bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Simulations of Convective Cloud Merging Processes at Different Development Stages
Authors: Zhai Jing , Huang Yong
Published: March 2020

Mergers of cells in a severe convective weather on 22 July 2008 are simulated and analyzed by Mesoscale Model 5 (referred to as MM5）and radar network data. Observation results show that, the horizontal scale of the echo above 30 dBZ, which represent the small cells, is about 10 km, and the small cells that the echo centers are 20km apart merge into a larger cell at dozens of km of horizontal scale.. Mergers begin from the peripheral radar echo, and then strong central radar echo merges at the low level, at last, the acreage of strong radar echo increases after the merger. The contrast between the observations and the simulation results shows that they are consistent. Analysis on the simulation results of two kinds of cell mergers at different development stages based on the third network model output shows that, while the cell pairs are with almost the same intensity, cells would develop after merger; while one of the cell pairs is in stronger development however the other one weaker, the stronger cell would keep on development and the weaker cell would die out. During the merger, a new cloud water center appears in the low convergence region between the cell pairs, and would replace the two cloud water centers of the former cells, or the new cloud water center would merger with one of the old cloud water centers while the other old cloud water center disappears. The analysis of the simulation results also shows that, the cell merger would lead to the cloud top lifting and the increase in the radar echo, content of cloud water and ice, surface rainfall.
From sink to source: extracting onshore erosion signals preserved in offshore thermochronometric data
Authors: Gallagher Kerry , Wildman Mark
Published: March 2020

Products of onshore passive continental margin erosion are preserved in offshore sedimentary basins. Therefore, these basins potentially hold a recoverable record of onshore erosion. We present a suite of apatite fission track (AFT) data for 13 borehole samples from the southern Walvis basin, offshore Namibia. All of the samples show AFT central ages older or similar to their respective stratigraphic ages, and many single grain ages are older. These data show that none of the samples has been totally annealed post-deposition. Furthermore, the large dispersion in single grains ages in some samples suggests multiple age components. A lack of obvious correlation to compositional proxies implies this dispersion is related to different source regions. Using Bayesian mixture modelling we classify single grain ages from a given sample to particular age components to create ‘subsamples’. Subsequently, we jointly invert the entire dataset of subsamples to obtain a consistent thermal history for the well location. For each sample, the post-depositional thermal history is required to be the same for all age components, but each component has an independent pre-depositional thermal history. With this approach we can resolve pre- and post-depositional thermal events and identify potential changes in sediment provenance over time. In the example we present from offshore Namibia, we constrain the erosional evolution of the continental margin over a longer timescale than has been possible using onshore AFT thermochronological data and or offshore sediment volumes.

 
Scale-dependent analysis of climate model biases in relation to dynamics
Authors: Kosovelj Katarina , Žagar Nedjeljka
Published: March 2020

The assessment of climate model biases in an important part of their validation, in particular with respect to the application of the outputs of global models as lateral boundaries in regional climate models. The coupled nature of thermodynamics and circulation asks for their simultaneous treatment in the model bias analysis. This can be achieved by applying the normal-mode decomposition of model outputs and reanalysis that provides biases associated with the two dominant atmospheric regimes, the Rossby (or balanced) and inertia-gravity (or unbalanced) regime. The regime decomposition provides the spectrum of bias in terms of zonal wavenumbers, meridional modes and vertical modes. This can be especially useful in the tropics, where the Rossby and IG regimes are difficult to separate and biases in simulated circulation, just like the circulation itself, have global impacts. 

The method is applied to the intermediate complexity climate model SPEEDY. Fifty-year long simulations  are performed in AMIP-mode with the prescribed SST. Biases are computed with respect to ERA-20C  upscaled to the resolution of SPEEDY (T30L8). We evaluate biases both in modal and physical space and study regional biases associated with the  balanced and unbalanced components of circulation. This work thus expands the results presented by Žagar et al. (2019, Clim. Dyn.) to the two regimes-related bias analysis..

The results show that the bias is strongly scale dependent, just like the simulated variability. The largest biases in SPEEDY are at planetary scales (waveumbers 0-3). Biases associated with the extratropical Rossby modes explain more than the half of bias variance. The Rossby n=1 mode is a single mode with the largest bias variance in balanced circulation whereas the Kelvin wave contains the largest bias among the IG modes. These biases are shown to originate mostly in the stratosphere and the upper-troposphere westerlies in the Southern hemisphere. 
Climate change impact assessment of sub-alpine vegetation in national park using CMIP5 GCMs
Authors: Kim Jaeuk , Jung Huicheul , Yu Insang , Lee Sung-Hun
Published: March 2020

In South Korea, national parks occupy the largest area among the protected areas designated to protect biodiversity and ecosystem. Among the 17 mountainous national parks, the vegetation in alpine and sub-alpine regions are very vulnerable to climate change. The objective of this study is to estimate the impact of climate change on sub-alpine vegetation considering uncertainties of future climate and the species distribution method. Observation data were gridded to 3 km spatial resolution from 1981 to 2010 using the Improved GIS-based Registry Model(IDW-IGISRM) based on the Inverse distance weighting(IDW). To reduce future uncertainty of climate change, future climate scenarios of RCP 4.5 and RCP 8.5 of CMIP5 GCM were utilized. In order to increase the spatial resolution of the GCM, Simple Quantile Mapping, one of the various bias correction and downscaling techniques, was applied. Bioclim DB, a bioclimatic variable considering temperature and moisture conditions, was established using monthly maximum temperature, minimum temperature and precipitation data among detailed GCM data. Impact assessment was held using Biomod2 of R package, for endangered sub-alpine vegetation in the National Forest Inventory(NFI). Verification of the species distribution models were carried out using AUC(Area Under the Curve) and TSS(True Skill Statistics). The result of this study is expected to be utilized for protected area management measures for biodiversity conservation in forests.

※ This work was supported by Korea Environment Industry & Technology Institute(KEITI) through Climate Change Correspondence Program, funded by Korea Ministry of Environment(MOE)(2018001310004).
A synthesis-analysis of winter oilseed rape (Brassica napus L.) yield response to planting density under intensive cropping system
Authors: Cong Rihuan , Zhang Zhi , Lu Jianwei
Published: March 2020

Background: Optimal yield is dependent on the collocations between plant population and individual growth. High plant populations for direct sown winter oilseed rape would be a prevailing way to achieve high yield under intensive cropping systems.

Results: We investigated the oilseed rape yield response to planting density while considering the productivity environment, nitrogen (N) fertilizer, and sowing date. A synthesis-analysis was conducted by collecting the density-yield data in the field experiments of oilseed rape from 2000 to 2016 in China. The population yield response to different planting density levels could be described by a quadratic model, with threshold value of 45-60 plant m-2, and excessive density may cause yield loss as the weak individual growth. High planting density has no remarkable influence on the attainable population yield due to the decreasing individual potential yield. The population yield increment capacity by the increasing planting density was higher in medium yield environment (i.e., average yield at 1500-2500 kg ha-1). The planting density presented remarkably effect on population yield after the N limitation was relieved. Increasing planting density at 104 plants per hectare was equivalent to apply 1.17 kg N fertilizer on population yield, ranging from 0.42 kg to 4.76 kg under different yield environment levels. Yield loss caused by unsuitable sowing date (especially for the late sowing) could be compensated by increasing planting density.

Conclusion: Planting density played a crucial role in cooperating the other management practices. Optimizing the allocation of plant population and individual growth, establishing target plant phenotype under high planting density would help to achieve high population yield.
Tephra-based time-markers from the Last Glacial Period recorded in the North Atlantic: an emerging tool for an east-west synchronization of paleoclimate records
Authors: Rutledal Sunniva , Berben Sarah M. P. , Dokken Trond M. , Tisserand Amandine A. , Jansen Eystein
Published: March 2020

Geochemically distinct volcanic ash (tephra) deposits have the potential to act as a key geochronological tool to independently synchronize independent paleoclimate archives. Recent advances in the detection of invisible (crypto) tephra have led to the ongoing development of regional tephra frameworks. These frameworks provide an overview of the spatial coverage of existing geochemically distinct tephra horizons attributed to dated eruptions. Hence, these developing frameworks produce an essential tool for precise correlation of different and/or disparate climate archives within a certain region. Here, using cryptotephra analysis, we investigate the potential occurrence of two well-known tephra horizons from the Last Glacial Period (i.e. FMAZ II-1 (26.7 ka b2k) and NAAZ II (II-RHY-1) (55.3 ka b2k)), in five different marine sediment cores from the Denmark Strait, as well as the Nordic, Irminger and Labrador Seas. We have successfully identified FMAZ II-1 in both the Nordic and Irminger Seas. Even more so, this study presents the first identification of an isochronous FMAZ II-1 horizon detected in the Irminger Sea. This clearly demonstrates an increased potential for tephrochronology within this region. In addition, NAAZ II (II-RHY-1) was also recorded in the Denmark Strait, the Irminger Sea and the Labrador Sea. Using those identified tephra time-markers allows us to discuss the synchronization of paleoclimate records retrieved from the in this study and previously investigated marine sediment cores. We focus on both time periods when the tephra time-markers were deposited (i.e. Greenland Stadial-3 (FMAZ II-1) and Greenland Interstadial-15 (NAAZ II (II-RHY-1)) with the aim to provide synchronized records of ocean temperature and salinity changes. Therefore, we use Mg/Ca ratios of benthic foraminifera and stable isotopes (d18O & d13C) of benthic and planktonic foraminifera. By coupling the paleoclimatic information with the identified tephra time-markers, we provide a robust overview of the climatic conditions in the North Atlantic Ocean during these two time periods.
Quantitative texture analysis by neutron diffraction in deformed crystalline aggregates: Contín Shear Zone, Morais Complex, N Portugal.
Authors: Durán Oreja Manuela , Malecki Jeremie , Gómez Barreiro Juan
Published: March 2020

Two samples of mylonitic-ultramylonitic ortogneisses collected along the Contín shear zone were investigated for crystal preferred orientation and seismic anisotropy. Neutron diffraction data obtained at the D1B beamline at ILL (Institute Laue-Langevin, Grenoble) were analyzed with the Rietveld method as implemented in the code MAUD, to obtain the orientation distribution functions (ODF) of the principal phases (quartz, K-feldspar, plagioclase, phlogopite, muscovite and riebeckite). Texture and microstructure are compatible with the plastic deformation of the aggregates under medium to low-temperature conditions. Kinematic analysis supports a top-to-the SE sense of shear, suggesting a thrust character. Using preferred orientation data and single crystal elastic tensors, P and S-waves velocities and elastic anisotropy have been calculated. We have explored the role of several factors controlling the elastic properties of rocks, particularly the role of strain state and mineral changes in a shear zone. Those factors have a direct impact on the medium impedance and consequently on the interphase reflectivity. P-wave velocities, S-wave splitting and anisotropy increase with muscovite content. Seismic anisotropy is linked with the texture symmetry, which can result in large deviations between actual anisotropy and that measured along Cartesian XYZ sample directions (lineation/foliation reference frame). This is significant for the prediction and interpretation of seismic data. (Research support CGL2016-78560-P)
MOTEDAS Century Database. Thermal amplitude trends in Spanish mainland (1916-2015).
Authors: Gonzalez-Hidalgo Jose Carlos , Sandonís-Pozo Leire , Peña-Angulo Dhais , Brunetti Michele , Beguería Santiago
Published: March 2020

There exists a debate in the scientific research about the evolution of daily thermal amplitude (DTR) along the 20th century, Id est: if the trend in minimum temperatures (night time) has been more pronounced than that of maximum temperatures (daily time). General speaking it has been accepted that until the 1980´s the trend of the DTR has been negative and then changes to positive ones. Notwithstanding, regional and sub-regional dataset developed during the last decades has shown that DTR behaviour is high variable. It has been suggested that the Iberian Peninsula, because of its geographical location (latitude and position between two contrasted water masses), is one of the places in witch climate research could find results that anticipate future global climate conditions.

The new dataset MOTEDAS_Century (MOnthly TEmperature DAtaset of Spain) combines data from the Spanish national meteorological office (AEMET) archives with data rescued from annual books spanning the first decades of the 20th Century. This dataset allowed us to produce a high resolution (10x10 km) grid of minimum and maximum temperatures spanning over the last century (1916-2015). In the present research we will show a spatial analysis of the DTR (Tmax-Tmin) evolution by using moving windows from the total period (1916-2015) to a minimum time span of twenty years (1996-2015). Trends were calculated at monthly scale at each pixel series by means of a pre-whitened Mann-Kendall test in order to determine the sign and significance of trends.

The main results of the analysis are: i) trends were more pronounced for minimum temperature than maximum temperatures during warm months (July, August and September) in the southern and Mediterranean coastland; ii) the significant increasing trend of DTR disappears since the middle of the 1980´s; iii) at present, we only detect significant trends of DTR in December.
Stereoselectivity in Atmospheric Autoxidation
Authors: Møller Kristian H. , Praske Eric , Xu Lu , Crounse John D. , Bates Kelvin H. , Wennberg Paul O. , Kjaergaard Henrik G.
Published: March 2020

The importance of peroxy radical hydrogen shift reactions in the atmosphere has gained acceptance in recent years. Recent theoretical calculations have suggested that these can be stereoselective i.e. that different stereoisomers react with significantly different rate coefficients. Combining experiments (GC-CIMS) with high-level calculations (MC-TST), we show that two hydroxy peroxy radical diastereomers formed in the oxidation of crotonaldehyde have rate coefficients for their peroxy radical hydrogen shift reactions that differ by more than a factor of 10. The difference is large enough that under urban atmospheric conditions, one diastereomer would react primarily by the unimolecular H-shift, while the other would react mainly by bimolecular reactions leading to diastreomeric enhancement of the products.

For a large set of peroxy radical hydrogen shift reactions in the oxidation of isoprene, the stereospecific rate coefficients are calculated to assess the global importance of this phenomenon in the atmosphere.  These calculated rate coefficients are implemented into the global chemistry-transport model GEOS-Chem to model the effect. Results show that more than 30 % of all isoprene molecules emitted undergo a minimum of one peroxy radical hydrogen shift reaction during its oxidation. Furthermore, the results show that the different diastereomers may react with rate coefficients differing by up to almost a factor of 1000, highlighting how important it is to account for this phenomenon.
Analyzing trends in Land Surface Temperature using remotely sensed time series data and the BFAST method
Authors: Gemitzi Alexandra , Falalakis George
Published: March 2020

The present work deals with the time series analysis of remotely sensed Moderate Resolution Imaging Spectroradiometer (MODIS) Land Surface Temperature (LST). While many works have been published concerning the trends of nighttime and daytime LST at the regional or local scale, little attention has been paid to structural changes observed within the LST time series in various sub-periods. This could be of much interest not only for climate studies but also for unveiling the possible relation between natural disasters such as wildfires and global changes. In this work we tested the hypothesis of a constant trend in LST time series from 2000 to 2019 and highlighted the existence of periods with changing trends. The methodology was applied in an area of approximately 17.000 km2 located in NE Greece and South Bulgaria. The nighttime and daytime LST time series data were initially subjected to a gap filling algorithm to account for missing values and were then aggregated at the catchment level. Furthermore, LST time series were analyzed using the Breaks For Additive Season and Trend (BFAST) method. Results indicated that an abrupt change in both nighttime and daytime LST trends was observed in all examined time series, indicating a transition from a decreasing LST regime from 2002 to 2006 to an abrupt increasing thereafter until today. An initial comparison with the existing inventory of wildfires in the area for the last 20 years indicated an increase of wildfire events which coincides with the LST breakpoint, indicating thus possible connections between rising LST and wildfire events.
CRDS-based dissolved N₂O & CH₄ measurement system
Authors: Kim Il-Nam , Kim Seong-Su , Park Ki-Tae , Lim Jae-Hyun
Published: March 2020

 Gas chromatography (GC) is the most commonly used analytical equipment for tracer gas measurements. However, high performance equipment such as cavity ring-down spectrometer (CRDS) has been developed and currently become commercially available (G2308, PICARRO). CRDS is optical spectrometer to measure tracer gas, and its principal is that determines the gas concentration through the rate of decay of the optical signal. The great advantage of using CRDS is that not required too many material, time, and easy to handle than GC system. In general, CRDS is used for continuous measurement, which requires a large amount of gas for quantification. So, we have modified CRDS system to measure small amount of N2O/CH4 gases which is extracted from seawater samples using headspace method, and in turn have tested in various marine environments from coastal regions to open oceans. As a result, we have obtained highly accurate concentrations of dissolved N2O & CH4 gases, suggesting that the system would be useful to study dynamics of climate-relevant trace gases.
Analysis of Subdaily Meteorological Measurements by Louis Morin in the Late Maunder Minimum 1665 – 1713 in Paris
Authors: Pliemon Thomas , Foelsche Ulrich , Rohr Christian , Pfister Christian
Published: March 2020

Based on copies of the original data (source: Oeschger Center for Climate Change Research) we perform climate reconstructions for Paris. The focus lies on the following meteorological variables: temperature, cloudiness, moving direction of clouds and precipitation. We assess the early instrumental temperature dataset with state of the art statistical methods to get further knowledge of inhomogeneities. There are already several studies showing monthly and yearly means of the temperature, but a detailed statistical analysis based on the original measurements has not been done yet. Due to the lack of metadata, we do a qualitative analysis. With rare contemporary time series, like the CET (Central England Temperature), and proxydata, like grape harvest dates, we attempt to make a quantitative statement. We analyse and discuss the documentary datasets of the cloudiness and the moving direction of the clouds relating to the cooling in the Late Maunder Minimum. Because of the subjective character of documentary records, we compare these results with available data from former publications. Precipitation is given in terms of intensity and duration. We calculate indices like rainfall frequency and average rainfall per year/season/month.
Coupled multiphase flow and geomechanics simulation of hydrate dissociation using FVM-FEM co-located variables arrangement
Authors: Samala Rahul , Chaudhuri Abhijit
Published: March 2020

Natural gas hydrates, which are ice like crystalline solids, contain tremendous amount of potential hydrocarbon gas. Gas recovery through hydrate dissociation can be achieved through depressurization, inhibitor injection and thermal stimulation. The hydrate dissociation by depressurization involves significant pressure and temperature gradients as the dissociation process is highly endothermic. The destabilization of solid hydrate into fluid constituents causes loss of cementation which can alter the stress field which in turn changes the porosity and permeability of the hydrate bearing medium causing subsidence. In the present study, a thermo-hydro-mechanical-chemical (THMC) coupled numerical simulator is developed accounting for the hydrate phase change kinetics, non-isothermal multiphase flow and geomechanics. The point centered or node centered finite volume method is used for space discretization of flow and energy equations while the finite element method is used for stress equilibrium equation. This procedure requires the flow and mechanics variables to be co-located. The finite volumes are constructed around the flow variables defined at nodes while the finite element is defined by the corner nodes. The volumetric strain rate term in the flow equations, which couples the flow and geomechanics equations, is evaluated by interpolating the volumetric strains calculated over the finite elements to the finite volumes. Our simulations show that this procedure results in a stable convergence of the solution without the need for any stabilizing terms due to co-located variable arrangement. Our simulations also show that the iterative coupled approach, where the flow and geomechanics equations are solved separately and sequentially, gives stable convergence without any additional split terms due to sequential but iterative solving of the coupled equations.
Low-Cost Underwater Sound Recorder for coastal applications.
Authors: Cafaro Valentina , Terribili Andrea , Pasculli Lorenzo , Piermattei Viviana , Marcelli Marco , Zimmer Walter MX
Published: March 2020

Sound is the most widespread and pervasive kind of anthropogenic energy that human activities introduce into the marine environment. Sound energy input can be highly variable both in time and space, becoming an important part of the total ocean acoustic background. Moreover, the underwater sound plays an ecologically important role in marine ecosystems, being a critical sensory modality for many marine organisms that can be useful for both sensing the environment and communication. With the Marine Strategy Framework Directive (MSFD) (2008/56/EC, EU 2008), underwater noise has been recognized as pollution and included in the qualitative high-level descriptors to achieve good environmental status, GES.

During recent years, passive acoustic monitoring in the ocean has become a standard technique across the oceanographic community and is used to address biological, geological and meteorological issues. Due to the highly spatio-temporal variability of the ocean noise, a large number of the observing systems would be needed. Extended marine monitoring would require a reduction in the cost of platforms and instruments, without compromising data quality. Despite, a significant effort has been invested by the scientific community in the development of low-cost PAM recorders, much work still remains. Most of the problems are related to the pressure to which the devices are exposed, the battery pack limits, storage memory limits, and sensibility of the sound sensor once waterproofing and so on.

Here, we present a low-cost underwater sound recorder for coastal applications developed to be applied in both background noise monitoring and bioacoustic monitoring. This recorder consists of a high-performance USB-based microcontroller development system with an audio adapter that guarantees high audio quality. Additionally, test were conducted using both an ECM (Electret Condenser Microphone) and a MEMS microphone (Micro-Electro-Mechanical System) for a wide frequency range recordings to find the better solutions for good data quality. Compact and small in size, it can be easily installed on various oceanographic platforms for different types of sampling.

Here we present the first results of the laboratory and field tests, comparing our assembled device with a commercial recorder and a pre-calibrated hydrophone.  
Dormant and Active Landslides Classification Using Machine Learning Algorithms Coupled With Geological Field Inspection: Pohang Case Study
Authors: Althuwaynee Omar F. , Hwang In-Tak , Park Hyuck-jin , Kim Swang-Wan , Aydda Ali
Published: March 2020

In 1998, intense rainfall events hit the Pohang state, south west of Korea, which results in highest number of landslides registered in this area (generally the area has a relatively short history of landslide inventorying). The current inventory was digitized using Aerial photographs (lack of photogeological stereoscopic analysis of the aerial images) and coupled with basic field verification (due to limit funding available). Leaving the applied susceptibility maps models performed, using this inventory, with high degree of uncertainty.  Currently a research initiative carried to audit the landslide inventory using freely available aerial photographs and the time tuning function in Google earth for aerial archives. We notice some slopes area covered with deformed forest types that is similar in texture to that seen in digitized locations of landslides inventory. Due to long retune period of similar rainfall event, and with an assumption that the available landslides inventory might not complete. A certain hypothesis of additional investigation including field work to audit the landslides incidents is highly needed. In the current research, we assumed that, some dormant slopes caused by the 1998 event can be reactivated with the current extreme (uncontrolled) uses of slopes by human activities (constructions of real estate’s projects). To that end, a methodology of three main stages were proposed.

Stage one; Dormant susceptibility map (DSM) coupled with landslide susceptibility map will be produced. Machine learning supervised classification of eXtreme Gradient Boosting algorithms and Ensemble Random Forest, that run on tree-based classification assumption considering only active and dormant landslides as well as stable ground. Stage two; field work needs to be designed by geological and geotechnical experts to collect the doubtful locations by guidance of DSM and consider the new locations as dormant inventory. However, the areas of low dormant susceptibility (or mutual zones with Landslide susceptibility) will be recommended for advanced filed work and soil sampling test to complete the landslides identification of such highly urbanized area. Stage three; knowing the contour depths of diluvial and alluvial deposits can be useful for extracting areas that are more prone to landslides. Especially in the case of a rigid bedrock beneath the diluvial crust. Therefore, reconstructing the Quaternary formation thickness using boreholes repository and then represent the entire study area using CoKriging surface interpolation technique with elevation model. The current research results will provide us a better understanding of landcover stability conditions and their spatial prediction features.

 

hjpark@sejong.edu

omar.faisel@gmail.com
Observations and results from the High-Energy Particle Detector (HEPD) on-board CSES-01 satellite
Authors: Martucci Matteo ,   CSES-Limadou Collaboration
Published: March 2020

The China Seismo-Electromagnetic Satellite (CSES-01) is a mission developed by

the Chinese National Space Administration (CNSA) together with the Italian Space Agency (ASI), to investigate the near-Earth electromagnetic, plasma and particle environment. In addition, it has been designed to detect a wide number of disturbances of the ionosphere/magnetosphere transition region.

One of the main instruments on-board CSES-01 is the High Energy Particle Detector (HEPD); it is an advanced detector, completely designed and built in Italy, based on a tower of 16 scintillators and a silicon tracker that provides good energy resolution and a wide angular acceptance for electrons/positrons (3–100 MeV), protons (30–200 MeV) and light nuclei up to Oxygen.

The very good capabilities in particle detection and separation make the detector extremely well suited for Space Weather purposes;  being also able to continuously monitor the magnetospheric environment with high stability in time, HEPD can detect small variations related to transient phenomena taking place on the Sun and propagating through the solar wind.
After two years of data-taking, HEPD showed impressive capabilities in measuring the various particle distributions along its orbit, starting from sub-cutoff protons/electrons, up to galactic cosmic ray particles at higher latitudes. The former class includes both stably-trapped particles in the Radiation Belts and particles bounced back from the top of the atmosphere without being able to escape the magnetic trap (re-entrant albedo). For cosmic ray particles, precise measurements of their spectra are needed to understand the acceleration and subsequent propagation of low-energy particles in the inner sector of the heliosphere and, more general, in our Galaxy.

We report precision measurements of the protons in the >30 MeV energy region and electrons in the >5 MeV energy range, performed by HEPD in a un-disturbed heliosphere during a low solar activity period (2018/2020).
Integration of geophysical methods and fractures study for the Vallès geothermal system characterization (NE Spain)
Authors: Mitjanas Gemma , Ledo Juanjo , Queralt Pilar , Alías Gemma , Piña Perla , Marcuello Alex , Martí Anna
Published: March 2020

The Vallès geothermal system is located in the Catalan Coastal Ranges (CCR) (NE Spain). The CCR are formed by horst and graben structures limited by NE-SW and ENE-WSW striking normal faults, developed during the opening of the Valencia Trough (northwestern Mediterranean) (Gaspar-Escribano et al., 2004). In the Vallès Basin area, the thermal anomaly is located in the northeastern horst-graben limit, where a highly fractured Hercynian granodiorite is in contact with Miocene rocks by a major normal fault. This main structure seems to control the heat and the hot-water flow, nevertheless, the geological structure of this area, as well as the role of the Vallès normal fault, is poorly understood.

Magnetotellurics and gravity methods together with a detailed geological map have been applied in this area to understand the main structure. Although the geophysical part makes up most of the study, we are also elaborating a detailed geological map of the area, making a fractures study at different scales. We are working with DEM alignments analysis, and fractures study from outcrops and thin sections.

Our preliminary results in gravity show a strong gravity gradient in the NE-SW Vallès half-graben system and the recent MT profiles image the main fault of that system (Vallès normal fault). These results show a basin geometry with the major thickness of the basin towards the depocenter, disagreeing with the roll-over geometry assumed in previous works.

Interpretations of the fractures study, together with geophysical data and models, have allowed a preliminary characterization of damage zones associated with the fault system, which are directly related to the fluid flow and the hot springs. The nature of this damage zones could be related to relay ramps, commonly regarded as efficient conduits for fluid flow (Fossen and Rotevatn, 2016).
Afterslip and slow slip events in the postseismic deformation of the 2016 Pedernales earthquake, Ecuador
Authors: Rolandone Frederique , nocquet Jean-Mathieu , Mothes Patricia , Jarrin Paul , Vergnolle Mathilde
Published: March 2020

In subduction zones, slip along the plate interface occurs in various modes including earthquakes, steady slip, and transient accelerated aseismic slip during either Slow Slip Events (SSE) or afterslip. We analyze continuous GPS measurements along the central Ecuador subduction segment to illuminate how the different slip modes are organized in space and time in the zone of the 2016 Mw 7.8 Pedernales earthquake. The early post-seismic period (1 month after the earthquake) shows large and rapid afterslip developing at discrete areas of the megathrust and a slow slip event remotely triggered (∼100 km) south of the rupture of the Pedernales earthquake. We find that areas of large and rapid early afterslip correlate with areas of the subduction interface that had hosted SSEs in years prior to the 2016 earthquake. Areas along the Ecuadorian margin hosting regular SSEs and large afterslip had a dominant aseismic slip mode that persisted throughout the earthquake cycle during several years and decades: they regularly experienced SSEs during the interseismic phase, they did not rupture during the 2016 Pedernales earthquake, they had large aseismic slip after it. Four years after the Pedernales earthquake, postseismic deformation is still on-going. Afterslip and SSEs are both involved in the postseimsic deformation. Two large aftershocks (Mw 6.7 & 6.8) occurred after the first month of postseismic deformation in May 18, and later in July 7 2016 two other large aftershocks (Mw 5.9 & 6.3) occurred, all were located north east of the rupture. They may have triggered their own postseismic deformation. Several seismic swarms were identified south and north of the rupture area by a dense network of seismic stations installed during one year after the Pedernales earthquakes, suggesting the occurrence of SSEs. Geodetically, several SSEs were detected during the postseismic deformation either in areas where no SSEs were detected previously, or in areas where regular seismic swarms and repeating earthquakes were identified. The SSEs may have been triggered by the stress increment due to aftershocks or due to afterslip.
One stomatal model to rule them all? Evaluating competing hypotheses to regulate the exchange of carbon and water against experimental data
Authors: Sabot Manon , De Kauwe Martin , Medlyn Belinda , Pitman Andy
Published: March 2020

Nearly 2/3 of the annual global evapotranspiration (ET) over land arises from the vegetation. Yet, coupled-climate models only attribute between 22% – 58% of the annual terrestrial ET to plants. In coupled-climate models, the exchange of carbon and water between the terrestrial biosphere and the atmosphere is simulated by land-surface models (LSMs). Within those LSMs, stomatal conductance (gs) models allow plants to regulate their transpiration and carbon uptake, but most are empirically linked to climate, soil moisture availabilty, and CO2. Therefore, how and which gs schemes are implemented within LSMs is a key source of model uncertainty. This uncertainty has led to considerable investment in theory development in the recent years; multiple alternative hypotheses of optimal leaf-level regulation of gas exchange have been proposed as solutions to reduce existing model biases. However, a systematic inter-model evaluation is lacking (i.e. inter-model comparison within a single framework is needed to understand how different mechanistic assumptions across these new gs models affect plant behaviour). Here, we asked how, and under what conditions, nine novel optimal gs models differ from one another. The models were trained to match under average conditions before being subjected to: (i) a dry-down, (ii) high vapour pressure deficit, and (iii) elevated CO2. These experiments allowed us to identify the models’ specific responses and sensitivities. To further assess whether the models’ responses were realistic, we tested them against photosynthetic and hydraulic field data measured along mesic-xeric gradients in Europe and Australia. Finally, we evaluated model performance versus model complexity and the amount of information taken in by each model, which enables us to make recommendations regarding the use of stomatal conductance schemes in global climate models.
The Münsterdorf sinkhole cluster: Void origin and mechanical failure
Authors: Kaufmann Georg , Romanov Douchko , Werban Ulrike , Vienken Thomas
Published: March 2020

We describe and explore a group of collapse sinkholes located on a
sports field in the village of Münsterdorf close to Hamburg in northern Germany.
The collapse sinkholes develop since 2004 with a rate of one per year, with
sizes between 2-3 m in diameter and 3-5 meter depth, and are aligned to
a narrow east-west trending region..
In 20 m depth, cretaceous chalk is present in the area, topped by peri-glacial
and glacial deposits.
We summarize hydrological, geodetical, and geophysical data collected
and then discuss mechanical concepts for the occurence of the collapse sinkholes,
starting with simple analytical solutions and then expanding to distinct-element modelling.
We conclude that dewatering of the area might be an important aspect for the collapse sinkhole
developement.
Orogenic plateau margin and the coexistence of HP and HT metamorphic rocks
Authors: Teyssier Christian , Whitney Donna L , Rey Patrice F , Roger Françoise
Published: March 2020

Mature orogenic plateaux grow in response to the lateral redistribution of plateau material, driven by gravitational potential energy, from the thick plateau crust toward the thinner foreland crust. Folding and thrusting in the shallow crust as well as flow of weak deep crust toward the foreland result in plateau growth. The balance between plateau growth processes, including gravitational collapse of the orogenic crust, and the resistance to plateau propagation controls the position of plateau margins. Toward the end of orogenic plateau development, plateau margins are the loci of steep topographic gradients, where erosional processes can be aggressive. The margins also represent the transition between thick crust and thin/weak lithosphere beneath the plateau, and thinner crust and strong/thick lithosphere below the foreland.

The juxtaposition of thick and thin lithosphere favors strain localization along plateau margins, where thick lithosphere may partially subduct, or where strike-slip systems, such as the Altyn Tagh region of northern Tibet, develop. In either case, it is likely that the deep, flowing, partially molten crust will sample and entrain high-P (HP) metamorphic rocks such as granulite and eclogite. In the case of lithospheric strike-slip systems, crustal thickening in transpressional domains may lead to HP metamorphism, and crustal thinning in transtensional domains may lead to rapid exhumation of the deep crust, particularly where pull-apart structures in the shallow-crust allow the upward flow and emplacement of migmatite domes. For example, the Montagne Noire dome (French Massif Central) formed at the southern margin of the Variscan orogen in the late Carboniferous (315-295 Ma). This dome is filled with Variscan migmatite containing eclogite fragments that were sampled near Moho depths and entrained in the flowing partially molten crust; eclogitization and early crystallization of melt were coeval. In this example, the redistribution of mass and heat across the plateau margin, including the exhumation of near-Moho rocks, stabilized the crust and marked the end of orogeny.
Impact of emission reduction on aerosol-radiation interaction during heavy pollution periods over Beijing-Tianjin-Hebei region in China
Authors: Guo Chunwei , Wen Wei
Published: March 2020

In December 2015, the Beijing-Tianjin-Hebei (BTH) region in China experienced several episodes of heavy air pollution. The government issued emergency control measures immediately to reduce the pollution, which provided a good opportunity to explore impact of emission reduction on aerosol-radiation interaction. In this study, four tests were conducted, including the BASE1 simulation with emission reduction and aerosol-radiation interaction on, BASE2 simulation with emission reduction and aerosol-radiation interaction off, SEN1 simulation without emission reduction and aerosol-radiation interaction on and SEN2 simulation without emission reduction and aerosol-radiation interaction off. Results show that the aerosol-radiation interaction reduced downward shortwave radiation, temperature at 2 m and boundary layer height in region, but increased the relative humidity at 2 m, which were favorable for pollution accumulation. The interaction effect due to emission reductions increased downward shortwave radiation by 0~5 W/m2 on average, leading to a weak decrease of surface temperature by 0~0.05 °C, a weak decrease of the daytime boundary layer height by 0~8 m, and a weak increase of daytime mean relative humidity at 2m by 0.5%. If there were with aerosol-radiation interaction, it would enhance the effectiveness of emission control measures on air pollution control. The enhancement of PM2.5, PM10, and NO2 emission reduction effects reaches by 7.62%, 6.90%, 11.62% over region, respectively.
Vertical Gravity Gradient Modeling by 3-D Least Squares Collocation and its impact on quasigeoid-geoid separation term
Authors: Ahi Gonca , Akdoğan Yunus Aytaç , Yıldız Hasan
Published: March 2020

For the quasi-geoid determination by 3-D Least Squares Collocation (LSC) in the context of Molodensky’s approach, there is no need to measured or modelled vertical gravity gradient (VGG) as the 3-D LSC takes the varying heights of the gravity observation points into account. However, the use of measured or modelled VGG instead of the thereotical value is expected to improve the quasigeoid-geoid separation term particularly in mountainous areas. The VGG measurements are found to be different from the theoretical value in the range of - % 25 and + % 39 in western Turkey. Previously there has been no study using modelled VGGs for gravimetric geoid modelling in Turkey. VGGs are modelled by 3-D Least Squares Collocation (LSC) in remove-restore approach and validated by terrestrial VGG measurements in western Turkey. The effect of using modelled VGG instead of the theoretical one in quasigeoid-to-geoid separation term is found to be significant. The quasi-geoid computed by 3-D LSC in western Turkey is converted to geoids using theoretical or modelled VGG values and compared with GPS/levelling geoid-undulations.

 
Study on Assessment Method of Earthquake Casualties Based on Spatial Reasoning of Similarly Historical Cases
Authors: Zeng Tingting , Gong Adu , Chen Yanling
Published: March 2020

 Earthquake is one of the most serious natural disasters for human survival. Once a destructive earthquake occurs, it often leads to huge losses. However, in the early days after the earthquake, it was difficult to quickly obtain disaster information due to the interruption of traffic, electricity, and communications. Therefore, damage assessment based on similarly historical cases rapidly in access to limited disaster data situation is effective support for analysis disaster and making disaster relief decision. In this study, earthquake disaster statistics with a magnitude of 4.0 or above and casualties in China from 2000 to 2013 were selected as historical cases. The number of earthquake casualties was used as an evaluation index, and the earthquake magnitude, focal depth and time of earthquake are selected as disaster indicators. A similarity assessment model based on Manhattan distance was used to evaluate the similarity of historical cases, and the collection of historical cases that participated in the assessment were screened.And then considering the spatial correlation between historical cases and current disasters, an earthquake disaster assessment model based on spatial reasoning of similarly historical cases would be established. Then the Yushu earthquake in Qinghai in 2010, the Lushan earthquake in Sichuan in 2013, and the Ludian earthquake in Yunnan in 2014 were selected as cases for accuracy verification by comparing the actual number of casualties. The result shows that: (1) For the three verification cases, the best evaluation accuracy of the  model is above 95%, indicating that the method has certain feasibility and applicability in the assessment of earthquake casualties;(2) The accuracy of the disaster assessment is related to the number of participating cases. When there are more than two participating cases, the accuracy of the model assessment decreases steadily with the increase in the number of participating cases. When the number of participating cases is 3 ~ 4, the evaluation accuracy of the model is the best. The method of this study is low cost, high efficiency, timeliness strong, simple, less constraints and easy to implement. It has certain practical value and promotion prospects in disaster assessment.
Upper crustal structure at the KTB drilling site from ambient noise tomography
Authors: Qorbani Ehsan , Bianchi Irene , Kolínský Petr , Zigone Dimitri , Bokelmann Götz
Published: March 2020

In this study, we show results from ambient noise tomography at the KTB drilling site, Germany. The Continental Deep Drilling Project, or ‘Kontinentales Tiefbohrprogramm der Bundesrepublik Deutschland’ (KTB) is at the northwestern edge of the Bohemian Massif and is located on the Variscan belt of Europe. During the KTB project crustal rocks have been drilled down to 9 km depth and several active seismic studies have been performed in the surrounding. The KTB area therefore presents an ideal test area for testing and verifying the potential resolution of passive seismic techniques. The aim of this study is to present a new shear-wave velocity model of the area while comparing the results to the previous velocity models and hints for anisotropy depicted by former passive and active seismological studies. We use a unique data set composed of two years of continuous data recorded at nine 3-component temporary stations installed from July 2012 to July 2014 located on top and vicinity of the drilling site. Moreover, we included a number of permanent stations in the region in order to improve the path coverage and density. Cross correlations of ambient noise are computed between the station pairs using all possible combination of three-component data. Dispersion curves of surface waves are extracted and are then inverted to obtain group velocity maps. We present here a new velocity model of the upper crust of the area, which shows velocity variations at short scales that correlate well with geology in the region.