bluuebunny/crossref_metadata_2025 huggingface dataset:
Neutral Hydrogen in the Terrestrial Thermosphere and Exosphere: Ground-Based Observations
Authors: Mierkiewicz Edwin , Myers Brandon , Nossal Susan , Haffner L. Matthew
Published: February 2023

The exosphere is the interface between the Earth's neutral atmosphere and interplanetary space. Our understanding of this important interface, through observations of its mean state and its response to external forcing, will provide important constraints as we seek to develop a complete picture of our complicated space-atmosphere system. This talk will highlight the application of ground-based, high-throughput interference spectroscopy to the study of this important interface. Observations are made throughout the night; the base of the Earth's shadow is used as a first-order probe of the exosphere's altitude structure. Major areas of scientific focus include: (1) high resolution observations of the geocoronal hydrogen Balmer α line profile and its relation to excitation mechanisms, effective temperature, and exospheric physics; (2) retrieval of geocoronal hydrogen parameters such as the hydrogen column abundance [H], the hydrogen density profile H(z), and the photochemically initiated hydrogen flux φ(H); and (3) observations of the geocoronal hydrogen column emission intensity for the investigation of natural variability. Recent work from two unique spectrometers located in Wisconsin and Chile will be reported, with results highlighting each of these three areas of focus. Special emphasis will be placed on high spectral resolution line profile observations of the Balmer α emission line and the forward-model analysis of these data using the lyao_rt radiative transport code of Bishop [1999]. For example, an observed decrease in effective temperature with increasing shadow altitude is found to be a persistent feature for nights in which a wide range of shadow altitudes are sampled. This result will be interpreted in the context of the lyao_rt code. This work is supported by National Science Foundation award AGS-2050077. 
Structural investigations and U/Pb dating in the southern Paris basin do not record any Alpine deformation
Authors: Brown Stephen , Missenard Yves , Robion Philippe , Beccaletto Laurent , Allanic Cécile , Haurine Frédéric
Published: February 2023

Deformation of intraplate sedimentary basins essentially results from tectonic stresses that propagate from plate boundaries. Yet, the detailed characteristics of this far field propagation are often poorly constrained, especially in age. Recent developments of U/Pb dating of calcite precipitations in fault planes and veins hopefully greatly help to frame the schedule of deformation. This is the case for the Meso-Cenozoic Paris basin, liable to have recorded several Cenozoic events due to its location in the western Eurasian plate, like Pyrenean and Alpine collisions and Oligocene extension (ECRIS).Our study focusses on the southern Paris basin area, north of the Morvan massif, where Alpine deformations are expected. Field data reveal almost exclusively strike-slip deformations with variable σ1 direction. These results are about to be confirmed at the microscopic scale using Anisotropy of Magnetic Susceptibility and of P-Wave Velocity methods. Associated U-Pb dating of synkinematic calcites from Jurassic strata indicates distributed Eocene deformation and an absence of Oligocene or Miocene ages. Such ages suggest the record of Pyrenean and possibly ECRIS tectonic events. Strikingly, Alpine deformation and especially stress propagation leading to the growth of the Jura fold-and-thrust belt during Miocene does not imprint the studied area although the Alpine orogen is located closer than the Pyrenean belt.
Linear response for stochastic models of geophysical fluid dynamics with medium complexity
Authors: Broecker Jochen , Carigi Giulia , Kuna Tobias
Published: February 2023

An important question of climate science is the effect of a changing climate on the long term statistical properties of the atmosphere and ocean dynamics. Mathematically speaking, the question is whether and how statistical quantities of the dynamics (e.g. correlations, averages, variabilities etc) react to changes in the external forcing of the system.A (stochastic or deterministic) dynamical system is said to exhibit linear response if the statistical quantities describing the long term behaviour of the system depend differentiably on the relevant parameter (i.e. the forcing), and therefore a small change in the forcing will result in a small and proportional change of the statistical quantity. A methodology to establish response theory for a class of nonlinear stochastic partial differential equations has recently been provided in [1]. This contribution will discuss the ``ingredients'' necessary for this methodology on an intuitive level. In particular, the required mathematical properties of the system are related to their physical counterparts. The results are applied to stochastic single-layer and two-layer quasi-geostrophic models which are popular in the geosciences to study atmosphere and ocean dynamics.[1] G. Carigi, T. Kuna and J. Bröcker, Linear and fractional response for nonlinear dissipative SPDEs, arXiv, doi = 10.48550/ARXIV.2210.12129, 2022.
Contribution of multiple scattering to the distribution of Lyman alpha emission in comet comae
Authors: Suzuki Yudai , Yoshioka Kazuo , Masunaga Kei , Kawakita Hideyo , Shinnaka Yoshiharu , Murakami Go , Kimura Tomoki , Tsuchiya Fuminori , Yamazaki Atsushi , Yoshikawa Ichiro
Published: February 2023

Comets are important in understanding the material balance of current and past planets. Water production rates from comet nuclei have been evaluated using various instruments including a Japanese satellite, Hisaki. In case of UV observations, water production rates are generally evaluated through the comparison of the observations of the Lyman alpha radiance distribution and kinetic model of hydrogen atoms generated by photodissociation of water molecules. However, dynamics of hydrogen atoms in comae in the vicinity of nuclei has not been well understood especially for long period comets with large water production rates.In this study, we obtained the spatial distributions of Lyman alpha radiance through the analysis of spectroscopic data of long period comets such as C/2013 US_{10} (Catalina) observed by Hisaki. As a results, inclination of the Lyman alpha radiance was found to become flatter below the impact parameter of 5 × 10^{4} km. We attributed this variation of inclination to multiple scattering, and established a radiative transfer model considering multiple scattering of photons. Then we successfully reproduced the Lyman alpha radiance distributions in comae observed by Hisaki.According to calculations using this model, multiple scattering becomes effective in comae when the hydrogen column density exceeds approximately 5 × 10^{22} /km^{2}. Additionally, multiple scattering was found to cause the sunward/anti-sunward radiance asymmetry less than 3 %, and the apparent increase of D/H ratio around the nuclei by a factor of more than 10.Using these results, the feasibility of detecting deuterium and evaluating the D/H ratio via Hydrogen Imager (HI) onboard the Comet Interceptor spacecraft was discussed. It was found that deuterium could be detected with a sufficient S/N ratio and that the D/H ratio could be evaluated with relative error less than 60 % using the model. The largest error factor in D/H ratio calculation is the dependence of the results of radiative transfer model on hydrogen temperature. Constraint on observations by HI or calculation by models such as DSMC will enable the calculation of the D/H ratio with higher accuracy.
Measurement of the rate of change of the electron heat flux due to the whistler instability with Solar Orbiter observations
Authors: Coburn Jesse , Verscharen Daniel , Owen Christopher , Horbury Timothy , Maksimovic Milan , Chen Christopher , Guo Fan , Fu Xiangrong
Published: February 2023

Non-Maxwellian features of the coronal electron population are important for some models of solar wind acceleration processes. Remnants of these features are detectable in spacecraft observations, in particular in the form of field-aligned beams (strahl) and anti-sunward deficits in the electron distribution function. These features are shaped by expansion, collisions, and kinetic effects. Therefore, determining how these processes alter the distribution is important for our understanding of how the solar wind accelerates and evolves. The strahl and deficit contribute to the overall electron heat flux. If the heat flux crosses the threshold for instabilities, the plasma will generate waves which in turn reduce the heat flux via pitch-angle scattering of electrons out of the strahl and/or into the deficit. The work presented here examines an interval observed by Solar Orbiter during which short bandwidth whistler waves are observed by the Radio and Plasma Waves instrument. We apply a method to measure the pitch-angle gradient to high cadence pitch angle distribution (PAD) functions measured by the Electrostatic Analyser System to quantify the rate of change of heat flux from quasilinear theory. The primary part of the measurement technique is based on low-pass filtering of the PAD function with a Hermite-Laguerre transform providing a measurement of the pitch-angle gradient. We compare our quantification of the rate of change of the heat flux with other timescales and processes relevant in the solar wind. We show the potential of our technique to further our understanding of the role of wave-particle interactions in the evolution of the solar wind electrons.
The First Observations of Deimos from the Emirates Mars Mission (EMM) Flybys
Authors: Edwards Christopher , Osterloo Mikki , Fisher Charles , Jeppesen Chris , Smith Nathan , Holsclaw Greg , Wolff Michael , Jonees Andrew , Knavel Justin , Pilinski Emily , Kubitschek Daniel , Teil Thibaud , Deighan Justin , Al Matroushi Hessa , Parker Jeff , Christensen Philip , Anwar Saadat , Reed Heather , Withnell Pete , Sharaf Omran
Published: February 2023

The origins of the martian moons Phobos and Deimos remain enigmatic. Over the past decades a range of spacecraft have observed Phobos and Deimos in order to constrain their origin and evolutionary history, with proposals for their origins ranging from captured asteroids, to coalesced material from a giant impact on Mars. However, given the orbits these spacecraft and the orbits of Phobos and Deimos, Phobos has garnered the majority of the attention. Now thanks to the unique orbit of the Emirates Mars Mission (EMM) Hope spacecraft and a minor correction to its nominal science orbit, EMM has a unique opportunity to examine Deimos in great detail while fully retaining the originally designed mission to capture the variability in the martian atmosphere and exosphere.Following a minor orbital adjustment maneuver campaign beginning in August 2022, EMM will encounter Deimos multiple times, progressively observing the martian moon at lower and lower distances beginning in early 2023. These flybys culminate in the closest approach of ~150 km, observing the mostly illuminated, far side of Deimos. All three EMM instruments, the Emirates eXploration Imager (EXI), the Emirates Mars Infrared Spectrometer (EMIRS), and the Emirates Ultraviolet Spectrometer (EMUS) have observation sequences tailored to these flybys, collecting the highest resolution multispectral visible imaging data, thermal infrared surface temperatures and emission spectra, and ultraviolet spectra.  When combined these instrument observations will provide key insights into the composition, morphology, and surface physical properties of the least studied martian moon, Deimos.
An Efficient, Time-Dependent High Speed Stream Model and Application to Solar Wind Forecasts
Authors: Kay Christina , Nieves-Chinchilla Teresa , Hofmeiseter Stefan , Palmerio Erika
Published: February 2023

Predicting space weather effects of the solar wind requires knowing the location and properties of any embedded high speed streams (HSSs) or stream interactions regions that form as the fast solar wind catches up to slow preceding wind. Additionally, this information is critical for understanding how a coronal mass ejection (CME) interacts with the solar wind during its propagation. We present the Mostly Empirical Operation Wind with a High Speed Stream (MEOW-HiSS) model, which runs nearly instantaneously. This model is derived from MHD simulations of an idealized HSS emanating from a circular coronal hole (CH). We split the MHD HSS radial profiles into small regions well-described by simple functions (e.g. flat, linear, exponential, sinusoidal) that can be constrained using the MHD values. We then determine how the region boundaries and the constraining values change with CH area and the distance of the HSS front. MEOW-HiSS requires the CH area and front distance and produces the corresponding radial profile with an error less than 10\% for most parameters. MEOW-HiSS produces profiles at subsequent times with almost no loss in accuracy. We also compare MEOW-HiSS results to four HSS observed in situ at 1 au. We present a method for determining MEOW-HiSS inputs from EUV images and use these values to hindcast the observed cases. We find average accuracies of 2.8 cm^-3 in the number density, 56.7 km/s in the radial velocity, 2.2 nT in the absolute radial magnetic field, 1.6 nT in the absolute longitudinal magnetic field, and 7x10^4 K in the temperature.
A novel approach to investigate Cirrus cloud formation
Authors: Lüttmer Tim , Spichtinger Peter
Published: February 2023

Warm conveyor belts (WCB) lead to formation of horizontally wide spread Cirrus clouds in the upper troposphere. However, the contribution of different ice formation processes and the resulting micro- and macrophysical properties of the Cirrus ,e.g., their radiative effects are still poorly understood. We want to especially address the research question of in-situ vs. liquid origin ice formation.Common microphysics bulk schemes only consider a single ice class which includes sources from multiple formation mechanisms. We developed and implemented a two-moment microphysics scheme in the atmosphere model ICON that distinguishes between different ice modes of origin including homogeneous nucleation, deposition freezing, immersion freezing, homogeneous freezing of water droplets and secondary ice production from rime splintering, frozen droplet shattering and collisional break-up, respectively. Each ice mode is described by its own size distribution, prognostic moments and unique formation mechanism while still interacting with all other ice modes and microphysical classes like cloud droplets, rain and rimed cloud particles.Using this novel microphysics scheme we can determine the contribution of the various ice formation mechanisms to the total ice content. For the first time this allows us to directly investigate the competition of in-situ and liquid origin Cirrus as well as homogeneous and heterogeneous ice nucleation with regards to environmental conditions and choice of microphysical parameterisations.We performed an ensemble of simulations for selected WCB cases to cover a range of microphysical properties and compared the results of our liquid origin vs in-situ analysis with other Cirrus categorization algorithms.
Addressing cell size selection in geodiversity quantitative assessment procedures
Authors: Lopes Catarina , Teixeira Zara , Pereira Paulo
Published: February 2023

Within geodiversity assessment methods, the grid system is the most used approach to calculate a geodiversity index. Chosen for its simplicity and adjustment aptitude, it implies a fundamental and determinant decision, namely the selection of the cell size. This should comply with the inherent properties of the input datasets, being as well a function of the main goals of the analysis. This problematic has been studied by several authors, either by discussing and presenting analytical procedures, or by testing the effect of distinct cell sizes on their (modelling) analysis.Being a key issue within geodiversity assessment methodologies, in this work an empirical methodology is presented to select the most appropriate cell size to assess the geodiversity of Portugal mainland. A direct quantitative method based on geodiversity indices was applied, using richness, and Simpsons’ and Shannon’s diversity and equity indices to geology (1:1000 000) and geomorphology (1:500 000) datasets of mainland Portugal, in a hexagonal analytical grid, through eight cell dimensions (1km, 2km, 5km, 10km, 15km, 20km, 25km and 30km). Several descriptive statistical parameters were analysed along the eight cell dimensions, for each map, with particular emphasis for dispersion statistical measures, namely quartile coefficient of dispersion, coefficient of variation, and skewness coefficient, range, Min, Max and IQR. The effect of cell size on the final maps of lithological and geomorphological diversity was also analysed, using the conventional representation of five classes (very high, high, medium, low and very low) based on the Jenks classification, by evaluating the area occupied per each class along the distinct cell sizes. The results from the analysis indicate that skewness coefficient, quartile coefficient of dispersion and coefficient of variation could be used as indicators of optimal cell size. All the performed analysis indicated the 5-10km dimension as the optimal cell size for the diversity and richness analysis, also considering the differences between both datasets, namely distinct scale, distinct polygon distribution area, distinct number of total features (categories). In general, the evenness and diversity indices seem to be more appropriated to be used as cell size indicators when applying statistic parameters, while richness seems to provide more clear results while using final maps and correspondent graphics that synthetize the area distribution per class. The empirical procedure here presented seems to be applicable to all type of scales and datasets.
Monitoring pore-pressure from Vp/Vs ratio around the Costa Molina 2 wastewater disposal well in southern Italy
Authors: De Landro Grazia , Stabile Tony Alfredo , Muzellec Titouan , Serlenga Vincenzo , Zollo Aldo
Published: February 2023

Monitoring conditions of the medium embedding the reservoir is strictly required for the hazard assessment in exploited areas.Fluid injection/extraction operations cause a pressure perturbation into the volume hosting the reservoir which, in turn, may trigger new failures and induce changes in the elastic properties of rocks. Therefore, technologies are needed to reconstruct pore-pressure evolution around injection wells.To test how the conditions of the reservoir can be monitored noninvasively by using induced micro-seismicity, here we show a rock physics approach aimed to reconstruct the pore-pressure temporal evolution from the changes in Vp/Vs ratio.  We applied this strategy to the volume affected by the wastewater disposal activity of the Costa Molina 2 injection well, located in the High Agri Valley (Southern Italy) and belongs to the Val d’Agri oilfield, the largest productive onshore oil field in West Europe that produces hydrocarbons (oil and gas) from a fractured carbonate reservoir. We analyzed an enhanced seismic catalogue of the induced micro-seismicity, occurred between 2016 and 2018, that consists of 196 located earthquakes in the magnitude range − 1.2 ≤ Ml ≤ 1.2. For the same period, both seismicity recordings and fluid-injection data are available.For the evaluation of Vp/Vs ratio with the Wadati formula, the accurate measure of arrival time is critical, especially in case of micro-events. So, we first refined with high precision the first P- and S-wave arrival times by using waveform cross-correlation and hierarchical clustering and selected the events with a high DD location quality; then, we calculated the Vp/Vs ratio for each source-station couple and averaged the ratio values for all the events at the stations nearest to the well (INS1, INS2, INS3) to reconstruct the elastic properties temporal evolution in the source region around the well. We found that the Vp/Vs ratio temporal evolution well correlates with injection operational parameters (i.e. injected volumes and injection pressures). With a rock physics model, by using the Pride approach of the Biot theory, we reconstruct the pore-pressure temporal variation starting with the Vp/Vs as known parameters, thus demonstrating the value of seismic velocity monitoring as a tool to complement a monitoring system.
Investigation of fault behaviour during shear process for weak and strong materials using 3D printing technologies
Authors: Conin Marianne , AbiAad Emilio , Deck Olivier , Jaber Jana
Published: February 2023

Morphology of rock joints (faults, fractures) has been recognized as the key factor controlling their mechanical behaviour, including the pre-peak and post peak phases as well as dilatancy. It also appears playing a significant role in two mechanical behaviours that have been observed on natural fracture during shearing: (i) joint dilation, or (ii) joint closure in association with asperities crushing, and rock matrix plastic deformation. We examine how (i & ii) occur in the joint, discussing their relationship with normal stress, joint morphology and intact matrix mechanical properties. To do this, two innovative methodologies based on 3DP technologies using a sand and phenolic binder on one side and a polymer (PA12) and binder jetting technology on the other one are applied to built fractures in a weak matrix, and in a strong matrix respectively. Joint surface roughness are built as fractal property with a self–affine replication, in accordance with natural observations. Results of direct shear tests under constant normal stress reveal that the mechanical behavior of the joints is first controlled by the mechanical parameters of the material (UCS/σn ratio), then by the joint geometry. In the case where the UCS/σn ratio is high (>40) corresponding to a strong material compares to the mechanical solicitation, no significant damage is notice on the joint and the maximal dilation angle is controlled by the steepest angles of the shorter wavelength asperities, which may only represent a small percentage of the surface roughness. In a the case of a weak material the joint behaviour is more complex, and is controlled by a specific range of asperities sizes. Three behaviours were observed depending on the applied normal stress: (i) at low normal stress the larger wavelengths asperities cause dilation since they are not sheared off; (ii) at normal stress over 40% of the UCS value, tensile and/or slip cracks were observed around those asperities, leading to their crushing and beheading; (iii) at normal intermediate stress, the two mechanisms were conjointly observed. In the second case (ii) joint closure is observed and the permeability increases in the surrounding matrix. Those results implies that the UCS/σn ratio plays an key role in fault shear behaviour, off-fault damage propagation and fluid circulation.
Time-space variations in the East African Rift magmatism: the role of different mantle domains
Authors: Braschi Eleonora , Bragagni Alessandro , Orlando Andrea , Guarnieri Luisa , Corti Giacomo , Tommasini Simone
Published: February 2023

The East African Rift System (EARS) is the classic example of an active continental rift where extensional tectonics and lithospheric thinning have been closely associated to the generation of large volumes of magmas and represents the environment with the largest range of erupted magma types all over the world. The geochemical signature of erupted magmas testifies the involvement of different mantle domains and depths (i.e., subcontinental lithosphere, asthenosphere and deeper mantle sources). The aim of this contribution is to investigate the variable involvement of different mantle domains in the genesis of the EARS magmas through space and time, considering not only the geochemical signature of erupted magmas but also the geochemical message of mantle xenoliths. The main goal is to provide a large-scale view of the common process driving the origin of magmas in the EARS beyond the local peculiarities linked to specific settings. We screened an exhaustive geochemical database of basalts and mantle xenoliths from the EARS, together with original trace elements and Sr-Nd isotope data of new samples collected from the Main Ethiopian Rift and Turkana depression, subdivided according to spatial and temporal criteria. From a spatial point of view, the samples were ascribed to five groups (Afar, Ethiopia, Turkana, Eastern Branch, and Western Branch) and from a temporal point of view, the magmatic activity of the EARS was subdivided into three main temporal intervals (45-25 Ma, 25-10 Ma and 10-0 Ma). The geochemical and radiogenic isotope (Sr, Nd, Pb) signature of the selected basalts denotes the variable contributions of a mantle plume, a more depleted asthenospheric mantle (DMM), and different SubContinental Lithospheric Mantle (SCLM) domains, depending on their temporal and spatial distribution. The geochemistry of the selected basalts shows a marked correspondence with the compositional heterogeneity of mantle xenoliths, whose isotopic systematics (Sm-Nd, Re-Os) indicates the formation of the local SCLM in the Archean and during the Pan-African orogeny. Both SCLM domains contributed significantly to magma genesis in the Western Branch (whose signature points towards a contribution of the Pan-African lithosphere) and Eastern Branch (which is also affected by Archean SCLM domains) magmas. We outline that the contribution of the SCLM generally increases with time, possibly related to an increase of the geothermal gradient in response to the arrival and flattening of the plume head at the base of the lithosphere and later extension, thinning and shallower melting. Our interpretation supports a pivotal role of the different SCLM domains in magma genesis that is able to fully explain the large compositional heterogeneity of the EARS basalts and represents a reasonable alternative to the putative presence of multiple mantle plumes or a heterogeneous mantle upwelling.
An assessment of the performance of bias correction techniques for surface ozone burdens simulated by global chemistry-climate models
Authors: Stähle Christoph , Rieder Harald E. , Fiore Arlene M. , Checa-Garcia Ramiro
Published: February 2023

Despite continuous improvement during recent decades, state of the art global chemistry-climate models (CCMs) are still showing biases compared to observational data, illustrating remaining difficulties and challenges in the simulation of atmospheric processes governing ozone production and decay. Therefore, CCM output is frequently bias-corrected in studies seeking to explore changing air quality burdens and associated impacts on human health (e.g., Rieder et al., 2018). Here we assess the strengths and limitations of different bias correction techniques for CCM simulations with focus on maximum daily 8-hour average surface ozone. Ozone fields are chosen as ozone is known as regional pollutant and thus shows smaller spatial heterogeneity in its burden than e.g. particulate matter. Within our comparison a set of different innovative, as well as, common bias correction techniques are applied to output of selected global coupled CCMs contributing hindcast simulations to the Coupled Model Intercomparison Project Phase 6 (CMIP6). For bias correction and evaluation, we utilize gridded observational data for the European and US domains according to Schnell et al. [2014]. The statistical bias-correction techniques applied and compared are quantile mapping, delta-function, relative and mean bias correction. As surface ozone pollution is commonly associated with a strong seasonal cycle, the adjustment techniques are applied to model data on monthly basis, and skill scores for individual bias correction techniques are compared across individual CMIP6 models for both seasonal and annual timescales over the period 1995-2014. Our results highlight large differences among individual bias correction techniques and advocate for the use of more complex correction strategies involving corrections across the spatio-temporal distribution of the ozone field.References:Rieder, H.E., Fiore A.M., Clifton, O.E., Correa, G., Horowitz, L.W., Naik, V.: Combining model projections with site-level observations to estimate changes in distributions and seasonality of ozone in surface air over the U.S.A., Atmos. Env., 193, 302-315, https://doi.org/10.1016/j.atmosenv.2018.07.042, 2018.Schnell, J. L., Holmes, C. D., Jangam, A., and Prather, M. J.: Skill in forecasting extreme ozone pollution episodes with a global atmospheric chemistry model, Atmos. Chem. Phys., 14, 7721–7739, https://doi.org/10.5194/acp-14-7721-2014, 2014.
Post-wildfire monitoring for hazard mitigation in Alpine area
Authors: Corti Monica , Corti Laura , Abbate Andrea , Papini Monica , Longoni Laura
Published: February 2023

In a climate change scenario, natural disasters and their consequences are expected to increase. In particular, it is proven that the raise of global temperature will drive a higher occurrence of wildfires, leading to a wide range of problems in the mountain areas, such as slope instabilities. As confirmed by many authors, in addition to the disruption of vegetation, wildfires have indeed severe effects over the natural slopes, linked to the hydrological changes provoked by burning, which may cause further economic losses and casualties.The risen probability of flash flooding and debris flows after wildfires is recognized to depend on an alteration of the soil hydrological properties, and in particular of the soil infiltration capacity. Many studies in literature focused on the trends of soil infiltration recovery after fire, but none of them regards Alpine case studies and only a few are European, even if wildfire phenomenon is relatively common nowadays in the Alps. Furthermore, rainfall thresholds for possible landslide triggering have not been defined for wildfire-affected areas yet.This work investigates the impact of a wildfire occurred in 2019 in the Southern Alps, starting from the data collected during three years of monitoring activity at different spatial scales and after laboratory rainfall simulations. The investigation of the burnt area was conducted both remotely, by the analysis of Copernicus Sentinel-2 imagery, and throughout field surveys, by performing falling-head infiltration tests. The monitoring activity was distributed over three different sub-areas, taking into account the different fire severity (burnt or unburned sub-area) and the original vegetation type (pine woods or grassland). Moreover, soil samples were collected inside those sub-areas for further laboratory permeability tests and rainfall simulations.Results were used to retrieve recovery trends for the calibration of a simple 1D hydrogeological model.In particular, the remote sensing analysis helped to evaluate a recovery time of seven years of the site to pre-fire conditions. On the other hand, field monitoring suggested the recovery to depend mostly on the restoration of the canopy protection, as preventing factor for direct responses to rainfall and soil erosion.
Observing and Modeling the variability of DWLs during the summer Monsoon in the Northern Indian Ocean
Authors: Kerhalkar Siddhant , Tandon Amit , Schlosser Tamara , Farrar J.Thomas , Lucas Andrew , Johnson Leah , Hormann Verena , Centurioni Luca
Published: February 2023

Diurnal Warm Layers (DWLs) play an important role in coupling the atmosphere and the ocean, but their observations in the freshwater dominated Northern Indian Ocean in summer Monsoons are rare. This study focuses on the following aspects of DWLs observed during a 5-day suppressed atmospheric convection phase of the southwest monsoon season in 2019: (i) DWL observations using innovative drifting flux profilers to simultaneously measure high resolution shear and stratification as well as the surface meteorological forcing variables to compute air-sea fluxes (ii) Observed spatial gradients of SST over 1-100 km scales and (iii) Modeling using the popular one-dimensional models increasing in complexity. These observations show regions of marginal shear instability at the DWL base in agreement with previous studies in the tropical Pacific. The commonly used constant stratification assumption within the DWL (e.g. Fairall et al. 1996) breaks down in scenarios with weaker winds and salinity-driven stratification. The vertical structure of DWLs is therefore explored using k-e turbulence closure scheme in General Ocean Turbulence Model (GOTM) framework. Insights from model-observation comparisons show that for days with similar wind speeds, the DWL response can vary based on whether warm water or freshwater advection plays a role. Notably, warm water advection leads to deeper DWLs, whereas the freshwater advection traps the DWL to shallower depths. Further, spatial differences of O(1 C) in diurnal cycles of SST are observed over O (1-100 km), showing remarkable lateral inhomogeneity in the evolution of DWLs. 
Into uncharted territories – subsidence along Africa’s Gulf of Guinea coast?
Authors: Teatini Pietro , Minderhoud Philip , Hauser Leon , Bonì Roberta , Avornyo Selasi Yao , Ikuemonisan Femi Emmanel , Ohenhen Leonard , Wade Cheikh Tidiane , Zoccarato Claudia , Addo Kwasi Appeaning , Ozebo Vitalis Chidi , Shirzaei Manoochehr , Ngom Fatou Diop , Woillez Marie-Noëlle
Published: February 2023

The coastline of the African Gulf of Guinea hosts large river deltas, coastal wetlands and mangrove ecosystems. It is in places densely populated, with many capital megacities with millions of inhabitants such as Lagos, Abidjan and Accra situated at the coast. And population projections for these cities suggest a continued staggering increase in the coming decades. Also, many of the economic activities are located along the coastline. For example, Nigerian coastal areas are home to 85% of the nation industry and to more than 100 million people. On the other hand, the coastland retains pristine transitional environments formed during the Holocene, well recognized for the great biological richness and the high level of endemism. These pressures and foreseen growth make these lowly elevated coastal areas particularly vulnerable to relative sea-level rise (SLR).Regional or local impact studies of climate-change induced global sea-level rise are scarce and, when available, do not account for vertical land motion, i.e. land subsidence. Coastal land subsidence is critically under-quantified at global scale and the Gulf of Guinea region is no exception to this. Meanwhile, examples elsewhere in the World show coastal economic development and population growth can accelerate land subsidence to rates that are magnitudes larger than global SLR. With the fast-paced developments taking place along the Gulf of Guinea’s coastline, land subsidence poses an unknown but potentially large hazard to this region.Here, we present the first findings in our work to assess coastal subsidence in this fast-changing region of the World, through regional and local case studies and satellite assessments. By building on the recent advancements in global elevation data, we aim to update coastal elevation estimates and identify low lying hotspots with high vulnerability to relative SLR. Ultimately, we aim to project coastal elevation change for this important region and, in case of human-induced land subsidence, show how much relative SLR can potentially be avoided by changing to sustainable use of natural resources. Hence, we may be able to alter the fate of deltas, wetlands and coastal cities by quantifying and addressing land subsidence as early as in this fast growing region of the world.
Impact of calibration metric selection and spatial heterogeneity in soil parameters on the realism of distributed hydrological models
Authors: Mendoza Pablo A. , Vásquez Nicolás , Cortés-Salazar Nicolás , Mizukami Naoki , Vargas Ximena
Published: February 2023

Distributed hydrological models are useful tools to explicitly simulate the spatial heterogeneity of water and energy fluxes and storages. Nevertheless, their parameters are typically calibrated using streamflow-based objective functions that integrate information on the spatial variability of physical processes into a single metric. Additionally, these models contain several soil parameters that can be distributed in space, affecting the spatial representation of hydrological variables. Here, we examine the implications of streamflow-based calibration metric selection and spatial heterogeneity in soil parameters on the realism of model simulations, with emphasis on spatial patterns. To this end, we conduct several calibration experiments in six pilot basins with different hydrological regimes (two snowmelt-driven, two mixed-regime, and two rainfall-driven basins), in central-southern Chile, using the Variable Infiltration Capacity (VIC) model coupled with the mizuRoute routing model. In each experiment we assess, for a given calibration objective function, the effects of distributing individual soil parameters using a spatial regularization strategy based on principal component analysis of physiographic and soil characteristics (elevation, slope, clay content, sand content and bulk density), defining the case of spatially constant soil parameters as the benchmark (i.e, only meteorological forcing data and vegetation attributes are spatially distributed). To evaluate simulated spatial patterns, we use satellite remote sensing data of soil moisture from the ESA-CCI product, and fractional snow-covered area, actual evapotranspiration (ET), and land surface temperature from MODIS products. The results show that similar streamflow performance metrics can be achieved with different combinations of regularized soil parameter and calibration metric; however, the simulated spatial patterns can be considerably different, without clear connections with the hydrological regime. Further, a streamflow-based calibration is insufficient to represent the seasonality of other variables, especially in water-limited catchments, where important shifts (e.g., up to five months) in peak ET can be obtained compared to the reference product.
Proposal of a simple procedure to derive a more FAIR open data archive than a spreadsheet or a set of CSV files
Authors: Giadrossich Filippo , Murgia Ilenia , Scotti Roberto
Published: February 2023

NuoroForestrySchool (a study center of the Department of Agriculture, University of Sassari, Italy) has developed and published a ‘data documentation procedure’ (link to NFS-DDP) enabling the improvement of the dataset FAIRness that any data collector wishes to share as open data. Datasets are frequently shared as spreadsheet files. While this tool is very handy in data preparation and preliminary analysis, its structure and composition are not very effective for storing and sharing consolidated data, unless data structures are extremely simple. NFS-DDP takes in input a spreadsheet in which data are organized as relational tables, one per sheet, while four additional sheets contain metadata standardized according to the Dublin Core specifications. The procedure outputs an SQLite relational database (including data and metadata) and a pdf-file documenting the database structure and contents. A first example application of the proposed procedure was shared by Giadrossich et al. (2022) on the PANGEA repository, concerning experimental data of erosion in forest soil measured during artificial rainfall. The zip-archive that can be downloaded contains the experiment data and metadata processed by NFS-DDP. At the following link is available a test document where basic statistics are computed to show how NFS-DDProcedure facilitates the understanding and correct processing of the shared dataset. The NFS-DataDocumentationProcedure provides a simple solution for organizing and archiving data aiming to i) achieve a more FAIR archive, ii) exploit data consistency and comprehensibility of semantic connections in the relational database, ii) produce a report documenting the collection and organization of data, providing an effective and concise overview of the whole with all details at hand.Giadrossich, F., Murgia, I., Scotti, R. (2022). Experiment of water runoff and soil erosion with and without forest canopy coverage under intense artificial rainfall. PANGAEA. DOI:10.1594/PANGAEA.94345
Significance of ophiolitic mélanges and chaotic rock units in the evolution of subduction complexes and orogenic belts
Authors: Festa Andrea , Barbero Edoardo , Dilek Yildirim , Remitti Francesca , Ogata Kei , Pini Gian Andrea
Published: February 2023

Most ophiolitic mélanges and chaotic rock units in exhumed subduction zone complexes and orogenic belts are commonly interpreted as the products of tectonic processes (e.g., underplating and return flow) acting at intermediate to great depths (depth > 10–15 km, T > 250 °C) at convergent margins. Conversely, observations from modern and ancient, non- to poorly metamorphosed subduction–accretion complexes (recognized as mélanges and chaotic rock units) around the world show that these rock associations: (1) likely formed at shallow structural levels first, and (2) were later subducted and became tectonically reworked. As such, they mainly consist of broken formations (> 21.5%), and sedimentary (c. 20%), polygenetic (> 13.7%) and/or diapiric (c. 6.7%) mélanges. Tectonic mélanges are limited to <3.0% (in surface distribution), suggesting that tectonic processes do not make efficient mixing mechanisms at shallow structural levels. Subduction of structural inheritances (e.g., ocean-continent transition zones, and lithological and structural heterogeneities in ocean plate stratigraphy – OPS – assemblages) plays a more significant role in forming mélanges and chaotic rock units at shallow depths; it can also control the origin and location of plate interface and the dynamics of the wedge front (i.e., tectonic accretion vs. erosion). However, not all chaotic rock units that formed at shallow structural levels may become subducted; but, if subducted, their fate might be different depending on whether they become part of the plate interface or if they become part of the lower plate. Our global field observations, suggesting that most mélanges and chaotic rock units form at shallow depths, have significant implications for the tectonic evolution of subduction zone complexes and orogenic belts.
Tracking Convective Storms and their Environments with the tobac Tracking Package
Authors: Freeman Sean , Schulte Rick , Leung Gabrielle , van den Heever Sue
Published: February 2023

Understanding how convective storms respond to changes in their environment on a local scale is critical to begin to elucidate how Earth’s changing climate will affect storms globally. There is now a vast amount of storm-scale observational data, including from geostationary and low-earth orbiting satellites and ground-based observing systems. However, employing these datasets to build comprehensive databases of convective storms and the local environments that form them requires new analysis methodologies. Here, in preparation for the NASA INCUS satellite mission, we have used the tobac tracking package to identify, track and analyze storms and their environments with these big datasets. Using tobac to track storms with geostationary satellite and ground-based radar data, we have built a comprehensive, months-long database of convective storms over their entire lifetime. For each individual convective storm, the database contains their formation environments (including convective available potential energy, wind shear, etc.), evolution over time, and, where applicable, additional data, such as those from low earth orbiting satellites. In this presentation, we will employ this vast database of clouds and storms to quantify the relationship, on a storm scale, between thermodynamic and dynamic environments and storm properties, including lifetime, growth rate, and ice and liquid water paths. 
Stress sensitivity of gypsum dehydration kinetics at constant uniaxial stress under dry conditions
Authors: Schrank Christoph , Blach Tomasz , Ji Yeping , Vu Phung , Wang Xiaodong , Jones Michael , Kirby Nigel , Seibt Susanne , Regenauer-Lieb Klaus
Published: February 2023

We recently showed that the dehydration of alabaster, natural gypsum rock with randomly oriented grains, can be accelerated by a factor of two through the application of an elastic differential pre-stress of ~ 5 MPa applied via a uniaxial constant-displacement boundary condition (https://doi.org/10.1038/s43246-021-00156-9). Here, we present a novel series of gypsum dehydration experiments using a new in-situ experimental cell monitored with fast synchrotron transmission small- and wide-angle X-ray scattering (SAXS/WAXS) to investigate if an acceleration of the kinetics also occurs at constant uniaxial stress. Prior to stressing and heating, the loaded sample chamber was flushed with nitrogen to remove atmospheric moisture and finally locked, filled with the nitrogen atmosphere pressurised to 1 bar. Six increasing uniaxial stresses in the interval [0;10] MPa were studied at a dehydration temperature of 142˚C. A strongly nonlinear acceleration of dehydration rate is observed over the studied stress interval. At 10 MPa, the reductions of induction and characteristic time amount to ~60% and ~50%, respectively. 2D SAXS patterns generally evolve from isotropic to highly anisotropic shapes, indicating preferential growth of nano-scatterers. Post-mortem scanning-electron imaging reveals that the phase transformation occurs via pseudomorph replacement. These results are largely consistent with our previous experiments and support the notion that tectonic stresses affect mineral transformation kinetics.
A Case Study of the Highest Ever Altitude of In Situ Observations of Convective Hydration of the Stratosphere during the DCOTSS Field Campaign
Authors: Homeyer Cameron , Smith Jessica , Bui Thaopaul , Dean-Day Jonathan , Hanisco Thomas , Hannun Reem , St Clair Jason , Bedka Kristopher
Published: February 2023

On 24 June 2022, remnant outflow from a tornadic supercell storm that occurred in northern Kansas on the evening of 23 June 2022 was observed by the high-altitude NASA ER-2 aircraft during the Dynamics and Chemistry of the Summer Stratosphere (DCOTSS) field campaign. Namely, preliminary analysis indicates that stratospheric water vapor enhancements were observed at altitudes up to approximately 19.25 km (~1 km higher than any prior documented event), approximately 460 K potential temperature (~30 K higher than any prior documented event), and ozone mixing ratios of more than 1400 ppbv (more than double any prior documented event). The responsible storm was one of the most extreme events observed annually in the United States, within no more than 10 per year such high-reaching storms based on ground-based radar climatology. Here, we review the event using high-resolution ground-based radar volumes and satellite imagery and show that it reached altitudes exceeding 19 km for at least an hour. Linkages to the Kansas storm will be demonstrated via trajectory analyses initialized in the volumes impacted by the storm (as determined from radar and satellite observations). Broader evaluation of stratospheric composition impacts resulting from this event will also be presented. 