bluuebunny/crossref_metadata_2025 huggingface dataset:
Atlantic multi-centennial variability in IPSL-CM6A-LR climate model
Authors: Jiang Weimin , Gastineau Guillaume , Codron Francis
Published: March 2021

A pronounced multi-centennial variability of the Atlantic meridional overturning circulation (AMOC) is found to be regulated by the salinity exchanges between the Atlantic and Arctic ocean in the IPSL-CM6A-LR atmosphere-ocean coupled model. The AMOC variations are preceded by salinity-driven density anomalies in the main deep convection sites in the Labrador and Greenland seas. Associated with a strong AMOC, the Arctic sea ice export through the Fram Strait reduces due to the decreased sea ice volume and anomalous northward currents. Anomalous freshwater hence accumulates at the surface in the Central Arctic. Meanwhile, the enhanced Atlantic inflow enters the Arctic through the Barents Sea and leads to a positive salinity in the Eastern Arctic subsurface. The surface freshwater anomalies last for 4 to 5 decades before they eventually reach the Lincoln Sea north of Greenland. The associated oceanic currents around Greenland reorganize, favoring the anomalous Arctic freshwater export to the North Atlantic and intensifying the stratification in deep convection sites. The AMOC then weakens, and the Central Arctic presents a positive surface salinity anomaly in turn. The oscillation switches to the opposite phase. These AMOC and sea ice fluctuations modulate climate worldwide, with a strong AMOC leading to a warming of 0.4°C in the northern extratropics, reaching up to 1°C in the Arctic lower troposphere during winter. In all seasons, a northward displacement of the intertropical convergence zone is also simulated.
Mapping the Geogenic Radon Hazard Index of Italy
Authors: Giustini Francesca , Procesi Monia , Finoia MariaGrazia , Sassi Raffaele , Mazzoli Claudio , Ciotoli Giancarlo
Published: March 2021

Radon generation and migration from the soil toward the surface are natural processes that can lead to radon entry in buildings, thus constituting a health risk. The analysis and the modelling of these processes can be thought of as the contribution of different proxies representing the geological radon source (GRS) (e.g., geology, soil properties, radionuclide content), and the pathways (e.g., faults, karst) that favour the geological radon migration (GRM) in the subsoil. The aggregation of these quantities can be used to construct a geogenic radon hazard index (GRHI) map that can be understood as a measure of the susceptibility of an area to increased indoor radon concentration for geogenic reasons (Radon Priority Areas, RPA).

A number of direct and indirect models have been developed in order to create GRHI maps of a certain region by using both deterministic and probabilistic models. Here, we propose a bottom-up procedure through the integration of different factors (predictors and/or proxies) and by weighs their importance. In particular, we first propose to construct a GRHI map of the whole Italian territory using a GIS-based (spatial) multicriteria decision analysis (SMCDA). SMCDA uses the Analytical HierarchyProcess (AHP) to assess the importance of the factors and to derive their relative weights and, consequently, it determines the overall ﬁnal scores.

Lithologies of the National Geological Map of Italy (1:1000000) were reclassified in few homogeneous classes and ranked according to the associated mean content of uranium, thorium and potassium available from GEMAS (http://gemas.geolba.ac.at/) and FOREGS (http://weppi.gtk.fi/publ/foregsatlas/index.php) database by using a multivariate statistical approach. In this way the intermediate map of the GRS was obtained. SMCDA was then applied by using the GRS map and the maps of other factors, such as the fine fraction of the soil (LUCAS top-soil database, https://esdac.jrc.ec.europa.eu/projects/lucas), the fault density map (Italian national/regional datasets), the map of the karst areas (https://www.whymap.org/whymap/EN/Maps_Data/Wokam/wokam_node_en.html) and the map of the heat flow of Italy. All these factors were standardised by using fuzzy classification to transform input data to a 0/1 scale. The standardised factors are weighted by using AHP and then summed to obtain the final GRHI map. All maps are constructed at the same grid resolution of the European Atlas of Natural Radiation (10x10km) (https://remon.jrc.ec.europa.eu/About/Atlas-of-Natural-Radiation) published by the Joint Research Centre (JRC) of the European Commission.
Dynamics of a Diabatic Layer in the quasi-geostrophic framework
Authors: Klein Rupert , Schielicke Lisa , Pfahl Stephan , Khouider Boualem
Published: March 2021

Quasi-geostrophic (QG) theory describes the dynamics of synoptic scale flows in the trophosphere that are balanced with respect to both acoustic and internal gravity waves. Within this framework, effects of (turbulent) friction near the ground are usually represented by invoking Ekman Layer theory. The troposphere covers roughly the lowest ten kilometers of the atmosphere while Ekman layer heights are typically just a few hundred meters. However, this two-layer asymptotic theory does not explicitly account for substantial changes of the potential temperature stratification due to diabatic heating associated with cloud formation or with radiative or turbulent heat fluxes, which, in the middle latitudes, can be particularly important in roughly the lowest three kilometers. To alleviate this constraint, this work extends the classical QG plus Ekman layer model by introducing an intermediate, dynamically and thermodynamically active layer, called the "Diabatic Layer" here. The flow in this layer is also in acoustic, hydrostatic, and geostrophic balance but, in contrast to QG flow, variations of potential temperature are not restricted to small deviations from a stable and time independent background stratification. Instead, within this layer, diabatic processes are allowed to affect the leading-order stratification. As a consequence, the Diabatic Layer modifies the pressure field at the top of the Ekman layer, and with it the intensity of Ekman pumping seen by the quasi-geostrophic bulk flow. This leads to a new model for the coupled dynamics of the bulk troposphere, the diabatic layer, and the Ekman layer when strong diabatic processes substantially change the stratification in the lower part of the atmosphere. 
Radiative forcing over the Arctic of aerosols from the August 2017 Canadian and Greenlandic wildfires
Authors: Calì Quaglia Filippo , Meloni Daniela , di Sarra Alcide Giorgio , Di Iorio Tatiana , Ciardini Virginia , Pace Domenico , Muscari Giovanni , Becagli Silvia , Cacciani Marco , Ortega Ivan , Hannigan James W. , Holben Brent N.
Published: March 2021

Extended and intense wildfires occurred in Northern Canada and, unexpectedly, on the Greenlandic West coast during summer 2017. The thick smoke plume emitted into the atmosphere was transported to the high Arctic, producing one of the largest impacts ever observed in the region. Evidence of Canadian and Greenlandic wildfires was recorded at the Thule High Arctic Atmospheric Observatory (THAAO, 76.5°N, 68.8°W, www.thuleatmos-it.it) by a suite of instruments managed by ENEA, INGV, Univ. of Florence, and NCAR. Ground-based observations of the radiation budget have allowed quantification of the surface radiative forcing at THAAO. 

Excess biomass burning chemical tracers such as CO, HCN, H2CO, C2H6, and NH3 were  measured in the air column above Thule starting from August 19 until August 23. The aerosol optical depth (AOD) reached a peak value of about 0.9 on August 21, while an enhancement of wildfire compounds was  detected in PM10. The measured shortwave radiative forcing was -36.7 W/m2 at 78° solar zenith angle (SZA) for AOD=0.626.

MODTRAN6.0 radiative transfer model (Berk et al., 2014) was used to estimate the aerosol radiative effect and the heating rate profiles at 78° SZA. Measured temperature profiles, integrated water vapour, surface albedo, spectral AOD and aerosol extinction profiles from CALIOP onboard CALIPSO were used as model input. The peak  aerosol heating rate (+0.5 K/day) was  reached within the aerosol layer between 8 and 12 km, while the maximum radiative effect (-45.4 W/m2) is found at 3 km, below the largest aerosol layer.

The regional impact of the event that occurred on August 21 was investigated using a combination of atmospheric radiative transfer modelling with measurements of AOD and ground surface albedo from MODIS. The aerosol properties used in the radiative transfer model were constrained by in situ measurements from THAAO. Albedo data over the ocean have been obtained from Jin et al. (2004). Backward trajectories produced through HYSPLIT simulations (Stein et al., 2015) were also employed to trace biomass burning plumes.

The radiative forcing efficiency (RFE) over land and ocean was derived, finding values spanning from -3 W/m2 to -132 W/m2, depending on surface albedo and solar zenith angle. The fire plume covered a vast portion of the Arctic, with large values of the daily shortwave RF (< -50 W/m2) lasting for a few days. This large amount of aerosol is expected to influence cloud properties in the Arctic, producing significant indirect radiative effects.
Towards AI in Array Databases
Authors: Campos Escobar Otoniel José , Baumann Peter
Published: March 2021

Multi-dimensional arrays (also known as raster data, gridded data, or datacubes) are key, if not essential, in many science and engineering domains. In the case of Earth sciences, a significant amount of the data that is produced falls into the category of array data. That being said, the amount of data that is produced daily from this field is huge. This makes it hard for researchers to analyze and retrieve any valuable insight from it. 1-D sensor data, 2-D satellite imagery, 3-D x/y/t image time series and x/y/z subsurface voxel data, 4-D x/y/z/t atmospheric and ocean data often produce dozens of Terabytes of data every day, and the rate is only expected to increase in the future. In response, Array Databases systems were specifically designed and constructed to provide modeling, storage, and processing support for multi-dimensional arrays. They offer a declarative query language for flexible data retrieval and some, e.g., rasdaman, provide federation processing and standard-based query capabilities compliant with OGC standards such as WCS, WCPS, and WMS. However, despite these advances, the gap between efficient information retrieval and the actual application of this data remains very broad, especially in the domain of artificial intelligence AI and machine learning ML.

In this contribution, we present the state-of-art in performing ML through Array Databases. First, a motivating example is introduced from the Deep Rain Project which aims at enhancing rainfall prediction accuracy in mountainous areas by implementing ML code on top of an Array Database. Deep Rain also explores novel methods for training prediction models by implementing server-side ML processing inside the database. A brief introduction of the Array Database rasdaman that is used in this project is also provided featuring its standard-based query capabilities and scalable federation processing features that are required for rainfall data processing. Next, the workflow approach for ML and Array Databases that is employed in the Deep Rain project is described in detail listing the benefits of using an Array Database with declarative query language capabilities in the machine learning pipeline. A concrete use case will be used to illustrate step by step how these tools integrate. Next, an alternative approach will be presented where ML is done inside the Array Database using user-defined functions UDFs. Finally,  a detailed comparison between the UDF and workflow approach is presented explaining their challenges and benefits.
Combining statistical learning and geostatistical approaches in a spatiotemporal framework for low flow estimation
Authors: Laimighofer Johannes , Melcher Michael , Parajka Juraj , Laaha Gregor
Published: March 2021

This paper aims to develop a spatiotemporal model to estimate monthly low flow quantiles Q95 [P(Q<Q95=0.05)] standardized by catchment area in Austria. Our dataset consists of 325 gauging stations that where consistently monitored between 1976 to 2015, and it covers about 60% of the national territory of Austria.

In a first step we are adapting a spatiotemporal model initially designed for modeling air pollution data. This approach is based on empirical orthogonal functions (EOF), that should capture the temporal structure of the spatiotemporal model. The EOFs are weighted by regression coefficients estimated by universal kriging. We extend the model by using GLM-boosting, LASSO, Principal Component Regression (PCR) and Random Forest (RF) for selecting the regression coefficients of the EOFs. Furthermore, we do not limit the kriging structure of the residual field to geographical coordinates but use a broader approach of physiographic kriging. In a second step we implement separate models for the mean parts of the model and the residual parts of the model. The mean field is defined by statistical learning methods as RF, GAM-boosting, LASSO and Support Vector Machines (SVM). For the residual field we define two different approaches, either the method developed in the first step or spatiotemporal kriging.

Model performance is evaluated by cross validation and the best model is selected by the mean squared error (MSE).

 
Monitoring Leaky Barriers for Natural Flood Management (NFM) within a community-led project
Authors: Powell Gabrielle , Clark Joanna , Nisbet Tom
Published: March 2021

Natural Flood management (NFM) is a nature-based solution and catchment-based approach to flood mitigation.  Leaky barriers are a form of NFM and are popular amongst community groups working with natural processes as an affordable and sustainable action that they themselves can implement without investment in large infrastructure. At our research site, over 30 Leaky barriers have been implemented along a mile-long stretch of flashy river by a local community flood group and landowner in an attempt to decrease flood risk downstream in partnership with the Environment Agency. The effectiveness of these leaky barriers is being monitored in a number of ways, including: river flow, river level, geomorphic surveys and time-lapse footage. We describe the project dynamics and operational context that shaped the adopted control-intervention monitoring design. Based on previous studies, we hypothesize that leaky barriers will be most effective at mitigating smaller, rather than large flood events, such as in 2007. This is tested by examining the data collected over 2019-20, which includes storm Dennis (13th-19th February 2020) that caused widespread flooding across England and Wales. The results will contribute to a wider evidence base being collected by the Environment Agency, exploring the context in which community projects and monitoring take place against the changing expectations of funders and the evaluation of data produced.
Nonequilibrium scaling vs. the temporal evolution of turbulence
Authors: Waclawczyk Marta , Wójtowicz Jan , Malinowski Szymon
Published: March 2021

Despite many airborne measurements and research campaigns our
understanding of turbulence in free atmosphere is still far from
sufficient. Part of the problem is the limited amount of measurement
data, another part is measurement errors and last, but not least
element is inadequate or not satisfactory data analysis. This
presentation addresses some aspects of this last issue.
The simplest way to characterize turbulence is to define/measure
characteristic velocity U and length L (or time T) scales of
turbulent  eddies. Two quantities necessary to estimate them are the
turbulence kinetic energy K and the turbulence kinetic energy
dissipation rate.
A universal scaling relation between dissipation rate, turbulence
kinetic energy and the turbulence length scale follows from the
classical picture of the equilibrium Richardson-Kolmogorov cascade.
There, the energy is transported between scales in a downward cascade
until it is dissipated into heat by the smallest eddies. This
universal scaling is a basis of many turbulence models, also in the
context of atmospheric applications. However, a number of recent
papers suggest that a universal, although different from the
classical, scaling could also be observed in unsteady turbulent flows,
which ate typical in the free atmosphere.
In this study we investigate the nonequilibrium scaling relation
between the integral length scale of turbulence and dissipation rate
using velocity signals from various airborne measurements of
atmospheric cloud turbulence, including that in and around convective
clouds. A research aircraft measures 1D intersection of turbulent
velocity field as a time series collected along the flight tajectory.
Hence,  information on  temporal behavior (decay or development) of
turbulence is not directly available. In this study we show how this
important information can be recovered based on the observed scaling
relations.
Spatiotemporal variations of isotopes in snow and snowmelt in the subarctic setting at Pallas catchment, Finland
Authors: Noor Kashif , Ala-Aho Pertti , Marttila Hannu , Kløve Bjørn
Published: March 2021

Due to the rise in global temperature, changes in precipitation patterns are predicted particularly in Arctic regions. Such changes in patterns and modifications in typical snow to precipitation ratios will affect the snowpack thickness and the timing of snow accumulation and snow melting. Stable water isotopes (δ2H, δ18O)  are one of the latest tools in exploring and tracing such changes, however, snow isotope and particularly snowmelt isotope datasets are rarely available which hamper the high-resolution isotope based hydrological investigations in Arctic regions. In this study, we perform an investigation for evaluating spatiotemporal variations in stable isotopes of snow and snowmelt water. Our Pallas research catchment is located in a subarctic setting in northern Finland. The measurements were made at 11 locations along a 2 km snow survey, which is established on the transect of the catchment, comprising of different landscape features (i) forested hillslope, (ii) mixed forest and (iii) open mires. We sampled depth-integrated bulk snowpack and fixed 5 cm incremental snow stratigraphy profile in snowpits. For snowmelt sampling, we used a system of snowmelt lysimeter, deployed at 11 locations. The bulk snowpack samples were collected biweekly, fixed 5 cm incremental stratigraphic snowpit samples during the period of maximum snowcover thickness and during the start of peak melting, during the peak melting and after the peak melting. Snowmelt samples were collected daily during the spring season until the complete disappearance of snow with complementary measurements of snowmelt flux, snow density and snow water equivalent. Our results indicate the higher mean values of snowmelt isotopes relative to the bulk snowpack and surface snow isotopes. The snow isotope profiles in snowpack reveal that the isotopes at the snow-air and snow-ground interfaces are enriched in heavier isotopes as compared to the middle of the snowpack. The snowmelt isotopes show that the isotopes are initially depleted in heavier isotopes but with the progress of melting, they start to become enriched. A well defined depleted to enriched pattern is observed at different locations in the forested hillslope area, while a relatively dispersed depleted to enriched pattern is observed at different locations in the mixed forested area. Our unique high-resolution dataset of snow and snowmelt isotopes will be useful in many applications; such as for evaluating post-depositional isotope modification in the seasonal snowpack, developing tracer-aided mass and energy based snow models. The establishment of snowmelt isotope dataset, showing spatiotemporal variability of snowmelt isotopes, is an important step forward in isotope based plant-water uptake studies and hydrological analyses in snow-influenced catchments.
Assessing potential impacts on the air traffic routes due to an ash-producing eruption on Jan Mayen Island (Norway)
Authors: Titos Manuel , Martínez Beatriz , Barsotti Sara , Sandri Laura , Folch Arnau , Mingari Leonardo , Costa Antonio , Macedonio Giovanni
Published: March 2021

Jan Mayen Island (Norway), located in the North Atlantic, is considered the world’s northernmost active subaerial volcano, with at least five eruptive periods recorded during the last 200 years. Explosive activity of the volcano may seriously affects the nearby important air traffic routes. However, no quantitative studies on the possible impact of a new explosive volcanic eruption on the air traffic have been conducted.  In this work, we statistically characterise the spatial and temporal distribution of airborne volcanic ash cloud and its persistence at different flight levels. Since current operational forecast products do not always meet the requirements of the aviation sector and related stakeholders (using coarse time and space scales, with outputs on a 40 km horizontal resolution grid and 6 hour time averages), and they neglect epistemic/aleatory uncertainties in quantitative forecasts on real time, we propose hourly high resolution hazard maps over a 3D-grid covering a 2 km-resolution spatial domain 2000 km x 2000 km wide. We present the use of high-performance computing (HPC) to overcome the computational limitations associated with unbiased long-term probabilistic volcanic hazard assessment (PVHA) .Considering a continuum of possible combinations of Eruptive Source Parameters (ESP) to assess and quantify the uncertainty, and the natural variability associated with wind fields over 20 years of data, from 1999 to 2019, we run thousands of analytical solutions (numerical simulations) using the most recent version of the FALL3D model. As a result, the first comprehensive long-term PVHA for Jan Mayen volcanic island is presented.
Land subsidence and sea-level rise for six coastal zones of the Mediterranean region: implications for flooding scenarios for 2100 from the SAVEMEDCOASTS-2 project
Authors: Crosetto Michele , Anzidei Marco , Forlenza Giovanna , Navarro José , Patias Petros , Georgiadis Charalampos , Doumaz Fawzi , Trivigno Maria Lucia , Falciano Antonio , Greco Michele , Serpelloni Enrico , Vecchio Antonio , Gao Qi , Barra Anna
Published: March 2021

Here we show and discuss the first results arising from the SAVEMEDCOASTS-2 Project (Sea Level Rise Scenarios along the Mediterranean Coasts - 2, funded by the European Commission ECHO), which aims to respond to the need for people and assets prevention from natural disasters in the Mediterranean coastal zones placed at less than 1 m above sea level, which are vulnerable to the combined effect of sea-level rise and land subsidence.

We use geodetic data from global navigation satellite system (GNSS), synthetic aperture radar interferometric measurements (InSAR), Lidar and tide gauge data, and the latest IPCC - SROCC projections of sea-level rise released by the Intergovernmental Panel on Climate Change, to estimate the Relative Sea Level Rise to realize marine flooding scenarios expected for 2100 AD in six targeted areas of the Mediterranean region.

We focus on the Ebro (Spain), Rhone (France), and Nile (Egypt) river deltas; the reclamation area of Basento (Italy), the coastal plain of Thessaloniki (Greece), and the Venice lagoon (Italy). Results, from Copernicus Sentinel-1A (S1A) and Sentinel-1B (S1B) sensors, highlighted the variable spatial rates of land subsidence up to some cm/yr in most of the investigated areas representing a relevant driver of local SLR. All the investigated zones show valuable coastal infrastructures and natural reserves where SLR and land subsidence are exacerbating coastal retreat, land flooding, and storm surges.

The hazard implications for the population living along the shore should push land planners and decision-makers to take into account scenarios similar to that reported in this study for cognizant coastal management.
Optic-fiber gravity frequency transfer network
Authors: Hoang Anh The , Shen WenBin
Published: March 2021

According to Einstein’s general relativity theory (GRT), a clock at a position with higher potential runs faster than a clock at a position with lower potential. Hence, inversely, one can determine the gravity potential (geopotential) and orthometric height based on precise clocks. If a clock with an accuracy of 10-18 is used, the geopotential difference between two points can be determined with an accuracy of centimeters level. With the rapid development of science and technology, optical clocks achieve 10-18 stability, which opens up opportunity for scientists to practically determine geopotential as well as orthometric height using optical clocks. One of the challenges of classical geodesic in the long time has been the unification of local hight systems. To complete this task is very difficult because each country has a regional high system. This problem can be solved if using a clock network, which overcomes the weaknesses of the spirit leveling method. Here we provide a formulation to establish a model of a network using optical clocks linked together by optical fibers for the purpose of determining the geopotential and establishing a unified world hight system at centimeter accuracy level. This study is supported by National Natural Science Foundation of China (NSFC) (grant Nos. 41721003, 42030105, 41631072, 41874023, 41804012), and Space Station Project (2020)228.

Key words: GRT, optical clocks network, frequency transfer, geopotential, orthometric height
Observed and simulated zonally asymmetric zonal wind patterns under NAO conditions
Authors: İlhan Aslı , Demirhan Deniz , Ünal Yurdanur
Published: March 2021

The North Atlantic Oscillation (NAO), coexistent meridional oscillation of subpolar Icelandic low and the subtropical Azores high dominates the Northern Hemispheric winter climate. Variability in the circulation of NAO may activate the extreme weather events, such as the enhanced zonal winds, in northeast America, Atlantic and Eurasia. On the other hand variability in the zonal wind patterns effects the position of the NAO events. It is more relevant to investigate the interaction between NAO and the weather patterns during the winter time since NAO is powerful during winter. Hence the wintertime weather systems are highly altered by such an impact. Analysis indicate that negative and positive phases of NAO mainly modulate the local cyclonic and anticyclonic wave characteristics and hence the zonally asymmetric circulation of the middle atmosphere. Zonal asymmetries in the weather patterns originate from ocean-continent temperature gradients and topographical contrasts after all solar incident radiation is almost uniform over the longitudes. Thus zonally asymmetric patterns for certain variables such as zonal winds show strong seasonal dependence and highly correlate with the climatological position of the NAO mainly in the winter hemisphere. In this study longitudinal differences in the zonal wind is analyzed in order to observe its strong influence on the evolution of NAO. Zonal asymmetries of zonal wind is examined by evaluating the deviation from zonal mean of the long term annual average of both winter and spring months from December to April. Zonal winds up to 100km for winter and spring is examined between 2006-2100 using CMIP5 MPI-ESM-MR RCP4.5 scenario for the extratropical and the polar latitudes. Additionally ERA5 reanalysis data is used to identify the ability of CMIP5 Reference Period (RP) data to capture the observed patterns for the years from 1979 to 2005.

Acknowledgements: This study is supported by TUBİTAK (The Scientific and Technology Research Council of Turkey), The Scientific and Technological Research Projects Funding Program, 1001. The projects number is 117Y327.
Development of a Seabed Geomorphology classification approach; aspiring towards a robust tool to support comprehensive and consistent seabed mapping 
Authors: Dove Dayton , Nanson Rachel , Bjarnadóttir Lilja , Guinan Janine , Gafeira Joana , Post Alix , Dolan Margaret F.J. , Stewart Heather , Arosio Riccardo
Published: March 2021

In 2016, through a collaboration between marine mapping programmes in Norway, Ireland, and the UK, we published a new classification scheme to aid the characterisation of seabed geomorphology (Dove et al., 2016). The classification scheme was developed to address shared objectives and challenges in seabed mapping, particularly to enable more consistent classification where required. The novel aspect of this framework was the effort to independently describe seabed features according to their observed physical 1-Morphology, and the more subjective interpretation of their origin and evolution (2-Geomorphology). Initial application of the approach within our own groups and externally proved promising, and through the welcome involvement of colleagues from Geoscience Australia, we continued to progress and improve the approach.

We are now within the second phase of the project, which involves the development of glossaries for both parts of the classification scheme. The glossary for part-1 Morphology was recently completed and published (Dove et al., 2020). This glossary includes a revised list of feature names, with definitions and representative diagrams for each feature. Feature definitions are in-part drawn from the International Hydrographic Organization (IHO) guide for undersea feature names, which were modified and augmented with additional terms to ensure the final feature catalogue and glossary encompasses the diversity of morphologies observed at the seabed.

Part-2 Geomorphology glossary is now in development. We anticipate it to be more complicated than the Morphology glossary due to the (often) variable meaning of different terms between different fields and individual scientists. But as for Part 1, our primary objective is to produce a useful and robust framework (applicable from the coastal zone to the abyss), that minimises duplication and/or ambiguity as much as possible. The Geomorphology glossary will include example bathymetry images to add further value.

Dove, D., Bradwell, T., Carter, G., Cotterill, C., Gafeira Goncalves, J., Green, S., Krabbendam, M., Mellett, C., Stevenson, A., Stewart, H. and Westhead, K., Scott, G., Guinan, J., Judge, M., Monteys, X., Elvenes, S., Maeten, N., Dolan, M., Thorsnes, T., Bjarnadottir, L., Ottesen, D., 2016. Seabed geomorphology: a two-part classification system. British Geological Survey, Open Report OR/16/001.

Dove, D., Nanson, R., Bjarnadóttir, L.R., Guinan, J., Gafeira, J., Post, A., Dolan, M.F.J., Stewart, H., Arosio, R. and Scott, G., 2020. A two-part seabed geomorphology classification scheme:(v. 2). Part 1: morphology features glossary.
The slip behavior of velocity-weakening fault barriers
Authors: Molina Diego , Ampuero Jean-Paul , Tassara Andres
Published: March 2021

Subduction earthquakes are among the most devastating natural hazards across the planet and yet the factors controlling their size remain poorly understood. It is thus important to investigate the mechanisms controlling rupture arrest and runaway, in particular the nature of rupture barriers (areas where earthquakes tend to stop). Geodetic and seismic observations along several faults suggest that barriers are mostly creeping (low seismic coupling). It is often interpreted that creeping barriers are governed by velocity-strengthening friction (VS), which is a sufficient condition for stable slip. However, some barriers have been observed to host intermediate magnitude earthquakes or to be completely ruptured by a large earthquake. Therefore, the frictional properties of seismic barriers may not be restricted to VS. In particular, the possibility of velocity-weakening (VW) areas behaving as barriers needs to be further explored.

In this work, we characterize the multiple behaviors of seismic barriers on faults governed by velocity-weakening (VW) rate-and-state friction, using earthquake cycle simulations. We consider a 2D model, where a central VW area has a larger critical slip distance (Dc) or higher normal stress (σ) than the surrounding VW areas. We found that the central areas can behave as permanent or temporal barriers to earthquake propagation if their Dc or σ are large enough. On permanent barriers, creep occurs steadily. However, on temporary barriers, the locking degree changes throughout the cycle, despite frictional properties remaining constant.

To understand the efficiency of VW barriers (that is, to determine under what conditions they can stop ruptures), we use fracture mechanics theory. We found that barrier efficiency depends mainly on the ratio between the fracture energy of the barrier, which is proportional to Dc and normal stress, and the energy release rate of the neighboring seismic segment, which is proportional to its stress drop squared and length. If geological features of the overriding and subducting plates affect Dc and σ on the megathrust, our results support the idea of structural controls on the seismic behavior of megathrusts. Thus, understanding how geological features are linked to fracture energy may contribute to seismic hazard assessment by constraining rupture arrest and multi-segment ruptures in earthquake scenarios.
MODELLING THE TERRESTRIAL NITROGEN AND PHOSPHORUS CYCLE IN THE UVic ESCM 
Authors: De Sisto Makcim , MacDougall Andrew
Published: March 2021

The role of nitrogen and phosphorus in terrestrial ecosystems has been shown to be critical in the regulation of the terrestrial carbon cycle. Therefore, the implementation of nutrient limitation in Earth System Models should be considered in order to have a more accurate representation of carbon fluxes, vegetation distribution and the response of the biosphere to climate change. Previous attempts to introduce the terrestrial nitrogen cycle and nutrient limitation in the UVic ESCM resulted in an incomplete project that was not added to the regular structure of the model. Here, we intend to improve the current state of the terrestrial nitrogen cycle and to develop a new terrestrial phosphorus cycle that will be coupled to the carbon cycle. The most prominent changes in the N cycle are the enforcement of N mass conservation and the merge with a deep land surface and a new wetland model. The N and P cycles estimates the fluxes between three organic pools: litter, soil and vegetation compartments (leaf, root and wood), two N pools (NH4+, NO3-) and one inorganic P pool. The basic structure of the N cycle was left in place, it estimates the inputs via biological nitrogen fixation and outputs via leaching, furthermore, with the merger with the new wetland model denitrification was added to the N loss of the system. The P cycle accounts the inputs from estimations of rock weathering and losses from occlusion and leaching. Both cycles regulate the vegetation system in 2 ways: (1) by controlling vegetation biomass if nutrient is limiting, reducing the amount of carbon in the plant compartments until the C:N or C:P ratio is met and (2) directly regulating the primary productivity by taking into account the relationship between leaf N and P and the maximum carboxylation rate (Vcmax). We aim to improve projections of the future CO2 fertilization feedback, and thus carbon budgets and ZEC.
Evacuation shelter suitability modeling under combined geo-hydrological hazards in Western Ghat region, India
Authors: Bera Somnath , Gnyawali Kaushal Raj
Published: March 2021

Geo-hydrological hazards like floods and landslides are common in mountain regions. During a disaster, evacuation shelters become a primary need of people. We develop a model to find suitable locations for emergency shelters in flood and landslide strikes in a rural mountain setting of the Western Ghat region, India. Firstly, susceptibility maps for flood and landslide hazards are prepared using a machine learning (Random forest) algorithm. Then location suitability modeling is done in GIS using the entropy method. The following entropy evolution factors are considered- flood susceptibility, landslide susceptibility, land use, distance from the road, distance from the hospital, distance from the market, distance from the fire station, distance from safe water sources, and the population of settlement cluster area. Model constraining factors like steep slope, high landslide, flood susceptible area, and protected area are accounted for using a cost matrix. The model is compared with community-based suitability mapping and evacuation centers during the past disaster of 2005. The study will contribute towards better disaster-resilient planning of rural mountainous settlements.

Keywords: Evacuation shelter, landslide, flood, random forest, entropy method, GIS
The Galileo satellites DORESA and MILENA and their goals in the field of Fundamental Physics within the Galileo for Science (G4S_2.0) project
Authors: Lucchesi David , Fiorenza Emiliano , Lefevre Carlo , Lucente Marco , Magnafico Carmelo , Peron Roberto , Santoli Francesco , Sapio Feliciana , Visco Massimo
Published: March 2021

The G4S_2.0 (Galileo for Science) project is a new proposal funded by the Italian Space Agency (ASI) and aims to perform a set of measurements in the field of Fundamental Physics with the two Galileo satellites DORESA and MILENA. Indeed, the accurate analysis of the orbits of these satellites — characterized by a relatively high eccentricity of about 0.16 — and of their clocks — the most accurate orbiting the Earth — allows to test relativistic gravity by comparing the predictions of Einstein's theory of General Relativity with those of other theories of gravitation. After a general introduction to the project objectives, we will present the preliminary activities of G4S_2.0 which are being developed by IAPS-INAF in Rome. The results of G4S_2.0 will be particularly useful for the applications of the Galileo FOC satellites in the fields of space geodesy and geophysics as some of these activities will concern the improvement of the precise orbit determination of the satellites through an enhancement of the dynamic model of their orbits, analyzing, in particular, the modelling of non-conservative forces.
Biological soil crusts mediate changes in soil aggregate stability along a climate gradient in Chile
Authors: Riveras Muñoz Nicolás , Seitz Steffen , Gall Corinna , Pérez Hugo , Kuehn Peter , Seguel Oscar , Scholten Thomas
Published: March 2021

Biological soil crusts (biocrusts) composed of cyanobacteria, algae, lichens and bryophytes have a stabilizing effect on the soil surface. This effect is mostly studied in arid climates, where biocrusts are the main biological agent to steady and bind together soil aggregates. Nevertheless, biocrusts are also an integral part of the soil surface under semi-humid and humid climate conditions, mainly covering open spaces in forests and on fallow lands. As such, they often develop after vegetation disturbances, when their ability to compete with higher plants is increased. To better understand how biocrusts mediate changes in soil aggregate stability under different climatic conditions, we analyzed soil substrates taken under biocrust communities from four national parks in Chile using dry and wet sieving. These samples cover soils from a large climate gradient from arid (Pan de Azúcar), semiarid (Santa Gracia), mediterranean (La Campana) to humid (Nahuelbuta). 
Biocrust communities were dominated by cyanobacteria in Pan de Azúcar and Santa Gracia, bryophytes and lichens in La Campana and bryophytes in Nahuelbuta. They showed a stabilizing effect on the soil surface in three of the four investigated climates. Their presence increased the Mean Weight Diameter of the aggregates (MWD) by 102% in Pan de Azúcar, 208% in Santa Gracia and 82% in La Campana. In Nahuelbuta there was no significant increase to the condition without biocrust, because the abundance of permanent soil covering higher vegetation does not allow the effect of biocrusts to manifest. The stabilization differed between the aggregate fractions studied, being most pronounced for smaller aggregates >2 mm. The Geometric Mean Diameter (GMD) showed similar results as MWD, but with a clear effect of drying and wetting conditions, as an increase in the stability directly related to precipitation and the climatic gradient. Bulk density (BD) changed from high mean values of 1.50 g cm-3 in Pan de Azúcar and 1.63 g cm-3 in Santa Gracia (where cattle grazing was observed) to 1.16 g cm-3 in La Campana and the lowest mean of 0.62 g cm-3 in Nahuelbuta, where we observed a more developed soil structure and high organic matter content (21.58% in average). Accordingly, here we also found pronounced hydrophobicity of the soil. These preliminary findings indicate not only differences in the stability of the aggregates, but also in the state of conservation and management of the soils. Results will now be extended by further statistical analyses, which will additionally be presented at vEGU21.
Spatial and temporal variability in PV generation with respect to consumption patterns
Authors: Vulic Natasa , Rüdisüli Martin , Orehounig Kristina
Published: March 2021

In efforts to reduce the carbon intensity of electricity generation, optimizing the use of renewable energy necessitates an understanding of its spatial and temporal variability with respect to the corresponding consumption patterns. Their coupled analysis leads to identifying existing and anticipated discrepancies in supply and demand that can help to guide both the implementation of monitoring and control strategies to balance loads through demand-side management (e.g. shifting space heating, domestic hot water, EV charging) and storage (e.g. battery, thermal, and chemical), as well as plans for further expansion of renewable energy generation. In this study, we analyze PV production and consumption patterns (daily/weekly/seasonal) within and across different utilities for the case study in Switzerland. We analyze three utilities using (1) indicators to assess their PV production and utilization, (2) visualization techniques to observe the varying patterns in consumption and production across day/week/year, and (3) computational methods to balance production surpluses and deficits, estimating the necessary load-shifts for different PV production levels (regardless of the means of shifting this demand). In the first case, we assess balancing areas of different scales---from a handful of prosumers to a residential neighborhood to the full utility area---demonstrating an improvement in their capacity to accommodate higher shares of PV production. We attribute this improvement to reduced variability in aggregated supply and demand, together with the increased diversity in building use (residential, office, retail/restaurant, industrial, etc.). When comparing the production and consumption patterns across the three utilities, similarities in the shapes of the daily profiles, weekday/weekend consumption, seasonal variations (e.g. heating demand) and load-scheduling practices (e.g. domestic hot water charging) are observed. Nevertheless, we observe large differences in their ability to consume the produced PV electricity locally, which appear related to their building stock composition, PV installation types (residential vs commercial), as well as access to higher grid hierarchy levels. These differences demonstrate the need for locally tailored strategies to expand PV production while ensuring their adequate utilization.  The general methods and approach presented here aim to assess these differences and inform more effective implementation strategies needed to reach ambitious national renewable energy targets.
Vulnerability of Swiss lakes to climate change along an altitudinal gradient
Authors: Råman Vinnå Love , Medhaug Iselin , Schmid Martin , Bouffard Damien
Published: March 2021

Studies investigating the influence of 21st century climate warming on lakes along altitudinal gradients has been obscured by complex local atmospheric phenomena, insufficiently resolved by regional climate model grids in mountain regions. Here we used locally downscaled climate models to force the physical lake model Simstrat under three future climate scenarios to investigate the impact on 29 Swiss lakes, varying in size and located along an altitudinal gradient. Results predict significant changes linked to altitude in duration of ice-cover, and stratification. Lower and especially mid altitude lakes risk changes in mixing regimes. A large fraction of previously dimictic lakes shift to a monomictic regime under RCP8.5. Analysis further indicates that for many lakes climate related change can be limited by adhering to RCP2.6.
Identifying evolving/non-evolving plasma bubbles from SWARM observations
Authors: Nayak Chinmaya , Buchert Stephan , Kakad Bharati
Published: March 2021

Equatorial plasma bubbles (EPBs) are generally caused due to the Rayleigh–Taylor instability. During the initial phase of the growth of the instability, the bubbles are associated with perturbation electric and magnetic fields. We call this the evolving (active) phase of the EPB. Over time, these electric field fluctuations decay in amplitude and the bubble, embedded in the neutral atmosphere, drifts eastward without much temporal evolution. We call this the non-evolving phase. Both phases can be distinguished in ground based VHF spaced receiver scintillation observations. In the evolving phase, the cross correlation between the signals from the two receivers is significantly less than one because of rapidly evolving perturbation electric fields. However, after some time (~2 hours) as the perturbation electric field decays, the cross correlation reaches almost 1 implying very slow temporal changes. This technique is applied to identify fresh generation of post-midnight plasma bubbles during magnetically disturbed conditions. From in situ satellite observations, the EPBs are generally identified as sudden depletion from background electron density, associated with magnetic fluctuations. In fact, the plasma bubble index produced from data of the ESA Swarm mission utilizes this same criteria of concurrent density depletions and magnetic fluctuations to identify the plasma bubbles. However, it is not so straightforward to distinguish evolving and non-evolving phases of the plasma bubbles in the SWARM plasma and magnetic observations. We look into near simultaneous in situ observations of SWARM and ground based VHF spaced receiver scintillation to identify a standard criteria for distinguishing evolving/non-evolving bubbles in SWARM observations. The results suggest that the presence/absence of magnetic fluctuations associated with the depletion in electron density can be used as a criteria for evolving/non-evolving bubbles. Ideally, the electric and magnetic field fluctuations should be present simultaneously and as a result should decay simultaneously. We have looked into one year (2014) of SWARM observations of EPBs and VHF spaced receiver scintillation data from Indian equatorial station Tirunelveli. A few case studies during both magnetically quiet and disturbed conditions are discussed.