bluuebunny/crossref_metadata_2025 huggingface dataset:
Towards Open and FAIR Hydrological Modelling with eWaterCycle
Authors: Drost Niels , Aerts Jerom P.M. , Alidoost Fakhereh , Andela Bouwe , Camphuijsen Jaro , van de Giesen Nick , Hut Rolf , Hutton Eric , Kalverla Peter , van den Oord Gijs , Pelupessy Inti , Smeets Stef , Verhoeven Stefan , van Werkhoven Ben
Published: March 2021

The eWaterCycle platform (https://www.ewatercycle.org/) is a fully Open Source system designed explicitly to advance the state of Open and FAIR Hydrological modelling. While working with Hydrologists to create a fully Open and FAIR comparison study, we noticed that many ad-hoc tools and scripts are used to create input (forcing, parameters) for a hydrological model from the source datasets such as climate reanalysis and land-use data. To make this part of the modelling process better reproducible and more transparent we have created a common forcing input processing pipeline based on an existing climate model analysis tool: ESMValTool (https://www.esmvaltool.org/). 

Using ESMValTool, the eWaterCycle platform can perform commonly required preprocessing steps such as cropping, re-gridding, and variable derivation in a standardized manner. If needed, it also allows for custom steps for a hydrological model. Our pre-processing pipeline directly supports commonly used datasets such as ERA-5, ERA-Interim, and CMIP climate model data, and creates ready-to-run forcing data for a number of Hydrological models.

Besides creating forcing data, the eWaterCycle platform allows scientists to run Hydrological models in a standardized way using Jupyter notebooks, wrapping the models inside a container environment, and interfacing to these using BMI, the Basic Model Interface (https://bmi.readthedocs.io/). The container environment (based on Docker) stores the entire software stack, including the operating system and libraries, in such a way that a model run can be reproduced using an identical software environment on any other computer.

The reproducible processing of forcing and a reproducible software environment are important steps towards our goal of fully reproducible, Open, and FAIR Hydrological modelling. Ultimately, we hope to make it possible to fully reproduce a hydrological model experiment from data pre-processing to analysis, using only a few clicks.
Complex interactions of in-stream DOM and nutrient spiralling unravelled by Bayesian regression analysis
Authors: Pucher Matthias , Flödl Peter , Graeber Daniel , Felsenstein Klaus , Hein Thomas , Weigelhofer Gabriele
Published: March 2021

The carbon cycle in aquatic environments is of high interest because of its effects on water quality and greenhouse gas production as well as its alteration through anthropogenic activities with unknown outcomes. Uptake and release of dissolved organic matter (DOM) compounds is depending on the molecular structure and is strongly linked to N and P dynamics. Current research has not fully revealed the complex patterns behind.

To investigate the interactions between DOM components, we performed ten plateau addition experiments with different, realistic, complex DOM leachates (cow dung, pig dung, corn, leaves and nettles) in a small stream. The DOM quality was determined by fluorescence measurements and parallel factor (PARAFAC) decomposition and the nutrient concentrations were measured at eleven consecutive points in the stream at plateau conditions. The hydrological transport processes were incorporated by using the results of a 1-D hydrodynamic model.

The nutrient spiralling concept and its application in nutrient dynamics is a valuable basis for the analysis of our data. However, we could not find a data analysis approach, that suited the nature of our questions and data. Based on previously observed nutrient uptake models, we extended the nutrient spiralling concept by additional non-linear terms to analyse interactions between different DOM components.

We developed the “Interactions in Nutrient Spirals using BayesIan REgression (INSBIRE)” approach to analyse DOM uptake and retention mechanism. This approach can disentangle complex and interacting biotic and abiotic drivers in nutrient uptake metrics, show their variability and quantify their error distribution. We successfully used INSBIRE to show DOM-compound-specific interactions and draw conclusions from the data of our experiment. The applicability of INSBIRE has still to be tested in other studies, but we see a high potential not only in DOM dynamics but any kind of solute dynamics where interactions are crucial.
Towards Application of StorAge Selection Functions in Large-Scale Catchments with Heterogeneous Travel Times and Subsurface Reactivity
Authors: Nguyen Tam , Sarrazin Fanny , Lutz Stefanie R. , Kumar Rohini , Musolff Andreas , Fleckenstein Jan H.
Published: March 2021

StorAge Selection (SAS) functions describe how a catchment selectively removes water and solute of different ages via discharge, thus controlling transit time distributions (TTDs) and solute composition of discharge. Previous studies have successfully applied SAS functions in a spatially lumped approach to capture catchment-scale transport phenomena of (non-)conservative solutes. The lumped approach assumes that water and solutes within a water parcel of a specific age are well-mixed. While this assumption does not cause any changes in the age of water, the spatial heterogeneity of solute concentrations within this water parcel is lost. In addition, in large catchments, headwater sub-catchments and lowland sub-catchments could behave in different ways, e.g., the transit times (TTs) and reaction rates between headwater and lowland sub-catchment could be of different magnitudes. This, in turn, might not be sufficiently represented in a lumped approach of SAS functions.

In this study, we applied the mHM-SAS model (Nguyen et al., 2020) with a semi-distributed approach of SAS functions. The nested mesoscale catchment (Selke catchment, Germany) with heterogeneous land use management practices, TTs, and subsurface reactivity was used as a case study. In addition to spatial variability, a functional relationship between the parameters of the SAS functions and storage dynamics was introduced to capture temporal dynamics of the selection preference for discharge. High frequency instream nitrate data were used to validate the proposed approach. Results show that the proposed approach can well represent nitrate export at both sub-catchment and catchment levels. The model reveals that catchment nitrate export is controlled by (1) the headwater sub-catchment with fast TTs and a high denitrification rate, and (2) the lowland sub-catchment with longer TTs and a low denitrification rate. In general, the proposed approach serves as a promising tool for understanding the interplay of transport and reaction times between different sub-catchments, which controls nitrate export in a mesoscale heterogeneous catchment.

Nguyen, T. V., Kumar, R., Lutz, S. R., Musolff, A., Yang, J., & Fleckenstein, J. H. (2020). Modeling Nitrate Export from a Mesoscale Catchment Using StorAge Selection Functions. Water Resources Research, 56, e2020WR028490
CFOSAT wave spectra joining the family of L2P-L3 CMEMS Wave products!
Authors: Ollivier Annabelle , Dibarboure Gerald , Husson Romain , Goimard Gael , Hauser Daniele , Tourain Cedric , Aouf Lotfi
Published: March 2021

SWIM CFOSAT innovative instrument has already shown its reliability and data quality interest through several publications since its launch in end 2018. Its nadir data are delivered to CMEMS since July 2019 in a L2P/L3. Similarly to other nadir missions AltiKa, Jason3, HY2B, S3…,  these easy to use products are based on a selection of valid data from quality criteria, and bias alignment to buoys networks. They are provided in near real time (3h) and with a 1Hz sampling.

In 2021, the CFOSAT project team is happy to provide to CMEMS, in addition to the mission full products, a  user friendly product, with preselected valid datasets of directional wave spectra and related parameters, and additional information directly derived from the calval expertises upstream. Thanks to it, non expert users should be able to have a simple access to this new product and easy compare it to SAR Wavemode L3 products already in the CMEMS catalogue.

This presentation is a user friendly approach to describe the added value, the future improvements planned and the potential of such product for non experts applications.
Does a Staggered Scheme Pay Off on Large-scale Hydraulic-mechanical Simulations?
Authors: Kern Dominik , Magri Fabien , Malkovsky Victor , Nagel Thomas
Published: March 2021

From previous studies it is evident that decoupled simulations lack the ability to capture certain coupled effects, such as the Noordbergum effect or the Mandel-Cryer effect in a hydraulic-mechanical context. Thus, for detailed simulations of geotechnical or geological system, coupled simulations are usually chosen. For example, thermal-hydraulic-mechanical (THM) coupled systems, and even chemical and biological couplings (THMCB), are considered in simulations used to assess barrier integrity over long time spans in the context of geological waste disposal.

This paper is restricted to coupled hydraulic-mechanical (HM) systems. A monolithic approach is both stable and accurate for strongly coupled systems. However, as site-scale models of geological disposal facilities are also large in spatial dimensions, it is worth to investigate how staggered methods may cut down the computational costs. The fixed-stress split appears to be a promising approach for staggered schemes in terms of stability, consistency, accuracy, and efficiency.

While adding another iteration level in comparison to monolithic schemes, staggered schemes allow for lower-order approximation spaces, whereas monolithic schemes require Taylor-Hood elements resulting in a larger number of degrees of freedom per element. Both coupling schemes are implemented in the the open-source finite-element (FE) software OpenGeoSys and used to simulate a large-scale model, which is oriented towards a real site in planning in Russia. Simulation results are compared in terms of accuracy, coupling effects and performance.
The interplay among analytical method, preprocessing, and modeling on soil organic carbon Vis-NIR-SWIR predictions
Authors: Zborowski Horst-Heinen Taciara , Diniz Dalmolin Ricardo Simão , Samuel-Rosa Alessandro , Grunwald Sabine
Published: March 2021

The relationship between visible-near-infrared (Vis-NIR-SWIR) spectra and soil organic carbon (SOC) and the effects of preprocessing techniques on SOC predictive models have been shown in several studies. However, little attention has been given to the effect of analytical methods used to produce the SOC data used to calibrate those models. The predictive performance of Vis-NIR spectral models depends not only on the preprocessing technique and machine learning method but also on the analytical method employed to produce the SOC data. Our hypothesis is that some combinations of preprocessing and models may be more sensitive to laboratory (measurement) error than others. To test this hypothesis, we evaluated the leave-one-out cross-validation performance of three predictive models (Random Forest (RF), Cubist, and Partial Least Square Regression (PLSR)) calibrated using SOC data produced via three analytical methods (dry combustion (DC) and wet combustion with quantification by titration (WCt) and colorimetry (WCc)) and three Vis-NIR spectra preprocessing techniques (smoothing (SMO), continuum removal (CRR), and Savitzky-Golay first derivative (SGD)). The prediction performance varied among the models. DC and WCt provided a higher correlation between SOC and spectra than WCc, and thus, resulted in higher accuracy. The Cubist+CRR was ranked the best performing model, with an average of R2 = 0.81 and RMSE = 0.81% among analytical methods. Cubist+CRR also minimized the accuracy differences resulting from SOC analytical methods employed. The RF model had low accuracy and was unable to explain more than 46% of the variance. Overall, the analytical method significantly affects SOC predictions, and its impact may be larger than the preprocessing. 
Triple isotopic composition of oxygen in the atmospheric dioxygen to reconstruct the dynamic of global biosphere productivity in the past from measurements in biological chambers
Authors: Paul Clémence , Farradèche Morgane , Piel Clément , Sauze Joana , Romanini Daniele , Pasquier Nicolas , Prié Frédéric , Jacob Roxanne , Jossoud Olivier , Dapoigny Arnaud , Devidal Sébastien , Milcu Alexandru , Landais Amaëlle
Published: March 2021

High precision measurements of triple isotopic composition of oxygen in the air trapped in ice cores is a useful tool to infer the global gross biosphere productivity in the past. The isotopic composition of oxygen is influenced by many physical, chemical and biological processes during consumption and production of oxygen by the oceanic and terrestrial biosphere. For an accurate quantification of the past biosphere productivity, it is thus important to determine the different fractionation processes occurring in the biosphere during respiration and photosynthesis processes.

We present here quantification of fractionation coefficients associated with δ180 and the D170 of 02 during respiration and photosynthesis within the terrestrial biosphere. The experimental set-up relies on closed biological chambers in which all the environmental parameters are controlled and measured. Triple isotopic composition of oxygen is regularly measured through sampling of small aliquots at a low frequency (4 h to 4 days). Seven 2-month long experiments were performed in order to check the reproducibility of our set-up and quantify uncertainty on the determination of the fractionation coefficients.

In order to improve our set-up for future experiments using different plants, we also present perspectives for a continuous measurement of the isotopic composition of oxygen using optical spectroscopy (Optical Feedback Cavity Enhanced Absorption Spectroscopy (OF-CEAS) technique). This instrument is currently being characterized and we will present its current performances.

Triple isotopic composition of oxygen in the atmospheric dioxygen to reconstruct the dynamic of global biosphere productivity in the past from measurements in biological chambers.
Interactive 3-D visual analysis of ERA 5 data: improving diagnostic indices for Marine Cold Air Outbreaks
Authors: Meyer Marcel , Polkova Iuliia , Rautenhaus Marc
Published: March 2021

We present the application of interactive 3-D visual analysis techniques using the open-source meteorological visualization framework Met.3D [1] for investigating ERA5 reanalysis data. Our focus lies on inspecting atmospheric conditions favoring the development of extreme weather events in the Arctic. Marine Cold Air Outbreaks (MCAOs) and Polar Lows (PLs) are analyzed with the aim of improving diagnostic indices for capturing extreme weather events in seasonal and climatological assessments. We adopt an integrated workflow starting with the interactive visual exploration of single MCAO and PL events, using an extended version of Met.3D, followed by the design and testing of new diagnostic indices in a climatological assessment. Our interactive visual exploration provides insights into the complex 3-D shape and dynamics of MCAOs and PLs. For instance, we reveal a slow wind eye of a PL that extends from the surface up into the stratosphere. Motivated by the interactive visual analysis of single cases of MCAOs, we design new diagnostic indices, which address shortcomings of previously used indices, by capturing the vertical extent of the lower-level static instability induced by MCAOs. The new indices are tested by comparison with observed PLs in the Barents and the Nordic Seas (as reported in the STARS data set). Results show that the new MCAO index introduced here has an important advantage compared with previously used MCAO indices: it is more successful in indicating the times and locations of PLs. We thus propose the new index for further analyses in seasonal climate predictions and climatological studies. The methods for interactive 3-D visual data analysis presented here are made freely available for public use as part of the open-source tool Met.3D. We thereby provide a generic tool that can be used for investigating atmospheric processes in ERA5 data by means of interactive 3-D visual data analysis. Met.3D can be used, for example, during an initial explorative phase of scientific workflows, as a complement to standard 2-D plots, and for detailed meteorological case-analyses in 3-D.

[1] http://met3d.wavestoweather.de, https://collaboration.cen.uni-hamburg.de/display/Met3D/
Waves at the edge of space revealed by noctilucent cloud observations using camera and lidar
Authors: Baumgarten Gerd , Conte J. Federico , Fiedler Jens , Gerding Michael , Lübken Franz-Josef
Published: March 2021

Noctilucent clouds (NLC) exist at an altitude of about 83 km during the summer season at middle and polar latitudes. They consist of icy particles that exist in the polar summer mesopause region where the atmosphere is about 100 K colder than expected from pure radiative forcing. Dynamical effects, for example the dissipation of gravity waves, play an important role in the global circulation finally leading to the cold summer mesopause region. Ever since the first reports on the occurrence of NLC in 1885 the observers noticed distinct structures in the clouds that are most often wave-like. However at times the wave field becomes seemingly chaotic.

State of the art lidar and camera observations of NLC allow studying small-scale structures of tens of meters in the vertical and horizontal direction. Given a high time resolution (about one second), the development of these structures is measured on temporal scales spanning the range from inertia gravity waves to acoustic gravity waves. We will show observations with the RMR-lidars at ALOMAR (Northern Norway at 69°N) and Kühlungsborn (54°N) as well as cameras located nearby these stations. Using these combined observations we study waves and their transition to turbulence.
Quantifying co-benefits and potential disbenefits of NBS for Disaster Risk Reduction: a practical framework for ex-ante assessment
Authors: Ommer Joy , Bucchignani Edoardo , Leo Laura S. , Kalas Milan , Vranić Saša , Debele Sisay , Kumar Prashant , Cloke Hannah L. , Di Sabatino Silvana
Published: March 2021

Nature-based solutions are increasingly implemented to tackle disaster risk reduction and climate change adaptation. Their rising popularity over grey solutions is partially explained by their number of additional benefits (so called co-benefits) for the socio-ecological system (SES). Frameworks are available to monitor and assess co-benefits, however, these frameworks are lacking clear guidance and ex-ante quantification of co-benefits and potential disbenefits of NBS. Another limitation is the accessibility and quality (representativeness) of data for computing indicators, especially, going towards larger scales (regional, pan-European). To develop a comprehensive framework and method for assessing and estimating possible side effects in advance, this paper aligns to existing frameworks but goes beyond those by providing practical guidance on data sourcing (including possible proxy variables) and quantification of both co-benefits and disbenefits. The resulting framework will support decision-making on area specific suitability of NBS for disaster risk reduction. Furthermore, it will enhance the planners’ knowledge and understanding of linked processes which can lead to potential positive and negative side effects; thus, this guidance will build a base for selecting suitable locations and NBS interventions.
Ectomycorrhizal fungal composition and function predict tree growth across Europe 
Authors: Anthony Mark , Crowther Thomas , van der Linde Sietse , Suz Laura , Bidartondo Martin , Cox Filipa , Schaub Marcus , Rautio Pasi , Ferretti Marco , Vesterdal Lars , Devos Bruno , Averill Colin
Published: March 2021

Ectomycorrhizal fungi are central members of the forest fungal community, forming symbiosis with most trees in temperate and boreal forests, enhancing plant access to limiting soil nutrients. Decades of greenhouse studies have shown that specific mycorrhizal fungi enhance tree seedlings growth and nutrient uptake rates, and that these effects are sustained when seedlings are out-planted into regenerating forests. Whether these relationships scale up to affect the growth of mature trees and entire forests harboring diverse fungal communities remains unknown. In this study, we combined a continental set of European forest inventory data from the ICP forest network with molecular ectomycorrhizal fungal community surveys to identify features of the mycorrhizal mycobiome linked to forest productivity. We found that ectomycorrhizal fungal community composition was a key predictor of tree growth, and this effect was robust to statistically accounting for climate, nitrogen deposition, soil inorganic nitrogen availability, soil pH, and forest stand characteristics. Furthermore, ectomycorrhizal fungi with greater genomic investment in energy production and inorganic nitrogen metabolism, but lower investment in organic nitrogen acquisition, were linked to faster tree growth. Lastly, we sampled soils from fast and slow growing forests and introduced their microbiomes into a sterilized growth medium to experimentally isolate microbiome effects on tree development. Consistent with our observational analysis, tree seedling growth was accelerated when inoculated with microbiomes from fast vs. slow growing forests.  By linking molecular community surveys and long-term forest inventory data in the field, and then pairing this with a microbiome manipulation study under controlled conditions, this work demonstrates an emerging link between the forest microbiome and dominant European tree growth rates.
Discontinuity analysis and evolution of magnetic switchbacks
Authors: Akhavan-Tafti Mojtaba , Kasper Justin , Huang Jia , Bale Stuart
Published: March 2021

Magnetic switchbacks are Alfvénic structures characterized as intervals of intermittent reversals in the radial componentof magnetic field. Switchbacks comprise of magnetic spikes preceded/succeeded by quiet, pristine solar wind. Determining switch-back generation and evolution mechanisms will further our understanding of the global circulation and transportation of Sun’s openmagnetic flux. Here, we investigate switchback transition regions using measurements from fields and plasma suites aboard the Parker SolarProbe (PSP). Minimum variance analysis (MVA) is applied on switchback transition region magnetic signatures. Discontinuity analysesare performed on 273 switchback transition regions with robust MVA solutions. Our results indicate that switchbacks are rotational discontinuities (RD) in 214 (or 78%) of the cases. 21% of the switchbacktransition regions are categorized as "either" discontinuity (ED), defined as small relative changes in both magnitude and the normalcomponent of magnetic field. RD-to-ED event count is found to reduce with increasing distance from the Sun. On average, plasmabeta falls by −28% across RD-type switchback transition regions and magnetic shear angle is 60 [deg], therefore making switchbacktransition regions theoretically favorable to local magnetic reconnection. The evolution of switchbacks away from the Sun may involve increasing mass flux across RD-type switchback transition regions. The evolution mechanism(s) remain to be discovered. Our results indicate negligible magnetic curvature across switchback transition regions which may inhibit local magnetic reconnection.
Lagrangian betweenness: detecting fluid transport bottlenecks in oceanic flows
Authors: Ser-Giacomi Enrico , Baudena Alberto , Rossi Vincent , Follows Mick , Vasile Ruggero , Lopez Cristobal , Hernandez-Garcia Emilio
Published: March 2021

 

The study of connectivity patterns in networks has brought novel insights across diverse fields ranging from neurosciences to epidemic spreading or climate. In this context, betweenness centrality has demonstrated to be a very effective measure to identify nodes that act as focus of congestion, or bottlenecks, in the network. However, there is not a way to define betweenness outside the network framework. Here we introduce the “Lagrangian betweenness”, an analogous quantity which relies only on the information provided by trajectories sampled across a generic dynamical system in the form of Finite Time Lyapunov Exponents, a widely used metric in Dynamical Systems Theory and Lagrangian oceanography. Our theoretical framework reveals a link between regions of high betweenness and the hyperbolic behavior of trajectories in the system. For example, it identifies bottlenecks in fluid flows where particles are first brought together and then widely dispersed. This has many potential applications including marine ecology and pollutant dispersal. We first test our definition of betweenness in an idealized double-gyre flow system. We then apply it in the characterization of transport by real geophysical flows in the semi-enclosed Adriatic Sea and the Kerguelen region of the highly turbulent Antarctic Circumpolar Current. In both cases, patterns of Lagrangian betweenness identify hidden bottlenecks of tracer transport that are surprisingly persistent across different spatio-temporal scales. In the marine context, high Lagrangian betweenness regions represent the optimal compromise between the heterogeneity of water origins and destinations, suggesting that they may be associated with relevant diversity reservoirs and hot-spots in marine ecosystems. Our new metric could also provide a novel approach useful for the management of environmental resources, informing strategies for marine spatial planning, and for designing observational networks to control pollutants or early-warning signals of climatic risks. 
Application of optical and radar data for lineaments mapping in Kerdous inlier of the Anti Atlas belt, Morocco
Authors: Jellouli Amine , El Harti Abderrazak , Adiri Zakaria , Chakouri Mohcine , El Hachimi Jaouad , Bachaoui El Mostafa
Published: March 2021

Lineament mapping is an important step for lithological and hydrothermal alterations mapping. It is considered as an efficient research task which can be a part of structural investigation and mineral ore deposits identification. The availability of optical as well as radar remote sensing data, such as Landsat 8 OLI, Terra ASTER and ALOS PALSAR data, allows lineaments mapping at regional and national scale. The accuracy of the obtained results depends strongly on the spatial and spectral resolution of the data. The aim of this study was to compare Landsat 8 OLI, Terra ASTER, and radar ALOS PALSAR satellite data for automatic and manual lineaments extraction. The module Line of PCI Geomatica software was applied on PC1 OLI, PC3 ASTER and HH and HV polarization images to automatically extract geological lineaments. However, the manual extraction was achieved using the RGB color composite of the directional filtered images N - S (0°), NE - SW (45°) and E - W (90°) of the OLI panchromatic band 8. The obtained lineaments from automatic and manual extraction were compared against the faults and photo-geological lineaments digitized from the existing geological map of the study area. The extracted lineaments from PC1 OLI and ALOS PALSAR polarizations images showed the best correlation with faults and photo-geological lineaments. The results indicate that the lineaments extracted from HH and HV polarizations of ALOS PALSAR radar data used in this study, with 1499 and 1507 extracted lineaments, were more efficient for structural lineament mapping, as well as the PC1 OLI image with 1057 lineaments.

Keywords Remote Sensing . OLI. ALOS PALSAR . ASTER . Kerdous Inlier . Anti Atlas
Epidemics and Human Mobility
Authors: Geisel Theo
Published: March 2021

The severity of infectious diseases and epidemics increases drastically, when pathogens start being transmitted between humans, as thereby they can dispose of human traffic networks for their spreading. This can transform an epidemic into a worldwide threatening pandemic, as the current COVID-19 crisis has shown. Traffic networks exist on multiple scales and the spreading of pathogens exhibits superdiffusive properties. This talk will emphasize and analyze the key role of human mobility for the modeling, forecast, and control of epidemic spreading. A major problem is posed by the limited availability of statistical data on human mobility. Various proxies are now utilized since we suggested dollar bills as proxies for human moblity.  Recent work on endemic diseases in populations open to migration will be discussed. 
Post-fire soil erosion risk map in Portugal: prediction and validation
Authors: Parente Joana , Lopes Ana , Girona-García Antonio , Basso Marta , Vieira Diana
Published: March 2021

Wildfires are a recurrent and increasing threat in Mainland Portugal, where over 4,500 thousand hectares of forests and shrublands have burned in the last 38 years. Landscapes affected by those wildfires have suffered an increase of soil erosion processes, which can negatively affect soil carbon storage, reduce fertility, forest productivity, and become a source of pollutants. Taking these in mind, the main objective of this study is to offer a ground base of post-fire soil erosion risk determination for Mainland Portugal, which will provide a set of tools to help forest managers in the post-fire decision-making, and therefore adequately implement mitigation measures to prevent such impacts.

Post-fire soil erosion was assessed by the applying the semi-empirical soil erosion model Revised Morgan–Morgan–Finney(Morgan, 2001), to the entire Portuguese forest and shrubland areas according to distinct scenarios (burn severity, climate). This study benefits from the use of several reliable official datasets of soil characteristics, as also from several model calibrations and validation with field data collected in the last 10 years for the 1st and 2nd post-fire years. The obtained soil erosion map identifies areas with higher post-fire erosion risk in the past and for future climate extremes. Findings of this study will be a valuable tool for forest managers to minimize the economic and environmental losses of vegetation fires in Portugal.

Acknowledgements

This work was supported and conducted in the framework of the FEMME project (PCIF/MPG/0019/2017) funded by FCT - Portuguese Foundation for Science and Technology. The study was also supported by: i) National Funds by FCT - Portuguese Foundation for Science and Technology, under the project UIDB/04033/2020; and, ii) National Funds by FCT - Portuguese Foundation for Science and Technology, under the project UID/AMB/50017/2019. Data were provided by the European Forest Fire Information System – EFFIS (http://effis.jrc.ec.europa.eu) of the European Commission Joint Research Centre.
The Western Eurasian Basin Halocline in 2017: Insights From Autonomous NO Measurements and the Mercator Physical System 
Authors: Bertosio Cécilia , Provost Christine , Sennéchael Nathalie , Artana Camila , Athanase Marylou , Boles Elisabeth , Lellouche Jean-Michel , Garric Gilles
Published: March 2021

We present the first sensor‐based profiles of the quasi‐conservative NO parameter obtained with an autonomous ice‐tethered buoy in the Arctic Ocean. Data documented the halocline in the Transpolar Drift and Nansen Basin in 2017. A NO minimum was found in the Nansen Basin on a σ‐horizon of 27.8 kg·m−3 corresponding to the lower halocline, while a lower NO minimum of 380 μM straddled the 27.4 σ‐horizon and marked the cold halocline in the Transpolar Drift. Back trajectories of water parcels encountered along the buoy drift were computed using the Mercator physical system. They suggested that waters within the NO minimum at 27.4 kg·m−3 could be traced back to the East Siberian Sea continental. These trajectories conformed with the prevailing positive phase of the Arctic Oscillation. The base of the lower halocline, at the 27.85 σ‐horizon, corresponded to the density attained in the deepest winter mixed layer north of Svalbard and cyclonically slowly advected from the slope into the central Nansen Basin. The 27.85 σ‐horizon is associated with an absolute salinity of 34.9 g·kg−1, a significantly more saline level than the 34.3 psu isohaline commonly used to identify the base of the lower halocline. This denser and more saline level is in accordance with the deeper winter mixed layers observed on the slopes of Nansen Basin in the last 10 years. A combination of simulations and NO parameter estimates provided valuable insights into the structure, source, and strength of the Arctic halocline.
Interpolating data on the Cubed Sphere with Spherical Harmonics
Authors: Croisille Jean-Pierre , Bellet Jean-Baptiste , Brachet Matthieu
Published: March 2021

The Cubed Sphere is a grid commonly used in numerical simulation in climatology. In this talk we present recent progress
on the algebraic and geometrical properties of this highly symmetrical grid.
First, an analysis of the symmetry group of the Cubed Sphere will be presented: this group 
is identified as the group of the Cube, [1]. Furthermore, we show how to construct a discrete Spherical Harmonics (SH) basis associated to 
the Cubed Sphere. This basis displays a truncation scheme relating the zonal and longitudinal 
mode numbers reminiscent of the rhomboidal truncation on the Lon-Lat grid.
The new analysis allows to derive new quadrature rules of  interest for applications in any kind of spherical modelling. In addition,
we will comment on applications in mathematical climatology and meteorology, [2].

[1] J.-B. Bellet, Symmetry group of the equiangular Cubed Sphere, preprint, IECL, Univ. Lorraine, 2020, submitted

[2] J.-B. Bellet, M. Brachet and J.-P. Croisille, Spherical Harmonics on The Cubed Sphere, IECL, Univ. Lorraine, 2021, Preprint.
Water, heat and salt budgets over South East Asia seas : a high resolution modeling approach
Authors: Herrmann Marine , Trinh Bich Ngoc , Ulses Caroline , Marsaleix Patrick , Duhaut Thomas , To Duy Thai , Ouillon Sylvain
Published: March 2021

South East Asia seas, that include the South China Sea and the Indonesian Seas, transfer the warm and light waters of the surface branch of the global thermohaline circulation between the Pacific and Indian Oceans. To better understand the key contribution of South East Asia seas in the regional and global climate and ocean circulation, it is therefore essential to improve our knowledge of the functioning and variability at different scales of water, heat and salt budgets over this region. The complex topography of this region makes it difficult to study those budgets based on in-situ measurements only. Numerical studies are necessary and relevant to complement and interpret those measurements, however until now, most of numerical studies were performed at low resolution and/or on short periods.

 

To better quantify and understand the contributions of ocean, rivers and atmosphere to the variability at different scales of the water, heat and salt budgets over South East Asia seas, high resolution configurations (< 5 km) of the SYMPHONIE ocean model are developed over the area. State of the art datasets available from COPERNICUS and ECMWF are used to prescribe boundary conditions. Each term of the budgets is computed online in order to obtain rigorously closed budgets.

 

This methodology applied on the 2009-2018 period, that includes strong El Niño and La Niña years as well as neutral years, allows us to better characterize the seasonal to interannual variability of water, salt and heat budgets over the South East Asia seas, by quantifying and explaining the contribution of each factor (lateral fluxes, surface fluxes, rivers, internal variations, ENSO). We examine in particular the surface salinification of the South China Sea that was observed by previous authors between 2012 and 2016 (Zeng et al. 2018, doi:10.1002/2017GL076574) : our simulations suggest that it is mostly related to an increase of net lateral water influx at Luzon strait, itself induced by a deficit of precipitation over the region, rather than to an increase of the salinity of the inflowing water. We finally also explore the role of tides and mesoscale processes. This methodology, our key results and the future steps of this work, that include the on-going development of an ocean-atmosphere regional coupled model, will be synthetically summarized.
The long-term evolution of the Earth mantle with a basal magma ocean
Authors: Labrosse Stephane , Morison Adrien , Bolrão Daniela , Rozel Antoine , Ballmer Maxim , Deguen Renaud , Alboussière Thierry , Tackley Paul
Published: March 2021

The early evolution of the Earth was likely affected by a large scale magma ocean, in particular in the aftermath of the giant impact that formed the Moon. The exact structure and dynamics of the Earth following that event is unknown but several possible scenarios feature the existence of a basal magma ocean (BMO), whose last remaining drops may explain the current seismically detected ultra low velocity zones. The presence of a BMO covering the core carries many implications for the dynamics and evolution of the overlying solid mantle. The phase equilibrium between the magma and the solid mantle allows matter to flow through the boundary by melting and freezing. In practice, convective stresses in the solid create a topography of the interface which displaces the equilibrium. Heat and solute transfer in the liquid acts to erase this topography and, if this process is faster than that the producing topography, the boundary appears effectively permeable to flow. This leads to convective motions much faster than in usual mantle convection. We developed a mantle convection model coupled to a model for the thermal and compositional evolution of the BMO and the core that takes into account the phase equilibrium at the bottom of the solid mantle. It also includes the fractional crystallisation at the interface and net freezing of the magma ocean. Early in the history, convection in the mantle is very fast and dominated by down-welling currents. As fractional crystallisation proceeds, the magma ocean gets enriched in FeO which makes the cumulate to also get richer. Eventually, it becomes too dense to get entrained by mantle convection and starts to pile up at the bottom of the mantle, which inhibits direct mass flow through the phase change boundary. This allows a thermal boundary layer and hot plumes to develop.

This model therefore allows to explain the present existence of both residual partial melt and large scale compositional variations in the lower mantle, as evidenced by seismic velocity anomalies. It also predicts a regime change between early mantle convection dominated by down-welling flow to the onset of hot plumes in the more recent past.
The influence of lithospheric rheology on escarpment evolution at divergent margins: a numerical approach
Authors: Macedo Silva João Pedro , Sacek Victor , Monteiro da Silva Rafael
Published: March 2021

The evolution of escarpments bordering the coast during the post-rift phase is numerically simulated mostly by landscape surface processes models. However, there are few thermomechanical models that were applied to study the post-rift evolution of these escarpments. In the present work, we used a finite element thermomechanical model to simulate lithospheric extension and evaluate the sensitivity of escarpment amplitude over time under different geological and rheological conditions from the onset of lithospheric extension to the post-rift phase. The results showed that the evolution of escarpment amplitude and its preservation for tens of millions of years are sensitive to crustal and lithospheric thicknesses. We observed that escarpment preservation is higher for scenarios with a thinner crust with a strong lower crust and a thicker lithospheric mantle. This behavior is related to the degree of coupling between the crust and lithospheric mantle that affect the vertical displacement of the lithosphere due to flexural and isostatic response. Additionally, even without surface processes of erosion and sedimentation, the amplitude of the escarpment can monotonically decrease with time due to the lateral flow of the lower crust. This effect is expressive in the scenarios where the effective viscosity of the lower crust is relatively low and the upper crust is rheologically decoupled from the lithospheric mantle. In these cases, the amplitude of the escarpment can decrease from 2-3 km during the rifting phase to less 1 km after 40 Myr after the onset of lithospheric extension. On the other hand, in scenarios where the crust is rheologically coupled, the amplitude of the escarpment after 100 Myr since the lithospheric stretching is only ~25% smaller than maximum amplitude observed during the rifting phase. We conclude that the rheological structure of the lithosphere can play an important role in the formation and preservation of escarpments at divergent margins simultaneously with surface process.
Anti-oxidative response of Cistus salviifolius L. grown in gossan mine wastes amended with ash and organic residues
Authors: Carvalho Luísa C. , Santos Erika , Saraiva Jorge A. , Abreu Maria Manuela
Published: March 2021

Mine waste heaps can be considered extreme environments, due to their high concentrations of potentially hazardous elements (PHE). When PHE are combined with adverse physical characteristics and low contents of organic matter and nutrients, the development of the majority of plant species is impaired and the biodiversity of the area is severely reduced. The abandoned São Domingos mining area represents such an environment. It is located in the Iberian Pyrite Belt (South of the Iberian Peninsula) and has one of the largest concentrations of polymetallic massive sulfide deposits in Europe.

Some autochthonous plant species are well adapted to extreme environments and are able to grow naturally in degraded areas, contributing to minimize the negative chemical impacts and improve the landscape quality. However, the environmental rehabilitation processes associated to the development of these plants (phytostabilization) are very slow and the combined use of materials/wastes that improve some physico-chemical characteristics of the matrix is necessary. This work studied the physiological response of C. salvifoliius, an autochthonous species, tolerant to growth in harsh environments, when grown in gossan mine wastes from the mine of São Domingos amended with organic/inorganic wastes. The amendments used were (g/kg of gossan): biomass ash (BA, 2.5), a mixture of organic residues (OR, 120) and a mixture of both (BA+OR).

The amendments that comprised organic wastes (OR and BA+OR) gave rise to the best vegetative development, without visible signs of toxicity and with the lowest concentrations of hydrogen peroxide (H2O2). Plants grown in the presence of organic wastes also had better levels of cell redox status and a large pool of antioxidants. Although both roots and shoots of these plants had low levels of H2O2, in roots, both glutathione and ascorbate had high levels of oxidation.

A successful environmental rehabilitation has to take into account both the amendments applied and also the growth and the ability of the plant cover to adapt to the adverse environmental conditions imposed upon it. Cistus salvifoliius was able to grow better and withstand the high PHE levels of the gossan material when organic matter was used as amendment. In those conditions, the plants had a more functional anti-oxidative system that enabled them to cope with oxidative stress. A better plant cover was achieved and chemical properties of the mine wastes were improved, such as lower concentrations of PHE in the available fraction, higher fertility and water-holding capacity.
Dynamical Landscape and Multistability of a Climate Model
Authors: Margazoglou Georgios , Lucarini Valerio , Grafke Tobias , Laio Alessandro
Published: March 2021

We apply two independent data analysis methodologies to locate stable climate states in an intermediate complexity climate model and analyze their interplay. First, drawing from the theory of quasipotentials, and viewing the state space as an energy landscape with valleys and mountain ridges, we infer the relative likelihood of the identified multistable climate states, and investigate the most likely transition trajectories as well as the expected transition times between them. Second, harnessing techniques from data science, specifically manifold learning, we characterize  the data landscape of the simulation output to find climate states and basin boundaries within a fully agnostic and unsupervised framework. Both approaches show remarkable agreement, and reveal, apart from the well known warm and snowball earth states, a third intermediate stable state in one of the two climate models we consider. The combination of our approaches allows to identify how the negative feedback of ocean heat transport and entropy production via the hydrological cycle drastically change the topography of the dynamical landscape of Earth's climate.
Reconstructing daily cycles of canopy water for the validation of (subdaily) microwave estimates
Authors: Vermunt Paul , Steele-Dunne Susan , Khabbazan Saeed , van de Giesen Nick , Judge Jasmeet
Published: March 2021

Monitoring rapid, subdaily vegetation water dynamics is key to address fundamental questions surrounding the role of vegetation in the water, carbon and energy cycles, and to provide essential information for detecting and monitoring droughts on local to global scales. Active and passive microwave remote sensing has been used to estimate vegetation water content (VWC), e.g. using vegetation optical depth (VOD), because of the sensitivity of microwave observables to plant dielectric properties. These estimates were used for applications such as fuel load estimation, soil moisture retrieval, crop monitoring and studies on drought propagation. The expected availability of subdaily observations from the next generation of satellites opens the opportunity to also monitor rapid vegetation water dynamics. However, one of the main challenges is the validation of subdaily microwave products.

VWC is commonly measured through destructive sampling, which is labor- and time-intensive, in particular when this has to be done multiple times per day. Here, we present a proof of concept for a more efficient validation method, using continuously measuring sensors. First, we present our latest study on reconstructing continuous records of VWC in corn, using hydrometeorological data and sparse destructive sampling [Vermunt et al., in prep.]. Second, we present the estimation of surface canopy water (dew, rainfall interception), and illustrate the value of both data sets by using them to analyse our tower-based observations of subdaily fully polarimetric L-band backscatter [1]. The results demonstrate the potential for radar to monitor rapid vegetation water dynamics.

[1] Vermunt, P. C., Khabbazan, S., Steele-Dunne, S. C., Judge, J., Monsivais-Huertero, A., Guerriero, L., & Liu, P. W. (2020). Response of Subdaily L-Band Backscatter to Internal and Surface Canopy Water Dynamics. IEEE Transactions on Geoscience and Remote Sensing.