva
Published: March 2022

Traditional, small scale land use based on landscape potential is mostly less harmful to the ecosystem compared to present high production-oriented practices. However, low-intensity techniques are generally under-represented in the present land management system or even forgotten. We reveal these ancient management methods and practices in a western Transdanubian forest-dominated landscape of the Carpathian basin (Őrség) through interviews with local elderly people, literature review, historical map-based long term land use change detection and landscape character assessment. We evaluate the results from the point of view of the question: how these solutions could be helpful for the fight against biodiversity loss or even climate change.

Acknowledgement: Project no. 141576 has been implemented with the support provided by the Ministry of Innovation and Technology of Hungary from the National Research, Development and Innovation Fund, financed under the MEC_R_21 funding scheme.
Soil dynamics at its extremes: insights from cosmogenic and fallout radioactive nuclides
Authors: Egli Markus , Musso Alessandra
Published: March 2022

Soil production and denudation are important and opposing processes that ultimately determine soil formation trajectories and, thus, the landscape. High mountainous areas are geomorphologically active environments and are strongly shaped by the redistribution of sediments and soils. With global warming and the subsequent retreat of glaciers, these processes become increasingly important. New areas having fresh and mostly unweathered glacial till is exposed and soils start to form. The dynamics of soil production and denudation in these high-mountainous landscapes are, however, not yet fully understood. We therefore aimed at exploring the relationship between soil production and denudation at different stages of soil development. This was done by comparing a calcareous and a siliceous soil chronosequence in the central Swiss Alps over the last about 14 kyr. We calculated element mass balances to determine weathering rates and measured short- and long-term erosion rates based on meteoric 239+240Puand10Be. In both chronosequences, the erosion rates were highest in the young soils (on average 5−10 t ha-1 a-1 soil loss). Erosion rates decreased markedly after 3−5 ka of soil development (on average 1−2.5 t ha-1a-1 soil loss) to reach a more or less stable situation after 10−14 ka (on average 0.3–2 t ha-1a-1). Chemical weathering and soil production rates also decreased over time, particularly on the calcareous soil sequence.

Depending on the relief and vegetational development, it takes up to 10 ka to reach soil and slope stability. Despite the very high erosion rates, particularly at the start of soil formation, mineral dissolution and transformation reactions are detected and a high rate of organic matter accumulation is measured. Soil production rates reach under such conditions extreme values. In the early stages of soil development, the parent material mainly drives soil formation while at later stages the vegetation becomes more dominant as it promotes surface stability, complex hydrological pathways and chemical weathering that determine water drainage and retention dynamics.
Impacts of heavy and persistent precipitation on railway infrastructure – insights from the Ahr valley, Germany July 2021
Authors: Szymczak Sonja , Backendorf Fabia , Blauhut Veit , Bott Frederick , Fricke Katharina , Junghänel Thomas , Walawender Ewelina
Published: March 2022

Heavy precipitation events are an important trigger for flash floods and landslides on local and regional scale. In contrast to river floods, the enormous erosion potential in catchment areas contributes significantly to the extent of damage of infrastructure located in the valley floors. Due to the mobilisation of large amounts of sediment and deadwood, entrapment occurs at narrow points, e.g. bridges, which can subsequently lead to high flash flood waves, leading to destruction of transport infrastructure located close to rivers and streams. Considering climate change, such events are supposed to increase in the future. Hence, there is an urgent need to increase traffic resilience to this hazard.

This contribution examines the impact of the heavy precipitation event from 14./15. July 2021 on the railway in the Ahr valley in Rhineland-Palatinate, Germany. Large parts of the railway infrastructure were completely destroyed by the flood event. In a first step, a detailed overview of the climatological and hydrological drivers, by means of spatially high-resoluted distribution of precipitation and peak discharges modelling, is given. The event is than compared to past flash flood events of 1910 and 2016 along the Ahr valley. The second step presents a detailed mapping of the damage that occurred along the railway line based on aerial photographs, and addresses the question of the extent to which the railway infrastructure, especially bridges, contributed to the increase in the flood wave and the erosion potential. Based on the analysis, recommendations for action to foster the resilience of railway infrastructure to flash floods are presented, especially the question what magnitudes and return periods of events future dimensioning of railway infrastructure should be based on.
Data assimilation experiments of a ground-based microwave radiometer network for fog forecast improvement.
Authors: Thomas Guillaume , Martinet Pauline , Brousseau Pierre , Chambon Philippe , Burnet Frédéric
Published: March 2022

While fog can severely affect human activities (air, land and marine transportation), its forecast with current numerical weather prediction (NWP) models stays challenging, especially due to the lack of observations in the atmospheric boundary layer and the misrepresentation of non linear small scale processes. To improve knowledge on fog formation, evolution and dissipation, several instruments have been deployed during the SOFOG3D (SOuth west FOGs 3D experiment for processes study) experimental campaign to provide an unprecedent database of detailed 3D observations. In that context, a network of 8 ground-based microwave radiometers (MWR) provided continuous temperature profiling as well as integrated water vapor and liquid water path measurements during a 6 month period. Additionally, Martinet et al (2020) highlighted large temperature errors in the AROME-France (Application of Research to Operations at Mesoscale) NWP model background profiles during fog forecasts, leading to temperature differences up to 6 K when compared to tower measurements. Nevertheless, this study also demonstrate that the assimilation of MWR observations with a one dimensional variational data assimilation scheme could leads to improved initial conditions. To go further in that direction, MWR temperature profile observations from the SOFOG3D experiment have been added in the AROME-France operational data assimilation system, which uses a three dimensional variational algorithm (3D-Var) and climatological and homogeneous background error covariances (B matrix), to quantify the benefit on operational analyses and forecasts of several fog events. Then, the recently developped ensemble variational (EnVar) data assimilation system has been used to conduct new assimilation experiments. The main advantage of such method is to prescribe a fully flow dependent B matrix which is spatially and temporally coherent with the forecasted meteorological conditions. In consequences, it leads to more realistic increments. The results obtained with the different assimilation experiments will be presented. Firstly, a statistical analysis of the impact on the AROME-France analyses and short-range forecasts against conventional observations will be discussed. Secondly, specific SOFOG3D observations will be used to investigate the benefit on dedicated fog case studies.
Global-scale Changes in Vegetation Resilience Mapped with Satellite Data
Authors: Smith Taylor , Boers Niklas , Traxl Dominik
Published: March 2022

It is theorized that the resilience of natural ecosystems – their ability to resist and recover from external perturbations – can be estimated from their natural variability. We test this hypothesis using a global set of recovery rates from large disturbances derived from satellite vegetation data, and find that the expected theoretical relationships between these empirical recovery rates and the lag-1 autocorrelation and variance indeed hold approximately. The spatial pattern of global vegetation resilience reveals a strong link to both precipitation availability and variability, implying that water plays a first-order role in controlling the resilience of global vegetation.

The resilience of vegetation is not, however, static – global changes in temperature, precipitation, and anthropogenic influence will all impact the ability of ecosystems to adapt to and recover from disturbances. We investigate the global spatial and temporal patterns of changes in resilience using the empirically confirmed metrics – lag-1 autocorrelation and variance – and find spatially heterogeneous long-term (1980s-) trends; recent trends (2000s-) in vegetation resilience are strongly negative across land-cover types and climate zones.
Repeated mapping and geological sampling of Mt Etna’s submerged continental margin: First results from RV Meteor expedition M178
Authors: Gross Felix , Kolling Henriette , Barrett Rachel , Hadré Emma , Heinrich Mirja , Bonforte Alessandro , Gambino Salvatore , Petersen Florian , Morgenweck Lea , Matzerath Peter , Wolf Josephin , Heinrich Sven , Vollert Jannes , Hundsdörfer Marie , Filbrandt Christian , Urlaub Morelia
Published: March 2022

Mt Etna, Europe’s largest active volcano, is located directly on the Sicilian coastline of the Ionian Sea. In addition to frequent Strombolian eruptions, Etna’s south-eastern flank is currently sliding seawards at a rate of several centimetres per year. Over the past decade, scientists from multiple countries have intensely studied the submerged sector of the volcano and its continental margin, with their results showing that the well-known onshore flank instability proceeds far into the sea and can be measured by marine geodetic networks. Nevertheless, the relationship between volcanic activity and deformation of the continental margin is still unclear, and various scenarios – from small-scale disintegration over geological time periods to abrupt catastrophic failure – have been suggested.

During RV Meteor’s expedition M178 (Nov – Dec 2021), we revisited the continental margin offshore Mt Etna and conducted dedicated repeated shallow- and deep-water multibeam surveys. In addition, several gravity cores were recovered from the prominent amphitheatre structure, intra-slope basins, and the proposed southern boundary of Mt Etna’s moving flank. We use the baseline bathymetric data, acquired during RV Meteor’s cruise M86/2 in 2011/2012, to investigate and image changes within the geomorphological and geological setting offshore Etna by comparing them with the new multibeam data. The repeated bathymetry shows minor changes compared to the baseline study, but favours the suggestion of sediment re-deposition in the proximal to distal sectors of the continental margin. Our preliminary results from the sediment record provide evidence for syn- and post sedimentary deformation, with clear indications of compressional and extensional periods at the crest of the prominent amphitheatre structure. Furthermore, sediment cores show that the southern boundary ridge, north of the Catania Canyon, hosts several heavily reworked and disintegrated sediment patches, which indicates active deformation within the intra-slope micro-basins at the crest of the ridge.

The results of this project will increase our understanding of how landslides nucleate in extremely active settings such as offshore Mt Etna. Furthermore, the findings will be used to better assess the hazard potential of the sliding flank of the giant volcano and will feed into numerical modelling of the various scenarios that have been postulated for Mt Etna.
Linking the Deccan lava stratigraphy with the end-Cretaceous extinction and impact – new insights from Rajahmundry
Authors: Hoyer Patrick , Regelous Marcel , Adatte Thierry , Haase Karsten
Published: March 2022

The Deccan flood basalt province in India was erupted within < 1 Myr and overlaps in age with the Cretaceous-Paleogene boundary (KPB) extinction event, and the Chicxulub impact in Mexico. Consequently, the role of Deccan volcanism in the KPB extinction is debated, and it has also been proposed that the Chicxulub impact triggered the largest Deccan lava formations (Poladpur, Ambenali and Mahabaleshwar (PAM)), which represent approximately 70% by volume of the total Deccan and may have been erupted within 500,000 years. Recent geochronological data studies debate whether the onset of the PAM eruptions began at the KPB as consequence of the Chicxulub impact, or whether the PAM lavas were erupted in several pulses, beginning several tens of thousands of years before the KPB (e.g., Sprain et al. 2019, Schoene et al., 2019).

The Rajahmundry Traps on the eastern side of India are believed to represent either the distal ends of voluminous Ambenali and Mahabaleshwar lava flows (e.g., Baksi et al. 1994), or lavas which were erupted locally through fault-controlled fissures unrelated to Deccan volcanism (Manikyamba et al. 2015). In contrast to lavas of the Main Deccan Province, the three separate lava flow units at Rajahmundry are interbedded with sediments, which constrain their age relative to the KPB (Keller et al. 2008; Fendley et al. 2020).

Here we present new major and trace element data for lavas from Rajahmundry and from the Main Deccan Province, and correlate the lavas from Rajahmundry with the younger formations of the Deccan Traps using machine learning algorithms. We find that flows of the Poladpur (lower flow), Ambenali (middle flow) and Mahabaleshwar (upper flow) formations are all present at Rajahmundry, confirming these as an eastward extension of the Deccan Traps. The geochemical classification is consistent with published paleomagnetic and geochronological data for these lavas. Our study shows that some Poladpur lava flows were of sufficient volume and were erupted rapidly enough to flow approximately 1000 km across the Indian subcontinent. The ages of sediments at Rajahmundry imply that eruption of the Poladpur Formation and thus the onset of voluminous PAM volcanic activity began close to the KPB (and Chicxulub impact), and at least the youngest Poladpur flows were emplaced in the Danian.
The Combined Application of Nitrification Inhibitor DMPP and Urea-ammonium Nitrogen Fertilizers Reduces Nitrous Oxide Emissions from a Paddy Soil
Authors: Li Dongjia , Li Siping , Liu Rui
Published: March 2022

A common approach to reduce N loss is inclusion of inhibitors with the fertilizer formulation. 3,4-dimethylpyrazole phosphate (DMPP) is the most efficient nitrification inhibitor to date. Most studies to date on the inhibitory effects have focused on the edaphic and environmental variables affecting DMPP efficacy, but very little is reported with respect to the N fertilizer formulation which DMPP applied with. Therefore, the present study aimed to evaluate the synergic effect of urea-ammonium N fertilizers (UA) applied with DMPP on nitrous oxide (N2O) and ammonia (NH3) emissions from a restricted paddy soil. N fertilizer (UA) was applied at a rate of 100 mg N kg-1dry soil, and DMPP application rates were set as 0 (CK), 0.5% (D1) and 1.2% (D2) of the total N. All treatments were incubated under 20℃ and 60% of water-filled pore space (WFPS) over a 10-d incubation period. The dynamic changes in mineral N contents, N2O fluxes and cumulative NH3 emissions were monitored during the incubation. The results showed that combined application of UA and DMPP dramatically reduced net nitrification rate (Nnet) and N2O emissions. DMPP decreased Nnet by 56.8% (D1), 68.2% (D2) compared with UA application alone, respectively. The total N2O emissions were decreased by 34.2% (D1) and 47.3% (D2), respectively. NH3 volatilization was significantly increased after DMPP addition, which might be attributed to the increase of NH4+ concentration during the incubation. The cumulative NH3 volatilization of DMPP treatments increased by 116 - 166% during the incubation period. Our results suggest that DMPP significantly limited nitrification and reduced N2O emissions when applied with UA fertilizers, but this could lead to considerably NH3 volatilization after application. 
Destabilizing the Earth’s thermostat: Riverine alkalinity responses to climate change
Authors: Lehmann Nele , Stacke Tobias , Lehmann Sebastian , Lantuit Hugues , Gosse John , Mears Chantal , Hartmann Jens , Thomas Helmuth
Published: March 2022

Alkalinity generation from rock weathering is thought to modulate the Earth’s climate at geological time scales. Here, we use global alkalinity data paired with consistent measurements of erosion rates to develop an empirically-based model for riverine alkalinity concentration, demonstrating the impact of both erosion (i.e. erosion rate) and climate (i.e. temperature) on alkalinity generation, globally. We show that alkalinity generation from carbonate rocks is very responsive to temperature and that the weathering flux to the ocean will be significantly altered by climate warming as early as the end of this century, constituting a sudden feedback of ocean CO2 sequestration to climate. While we anticipate that climate warming under a low emissions scenario will induce a reduction in terrestrial alkalinity flux for mid-latitudes (-1.3 t(bicarbonate) a-1 km-2) until the end of the century, resulting in a temporary reduction in CO2 sequestration, we expect an increase (+1.6 t(bicarbonate) a-1 km-2) under a high emissions scenario, causing an additional short-term CO2 sink at decadal timescales.
Applications with ceilometer with depolarization ratio measurement
Authors: Tuononen Minttu , Lehtinen Raisa , Roininen Reijo
Published: March 2022

Ceilometers are robust, standalone, and cost-effective lidar-based remote sensing instruments. Conventionally, ceilometers are used in aviation to detect cloud base heights. Ceilometers can also be used for atmospheric profiling, and the applications using profile information are becoming more common, as well as operative networks of profiling instruments. Development of new ceilometers with additional measurement capabilities enables more thorough sensing of the atmosphere, covering a variety of applications. The focus of this presentation is on the different application possibilities that a new lidar ceilometer with a depolarization measurement capability offers.

High-quality attenuated backscatter profiles are used for cloud, boundary-layer, and elevated aerosol-layer profiling. The further addition of the depolarization ratio profiling allows more straightforward and detailed analysis of the current atmospheric conditions. With these measurements, it is not only possible to increase the public safety operationally, but also to investigate atmospheric phenomena in more detail. The newly developed instrument operates with 910.55 nm wavelength and can measure both attenuated backscatter and depolarization ratio.

The differentiation of liquid cloud droplets and ice crystals and the differentiation of rain/drizzle and snowfall is now more accurate and easier with the depolarization measurement. In addition, the detection of the melting layer and potential icing conditions are easier to identify. The structure of the boundary layer and elevated aerosol layers can be monitored in more detail and for example the detection of volcanic ash is a new and potentially very beneficial application with ceilometer with depolarization. The depolarization ratio measurement using a new wavelength can be also used to investigate other different aerosol characteristics and type, and for example to group different pollen types.

In this presentation, we show how different conditions can be distinguished – from hydrometeor and precipitation type analysis to measurement examples of wildfire smoke and dust. Specifically, we will show results of ceilometer measurements in La Palma, Spain, during the volcanic eruption that occurred in the end of 2021. In addition, more accurate identification of potential icing conditions is discussed.
Resolving canopy contribution to mixed satellite NDVI values in a sparse dry forest
Authors: Wang Huanhuan , Muller Jonathan , Tatrinov Fedor , Rotenberg Eyal , Yakir Dan
Published: March 2022

Remote sensing (RS) techniques have great potentials for land surface monitoring. Nevertheless, for most low to moderate resolution satellites, the problem of mixed pixels with information from the vegetation of interest and the background surfaces can cause significant biases in the signals and their interpretations. This is especially so in low-density forests and semi-arid ecosystems.

This work was motivated by the observed mismatch between satellite data (Landsat 8; nadir view) and tower-based Skye (90° angle of view) radiometer, in a low-density semi-arid pine forest (the Yatir forest in southern Israel) during 2013-2019. The two records showed opposite seasonal cycles in canopy NIR reflectance. We hypothesized that the different contributions of the surface components in the footprint areas of the two sensors could explain these observations and that accounting for this effect can help resolve the actual canopy NDVI values. 

An image classification algorithm was derived from Unmanned Aerial Vehicle (UAV) multispectral images to estimate the fraction and reflectance of the three main surface components: canopy, shaded areas, and bare soil. The results showed 30% and 95% canopy fractions in the Landsat 8 and Skye footprints, respectively. Therefore, the Landsat 8 signal was strongly influenced by soil reflectance, which is, in turn, sensitive to soil moisture level. The Skye mainly reflected canopy properties, including pigment content and canopy structure.

Based on these results, we developed an approach to correct the sunlit and shaded soil contributions to the mixed Landsat 8-pixel NDVI, and retrieve the canopy NDVI. This approach relied on canopy fraction, sun elevation angle and the pre-determined NDVI values of the non-canopy components derived at the tower area. The retrieved canopy NDVI values were consistent with those of the high-resolution UAV-based canopy NDVI and independent of variations in the observed satellite NDVI values. These results demonstrated a new approach for improving the use of satellite NDVI to monitor the activities of forest canopies in sparse ecosystems, as well as the need for its application.