bluuebunny/crossref_metadata_2025 huggingface dataset:
Timing and magnitude of vertical-axis rotations in the eastwards-flanking synorogenic sediments of the South-Pyrenean fold-and-thrust belt. Kinematics and origin of the salient curvature.
Authors: Peigney Charlotte , Beamud Elisabet , Gratacós Óscar , Valero Luis , Soto Ruth , Roca Eduard , Muñoz Josep Anton
Published: March 2020

The South-Pyrenean fold-and-thrust belt consists of three major thin-skinned thrust sheets (Bóixols, Montsec and Serres Marginals) made up of uppermost Triassic to Oligocene cover rocks emplaced during Late Cretaceous-Oligocene times. In its central part, it forms a major salient (the Pyrenean South-Central Unit) whose geometry is controlled by the areal distribution of the pre-orogenic Upper Triassic and synorogenic Eocene salt décollement layers. Both westwards and eastwards, the salient is fringed by Paleogene synorogenic deposits that are deformed by detachment folds with orientations ranging from N-S to E-W. In the western edge of the salient, the varying trend of the folds is a result of synorogenic vertical axis rotations (VAR) which caused the clockwise rotation of the folds from an initial predominant E-W trend to the current NW-SE to NNW-SSE trend. The salient, at least on its western part, developed from a progressive curve originated from divergent thrust transport directions and distributed shortening.

The aim of our study is to get a better understanding of the whole salient, by studying the kinematics of the deformation on the most frontal part of its eastern edge. Here, some sparse anticlockwise rotations have been reported but their origin and their possible relationship with the distribution of the salt décollements has not yet been addressed. For this purpose, 78 paleomagnetic sites have been sampled on the synorogenic upper Eocene-Oligocene materials of the NE Ebro foreland Basin, in the Artesa de Segre area, focusing on the limbs of oblique salt-cored anticlines (Ponts, Vilanova de l’Aguda, Cardona) which are detached above the synorogenic Eocene-Oligocene evaporites of the Cardona and the Barbastro formations. VAR analyses principally show anticlockwise rotations similar to those previously identified to the North in the Oliana Anticline, although a small number of clockwise rotations were also detected.

In addition to the VAR analysis, a magnetostratigraphic study of the Eocene-Oligocene continental materials of the northern limb of the Sanaüja Anticline has been conducted in order to constrain the age of these rotations from stratigraphic correlations. The demagnetization of 104 samples from a ca. 1100 m thick magnetostratigraphic section shows Priabonian to Rupelian ages for this succession. The integration of our results on timing, direction and magnitude of foreland VAR with previous paleomagnetic and structural data from both the western and eastern boundaries of the frontal thrust of the Pyrenean South-Central Unit will allow the understanding of the kinematics of the thrust salient as a whole.
Seismogenic behaviour in the Lesser Antilles: Insights from geodetic observations
Authors: van Rijsingen Elenora , Calais Eric , Jolivet Romain , de Chabalier Jean-Bernard , Jara Jorge , Symithe Steeve , Robertson Richard , Ryan Graham
Published: March 2020

The Lesser Antilles subduction zone is a challenging region when it comes to unravelling its seismogenic behaviour. Over the last century, it has been seismically quiet, with no large thrust events recorded, leading to the question whether this subduction zone is able to produce large interplate earthquakes or not. The slow subduction velocity of ~20 mm/yr complicates this even further, as mega-earthquake recurrence times would be up to many hundreds of years in the case of a fully locked subduction interface, and up to several thousands of years for a partially locked interface. The record of two large historical earthquakes, a M ~8 in 1839 and M ~8.5 in 1843, is often referred to as evidence supporting the seismic character of the Lesser Antilles subduction zone. It remains, however, questionable whether these events actually occurred along the subduction interface.

Here we use GPS data acquired on various islands within the Antilles to infer interseismic coupling along the Lesser Antilles Arc. Previous block models have suggested low coupling of the subduction interface, making the occurrence of large megathrust earthquakes less likely. However, the non-uniqueness of these inversions, as well as uncertainties related to the distance between GPS stations and the subduction trench, cast doubts on how well the inferred coupling represents the actual degree of locking along the subduction interface. In this study, we attempt to improve these estimates, by using a Bayesian approach to derive a meaningful set of uncertainties on the distribution of interseismic coupling. By exploring the entire range of model parameters, we are able to provide a probabilistic estimate of interseismic coupling. To further improve our analysis with respect to previous models, we incorporate a layered elastic structure, as well as a more realistic fault geometry, testing two different slab models.

Our results suggest that the subduction interface of the Lesser Antilles subduction zone is most likely to be uncoupled. A sensitivity analysis highlights the deeper part of the interface (i.e., 30-60 km depth) as the region with higher sensitivity, since the GPS stations are distributed mostly above that portion of the subduction. A test regarding the proposed 1843 rupture contour reveals that this area is very unlikely to be locked. This apparent aseismic character of the Lesser Antilles raises questions about the role of slow slip along the interface. We therefore also analyse GPS time series to assess the spatial and temporal distribution of transient deformation signals in the region.
Intense dB/dt variations driven by near-Earth Bursty Bulk Flows (BBFs): A case study
Authors: Wei Dong , Dunlop Malcolm , Yang Junying , Yu Yiqun , Wang Tieyan
Published: March 2020

During geomagnetically disturbed times, geomagnetically induced currents (GICs) flow in power systems potentially causing damage to the system. The largest GICs are often produced when the surface geomagnetic field abruptly changes (for example, an induced rate of change of the horizontal magnetic field component, dH/dt). It is well established that intense dB/dt variations take place in the main phase of a geomagnetic storm, particularly while magnetic substorms occur during the active period. However, there are currently few studies that report intense dB/dt variations which are directly driven by bursty bulk flows (BBFs) at geosynchronous orbit. In this study, we investigate the characteristics and response in the magnetosphere-ionosphere system during the recovery phase of a geomagnetic storm that occurred on 7 January 2015 by using a multi-point approach combining space-borne Cluster and SWARM measurements, and a group of ground-based magnetometer observations. The locations of Cluster and SWARM map to the same conjugate region as the magnetometer ground stations at the time of the BBF. The measurements show that corresponding signals in all measurements occur simultaneously in this region. Our results suggest that the most intense dB/dt (dH/dt) variations are associated with R1-type FACs that are driven by BBFs at geosynchronous orbit around substorm onset.
The Use of LiDAR DTM in Landslide Susceptibility/Hazard Analysis
Authors: Lee Chyi-Tyi , Ji Tsung-Chi
Published: March 2020

High-resolution DTM does not always help build a good landslide prediction model. When we are using LiDAR DTM in producing a topographic-related factor for grid-based landslide susceptibility/hazard analysis, the selection of an optimal measurement scale becomes important. Because the resolution of LiDAR DTM may be up to 1 meter, and the average landslide size may be more than 1 thousand square meters, to use a conventional 3x3 kernel for calculation of a factor value is not valid. Actual tests tell us, to use a 15x15 and larger kernel for calculation may yield a more effective factor for interpreting the landslide distribution in a study area.

A test area was selected at the catchment of the Zengwen Reservoir in southwestern Taiwan. The original 1mx1m LiDAR DTM was firstly reduced to a 2mx2m DTM for analysis. Factors of slope gradient, slope aspect, topographic roughness, slope roughness, plan curvature, profile curvature, tangential curvature and total curvature are analyzed by using a series of kernels in different sizes up to 25x25 for comparison. And success rate curve method was used to evaluate the effectiveness of each factor in interpreting landslide distribution. Highest AUC is selected as the most effective one and the kernel size which yield that is the optimal measurement scale of the factor.

A 3x3 kernel has a measurement scale of 2h and is 4 meters (h is grid size of 2 meters), a 25x25 kernel has a measurement scale of 24h and is 48 meters. Factors calculated from an optimal measurement scale will be selected for construction of a landslide susceptibility model. The success rate and prediction rate of this model would be significantly increasing as compared with the model built from conventional 3x3 kernel calculated factors. Finally this optimal susceptibility model was used to construct a landslide hazard model for prediction of landslide distribution under different triggering events.
Coastal groundwater stable isotope composition as predictor and measure of marine pollution
Authors: Mance Diana , Mance Davor , Vukić Lušić Darija
Published: March 2020

There are numerous health hazards arising from recreational exposures to microbiologically polluted marine environments. Microbial contaminants from catchment areas of coastal and submarine springs (due to leakages of private septic tanks and/or faults in sewage systems) could be a cause of microbial marine quality worsening after heavy rainfalls. Before testing this hypothesis groundwater dynamics should be known. Stable isotopes of water have been proven to be a very useful tool in karst hydrology and we used them as a mediator variable in predicting marine coastal water microbial contamination. 
We refer to the problem of the pollution from the position of environmental economics and economic institutional mechanism design, where such ecological problems are described as either stock or flow problems. Stock pollution is strongly dependent on the concentration potentials of the pollutant in the medium. Flow pollution depends on the speed of emission of the pollutant in the medium, as well as on the rate of its depletion by natural causes. On the example of fecal indicator bacteria Escherichia coli and enterococci propagating through karstic underground and finally ending in seawater we show how stable isotope composition of coastal springs’ water can be used to differentiate marine pollution into stock or flow. 
We tested the approach on two close coastal locations located at the Kvarner Bay (the Northern part of the Croatian part of the Adriatic Sea). Locations differ in terms of the open and closed sea as well as anthropogenic pressure. Groundwater and marine samples were collected during two consecutive bathing seasons (mid-May – mid-September). The Panel Data Pairwise Granger Causality test was used to test for statistical associations. Static Estimated General Least Squares (EGLS) and dynamic Generalised Method of Moments (GMM) statistical methods were used to distinguish between stock and flow pollution. 

This work was partially supported by the University of Rijeka as part of the research projects uniri-pr-prirod-19-24 and uniri-biomed-18-292.
Control on millennial scale events (H-events) inferred from triple oxygen isotope ratios of speleothems from a Northeast Indian cave
Authors: Mahata Sasadhar , Duan Pengzhen , Sha Lijuan , Baker Jonathan , Kathayat Gayatri , Dong Xiyu , Zong Baoyun , Ning Youfeng , Zhang Haiwei , Cheng Hai
Published: March 2020

The carbonate 17O anomaly (Δ17O) has recently been developed as a geochemical proxy for estimating the relative humidity of moisture at the source point of evaporation, which can be a vital tool in paleoclimate research. Speleothem Δ17O variability in particular may provide a quantitative constraint on moisture regimes at millennial and orbital timescales—far longer than can be addressed by analyzing 17O in other materials, such as tree rings. Modern observations and calibration studies have established a robust negative correlation between the Δ17O (17O excess) of rainfall and relative humidity, so that Δ17O is enhanced during arid conditions at the moisture source. Herein, we report novel triple oxygen isotope data across the Last Glacial in speleothems collected from Cherrapunji Cave, northeastern India. Triple oxygen isotope measurements were obtained by an O2-CO2 Pt-catalyzed oxygen-isotope equilibration method. Preliminary results suggest lower Δ17O in speleothems during cold periods (e.g. Heinrich Events), which would imply higher relative humidity over the oceanic moisture source. Importantly, higher source relative humidity does not necessarily imply changes in precipitation amount at the cave site. While it is possible that a substantial geographic shift in the moisture source region (or additional contributions from secondary sources) could obfuscate the Δ17O signal, we argue that this explanation is unlikely for our study site. Alternatively, we cannot exclude the effects of excessive moisture recycling in the tropical ocean, which can enhance the 17O anomaly in cloud vapor (particularly if combined with large temperature swings) and thereby alter speleothem Δ17O. To refine our interpretation of the Δ17O signal in Cerrapunji Cave samples, we investigate multiple cold periods, as well as coeval samples from the Asian Summer Monsoon region. Finally, we compare our results with novel data from westernmost Asia, where temperature variations during cold events are more likely to be accompanied by large shifts in predominant moisture source, due to the migration of wintertime westerlies.
Superposition of nappe stacking and extensional exhumation in the Sierra de los Filabres (Southeast Spain)
Authors: Porkoláb Kristóf , Hupkes Jasper , Matenco Liviu , Willingshofer Ernst , Wijbrans Jan
Published: March 2020

The Sierra de los Filabres mountain range in the Betics system of SE Spain is one of the best natural laboratory to investigate processes associated with nappe stacking and subsequent exhumation of metamorphic rocks during the orogenic evolution. Existing research separates the Iberia-derived high-pressure, amphibolite facies Nevado-Fillabrides complex in a lower tectonic plate position from the lower grade ALCAPECA microcontinent-derived Alpujárride complex in an upper tectonic plate position. Their nappe-stack contact is also defined as an extensional detachment that controls the exhumation of the higher grade Nevado-Fillabrides complex. We have tested this model with a detailed (micro-)structural and lithological analysis complemented by 40Ar/39Ar white mica dating of key shear zones. We aim to define key shear zones that separate different tectonic units, to determine the kinematics and timing of main deformation phases, and to understand the interplay between burial and exhumation structures. The results show that shearing related to the subduction burial up to the amphibolite facies is ~ top-NW in present-day coordinates. Three amphibolite facies nappe units are distinguished, which may correspond to proximal and more distal parts of the former hyper-extended Iberian margin. The bottom and top nappes consist of continental material, while the middle nappe is largely made of mafic and ultramafic rocks. Top-NW shearing was coeval with the isoclinal and tight asymmetric folding of the formations. These structures were overprinted by upright folds and greenschist facies shear zones that still developed under compression. These contractional structures are cross-cut by ~ top-W shear zones associated with exhumation that show evidences of gradually decreasing P-T conditions during extension from ductile shearing to normal faulting. We show that the same protolith can be followed in amphibolite grade below and in low greenschists grade above the main extensional detachment. This demonstrates that the extensional detachment did not follow and reactivate exactly the former nappe contact between the Nevado-Fillabrides and Alpujárride complexes. Our single grain fusion 40Ar/39Ar ages on white micas show a range of 10 to 20 Ma in case of nappe contacts or extensional shear zones, while yield a significantly older, 25-40 Ma age cluster in case of a sample far away from the main shear zones in the core of the Nevado-Fillabrides dome. This age cluster could either represent excess Ar in the sample, or resetting due to a distinct tectono-metamorphic event that occurred prior to the Early Miocene subduction of the Nevado-Fillabrides complex. The latter case would require the reconsideration of recent tectonic reconstructions of the region.
Human environmental interactions during the Neolithization of the Ammer Valley: first results integrating paleo-ecological and bio-archaeological evidence
Authors: Heidgen Shaddai , Marinova Elena , Krauß Raiko , Nelle Oliver , Ebner Martin , Klingler Stefan , Miranda Tatiana , Böfinger Jörg , Stephan Elisabeth , Junginger Annett
Published: March 2020

The Upper Neckar and Ammer river valleys in southwestern Germany correspond to the southwestern limit of the overall distribution of the oldest Linear Bandkeramik (LBK) culture. More than 200 Neolithic sites are known from this region with one of the oldest sites located in the vicinity of the village Ammerbuch-Pfäffingen, around 10 km west of Tübingen, Germany. The archaeological record suggests that settlement activities occurred here between 7260 and 7110 cal BP (or 5310-5160 cal BC). Despite the various activities at the settling site itself, little is known about the environmental impact of the first settlers on the area, ranging from the introduction of farming and animal husbandry with impacts to the forests due to pasture and collection of wood, as well as possible control of water bodies. We here present the first results of a palynological study of two parallel, overlapping 8 m long sediment cores that were retrieved in 2018 from a shallow paleo-lake only a few hundred meters distant from the excavation site. The composite core allows environmental reconstruction of the area between 11540 and 7000 cal BP, based on six radiocarbon dates. Pollen analysis indicates mixed oak forests and an increase of light-demanding vegetation (i.e. Quercus, Corylus, Betula). Current analyses on micro- and macro-charcoal are going to reveal the natural or anthropogenic induced causes of paleo-fire events and Non-Pollen-Palynomorphs (NPP), including dung spores, unravel the possible presence of herbivores (including domestic ones) in the area. The results of the current study and its integration into the bioarchaeological record are relevant even beyond the region providing the usually rarely available paleoecological records from close proximity of an LBK site and thus deliver valuable insights on the environmental settings at the beginning of farming in central Europe.

 
Preliminary GRACE-FO gravity field solutions from Tongji University
Authors: Chen Qiujie , Shen Yunzhong , Zhang Xingfu , Kusche Jürgen
Published: March 2020

Due to the battery issue, the Gravity Recovery and Climate Experiment (GRACE) mission unfortunately came to an end in October 2017 after providing more than 15 years of mass transport information of our changing planet. To continue to monitoring the mass transport in the Earth system, the GRACE Follow-On (GRACE-FO) was launched in May 2018. As a new feature of GRACE-FO, a Laser Ranging Interferometer (LRI) was equipped to measure the inter-satellite range at a nanometer level. Since May 2019, GRACE-FO Level-1B observations have been made available to our community. Using the GRACE-FO Level-1B observations without laser ranging information, preliminary GRACE-FO gravity field solutions from Center for Space Research (CSR), GeoForschungsZentrum (GFZ), Jet Propulsion Laboratory (JPL) and Graz University of Technology have been released. Incorporating laser ranging observations into gravity field determination, a preliminary time series of GRACE-FO gravity field solutions has been derived from Tongji University in collaboration with University of Bonn. In this paper, the signal and noise of our gravity field solutions are analyzed and compared to those from other research groups. Our results show that the laser ranging observations with a sampling rate of 2s are able to improve gravity field solutions by about 7% in terms of geoid degree variances up to degree and order 96 as compared to the K-Band ranging data with a sampling rate of 5s.
A weather generator based on vine copulas and phase randomization for producing scenarios
Authors: Schlabing Dirk , Bárdossy András
Published: March 2020

Using weather generators to produce scenarios with changed statistics commonly involves the output of numerical climate models and/or leveraging the correlations in an observed data set. This contribution proposes vine copulas as a method to improve the latter in a parsimonious way. The vine copula construction flexibly models multivariate dependence structures as it breaks these down into pair-wise relationships that can be modelled individually with the wide variety of bivariate copula families. Setting up the vine tree carefully allows a user-supplied change in one specific variable, e.g. air temperature, to spread to the other simulated variables according to the fitted dependence structure.
In order not to increase dramatically the number of free parameters, the copula is only employed for time-invariant, inter-variate dependence, leaving all temporal and inter-site dependencies to Phase Randomization. Phase Randomization is a spectral method which generates "surrogate time series" that share their autocorrelation function with a source time series. It can be modified to handle cross-correlations in multivariate time series as well.
Precipitation occurrence and amounts are simulated in a joint fashion, using a latent variable constructed with information from other meteorological variable at the same locations.  The methodology will be illustrated with an example involving daily air temperature, precipitation, sunshine duration and relative humidity from measurement stations in southern Germany. 
Impact of cloud coverage on growth dynamics of Cedrela nebulosa from an Amazonian pre-montane forest in Central Ecuador
Authors: Vargas Danny , Pucha-Cofrep Darwin , Burneo Angélica , Carlosama Lisseth , Herrera Madison , Serrano Sheila , Cerna Marco , Jull A.J. Timothy , Molnár Mihály , Futó István , Horváth Anikó , Temovski Marjan , Palcsu László
Published: March 2020

The neotropical tree genus Cedrela (Meliaceae) had originated in dry forest under seasonal climates in North America, then spread to South America during the Oligocene/Early Miocene and finally adapted to deciduous forest in the Pliocene Epoch. At present, Cedrela comprises 17 species distributed in the Neotropics (24N-27S) and in Ecuador; the species Cedrela nebulosa (T.D.Penn. & Daza) generally develops in the altitudinal range of 1100-2400 m a.s.l. The town of Mera, Pastaza in Central Ecuador was the first lowland Amazonian site from which paleoecological data were acquired. It brought about the hypothesis of a 4.5 oC temperature depression during glacial times recently supported by a paleolimnological record in the area. However, despite the dry events during glacial periods there was not a loss of forest structure owing to the importance of cloud cover formation enhanced by the lower temperatures (Montoya et al., 2018).

Our research aims to study the role that cloud cover plays in the pre-montane forest of Mera, located at the Andean eastern flank (1º24'25 S, 78º03'10 W, 1200 m a.s.l) and its coupling with modern climate variations. It is expected that cloud cover will continue moving upwards and narrowing as temperature rises overriding its buffering effect against changes in precipitation, a scenario that threatens the forest stability achieved even during glacial periods. Dendroclimatological methods will be applied with trees of Cedrela nebulosa which receive moisture and constant temperature throughout the year. Interpretations of the phenomenon are expected to be drawn using oxygen isotopes in tree-ring cellulose (δ18OTR) and precipitation (δ18OW), as well as air temperature (T), for which monitoring has been established in the study area. The formation of annual rings in the species has been preliminary validated by radiocarbon dating (14C) using the bomb peak.

The research was supported by the European Union and the State of Hungary, co-financed by the European Regional Development Fund in the project of GINOP-2.3.2-15-2016-00009 ‘ICER’.

Reference: Montoya et al., 2018. Front. Plant Sci., 9, 196; doi: 10.3389/fpls.2018.00196
Ozone variability and trends in the UTLS derived from the IAGOS- CARIBIC observatory using JETPAC
Authors: Boenisch Harald , Zahn Andreas , Millan Luis
Published: March 2020

The CARIBIC (Civil  Aircraft  for  the  Regular  Investigation  of the atmosphere Based on an 
Instrumented Container) project is part of the a European research infrastructure IAGOS (In-
Service Aircraft for a Global Observing System) making regular in-situ measurements of more 
than 100 atmospheric constituents, include ozone and water vapour, on-board of an in-service 
passenger  aircraft  operated  by  Lufthansa.  The  dataset  of  the  IAGOS-CARIBIC  is  therefore 
ideally suited as a testbed for the SPARC (Stratosphere-troposphere Processes And their Role 
in Climate) activity OCTAV-UTLS (Observed Composition Trends And Variability in the Upper 
Troposphere and Lower Stratosphere). One key aspect, shown here as work in progress, is to 
develop, define and apply common metrics for the comparison of different UTLS datasets 
using a variety of meteorological coordinate systems derived from reanalysis datasets. The 
focus here is on the variability of ozone in the upper troposphere and lower stratosphere 
(UTLS) on interannual and seasonal timescales and the observed trends. The in-situ ozone 
measurements by IAGOS-CARIBIC are analysed relative to different tropopause definitions 
and coordinate systems. All these meteorological information applied here are produced with 
the JETPAC tool ‒ Jet and Tropopause Products for Analysis and Characterization (Manney et 
al., 2011).
Column experiments to investigate the fate of per- and polyfluorinated alkyl substances (PFAS) in the subsurface during soil stabilisation with activated carbons.
Authors: Niarchos Georgios , Georgii Linnea , Berggren Kleja Dan , Ahrens Lutz , Fagerlund Fritjof
Published: March 2020

Remediation of sites contaminated with per- and polyfluorinated alkyl substances (PFAS) is key to reduce the contamination of drinking water sources and human exposure. PFAS use is increasingly being restricted worldwide resulting in reduction of point sources; however, legacy plumes are still posing a threat due to the persistence of these chemicals against degradation. One of the most widely studied soil remediation techniques for PFAS is stabilisation (fixation) which results in the long-term entrapment of the contaminants with the addition of activated carbons in the subsurface, aiming to restrict their leaching from soil to groundwater. In relation to this, the aim of this study was to identify the leaching behaviour of various PFAS in a treatment scenario using activated carbons. Silt loam soil sampled from central Sweden was tested, as well as a mixture of the soil with powdered activated carbon (PAC) and colloidal activated carbon (CAC) at 4% w/w concentration. Spiked groundwater was prepared with 21 PFAS, at a concentration of 2.4 μg mL-1 for each individual compound. The leaching of PFAS from the solid phase was simulated using column experiments in saturated conditions. Additionally, the partitioning behaviour of the substances with increasing concentration was studied through the definition of sorption isotherms for each matrix. For this purpose, batch-shaking tests were performed, and sorption isotherms were defined by fitting the data with the Freundlich and Langmuir models, using five concentration points in the range of 0.1-100 μg mL-1 for the sum of PFAS. Analysis of the compounds was conducted using high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). Preliminary results from the batch tests show significantly increased sorption in soil amended with activated carbons compared to the untreated soil and a better overall performance of CAC compared to PAC. The study is expected to provide essential information on the efficiency and longevity of stabilisation with activated carbons as a remediation strategy for PFAS-contaminated soils.
Human thermal comfort in Local climate zones of Berlin
Authors: Langer Ines , Pasternack Alexander , Ulbrich Uwe
Published: March 2020

Urban areas show higher nocturnal temperature comparing to rural areas, which is denoted by urban heat island. This effect can intensify the impact of global warming in urban areas especially during heat waves, that leads to higher energy demand for cooling the building and higher thermal stress for residents.  

The aim of this study is to identify the Urban Heat Island (UHI) effect during the heat spell 2018 and 2019 in order to calculated human thermal comfort for Berlin. Berlin, the capital city of Germany covers an area of 892km2 and its population is growing, therefore more residential areas will be planned in future through higher building. The methodology of this research is to divide Berlin into Local Climate Zones (LCZ's) regarding the concept of Stewart & Oke (2012). Then to evaluate the accuracy of this concept using 30 microclimate stations. Estimating the magnitude of urban heat island and its seasonal changes in combination with human thermal perception in different LCZ during summer time is another objective of this research. 

Ten LCZ's for Berlin were selected, as class 1 (compact high rise), class 3 (compact low rise), class 7 (lightweight low-rise), class C (bush, scrub), class E (bare rock or paved) and class F (bare soil or sand) don't exist in Berlin. Class A (dense trees) is with a fraction of 18.6% in a good agreement with the percentage of dense trees reported from the city administration of Berlin (18.4%), class G (water) has a coverage of 5.1% through our classification instead of 6.7% reported by the city administration. In summary, the LCZ 1-10 cover 59.3% (more than half) of the city area.

Regarding temperature measurements, which represent a hot summer day with calm wind and clear sky the difference of Local Climate Zones will be calculated and the temperature variability in every LCZ's regarding sky view factor values show the hot spot of the city.

The vulnerability of LCZ's to heat stress will be ranked and discussed regarding ventilation and other factors.

 

Literature

Matzarakis, A. Mayer, H., Iziomon, M. (1999) Applications of a universal thermal index: Physiological equivalent temperature: Intern. J. of Biomet 43 (2), 76-84.

Stewart, I.D., Oke, T.R. (2012) Local climate zones for urban temperature studies. Bull. Amer. Meteor. Soc. 93 1879-1900. DOI: 10.1175/BAMS-D-11-00019.1.

 
The Changed Sign of Swell Coherent Stress During Swell Conditions
Authors: Pan Wei , Zou Zhongshui , Song Jinbao
Published: March 2020

Data measured by ultrasonic anemometer moored at a fixed platform located in South China Sea has been used to analyze turbulence within wave boundary layer. Compared to wind seas, it can be found a dominant area in power spectra, cospectra and Ogive curves under swell conditions from the measurements at 8 m height above sea surface, which is consistent with earlier studies. Our result also shows that the cospectra have both negative and positive regions, which represent the upward and downward momentum induced by swell waves. The wave coherent stress derived from the cospectra shows that it is more larger than the traditional method, implying earlier studies have greatly underestimated the stress of swell. Our study also found that the change of sign of swell coherent stress was related to the wave age, i.e. for cp/u* ≥ 60, swell induced the upward momentum, for cp/u* < 60, vice versa.  
Developing Active Learners Based on Education for Sustainable Development
Authors: Nakamura Shuji
Published: March 2020

The subject of “Comprehensive Geography” aims to cultivate student attitudes leading them to enthusiastically pursue global and regional issues by “considering some geographic contemporary issues from relationships between environments and human activities in order to build a sustainable society” from ESD’s (Education for Sustainable Development) perspective. I hope this report, developed in collaboration between teachers from Japan and the USA, showcases an example of how to incorporate the principles of ESD in a way that motivates students. Through PBL (Project Based Learning) experiences like this one, I hope to help students become leaders in creating a more sustainable society.

 

Also, based on ESD, I have developed and implemented a framework for nurturing active learners in not only Geography classes but also through “integrated inquiry learning.” Specifically, my lesson plans often use the KCJ (the Knowledge Constructive Jigsaw Method) or PBL, and I have gradually tried to develop active learners by designing this framework with ESD’s viewpoint in mind.

 

As a result, the development of attitudes has been linked as a factor to solve problems and inquiries about some global and regional issues. Therefore, it was recognized that ESD contributes to the development of active learners and the formation of emergent learning communities.

 

In this assembly, I will show two concrete cases, one is the PBL on the Urban Design Project being applied to the Smart Growth Principles. This case study especially showed the importance of their own will to participate in and solve these social issues through presenting a self-made urban master plan.

 

Another case is the KCJ on contemporary problem-solving at Tottori Sand Dunes. This case showed that the ability to find a “new” problem could be acquired through comprehending this complexity, by going back to the past and forth to the future.
Utilizing time-lapse hydraulic tomography to characterize the subsurface changes during methane and heat injection experiments
Authors: Hu Linwei , Somogyvári Márk , Bauer Sebastian
Published: March 2020

Storage options for the energy storage in the subsurface includes the injection and storage of the “energy gas” (e.g., methane, hydrogen, compressed air) or thermal water into the underground formations. The heterogeneous structure of the storage formations could play a crucial role on the potential storage capacity, as well as the formulation of post treatment strategy. Hence, innovative techniques are required for characterizing the high-resolution formation heterogeneity and monitoring the gas or heat plume distribution in the subsurface after their injections.  Previous studies have shown that flow properties can vary as the gas or thermal water being injected into the aquifer. In this study, we propose a time-lapse hydraulic tomography (HT) method for characterizing the baseline hydraulic information and depicting the hydraulic property changes through a series of cross-well pumping tests. These tests were implemented in two pilot sites for methane and hot water injection tests at Wittstock, Germany. In order to generate a three-dimensional tomographical configuration, each pumping test was conducted at certain depth in a testing well, accompanying with multiple observation points at other wells. Depth-variant pumping and observation segments were formed by the double-packer system. As a result, we achieved 198 and 135 baseline drawdown curves for the methane and heat sites, respectively. For these measured data, we initially evaluated the effective hydraulic conductivity and specific storage of the aquifer according to certain analytical fitting methods. Furthermore, the vertical anisotropy of the hydraulic conductivity was also estimated. Sequentially, the fitted hydraulic parameters and analytical drawdown curves were utilized for correcting the well skin effects on hydraulic traveltimes and attenuations, as they have an unneglectable impact on them.  The corrected hydraulic traveltimes and attenuations were used for the inversion of the baseline hydraulic diffusivity and specific storage, respectively. Hydraulic conductivity distribution was then estimated through these two parameters. After we achieved the baseline information, HT was executed again by repeating the tomographical pumping tests after methane and hot water injections. The same data processing and inversion techniques were applied to the drawdown curves derived from the post-injection period. Inverted hydraulic diffusivity, specific storage, and hydraulic conductivity were compared to the baseline inversion results. Changes on these hydraulic properties could provide the information of the spatial distribution of methane or heat plume.
Waveguide for Rossby waves in the Antarctic Circumpolar current based on the altimetry data
Authors: Frolova Anastasiia , Belonenko Tatyana
Published: March 2020

Rossby waves in the ocean play a crucial role in large-scale ocean circulation and global climate. However, the interaction of Rossby waves with large-scale currents in the ocean is still a relatively little studied issue. The Antarctic Circumpolar Current (ACC) is the largest ocean current in the World Ocean. The ACC is a waveguide for Rossby waves where wave kinetic energy is captured by jets, and where Rossby waves interact with the flow. The purpose of this research is to analyze a manifestation of Rossby waves in the ACC based on satellite altimetry data. We propose a new approach to determining the boundaries of the waveguide. We analyze the variability of sea level anomalies and examine the latitude where the zonal velocity of Rossby waves is zero. For calculating Rossby waves velocities we use Radon and cross-correlation methods. We detect the Northern and the Southern Waveguide Boundaries for the ACC and compare them to the climatological fronts in the ACC. The linear theory of Rossby waves doesn’t work within the waveguide due to that we should consider nonlinear in the long-wave approximation. It follows from the theory of shallow water that nonlinearity in the long-wave approximation compensates exactly for the Doppler shift. The nonlinear dispersion equation agrees well with altimetry data.

The investigation is supported by the Russian Foundation for Basic Research grant (17-05-00034).
Application of portfolio theory to the wind-solar energy mix in Spain: climate-related risks and opportunities
Authors: Maimó-Far Aina , Tantet Alexis , Homar Víctor , Drobinski Philippe
Published: March 2020

Non-hydroelectric renewable energy sources (RES) are the fastest growing energy generation technologies in terms of new capacity and their penetration is expected to double in the next 20 years. More than half of this growth is expected to come from wind power. However, given the variable nature of RES production linked to climate variability and the need for a constant supply-demand balance, increasing penetration of renewables raises structural, technological and economical issues. In Spain, the correlation of solar and wind climate potential with the seasonal fluctuation of electricity consumption, associated mostly with tourism activity, allows for some ambitious renewable penetration scenarios. This work aims at identifying optimal energy mix scenarios that maximize RES penetration while minimizing distribution risk, using the Markowitz modern portfolio theory as a starting point. We apply the e4clim model to the Spanish electricity system, using reanalysis and electricity data in order to produce scenarios for optimal geographical and technological distribution of RES installed capacity. We conduct a mean-risk analysis and discuss the geographical distribution for the most relevant optimal scenarios. We also provide an interpretation of the optimal RES penetration results in terms of the regional climatic characteristics of Spain. Beyond the large potential of the regional climates of Spain to exploit RES technologies, optimal scenario results reveal interesting regional differences with respect to the current installed capacities, which can be linked to economic and regulatory regional contexts.
Impact of Doppler radar reflectivity and velocity data assimilation on the quality of precipitation forecasting in Belarus in different seasons
Authors: Zaiko Palina , Barodka Siarhei , Krasouski Aliaksandr
Published: March 2020

Heavy precipitation forecast remains one of the biggest problems in numerical weather prediction. Modern remote sensing systems allow tracking of rapidly developing convective processes and provide additional data for numerical weather models practically in real time. Assimilation of Doppler weather radar data also allows to specify the position and intensity of convective processes in atmospheric numerical models.

The primary objective of this study is to evaluate the impact of Doppler  radar reflectivity and velocity assimilation in the WRF-ARW mesoscale model for the territory of Belarus in different seasons of the year. Specifically, we focus on the short-range numerical forecasting of mesoscale convective systems passage over the territory of Belarus in 2017-2019 with assimilated radar data.

Proceeding with weather radar observations available for our cases, we first perform the necessary processing of the raw radar data to eliminate noise, reflections and other kinds of clutter. For identification of non-meteorological noise fuzzy echo classification was used. Then we use the WRF-DA (3D-Var) system to assimilate the processed radar observations from 3 Belarusian Doppler weather radar in the WRF model. Assimilating both radar reflectivity and radial velocity data in the model we aim to better represent not only the distribution of clouds and their moisture content, but also the detailed dynamical aspects of convective circulation. Finally, we analyze WRF modelling output obtained with assimilated radar data and compare it with available meteorological observations and with other model runs (including control runs with no data assimilation or with assimilation of conventional weather stations data only), paying special attention to the accuracy of precipitation forecast 12 hours in advance.
Gravity effect of Alpine slab segments based on geophysical and petrological modelling
Authors: Lowe Maximilian , Ebbing Jörg , El-Sharkawy Amr , Meier Thomas
Published: March 2020

The direction and location of subducting slab segments in the Alpine area is highly debated.  Here, we use seismic crustal depth estimates and different upper mantle tomographies to define hypotheses for the geometry of the subducting slab segments. Based on a new surface wave tomography of the upper mantle in the Alpine region, we also include a new hypothesis with a long Eurasian slab in the central Alps, a short slab segment in the western Alps, and bivergent subduction in the eastern Alps. In addition, we consider the south-dipping slab segment beneath the northern Apennines.  

Next, we study the possible slab related effects of the various considered slab geometries on the gravity field. Specifically, we calculate the gravity effects at the surface and at satellite altitude. In addition to the vertical gravity effect we also show gravity gradients. Two approaches are compared.  First, we convert seismic velocities directly to density using accepted conversion factors. Such direct conversion results in relatively scattered gravity anomalies. In the second approach, we assign density contrasts to predefined slab geometries. Starting from simple models with a constant slab density, we increase the complexity by considering temperature and pressure related density changes according to mantle composition. For such models, the density contrast of the slabs to the ambient mantle diminishes with depth. These models based on predefined slab geometries allow to analyse contributions by the different slab segments independently in greater detail. Combining the slab models with recent 3D crustal models of the Alps is needed in order to establish realistic density models of the Alpine realm for geodynamic applications.
Discrete element methods and continuum models in bedload transport
Authors: Frey Philippe , Rousseau Hugo , Chassagne Rémi , Maurin Raphaël , Chauchat Julien
Published: March 2020

An ongoing research effort is reported on sediment transport multi-scale modeling in the framework of the ANR project SegSed ‘Size SEGregation in SEDiment transport’. Using a coupled fluid-discrete element model, a variety of numerical experiments were carried out in 2D and 3D bedload configurations studying the dynamics of the depth structure of mono- and bidisperse mixtures. Such models allow access to internal processes in the case of grain sorting and to variables very difficult to measure in the laboratory such as particle shear stress and rate. These variables are the key ingredients to derive constitutive relationships. Such a relationship inspired by one used in dry granular flows was successfully implemented in a Eulerian-Eulerian two-phase flow model. Progress is being made with a multi-class model where the momentum balance for each grain size class should be inferred by discrete element modelling. Ultimately, such studies could be useful to improve Exner-shallow water-type models in particular when grain sorting is considered.
Impact of electron density values from space-geodetic observation techniques on thermospheric density models
Authors: Corbin Armin , Vielberg Kristin , Schmidt Michael , Kusche Jürgen
Published: March 2020

The neutral density in the thermosphere is directly related to the atmospheric drag acceleration acting on satellites. In fact, the atmospheric drag acceleration, is the largest non-gravitational perturbation for satellites below 1000 km that has to be considered for precise orbit determination. There are several global empirical and physical models providing the neutral density in the thermosphere. However, there are significant differences between the modeled neutral densities and densities observed via accelerometers. More precise thermospheric density models are required for improving drag modeling as well as orbit determination. We study the coupling between ionosphere and thermosphere based on observations and model outputs of the Thermosphere Ionosphere Electrodynamics General Circulation Model (TIE-GCM). At first, we analyse the model’s representation of the coupling using electron and neutral densities. In comparison, we study the coupling based on observations, i.e., accelerometer-derived neutral densities and electron densities from a 4D electron density model based on GNSS and satellite altimetry data as well as radio occultation measurements. We expect that increased electron densities can be related to increased neutral densities. This is indicated for example by a correlation of approximately 55% between the neutral densities and the electron densities computed by the TIE-GCM. Finally, we investigate whether neutral density simulations fit better to in-situ densities from accelerometry when electron densities are assimilated.