bluuebunny/crossref_metadata_2025 huggingface dataset:
On a few characteristics of geophysical turbulent flows 
Authors: Pouquet Annick
Published: March 2024

Our understanding of turbulence has progressed significantly through combining experiments, observations, theoretical developments, direct numerical simulations and modeling. I will discuss briefly three problems (among many) for which our perception has changed: (i) the derivation of a multitude of exact laws stemming from conservation properties, e.g. in fluid, magnetohydrodynamics (MHD) and Hall-MHD turbulence, and their consequences for constraining scaling relations and dynamical evolutions; (ii) the cascade processes of energy in three dimensional strongly rotating stratified turbulent flows (RST) found to be dual, in the sense that the energy can go in a self-similar manner both to the large scales and to the small scales with (different) contant fluxes, a phenomenon also encountered in MHD, including in solar wind observations; and (iii) turbulent fields themselves (velocity, induction, temperature), together with their gradients, can be intermittent with non-Gaussian wings, as in quantum turbulence and shear flows or in MHD and RST.
I will also mention old and new results concerning the propensity for turbulent flows and nonlinear systems to develop sharp, isolated (intermittent) structures at small and large scales in a variety of physical environments. This will be done in the specific context of normalized moments at third-order (skewness S) and fourth-order (kurtosis K). Indeed, intermittency can be evaluated e.g. through the examination of relations between S and K for fields such as the velocity, temperature and magnetic fields as well as for their local rates of dissipation. The field themselves, in general, have small skewness, but in some cases they display high kurtosis, such as for vertical velocities in RST, as observed in the stable nocturnal planetary boundary layer, as well as for the magnetic field in the solar wind, or more recently in the fast dynamo regime in MHD. On the other hand, the local dissipation rates of these fields follow a parabolic K(S) law whose origin may be linked to kinematic constraints, to the applicability of Langevin models to their dynamics, or to self-organized criticality, as suggested by several authors in various physical contexts, from the atmosphere, the ocean and climate, to fusion plasmas, the solar wind and dwarf galaxies [1,2].
Many thanks to all my collaborators, mentors, colleagues, students and post-docs.
[1] Annick Pouquet, Duane Rosenberg, Raffaele Marino and Pablo Mininni: Intermittency Scaling for Mixing and Dissipation in Rotating Stratified Turbulence at the Edge of Instability. Atmosphere 14, 1375 (2023). Special issue in honor of Jack Herring; B. Galperin, A. Pouquet & P. Sullivan Eds..
[2] Yannick Ponty, Hélène Politano and Annick Pouquet: Spatio-temporal intermittency assessed through kurtosis-skewness relations in MHD in the fast dynamo regime. In preparation (2024).
Importance of early 19th century volcanic activity on long-term climate variability.
Authors: Schurer Andrew , Ballinger Andrew , Dittus Andrea , Hawkins Ed , Cornes Richard , Kent Elizabeth , Morice Colin , Osborn Tim , Rumbold Steven , Hegerl Gabriele
Published: March 2024

Typically, climate simulations covering the historical period start in 1850, with the first fifty years used as a baseline to represent a ‘pre-industrial' climate. The period immediately prior to 1850 is however of particular interest, as it had far more volcanic activity than any time during the subsequent historical period, and this is known to have caused large cooling of global temperatures. Exploring the climate of this period could help to better understand early anthropogenic warming, natural climate variability and anticipate the response to large future eruptions.Here we will: (1) highlight the development of a new instrumental observation-based dataset (GloSAT) for temperature variations across the globe from 1781 to present; (2) discuss an ensemble of historical simulations with UKESM1 which were started in 1750, 100 years earlier than typical. These two sources of evidence will be used to identify the long-lasting impacts of the early 19th century volcanism and disentangle it from the response to other forcings and internal variations. Longer term effects of this period are also explored with significant differences found with historical simulations run using the same model initialised in 1850 lasting well into the 20th century. The implications of this discrepancy and the role of large volcanic eruptions on multi-decadal climate will be discussed. 
Evidence for Eurekan deformation within and around the Yermak Plateau, Arctic Ocean
Authors: Geissler Wolfram , Klitzke Peter , Eagles Graeme , Reinhardt Lutz , Weber Maximilian , Berglar Kai , Ruppel Antonia
Published: March 2024

The Yermak Plateau is a submarine plateau that lies to the north of Svalbard. Strong magnetic anomalies over its northeastern part led early interpretations of an origin by volcanic processes in an oceanic setting, during the formation of the SW Eurasia Basin and the Fram Strait between Svalbard and Greenland. However, subsequent geophysical research delivered evidence that at least the southern and northwestern parts of the plateau might be underlain by extended continental crust. This implies that plate reconstructions for times before the opening of the Eurasia Basin should account for these continental fragments. Up until now, the true northward extent of this microcontinent and neighbouring parts of Svalbard, and their late Cretaceous and Paleogene relative locations, have been incompletely known.Moreover, during the late Cretaceous and Paleogene, large areas along the Northern Canadian and North Greenland continental margins, as well as the West Svalbard and Southwest Barents Sea continental margins were affected by compressional and strike-slip deformation that culminated in at least two discrete phases together referred to as the Eurekan orogeny, which dates from 53 to 34 Ma. Considering that the continental fragments of Yermak Plateau were located to the north of Greenland or even north of the Canadian Arctic Islands, it is conceivable that the Eurekan deformation might have also left traces within or around the present-day Yermak Plateau.Here we report on evidence from seismic reflection data from the Sophia Basin, which separates the Yermak Plateau from Svalbard. Evidence for compressional and transpressional features beneath a Neogene-Quaternary sedimentary cover can be correlated to the two Eurekan deformation phases. Reconstructing the Yermak Plateau towards the North Greenland margin by closing the Neogene-Quaternary Lena Trough spreading system based on aeromagnetic data, we also found further evidence for continuity of geological structures between North Greenland and the northwestern Yermak Plateau.
Recent ice ages on Mars by destabilization of the Northern Polar Cap at 35° obliquity
Authors: Naar Joseph , Forget François , Millour Ehouarn , Vos Eran , Segonne Charlotte , Lange Lucas , Clément Jean-Baptiste , Montmessin Franck
Published: March 2024

Surface water ice is unstable on present-day Mars outside of the polar regions. However, prominent geological features show that during its recent past the surface of Mars was covered, on multiple occasions, by a « latitude-dependent mantle » (LDM) of water ice, from the polar regions to the tropics [1].Different studies conducted with Global Climate Models, in particular the Mars PCM (previously Mars LMD-GCM) led to the formulation of a climate scenario for the emplacement of ice ages : during high obliquity phases (>45°, as opposed to present-day ~25°), strong destabilization of the Northern Cap allowed for the aerial deposition of ice on the flank of tropical volcanoes, forming glaciers. When returning at lower obliquity, these glaciers were in turn destabilized but ice accumulated in the mid and high latitudes, and thus formed the observed surface ice deposits (LDM) [2]. However, the 45° obliquity excursions occurred before the last 5 million years, while the last ice age occurrence is dated of 400 000 years at most.Previous numerical experiments did not account for the radiative effect of water-ice clouds. Previous studies show that, even though somewhat negligible in the present-day Martian climate, this effect is overriding at higher obliquity with the intensification of the water cycle [3]. We have conducted new experiments at 35° obliquity with the Mars PCM using an improved physical package for the radiatively active clouds (RACs) and surface ice. Here, we present the resulting climate regime in our simulations. At 35° obliquity, the atmosphere is almost two orders of magnitude wetter than present-day, due to the greenhouse effect of RACs over the polar regions. In the high to mid latitudes, the seasonal winter ice accumulation is increased dramatically, while the summer sublimation is dampened by the latent heat cooling. Surface water ice thus accumulates at rates corresponding to tens of meters at each high obliquity excursion, reconciling the climatic scenario with the inferred age of emplacements of the LDM.References:[1] Head et al. (2003), Recent ice ages on Mars, Nature, 426, 797.[2] Madeleine et al. (2009), Amazonian northern mid-latitude glaciation on Mars: A proposed climate scenario, Icarus, 203, 390[3] Madeleine et al. (2014), Recent Ice Ages on Mars: The role of radiatively active clouds and cloud microphysics, Geophysical Research Letters, 41, 4873Acknowledgements:This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement No 835275).
Sustainable operation of a large BHE field considering groundwater flow and land cover changes
Authors: Liu Quan , Weiland Finn , Pärisch Peter , Kracht Niklas , Schuba Sven-Yannik , Ptak Thomas
Published: March 2024

Shallow geothermal energy has been widely used for heating and cooling buildings by combining borehole heat exchangers (BHEs) with heat pumps. In recent years, how to maintain the efficiency and sustainability of large BHE systems has received increasing attention. An effective way to address this issue is to develop site-specific models to accurately predict the economy, thermal efficiency, and environmental impacts of geothermal systems. However, site characteristics are often simplified or even ignored, such as complex groundwater flow induced by subsurface heterogeneity and non-homogeneous surface heat transfer due to various land covers. In this study, a BHE system model was developed based on collected site characteristics and thermal measurements during system operation. Firstly, groundwater flow in a heterogeneous subsurface was considered in the developed model, according to the regional hydrogeologic conditions and borehole logs. In addition, complex surface heat transfer influenced by solar radiation and land cover characteristics was incorporated. Thermal parameters of different land cover types are considered as time-varying parameters to account for neighboring land use changes. Finally, the hydraulic parameters in the developed model were calibrated by comparing simulations with the groundwater temperatures observed in the boreholes. Next, we plan to further validate the prediction capability of the developed model based on recent temperature observations. We will then discuss the importance of site characteristics in assessing the thermal efficiency and environmental impacts of the BHE system by comparing the results with those of simplified models. Forecasts of system economics for the next ten years will also be made based on the developed model and possible thermal energy management strategies.
A Novel Empirical EUV Model with Uncertainty Quantification
Authors: Brandt Daniel , Ridley Aaron
Published: March 2024

The ubiquitous usage of solar proxies in the nowcasting and forecasting of ionospheric and thermospheric conditions has seen the application of a multitude of techniques to ensure high fidelity representation of the effects of solar EUV forcing on the atmospheric state. The inherent limitations of reliance on a single solar proxy have encouraged the development of numerous EUV irradiance models in which the EUV irradiance in multiple bands is reconstructed from F10.7 solar flux. These models have progressed from lower to higher resolution, as well as higher-fidelity parameterization of time-varying components of the EUV irradiance. We contribute to this development in presenting NEUVAC, a simple, but novel empirical solar EUV model trained on FISM2 data. NEUVAC models the solar EUV irradiance from F10.7 and 81-day averaged F10.7 in 59 wavelength bands between 1 and 1750 Angstroms using a nonlinear parameterization, and performs uncertainty quantification in each band with the assistance of exclusively data-driven methods that exploit the dynamical properties of EUV, and intercorrelations between irradiance in each band. The irradiances provided by NEUVAC highlight the success of the FISM2 program, are suitable for direct ingestion into global ionosphere-thermosphere models, and are structured so that ensembles of irradiance estimates can be generated for principled forecasting and statistical assessment of downstream parameters generated by ionosphere-thermosphere models.
Gravimetric signature of subducted slabs’ deep thermal structures.
Authors: Vergeron Xavier , Cadio Cécilia , Garel Fanny
Published: March 2024

At subduction zones, cold lithospheric plates dive deep into the hotter Earth’s mantle. Earthquakes can occur at depths of hundreds of kilometers in these cold subducted slabs, apparently related to their thermal structures. Seismic tomography provides a first-order information on slab morphology but cannot discriminate « cold » from « warm » slabs partly due to the inhomogeneous repartition of seismic sources and surface sensors. This study investigates the potential of the gravity data from the GOCE mission to infer deep slabs’ inner thermal structures (> 200 km depth). Thermal structures of slabs with various morphologies are derived from dynamic subduction zones models. We convert temperature field into density assuming mineralogical phases at thermodynamical equilibrium for pyrolite mantle using HeFESTo model (Stixrude and Lithgow-Bertelloni 2011). We then use the freeware DynG3 (Cadio et al. 2011) to predict surface and CMB deflections due to slab dynamic sinking – depending on the radial mantle viscosity – and calculate the corresponding synthetic signals (geoid, gravity disturbance, gravity gradients). Our parametric study considers various radial mantle viscosity profiles, slab morphologies and slabs inner thermal structures (SITS). As expected, geoid and gravity gradients are sensitive to density anomalies at different depth ranges. We highlight linear relationships between both these signal for a given viscosity profile and a given slab’s morphology :
First, the colder an isothermal slab, the higher the geoid and gravity gradients anomalies.

Second, for a given shallow temperature, the colder the deep slab (>500 km), the lower the gravity gradient anomaly and the higher the geoid anomaly.

This last, counter-intuitive, result is explained by the fact that the long wavelength component associated to deep density anomaly overprints, for colder slabs, the short wavelength component associated to surface deflection. Thus, for a known viscosity profile and slab morphology, both shallow (~ 200-500 km depth) and mean slab thermal structures could be inverted from the combination of geoid and gravity gradients anomalies.
The impact of forest canopy structure on the understory microclimate: a physics-based approach and sensitivity analysis
Authors: Bouwen Klara , Domec Jean-Christophe , Charru Marie , Ogée Jérôme
Published: March 2024

Forest canopies can buffer or amplify macroclimate temperature extremes in their understory depending on structural and ecological parameters such as canopy height, canopy openness, and species composition. Forest management practices that alter these parameters have a strong impact on understory temperature extremes, with potential repercussions on forest resilience to climate change.Physics-based microclimate models offer a means to explore the effects of forest canopy structure on understory temperatures. Compared to empirical models, they allow to extrapolate results outside the range of canopy structure and climatic conditions that have been observed so far. Although physics-based models may differ in their representation of soil-vegetation-atmosphere interactions, they all rely on a priori knowledge of meteorological data above the forest (also called climate forcing), including air temperature, relative humidity and wind speed timeseries. This raises challenges when conducting sensitivity analyses on structural parameters because canopy structure influences the microclimate not only inside and below the forest canopy but also above it. Employing the same climate forcing for all scenarios of canopy structure is thus deemed inappropriate and adjustments of climate forcing must be accounted for.In this study, we propose a new physics-based modelling approach to perform sensitivity analyses of canopy structure on understorey microclimate that incorporates the feedback of a change in canopy structure on the climatic conditions above it. This approach relies on existing theories on the similarity of turbulent flux-gradient relationships within the atmospheric surface boundary layer between different scalars (e.g. air temperature and humidity) and wind speed, adapted to rough surfaces such as forest canopies. This approach is tested against datasets collected in various forest ecosystems across Europe and applied to explore the impact of canopy structure, in particular canopy density and clumping, on understory microclimate. Our approach will advance our understanding of the intricate relationships between canopy structure, boundary layer dynamics and microclimate, offering insights for more effective forest management strategies.
Participation in climate change adaptation 
Authors: Komendantova Nadejda , Erokhin Dmitry
Published: March 2024

This paper presents a comprehensive analysis of participatory elements in climate change adaptation policies at both the EU level and within national contexts, focusing on Germany and Spain. The study delves into the crucial role of co-production and citizen engagement in shaping effective climate adaptation strategies. The research methodology involves policy identification and selection, analysis of participatory elements, and the application of Arnstein's ladder of citizen participation to evaluate the level of citizen engagement in the identified policies. The analysis reveals the diverse mechanisms and approaches employed to foster inclusive and participatory processes in climate adaptation policies. The study highlights the significance of stakeholder involvement, consultation mechanisms, transparency, capacity building, and feedback mechanisms in shaping robust climate adaptation strategies. Furthermore, it underscores the importance of citizen participation in driving transformative climate adaptation initiatives, emphasizing the need for broad geographical representation, inclusive approaches, and the integration of diverse knowledge systems. The study identifies gaps and areas for improvement in the participatory elements of the analyzed policies, emphasizing the need for more comprehensive mechanisms to engage the general public and vulnerable communities in the adaptation planning process. It also underscores the importance of systematic studies of gaps and barriers to stakeholder participation and the representation of marginalized communities in adaptation planning and decision-making processes. The paper offers valuable insights into the participatory elements of climate change adaptation policies, providing a nuanced understanding of the approaches employed at both the EU and national levels. The findings contribute to the ongoing discourse on inclusive and effective climate adaptation strategies, emphasizing the need for continuous improvement and the meaningful involvement of diverse stakeholders in shaping resilient climate futures.
Added value of AOD assimilation in synergy between MODIS and CALIOP instruments in MOCAGE.
Authors: Ayouzi Abdennacer , El Amraoui Laaziz , Pannekoucke Olivier
Published: March 2024

The aim of this study is to evaluate the added value of the assimilation of MODIS and CALIOP in synergy. The observations issued from both instruments will be assimilated in the CTM MOCAGE model in terms of Aerosol Optical Depth (AOD) for MODIS and backscatter, or extinction coefficient for CALIOP.  The objective is to improve the spatial representation of AOD by carrying out a comparison between the analyses and AERONET observations in terms of AOD. The assimilation model will  run with a global configuration of 1° x 1° (longitude x latitude) in a pre-operational context. The analyses concerning the synergy assimilation will be compared first the separate assimilations of the two instruments in order to assess the assimilation scores. The methodology will consist of debiasing both observations before the assimilation exercise. We will give more details about the application of this technique. The debiasing coefficient will be  applied to one kind of observation in order to make the two datasets consistent. Finally, we will evaluate the capability of the synergistic assimilation to better represent the tri-dimensional distribution of aerosol within the model compared to the individual assimilations.
Spatial and temporal structure of normal and extreme rainfall
Authors: Bárdossy András
Published: March 2024

The space time behaviour of precipitation is very complex. The knowledge of the dependence structures in space and time is very important for the assessment of flood risks. In this contribution the dependence structures of normal and extreme events are compared. Both rain gauges with high temporal resolution and radar images are investigated. Spatial and temporal copulas are used for this investigation. Due to the large number of zero observations, especially for short temporal aggregations an indicator approach is used to detect structural differences. The results show, that the temporal dependence structure of rainfall gradually changes with increasing intensity. Similar behaviour can be detected for the spatial structure with the addition of advection related differences in both ranges and angles of anisotropy. The findings indicate that metagaussian approaches which only consider spatial and temporal correlations are not appropriate for the description and the simulation of rainfall extremes. Finally a new structural simulation method using non-Gaussian dependence is presented.
A new synthesis of Arctic-boreal carbon fluxes for improved carbon budget estimates
Authors: Virkkala Anna , Wargowsky Isabel , Vogt Judith , Kuhn McKenzie , Natali Susan , Rogers Brendan , Goeckede Mathias , Arndt Kyle , Watts Jennifer , Windholz Tiffany , Madaan Simran
Published: March 2024

The Arctic-boreal zone and its permafrost regions have historically been sparsely measured for carbon dioxide and methane fluxes. This data sparsity has created significant uncertainties in Arctic-boreal carbon budget estimates. However, over the past decade, the availability of Arctic-boreal carbon flux data has increased substantially. Yet, it remains scattered across different repositories, papers, and unpublished sources, making it hard to estimate more accurate Arctic-boreal carbon budgets. To address this research gap, we have compiled a database of Arctic-boreal carbon fluxes (ABCFlux v2) from flux repositories, literature, and site principal investigators, which will be openly distributed. The database includes carbon dioxide fluxes of gross primary production, ecosystem respiration, and net ecosystem exchange, and plant-mediated, diffusive, ebullitive, and storage methane fluxes measured with eddy covariance and chamber techniques with supporting methodological and environmental metadata from terrestrial (including wetland) and freshwater ecosystems. It has in total over 12,000 site-months and 30,000 unique monthly flux values, therefore almost doubling earlier synthesis efforts in the region. Here, we present preliminary results on carbon flux magnitudes across key land cover types and multidecadal trends based on the in-situ data and machine-learning based upscaling. These indicate, for example, that the Arctic-boreal region has been an increasing annual terrestrial net ecosystem CO2 sink with the boreal biome primarily driving this trend. This collaborative initiative, involving contributions from over 100 researchers, serves as an important step in reducing uncertainties in Arctic-boreal carbon budgets and enhancing our understanding of climate feedbacks.
Solar wind-driven Alfvénic energy flow in the dayside magnetosphere
Authors: Keiling Andreas
Published: March 2024

There is ample evidence for significant Alfvénic activity in the dayside magnetosphere. One reported aspect has been the relationship between the IMF/solar wind parameters and the global Alfvénic Poynting flux in the coupled system. In this investigation, we add to the body of knowledge by presenting the dynamics of Alfvén waves as a global phenomenon as it occurs at the entry point to the dayside auroral acceleration region. In particular, we show how the global Alfven wave power and morphology evolves during geomagnetic storm developments, from storm sudden commencement to the end of storm recovery. To investigate this, we used data from the Polar satellite. By comparing our results with observations from low-altitude satellites, we demonstrate the dissipation of Alfvénic power in the dayside. During storms, the transfer of energy from the solar wind into geospace is largely increased, leading to enhanced energy transfer and deposition within the magnetosphere and ionosphere. Here, we are aiming to understand the wave aspect during storm evolution.
Revisiting the implications of cliff-height dependent calving law on West Antarctic glaciers
Authors: Sun Sainan , Gudmundsson G. Hilmar
Published: March 2024

High-end estimates of sea-level change from Antarctica have been derived from simulations using upper-end forcing scenarios and ice-cliff height dependent calving laws. Those have been hypothesised to cause collapse of glaciers in West Antarctica through marine ice cliff instability (MICI). However, some previously published high-end estimate are based on results from a limited number of ice-sheet models, or even only a single ice-flow modelling study. There is, furthermore, low agreement on the implications of some of those calving laws for the West Antarctic Ice Sheet, and limited evidence of MICI having occurred in the past. Here we investigate the dynamic response of West Antarctic glaciers to high-end calving laws using the Úa ice-sheet model. Specifically, we conduct ice-shelf collapse experiments as defined in ABUMIP (Sun et al., 2020) with and without cliff failure mechanism in transient simulations conduced over centennial time scales. We find that the ice-cliff height dependent calving laws can cause glaciers to retreat and collapse from both fast and slow flowing regions. Furthermore, we find that the results are sensitive to numerical resolution near the grounding line. We suggest therefore that ice-sheet modellers always conduct convergence studies when implementing high-end calving laws.
The impact of time series length and temporal resolution on wind resource assessment: a comparative analysis of wind speed distributions
Authors: Zhou Lihong , Esau Igor
Published: March 2024

In the quest for accurate wind resource assessment crucial for the expansion of wind farms, this study tackles the scientific question of how varying time series lengths and temporal resolutions impact the estimation of wind resources, and introduce uncertainty into the assessment process. Recognizing the significant importance of considering temporal variability in wind speed distribution, we utilize in-situ observations from weather stations provided by the Norwegian Meteorological Institute, analyzing 1-hourly data spanning one to ten years. The study employs a comparative analysis of various wind speed distributions to determine the best-fit distribution for estimating wind resources. This process involves assessing the goodness-of-fit for each distribution under different time series lengths. Additionally, the study investigates the impact of temporal resolutions by examining data collected at 10-minute, hourly, daily, and monthly intervals from the same period and stations. The overarching goal is to systematically quantify uncertainty in wind resource estimation arising from the selection of wind speed distribution based on varying lengths and resolutions of time series data. The outcomes of this research aim not only to enhance the precision of wind resource assessments in the wind power sector but also to provide valuable insights applicable to fields influenced by wind conditions, including risk management and construction design. This study is financed by the Equinor academia project.
Assessing the dynamics of turbiditic terminal lobes: a geometrical approach
Authors: Grimaud Jean-Louis , Mercier Louison , Ors Fabien , Huyghe Damien
Published: March 2024

Terminal lobes constitute the endmembers of siliciclastic systems. They are of great interest to marine geologists and constitute high-quality reservoirs actively sought out and exploited by the oil and gas industry. The sizes and shapes of lobes vary depending on the type of sedimentary system and the nature of associated gravity flows. Sea bottom topography -induced either by preexisting lobes or mass transport deposition or tectonic deformation- is another important factor controlling lobe morphology. Previous studies carried out on recent systems (based on multibeam bathymetry and 2D/3D seismic data) show different shapes, classically characterized as lobate, but also radial or elongated. Currently, much remains to be known on the relative influences of autocyclic and allocyclic forcings on the internal architecture of lobes.This study focuses on a better definition of lobe shapes in natural systems to build a ruled -based model of lobes that will later be incorporated into the FLUMY© software. To this end, a database is built based on cases from the literature in various systems (e.g., the Congo, Amazon, Indonesia and East Corsica). We use the classical shape ratios defined by Prélat et al. (2010) as well as a new metric, called the progradation factor (PF), defined as the length ratio between the upstream and downstream segments of lobes (i.e., with respect to their centroids).Measures of PF were applied at different scales from the bed element to the lobe complex. Independently of the sedimentary system type, three different shapes of lobate bodies were identified: (i) a “classical” lobate shape -wider downstream- when PF > 1.15, (ii) lobes that are wider upstream when PF < 0.85 and, (iii) an elliptical shape when 0.85 ≤ PF ≤1.15. The classical lobate shape is interpreted as marking the absence of topographic confinement. Elliptical lobes occur mainly during maximum and minimum of progradation/retrogradation cycles. Lobes that are wider upstream result from topographic confinement and are mainly deposited at the end of retrogradation cycles. Finally, plotting thickness vs area allows identifying semi-confined lobes as a third category located between confined and unconfined lobes. This category follows a linear trend and exhibits a minimum thickness of 20 m.
A tool for objective detection of abrupt transitions in CMIP6 models
Authors: Lembo Valerio , Corti Susanna , Angevaare Joran , Drijfhout Sybren
Published: March 2024

We present here a tool for the detection of abrupt transitions in CMIP6 model outputs, that is aimed to update and extend the catalog of tipping points presented in Drijfhout et al. 2015, based on the evaluation of CMIP5 intercomparison.The tool consists of three fundamental steps: Data manipulation: model outputs are sampled according to the user’s preferences, aggregated along the integration period and interpolated to a common grid for the whole multi-model ensemble. A 10-years moving average is also applied;
Criteria for abrupt transitions: Criteria for the detection of abrupt transitions are computed and combined. These are: exceedance of the preindustrial 99-percentile standard deviation, exceedance of the preindustrial 99-percentile jump over 10 years period, exceedance of the preindustriak 99-percentile yearly anomaly for each year in the last 30 years of the simulation, p-value of a Kolmogorov-Smirnov hypothesis test for normality of the distribution;
Masking and clustering: grid points for which the time series of anomalies with respect to preindustrial conditions that satisfy at least 3 out of 4 of the criteria illustrated above are selected. Successively, grid points are clustered in order to exclude sparse points and highlight significant regions affected by widespread abrupt transitions;
We present a preliminary analysis demonstrating the usage of this tool on a set of ocean-sea-ice-related quantities for a number of models participating in CMIP6 project under disparate SSP scenarios. 
"Up-Goer Five Challenge": A way to make science more accessible?
Authors: Aglas-Leitner Philipp , Colin Maxime , Muller Caroline Jane , Hwong Yi-Ling , Sherwood Steven
Published: March 2024

Scientists of all fields share a duty to communicate their findings to the public. This is especially true in a time where false claims spread like wildfire and the correct information has a hard time receiving the necessary attention. Therefore, a multitude of different science communication approaches has been developed, including the so-called "Up-Goer Five Challenge". In recent years, this particular approach, sparked by an XKCD comic blueprint of the Saturn V Rocket, has become very popular among many science communicators and has even made its way to several scientific conferences.
The aim of this challenge is to encourage scientists to describe their research or other complex scientific topics in very simple terms, by only using the thousand most commonly used words. Apart from encouraging scientists to rethink jargon-loaded presentation styles, this approach has the advantage of potentially reaching a very broad audience by making science more accessible and at the same time inspire researchers to improve their communication skills and even see their own work from a different angle. However, this communication method will, of course, also come with certain downsides, as for example, depending on the audience, a very rigid application of the rules of the game might end up being more of a hurdle than a beneficial way of presenting complex issues.
Here is an example describing an atmospheric phenomenon called "Convective Memory":
Each day, when we look up in the sky, we can see those white soft-looking flying things above our heads. Sometimes they are tiny. One piece here, and another further away. But on some days, they can get really big and dark. Even kind of angry-looking. And then we, very often, wonder "Why do you have to be above my head and not somewhere else?"
One of the reasons is that this flying sky water has a very good memory and obviously likes to stay where it is: "I very much enjoy it here. I don't care if those humans down there are annoyed with me."
This memory works a bit like the piece of paper that you take with you when you go shopping so you don’t forget what to buy. This way, you can’t easily forget what you wanted to buy and stick to the stuff you need. This will help you even if the store owner decides to move some or all of the shopping goods in the store to another place. Thanks to that store owner, it is possible that you end up with "new" stuff that was not planned but you will at least have your piece of paper (your memory) to get the stuff you really need (see Maxime Colin 2020). The white flying things in the sky are like people going shopping: with a good memory, they stick to what they are, and do not become "new" and bigger so easily.
In this talk, we present the "Up-Goer Five Challenge" as applied to Convective Memory, discuss some challenges faced in using it, and offer potential remedies.
Sensitivity Analysis of Digital Elevation Models in Geoid Modelling for Indian region
Authors: Kumar Alok , maurya Vipin , dwivedi Ramji
Published: March 2024

Digital Elevation Models (DEMs) are fundamental components in geodetic computations, serving as key inputs in geoid modelling processes. Mostly, the freely available DEMs are used for geoid modelling without considering its impact on the developed geoid. Considering the criticality of terrain and downward continuation corrections calculated from DEMs, this research work explores the sensitivity of geoid models to variations in DEMs, aiming to elucidate the impact of different DEMs on the accuracy and precision of geoid modelling. The study aims at a comprehensive sensitivity analysis framework to assess the influence of DEM resolution, terrain representation, and fitting methods on regional geoid modelling in India. The selected study area consists of three states of India (Haryana, Punjab, and Himachal Pradesh) bounding approximately 169,500 km2 of the area (73.5≤λ≤77.5 and 29≤ϕ≤33 of longitude and latitude, respectively) of vast topography including Indo-Gangetic Plain, Shivalik Hills, lofty hills, deep valleys, and verdant forests. This study employs Least Squares Modification of Stokes formula with Additive Corrections (LSMSAC) method developed by the Royal Institute of Technology, Sweden and evaluates four DEMs, Cartosat, Merit, Palsar and SRTM. For surface correction (fitting), 24 GNSS points are used with 4,5 & 7 parameter fitting models which is validated with 15 other GNSS point based on elementary statistics. This investigation offers insights into selection of an optimal DEM by obtaining RMSE between developed geoid using various DEMs and 15 GNSS points. Based on the obtained results by considering above-mentioned DEMs with various fitting models, the Cartosat DEM outperformed other DEMs by obtaining lowest RMSE (0.078603m) with 7 parameter fitting model. Surprisingly, the lowest RMSE (0.064557m) is obtained by Cartosat DEM with 4 parameter model which could be because of Cartosat DEM being an India specific DEM. While comparing the efficacy of developed geoid between globally available DEM, Merit performed best with lowest RMSE (0.078657m). Out of 90 combinations of each DEM for various sets of Degree/order of Global Geopotential model (GGM), integration cap size; the best result is obtained by 180 degree of GGM and 0.8 integration cap size for each DEM. Presented study improved our understanding in assessing the sensitivity of geoid models to various DEMs. This research aids geodesists, geophysicists, and remote sensing specialists in making informed decisions while selecting a suitable DEM for geoid computations. The findings presented in this paper contribute to the ongoing efforts to enhance the precision and reliability of geoid modelling techniques, ultimately improving our understanding of Earth's gravity field.
ClimateMeter: Putting Extreme Weather Phenomena in Climate Perspective 
Authors: Faranda Davide ,   The ClimaMeter Team
Published: March 2024

Climate change is a global challenge with manifold and widespread consequences, including the intensification and increased frequency of numerous extreme weather phenomena. In response to this pressing issue, we introduce ClimaMeter, a platform designed to assess and contextualize extreme weather phenomena in relation to climate change. The platform provides near-real-time information on the dynamics of extreme events, serving as a resource for researchers, policymakers, and acting as a scientific outreach tool for the general public. ClimaMeter currently analyzes heatwaves, cold spells, heavy precipitation, and windstorms. This presentation sheds light on the methodology, data sources, and analytical techniques that ClimaMeter relies on, offering a comprehensive overview of its scientific foundations. To illustrate ClimaMeter, we present some examples of recent extreme weather events. Additionally, we highlight the role of ClimaMeter in promoting a profound understanding of the complex interactions between climate change and extreme weather phenomena, with the hope of ultimately contributing to informed decision-making and climate resilience. Follow us on X @ClimaMeter and visit www.climameter.org.

 
 

 
Deformation history and P-T condition of metamorphism of Gadag greenstone belt of western Dharwar craton, southern India: Implications on the genesis of orogenic gold mineralisation
Authors: Saikia Manash Jyoti , Chinnasamy Sakthi Saravanan
Published: March 2024

The Late Archean Gadag greenstone belt (GGB) in the northern continuity of extensive Chitradurga greenstone belt in the western Dharwar craton has extensive meta volcano-sedimentary cover apart from older TTGs (Tonalite-trondhjemite-granodiorite), pink granite and other intrusives. The GGB encompasses a very unique and classical orogenic type gold deposit known as Gadag gold field (GGF) where auriferous lodes are hosted by metabasalt, greywacke and BIFs in western, central and eastern part of GGF respectively. In this study, we focus on the deformation history and P-T conditions of metamorphism of greenstone rocks which could have influenced in the generation of auriferous fluid in GGB. Two events of deformation were suggested in GGB so far where the first event (D1) is represented by NW-SE trending pervasive fabrics (S1) and schistocity, whereas the second event (D2) marking the regional disposition of NNW-SSE tectonic trend. This is further corroborated by microscopic evidences of Q-M microlithons development and garnet porphyroblast growth that is post tectonic to D1 deformation, syn-tectonic to early D2 and stage 2 porphyroblast development of non-rotating porphyroblast model in garnetiferous amphibolite in the north-eastern part of GGB. However, the matrix continued to get deformed and reached stage 6 in garnetiferous schist with dominant sinistral sense of shear in the southern part of GGB. The estimated peak metamorphic temperature of garnetiferous amphibolite using hornblende-plagioclase thermobarometry is 578 ± 21°C and the pressures are 7.1 ± 3kb and 7.4 ± 2.3kb. Garnet-biotite thermometric estimation for the same garnetiferous amphibolite from north eastern part of GGB yielded 525 ± 25°C indicating a lower amphibolite facies of metamorphism. The auriferous quartz veins were associated with both the D1 and D2 phases of deformation, and the genesis of this auriferous fluid may be related to lower amphibolite facies of metamorphism of these host rocks as evidenced from the fluid inclusion study.Keywords: craton, P-T conditions, thermobarometry
Water Mass Changes and Carbon Uptake by Subantarctic Pacific Waters
Authors: García-Ibáñez Maribel I. , Pardo Paula C. , Brown Peter J. , Lee Gareth , Martin Adrian , Oliver Sophy , Pabortsava Katsia , Trucco-Pignata Pablo , Bakker Dorothee C.E.
Published: March 2024

The Southern Ocean (SO) is a critical component of the global carbon cycle, acting as a significant sink for atmospheric carbon dioxide (CO2). Understanding the intricate processes governing CO2 uptake in the SO is paramount for comprehending the global carbon budget and predicting future climate scenarios. Recent observations suggest that changes in SO water masses, driven by climate-induced alterations in temperature and circulation patterns, can significantly impact CO2 uptake. Understanding these feedbacks is crucial for predicting the SO's future role as a carbon sink and its broader implications for climate mitigation efforts. In this work, we determine changes in the water mass composition and their characteristics, including their CO2 content, along the CUSTARD transect (54ºS-59ºS 90ºW) in Subantarctic Pacific waters. The CUSTARD transect crosses a region of formation of mode and intermediate waters. We use an extended Optimum Multiparameter (eOMP) analysis and data from three repeats of the CUSTARD transect in 1993 (expocode 316N19930222; data from GLODAPv2.2023), 2005-2006 (316N20050821 and 316N20060130; from GLODAPv2.2023), and 2019-2020 (74EQ20191202; the CUSTARD cruise). We observe isopycnal heaving in the southern part of the transect from 1993 to 2020. In the upper ocean (neutral density (γn) < 27.2 kg m-3), isopycnal heaving is linked to a temperature decrease of up to -2ºC and a salinity decrease of up to -0.15 between 1993 and 2005, extending to γn < 27.5 kg m-3 in 2019-2020. The physicochemical changes in the upper ocean are linked to changes in the water mass composition, including an increase in the volume of Antarctic Surface Water and Antarctic Intermediate Water and a decrease in the volume of SubAntarctic Mode Water over the 18-year study period. These water mass changes are accompanied by decreases in concentrations of oxygen, dissolved nutrients, and total alkalinity, along with an increase in total dissolved inorganic carbon of up to 40 µmol kg-3  for γn < 27.5 kg m-3 from 1993 to 2019-2020. For 27.5 kg m-3 < γn 28.2 kg m-3), Ross Sea Bottom Water replaces Adélie Bottom Water from 1993 to 2019-2020. The changes in water mass composition observed along the CUSTARD transect indicate circulation variations linked to the Southern Annular Mode (SAM), with a prevalent positive phase since 1995. Positive SAM pahses increase upwelling south of the Antarctic Polar Front and downwelling in the Subantarctic Zone. Due to these circulation changes, the SO’s uptake of atmospheric CO2 decreases during positive SAM phases, which are predicted to intensify with climate change.
Visualization of Real-time Processed Multibeam SONAR Data for 3D Water-column Reconstruction
Authors: Kanarski Christian , Kaulen Bastian , Kühne Frederik , Gussow Karoline , Röhrdanz Finn , Driesen Marco , Karatziotis Konstantinos , Greinert Jens , Schmidt Gerhard
Published: March 2024

The use of multibeam MIMO-SONAR systems on marine vehicles (e.g. remotely operated vehicles, ROVs) enables the visual 3D reconstruction of the water-column by hydroacoustic ensonification of the surrounding environment in real-time. For underwater target detection and classification purposes, the processed SONAR data must be visualized for interpretation of the results by a human operator and to allow for a corresponding re-adjustment of the system parametrization during operation. Therefore, conventional 2D visualization approaches such as the plan position indicator (PPI) plot must be adapted to 3D. Challenges such as different signal-to-noise ratios, beamforming artifacts, and overlapping objects must be considered when choosing how to visualize the processed data to allow for the correct semantic interpretation of the scanned water-column.In this presentation, an approach for the 3D voxel- and mesh-based visualization of real-time processed multibeam SONAR data is shown. The focus will be on how to consider the 3D beamforming and signal correlation processing, combined with data interpolation and filtering techniques, to allow for a visual reconstruction of the water-column from the SONAR data. An implementation of this approach in the C++ programming language using the Qt visualization framework will be shown in the Kiel Real-time Application Toolkit (KiRAT) for a virtual ocean environment.