bluuebunny/crossref_metadata_2025 huggingface dataset:
Satellite observations for runoff and river discharge estimation: STREAMRIDE approach 
Authors: Camici Stefania , Tarpanelli Angelica , Brocca Luca , Massari Christian , Nielsen Karina , Sneeuw Nico , Tourian Mohammad J. , Yi Shuang , Restano Marco , Benveniste Jérôme
Published: March 2022

River discharge monitoring is crucial for many activities ranging from the management of water resources to flood risk mitigation. Due to the limitations of the in situ stations (e.g., low station density, incomplete temporal coverage as well as delays in data access), the river discharge is not always continuously monitored in time and in space. This prompted researchers and space agencies, among others, in developing new methods based on satellite observations for the river discharge estimation.

In the last decade, ESA has funded the SaTellite based Runoff Evaluation And Mapping and River Discharge Estimation (STREAMRIDE) project, which proposes the combination of two innovative and complementary approaches, STREAM and RIDESAT, for estimating river discharge. The innovative aspect of the two approaches is an almost exclusive use of satellite data. In particular, precipitation, soil moisture and terrestrial water storage observations are used within a simple and conceptual parsimonious approach (STREAM) to estimate runoff, whereas altimeter and Near InfraRed (NIR) sensors are jointly exploited to derive river discharge within RIDESAT. By modelling different processes that act at the basin or at local scale, the combination of STREAM and RIDESAT is able to provide less than 3-day temporal resolution river discharge estimates in many large rivers of the world (e.g., Mississippi, Amazon, Danube, Po), where the single approaches fail. Indeed, even if both the approaches demonstrated high capability to estimate accurate river discharge at multiple cross sections, they are not optimal under certain conditions such as in presence of densely vegetated and mountainous areas or in non-natural basins with high anthropogenic impact (i.e., in basin where the flow is regulated by the presence of dams, reservoirs or floodplains along the river; or in highly irrigated areas).

Here, we present some new advancements of both STREAM and RIDESAT approaches which help to overcome the limitations encountered. In particular, specific modules (e.g., reservoir or irrigation modules for STREAM approach) as well as algorithm retrieval improvements (e.g., to take into account the sediment and the vegetation for RIDESAT algorithm) were implemented. Furthermore, in order to exploit the complementarity of the two approaches, the two river discharge estimates were also integrated within a simple data integration framework and evaluated over sites located on the Amazon and Mississippi river basins. Results demonstrated the added-value of a complementary river discharge estimate with respect to a stand-alone estimate.
Application of unsupervised machine learning techniques for lithological and soil mapping in Ossa-Morena Zone
Authors: Silva Marcelo , Nogueira Pedro , Henriques Renato , Gonçalves Mário
Published: March 2022

Unsupervised methods are a good entry point for satellite image classification, requiring little to no input, and outputting an analysis, in the form of a thematic map, that may act as a guide for more user input intensive methods. For this work, we use K-means methods to classify satellite and drone imagery that cover the Ossa-Morena Zone (OMZ), in Portugal, and assess their capacity for lithological and soil mapping. The drone is equipped with a High Precision NDVI Single Sensor and was flown over the ancient mines of Mociços, Mostardeira and Santa Eulália. The OMZ is a tectonostratigraphic domain shared between Portugal and Spain, divided in Sectors, extraordinarily rich and diverse from a lithological, stratigraphical, and structural point-of-view; for this work, we will focus on the Estremoz-Barrancos sector, comprised of a Neoproterozoic to Devonian metasedimentary succession, with a low-grade metamorphism in greenschist facies, and the Santa Eulália Plutonic Complex (SEPC), an elliptic late-Variscan granitic massif that crosscuts the Alter do Chão-Elvas Sector and the Blastomylonitic belt, constituted by two granitic facies, a few small mafic bodies, and some roof pendants that belong to the Alter do Chão-Elvas Sector.

The imagery used correspond to high-level satellite imagery products gathered between 2004 to 2006 (ASTER) and 2017 to 2021 (Landsat 8 and Sentinel-2), and drone imagery captured on May 6th and August 31st, 2021.

The K-means was applied to a variable number of selected bands, including band ratios, and tested for different number of initial clusters and different distance algorithms (Minimum Distance and Spectral Angle Mapping). Afterwards, it was assessed its ability to outlining and classify different geological structures by comparing the results to the geological map of OMZ.

The obtained thematic maps points towards poorer results when using a larger selection of bands - for instance, ASTER bands 1 to 9 (in which bands 1 to 3N were resampled to 30m) -, due to interspersion of different classes, whereas when using band ratio combinations, such as 4/2 and 6/(5+7) (ASTER), the produced map successfully classifies the major geological features present in the region, with increased sharpness between contacts with a higher number of classes.

Results show that K-means, when used under the correct conditions and parameters, has the potential for lithological and soil mapping through image classification, both for satellite and drone imagery.

Future work will focus on the integration of a pre-processing step for band selection using ML techniques, such as through Principal Component Analysis, Minimum Noise Fraction and Random Forest.
Multiscale characterization of chaotic rock body for mining backfill remediation
Authors: Caselle Chiara , Bonetto Sabrina Maria Rita , Mosca Pietro , Paschetto Arianna , Vianello Davide , Garello Andrea , Paletto Fabio
Published: March 2022

The sustainability of geomineral resourses’ exploitation may be assured only in presence of adequate plans for the re-use and reclamation of old or abandoned sites. Among the most commonly used techniques, mining backfill is largely employed for the stabilization of underground sites. This technique recreates the original stress state of the underground, assuring the definitive stabilization of the hypogea volumes, and reduces the risks due to the interference between underground tunnels and ground surface (e.g. possible collapses and surface subsidences). Despite these obvious advantages, careful evaluations are needed to assure the environmental sustainability, with particular attention to the interaction between the hydro-geological and permeability features of the rock body and the chemical properties of the backfill material.

The present research proposes an analysis of the advantages and the risks connected with this technique, examining a case study of mining backfill in an underground gypsum quarry at the end of the active exploitation. The considered quarry is located in Monferrato (NW Italy) and is exploited within chaotic Messinian deposits made of gypsum blocks (from centimeter-size to kilometer-size) included in a marly matrix. The study includes a campaign of field and laboratory tests (i.e. geological and geo-structural mapping and modeling, geophysical surveys, mechanical and permeability tests) that aim at characterize the permeability and mechanical behaviour of the rock mass.
Sustainable floods: Exploring stakeholder perceptions of sedimentation strategies for the sinking Mekong delta
Authors: Dunn Frances , Quee Niki , Luu Tang , Tang Phuong Gian , Triyanti Annisa , Du Haomiao , Wyatt Andrew , Minderhoud Philip , Sieben Eline
Published: March 2022

The Mekong delta in Vietnam, home to over 17 million people, is rapidly losing elevation due to groundwater-extraction-induced subsidence, natural compaction and global sea-level rise. These combined processes result in salinity intrusion, erosion and land loss. The delta has been extensively poldered for agri- and aquaculture, largely cutting off the land from the dwindling supplies of fluvial sediment which would otherwise accumulate on the delta during seasonal floods and increase land elevation. Considering the current state of the Mekong delta and sediment delivery from upstream, the future sustainability of the delta cannot rely on natural delta-building processes and instead must be planned and managed to prevent major degradation of the system.

Sedimentation strategies are methods of ensuring that the limited sediment available is retained to increase elevation where it is desirable for the population and sustainability of the delta. Considering the potential disruption to land uses and livelihoods caused by sedimentation strategies, it is vital to discuss the possibilities for sedimentation strategies with stakeholders to ensure that people, particularly vulnerable groups, are not disadvantaged, and ensure that delta management is sustainable from all perspectives. In this research we engage with stakeholders to start an explorative dialogue on the potential of sedimentation strategies in the Mekong delta considering physical, socio-institutional, governance and legal aspects. We present an analysis of interviews and workshop discussions with farmers, officials, and regional experts in the provinces of Soc Trang (coastal, the most downstream part of the delta) and An Giang (inland, the most upstream part of the delta) to gain insights into local perspectives in different areas of the delta, with different physical environments, land use histories and constraints.

Preliminary findings suggest that the perceived role of sediment varies across different stakeholders e.g. farmers focus more on the role of sediment for their agricultural activities while experts also express their concerns on the elevation of the delta. Interestingly, while sediment is perceived to be important in the upstream area, it is considered an inconvenience in the downstream part of the delta due to, among other factors, different types of livelihoods. It is therefore recommended that the sedimentation strategies need to be designed based on the typical livelihoods of locals and communication strategies need to be enhanced to raise the awareness of local actors on the role of sediment.
Investigation of the ductile-to-brittle transition in snow with compression tests and tomography monitoring
Authors: Bernard Antoine , Montagnat Maurine , Chambon Guillaume , Hagenmuller Pascal
Published: March 2022

Once fallen on the ground, snowflakes evolve quickly and form the snowpack. Under its own weight, the snowpack slowly deforms and settles. On a steep slope, some layers may rapidly deform and fail, which yield to the release of an avalanche. At the macroscopic scale, snow mechanical behavior is highly strain-rate dependent: ductile at low strain rates and brittle at high strain rates. The ductile-to-brittle transition has recently been shown to occur in two stages, with an intermediate regime of intermittent brittle failures, assumed to result from a competition between different time scales. At the micro-scale, this mechanical behavior is controlled by the microstructure and the visco-plastic and sintering properties of the ice skeleton. In this work, we investigate snow brittle-to-ductile transition by conducting displacement-controlled compression tests monitored with X-ray micro-computed tomogaphy.

We specifically designed a loading apparatus to perform displacement-controlled compression tests in cold environment and the constrained space of the tomographic cabin, so that microstructure evolution could be followed by regular scans. Samples (14 mm in diameter, 14 mm in height) were prepared from natural snow, sieved directly into samples holders, in batch of 10 samples and sintered for 72h at -20°C then stored at -50°C to prevent further microstructure evolution. The sample were taken out and placed in the compression device 30min before the first scan. We explored strain rates from 10-6 s-1 to 10-2 s-1 by vertically compressing 30 samples, up to a peak stress of 250 kPa and at a constant temperature of -18.5 °C. At high strain rates, only the initial and final 3D microstructures were scanned and simple radiographs were acquired during loading at a rate of 5 frames per second. At low strain rates, the 3D microstructure was regularly scanned during the loading. The obtained time series comprises one of the most-resolved (8.5 µm, 1h) and complete dataset on snow microstructure evolution near the ductile-to-brittle transition to date.

Results indicate a clear dependency of snow mechanical response on the strain rate. At strain rates larger than about 10-3 s-1, snow samples display heterogeneous deformations with the formation of compaction bands, while the stress-strain curve shows a serrated behavior. To relate this macroscopic behavior to micro-structural evolution, quantitative investigation of local density and specific surface area changes, as well as of bond network evolution, will be presented. These results should help identifying the micro-scale mechanisms at play during deformation of snow through both ductile and brittle range.
Mesoscale Eddy Kinetic Energy budgets and transfers between vertical modes in the Agulhas Current
Authors: Tedesco Pauline , Gula Jonathan , Penven Pierrick , Ménesguen Claire
Published: March 2022

Western boundary currents are hotspots of the mesoscale oceanic variability and of energy transfers, channeled by topography, toward smaller scales and eventually down to dissipation. Here, we assess the main mesoscale eddies energy sinks in the Agulhas Current region, with an emphasize on the different paths of energy toward smaller scales, from a regional numerical simulation. 

We derive an eddy kinetic energy (EKE) budget in the framework of the vertical modes. This comprehensive method accounts for energy transfers between energy reservoirs and vertical modes, including transfers channeled by topography and by a turbulent vertical cascade. 

The variability is dominated by mesoscale eddies (barotropic and 1st baroclinic modes) in the path of intense mean currents. Eddy-topography interactions result in a major mesoscale eddy energy sink (50 % of the total EKE sink). They represent energy transfers both toward higher baroclinic modes (27 % of the total EKE sink) and mean currents (23 % of the total EKE sink). Energy transfers toward higher baroclinic modes take different forms in the Northern Agulhas Current, where it corresponds to non-linear transfers to smaller vertical eddies on the slope (5 % of the total EKE sink), and in the Southern Agulhas Current, where it is dominated by a (linear) generation of internal-gravity waves over topography (22 % of the total EKE sink). The vertical turbulent cascade is significant in offshore regions, away from topography and intense mean currents. In these regions the direction of the turbulent vertical cascade is inverse - energy transferred from higher baroclinic modes toward mesoscale eddies - and it can locally amounts for most of the mesoscale eddies energy gain (up to 68 % of the local EKE source).

However, the Agulhas Current region remains a net source of mesoscale eddy energy due to the strong generation of eddies, modulated by the topography, especially in the Southern Agulhas Current. In the complex Agulhas Current system, which includes an intense mean oceanic current and mesoscale eddies field as well as strong topographic constraint and stratification gradients, the local generation of mesoscale eddies dominates the net EKE budget. It is in contrast with the paradigm of mesoscale eddies decay upon western boundaries, suggested as being due to topographically-channeled interactions triggering a direct energy cascade.
Data-driven modelling of soil moisture: mapping organic soils
Authors: Khamis Doran , Fry Matt , Cooper Hollie , Morrison Ross , Blyth Eleanor
Published: March 2022

Improving our understanding of soil moisture and hydraulics is crucial for flood prediction, smart agriculture, modelling nutrient and pollutant spread and evaluating the role of land as a sink or source of carbon and other greenhouse gases. State of the art land surface models rely on poorly-resolved soil textural information to parametrise arbitrarily layered soil models; soils rich in organic matter – key to understanding the role of the land in achieving net zero carbon – are not well modelled. Here, we build a predictive data-driven model of soil moisture using a neural network composed of transformer layers to process time series data from point-sensors (precipitation gauges and sensor-derived estimates of potential evaporation) and convolutional layers to process spatial atmospheric driving data and contextual information (topography, land cover and use, location and catchment behaviour of water bodies). We train the model using data from the COSMOS-UK sensor network and soil moisture satellite products and compare the outputs with JULES to investigate where and why the models diverge. Finally, we predict regions of high peat content and propose a way to combine theory with our data-driven approach to move beyond the sand-silt-clay modelling framework.
Structure of the Laplace operator, geometry of the Earth’s surface and successive approximations in the solution of the geodetic boundary value problem
Authors: Holota Petr , Nesvadba Otakar
Published: March 2022

The Laplace operator has a relatively simple structure in terms of spherical or ellipsoidal coordinates which are frequently used in geodesy. However, in treating the geodetic boundary value problem the physical surface of the Earth substantially differs from a sphere or an oblate ellipsoid of revolution, even if optimally approximated. Therefore, an alternative between the boundary complexity and the complexity of the coefficients of the Laplace partial differential equation governing the solution is discussed. The situation is more convenient in a system of general curvilinear coordinates such that the physical surface of the Earth (smoothed to a certain degree) is imbedded in the family of coordinate surfaces. The idea is close to concepts followed also in other branches of engineering and mathematical physics. A transformation of coordinates is applied. Subsequently, tensor calculus is used to express the Laplace operator in the system of new coordinates. The structure of the Laplacian is more complicated now, but in a sense it represents the topography of the physical surface of the Earth. Finally, the Green’s function method together with the method of successive approximations is used for the solution of the geodetic boundary value problem expressed in terms of the new coordinates. The structure of iteration steps is analyzed and where useful and possible, modified by means of integration by parts. The iteration steps and their convergence are discussed and interpreted, numerically and in terms of functional analyses.

 
Satellite Derived CH4 and NOx Emissions from the Oil and Gas Industry in the Permian Basin in the U.S.A.
Authors: Veefkind Pepijn , Serrano Calvo Raquel , Dix Barbara , Liu Mengyao , van der A Ronald , de Gouw Joost , Levelt Pieternel
Published: March 2022

The Permian basin is the largest oil and gas production region in the U.S.A. Because of the non-conventional exploration of the basin, the region is covered with hundreds of small production facilities. Observations from the surface and from aircrafts have shown that there are continuous emissions of amongst others CH4 and NOx. Although they come from the same facilities, the sources of CH4 and NOx differ: NOx is predominantly produced by engines and generators used for drilling and to run the facilities, whereas CH4 is produced from planned and accidental releases from the production, storage and transportation of oil and gas. The TROPOMI satellite instrument allows continuous monitoring of CH4 and NO2 and has confirmed the large contribution of the oil and gas industry to the CH4 and NO2 concentrations in the Permian basin.

Using the divergence method, we have derived emissions for both CH4 and NO2 from the TROPOMI data, with a high spatial resolution of better than 5x5 km2 for NO2 and better than 10x10 km2 for CH4. The results show that the Permian CH4 emissions in the basin are not dominated by a few large emission events, but are also impacted by many smaller releases across the basin. The basin can therefore be seen as a large area source that varies in space and time. Mitigation of these releases is challenging, rather than solving a few large leaks in a few facilities, the equipment and management of many small sites have to be improved to reduce emissions.

In this contribution we present results of the emission retrievals. Using CAMS model data, we show the potential of the divergence method and its sensitivity. Analyses will be presented of the TROPOMI derived emissions, showing the spatial variability of CH4 and NOx emissions over the region and their relation to the underlying oil and gas production and drilling activities.
Trapped remnant of the Tethyan realm: the influence of ancient tectonics on the present-day geodynamics of the eastern Mediterranean 
Authors: Granot Roi
Published: March 2022

The eastern Mediterranean Sea preserves crust that was trapped during the collision of Africa with Eurasia and the closure of the Neo-Tethyan Ocean. Thick sedimentary blanketing (10 to 15 km) complicates our ability to assess the nature of the crust, and therefore it has remained one of the least understood regions of the collision belt. In this presentation, I review recent marine geophysical observations (surface and deep-tow magnetics, high-resolution bathymetry and seismic reflection data) and discuss their geodynamic implications. The surface total field and vector magnetic anomalies from the Herodotus Basin reveal a sequence of long-wavelength NE-SW lineated anomalies that straddle the entire basin suggesting a deep two-dimensional magnetic source layer. The magnetic vector data indicate an abrupt transition from a 2D to a 3D magnetic structure along the eastern edge of the Herodotus Basin and west of the Eratosthenes Seamount, where a prominent gravity feature is found. These findings indicate that the Herodotus Basin preserves remnants of oceanic crust accreted along a mid-ocean ridge system that spread in an NW-SE direction. The African Plate's continuous northward and counterclockwise motion during the Paleozoic and Mesozoic allow predicting the crustal remanent magnetization directions, which dictate the shape of the present-day magnetic anomalies. The shape of the Herodotus anomalies best fit Carboniferous magnetization directions. The combination of surface and deep-tow magnetic data, as well as thermal and magnetic forward modeling, suggest that spreading was slow (~25 km/myr half spreading rates) and that the upper oceanic crust has been entirely demagnetized, probably due to the heating effect induced by the thick sedimentary coverage.

 

The stretched continental crust of the Levant Basin, found east of the Herodotus Basin, preserves a series of horsts and grabens that generally orient in an orthogonal direction relative to the spreading direction, suggesting that they may have formed concurrently with the initial opening of the Herodotus Basin. Earthquake data and long NW-SE bathymetric scars found within the northern edge of the Nile deep-sea fan suggest that an active fault belt transfers the motion from the Gulf of Suez toward the northern convergence boundaries. This fault belt is directed toward, and merges with, the continental-ocean boundary that straddles the eastern Herodotus Basin. This observation may indicate that the mechanical transition from the rather weak and stretched continental crust of the Levant to the relatively strong oceanic Herodotus crust has guided the location of the western boundary of the Sinai Microplate, formed during the Oligocene by the fragmentation of the African Plate.
Widespread And Unprecedented Phytoplankton Blooms Triggered By 2019–2020 Australian Wildfires
Authors: Llort Joan , Tang Weiyi , Weis Jakob , Perron Morgane , Basart Sara , Li Zuchuan , Sathyendranath Shubha , Jackson Thomas , Sanz Rodriguez Estrella , Proemse Bernadette , Bowie Andrew , Schallenberg Christina , Strutton Peter , Matear Richard , Cassar Nicolas
Published: March 2022

Droughts and climate-change-driven warming lead to more frequent and intense wildfires, arguably contributing to the severe 2019–2020 Australian wildfires. The environmental and ecological impacts of the fires include loss of habitats and the emission of substantial amounts of atmospheric aerosols. Aerosol emissions from wildfires can lead to the atmospheric transport of macronutrients and bio-essential trace metals such as nitrogen and iron, respectively. Previous works suggested that the oceanic deposition of wildfire aerosols can relieve nutrient limitations and, consequently, enhance marine productivity, but direct observations are lacking. Here we use satellite and autonomous biogeochemical Argo float data to evaluate the effect of 2019–2020 Australian wildfire aerosol deposition on phytoplankton productivity. We find widespread and long-lasting phytoplankton blooms in the Southern Ocean downwind of Australia. Aerosol samples originating from the Australian wildfires contained a high iron content, and atmospheric trajectories show that these aerosols were likely to be transported to the bloom regions, suggesting that the blooms resulted from the fertilization of the iron-limited waters of the Southern Ocean.
Melt volume at Atlantic volcanic rifted margins controlled by depth-dependent extension and mantle temperature
Authors: Lu Gang , Huismans Ritske
Published: March 2022

Breakup volcanism along rifted passive margins is highly variable in time and space. The factors controlling magmatic activity during continental rifting and breakup are not resolved and controversial. Here we use numerical models to investigate melt generation at rifted margins with contrasting rifting styles corresponding to those observed in natural systems. Our results demonstrate a surprising correlation of enhanced magmatism with margin width. This relationship is explained by depth-dependent extension, during which the lithospheric mantle ruptures earlier than the crust, and is confirmed by a semi-analytical prediction of melt volume over margin width. The results presented here show that the effect of increased mantle temperature at wide volcanic margins is likely over-estimated, and demonstrate that the large volumes of magmatism at volcanic rifted margin can be explained by depth-dependent extension and very moderate excess mantle potential temperature in the order of 50-80 °C, significantly smaller than previously suggested.
The Polar Regions in the Earth System (PolarRES) project
Authors: Mooney Priscilla
Published: March 2022

Polar climates in a global context remain poorly understood, as does the interactions between the different components of the Polar climate system. These knowledge gaps are leading to large uncertainties in climate change projections for the Polar regions, which hampers mitigation and adaptation efforts. PolarRES, a new project funded by the European Commission under the Horizon 2020 programme, will address these knowledge gaps in the coming years. The PolarRES consortium consists of more than 50 researchers from 21 different institutions from around the world and began in September 2021. The project will zoom into the climate of both Polar regions at unprecedented resolutions with state-of-the-art regional climate models (RCMs) that will be blended with a comprehensive range of existing and novel ground-based observations (for example from the Year Of Polar Prediction (YOPP) and the MOSAiC expedition) and satellite data  (e.g. ESA Earth Observation Programme) to close knowledge gaps on 1) the atmosphere-ocean-sea ice coupled system, 2) the influence of future changes in the global circulation system on the polar climate, and 3) the influence of the polar regions on the global climate system. In doing so, PolarRES will provide novel, more confident, regional climate projections of the polar regions for impact assessments. This work is being undertaken in a multidisciplinary framework that brings together climate and impact modelers to ensure that climate change projections for both Polar regions are impact relevant. This talk will introduce the PolarRES project (https://polarres.eu), progress to date, and the innovative approaches that will be used in the project.
Coronal Magnetic Field Extrapolation Using a Specific Family of Analytical 3D Magnetohydrostatic Equilibria — Practical Aspects
Authors: Nadol Lilli , Neukirch Thomas
Published: March 2022

With current observational methods it is not possible to determine the magnetic field in the solar corona accurately. Therefore, coronal magnetic field models have to rely on extrapolation methods using photospheric magnetograms as boundary conditions. In recent years, due to the increased resolution of observations and the need to resolve non-force-free lower regions of the solar atmosphere, there have been increased efforts to use magnetohydrostatic (MHS) field models instead of force-free extrapolation methods. Although numerical methods to calculate MHS solutions can deal with non-linear problems and hence provide more accurate models, analytical three-dimensional MHS equilibria can also be used as a numerically relatively “cheap” complementary method.

 

We discuss a family of analytical MHS equilibria that allows for a transition from a non-force-free region to a force-free region. The solution involves hypergeometric functions and while routines for the calculation of these are available, this can affect both the speed and the numerical accuracy of the calculations. We therefore look into the asymptotic behaviour of this solution in order to numerically approximate it through exponential functions aiming to improve the numerical efficiency. We present an illustrative example by comparing field line profiles, density and pressure differences between the exact solutions, the asymptotic solution and a hybrid model where the use of the hypergeometric function is restricted to an area around the transitional region between the non-force-free and the force-free domain.
The impact of charged aerosols on cloud-condensation nuclei formation with GEOS-Chem
Authors: Riádigos Irma , Marais Eloise , Pierce Jeffrey , Pérez Muñuzuri Vicente
Published: March 2022

The ionization caused by Cosmic Rays (CR) in the atmosphere can influence the growth of aerosols that will modify the density of cloud-condensation nuclei (CCN). In fact, the flux of CR in the atmosphere has been reported to correlate with cloud and aerosol properties. Several mechanisms have been proposed and tested to explain this effect, leading to the conclusion that the induced effects were minor. Still, these studies did not completely disprove the link between CR and clouds (i.e., climate). Since then, different mechanisms that could be relevant to aerosol growth have been proposed. One of them is the diffusion-charging mechanism by which aerosols acquire charges by diffusion of atmospheric ions onto their surface.  Charging and aerosol coagulation can influence each other and impact the particle charge and size distributions in the atmosphere. Previous works have developed approaches to explicitly solve all the equations governing charge and size distribution in particles. However, since aerosols can acquire a large number of charges, the number of equations to solve would be immense and very computationally expensive. Fortunately, other approaches have also been developed that allow diffusion charging to be implemented more efficiently. In this work, we use for the very first time a global chemistry transport model (GEOS-Chem) to implement the effects of diffusion charging from CR on the microphysical development of aerosols following those approaches. We compare the variations of CCN concentrations between the solar maximum and the solar minimum (i.e., different atmospheric ionization scenarios) to test the sensitivity of the effect. Results indicate that the influence of diffusion charging can be relevant under several atmospheric conditions. In such cases, the change in the concentrations of CCN between the solar maximum (high cosmic-ray flux) and the solar minimum (low cosmic-ray flux) is found to be larger than 1%, which may become relevant for cloud formation. 
Conceptualizing feedbacks between climate services and adaptation actions across various European contexts.
Authors: Biella Riccardo , Di Baldassarre Giuliano , Brandimarte Luigia , Mazzoleni Maurizio
Published: March 2022

The success of climate adaptation actions relies on the availability and quality of information, especially in climate-sensitive sectors such as tourism, agriculture, and river management. Over the years, researchers have highlighted how climate services providing such key information should focus on end-user needs to bridge the usefulness-usability gap. Thus, overcoming this dichotomy will enable the effective use of climate services in adaptation initiatives, especially at the local scale. In this study, we present the basis for a conceptual framework identifying the balancing and reinforcing feedbacks in a coupled human-climate system, with a focus on hydrological risks, i.e. floods and droughts. The analysis is based on system dynamics conceptualization and builds upon data from various living labs (i.e. case studies) across Europe. The framework is presented as a causal-loop diagram and emerging behaviors of the system are described using system archetypes. The proposed framework highlights the importance of understanding feedbacks between climate information and adaptation options when designing user-centered climate services. Moreover, it sheds a light on usefulness of system dynamics as a tool for informing the planning of effective adaptation actions while building resilience.

 
Data Driven Approaches for Climate Predictability
Authors: Nadiga Balasubramanya
Published: March 2022

Reduced-order dynamical models play a central role in developing our understanding of predictability of climate. In this context, the Linear Inverse Modeling (LIM) approach (closely related to Dynamic Mode Decomposition DMD), by helping capture a few essential interactions between dynamical components of the full system, has proven valuable in being able to give insights into the dynamical behavior of the full system. While nonlinear extensions of the LIM approach have been attempted none have gained widespread acceptance. We demonstrate that Reservoir Computing (RC), a form of machine learning suited for learning in the context of chaotic dynamics, by exploiting the phenomenon of generalized synchronization, provides an alternative nonlinear approach that comprehensively outperforms the LIM approach.  Additionally, the potential of the RC approach to capture the structure of the climatological attractor and to continue the evolution of the system on the attractor in a realistic fashion long after the ensemble average has stopped tracking the reference trajectory is highlighted. Finally, other dynamical systems based methods and probabilistic deep learning methods are considered and a broader perspective on the use of data-driven methods in understanding climate predictability is offered
Direct Numerical Simulation of the Aerodynamically Rough Atmospheric Boundary Layer – Implementation of an Immersed Boundary Method for Turbulent Ekman Flow
Authors: Kostelecky Jonathan , Ansorge Cedrick
Published: March 2022

Direct numerical simulation (DNS) of the atmospheric boundary layer (ABL) is becoming more and more popular for its conceptual simplicity and increasing degree of realism: domain sizes and simulation durations can be attained that allow for extrapolation of results to the geophysical limit. Geophysical flows predominantly occur over rough surfaces, which significantly affects drag, mixing and transport properties of the flow. For such flows, a method is needed that allows one to impose the intricate mechanical boundary condition resulting from a rough wall, while maintaining the efficient and tuned numerical methods for Cartesian meshes. This is achieved by an immersed boundary method (IBM), where three-dimensional roughness elements are fully resolved at the bottom wall of the simulation domain. Based on the work by Laizet and Lamballais (J. Comp. Phys 2009, Vol 228, p.5989-6015), we develop an IBM for efficient use in a stratified environment. First, a spline interpolation method is used to reduce oscillations in the artificial part of the velocity field. Second, a partially staggered arrangement is introduced to avoid spurious pressure oscillations, as is the case with collocated grids for pressure and velocity. Third, the thermal boundary conditions need to be adjusted to account for background gradients across the height of roughness elements. Based on this implementation, the effect of roughness is investigated in terms of fully resolved three-dimensional roughness elements located on the bottom wall of the simulation domain for neutral and stably stratified turbulent Ekman layer flows.

* This work is funded by the ERC Starting Grant ”Turbulence-Resolving Approaches of the Intermittently Turbulent Atmospheric Boundary Layer [trainABL]” of the European Research Council (funding ID 851347).
Climate literacy for professionals in the Netherlands
Authors: Bessembinder Janette , Kluck Jeroen , Niederer Sabine , Renes Reint Jan
Published: March 2022

Professionals in sectors such as urban planning, energy transition, health, need knowledge about climate change for e.g. designing tunnels, urban planning, risk assessments related to climate change, giving policy advice about adaptation measures. The required climate data and information is often not easy to find, needs to be processed, or there is so much climate data available that it is difficult to determine what should be used in a specific situation. In addition, these professionals often have contact with administrators and citizens who ask them questions about climate change, why certain adaptation measures are taken, etc. However, there are a lot of misunderstandings about climate and climate change and there is a lot of polarization.
Both the Dutch Meteorological Institute (KNMI) and the Amsterdam University of Applied Sciences (HvA) have a lot of contact with professionals working on climate adaptation and mitigation and they both recognize that professionals need more tailoring of climate data and, at the same time, they need help with the communication about climate change. Based on the experiences of the HvA and KNMI in recent years, they decided in the autumn of 2021 to combine their complementary expertises into a lectorate “Climate literacy” to develop new knowledge for professionals: 

about climate data and climate change for more effective use in design, risk assessment, policy advice and to be able to make well-informed decisions. This concerns technical knowledge about access to climate data, good use of climate data and climate scenarios, dealing with uncertainties, better linking of climate data and information to the purpose of the sector (i.e. based on knowledge of the technical systems) and decision support.

to effectively increase the “climate literacy” of citizens and administrators (tools, interventions, design methods, communication strategies, policy-making), so they  can act well informed in situations related to climate change. For professional users, reliable and easy to understand climate information is also necessary to create support among stakeholders and the general public. For this, it is necessary to connect with how people experience the environment and to relate causes, consequences and action perspectives to themselves.

During the presentation we will elaborate on why it is important to have a combined focus on the tailoring of climate data and communication for professionals, our experiences in the Netherlands and the ideas for research within this lectorate.
An adaptive-triangular fully coupled 3D ice-sheet–sea-level model
Authors: Bernales Jorjo , Berends Tijn , van de Wal Roderik
Published: March 2022

Regional sea-level change and the deformation of the solid Earth can lead to important feedbacks on the long- and short-term evolution and stability of ice sheets. A rigorous manner of accounting for these feedbacks in model-based ice-sheet reconstructions and projections, is to establish a two-way coupling between an ice-sheet and a sea-level model. However, the individual requirements of each of these two components — such as a global, long ice sheet load history or a high ice-model resolution over critical sectors of an ice sheet — are at present not easy to combine in terms of computational feasibility. Here, we present a coupling between the ice-sheet model UFEMISM, which solves a range of approximations of the stress balance on a dynamically adaptive irregular triangular mesh, and the gravitationally self-consistent sea-level model SELEN, which incorporates the glacial isostatic adjustment for a radially symmetric, viscoelastic and rotating Earth, including coastline migration. We show global simulations over glacial cycles, including the North American, Eurasian, Greenland, and Antarctic ice sheets, and compare its performance and results against commonly used alternatives.
Future increase in Arctic moisture transport dominated by midlatitude CO2 forcing
Authors: Dunn-Sigouin Etienne , Li Camille , Kushner Paul
Published: March 2022

Northward transport of moisture is a key driver of Arctic warming and is projected to increase in the future. However, the importance of local versus remote forcing, and the mechanisms through which they impact the Arctic, are unclear. Here, we determine the causes of increased Arctic moisture transport using climate model simulations in which idealised CO2 forcing is prescribed in distinct latitudinal regions. The sum of the regional responses reproduce the response to global forcing and resembles the future change seen in state-of-the-art climate model projections. Midlatitude forcing dominates future changes in Arctic moisture transport, while tropical and polar forcing play a secondary role. Increases in zonal-mean Arctic moisture transport result mostly from changes in transient eddy transport and scale with increased water vapour. Similar increases are found in an analogous set of simulations without the presence of land and orography, suggesting climatological zonal asymmetries, such as stationary eddies and gradients of sea-surface temperature, do not set the first-order zonal-mean response. In contrast, zonal changes in Arctic moisture transport are dominated by changes in stationary eddy transport, where both increased water vapour and meridional wind changes are important. Thus, the future increase in Arctic moisture transport depends primarily on dynamic and thermodynamic processes forced in midlatitudes.
Imaging of hydraulic conductivity from seismic and electrical data in a joint inversion framework
Authors: Steiner Matthias , Pavlin Lovrenc , Katona Timea , Wagner Florian M. , Roser Nathalie , Strauss Peter , Blöschl Günter , Flores Orozco Adrian
Published: March 2022

The hydraulic conductivity (K) is a relevant parameter in soil sciences as it is critical, e.g., for hydrological modeling or the characterization of groundwater flow and atmosphere-soil interactions. Field investigations allow for the direct assessment of K, yet the number and distribution of the sampling points limit the spatial resolution. To assess the spatial variability of K at the field scale, pedotransfer functions (PTFs) have been developed, which estimate K from soil parameters such as soil texture or bulk density. On the other hand, geophysical methods have also revealed their potential to quantify K in laboratory investigations, yet investigations at the field scale are still rare. In this study, we investigate the estimation of K through the simultaneous inversion of seismic and electrical data in an imaging framework. We use an open-source joint inversion framework, and adapt the underlying petrophysical model to take into account the (electrical) surface conductivity during parameter estimation. In particular, we invert resistivity data collected at a low and a high frequency, considering that the associated difference accounts for the (electrical) surface conductivity based on the frequency dependence of the observed electrical response. Accordingly, our joint inversion scheme solves, among other parameters, for water content, cation exchange capacity, polarization and porosity, which we use to quantify K through different models developed from laboratory investigations. Moreover, we investigate the possibility to enhance the quantification of K by adapting the joint inversion scheme to solve directly for the parameters required by the employed models. We illustrate our approach based on data collected at the Hydrological Open Air Laboratory (HOAL), a thoroughly investigated and monitored catchment located in Petzenkirchen (Lower Austria). We use available information about soil properties to calibrate our joint inversion scheme and evaluate the resolved K models based on K values obtained through direct investigations or the use of PTFs, respectively. Our approach contributes to the field-scale estimation of process-relevant subsurface properties at high spatial resolution by means of non-invasive geophysical imaging techniques – a key objective of the hydrogeophysical discipline.
Deep-Water Agglutinated Foraminifera from the Contessa Highway Section, Umbria-Marche Basin, Italy: Assemblage turnover at the Cretaceous/Paleogene Boundary
Authors: Kaminski Michael , Hikmahtiar Syouma , Cetean Claudia
Published: March 2022

Deep-water agglutinated foraminifera (DWAF) are investigated from the lower Paleocene of the Contessa Highway section in the Umbria-Marche Basin in Italy. In the lowermost meter of the Paleocene, corresponding the P0, Pa, and lowermost P1 planktonic foraminifera zones, a total of 46 species of DWAF are observed. A comparison with the uppermost Maastrichtian DWAF assemblages documented by Cetean (2009) yields a combined total of 94 DWAF species over the Cretaceous/Paleogene boundary interval at Contessa Highway. Of these, 49 species are listed as extinction taxa, nine are survivor taxa, 19 are Lazarus taxa, and 17 taxa display first occurrences in the Paleocene.

The record of DWAF in the Contessa Highway section displays a moderate decrease in diversity across the K/Pg boundary, followed by a gradual recovery in the first meter of the Paleocene. The lower Paleocene record is characterized by blooms of opportunistic species belonging to the genera Reophax, Subreophax, Repmanina, and Spiroplectinella. The K/Pg boundary interval records a major change in the proportions of DWAF morphogroups, from a suspension-feeding community in the Maastrichtian to one dominated by epifaunal detritivores in the lower Paleocene, reflecting a fundamental change in the nature of marine primary productivity following the bollide impact. 