bluuebunny/crossref_metadata_2025 huggingface dataset:
Coastal Trapped Waves along the Southeast Greenland Coast in a realistic numerical simulation
Authors: Gelderloos Renske , Haine Thomas W. N. , Almansi Mattia
Published: March 2021

Ocean currents along the Southeast Greenland Coast play an important role in North Atlantic circulation and the global climate system. They carry dense water over the Denmark Strait sill, fresh water from the Arctic and the Greenland Ice Sheet into the subpolar ocean, and warm Atlantic water into Greenland’s fjords, where it can interact with outlet glaciers. Observational evidence from the OSNAP array and other mooring records shows that the circulation in this region displays substantial subinertial variability, typically with periods of several days. For the dense water flowing over the Denmark Strait sill, this variability augments the time-mean transport; on the shelf, the variability is large enough to occasionally reverse the mean transport direction of the coastal current, highlighting the importance of characterizing this variability when interpreting synoptic surveys. In this study, we used the output of a high-resolution realistic simulation to diagnose and characterize subinertial variability in sea surface height and velocity along the coast. The results show that the subinertial signals on the shelf and along the shelf break are coherent over hundreds of kilometers, and consistent with Coastal Trapped Waves in two subinertial frequency bands—at periods of 1–3 days and 5–18 days—portraying a combination of Mode I and higher modes waves. Furthermore, we find that northeasterly barrier winds may trigger the 5–18 day shelf waves, whereas the 1–3 day variability is linked to high wind speeds over Sermilik Deep.
New flexible retrieval for gusts and mean winds from Doppler wind lidars
Authors: Steinheuer Julian , Detring Carola , Beyrich Frank , Löhnert Ulrich , Fiedler Stephanie
Published: March 2021

Phenomena in the atmospheric boundary layer are investigated in the Field Experiment on Sub-Mesoscale Spatio-Temporal Variability in Lindenberg (FESSTVaL, www.fesstval.de). Our aim is the retrieval of wind gusts from measurements of a Doppler wind lidar (DWL). DWLs allow the determination of wind vector profiles with high vertical resolution (∼30 m) and represent an alternative to classical meteorological tower observations. They can receive signals from altitudes higher than towers and are flexible in positioning. However, the retrieval of wind gusts from DWL measurements is not trivial because a monostatic lidar provides only one radial velocity, i.e., only one component of a three-dimensional vector, and measurements in three linearly independent directions are necessary to derive the wind vector. These have to be performed sequentially which limits the achievable time resolution, while wind gusts are short-lived phenomena. Therefore, we have developed a new wind retrieval that is applicable to different scanning configurations and various requested time resolutions. We tested several DWL configurations in autumn 2019 using DWL systems ’StreamLine’ from Halo Photonics and evaluated gust peaks and the 10min mean wind at 90 m height against data from a sonic anemometer at the meteorological tower. The most useful configuration for retrieving wind gusts is a fast continuous scan mode (CSM) that completes a full circulation cone within 3.4s. During this time interval, about eleven radial velocity measurements are completed. This fast CSM configuration was again successfully operated over a three-months period in summer 2020. We found that CSM paired with our new retrieval technique provides gusts which compare well to classical anemometer measurements from a meteorological tower. Future work includes the application of the new retrieval to DWL data during the FESSTVaL campaign in 2021 when DWL measurements are planned at different sites in order to study the sub-mesoscale variability of wind gusts.
Evaluation of soil salinity and sodicity using electromagnetic conductivity imaging 
Authors: Farzamian Mohammad , Martinez Moreno Francisco José , Ramos Tiago B. , Castanheira Nadia , Paz Ana Marta , Monteiro Santos Fernando A. , Alexandre Carlos A. , Paz Maria Catarina , Rodríguez Mario Ramos , Vanderlinden Karl , Gonçalves Maria C.
Published: March 2021

In order to prevent further soil degradation, it is important to understand the processes controlling salinization. Salt related problems in soils can refer to an excess of soluble salts (saline soils), a dominance of exchangeable sodium in the soil exchange complex (sodic soils), or a mixture of both situations (saline-sodic soils). These categories are important because the impacts and management vary accordingly. Traditional soil sampling methods –which require boreholes for soil sampling and analysis– difficultly lead to a comprehensive answer to this problem. This is because they cover only small and localized sites and may not be representative of the soil properties at the management scales. Furthermore, they are highly time and work consuming, resulting in costly surveys. Geophysical techniques such as electromagnetic induction (EMI) provide enormous advantages compared to soil sampling because they allow for in-depth and non-invasive analysis, covering large areas in less time and at a lower cost.

EMI surveys were performed in several regions in Portugal with historic soil salinity and sodicity problems to evaluate the salinization risk. We inverted field apparent conductivity data (σa) in order to obtain electromagnetic conductivity images (EMCI) of the real soil electrical conductivity (σ) in depth. We evaluated the potential of EMCI in the estimation of soil salinity, sodicity, and other soil properties over large areas across regions with a very different range of salinity and sodicity.

 

Acknowledgments

This work was developed in the scope of SOIL4EVER “Sustainable use of soil and water for improving crops productivity in irrigated areas” project supported by FCT, grant no. PTDC/ASP-SOL/28796/2017.

 
Co-occurrence network inference analysis allows identification of keystone microbial species associated to soil compartments and environments in cultivated olive
Authors: Anguita-Maeso Manuel , Estudillo-Cazorla Cristina , León-Ropero Guillermo , Navas-Cortés Juan A. , de Menezes Alexandre , Landa Blanca B.
Published: March 2021

Large-scale microbiome studies are currently facing challenges to overcome the lack of knowledge in relation to the interactions occurring among microbial communities and their surrounding environment. As a result, the study of associations through co-occurrence network analysis may lead to a better understanding for the aggregation or exclusion interactions in microbial studies and it offers a mapping of how information flows among the members of the microbiome system. By using 16S and ITS high-throughput sequencing, we studied the associations of bacterial and fungal communities in different olive compartments (fruit, phyllosphere, stem, xylem sap and roots) and the surrounding soil (bulk and rhizosphere) from three olive genotypes (‘Picual’, ‘Arbequina’ and ‘Frantoio’) growing at three olive orchards (Úbeda, Baena and Antequera) which differ in physicochemical soil characteristics and climate, in Andalusia, Southern Spain. Results based on the analysis of amplicon sequence variant (ASVs) displayed distinct microbial association network behaviors according to plant or soil compartments. Thus, plant compartment showed a positive association between Actinobacteria and Proteobacteria whereas some negative associations were exhibited by fungal communities, mainly from phyla Ascomycota and Basidiomycota. On the other hand, the negative associations of fungi were more noticeable in the soil compartments and the bacterial phylum Firmicutes played a different role in the soil than in the plant compartments. Furthermore, members of the bacterial phyla Deinococcota and Armatimonadota were unique in plant compartments while the phylum Verrucomicrobiota was only detected in the soil compartment. Overall, 14 keystone species with positive and negative associations in aboveground and belowground compartments were predicted based on the network parameters of high closeness and degree, and a low betweenness centrality. Interestingly, Bradyrhizobium and Pseudonocardia were positioned as two common keystone species among the positive associations in both compartments. This powerful analysis can reveal new knowledge regarding specific microbial associations on soil and plant microbiomes and it can propose a possible road map to investigate potential microbial source migration from soil to olive compartments.

 

Study supported by Projects XF-ACTORS 727987 (EU-H2020) and AGL2016-75606-R (MICINN Spain and FEDER-EU). MA-M acknowledged the predoctoral contract for the Training of Personal Investigator (FPI- MICINN) with reference BES-2017-082361 and COST Action CA16107 EuroXanth.
Assessing fluvial flooding hazard with a DEM-based Hierarchical Filling-&-Spilling Algorithm: a case study in Northern Italy 
Authors: Persiano Simone , Carisi Francesca , Wang Huimin , Luzzi Valerio , Mazzoli Paolo , Bagli Stefano , Castellarin Attilio
Published: March 2021

The steady increase of economic losses and social consequences caused by flood events in Europe is triggering the development of updated and efficient technologies for assessing flood hazard over large areas, where detailed hydrologic-hydrodynamic numerical models are resource intensive and therefore scarcely suitable. In this context, the EIT-Climate KIC SaferPLACES (https://saferplaces.co) project aims at exploring and developing innovative and simplified modelling techniques to assess and map pluvial, fluvial and coastal flood hazard and risk under current and future climates, mainly based on LiDAR (Light Detection And Ranging) high-resolution DEMs (Digital Elevation Models) raster-based analysis. Within the SaferPLACES activities, a fast-processing Hierarchical Filling-&-Spilling Algorithm (HFSA), named Safer_RAIN (see Samela et al., 2020; https://www.mdpi.com/2073-4441/12/6/1514/htm), has been recently developed for mapping pluvial flooding in large urban areas by accounting for spatially distributed rainfall inputs and infiltration processes. Although it does not incorporate any detailed description of the dynamics of overland flow and water-depth routing, previous applications have shown Safer_RAIN to be an effective tool for a rapid and consistent identification of pluvial-hazard hotspots under different rainfall and land-use scenarios.

Although Safer_RAIN has been conceived for pluvial flooding hazard assessment, its structure suggests its suitability for delineating flooded areas and computing water depth in the aftermath of fluvial inundation (i.e. once the dynamic components of the inundation process become negligible) in predominantly flat floodplains. To this aim, a given flood volume can be assigned to the pixels coinciding with the fluvial flooding point-sources (e.g. simulated levee breach or overtopping) as the input to Safer_RAIN, which is then used for flooding the downstream floodplain portion according to a HSFA approach. We present a first test of the fluvial-application of Safer_RAIN for the case study of the Pisciatello river (Northern Italy, floodplain area of approximately 1300 hectares). Results for different flood scenarios obtained with Safer_RAIN at 1m resolution are compared with the corresponding flooding scenarios simulated with the fully two-dimensional numerical model HEC-RAS at 1m and 5m resolutions. The outcomes of both models are compared in terms of flooded area extent and water depth distribution, highlighting potential and limitations of Safer_RAIN for identifying fluvial flooding hazard.
Tropospheric impact of Sudden Stratospheric Warmings in Central and Eastern Europe
Authors: Hrițac Robert , Sfîcă Lucian , Ichim Pavel
Published: March 2021

The North Hemisphere winter stratosphere is frequently affected by large and rapid temperature increases, known as Sudden Stratospheric Warmings (SSWs). The strongest and most spectacular events, known as the Major Mid-Winter Warmings, cause a temporary reversal of climatological westerly zonal mean winds and, in some cases, even the breakup of the stratospheric polar vortex into several smaller vortices. The following downward propagation of stratospheric anomalies to the upper and middle troposphere has been associated with significant weather anomalies resembling a negative Northern Annular Mode (NAM) regime over Eurasia and North America. These events are often involved in winter weather extremes in Northern Hemisphere, therefore a better understanding of their occurrence and development could be helpful for the improvement of medium term forecast of extreme meteorological conditions.

In order to assess the impact of Sudden Stratospheric Warmings on surface weather conditions in central and eastern Europe, all major SSW events identified in the period 1979 – 2020 were classified in 5 major types using a k-means cluster analysis method. Then, in order to determine the changes in tropospheric circulation as an effect of each SSW, we identified the main weather circulation types in Europe by performing a cluster analysis of 500 hPa geopotential height and sea level pressure. After that, the changes in frequencies of these types, as well as the mean composite anomalies of the two aforementioned parameters were assessed. This has been done for three intervals: one month before and two months after a SSW event. The surface and lower troposphere impact was studied using the mean composite anomalies of several parameters: 2 m temperature, total precipitation amount, snowfall and snow depth, for the same intervals.

 The results show a great deal of variability in the surface effects of SSW events. The general impact of SSW events consisted in a tendency towards a diminishing of the frequency of westerlies, and a subsequent increase in the frequency of both Mediterranean cyclones and high latitude blocking conditions, with their associated temperature and precipitation anomalies. Also, a second major output of the study indicates that in central and eastern Europe these SSW events lead to harsh winter conditions in 30% of cases, but also to abnormal warm winters intervals in other 25% of cases, depending on the type of the SSW. However, some events show a less marked impact on tropospheric weather, while other SSW do not propagate from the stratosphere to the upper and middle troposphere. Taking into account the type and characteristics of each SSW might significantly increase the predictability of their tropospheric effects.
Shear-wave seismic reflection processing - the importance of velocity analysis
Authors: Dietiker Barbara , Pugin André J.-M. , Griffiths Matthew P. , Brewer Kevin , Cartwright Timothy
Published: March 2021

Based on our experience, one of the most important steps in processing shear-wave seismic reflection data is the velocity analysis. In unconsolidated materials a very fine velocity analysis is more essential for S-waves than for P-waves because shear-wave velocities vary over several orders of magnitude and can change very quickly laterally and with depth. Velocities between 100m/s in glaciolacustine/marine deposits (clay-sized silts) and 1200m/s in stiff diamicton (till) were encountered in recent surveys. Shear-wave velocities have the large advantage of not being changed by the phase of the pore content such as the groundwater table.

We present two fundamentally different methods for velocity determination: 1) velocity semblance analysis based on hyperbolic reflection move-out on common midpoint (cmp) gathers and 2) Local Phase – Local Shift (LPLS) method which automatically estimates the reflection slope (local static shift) in the time-frequency domain of cmp gathers. Published in 2020, the latter method can be used for automated processing and substantially saves processing time.

Processing steps in preparation for velocity analysis (independent of the chosen method) include frequency filtering, trace equalizing and muting. We show velocity semblance images from different geological settings (glacial, postglacial) and from different shear components and discuss differences. Information gained besides shear velocities include mapped reflectors and located diffractions. Using those examples, we demonstrate how combining all information using visualisation techniques enhances interpretation of such data sets.
Unraveling seasonal carbon-limitation of benthic nitrate-reduction in the coastal Baltic Sea
Authors: Hellemann Dana , Aalto Sanni-Leea , Asmala Eero , Jilbert Tom , Kiljunen Mikko , Koch Boris , Norkko Joanna , Norkko Alf
Published: March 2021

Excess bioavailable nitrogen (N) is the key driver of coastal eutrophication, thus knowledge on the fate of N in coastal systems is imperative for improving eutrophication mitigation measures. In the coastal Baltic Sea, benthic heterotrophic denitrification, the main process of bioavailable N-removal from a coastal system, has recently been suggested to be seasonally limited by labile organic carbon (OC) availability1 - despite the system´s richness in labile organic matter from long-term eutrophication. This challenges our common understanding of the intrinsic link between C- and N-cycling, and highlights the need for a more advanced concept of OC availability. Hence, in this project, we (i) extensively characterized the biochemical composition of coastal OC beyond traditional descriptors of ‘lability’, applying techniques such as isotopic fingerprinting and Fourier transform ion cyclotron resonance mass spectrometry, and (ii) concurrently quantified benthic nitrate reduction rates both with and without addition of easily degradable OC (glucose), to ultimately confirm and understand proposed OC-limitation of denitrification in coastal sediments. All measurements were done in high temporal and spatial resolution at the southern coast of Finland, covering a three-month period from late winter to early summer that included the peak annual input of fresh organic matter to the benthic system by the phytoplankton spring bloom. First results will be presented and their implications for understanding seasonal N turnover and coastal eutrophication dynamics will be discussed.

1Hellemann D, Tallberg P, Aalto SL, Bartoli M, Hietanen S (2020) Seasonal cycle of benthic denitrification and DNRA in the aphotic  coastal zone, northern Baltic Sea. Mar Ecol Prog Ser 637:15–28
The epicentral fingerprint of earthquakes
Authors: Petricca Patrizio , Bignami Christian , Doglioni Carlo
Published: March 2021

InSAR images allow to detect the coseismic deformation, delimiting the epicentral area where the larger displacement has been concentrated. The main observations are: 1) the most deformed area in the ideal case is elliptical (for dip-slip faults) or quadrilobated (for strike-slip faults) and coincides with the surface projection of the volume coseismically mobilized in the hanging wall of thrusts and normal faults, or the crustal walls adjacent to strike-slip faults; 2) the dimension of the deformed area detected by InSAR scales with magnitude of earthquake and for M≥6 is always larger than 100 km, increasing to more than 550 km2 for M≈6.5; 3) the seismic epicenter rarely coincide with the area of larger vertical shaking (either downward or upward); 4) the higher macroseismic intensity corresponds to the area of larger vertical displacement, apart from local site amplification effects; 5) outside this area, the vertical displacement is drastically lower, determining the strong attenuation of seismic waves and the decrease of the peak ground acceleration in the surrounding far field area, apart from local site amplifications; 6) the segment of the activated fault constrains the area where the vertical oscillations have been larger, allowing the contemporaneous maximum freedom degree of the crustal volume affected by horizontal maximum shaking, i.e., the near field or epicentral area; 7) therefore, the epicentral area and volume are active, i.e., they coseismically move and are contemporaneously crossed by seismic waves (active volume), whereas the surrounding far field area is mainly fixed and passively crossed by seismic waves (passive volume). Therefore, here we show how the InSAR images of areas affected by earthquakes represent the fingerprint of the epicentral area where the largest shaking has taken place during an earthquake. Seismic hazard assessments should rely on those data.
How to tackle spatial variability and temporal non-linearity in land subsidence in unconsolidated coastal environments?
Authors: Minderhoud Philip S.J. , Zoccarato Claudia , Xotta Riccardo , Teatini Pietro
Published: March 2021

Accurate land subsidence quantifications are of growing importance as relative sea-level rise in unconsolidated coastal environments is increasingly dominated by subsidence. Land subsidence, especially in unconsolidated settings, is the result of a complex interplay and sum of a range of different subsurface processes. As these processes can be spatially and temporally very variable, it requires more than (point and/or land surface) measurements to accurately quantify subsidence, especially when projections of subsidence are required for example to assess future relative sea-level rise. This requires first of all a thorough understanding of subsidence drivers and subsurface processes in a 4D perspective (3D including time) and secondly data interpretation methods and tools to handle the complex coupling of these interrelated processes to enable spatial-temporal quantification and projection of coastal subsidence.

We present a set of novel approaches, with which we aim to move our capacity to accurately capture and simulate the highly dynamic behaviour of subsidence processes. The approaches range from novel field experiments to advanced interpretation of sedimentary information in coastal-deltaic setting to gain important input for numerical modelling, and to newly-developed state-of-the-art 3D numerical simulators. Through these combined methodologies we aim to improve our capacity to assess both natural subsidence processes, like natural compaction, and anthropogenic-induced processes, like aquifer-system compaction following overexploitation in unconsolidated settings. This will ultimately contribute, for example through scenario modelling of anthropogenic drivers, to create reliable future projections of land subsidence which will enable sound projections of relative sea-level rise.
Multi-year predictability of Colorado River water supply using a drift-free decadal climate prediction system
Authors: Chikamoto Yoshimitsu , Wang Simon , Yost Matt , Yocom Larissa , Gillies Robert
Published: March 2021

Skillful multi-year climate forecasts provide crucial information for decision-makers and resource managers to mitigate water scarcity. Yet, such forecasts remain challenging due to unpredictable weather noise and the lack of dynamical model capability. In this research, we demonstrate that the annual water supply of the Colorado River in the United States is predictable up to several years in advance by a drift-free decadal climate prediction system using a fully coupled climate model. Observational analyses and model experiments show that prolonged shortages of water supply in the Colorado River are significantly linked to sea surface temperature precursors, including tropical Pacific cooling, North Pacific warming, and southern tropical Atlantic warming. In the Colorado River basin, the water deficits can reduce crop yield and increase wildfire potential. Thus, a multi-year prediction of severe water shortages in the Colorado River basin could be useful as an early indicator of subsequent agricultural loss and wildfire risk.
Below the Mosul Dam Lake. Geomorphological reconstruction of historical fluvial pattern of the Tigris River 
Authors: Forti Luca , Pezzotta Andrea , Regattieri Eleonora , Mariani Guido Stefano , Brandolini Filippo , Zerboni Andrea
Published: March 2021

Located along the Tigris River in the Kurdistan Region of Iraq (KRI), the Mosul Dam reservoir is the second biggest dam of the Near East, and represents an important water storage for local human activities. The Dam was built between 1981 and 1988 north of the village of Eski Mosul; along this part of the Tigris River several archaeological sites were inundated. Analysis of historical images derived from Declassified Corona satellite acquired between December 1967 and August 1968 reveals seasonal changes of the Tigris riverbed, shifting across the hydrological year from meandering to anastomosing. The geomorphological mapping was carried out on the December 1967 and. in August 1968, Corona images were taken, in order to estimate the modification of several fluvial geomorphological elements such as floodplain and point, middle and longitudinal bars. Here, such evidence is compared with Landsat data collected between the 1990ies and today, in order to detect the first phases of filling of the basin and the control of inherited Tigris channel belt over the reservoir. Moreover, we also noticed an influence of the ancient Tigris course on is recent insertion into the lake. Our work permitted to reconstruct the ancient fluvial landscape below the Mosul Dam Lake, and its evolution in response to seasonal variation of the discharge.
Ion and electron energization by Alfvén waves in magnetic shears
Authors: Pucci Francesco , Bacchini Fabio , Lapenta Giovanni , Malara Francesco
Published: March 2021

In order to efficiently convert AW energy into particle energy, the original fluctuation must decay from the initial macroscopic (fluid) scales to smaller (kinetic) scales. This decay can be promoted by the interaction of counter-propagating AWs or by the interaction between AWs and an inhomogeneous background. It has been shown that AWs interacting with an inhomogeneous background can cascade to smaller scales via the phase-mixing process [1]. When the cascade reaches scales comparable with the ion Larmor radius, AWs can efficiently be converted into ”kinetic” Alfvén  waves (KAWs), which represent the natural extension of AWs in the kinetic branch of the wave dispersion relation for wavevectors nearly perpendicular to the background magnetic field [2]. In this work we present the results of a numerical experiment in which the decay of AWs into KAWs is studied self-consistently in a range that goes from fluid to kinetic electron scales. We show how the AW-to-KAW transition, promoted by an inhomogeneous background, leads to the heating of both ions and electrons via two different physical mechanisms. Both mechanisms are illustrated via a simple argument on how the two species can access the kinetic and magnetic energy carried by AWs. Our findings are supported by in-situ observations of KAWs in the Earth’s magnetosphere [3].

[1]  J. Heyvaerts  and  E.  Priest,  Coronal  heating  by  phase-mixed shear Alfv ́en waves, Astronomy and Astrophysics117, 220 (1983).
[2]  J. Hollweg, Kinetic Alfv ́en wave revisited, Journal of Geo-physical Research:  Space Physics104, 14811 (1999)
[3] D. Gershman, F. Adolfo, J. Dorelli, S. Boardsen, L. Avanov, P. Bellan, S. Schwartz, B. Lavraud, V. Cof-fey, M. Chandler,et  al., Wave-particle energy exchangedirectly observed in a kinetic Alfv ́en-branch wave, Naturecommunications8, 1 (2017).
Crabby’s Reef - Using games to bring people closer to the issue of ocean acidification
Authors: Roggatz Christina C. , Skinner Christopher J.
Published: March 2021

Ocean acidification is often referred to as climate change’s hidden evil twin. As the world’s oceans partly absorb the carbon dioxide that humans are pumping into the planet’s atmosphere, the oceans’ pH decreases, making the water more acidic. This comes with a range of negative consequences, one of them being the recently uncovered impairment of the sense of smell of marine animals like fishes and crabs.

Awareness of ocean acidification, including its impacts on marine life, however, is low amongst the public. It is something that is viewed as remote to peoples’ lives, happening a long distance away and not for a long time into the future. It is important we take action now as a society to curb climate change and reduce the potential impacts of ocean acidification. Raising awareness and helping to make an emotional connection to the issue is a first step on this journey.

In Crabby’s Reef we use the power of gaming to enable players to experience the impact of this invisible and abstract process of ocean acidification. Inspired by classic arcade games, it puts players into the metaphorical shoes of Crabby, the crab. They navigate daily life on the ocean floor, guiding Crabby through the maze-like reef, seeking food and avoiding predatory octopuses who would make Crabby dinner. With each new level, you are transported to a more acidic future, your senses dampened by blurring the screen, reflecting Crabby’s loss of ability to smell the food.

With life getting harder, we ask how long can you survive?

Play the game here - https://seriousgeo.games/activities/crabbysreef/
Data Rescue and Homogenization of Historic Mass Balance Measurements on Swiss Glaciers
Authors: Geibel Lea , Kurzböck Claudia , Huss Matthias , Bauder Andreas
Published: March 2021

Long-term glacier monitoring in Switzerland has resulted in some of the longest and most complete data series globally. Point mass balance observations, starting in the 19th century, are the backbone of the monitoring as they represent the raw and original data demonstrating the response of surface accumulation and melt to changes in climate forcing. Some of these time series on Swiss glaciers provide over 100 years of continuous measurements.

In the past, the variety of sources of historic measurements has only been partially investigated and never been completely and systematically processed and documented. Therefore, a new format for a point mass balance database was developed that allows full traceability of all measurements back to their original source as well as indicators for the quality of the data and corresponding measuring uncertainties. All previously included data sources were transferred into the new data base format and the original sources were re-assessed to validate or correct the entries and identify metadata. Furthermore, newly investigated measurements were added to the data base. The sources of data include an extremely diverse field from over 140 years of measurements such as published reports or studies, unpublished documents from field projects, field notes, digital sources as well as metaknowledge of the observers. Currently, data series with complete metadata for about 60 individual glaciers are available, corresponding to almost 60.000 point observations, one third of which are newly added.

In addition to extending the data base, this project also allowed us to systematically and homogenously fill in missing information such as estimates of the surface elevation of the measurement points and snow/firn density.  In the past, these density values often had to be assumed without actual measurements but those assumptions could vary up to 20% within different projects and assumptions were rarely flagged as such. The newly added metadata now allows performing an analysis of all actually measured density values and a homogenous interpolation of missing values across all times series based on known values. Furthermore, a system to estimate uncertainties of the mass balance measurements based on the metadata was developed as the accuracy of measurements between different measuring techniques and projects with very differing scientific objectives over a time frame of 140 years can vary significantly and therefore needs to be assessed. This quality-checked and complete data base now permits the re-analysis of consistent time series of glacier-wide mass balance allowing further interpretation of the climate change impacts on Swiss glaciers.
From moderate earthquakes to continuous aseismic slip, a variety of ways to release strain along the Chaman fault (Pakistan, Afghanistan). 
Authors: Dalaison Manon , Jolivet Romain , van Rijsingenn Elenora
Published: March 2021

Surface fault slip can be continuously monitored at fine spatial resolution from space using InSAR. Based on 5 years of observations (2014-2019), we describe and interpret the InSAR time series of deformation around the Chaman fault, a major strike-slip fault along the boundary between the Indian and Eurasian plates. Aseismic slip was observed on two >100 km long segments, reaching a maximum of 1 cm/yr. In between, a fault segment delimited by a restraining and releasing bend in the fault trace hosted three Mb 4.2, Mw 5.1 and Mw 5.6 earthquakes in our observation period. These earthquakes were followed by significant postseismic slip with characteristic duration between 1.5 to 3 years. Postseismic to coseismic surface slip ratios reach at least 0.6-1.2. In addition, aseismic slip was observed in close spatio-temporal relationship with those earthquakes. Finally, we argue that we detect numerous micro-slip events of Mw<3, although with large uncertainty. We provide an extensive description of the various modes of slip along this plate boundary fault and discuss the mechanical implications of such entangled behavior. 
Towards a better understanding of river dynamics in semi-urbanised areas: a machine learning analysis on time-series satellite images
Authors: Cislaghi Alessio , Fogliata Paolo , Morlotti Emanuele , Bischetti Gian Battista
Published: March 2021

River channels and floodplains have been highly modified over the last 70 years to mitigate flood risk and to gain lands for agricultural activities, settlements and soft infrastructures (e.g., cycle paths). River engineering measures simplified the geomorphologic complexity of river system, usually from braided or wandering channels to highly-confined single-thread channel. Meanwhile, rivers naturally adjust and self-organise the geomorphologic function as response of all the disturbances (e.g., flood events, river-bed degradation, narrowing, control works) altering sediment and water transfer, exacerbating bank erosion processes and streambank failures, and exposing bare sediment that can be subsequently colonized by pioneer species. In this context, river management has to address river dynamics planning sustainable practices with the aim to combine hydraulic safety, river functionality, and ecological/environmental quality. These actions require the detection of river processes by monitoring the geomorphological changes over time, both over the active riverbank and the close floodplains. Thus, remote sensing technology combined with machine learning algorithms offers a viable decision-making instrument (Piégay et al., 2020).

This study proposes a procedure that consists in applying image segmentation and classification algorithms (i.e., Random Forest and dendrogram-based method) over time-series high resolution RGB-NIR satellite-images, to identify the fluvial forms (bars and islands), the vegetation patches and the active riverbed. The study focuses on three different reaches of Oglio River (Valcamonica, North Italy), representative of the most common geomorphic changes in Alpine rivers.

The results clearly show the temporal evolution/dynamics of vegetated and non-vegetated bars and islands, as consequence of human and natural disturbances (flood events, riparian vegetation clear-cutting, and bank-protection works). Moreover, the procedure allows to distinguish two stages of riparian vegetation (i.e., pioneer and mature vegetated areas) and to quantify the timing of colonization and growth. Finally, the study proposes a practical application of the described methodology for river managers indicating which river management activity (including timing, intensity and economic costs) is more appropriate and sustainable for each studied reach.

 

References: Piégay, H., Arnaud, F., Belletti, B., Bertrand, M., Bizzi, S., Carbonneau, P., Dufour, S., Liébault, F., Ruiz‐Villanueva, V. and Slater, L.: Remotely sensed rivers in the Anthropocene: state of the art and prospects, Earth Surf. Process. Landf., 45(1), 157–188, https://doi.org/10.1002/esp.4787, 2020.
Tropical Cyclone and Easterly Wave Relationship in Regional Precipitation over the Tropical and Subtropical North America
Authors: Dominguez Christian
Published: March 2021

Tropical cyclones (TCs) and easterly waves (EWs) produce significant seasonal rainfall over the tropical and subtropical North America. When TC activity over the tropical eastern Pacific (TEP) or the Intra Americas Seas (IAS) is below-normal (above-normal), regional precipitation may be below (above-normal). However, it is not only the number of TCs what may change seasonal precipitation, but the trajectory of the systems. TCs induce intense precipitation over continental regions if they are close enough to shorelines, for instance, if the TC center is located less than 500 km-distant from the coast. However, if TCs are more remote than this threshold distance, the chances of rain over continental regions decrease, particularly in arid and semi-arid regions. In addition, a distant TC may induce subsidence or produce moisture divergence that inhibits, at least for a few days, convective activity farther away than the threshold distance.

EWs can produce up to 50% of seasonal rainfall and contribute substantially to interannual regional rainfall variability. An observational analysis shows that the El Niño Southern Oscillation (ENSO) affects EW frequency and therefore, their contribution to seasonal rainfall. In recent years, TC activity over the Main Development Region (MDR) of the tropical North Atlantic has a negative impact on regional seasonal precipitation over northern South America. High TC activity over MDR corresponds to below-normal precipitation because it reduces the EW activity reaching northern South America through the recurving of TC tracks. Recurving TC tracks redirect moisture away from the tropical belt and into the mid-latitudes. However, this relationship only holds under neutral ENSO conditions and the positive phase of the Atlantic Multidecadal Oscillation. A 10-member regional model multi-physics ensemble simulation for the period 1990–2000 was analyzed to show the relationships are robust to different representations of physical processes. This new understanding of seasonal rainfall over the tropical Americas may support improved regional seasonal and climate outlooks.
Data-In-Image: a novel concept for data manipulation and encryption implementation
Authors: Abdelwahed Mohamed
Published: March 2021

Conventionally, the way of storing and exchange numerical data depends mainly on binary data files in compressible form. In this era of the Big Data and machine learning systems and with the accumulation of data with different forms and types, it is important to find an alternative way for handling the data. The binary data are software dependent which does not exhibit its content and type without accessing the data by the proper software. In addition, it does not have any encryption ability. To solve this issue, we propose a new concept to handle the digital data in a descriptive, encrypted, compressed form, and able to be previewed. The idea is to pack the binary bits into a bitmap image with specific coding scheme. This approach employs the Steim scheme as a primary compression tool with a 128-bit encryption method then packs the encrypted codes into a WebP image file. The WebP image is featured by being an independent, web friendly, and highly compressed file. In order to make the file describing its contents, we reserved some pixels as coded descriptive pixels. By this way, the now packed data exhibits its contents and type during image preview.

It is proven that the Data-In-Image format, regardless of being encrypted, occupies the least amount of storage space among other image formats that can be easily handled, stored, and shared through clouds and devices safely with a lower cost. For seismic data,  the size of the WebP image comprises ~20% of the corresponding binary size with a bit-rate of ~5.6 b/s which is smaller than that of the Steim form, 27% and 8.9 b/s, respectively. Regarding the compression speed, it is found that the code compresses data with a rate of ~11,118 samples/s or ~ 44 Kbytes/s in average.

In addition, the data image is able to be digitally scanned and with some modifications can be remotely accessed like the quick response code, the thing that is not possible in the binary form. Moreover, the descriptive pixels in the image allow the implementations of smart tools to archive and classify data by machine learning and recognition algorithms.
Multiyear Dynamics of Remotely Mapped Characteristics of Ecosystems in Northern Eurasia 
Authors: Gornyy Victor , Kiselev Andrei , Kritsuk Sergei , Latypov Iscander , Tronin Andrei
Published: March 2021

The climate change of the last decades has to be reflected in the ecosystems dynamics. By investigating the ecosystem dynamics one can get the information about climate change. One of the most suitable source of information about ecosystem dynamics is remote sensing satellite data. We used EOS multispectral images, gravimetric data of the GRACE satellite, and AURA satellite contents of sulfur dioxide data for the period of the last ~20 years. Daily and 8 days composites of different quantitative characteristics, reduced to the spatial resolution 1x1 km, were retrieved from standard products and raw data: - the daily averaged land surface temperature; - the duration of vegetation (the period of year when a land surface temperature is higher than +10oC); - the Enhanced Vegetation Index (EVI); - the effective water layer thickness (EWLT) according satellite gravimentry); - the concentration of sulphur dioxide in atmosphere. The speed of each characteristics change was estimated and mapped by using linear regression. As the result, the regular chain of isometric domains of land surface temperature rising and decreasing was noticed from the West edge to the East edge of Northern Eurasia. The presence of this chain was the reason to express hypothesis about more complex structure of the modern atmospheric circulation and interaction between the Ferrel and the Polar cells. Additionally we have noticed that domain of the land surface temperature growth at the Northern part of West Siberia coincides with decreasing of EWLT. We interpreted this phenomena as result of permafrost degradation.
A century of otolith-derived temperature exposure of Icelandic and Norwegian cod (Gadus morhua)
Authors: von Leesen Gotje , Bogstad Bjarte , Hjörleifsson Einar , Ninnemann Ulysses S. , Campana Steven E.
Published: March 2021

Increasing water temperatures are predicted around the globe with high amplitudes of warming in Subarctic and Arctic regions where Atlantic cod (Gadus morhua) populations currently flourish. We reconstructed population abundance, oxygen isotope and temperature chronologies from otoliths of the two largest cod populations in the world - the Icelandic and the Northeast Arctic (NEA) cod - to determine if their temperature selectivity over the last 100 years was driven by rising water temperatures and/ or changes in abundance. For δ18Ootolith analysis, individual annual growth increments from immature and mature life history stages of cod collected in southern Iceland and the Lofoten area (Norway) were micromilled from adult otoliths. Ambient temperatures of Icelandic and Norwegian cod were reconstructed using otolith δ18O. Linear mixed effect models were applied to identify and quantify the density-dependent temperature selectivity of both cod populations. The results indicated that Icelandic cod migrated into warmer waters with increasing abundance (p < 0.05), whereas NEA cod moved into colder waters (p < 0.001). The temperature selectivity of NEA cod was also significantly correlated with water temperatures at 0-200 m depth (p < 0.001), indicating that NEA cod were at least partially exposed to increasing ocean temperatures due to global warming. Stable oxygen isotope and ambient temperature chronologies can be an important tool for sustainable management plans in terms of future global warming as it can be used to predict re-distribution as oceans warm.
Timescales of plutonic-subvolcanic-volcanic connection in a Mio-Pliocene long-lived igneous system (Tuscany): zircon CA-ID-TIMS dating
Authors: Paoli Gabriele , Dini Andrea , Ovtcharova Maria , Rocchi Sergio
Published: March 2021

The genetic link between plutonic and volcanic realms is a key for understanding timescales of igneous plumbing systems, and precise geochronological records are pivotal in estimating the duration of processes at different levels in such plumbing systems. The Campiglia igneous complex, Tuscany, offers exposures of the full range of emplacement levels (plutonic, subvolcanic, volcanic) of mantle- and crust-derived magmas. Magma emplacement occurred astride the Miocene-Pliocene boundary. New high-precision U-Pb CA-ID-TIMS, zircon geochronological data, coupled with LA-HR-ICP-MS zircon dates for the whole Campiglia system define a short crystallization time span for zircon from the peraluminous granite pluton (~100 ka), intermediate for the shallow-level mafic porphyry (~450 ka), and longer for the rhyolite (~700 ka), at odd with what commonly expected. The oldest ages for the three units are the same, leading to hypothesize the occurrence of a bimodal deep reservoir remaining in melt-present conditions for some 700 ka. In this framework, early-crystallized zircons were cannibalized by younger melt batches that were sequentially extracted from the reservoir.
Automation of Ice Fractures and Calving Events Monitoring Using Medical Imaging Ridge Detection Algorithms
Authors: Glaude Quentin , Lizin Stéphane , Barbier Christian , Pattyn Frank , Orban Anne
Published: March 2021

Ice shelves, i.e. the floating extension of the AIS, are playing an active role in controlling ice loss from the Antarctic ice sheet. Laterally constraint in embayment or by ice rises, they are participating as regulators of the ice discharge, by exerting a back stress to the ice flow. When losing mass, these ice shelves lose their gatekeeper property, with potential local destabilization of the AIS. Losing mass from calving is a sophisticated process that is rarely coupled with observations in ice sheet models. However, calving and damages are visible in SAR remote sensing products. In this study, we built the hypothesis that state-of-the-heart ridge detection techniques from the medical imaging field can be transposed to the cryosphere field. Looking at the local Hessian matrix in SAR acquisitions, we analyzed the eigenvectors that indicate the presence of ridges. Over ice shelves, these edges correspond to the calving front of the ice shelf, or crevasses. Using time series, we can monitor the evolution of crack propagation and calving events. Results over Pine Island Glacier and the Brunt Ice Shelf show a precise delineation of calving events, as well as the damaged areas. These encouraging results support the idea of the integration of ice damage detection from SAR remote sensing into ice sheet models.