bluuebunny/crossref_metadata_2025 huggingface dataset:
Imaging measurements of volcanic BrO using Fabry-Pérot interferometer correlation spectroscopy
Authors: Nies Alexander , Fuchs Christopher , Kuhn Jonas , Heimann Jaro , Bobrowski Nicole , Platt Ulrich
Published: March 2022

Imaging of atmospheric trace gases gives insights into physical and chemical processes in the atmosphere on the scale of seconds and metres. This is of particular importance when observing point sources with highly variable emission, like smoke stacks or volcanoes, and the chemical processes therein. In particular for volcanic plume measurements, instruments are required that not only combine a high spatio-temporal resolution with a high trace gas selectivity, but that are also sufficiently robust and compact to be used under field conditions and in remote locations.

Imaging Fabry-Perot interferometer (FPI) correlation spectroscopy (IFPICS) is a novel imaging technique for atmospheric trace gases. Atmospheric trace gas column densities are quantified with a high spatial and temporal resolution by matching the periodic spectral transmission of a FPI to the close to periodic vibronic absorption features of the target trace gas in the ultraviolet or visible wavelength range. So far, IFPICS has been applied to volcanic sulphur dioxide (SO2) imaging and laboratory measurements of formaldehyde (HCHO).

In this study, we present measurements of volcanic bromine monoxide (BrO) from a field campaign at Mt. Etna in July 2021. BrO is a very reactive species and thus only present in low amounts (some tens of ppt) in volcanic emission plumes, however, it is important as (1) indicator for degassing processes and (2) agent in plume chemistry. We discuss the challenges associated with separating the weak absorption signal of BrO (typical optical density around 10-3) from other effects within the complex environment of the volcanic plume. The camera prototype has a detection limit of 1x1014 BrO molec cm-2 at a time resolution of 10 s and a spatial resolution of approximately 200 x 200 pixels. Using a second IFPICS instrument for SO2 measurements, an estimate for the BrO to SO2 ratio in the plume is given.
Combined discrete and continuous gravity measurements at Vulcano Island (Aeolian Archipelago, Italy)
Authors: Greco Filippo , Carbone Daniele , Contrafatto Danilo , Messina Alfio Alex , Berrino Giovanna
Published: March 2022

We present the preliminary results of combined discrete and continuous gravity measurements, carried out at Vulcano Island (Aeolian Archipelago, Sicily, southern Italy), in the period October 2021 - January 2022. The gravity observations have been aimed at investigating the dynamics of the volcanic-hydrothermal system, during an interval when significant changes in chemical properties, temperatures and emission rates of La Fossa crater fumaroles were observed.

Campaigns of gravity measurements were carried out at Vulcano on an annual basis, between 1982 and 2014. The gravity network initially included 11 benchmarks and grew through time. For the period considered here, the discrete gravity measurements were repeated twice (October and November 2021) on a network consisting of 19 benchmarks. The network is linked to an external reference station, situated in Milazzo (Sicily north coast), that has been a site of absolute measurement since 1990. In order to obtain information on the time scales of the volcanic and hydrothermal processes able to induce bulk mass changes, three stations for continuous gravity measurements were installed in October 2021.

Comparison between campaign data collected in 2014 and in October 2021 reveals a gravity decrease affecting the whole volcano, with a maximum amplitude of about -100 microGal in the area of La Fossa. No significant gravity changes were observed between October and November 2021. On the other hand, continuous gravity observations showed high frequency variations affecting only one of the three stations, thus indicating that they are due to fast-evolving and local processes, occurring within shallow sources. Transient signals also appear in the time series from the three stations during Very Long Period (VLP) events.

Our findings indicate that the combined use of discrete and continuous gravity measurements is a promising tool for studying the volcano-hydrothermal system of Vulcano and mitigating potential hazards.
Spatial Markov-Process Modeling of Solute Dispersion with Log-Normal Velocity Distributions
Authors: Cirpka Olaf Arie , Stettler Marie-Madeleine , Dentz Marco
Published: March 2022

Spatial Markov processes have become efficient methods to simulate solute transport in heterogeneous formations. The approach follows solute particles from one observation plane to the next, assuming that the particle velocity of an individual travel-distance increment depends on the velocity of the preceding increment. The approach can be seen as a correlated continuous-time random walk with deterministic spatial jumps, or as correlated time-domain random-walk method. The first-order Markov property allows simulating the pre-asymptotic regime with a limited set of rules. The transition of velocities from one step to the next can be formulated by a discrete transition matrix, or approximated with a parametric joint distribution. For the latter, we use the bivariate log-normal distribution. For this distribution, we show that the pdf of the normalized flux-weighted slowness (= inverse velocity) is identical with pdf of the volume-weighted normalized Eulerian velocity. For a flux-weighted injection, we derive analytical expressions of the travel-time variance and associated dispersion coefficient both for discrete travel-time increments and in the continuous limit of infinitesimally small increments over the same distance. The analytical solution reproduces the first-order solution of perturbative methods in the limit of small velocity variances at the limits of small and very large travel distances, but it provides natural extensions for large variances of the log-velocity. In the case of a volume-weighted injection, the mean log-slowness relaxes exponentially to the asymptotic mean, while the variance of log-slowness remains constant. The associated analytical expressions for injection into the volume involve integrals requiring numerical quadrature. We compare the derived expressions with particle-tracking simulations in 3-D heterogeneous media with isotropic exponential covariance function testing variances of log-conductivity up to 5. We observe that the variance of the log-velocity scales linearly with that of log-conductivity and that the integral scale of the log-velocity remains fairly constant. The parameters of the spatial-Markov-process model can be related to parameters of the log-conductivity field with minimal adjustments to first-order results while being applicable to cases of large velocity variability.
Stress characterization in the Canadian Shield: Complexity in stress rotation
Authors: Wang Wenjing , Schmitt Douglas
Published: March 2022

NE-SW stress compression in the Western Canadian Sedimentary Basin was discovered in the pioneering borehole breakout observations of Bell and Gough (1979). However, all of these and subsequent stress direction indicators are from the Phanerozoic sediment veneer, while the state of stress in the underlying craton remains unexplored. With the emergent demands on geothermal energy and wastewater and CO2 disposal, however, the state of stress in the cratons can no longer be safely ignored. To address this problem, we analyze various vintages of geophysical logs obtained from a serendipitous wellbore-of-opportunity drilled to 2.4 km in NE Alberta.  The profile of breakout orientations inferred from image and caliper logs exhibits a distinct rotation in breakout orientations changing from N100°E at 1650-2000m to N173°E at 2000-2210m and, finally, to N145°E at the bottom from 2210-2315m. The deepest measurement is consistent with the many observations in the overlying sediments. The heterogeneous breakout orientations at different depth intervals possibly indicate a heterogeneous in-situ stress field in the Precambrian craton. In addition, however, there is a strong correlation between the metamorphic textures and the breakout orientations suggesting that anisotropic strength may play an important role.  Using a recently developed algorithm we show that these observations can indeed be explained by foliation-controlled failure patterns in such anisotropic metamorphic rocks (Wang & Schmitt, accepted).  Models demonstrate that the observed breakout rotations can be produced under uniform stress orientations with failure slip planes controlled by the textured metamorphic rocks with anisotropic strength. This modeled stress field indicates that the stress field in the Canadian Shield where the far-field SH azimuth is at N50°E and the region is under normal/strike-slip faulting regime, is coupled with that in the overlying sedimentary basin.
Flow redistribution and backwater rise due to brush accumulation upstream of logjams with a lower gap
Authors: Follett Elizabeth , Schalko Isabella , Nepf Heidi
Published: March 2022

Engineered logjams with a gap at the bed are used in engineering practice to provide natural flood management and ecological benefits while preserving river connectivity at base flow. In addition, logjams with a gap at the bed form naturally in small streams with river width less than log length. The accumulation of wood pieces acts as a porous obstruction, and the distribution of flow through and beneath a jam with a lower gap satisfies a two-box, momentum-based model constrained by drag generated in the jam, momentum loss in flow through the lower gap, and net pressure force. Accumulation of brush and fine material upstream of logjams occurs naturally as small wood pieces and leaves are transported to the river channel. However, the impact of accumulated upstream material on logjam-generated increase in backwater rise presents a potential concern for long term maintenance of engineered logjam projects. We present recent results demonstrating that initial accumulation of wood pieces upstream of a jam with a lower gap has little impact on backwater rise, but backwater rise increased during a simulated flood cycle as wood pieces blocked the lower gap. The effect of varying brush size and shape and impact on flow redistribution between the jam and gap is examined.
From energy to (soil organic) matter
Authors: Gunina Anna , Kuzyakov Yakov
Published: March 2022

This work proposes a new view of soil organic matter (SOM) formation: microorganisms use most of the organics entering the soil as energy rather than as a source of carbon (C), while SOM accumulates as a residual by-product because the microbial energy investment in its decomposition exceeds the energy gain. Considering the annual sequestration of C from litter into SOM of 0.4-5% of the total SOM pool, the energy input is equivalent to 1-10% of the total energy of SOM. Thus, more than 90% of the energy added to the soil by plants is lost in microbial transformation, with SOM representing the residual fraction. The conversion of plant litter accumulates approximately ~ 2% of the energy per unit of persisting plant organic matter. This is the proportion of biochemically stable litter-derived compounds and microbial necromass that get accumulated, while oxidized compounds are completely decomposed or recycled. As a result, SOM has more energy per unit C than plant residues, but the availability of that energy is low. This is because SOM composition is more diverse with a non-regular structure compared to plant residues and thus requires a wider range of enzymes to break it down.

The microbial transformation of plant residues into SOM is a never-ending continuum governed by processes such as mineralization, recycling, microbial necromass, and residue accumulation, all of which determine the energy content, fluxes, and nominal oxidation state of C (NOSC) values of the residual litter and the resulting SOM. NOSC and energy content of SOM are narrower in range than litter, with an average NOSC of -0.3, and a higher energy per unit C. Meanwhile, the NOSC values of available compounds (mainly low molecular weight) released from decomposed polymers play a role in the partition of C between catabolism and anabolism in microorganisms. They also affect the energy investment of microorganisms in nutrient mining from SOM.

The conversion of rhizodeposits and plant litter, considered to be the main sources of C in soil, therefore needs to be re-examined from an energy perspective, including energy quality and availability. This would also require the assessment of energy loss and conservation, as almost all microbial processing is directed towards energy acquisition rather than actual C demand. The small amount of plant-derived C and energy that persist in the form of SOM is only an intermediate phase to ensure energy fluxes in the soil system. Thus, the transformation of rhizodeposits and plant litter represents a process of utilization of the energy stored in them, while SOM is the residual material that persists because its microbial utilization is energetically inefficient.
Simulating the FIP effect in coronal loops using a multi-species kinetic-fluid model.
Authors: Poirier Nicolas , Lavarra Michael , Rouillard Alexis , Blelly Pierre-Louis , Réville Victor , Verdini Andrea , Velli Marco , Buchlin Eric , Indurain Mikel
Published: March 2022

We investigate abundance variations of heavy ions in coronal loops. We develop and exploit a multi-species model of the solar atmosphere (called IRAP’s Solar Atmospheric Model: ISAM) that solves for the transport of neutral and charged particles from the chromosphere to the corona. We investigate the effect of different mechanisms that could produce the First Ionization Potential (FIP) effect. We compare the effects of the thermal, friction and ponderomotive force. The propagation, reflection and dissipation of Alfvén waves is solved using two distinct models, the first one from Chandran et al. (2011) and the second one that is a more sophisticated turbulence model called Shell-ATM. ISAM solves a set of 16-moment transport equations for both neutrals and charged particles. Protons and electrons are heated by Alfvén waves, which then heat up the heavy ions via collision processes. We show comparisons of our results with other models and observations, with an emphasis on FIP biases. This work was funded by the European Research Council through the project SLOW_SOURCE - DLV-819189.
The Climate Impact Explorer, a free online tool providing sectoral impact projections for a wide range of scenarios down to the subnational level
Authors: Lejeune Quentin , Pfleiderer Peter , Beck Thessa , Menke Inga , Kropf Chahan , Sauer Inga , Schleussner Carl
Published: March 2022

This online climate impact tool was developed as part of a collaboration with the Network for Greening the Financial System (NGFS) aiming at improving the understanding of how physical risks from climate change impact the macro-economic and financial systems. Interactions with stakeholders from the NGFS enabled to identify how tailored climate impact information could facilitate this understanding by fulfilling the following criteria: (i) provision of projections for other scenarios that those classically used in climate science, more tailored to the financial and macro-economic systems, (ii) for many sectoral indicators with a specific interest for economic damages from climate impacts, (iii) with a comprehensive estimate of the associated uncertainty and especially its upper bound, and (iv) in a spatially explicit way but also aggregated over administrative units.

As a result, the Climate Impact Explorer provides impact projections aggregated over all continents, countries and their provinces for many sectoral and economic damage indicators, as well as several global warming levels and various emissions scenarios, including those co-developed with the NGFS. The associated uncertainty ranges encompass both the global climate sensitivity to emissions and the response of local impacts to global warming. The tool also displays maps of projected impacts for 1.5, 2, 2.5 and 3°C of global warming over all countries in the world. All time series plots, maps and underlying data can be freely downloaded.

No dedicated simulations were run to produce the underlying data, instead we made use of the 0.5°x0.5° impact projections from ISIMIP2b, as well as existing runs by the CLIMADA model at a resolution of 5 arcmins for the economic damage indicators. The employed methodology can be applied to any emissions scenarios for which the resulting global warming trajectories are available.

The tool has already been used by central banks and other financial institutions or companies, and has proved of high interest for stakeholders from developing countries where little impact information is available. Efforts are currently ongoing to use information from the Climate Impact Explorer for stress testing of macro-economies to climate physical risks. This should hopefully lead to further improve the understanding of data needs and overall help increase the resilience of economies and the financial system to climate change.
On the Generation of Pi2 Pulsations due to Plasma Flow Patterns Around Magnetosheath Jets
Authors: Katsavrias Christos , Raptis Savvas , Daglis Ioannis , Karlsson Tomas , Georgiou Marina , Balasis George
Published: March 2022

We report observations of a magnetosheath jet followed by a period of decelerated background plasma. During this period, THEMIS-A magnetometer showed abrupt disturbances which, in the wavelet spectrum, appeared as prominent and irregular pulsations in two frequency bands (7.6–9.2 and 12–17 mHz) within the Pi2 range. The observations suggest—for the first time to our knowledge— that these pulsations were locally generated by the abrupt magnetic field changes driven by the jet’s interaction with the ambient magnetosheath plasma. Furthermore, similar pulsations, detected by THEMIS-D inside the magnetosphere with a 140 s time-lag (which corresponds to the propagation time of a disturbance traveling with Alfvénic speed), are shown to be directly associated with the ones in the magnetosheath, which raises the question of how exactly these pulsations are propagated through the magnetopause.

This research is co-financed by the Greece and the European Union (European Social Fund - ESF) through the Operational Program “Human Resources Development, Education and Lifelong Learning 2014–2020” in the context of the project ULFpulse (MIS: 5048130). C. Katsavrias and I.A. Daglis aknowledge the European Union's Horizon 2020 research and innovation programme “SafeSpace” under grant agreement No 870437. S. Raptis and T. Karlsson acknowledge support from SNSA grant 90/17.
Retreat of the Rhine Glacier from Lake Constance: Sedimentological and geochemical evidence from a deep-basin sediment core
Authors: Schaller Sebastian , Böttcher Michael E. , Buechi Marius W. , Epp Laura S. , Fabbri Stefano C , Gribenski Natacha , Harms Ulrich , Krastel Sebastian , Liebezeit Alina , Lindhorst Katja , Marxen Hanna , Raschke Ulli , Schleheck David , Schmiedinger Iris , Schwalb Antje , Vogel Hendrik , Wessels Martin , Anselmetti Flavio S.
Published: March 2022

The modern, over 250-m-deep basin of Lake Constance represents the underfilled northern part of an over 400-m-deep, glacially overdeepened trough, which reaches well into the Alps at its southern end. The overdeepening was formed by repeated glacial advance-retreat cycles of the Rhine Glacier throughout the Middle to Late Pleistocene. A seismic survey of Lake Constance revealed a Quaternary sediment fill of more than 150 m thickness representing at least the last glacial cycle. The stratified sedimentary fill consists at the base of ice-contact deposits on top of the molasse bedrock, overlain by glaciolacustrine to lacustrine sediments. During the successful field test of a newly developed, mid-size coring system ("HIPERCORIG"), the longest core (HIBO19) ever taken in Lake Constance was retrieved with an overall length of 24 m. The sediments recovered consist of a nearly continuous succession of lacustrine silts and sands including more than 12 m of Late Glacial sediment at the base. 14 lithotypes were identified through petrophysical and geochemical analyses. In combination with a 14C- and OSL-based age-depth model, the core was divided into three main chronostratigraphic units. The basal age of ~13.7 ka BP dates the base of the succession back to the Bølling-Allerød interstadial, with overlying strata representing a complete and thick Younger-Dryas to Holocene succession. The sediments offer a high-resolution insight into the evolution of paleo-Lake Constance from a cold, postglacial to a more productive, warm Holocene lake. The Late Glacial succession is dominated by massive, m-thick sand beds reflecting episodic sedimentation pulses. They are most likely linked to a subaquatic channel system originating in the river Seefelder Aach, which is, despite the Holocene drape, still apparent in today's lake bathymetry. The overlying Holocene succession reveals a prominent, several cm-thick, double-turbiditic event layer representing the most distal impact of the Flimser Bergsturz, the largest known rockslide of the Alps that occurred over 100 km upstream the river Rhine at ~9.5 ka BP. Furthermore, lithologic variations in the Holocene succession document the varying sediment loads of the river Rhine and the endogenic production representing a multitude of environmental changes.

 
Combining dendroecology and remote sensing to assess how late spring frosts affect European beech forests
Authors: Vitali Alessandro , Tonelli Enrico , Malandra Francesco , Camarero J. Julio , Colangelo Michele , Nolè Angelo , Ripullone Francesco , Carrer Marco , Urbinati Carlo
Published: March 2022

Climate-extreme induced disturbances such as summer droughts and late spring frosts (LF), can affect productivity and tree growth in temperate forests. In this study we investigated how LFs affect canopy cover and radial growth in European beech (Fagus sylvatica) forests along an elevation gradient at four sites in the Italian Apennines. We combined tree-ring and remote-sensing data to analyse the vulnerability and recovery capacity of beech populations to LFs. We computed population and individual climate-growth relationships to test their responses at different elevation. Using climatic records, we reconstructed LF events and assessed their immediate and carry-over effects on growth. We also checked the role played by spatial and structural variables as drivers of LF rings occurrence at population and individual scales. We computed Normalized Vegetation Index (NDVI), Enhanced Vegetation Index (EVI) and LAI (Leaf Area Index) using satellite images to evaluate the post-LF canopy recovery. The growth reduction in LF-affected trees ranged from 36% to 84%. We detected a negative impact of LF on growth only during the year of LF occurrence, with growth recovery in 1-2 years after the event. Water deficit during the previous and current summers and cold spring temperatures are the main factors limiting beech growth. LFs affected stands feature low NDVI, EVI and LAI values until late June. Frost rings formation is enhanced at mid rather than low and high elevations, induced by spring leaf phenology. An increasing frequency of LF events could alter the resilience of mountain beech forests, but nowadays they show a high recovery capacity and no legacy effects. A broader geographic area, especially in marginal sites, and the use of other tree-ring variables (anatomy, isotopes), could improve the assessment of post-LF resilience in beech forests. Such improvement would help managers in preserving forest ecosystem services.
Short-term hydrological response of soil after wildfire in a semi-arid landscape covered by Macrochloa tenacissima (L.) Kunth
Authors: Zema Demetrio Antonio , Plaza-Àlvarez Pedro Antonio , Mijan Uddin Sm , Parhizkar Misagh , Lucas-Borja Manuel Esteban
Published: March 2022

A proper monitoring and management of semi-arid landscapes affected by wildfire is needed to reduce its effects on the soil hydrological response in the wet season. Despite ample literature on the post-fire hydrology in forest soils, it is not well documented how the hydrologic processes respond to changes in vegetation cover and soil properties of semi-arid lands (such as the rangeland and areas with sparse forests) after wildﬁre. To fill this gap, this study evaluates soil hydrology in a semi-arid soil of Central Eastern Spain dominated by Macrochloa tenacissima (a widely-spread species in Northern Africa and Iberian Peninsula) after a wildfire. Rainfall simulations were  carried out under three soil conditions (bare soil, burned and soils with unburned vegetation) and low-to-high slopes, and infiltration, surface runoff and erosion were measured. Infiltration rates did not noticeably vary among the three soil conditions (maximum variability equal to 20%). Compared to the bare soil, the burned area (previously vegetated with M. tenacissima) produced a runoff volume lowered by 27%. In contrast, in the area covered by the same species but unburned, runoff was lowered by 58%. The burned areas with M. tenacissima produced soil losses that were similar as those measured in bare soils, and, in steeper slopes, even higher. Erosion was instead much lower (-83%) in the sites with unburned vegetation. Overall, the control of erosion in these semi-arid lands is beneficial to reduce the possible hydrological effects downstream of these fire-prone areas. In this direction, the establishment of vegetation strips of M. tenacissima in large and steep drylands of bare soil left by fire may be suggested to land managers.
Estimating the diffusion in the deepest section of the Dome-C ice core using a new statistical method
Authors: Shaw Fyntan , Laepple Thomas , Kunz Torben , Gkinis Vasileios , Dahl-Jensen Dorthe
Published: March 2022

The diffusion of stable water isotopes in firn and ice is a complex process which can smooth the measured isotope profile and thus remove the high frequency variations. While for the firn this process is relatively well understood and can be accounted for, this is not the case in the deepest parts of the ice core, where additional processes are introduced due to the increased temperatures near bedrock. Combined with the extreme thinning the deep ice has experienced over hundreds of thousands of years, variations up to centennial or even millennial timescales can be heavily attenuated. Understanding how to best recover this signal in the deep ice is crucial to get a reliable record in deep ice cores such as the Beyond EPICA Oldest Ice Core that is currently being drilled.

In order to reconstruct the climate signal of this old ice, an accurate estimation of the diffusion length is necessary. Current estimation methods are mostly suitable for firn and shallow ice as they are assuming a rather stationary underlying climate signal. In this contribution, we present a method which approaches the issue without assuming the low frequency climate variability is negligible. Using this method on the high-resolution Dome-C isotope data (doi.pangaea.de/10.1594/PANGAEA.939445), we provide an improved estimate of the diffusion length of the Dome-C ice-core. Both the diffusion length estimate of the deep ice in Dome-C as well as the new method are useful for the interpretation of future deep ice coring projects such as Beyond EPICA Oldest Ice Core.
Radial anisotropy models and their uncertainties beneath Sri Lanka derived from joint inversion of surface wave dispersion and receiver functions using a Bayesian approach
Authors: Ke Kuan-Yu , Tilmann Frederik , Ryberg Trond , Dreiling Jennifer
Published: March 2022

Radial seismic anisotropy (RA) designates the difference between the speeds of vertically and horizontally polarized shear waves. RA in the crust can provide information on past tectonic events. Since the amplitude and impact of anisotropic are smaller than the variation of velocity, it is more difficult to distinguish whether radially anisotropic anomalies are driven by the structure or uncertainty. Hence, a lack of considering uncertainty and trade-off here may underestimate radial anisotropy and lead to divergent geodynamical interpretations. The hierarchical transdimensional Bayesian approach is able to provide uncertainty estimates taking fully into account the nonlinearity of the forward problem. Under the Bayesian framework, the mean and the variance of the ensemble containing a large set of models are interpreted as the reference solution and a measure of the model error respectively. 

In our study, we applied a two-step RA inversion of surface wave dispersion and receiver function based on a hierarchical transdimensional Bayesian Monte Carlo search with coupled uncertainty propagation to a temporary broadband array covering all of Sri Lanka. First, we constructed Rayleigh and Love wave phase velocity and errors maps at periods ranging from 0s to 20s. To remove outliers, data uncertainty distribution was expressed as a mixture of a Gaussian and uniform distribution. Next, we inverted local dispersion curves and receiver functions jointly to obtain 1D shear velocity and RA models. The method effectively quantifies the uncertainty of the final crustal shear wave velocity and RA model and shows robust results. The negative RA (Vsv > Vsh) anomalous with low uncertainty found in the mid-lower crust of Central Sri Lanka may show evidence that the charnockite inclusion is associated with the shear zones confined to the cores of some doubly-plunging synforms. In the east Highland Complex, the positive radial anisotropy (Vsh > Vsv) anomalous with low uncertainty may reveal the evidence for sub-horizontal shear zones along the thrust boundary.
Developing forecast information for institutional decision-makers
Authors: Budimir Mirianna , Sneddon Alison , Nelder Issy , Brown Sarah , Donovan Amy , Speight Linda
Published: March 2022

There remains a gap between the production of scientifically robust forecasts, and the translation of these forecasts into useful information such as daily “bulletins” for institutional decision-makers in early warning systems. There is significant published literature on best practice to communicate risk information, but very little to guide and provide advice on the process of how these bulletins have been, or should be, developed.

This presentation will discuss learning and share best practices of developing such early warning bulletins for institutional decision-makers, providing specific case study examples and drawing on wider experience from Practical Action and the Science for Humanitarian Emergencies And Resilience (SHEAR) programme.

The session will share lessons from two example case studies where bulletins were developed for national and district-level government agencies and humanitarian responders as part of the SHEAR programme: daily reports in response to Cyclones Idai and Kenneth in Mozambique, and prototype landslide forecast bulletins in Nilgiris and Darjeeling Districts of India.

There were significant similarities in the type of content included in the bulletins, such as the layout, choice of words, and use of visualisation that was consistent with published best practices. Both case studies experienced challenges dealing with uncertainty, complexity, and whether to include advice. There were also similarities in the processes and approaches taken to develop the bulletins. Both case studies took an iterative approach, developed feedback mechanisms, benefitted from experienced multi-disciplinary teams, emphasised the need for strong inter-relationships, and the importance and value of preparedness and protocols.

A major challenge was the difficulty of balancing science capabilities with user needs, which did not become significantly easier to deal with given more time availability. The findings indicate that whilst more research is needed into existing or best practice processes to develop content for forecast bulletins, there is an existing body of experiential and intuitive knowledge and learning that already exists but is not yet captured in an appropriate format that could be of significant interest and value to those developing and responsible for providing forecast information.

This presentation will share key learning from translating scientific forecasts into useful information, in particular on both the content and the process of developing forecast bulletins for decision-making.
Large-eddy Simulation of Surface Heterogeneity Induced Secondary Circulation with Ambient Winds
Authors: Zhang Lijie , Poll Stefan , Kollet Stefan
Published: March 2022

Land surface heterogeneity affects the distribution of energy from incoming solar radiation, and in conjunction with ambient winds, influences the convective atmospheric boundary layer development. In this study, experimental large-eddy simulations were carried out applying continuously-distributed soil moisture along a river corridor with idealized initial atmosphere conditions at a spatial scale on the order of kilometers. Simulations were performed with ambient wind ranging from 0 to 16 m/s and for different directions, which are cross-valley and parallel-valley. After decomposing the simulated winds into the ensemble-averaged wind, phase wind, and turbulence, the results show that soil moisture heterogeneity induces a well-organized secondary circulation structure with the horizontal mesoscale phase wind approaching some 2 m/s. The secondary circulation structure persists under the parallel-valley wind conditions independently of the wind speed, but is destroyed when the cross-valley wind is stronger than the horizontal mesoscale phase wind. We explored the relationship between the secondary circulation strength, expressed as the normalized maximum of the vertical phase wind variance, and dimensionless variables such as Bowen ratio and stability parameter (ratio of boundary layer depth and Obukhov length). With the mean of these dimensionless variables, we found a distinct relationship between the strength of the secondary circulations with respect to the ambient wind.
Introducing the "Global Deep Soil 2100" network
Authors: Schmidt Michael W. I. , Malhotra Avni ,   "Global Deep Soil 2100" network
Published: March 2022

"Global Deep Soil 2100" is a network for whole-ecosystem warming experiments. The aim of DeepSoil 2100 is to bring together researchers working on long-term soil experiments particularly focused on deep soil horizons (at least 1 m). The year '2100' was chosen because IPCC scenarios run until 2100. We welcome whole ecosystem warming manipulations, with or without other manipulations such as water and carbon dioxide concentrations, and studying responses of plants, soil biogeochemistry, ecology, etc.

Globally, there are less than a dozen whole-ecosystem warming experiments but not all researchers know about each other. To introduce experiments and involved scientists, we started video meetings at the end of 2020. This effort brought together experimentalists, modelers and data users into this "whole-ecosystem warming network", to share practical experience on field experiments, data reporting, discuss observations and results and explore synergies regarding tools, knowledge, and data sharing and interpretation. We hope that this network will serve as a basis for future data syntheses and coordinated sampling efforts.

View previous meeting recordings here:  https://tube.switch.ch/channels/ed725365
 
Further details and contact can be found on the webpage of the "International Soil Carbon Network"
https://iscn.fluxdata.org/network/partner-networks/deepsoil2100/

 
The effect of dynamic-unconfined loads on soil bearing capacity and hydraulic conductivity
Authors: Riveras Muñoz Nicolás , Salazar Osvaldo , Seitz Steffen , Scholten Thomas , Seguel Oscar
Published: March 2022

Bearing capacity (BC) can explain mechanical soil quality, but its alteration generally comes accompanied by changes in other soil functions. One way to determine BC is by compression tests on undisturbed soil samples, where increasing normal loads are applied at the surface of confined soil core cylinders. Nevertheless, in natural conditions soils are semi-confined, allowing the soil particles to move upward to release the applied forces. Furthermore, in agricultural soils, the loads are primarily dynamic, such as the traffic of machinery or cattle. In this study, we hypothesized that the application of dynamic loads on unconfined soils is more detrimental than static loads, reflected as a decrease in the functionality of two agricultural soils under conventional tillage management. For this purpose, static and dynamic pre-compression tests to determine BC were evaluated in 2 soils, 2 depth levels, and 2 levels of mechanical resistance (8 treatments in total), using semi-confined cylinders, complemented with measurements of saturated hydraulic conductivity (Ks) as an indicator of pore functionality before and after loading. When comparing the dynamic with the static test, it showed no changes in BCwhich was reflected in a homogenization under the studied conditions.. Nevertheless, an increase in Ks from 66 cm h-1 in the initial condition, to 186 cm h-1 in static condition, and 295 cm h-1 in the dynamic test could be shown. The increase in the dynamic test contradicted our initial assumption and could be attributed to cracking of the soils, boosted by the partial confinement of the samples, which allowed sideways movement of the soil against the loads creating zones of preferential flow.
A showcase pilot of seismic campaign using Distributed Acoustic Sensing solutions
Authors: Jestin Camille , Maisons Christophe , Chérubini Aurélien , Duboeuf Laure , Puech Jean-Claude
Published: March 2022

Distributed Acoustic Sensing (DAS) is a rapidly evolving technology that can turn a fibre optic cable into thousands of acoustic sensors. In this study, we propose to present a seismic survey conducted as a business showcase relying on a collaborative work supported by five partners: FEBUS Optics, RealTimeSeismic (RTS), Gallego Technic Geophysics (GTG), Petro LS and Well-SENSE. The project was carried out at a deep solution mining site developed for salt production, operated by KEMONE, and located nearby Montpellier (South of France).

The seismic campaign was based on two different cable deployments.

On the first hand, a Vertical Seismic Profile survey was conducted on borehole seismic measurements using two different fibre optic cables deployed in a 1800m deep vertical well. The first set of tests was performed along a Petro LS wireline cable including optical fibres. This deployment corresponds to a conventional wireline operation. The second set of data has been acquired along a FibreLine Intervention system (FLI) developed by WellSENSE. The deployment of the FLI system relies on the unspooling a bare optical fibre using a probe along a wellbore. This solution is single-use and sacrificial and can be left in the well at the end of the survey.

On another hand, a short 400m-surface 2D profile has been achieved along both a fibre optic cable and a set of STRYDE nodes deployed by GTG.

Fibre optic cables have been connected to FEBUS DAS interrogator to collect distributed acoustic measurements.  The seismic tests, performed in collaboration with GTG, have been achieved with basic “weight drops” (1T falling from 4m) for the checkshot surveys and with an "IVI Mark 4" 44,000-pound seismic vibrator for VSP shots at offset from wellhead reaching 865m. Acquired data have been analysed by RTS.

This work will describe the survey, present the results, and discuss the learnings in two ways:  the optimisation of acquisition setups and processing parameters to obtain the best exploitable results and seismic surveys perspectives and challenges using DAS technology.
Seasonal mixed layer heat budget in coastal waters off Angola
Authors: Körner Mareike , Brandt Peter , Dengler Marcus
Published: March 2022

The Angolan shelf system represents a highly productive ecosystem that exhibits pronounced seasonal variability. Productivity peaks in austral winter when seasonally prevailing upwelling favorable winds are weakest. Thus, other processes than local wind-driven upwelling contribute to the near-coastal cooling and nutrient supply during this season. Possible processes that lead to changes of the mixed-layer heat content does not only include local mechanism but also the passage of remotely forced coastally trapped waves. Understanding the driving mechanisms of changes in the mixed-layer heat content that may be locally or remotely forced is also vital for understanding of upward nutrient supply and biological productivity off Angola. Here, we investigate the seasonal mixed layer heat budget by analyzing atmospheric and oceanic causes for heat content variability. By using different satellite and in-situ data, we derive monthly estimates of surface heat fluxes, horizontal advection, diapycnal heat fluxes and local heat storage. The results show that the contribution of horizontal heat advection is small. When considering surface heat fluxes and horizontal heat advection only, the local mixed layer heat budget cannot be closed and the resulting residuum increases closer to the coast. Diapycnal heat fluxes at the base of the mixed layer and uncertainties of surface heat fluxes are suggested to explain the residuum. Our data suggests that the magnitude of diapycnal heat fluxes is controlled by stratification with stronger stratification reducing diapycnal heat fluxes. We conclude that local and remote impacts on stratification need to be examined in order to understand the mixed layer heat budget variability off Angola.
Is first-hand fieldwork still the best way into a career in marine sciences? Highlighting digital twinning of the oceans as a complementary and more inclusive pathway into a career in the marine sciences
Authors: McGregor Anna , Fisher Ben , Baker Chelsey A. , Robinson Carol , Damerell Gillian M. , Liszka Cecilia M. , Simmonds Natasha , Fielding Sophie , Muschitiello Pilvi
Published: March 2022

Participation in offshore fieldwork is a frequent pathway into a successful career in marine science due to the unique opportunities for practical skills development provided by such field experiences. However, the ability to participate in scientific research cruises can be hindered for those from certain backgrounds, such as physically disabled scientists with mobility limitations, those with caring responsibilities who cannot spend extended periods of time away from home, and early career researchers from minority groups who may perceive the limited confines of a research ship as a hostile or unwelcoming environment. 

Digital twinning is a new and rapidly developing area that describes how technologies and capabilities, including modelling, remote sensing, and linking shipboard equipment to shore visually in real-time, can be intertwined with traditional offshore operations to promote inclusivity and broaden the diversity of people involved in marine sciences. Here we will present preliminary results from our project that explores whether perceptions of fieldwork as a requirement for a career in marine science exist and whether jobs in marine science explicitly require these skills and experiences. Perceptions of fieldwork were evaluated through a series of questionnaires and semi-structured interviews with prospective marine scientists at undergraduate and PhD level. Additionally, we also conducted a systematic review of advertised vacancies in marine science to determine how perceived requirements for a career in marine science differed from the advertised required skills and experience.  Finally, we collated several case studies of effective use of digital twinning as a tool to enable those who cannot access offshore fieldwork to participate in scientific cruises. We aim to use these case studies to highlight the potential for digital twinning to act as a complimentary route into the field and act as an evidence base for continued investment in, and development of, new technologies to facilitate equitable and inclusive marine science.
Seismicity analysis of Southern Ghana II: Updated crustal velocity model and hypocentral parameters
Authors: Custódio Susana , Mohammadigheymasi Hamzeh , Tavakolizadeh Nasrin , Matias Luis , Silveira Graça
Published: March 2022

A small network of six broadband seismic sensors operated in southern Ghana between October 2012 and April 2014 (GHDSN). During this period, no seismicity was reported by the global data centers, however application of the Deep Learning algorithm EQTransformer resulted in the detection and subsequent location of 73 earthquakes. Preliminary constant crustal velocity models with  vp=5.55 km/s and vs=3.36 km/s have been utilized since 2002 to locate the local earthquakes in southern Ghana. Using this crude velocity model resulted in scattered seismicity, hinting into a likely inadequacy of these preliminary velocity parameters to represent the elastic properties of the area. In this study, we perform a joint-inversion for estimating an updated 1D crustal velocity model and the hypocentral parameters of the 73 recently detected local earthquakes. A grid search method is implemented and a 6-layer velocity model is defined, down to 45 km crustal depth. The space of velocity model parameters is searched by altering the upper depth of the layers (ud), P-wave velocity in each layer (vp), and the ratio of vp/vs. The optimized velocity model and hypocenteral parameters are evaluated by minimizing the RMS error function between the observed (533 picked phases consisting of 282 P and 251 S phases) and calculated arrival times. A two-step implementation is devised to increase the computational efficiency of the inversion process. Initially, the optimum  vp/vs is estimated by implementing a coarse grid search on vp and ud values. Then, incorporating the optimum vp/vs a fine grid search on vp and ud is applied.
The results yields layers with 1, 13, 8, 13 and 10 km thickness, with vp = 5.9, 6.1, 6.3, 6.5, 6.9 and 7.2 km/s, respectively. The updated velocities for the first and last layers are 6% and 26% percent higher than the previously reported constant velocity models. Furthermore, the updated vp/vs=1.70 is 0.03% higher than the corresponding value vp/vs=1.65 of the constant velocity model. The updated hypocentral locations of the 73 earthquakes with  2.5<ML<3.9 are concentrated on five major clusters. Two clusters are located on the AFZ, indicative of the active role of this structure in the seismicity of the region. Two other clusters, which have the highest rate of activity,  are positioned in the intersection between the AFZ and CBF. The last cluster consists of scattered earthquakes that coincide with mapped segments of the AFZ. Incorporating the updated velocity model for estimating the hypocentral parameters resulted in enhanced seismogenic source delineation in southern Ghana.  This research contributes to the FCT-funded projects SHAZAM (PTDC/CTA-GEO/31475/2017), RESTLESS (PTDC/CTA-GEF/6674/2020), SIGHT (PTDC/CTA-
GEF/30264/2017) and IDL (UIDB/50019/2020).