bluuebunny/crossref_metadata_2025 huggingface dataset:
The quality analysis of GNSS observations tracked by Android smart devices and positioning performance assessment
Authors: Paziewski Jacek , Fortunato Marco , Mazzoni Augusto , Odolinski Robert , Li Guangcai , Debelle Mathilde , Warnant René , Gong Xiaopeng
Published: March 2021

This study assesses the quality of multi-constellation GNSS observations of selected Android smartphones namely Huawei P30, Huawei P20 and Huawei P Smart as well as Xiaomi Mi 8 and Xiaomi Mi 9. We investigate the properties of phase ambiguities to anticipate the feasibility of precise positioning with integer ambiguity fixing. The results reveal a significant drop of smartphone carrier-to-noise density ratio (C/N0) with respect to geodetic receivers and discernible differences among constellations and frequency bands. We show that the higher the elevation of the satellite, the larger discrepancy in C/N0 between the geodetic receivers and smartphones. We depict that an elevation dependence of the signal strength is not always the case for the smartphones. We discover that smartphone code pseudoranges are noisier by about one order of magnitude as compared to the geodetic receivers, and that the code signals on L5 and E5a outperform these on L1 and E1, respectively. It was shown that smartphone phase observations are contaminated by the effects that can destroy the integer property and time-constancy of the ambiguities. The long term drifts were detected for GPS L5, Galileo E1, E5a and BDS B1 phase observations of Huawei P30. To isolate the observational noise from low frequency effects we take advantage of time differencing using the variometric approach. These investigations highlight competitive phase noise characteristics for the Xiaomi Mi 8 when compared to the geodetic receivers. We also reveal poor phase signal quality for the Huawei P30 smartphones related to the unexpected long-term drifts of the phase signals. The observation quality assessment is supported with the evaluation of a positioning performance. We proved that it is feasible to obtain a precise solution in a smartphone to smartphone relative positioning mode with fixed ambiguities. Such results move us towards a collaborative precise positioning with smartphones.
The importance of Iberia for the restoration of the Mesozoic Alpine Tethys
Authors: Frasca Gianluca , Manatschal Gianreto , Cadenas Patricia , Mirò Jordi , Lescoutre Rodolphe
Published: March 2021

Fossil remnants of rifted margins sampled in orogens enable to unravel the nature of rocks, structures and conditions controlling the formation of rifted margins and lithosphere breakup. However, a major problem in orogens is that disconnected remnants of only one margin are preserved, while the conjugate has often been subducted and/or obliterated during convergence. Thus, our understanding of rift processes leading to lithosphere breakup is hampered by the impossibility to direct access to well-preserved examples of conjugate rifted margins fossilised onshore. Here we focus our attention on the Mesozoic Alpine Tethys, bounded by the European and African plates and interleaving crustal blocks such Iberia and Adria. Two key points have to be resolved in order to reconstruct conjugate distal margins in the Alpine Tethys paleogeographic setting. First, a restoration of the European western side of the Alpine Tethys has to be performed. Second, the position of Iberia during the Mesozoic has to be restored taking into account the evolution and opening of the southern North Atlantic and the Bay of Biscay. Here we propose a new Mesozoic kinematic model for Iberia, which is compatible at a first order and large scale with recently published data and interpretations from the North Iberian margin and the Pyrenean domain. We discuss the impact of the results for the reconstruction of the Alpine Tethys.
Historical evidence warns about disastrous tele-tsunami risk on the coast of East Africa.
Authors: Maselli Vittorio , Oppo Davide , Moore Andrew , Gusman Aditya , Mtelela Cassy , Iacopini David , Mshiu Elisante , Mjema Elinaza , Taviani Marco , Ortiz Joseph
Published: March 2021

The 2004 tsunami killed more than 200,000 people in Asia, but fewer than 300 in all East Africa. As a result, the search for ancient precursors has focused primarily along the coastlines of the Northern and Eastern Indian Ocean. No efforts to study past events were made in East Africa, leading to an underestimation of the tsunami risk in the region. Here we document a 1,000-yr old event that devastated a coastal Swahili settlement in Tanzania. Our study suggests a tsunami wave as the most likely explanation, in agreement with coeval tsunami deposits elsewhere across the Indian Ocean.  Numerical simulations of tsunami flooding suggest a megathrust earthquake from the Andaman-Sumatra subduction zone as a potential source, with a larger magnitude than the 2004 event. Our findings indicate that tele-tsunamis represent a serious threat to coastal societies along the Western Indian Ocean, with implications for future tsunami hazard and risk assessments.
V-FOR-WaTer: A Virtual Research Environment for Environmental Research
Authors: Strobl Marcus , Azmi Elnaz , Hassler Sibylle K. , Mälicke Mirko , Meyer Jörg , Zehe Erwin
Published: March 2021

The virtual research environment V-FOR-WaTer aims at simplifying data access for environmental sciences, fostering data publications and facilitating data analyses. By giving scientists from universities, research facilities and state offices easy access to data, appropriate pre-processing and analysis tools and workflows, we want to accelerate scientific work and facilitate the reproducibility of analyses.

The prototype of the virtual research environment consists of a database with a detailed metadata scheme that is adapted to water and terrestrial environmental data. Present datasets in the web portal originate from university projects and state offices. We are also finalising the connection of V-FOR-WaTer to GFZ Data Services, an established repository for geoscientific data. This will ease publication of data from the portal and in turn give access to datasets stored in this repository. Key to being compatible with GFZ Data Services and other systems is the compliance of the metadata scheme with international standards (INSPIRE, ISO19115).

The web portal is designed to facilitate typical workflows in environmental sciences. Map operations and filter options ensure easy selection of the data, while the workspace area provides tools for data pre-processing, scaling, and common hydrological applications. The toolbox also contains more specific tools, e.g. for geostatistics and soon for evapotranspiration. It is easily extendable and will ultimately also include user-developed tools, reflecting the current research topics and methodologies in the hydrology community. Tools are accessed through Web Processing Services (WPS) and can be joined, saved and shared as workflows, enabling more complex analyses and ensuring reproducibility of the results.
Ordination analyses in sedimentology, geochemistry and paleoenvironment - current trends and recommendations 
Authors: Bialik Or Mordechay , Jarochowska Emilia , Grossowicz Michal
Published: March 2021

Ordination is a family of multivariate exploratory data analysis methods. With the advent of high-throughput data acquisition protocols, community databases, and multiproxy studies, the use of ordination in Earth sciences has snowballed. As data management and analytical tools expand, this growing body of knowledge opens new possibilities of meta-analyses and data-mining across studies. This requires the analyses to be chosen adequately to the character of Earth science data, including pre-treatment consistent with the precision and accuracy of the variables, as well as appropriate documentation. To investigate the current situation in Earth sciences, we surveyed 174 ordination analyses in 163 publications in the fields of geochemistry, sedimentology and palaeoenvironmental reconstruction and monitoring. We focussed on studies using Principal Component Analysis (PCA), Non-Metric Multidimensional Scaling (NMDS) and Detrended Correspondence Analysis (DCA).

PCA was the most ubiquitous type of analysis (84%), with the other two accounting for ca. 12% each. Of 128 uses of PCA, only 5 included a test for normality, and most of these cases were not applied or documented correctly. Common problems include: (1) not providing information on the dimensions of the analysed matrix (16% cases); (2) using a larger number of variables than observations (24 cases); (3) not documenting the distance metric used in NMDS (55% cases); and (4) lack of information on the software used (38% cases). The majority (53%) of surveyed studies did not provide the data used for analysis at all and a further 35% provided data sets in a format that does not allow immediate, error-free reuse, e.g. as data table directly in the article text or in PDF appendix. The “golden standard” of placing a curated data set in an open access repository was followed only by 6 (3%) of the analyses. Among analyses which reported using code-based statistical environments such as R Software, SAS or SPSS, none provided the code that would allow reproducing the analyses.

Geochemical and Earth science data sets require expert knowledge which should support analytical decisions and interpretations. Data analysis skills attract students to Earth sciences study programmes and offer a viable research alternative when field- or lab-based work is limited. However, many study curricula and publishing process have not yet endorsed this methodological progress, leading to situations where mentors, reviewers and editors cannot offer quality assurance for the use of ordination methods. We provide a review of solutions and annotated R Software code for PCA, NMDA and DCA of geochemical data sets in the freeware R Software environment, encouraging the community to reuse and further develop a reproducible ordination workflow.
Englacial stratigraphy in Ellsworth Subglacial Highlands, West Antarctica
Authors: Napoleoni Felipe , Ross Neil , Bentley Michael J. , Jamieson Stewart S.R. , Smith Andrew M. , Uribe José-Andrés , Zamora Rodrigo , Brisbourne Alex M.
Published: March 2021

Airborne ice-penetrating radar surveys around the Ellsworth Subglacial Highlands (ESH) have mapped and dated englacial ice sheet layers, hereafter referred to as ‘Internal Reflection Horizons’ (IRHs). The geometry and internal structure of IRHs can reveal the cumulative effects of surface mass balance, strain, basal melt and ice dynamics, to improve understanding of the glacial history of West Antarctic Ice Sheet (WAIS). Despite the airborne-surveyed IRHs however, international efforts to develop a continental-wide scale coverage of IRHs (i.e. AntArchitecture), are limited by a lack of data in the critical regions between the upper reach of Pine Island Glacier (PIG), Rutford Ice Stream (RIS) and Institute Ice Stream (IIS). This region is important because any significant collapse of WAIS or reorganisation of ice flow would likely be felt in the ESH because it hosts deep subglacial troughs (Ellsworth Trough and CECs Trough), that represent a potential connection between the Weddell and Amundsen Seas. Using an extensive ground-based ice radar dataset acquired by Centro de Estudios Científicos (CECs) we bridge this regional gap by mapping IRHs across the Amundsen-Weddell divide of the WAIS. This work links airborne-derived IRH datasets across PIG and IIS, to develop an extensive layer characterisation across a large area of West Antarctica. We present the regional internal structure of the ice sheet, gridded paleo ice surfaces, and identify areas with complex IRH structures, and evaluate the possible glaciological processes responsible. We then compare our results with modelled outputs of ice sheet geometry and outline our current understanding of the past ice flow behaviour of the ESH, and the implications for WAIS glacial history. We consider our results in the context of the characterisation of ‘old-ice’ in WAIS and in relation to the upcoming plans for accessing subglacial Lake CECs in order to determine its history.
Intraseasonal Hydroclimate Variability in the Yucatán Peninsula During the Maya Terminal Classic Period: A Proxy Record of Palaeo-MJO?
Authors: Frappier Amy , Frappier Brian , Medina-Elizalde Martín , Lases-Hernández Maria Fernanda
Published: March 2021

Waves in the tropical atmosphere modulate rainfall and water vapor at the intraseasonal scale, including equatorial Rossby waves, Kelvin waves, and tropical disturbances organized by the planetary scale Madden-Julien Oscillation (MJO). The MJO’s regions of enhanced and suppressed convection travel slowly eastward, resulting in a characteristic 30-60 day rainfall cycle at tropical sites. The MJO’s pace and intensity vary over time and by location, influencing monsoons, El Niño-Southern Oscillation (ENSO) events, and tropical cyclone genesis/intensification. MJO-induced teleconnections influence extratropical weather anomalies, i.e. as atmospheric rivers. Despite forecast challenges, modeling studies indicate MJO sensitivity to anthropogenic climate forcing.

Records of pre-instrumental MJO behavior would advance efforts to assess tropical palaeoclimate and hydroclimate sensitivity to climate forcing factors. Palaeoclimate records of MJO intraseasonal variability have not been captured due to the scale of MJO relative to proxy resolution. Promising weekly dripwater monitoring results from Rio Secreto cave, Quintana Roo, Mexico, however, show the influence of sub-seasonal weather events on speleothem stable isotope proxy records.  We report a possible late Holocene palaeo-MJO signal in a ~weekly stalagmite oxygen isotope (δ18O value) record from Cueva Tzabnah, Yucatán, Mexico.

We re-sampled a well-studied stalagmite, Chaac, across the Maya Terminal Classic Period (c. 800-950 C.E.) and instrumental era. With continuous micromilling at 6.5 μm spacing and stable isotope analysis (CM-2 micromill and small-vial Kiel IV+MAT253), we reached ~50 samples/year. The re-sampled Chaac record reveals expected interannual-decadal hydroclimate signals and better resolves short-term variability. A recurrent pattern of δ18O value oscillations over about 4-12 samples (representing approx. 1-3 months). The amplitude of these intraseasonal-scale oscillations is around 0.3 - 0.5‰, smaller than annual/interannual variations. The intraseasonal pattern varies in amplitude, clarity, and frequency over time, similar to the modern MJO.

Intraseasonal stable isotopic oscillations in Chaac during the modern and Maya Terminal Classic Period most likely reflect local intraseasonal hydroclimate variability. Because this scale of rainfall variations is driven primarily by the MJO, we are investigating this pattern as a possible palaeo-MJO record. We will present the new Chaac record and results of wavelet analysis, and discuss prospects for intraseasonal tropical paleoclimate dynamics.
Geomorphological context of Quaternary desert loess - from dust sink to dust source
Authors: Crouvi Onn , Amit Rivka , Enzel Yehouda
Published: March 2021

Quaternary loess covers desert margins and vast areas of the Negev, southern Israel. The Negev loess is among the best-studied desert loess, with research going back to the early 20th century. The contrast between carbonate rocks of the Negev and its silicate-rich coarse-silt loess allows determining the loess sources, learning the synoptic-scale paleoclimatology, and exploring processes of coarse silt formation. Here, we present an overview of new perspectives on the origins and climatic significance of the Negev loess, expand on how (a) coarse silts affected soils farther downwind, and (b) how the loess has now turned into an active dust source.

The sources of the Negev loess are the (a) distal Sahara and Arabia delivering fine silts and clays, transported over thousands of kilometers, and (b) proximal sand dunes in Sinai and Negev, advancing and concurrently supplying the coarse silts to the loess accretion through eolian abrasion of sand grains. It was found that the coarse silts which compose the majority of the loess, commenced during the late middle Pleistocene – early late Pleistocene, coeval with the appearance of the advancing Sinai/Negev sand dunes and the first coarse silt accretion in regional soils; The main loess formation episode is ~95-10 ka, when the dunes appeared in the Negev. Within the loess, the dust mass accumulations rates (MAR), and consequently, soil formation rates, spatiotemporally vary according to specific site location and distance relative to the proximal sources. With increasing distance beyond the loess zone, both dust MARs and grain size gradually decrease; thus, whereas Mediterranean mountains located in central Israel, tens of kilometers downwind the loess, exhibit thick soils on top of the carbonate bedrock, the even wetter regions in northern Israel, located hundreds kilometers away from the loess, exhibit only thin soils. Thus, in Mediterranean regions located at the desert fringe, coarse silt influx is one of the main factors in determining the environmental sustainability, rather than only the precipitation amount.

During the Holocene, dust MARs in the Negev were much lower than late Pleistocene ones, and loess was not formed. Recently, the Negev loess became a prime source of dust mainly due to anthropogenic interferences, contributing to the regional dust cycle, and thus, at present the loess zone is a dust source rather than a dust sink. Today, the Negev loess is a non-replenishable natural resource that is slowly eroding and disappearing from the landscape.
Monitoring multiscale drought using remote sensing in a Mediterranean arid region.
Authors: Abdessamad Hadri , Mohamed El Mehdi Saidi , Abdelghani Boudhar
Published: March 2021

During the last few decades, the frequency of drought has significantly increased in Morocco especially for arid and semi-arid regions, leading to a rising of several environmental and economic issues. In this work, we analyse the spatial and temporal relationship between vegetation activity and drought severity at different moments of the year, across an arid area in the western Haouz plain in Morocco. Our approach is based on the use of a set of more than thirty satellite Landsat images data acquired for the period from 2008 to 2017, combined with the Standardized Precipitation Index (SPI) at different time scales and Standardized water-level Index (SWI). The Mann-Kendall and Sen’s slopes methods were used to estimate SPI trends and the Pearson correlation between NDVI and SPI were calculated to assess the sensitivity of vegetation types to drought. Results demonstrated that SPI experienced an overall upward trend in the Chichaoua-Mejjate region, except for 3-months time scale SPI in summer. The vegetation activity is largely controlled by the drought with clear differences between seasons and timesclaes at which drought is assessed. Positives correlations between the NDVI and SPI are dominant across the entire study area except in June when almost half of correlations is negative. More than 80% of the study domain exhibit a correlation exceeding 0.4 for SPI3 and SPI6 in March. Importantly, this study stresses that the irrigation status of land can introduce some uncertainties on the remote sensing drought monitoring. A weak correlation between the SPI and the SWI was observed at different time-scale. The fluctuations of the piezometric levels are strongly affected by the anthropogenic overexploitation of aquifers and proliferation of irrigated plots.
Mongolian dryland paleoenvironment and paleoclimate issues : calibrations and applicability of GDGT and pollen reconstructions over the Late Holocene.
Authors: Dugerdil Lucas , Joannin Sébastien , Peyron Odile , Jouffroy-Bapicot Isabelle , Vannière Boris , Bazartseren Boldgiv , Unkelbach Julia , Behling Hermann , Ménot Guillemette
Published: March 2021

Our understanding of climate changes throughout the Holocene is hampered by representativeness in sedimentary archives. Potential production and preservation biases of the markers are identified by comparing these proxies with modern environments. It is important to conduct robust calibrations on each biome. These calibrations use large database dominated by forest samples. The Mongolian plateau is especially characterized by low annual precipitation and continental annual air temperature. The characterization of the climate system of this area is crucial for the understanding of Holocene Monsoon Oscillations. This study focuses on the calibration of proxy-climate relationships for pollen and glycerol dialkyl glycerol tetraethers (GDGTs) by comparing large published Eurasian calibrations with a set of 49 new surface samples (moss polster, soil and mud from temporary dry pond). These calibrations are then cross-validated by an independent dataset of top-core samples and applied to two Late Holocene paleosequences in the Altai mountains and the Qaidam basin. We show that: (1) preserved pollen assemblages are clearly imprinted on the extremities of the ecosystem range but mitigated and unclear on the ecotones; (2) for both proxies, inferred relationships depend on the geographical range covered by the calibration database as well as on the nature of samples; (3) even if local calibrations suffer from reduced amplitude of climatic parameter due to local homogeneity, they better reflect actual climate than the global ones by reducing the limits for saturation impact, (4) a bias in climatic reconstructions is induced by the over-parameterization of the models and (5) paleoclimate values reconstructed here are consistent with Mongolia-China Late Holocene climate trends, and validate the application of local calibrations for both pollen and GDGTs. We encourage the application of this surface calibration method to reconstruct paleoclimate and especially consolidate our understanding of the Holocene climate and environment variations in Arid Central Asia.
Nile floods during the last African Humid Period: a seasonal record from the deep-sea fan
Authors: Blanchet Cecile , Ramisch Arne , Tjallingii Rik , Brauer Achim
Published: March 2021

Seasonal floods are life-supporting events in the Nile Valley and have been crucial to the development of complex societies. Present populations depend on their occurrence but the alteration of fluvial dynamics under climate change remains elusive. In order to better understand how fluvial dynamics respond to climatic changes, we explore past flood dynamics of the Nile River using a unique finely laminated sequence from the Nile deep-sea fan.

Today, floods occur during the summer, when monsoonal rainfall hits the Ethiopian highlands and feeds the Blue Nile. Core P362/2-33 covers the past 9.5 ka BP and is ideally located to record changes in fluvial dynamics during periods of stronger monsoon activity such as the Saharan Humid Periods. The absence of oxygen in the Mediterranean bottom waters during the last Saharan Humid Period (during sapropel S1 deposition) allowed to preserve the laminated structure between 9.5 and 7.5 ka BP.

We focus here on examining the nature of the laminations in order to 1) understand the deposition mechanism and 2) obtain a reconstruction of past fluvial dynamics at seasonal resolution.

Microfacies analysis and elemental micro-XRF scanning indicate that couplets of alternating dark- and light-coloured layers represent seasonal deposits of Nile discharge and marine hemipelagic sedimentation, respectively. Preliminary lamination counts suggest that couplets were deposited at an annual rate for most of the record. Increases in layer thickness is observed around 9.5 and 9.1 ka BP, followed by a gradual decrease until 8 ka. Careful examination of lamination structure and time-series analysis of layer counts will permit to further explore sub-annual changes in flood dynamics during the Saharan Humid Period. Finally, due to its high temporal resolution, our record has the potential to link reconstructions of Nile discharge to other regional archives of hydrological changes (e.g., speleothems, lakes) and thereby identify overarching forcing mechanisms.
Detection of soil pipe network by electromagnetic induction (EMI) in relation to the high resolution UAV data
Authors: Bernatek-Jakiel Anita , Kondracka Marta , Liro Maciej
Published: March 2021

Subsurface erosion by soil piping is a widespread land degradation process that occurs in different soil types around the world. Recent studies have shown that piping erosion may lead to the significant soil loss and disturbances of ground surface. This process accelerates also gully erosion. However, it is still omitted in hydrological models of a catchment, as well as in soil and water erosion models. It seems that the main problem in soil piping studies lies on the basic issue, i.e., the detection of subsurface tunnels (soil pipes). As geophysical methods enable the exploration below the ground surface, they are promising in soil piping studies.

 

This study aims to evaluate the suitability of the electromagnetic induction (EMI) to detect subsurface network of soil pipes. The detailed study was conducted in the small catchment (Cisowiec) in the Bieszczady Mts. (the Eastern Carpathians, SE Poland), where pipes develop in Cambisols. The measurements were carried out using a conductivity meter EM38-MK2 (Geonics) in both vertical and horizontal measuring dipole orientations. The EM38-MK2 provided simultaneous measurements of apparent electrical conductivity with two transmitter receiver coil separation (0.5 m and 1 m). In order to compare subsurface data with the surface response (i.e., depressions and collapses), the high resolution DEM and orthophotos have been produced. These data have been prepared using Structure from Motion (SfM) technique based on the images taken from the low altitude by an Unmanned Aerial Vehicle (UAV; DJI Phantom-4 equipped with a 1' camera). The UAV-derived products (orthophotos and DEM) have the resolution of 0.014 x 0.014 m and point density of 9240 per 1 m2.

 

The EMI results are presented on the maps that gathered data at three depths (0.4 m, 0.75 m, 1.5 m). The results revealed the soil pipes as areas characterized by higher electrical conductivity than the surroundings. The spatial distribution of subsurface tunnels corresponds with the ground depressions and collapses detected in the field and seen on the high resolution DEM and orthophoto. The use of EMI in piping research has been evaluated.

 

The study is supported by the National Science Centre, Poland within the first author’s project SONATINA 1 (2017/24/C/ST10/00114).
Shock-induced radiation belt dynamics: Coordinated observations of drift echoes and ULF modulations in the dayside magnetosphere 
Authors: Chen Xingran , Zong Qiugang , Liu Ying , Hao Yixin , Fu Suiyan , Ren Jie , Yue Chao
Published: March 2021

We employ conjunctive observations of particle fluxes and electromagnetic fields in the solar wind, magnetosheath, and dayside magnetosphere to investigate the radiation belt dynamics in response to the impingement of a fast forward interplanetary shock on 7 September 2017. Particularly, drift echoes associated with the one-kick acceleration caused by the shock-induced magnetosonic pulse and oscillations in the Pc 4 range associated with the azimuthally localized ULF waves are identified concurrently in the in-situ particle measurements obtained by the twin Van Allen Probes in the dayside outer radiation belt. Based on this observational evidence, we demonstrate that the radiation bet can be efficiently disturbed via the two mechanisms simultaneously by the shock arrival. We also depict the characteristic features to distinguish between the two mechanisms from an observational approach.
Skew-Kappa distribution functions & whistler-heat flux instability in the solar wind
Authors: Zenteno-Quinteros Bea , F. Viñas Adolfo , Moya Pablo S.
Published: March 2021

Electron velocity distributions in the solar wind are known to have field-aligned skewness, which has been observationally characterized by the presence of secondary populations such as the halo and strahl electron components. This non-thermal feature provides energy for the excitation of electromagnetic instabilities that may play a role in regulating the electron heat flux in the solar wind by wave-particle interactions. Among the wave modes excited in regulating the electron non-thermal features is the whistler-mode and its so-called whistler heat-flux instability (WHFI). In this work, we use kinetic linear theory to analyze the stability of the WHFI in a solar wind like plasma where the electrons are described as a single population modeled by a Kappa distribution to which an asymmetry term has been added. We solve the dispersion relation numerically for the parallel propagating whistler-mode and study its linear stability for different plasma parameters. We also show the marginal stability thresholds for this instability as a function of the electron beta and the parallel electron heat flux and present a threshold condition for instability that can be modeled to compare with observational data. The principal result is that the WHFI can develop in this system; however, the heat flux parameter is not a good predictor of how unstable this wave mode will be. This is because different plasma states, with different stability to WHFI, can have the same initial heat flux. Thus, systems with high <img title="This is the rendered form of the equation. You can not edit this directly. Right click will give you the option to save the image, and in most browsers you can drag the image onto your desktop or another program." src="https://latex.codecogs.com/gif.latex?q_%7B%5Cparallel%20e%7D/q_0"> can be stable enough to WHFI so that it cannot effectively modify the heat flux values through wave-particle interactions
Mechanisms and effects of dry and wet Sahel epochs
Authors: Bruun John T , Sheen Katy , Collins Mat
Published: March 2021

The Sahel is Northern African region between the equator and the Sahara desert. It is home to a belt of semi-arid grassland that stretches from the Atlantic and across the continent westward towards the Red Sea. The monsoon type rainfall season that occurs in this region is influenced by the way that moisture transport along this belt region combines along the Inter Tropical Convergence Zone (ITCZ). The Sahel is one of the most productive crop areas of Africa, and if the rains fail – it has long lasting implications for its community. Due to its  planetary location dry conditions pervade the Sahel for most of the year, with food production and livelihoods reliant on the summer monsoon rainy season between July and September. In this study we use (where available) up to 100 years of re-analysis records (GPCC rainfall, NCAR wind and HadiSST ocean data) together with an accurate signal decomposition approach (dominant frequency state analysis, DFSA). With this we assess how the teleconnection influence of the Pacific ENSO and the Atlantic dipole mechanisms influence the dry and wet Sahel rain conditions. The severe Sahelian drought of the 1980’s is shown to be a compounded sequence of drying dynamic effects that combined to occur suddenly over the span of 5-10 years. Our work indicates that dry and wet conditions appear to be related to land-air evaporation and condensation in the vicinity of the Sahel river catchments, with the land locked Lake Chad catchment having a particularly sensitive arid climate. Our latest finding’s help explain how the Atlantic and Pacific physical mechanism influence the Sahel monsoon and its extremes. With an assessment of agricultural data we also show how agricultural growth in the region is impacted by these factors. We present and discuss Africa dry and wet rainfall epoch forecasts over the next 30 years for Sahel based on stable and altered climate hysteresis scenarios.
The influence of fluctuating SST by satellite data in the Barents and Norwegian seas during periods of early ontogenesis NEA cod in 1998-2016 on its strength.
Authors: Vanyushin George , Bulatova Tatiana
Published: March 2021

The influence of fluctuating SST by satellite data in the Barents and Norwegian seas during periods of early ontogenesis NEA cod in 1998-2016 on its strength.

 

G.P. Vanyushin and T.V. Bulatova

 

Russian Federal Research Institute of Fisheries and Oceanography (VNIRO), Moscow, Russia

e-mail: ladimon@mail.ru

 

Abstract

The paper presents preliminary results of the analysis of the influence of fluctuating seasonal sea surface temperature in the Barents and Norwegian seas during early ontogenesis of the Northeast Atlantic (NEA) cod in the period 1998-2016 on its future strength of generations at age 3+ accordingly in 2001-2019. The temperature data for control zones of these seas (May-October) to 1998-2016 were obtained from the analysis of daily infrared information by the NOAA series of satellites and quasisynchronous temperature data "in situ" from ships, buoys and coastal stations. Data about the strength of NEA cod generations at age 3+ to 2001-2019 was taken from ICES reports. Real comparative analysis was conducted for following three-zones: 1 - Murman-Novaya Zemlya zone (69-76N 30-54E), 2 – North Cape zone (71-76N 17-30E), 3 – West-Spitsbergen zone (69-76N 11-17E). Direct comparative analysis of these indicators revealed very low relationship between them, so R(less) 0,1 for every zone and the whole period. That is why we tried to use the data about distribution of monthly solar activity during solar cycles 23-24 in considering years. The border between these solar cycles is 2008-2009. New comparative analysis of the same indicators separated by cycle 23 (1998-2008 solar activity) and by cycle 24 (2009-2016 solar activity) revealed rather opposite results. In first case (cycle 23) R was received for zone 1 +0,72, zone 2 +0,62 and for zone 3 +0,50, but for cycle 24 R was accordingly equal for zone 1 -0,60, zone 2 -0,66 zone 3 -0,38. So, the influence of seasonal temperature conditions in the Barents and Norwegian seas during 1998-2016 on the strength of new NEA cod generations at age 3+ to 2001-2019 changed its sign on border between 23 and 24 cycles of solar activity for considering years. Perhaps, obtained dependence between these indicators is fairly only for this period of time. For all that ought to note intensification of different character influence of solar activity these cycles towards east.

 

Keywords: satellite monitoring, sea surface temperature (SST), the North-East Atlantic (NEA) cod generations, solar activity, comparative analysis.
Flank motion detected between 2010 and 2014 through InSAR time-series analysis at Pacaya Volcano, Guatemala
Authors: Gonzalez Santana Judit , Wauthier Christelle
Published: March 2021

Volcanic flank collapse has caused over 20,000 casualties in the past 400 years, and is one of the most dangerous hazards affecting communities and infrastructure near volcanoes. Flank instability has mostly been investigated at ocean volcanoes, due to their ability to trigger deadly tsunamis, however, these collapses are prevalent across volcanic settings, with all but one volcano in Guatemala with elevation over 2000m having experienced flank collapse, like Pacaya Volcano. At Pacaya, there is evidence for at least one past collapse, and transient SW flank motion has been identified accompanying vigorous eruptions in 2010 and 2014. We use InSAR time-series analysis to reveal, for the first time, long-term displacement of the SW flank of Pacaya during a period of volcanic quiescence from 2011-2013. This motion extended into 2014, with increased displacement rate attributed to dike intrusion during a major eruption. Subsequent static stress change analyses investigated the interactions between the modeled dike intrusion and detachment slip. Our research highlights that long-term flank motion might be more prevalent than currently recognized and that an awareness of existing structural weaknesses such as detachment faults and of possible magma-faulting interactions is vital when assessing the likelihood and style of volcanic flank collapse.
A critical analysis of French flood risk governance
Authors: Kougkoulos Ioannis , Merad Myriam , Cook Simon , Andredakis Ioannis
Published: March 2021

France experiences catastrophic floods on a yearly basis, with significant societal impacts. In this paper, we critically evaluate the French Flood Risk Governance (FRG) system with the aim of identifying any shortcoming and, thereby, to suggest improvements. To do so, we employ a historical assessment of catastrophic past flood events in the Provence-Alpes-Côte d'Azur (PACA) region and perform Strengths-Weaknesses-Opportunities-Threats (SWOT)-analysis. Our evaluation shows that despite persistent government efforts, the impacts of flood events in the region do not appear to have lessened over time. Identical losses in the same locations (e.g. Riou de l’Argentière watershed) can be observed after repetitive catastrophic events (e.g. 2015, 2019) triggering local inhabitant protests. We argue that the French FRG system can benefit from the following improvements: a) regular updates of the risk prevention plans and tools; b) the adoption of a Build Back Better logic instead of promoting the reconstruction of damaged elements in the same locations; c) taking into account undeclared damages into flood risk models (and not only those declared to flood insurance); d) increased communication between the actors of the different steps of each cycle (prepare, control, organise etc.); e) increased communication between three main elements of the cycle (risk prevention, emergency management and disaster recovery); f) an approach that extends the risk analysis outside the borders of the drainage basin (to be used in combination with the current basin risk models); and g) increased participation in FRG from local population. We also briefly discuss the use operational research methods for the optimisation of the French FRG.
Using ground-based thermography to analyse surface temperature distribution and estimate debris thickness on Gran Zebrù glacier (Ortles-Cevedale, Italy)
Authors: Tarca Giulia , Guglielmin Mauro
Published: March 2021

In this study ground-based thermal infrared imaging was used to obtain surface temperatures distribution and to estimate the thickness of supraglacial debris on a mountain glacier. The study area is the eastern tongue of Gran Zebrù glacier (Ortles-Cevedale group, Central Italian Alps, Italy), having an area of about 0.23 km2. The glacier surface includes some areas completely covered by debris. 
We used a FLIR E85 Thermal Camera to take 17 thermal images of the glacier surface on 30 September 2019, the images were taken from a distance of about 100 m from the glacier front. The thermal images were combined into a single panoramic image and calibrated in order to obtain surface temperatures. In addition, we manually measured the debris thickness and took thermal images at 18 points on the glacier, in a sector with a continuous debris cover. From these data, an exponential equation correlating measured debris thickness and debris surface temperature was obtained and applied to the panoramic thermal image to estimate debris thickness at each pixel with surface temperature > 0 °C.
This method allowed us to obtain the distribution of surface temperatures and of debris thicknesses with a high spatial resolution, between 0.11 and 1.10 m. The obtained surface temperatures show a spatial variability, ranging between -10.7 and 26.4 °C, with a mean of 5.8 °C. Snow and ice have mean temperature of -1.2 °C, while the debris cover a mean temperature of 14.1 °C. The estimated debris thicknesses have an inhomogeneous distribution on the glacier, ranging between 0.03 and 0.51 m, with a calculated mean debris thickness of 0.14 m in the areas completely covered by debris, that is in good agreement with field data.
Operationalizing Human Agency in World-Earth System Models
Authors: Otto Ilona M.
Published: March 2021

The role of humans significantly altering natural systems is undisputed and human influence has been the dominant cause of global warming since the mid-20th century. If components of the Earth System are pushed beyond critical states, further large-scale impacts on human and ecological systems are likely. However, In the Anthropocene, humans are also seen as a force able to facilitate a global sustainability transformation. In other words, the individual becomes a focal point and, applying its inherent human agency, understood as the ability to shape life circumstances, opens up an analytical level incorporating choices and future action plans. The paper systematically reviews approaches that are relevant for operationalizing human agency in global human-environmental interaction models. The key aspects include representing inequalities in the resource and energy that are used to support lifestyles of different social groups, developing a hierarchical networked representation of social structure layers and rules for agent operation at the different levels, and finally building feedback and learning mechanisms that are used by agents to respond to changing environmental conditions and the behaviour of other agents.
Delayed soil-moisture and hydrological drought impacts in mountain regions
Authors: Stephan Ruth , Erfurt Mathilde , Stahl Kerstin
Published: March 2021

Droughts are among the most damaging natural hazards leading to a wide range of impacts also in the water-rich mountain regions. In recent years, drought conditions and impacts have been reported frequently in the European Alpine region, possibly because climate change affects mountain environments more rapidly than others. However, in mountain regions the propagation of drought signals through the hydrological cycle and into different environmental and societal impact occurrence are poorly understood, especially regarding the impacts’ seasonal patterns and delayed effects. This study aims to improve the understanding of the droughts’ characteristics and their impacts from the high elevation headwater regions down to plateau and foothill areas. Specific climate conditions in high elevation regions determine an alpine environment, economy and society that differs from the pre-Alpine regions. Subsequently, impacts are expected to vary as well and indices for drought monitoring may have to be selected specifically for such a region. The European Drought Impact Report Inventory (EDII) compiles text-reports on negative drought impacts across Europe and classifies them into 15 categories with 108 subtypes. An updated version focusing on the ‘Alpine Space’ released as EDIIALPS V1.0 contains more than 3,200 reports about drought impacts. The most relevant categories are Agriculture and livestock farming and Public water supply. This data allowed an analysis of the seasonal patterns of drought impacts in several categories for four sub-regions in the Alpine Space: pre-Alpine vs. high-elevated region, Northern vs. Southern region. Assigning the impacts subtypes to drought type, soil-moisture drought (SMD impacts) and hydrological drought (HD impacts) allowed the derivation of smoothed seasonal “impact regimes”. The peak of HD impacts occurred later in the year than the SMD impact peak, most clearly in the high-elevation region, with the latest increase of HD impacts in May and strongest decrease between November-December. This pattern is less clear for the Southern region. SMD indices and HD indices that may be used for monitoring and early warning need to be targeted to and tested for capturing these delays.
Montreal Protocol to delay ice-free Arctic by a decade
Authors: England Mark , Polvani Lorenzo
Published: March 2021

Recent work has shown that a rapid rise in the emission of ozone depleting substances resulted in substantial Arctic warming and accelerated Arctic sea ice loss over the second half of the twentieth century. However, ozone depleting substances have been heavily regulated since the Montreal Protocol entered into effect in 1989, and their atmospheric concentrations have been stabilized and are now decreasing. This raises the obvious and important questions of the impact of the Montreal Protocol on climate change in the Arctic.

More specifically we are here interested in quantifying the impact of the Montreal Protocol on the date of the first ice-free Arctic summer (defined as the first occurrence of Arctic sea ice extent below 1 million km2). The timing of the ice-free Arctic is of great interest both to stakeholders in the Arctic and to the scientific community.

To address this question, we have performed and analyzed ten-member ‘World Avoided’ companion ensembles to the CESM Large Ensemble (using RCP8.5 forcings) and to the CESM Medium Ensemble (using RCP4.5 forcings). The companion ensembles are identical to their CESM-LE and CESM-ME counterparts, respectively, except for the levels of ozone depleting substances which do not decrease following the Montreal Protocol, but instead increase at a rate of 3.5% a year. This allows us to isolate the effect of the Montreal Protocol on Arctic sea ice trends by simulating what would have happened if it had never been enacted (hence the name, ‘World Avoided’). We examine both RCP8.5 and RCP4.5 forcings, to quantify the uncertainty related to emissions scenarios over the coming decades.

We find that without the Montreal Protocol the mean date of the first ice-free Arctic advances from 2041 to 2033 for the RCP8.5 forcings, and from 2050 to 2035 for the RCP4.5 forcings. Thus, enacting the Montreal Protocol has delayed the onset of an ice-free Arctic by approximately one decade. This signal is robust when accounting for the high levels of internal variability in Arctic sea ice trends. Our results are also robust to different definitions of ‘ice-free Arctic’. Overall our results highlight the importance of the Montreal Protocol as a major climate mitigation treaty, even for the Arctic, where no ozone-hole has formed.
Characteristics of the 30 October 2020 Mw 7.0 Aegean Sea earthquake from sea level data analysis and numerical modeling
Authors: Heidarzadeh Mohammad , Pranantyo Ignatius Ryan , Okuwaki Ryo , Dogan Gozde Guney , Yalciner Ahmet Cevdet
Published: March 2021

The 30 October 2020 tsunami in the Aegean Sea was generated by an Mw 7.0 normal-faulting earthquake at a depth of 21 km. The earthquake epicenter was near the city of Izmir (Turkey) in the Aegean Sea and left 117 fatalities in Turkey and two deaths in Greece. A moderate tsunami was generated, which attacked the nearby coast of Turkey and the north coast of Samos island, Greece.  A maximum runup height of ~3.8 m was observed in Akarca with extensive inundation at the low elevation nearshore areas of the small bays from Akarca (South) to Alacati (North) of the central Aegean coast of Turkey (field surveys by Yalciner et al., 2020). The maximum tsunami penetration was ~2500 m along Azmak streambed at Alacati, Turkey. One casualty and at least one injury were directly attributed to the tsunami in Sigacik, Turkey. The predecessors of this event were other normal-faulting events: i) Lesvos-Karaburun (Mw 6.3) earthquake (Greece-Turkey) on 12 June 2017 approximately 110 km to the North-northwest, and ii) Bodrum-Kos (Mw 6.6) earthquake (Turkey-Greece) on 20 July 2017 approximately 110 km to the south-southeast of the epicenter of the 30 October 2020 event. The events of 2017 and 2020 show high similarities in terms of faulting mechanism and tsunami-genesis. The tsunami generated by the last event caused extensive loss of properties and damage to marine vessels. Here, we study the 30 October 2020 tsunami through analysis of eight tide gauge records as well as numerical simulations. Tide gauge data revealed that the tsunami’s zero-to-crest amplitudes, on tide gauges, was in the range of 5 – 12 cm with maximum amplitude (12 cm) recorded at Kos (Greece). The tsunami duration was unusually long and varied from 20 h to 35 h. Such long tsunami oscillations are not expected from an Mw 7.0 normal-faulting tsunamigenic earthquake and can be most likely attributed to several reflections due to the confined nature of the Aegean Sea region. We conducted Fourier and Wavelet analyses to detect tsunami’s spectral characteristics. Our tsunami simulation was able to reproduce most features of the recorded waves both in terms of amplitudes and duration. This research is suported by Royal Society (UK), grant number CHL/R1/180173. 