bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessing the RST_VOLC algorithm implementation on infrared Sentinel 3 SLSTR data
Authors: Falconieri Alfredo , Marchese Francesco , Mazzeo Giuseppe , Pergola Nicola , Tramutoli Valerio
Published: March 2020

RSTVOLC is a multi-temporal algorithm developed for detecting volcanic hotspots that was successfully used to monitor active volcanoes located in different geographic areas exploiting both polar and geostationary satellite data. The algorithm runs operationally at the Institute of Methodologies for Environmental Analysis (IMAA) to monitor Italian volcanoes in near-real time by means of Advanced Very-High-Resolution Radiometer (AVHRR) and Moderate Resolution Imaging Spectroradiometer (MODIS) data. In this study, we assess the possible RSTVOLC implementation on data from the Sea and Land Surface Temperature Radiometer (SLSTR). The latter is a new generation sensor flying onboard the ESA (European Space Agency) Sentinel-3 mission, offering some spectral channels in the infrared bands particularly suited to identify high temperature surfaces such as lava flows. Here, we verify the RSTVOLC implementation on SLSTR data despite the absence of a multiannual time series of satellite records, by using synthetic spectral reference fields. Results achieved by investigating recent eruptions of Mt. Etna and Stromboli (Italy) volcanoes are presented and discussed.
A composite method for past events characterisation providing insights in past, present and future coastal flood hazards: Joining historical, statistical and modeling approaches
Authors: Idier Deborah , Rohmer Jeremy , Pedreros Rodrigo , Le Roy Sylvestre , Lambert Jerome , Louisor Jessie , Le Cozannet Gonéri , Le Cornec Erwan
Published: March 2020

The characterisation of past coastal flood events is crucial for risk prevention. However, it is limited by the partial character of historical information on flood events and the lack or limited quality of past hydro-meteorological data. In addition coastal flood processes are complex, driven by many hydro-meteorological processes, making mechanisms and probability analysis challenging. These issues are tackled by joining historical, statistical and modelling approaches. We focus on a macrotidal site (Gâvres, France) subject to overtopping and investigate the 1900-2010 period. A continuous hydro-meteorological database is built and a damage event database is set up based on archives, newspapers, maps and aerial photographies. Using together historic information, hindcasts and hydrodynamic models, we identified 9 flood events, among which 5 significant flood events (4 with high confidence: 1924, 1978, 2001, 2008; 1 with a lower confidence: 1904). These flood events are driven by the combination of sea-level rise, tide, atmospheric surge, offshore wave conditions and local wind. The critical conditions leading to flood are further analysed, including the effect of coastal defences, showing that the present coastal defences would not have allowed to face the hydro-meteorological conditions of 09/02/1924 for instance, whose bi-variate return periods of exceedance Tr (still water level relative to the mean sea level and significant wave height) is larger than 1000 y. In addition, Tr is expected to significantly decrease with the sea-level rise, reaching values smaller than 1 y, for 8 of the 9 historical events, for a sea-level rise of 0.63 m, which is equal to the median amount of sea-level rise projected by the 5th Assessment Report of the IPCC in this region for RCP8.5 in 2100.
Assessments of Magnetic Reconnection and Kelvin-Helmholtz Instability at Ganymede's Upstream Magnetopause
Authors: Kaweeyanun Nawapat , Masters Adam , Jia Xianzhe
Published: March 2020

Ganymede is the largest moon of Jupiter and the only Solar System moon known to generate a permanent magnetic field. Motions of Jupiter’s magnetospheric plasma around Ganymede create an upstream magnetopause, where energy flows are thought to be driven by magnetic reconnection and/or Kelvin-Helmholtz Instability (KHI). Previous numerical simulations of Ganymede indicate evidence for transient reconnection events and KHI wave structures, but the natures of both processes remain poorly understood. Here we present an analytical model of steady-state conditions at Ganymede’s magnetopause, from which we conduct first assessments of reconnection and KHI onset criteria at the boundary. We find that reconnection may occur wherever Ganymede’s closed magnetic field encounters Jupiter’s ambient magnetic field, regardless of variations in magnetopause conditions. Unrestricted reconnection onset highlights possibilities for multiple X-lines or widespread transient reconnection at Ganymede. The reconnection rate is controlled by the ambient Jovian field orientation and hence driven by Jupiter’s rotation. We also determine Ganymede’s magnetopause conditions to be favorable for KHI wave growths in two confined regions each along a magnetopause flank, both of which grow in area whenever Ganymede moves toward Jupiter’s magnetospheric current sheet. KHI growth rates are calculated with the Finite Larmor Radius (FLR) effects incorporated and found to be asymmetric favoring the magnetopause flank closest to Jupiter. The significance of KHI wave growth on energy flows at Ganymede’s magnetopause remains to be investigated. Future progress on both topics is highly relevant for the upcoming JUpiter ICy moon Explorer (JUICE) mission.
Silent VLPs At Stromboli: Implications For Slug Vs. Plug
Authors: McKee Kathleen , Roman Diana , Fee David , Waite Gregory , Ripepe Maurizio
Published: March 2020

Very long period (VLP) seismic signals observed in volcanic environments are thought to be produced by magma and gas flow through conduits. Stromboli Volcano, Italy, typically produces hundreds of VLPs per day. These have been generally attributed to the flow of gas slugs through the shallow plumbing system and thus linked to the mechanism thought to drive Strombolian explosions. During a 6-day-long seismo-acoustic campaign in May 2018 (a period characterized by relatively low activity) we recorded 1900+ seismic events, the majority of which have significant energy in the VLP (2-100 s) band. We used a coincident STA/LTA trigger to identify seismic events in continuous waveform data and then used the PeakMatch algorithm (Rodgers et al., 2015) to identify seismic multiplets, with a focus on VLPs. To identify explosions, we applied the same coincident trigger to infrasound data, and manually identified gas jetting events using spectrograms and high-pass-filtered (20 Hz) waveforms. 

 

We identified ~250 explosions and ~600 jetting events. Seismic multiplet analysis identified two main families of repeating events. Family 1 (F1) has over 500 events and Family 2 (F2) has over 150 events based on a 0.7 correlation threshold. We find that F1 VLPs coincide in time with ~6% of explosions and ~0.8% of jetting events and F2 VLPs coincide in time with ~28% of explosions and ~2.7% of jetting events (we term these “silent VLPs”). These VLPs do not correspond with lava effusion (Marchetti and Ripepe, 2005; Ripepe et al., 2015). F2 have a higher dominant period (8-10 s) compared to F1 (3-4 s). The repeating VLPs are part of a broadband signal and the higher frequencies start after the VLP. VLP peak amplitudes are generally larger for F1 events. The dip of the VLP particle motion roughly locates the F1 and F2 VLP source centroids beneath the active crater and are stable throughout the dataset. Both VLP displacements show a small outward, large inward, and subsequent large outward motion from the crater. The lack of explosions relative to repeating VLPs does not support the slug model, where a slug rises through a conduit, generates a VLP through interactions with changes in conduit geometry, and then bursts at the lava free surface. Our observations support the plug model (Suckale et al., 2016). We suggest the “silent” VLPs are generated when the gas bubbles interact with and move into the semipermeable plug. Then the plug behaves as a mechanical filter for gas escape and allows for passive and explosive escape mechanisms.
Role of the creeping segment in the synchronization of earthquake cycles on oceanic transform faults revealed by numerical simulations in the framework of rate-and-state friction
Authors: Wei Meng , Shi Pengcheng
Published: March 2020

Synchronization behavior of large earthquakes, rupture of nearby faults close in time for many cycles, has been reported in many fault systems. The general idea is that the faults in the system have similar repeating interval and are positively coupled through stress interaction. However, many details of such synchronization remain unknown. Here, we built numerical models in the framework of rate-and-state friction to simulate earthquake cycles on the west Gofar fault, an oceanic transform fault in the East Pacific Rise. Our model is consisted of two seismic segments, separated by a creeping segment, for which the size and location is constrained by seismic data. The parameters in the seismic segments were set to reproduce M6 earthquakes every 5 years, to be consistent with observation. We varied the parameters in the creeping segment to understand its role on earthquake synchronization. We found that the width and the strength of the creeping segment will determine the synchronization of earthquake cycles on the two seismic segments. When the creeping segment is relatively narrow or weak, the system will become synchronized quickly and the synchronization remains for many cycles. When it is relatively wide or strong, the earthquake cycles on the two segments are not related but could be synchronized by chance. In both cases, earthquakes tend to rupture the entire seismic segment. Between these two end-member situations, the system fluctuated between synchronization and non-synchronization on the time scale of 5-10 cycles. The switch always happens when the partial rupture of the seismic segment occurs, resulting in moderate size earthquakes (M4-5) and earthquake cycle shift, which is likely caused by stress interaction through the creeping segment. Here, we conclude that the co-seismic slip and aseismic after slip in the creeping segment could promote the synchronization of earthquake cycles on oceanic transform faults, and likely in other tectonic systems. In addition, the average seismic ratio of the entire fault can be quite low, ranging between 0.2-0.4 because of the barrier segment. We suggest that the existence of creep segments contributed significantly to the well-observed low seismic ratio on oceanic transform faults.
Plate tectonic chain reaction constrained from noise in the Cretaceous Quiet Zone
Authors: Gürer Derya , Granot Roi , van Hinsbergen Douwe J.J.
Published: March 2020

The relative motions of the tectonic plates show remarkable variation throughout Earth’s history. Major changes in relative motion between the tectonic plates are traditionally viewed as spatially and temporally isolated events linked to forces acting on plate boundaries (i.e., formation of same-dip double subduction zones, changes in the strength of the boundary), or thought to be associated with mantle dynamics. A Cretaceous global plate reorganization event has been postulated to have affected all major plates. The Cretaceous ‘swing’ in Africa-Eurasia relative plate motion provides an ideal test-bed for assessing the temporal and spatial evolution of both relative plate motions and surrounding geological markers. Here we show a novel plate kinematic model for the closure of the Tethys Ocean by implementing intra-Cretaceous Quiet Zone time markers and combine the results with the geological constraints found along the convergent plate boundary. Our results allow to assess the order, causes and consequences of geological events and unravel a chain of tectonic events that set off with the onset of horizontally-forced double subduction ~105 Myr ago, followed by a 40 Myr long period of acceleration of the Africa relative to Eurasia that peaked at 80 Myr ago (at rates four times as high as previously predicted). This acceleration, which was likely caused by the pull of two same-dip subduction zones was followed by a sharp decrease in plate velocity, when double subduction terminated with ophiolite obduction onto the African margin. These tectonic forces acted on the eastern half of the Africa-Eurasia plate boundary, which led to counterclockwise rotation of Africa and sparked new subduction zones in the western Mediterranean region. Our analysis identifies the Cretaceous double subduction episode between Africa and Eurasia as a link in the global plate tectonic chain reaction and provides a dynamic view on plate reorganizations.
Asian summer monsoon Chemical and Climate Impact Project (ACCLIP): Highlights of multi-model pre-mission study
Authors: Kinnison Doug , Liang Qing , Pan Laura , Newman Paul , Atlas Elliot , Toon Brian , Randel William , Bresch Jim , Chin Mian , Tilmes Simone , Hodzic Alma , Honomichl Shawn , Lait Leslie , Smith Ren , Case Parker , Saiz-Lopez Alfonso , Jones Luke , Barre Jerome , Flemming Johannes
Published: March 2020

This presentation reports the findings of a multi-model pre-mission study in preparation for an airborne field campaign to investigate the upper troposphere and lower stratosphere (UTLS) composition under the influence of the Asian summer monsoon (ASM). The NSF/NASA supported airborne study is planned for the western Pacific atmosphere during July-August 2020 using a base in Okinawa, Japan. The pre-mission study uses three chemistry-transport models (i.e., NASA GSFC GEOS5, NCAR WACCM, and ECMWF CAMS) to investigate transport patterns and gas and aerosol chemical composition in the campaign region UTLS during the 2019 ASM period. In addition, artificial surface tracers from the WRF model helped identify the locations and evolution of rapid convective uplifting from regional sources. The impact of one typhoon occurrence during this 2019 ASM period will be discussed. Together, the multi-model results support the hypotheses of the ACCLIP campaign which identifies the western Pacific as a significant pathway for reactive chemical pollutants and climate relevant emissions from the ASM to enter the global UTLS.
Mesoscale Analysis of Severe Downslope Windstorm Caused by Gap Jet in Tianshan Canyon
Authors: hao Tang
Published: March 2020

Severe downslope wind triggered by the interaction between the gap jet and the asymmetrical topography in the Tianshan canyon which caused severe disasters of trains rolloverin the Turpan Depression in Xinjiang on February 28, 2007. To understand the mechanism of downslopewindstorm between the interaction of large-scale circulation background，mesoscale system and complex topography in this extreme windstorm.We use a WRF model to simulated it.Base on the mesoscale diagnostic analysis to simulative results，We propose a mechanism for the windstorm : Under the pressure gradient between north-south sides of the Tianshan Mountain, the air parcel climbs windward slope and flowsinto the Tianshan Gorge and then forms gap jet due to effect of narrow，the jet generated gravity waves forced by the asymmetric terrain of the Tianshan Canyon, and produces a lee waves in the leeward, which transmits the energy of the gap jet to the ground，andSevere downslope windstorm formed finally. In this process, the turbulence formed by the wave breaking and the critical layer absorb the upper layer energy downward, which strengthens the energy of the gap jet,and the atmospheric stability stratification exacerbates the sinking movement, which sinks energy to the ground.
Development of a numerical ice-sheet model for simulation of summit migration and dating
Authors: Saito Fuyuki , Abe-Ouchi Ayako , Obase Takashi
Published: March 2020

Ice divides are important locations for deep drilling on ice-sheets.  Precise computation around a divide requires spatially very high resolution due to the characteristics of ice-flow around the divide.In addition, ice flow pattern is significantly different between an ice divide and the other areas: the flow around the divide requires more stress terms to compute than the other area.  Moreover, age computation around the summit is typical application of ice sheet models.  Performances of several numerical schemes, such as a higher-order upwind scheme or a semi-Lagrangian scheme, have been compared, however there are still some schemes not yet implemented and examined for this issue.

This study presents a recent development of Ice sheet model for Integrated Earth system Studies (IcIES) in particular, for improvement of dating scheme and inclusion of higher-order mechanics.
Numerical study on debris flow in step-pools channel using smoothed particle hydrodynamics method
Authors: Li Shuai , Chen Xiaoqing , Peng Chong , Chen Jiangang
Published: March 2020

Drainage channel with step-pool systems are widely used to control debris flow. However, the blocking of debris flow often gives rise to local damage at the steps and baffles. Hence, the estimation of impact force of debris flow is crucial for design step-pools channel. This paper presents a numerical study on the impact behavior of debris flows using SPH (Smoothed Particle Hydrodynamics) method. Some important parameters, such as the baffle shape (square, triangle, and trapezoid) and the densities of debris flows are considered to examine their influence on the impact force. The results show that the largest peak impact force is obtained at the second last baffle, rather than the first baffle. Moreover, the square baffle gives rise to the largest impact force whereas the triangle baffle bears the smallest one among the three baffles. Generally, the peak impact force increases with increasing the inflow density. However, a threshold density, beyond which the peak impact force will decrease, is suggested by the simulations. Based on the numerical results, an improved expression to predict the impact force considering the inclined angle of baffle is proposed.
Evaluation of the WRF/WRF-Hydro coupled system for hydrological modeling
Authors: Liu Yuchen , Liu Jia , Li Chuanzhe , Yu Fuliang , Wang Wei , Qiu Qingtai
Published: March 2020

    WRF-Hydro is not only a stand-alone hydrological modeling architecture but also a coupling component for integrating hydrological models with atmospheric models. Sensitivity tests are carried out in this study for the most important parameters influencing the streamflow generation of the WRF/WRF-Hydro coupled system by targeting at the semi-humid and semi-arid catchments in Northern China. The main objective of the study is the parameters controlling the total water volume and the shape of the hydrograph are refined on the basis of sensitivity tests and their effects on the generation of the streamflow are addressed with the intent to apply the modeling system for streamflow forecasting. Two major aspects are considered in the calibration process for testing the sensitivity of the WRF-Hydro model parameters. On the one hand, it is to consider the parameters controlling the total water volume, which include the runoff infiltration parameter (REFKDT), and the surface retention depth (RETDEPRT) controlled by a scaling parameter named RETDEPRTFAC. One the other hand, it is to look at the parameters controlling the shape of the hydrograph, which include the channel Manning roughness parameter (MannN), and the overland flow roughness parameter (OVROUGHRT) controlled by the scaling parameter OVROUGHRTFAC. Through the sensitivity tests of the parameters affecting the runoff, it is found that REFKDT and MannN are the most sensitive parameter especially with unsaturated soil conditions. The findings of this study is to explore the variation laws of the key parameters in semi-humid and semi-arid areas, and to provide a reference for calibration and application of the WRF/WRF-Hydro coupled system.
Microphysics of Antarctic precipitation in climate models : recent advances and challenges
Authors: Vignon Étienne , Gehring Josué , Alexander Simon P. , Sotiropoulou Georgia , Besic Nikola , Jullien Nicolas , Planat Noémie , Madeleine Jean-Baptiste , Gerber Franziska
Published: March 2020

The current assessment of the Antarctic surface mass balance mostly relies on reanalysis products or climate model simulations. The ability of models to reproduce the precipitation field at the regional and continental scales not only depends on the simulation of the atmospheric dynamics over the Southern Ocean and of the advection of moisture towards the ice sheet, but also on the representation of the microphysical processes that govern the formation and growth of ice crystals and snowflakes. This presentation reviews recent studies to stress the importance and challenges of evaluating the precipitation microphysics over Antarctica in climate models. It also discusses how recent observational campaigns including ground-based remote-sensing instruments can help pinpoint key processes that should be represented in models. We then present tangible examples of evaluation and improvement of microphysical schemes in the Polar WRF model thanks to radar and lidar observations acquired near Dumont d’Urville and Mawson stations on the Antarctic coast. Particular attention is devoted to three processes : i) the sublimation of snowfall within the katabatic layer that considerably reduces the amount of precipitation that actually reaches the surface ; ii) the snowflake aggregation responsible for rapid depletion of crystals within clouds ; iii) the generation of supercooled liquid water in frontal clouds that leads to crystal/snowflake riming. Such studies, albeit preliminary, could pave the way for further evaluations of clouds and precipitation in climate models in different Antarctic contexts, especially in the cold and pristine atmosphere of the Plateau.
Monitoring bed level dynamics in mangrove wetlands by Laster ranging technique
Authors: Hu Zhan , Zhou Juanling , Peng Yisheng
Published: March 2020

Climate change-related temperature increases and sea-level rises have a significant impact on coastal environment. The morphodynamic processes on tidal flats under this global change have been studied by many numerical and analytical models. Studies on morphodynamic processes requires accurate bed-level measurement data to reflect the complex intertidal morphodynamics. The newly-developed SED sensor (Surface Elevation Dynamics sensor) has been introduced to provide continuous long-term monitoring with relatively low cost of labor and acquisition. However, when in use, the instrument is inserted directly to the ground, inducing scour pits around measuring point. Thus, we introduce a new instrument which make use of laser ranging called LSED (Laster based Surface Elevation Dynamics) sensor. It could avoid touching the bed surface and obtain data with 1-millimeter vertical resolution. The developed sensors can be installed at both bare and vegetated tidal flats to monitoring short-term bed level changes under different settings. In light of this, we set up a group of Laser-SED sensors in National Mangroves Park in Hailing island, Yangjiang. Firstly, these new instruments were tested using data obtained from LSED sensors and traditional Sediment Erosion Bars. An excellent agreement in these measurement methods indicating that LSED sensors are reliable in bed-level measurements. The obtained LSED-sensor data was subsequently used to develop machine learning predictors, which revealed the main drivers of the accumulative and daily bed-level changes. We conclude that the LSED-sensors can further support machine learning applications to extract new knowledge on coastal biogeomorphic processes.
Orographic gravity waves in OH-airglow imaging systems
Authors: Wüst Sabine , Till Jonas , Sedlak René , Hannawald Patrick , Schmidt Carsten , Stanič Samo , Bittner Michael
Published: March 2020

Atmospheric dynamics is strongly influenced by waves on different scales. Airflow over mountains can lead to all kinds of atmospheric waves, planetary and gravity waves as well as infrasound. Under certain circumstances these waves can propagate through the atmosphere and lead to a re-distribution of energy.

In the case of gravity waves, a stably stratified atmosphere is a mandatory requirement for their generation and vertical propagation. Additionally, the vertical propagation depends on the horizontal wind field.

In the Alpine and pre-Alpine region, we currently operate five OH-airglow imaging systems, which allow the investigation of orographic gravity waves. Depending on tropo-, strato- and mesospheric wind and temperature, it is checked which wavelengths can propagate into the fields of view of our instruments. This is done for a whole year in order to take into account annual and semi-annual cycles in wind and temperature.

Concerning the generation of gravity waves, we put our focus on our OH-airglow imager (FAIM) deployed at Otlica (45.9°N, 13.9°E), Slovenia. Here, we also have additional measurements of an OH-airglow spectrometer (GRIPS). In case studies, we investigate whether strong wind events (Bora) lead to strong gravity waves activity or enhanced potential energy density.

This work received funding from the Bavarian State Ministry of the Environment and Consumer Protection.
Working environment: requirements and restrictions at Underground laboratories
Authors: Paat Andrus , Karu Veiko
Published: March 2020

The Underground laboratories (Uls) due to their unique conditions can be used in many ways - as machinery test site by industrial equipment providers, for scientific and technical equipment testing, as test site for various experiments for instance in particle and nuclear physics, for food production, for safety personnel trainings, for data storage purposes etc. In order to use underground spaces for various purposes, you have to know what underground working conditions are. Depending on location, depth, and other characteristics the working conditions and requirements in every underground facility are different.

We present an overview of the underground working environment in six different Uls. Named Uls locates in different EU countries and have different national regulations and requirements. We conducted a common standard of underground working environment what acts as the minimum level on which the working environment must meet. We mapped working environment conditions in such topics as ownership and regulation, air and water quality, safety and monitoring in ULs, lighting requirements, noise, vibration and radiation measurements, including risks and monitoring. The results are based on held questionnaire and data collection tour, which was carried out among six Uls.

Additionally, we will highlight the best practices and experiences that Uls have implemented in order to improve their working conditions. These best practices are usually more than the national laws and regulations have requested. The collected practices will help to set new higher standards of the working environment for the other Uls to aim at. The best practices are based on held questionnaire and data collection tour, which was carried out among in six Uls. By sharing the best practices among the Uls will lead to knowledge transfer and implementation of better working conditions where new practices can be applied.

The minimum working environment conditions and the best practices are part of the Baltic Sea Underground Innovation Network, BSUIN, project, which is funded by the Interreg Baltic Sea Region Programme
Fluid inclusion and thermobarometric study of interaction between mafic xenoliths and plagiogranites in the Lotta River Area, Lapland Granulite Belt
Authors: Butvina Valentina , Golunova Maria , Safonov Oleg
Published: March 2020

Thermobarometric data and fluid inclusions data of conditions of interaction between mafic granulite xenoliths and plagiogranites in the Lotta river area, Lapland Granulite Belt, confirm the conclusion that leucocratic garnet-bearing plagiogranites of the Lapland complex are associated with the anatexis of country khondalites during peak of metamorphism.

The formation of plagiogranitic magmas, probably, occurred at depths of about 25-30 km. As they ascended, they captured numerous xenoliths (Kozlov, Kozlova, 1998). The most remarkable of them are two-pyroxene-plagioclase granulite xenoliths (orthopyroxene ± clinopyroxene + plagioclase ± quartz + magnetite + ilmenite + pyrrhotite). The xenoliths show extensive amphibole formation, which is manifested as coronas of K-bearing pargasite-edenite amphibole and coarse-grained amphibole-quartz symplectites in contacts of pyroxenes, magnetite, ilmenite and pyrrhotite with plagioclase.

The more calcic composition of plagioclase and the lower Mg-number of pyroxenes in the amphibolized portions of xenoliths correspond to the amphibole formation via reaction: Opx + Ilm + Mt + Pl = Amph ± Qtz. Amphibole formation is locally accompanied by biotite, indicating the addition of potassium into the xenoliths.

A pressure of 6.0-6.4 kbar was estimated from the equilibrium of clinopyroxene + orthopyroxene + plagioclase + quartz in non-amphibolized portions of xenoliths. The corresponding temperatures 800-860°C are within the range of temperatures estimated for the plagiogranite crystallization (Kaulina et al., 2014) as well as peak temperatures of the M2 tectonic-thermal event in the Lapland complex (Mints et al., 2007). Amphibole-plagioclase equilibrium (Blundy, Holland, 1990) recorded the temperatures of the amphibole formation 740-780°C at a pressure of 5.0-5.5 kbar. Compositional variations of amphibole toward tremolite indicate further cooling. It was, probably, due to the interaction of an essentially aqueous fluid issued from plagiogranitic magma with xenoliths as they were captured and transported.

Indeed, xenoliths are crossed by plagiogranitic veins. Abundance of aqueous-salt (17-20 wt. % NaCl eq.) inclusions and the subordinate amount of carbon dioxide inclusions in plagiogranite minerals confirm this assumption. Thus, plagiogranites of the Lapland complex and associated fluids were formed inside the complex at P-T parameters comparable to the peak conditions of granulite metamorphism. During ascension, these granite magmas could only produce fluid effects on the country rocks including xenoliths.
Fingerprints from past charcoal burning - lessons learned and future perspective studying Relict Charcoal Hearths (RCH)
Authors: Raab Thomas , Raab Alexandra , Hirsch Florian , Bonhage Alexander , Schneider Anna
Published: March 2020

Digital Elevation Models (DEMs) recorded by LiDAR are now available for large areas, providing an opportunity to map small landforms for the first time in high resolution and over larger areas.  The majority of these small earth surface structures is of anthropogenic origin, and their formation is often ancient. The newly visible microrelief can therefore reflect the imprints of centuries or millennia of past land uses. Among the anthropogenic structures identified in the new high-resolution DEMs, Relict Charcoal Hearths (RCHs) are particularly widespread and abundant. RCHs are remains of past charcoal burning and mainly found in pre-industrial mining areas of Europe and North America. They normally have a relative height of fewer than 50 centimetres on flat terrain and a horizontal dimension ranging from about 5-30 metres. Despite the small spatial dimensions, RCHs can reach significant land coverage due to their enormous numbers. Recent LiDAR data show that a remarkable area of our landscape has this human fingerprint from the past. We therefore need to ask about its effect on soil landscapes and ecosystems in general. The growing relevance of RCHs is also noticeable in the rising number of RCH case studies that have been conducted. This study reviews the state of knowledge about RCHs mainly by addressing three coupled legacies of historic charcoal burning: the geomorphological, the pedological, and the ecological legacy. We are going to present recent findings on these three legacies.
Clustering and Connectivity of Fractal-Fracture Networks: Are they related?
Authors: Sahu Ajay Kumar , Roy Ankur
Published: March 2020

It well known that fracture networks display self-similarity in many cases and the connectivity and flow behavior of such networks are influenced by their respective fractal dimensions. One of the authors have previously implemented the concept of lacunarity, a parameter that quantifies spatial clustering, to demonstrate that a set of 7 nested natural fracture maps belonging to a single fractal system, but different visual appearances have different clustering attributes. Any scale-dependency in the clustering of fractures will also likely have significant implications for flow processes that depend upon fracture connectivity. It is therefore important to address the question as to whether the fractal dimension serves as a reasonable proxy  for the connectivity of a fractal-fracture network or is it the lacunarity parameter that may be used instead. The present study attempts to address this issue by studying the clustering behavior (lacunarity) and connectivity of fractal-fracture patterns. We compare the set of 7 nested fracture maps mentioned earlier which belong to a single fractal system, in terms of their lacunarity and connectivity values. The results indicate that while the maps that have the same fractal dimension have almost similar connectivity values, there exist subtle differences such that both the connectivity and clustering change systematically with the scale at which the networks are mapped. It is further noted that there appears to be an exact correlation between clustering and connectivity values. Therefore, it may be concluded that rather than fractal dimension, it is the lacunarity or scale-dependent clustering attribute that control connectivity in fracture networks.
Extension of the regional climate model REMO by a 5-layer soil scheme
Authors: Abel Daniel , Pollinger Felix , Ziegler Katrin , Paeth Heiko
Published: March 2020

The EFRE-Project BigData@Geo, founded by the European Union, aims to create highly resolved climate projections for the model region of Lower Franconia in Bavaria, Germany. These projections are analyzed and made available to local stakeholders of agriculture, forestry, and viniculture as well as the public. As recent regional climate models are not dealing with the necessary spatiotemporal resolution the model REMO will be developed in the project‘s frame in cooperation with the Climate Service Center Germany (GERICS).

For these very high resolutions, besides improvements like the non-hydrostatic atmosphere, higher resolved static land surface parameters, and land use land cover changes, etc., realistic modeling of the soil hydrology becomes absolutely necessary. Therefore, REMO is extended by a 5-layer soil scheme which is a first step to overcome restrictions of the recently used soil hydrology scheme due to the included vertical water flow. Furthermore, the current work also aims to implement lateral water flows between grid cells because this is the only way to model the soil hydrology appropriate to the project‘s question.

The current model version of REMO includes a bucket scheme that treats the soil hydrology as a single layer. The soil depth is equal to the rooting depth and, thus, depends on the overlying vegetation class. Consequently, the whole soil moisture of the soil is available for transpiration. Evaporation only occurs if the soil moisture reaches at least 90 % of the field capacity.

The 5-layer scheme has 5 layers with increasing thicknesses for deeper layers. The maximum depth of the soil is at approximately 10 m or the depth of the bedrock. Due to the existence of water below the rooting zone and the processes of capillary rise and percolation more water becomes available for transpiration compared to the bucket scheme. Furthermore, evaporation only occurs if the uppermost layer contains soil moisture which is a more realistic process representation as well.

First results of the comparison of the two schemes and with observation data in the EURO-CORDEX region and a german subregion are presented. We also show some sensitivity studies of the current improvements to the parameterizations of the 5-layer scheme which are necessary for the goal of incorporation of the lateral flow.
Shifting pattern of hook structures and impacts on storm runoff extremes under anthropogenic climate warming
Authors: Yin Jiabo , Guo Shenglian , Gu Lei
Published: March 2020

Understanding the hook structure between storm runoff extremes and temperature is key to quantifying the complex response of flooding regime to anthropogenic climate warming, but its underlying mechanisms, shifting trajectories and environmental consequences are highly uncertain. Our in-situ observations suggest a spatially homogeneous negative sensitivity of relative humidity to rising temperatures, with a colder peak point temperature (Tpp) than that of precipitation and storm runoff extremes, implying that atmospheric moisture constraint plays an important but inferior role than thermodynamic drivers in extreme-temperature scaling. To probe into the complex interplay of hook structures and weather-related hazard evolution, we focus on flooding menace over China’s main catchments and project streamflow scenarios with model cascade chains combining 31 CMIP5 models, bias correction and four hydrological models. The ensemble projections confirm a severe enhancement of extremes, with involvement of the hook structure’s continuous shift towards a warmer temperature accompanying by an upward movement under future warming.
Characteristics of natural radiation background at the Research and Education mine Reiche Zeche (Germany) performed within the BSUIN project.
Authors: Szkliniarz Katarzyna , Polaczek-Grelik Kinga , Walencik-Łata Agata , Kisiel Jan , Mueller Toni , Schreiter Falk , Hildebrandt Robert
Published: March 2020

The Reiche Zeche mine is one, out of 6 Underground Laboratories (ULs) participating in the BSUIN (Baltic Sea Underground Innovation Network) project. The main goal of BSUIN is to improve the utilisation of Underground laboratories operating in the Baltic Sea Region by creating an umbrella organisation, an association, to represent the underground locations. To improve the utilisation the Uls, the sites have been characterized to understand the possibilities of the sites. Of of the studied characteristics is natural background radiation. The Reiche Zeche mine is located at a depth of 150 m (410 m w.e.) in the eastern part of the Erzgebirge Mountains, Germany. The measurements of natural background radiation (NBR) were performed: (1) in-situ by using portable HPGe semiconductor spectrometer and RAD7 electronic radon detector, and (2) in the laboratory, where the concentration of radioisotopes in water and rock samples was determined. The laboratory measurements were done in the Institute of Physics, University of Silesia (Poland) by using a liquid scintillation α/β counter (LSC), gamma-ray spectrometry and α-particle spectrometry. The obtained results of natural radioactivity in Reiche Zeche (BSUIN UL) will be presented.
The status of Chandler wobble
Authors: Wang Guocheng , Liu Lintao , Liu Jinzhao , Tu Yi
Published: March 2020

The Chandler wobble (CW) and Annual wobble (AW) are the main components of the Earth’s Polar motion, which play an important role in our understanding of their excitations. The Fourier Basis Pursuit Band-Pass Filtering (FBPBPF) method, which can effectively suppress the edge effect, are applied to extract the CW and AW in Earth's polar motion during 1900-2016. Through analyze the variation of CW extracted by the FBPBPF method, we find that the amplitude of the CW has been diminishing since 1995. However, the amplitude of the CW had stopped decline in the last year, and start to increase at now.
Potential Effect of Halogens on Atmospheric Oxidation in China
Authors: Li Qinyi , Badia Alba , Wang Tao , Sarwar Golam , Fu Xiao , Zhang Li , Zhang Qiang , Fung Jimmy , Cuevas Carlos A. , Wang Shanshan , Zhou Bin , Saiz-Lopez Alfonso
Published: March 2020

Air pollution has been a hazard in China over recent decades threatening the health of half a billion people. Much effort has been devoted to mitigating air pollution in China leading to a tremendous reduction in primary pollutants emissions from 2013 to 2017, while a continuously worsening trend of surface ozone (O3, a secondary pollutant and greenhouse gas) was observed over the same period. Atmospheric oxidation, dominated by daytime reactions involving hydroxyl radicals (OH), is the critical process to convert freshly-emitted compounds into secondary pollutants, and is underestimated in current models of China’s air pollution. Halogens (chlorine, bromine, and iodine) are known to profoundly influence oxidation chemistry in the marine environment; however, their impact on atmospheric oxidation and air pollution in China is unknown. In the present study, we report for the first time that halogens substantially enhance the total atmospheric oxidation capacity in polluted areas of China, typically 10% to 20% (up to 87% in winter) and mainly by significantly increasing OH level. The enhanced oxidation along the coast is driven by oceanic emissions of bromine and iodine, and that over the inland areas by anthropogenic emission of chlorine. The extent and seasonality of halogen impact are largely explained by the dynamics of Asian monsoon, location and intensity of halogen emissions, and O3 formation regime. The omission of halogen emissions and chemistry may lead to significant errors in historical re-assessments and future projections of the evolution of atmospheric oxidation in polluted regions.
Revisiting the Global and Regional Steric Sea-level Trends in the Satellite Era
Authors: Camargo Carolina , Riva Riccardo , Hermans Tim , Slangen Aimée
Published: March 2020

The steric component of sea-level change comprises variations in the temperature (thermosteric) and salinity (halosteric) of the oceans, which alter the water’s density, leading to volumetric variations of the water column. Although its importance is unarguable, throughout the literature there is a disagreement on how much the steric component actually contributes to sea-level change.

Here, we investigate two sources of uncertainty to steric trends, both at global and regional scale. First, we look at how the use of different temperature and salinity datasets influences the estimated steric height. For that, we analyzed 15 datasets, combining different techniques (hydrographic profiles, Argo floats and ocean reanalyses). Second, since the estimation of uncertainties for linear and quadratic trends requires the adoption of a noise model, we compared the performance of several different noise models.  

We find that by varying both the dataset and noise-model, the global mean trend and uncertainty from 2005 to 2015 can vary from 0.566 to 2.334 mm/yr and 0.022 to 1.646 mm/yr, respectively. This range becomes even larger at regional scales. At a global scale, the selection of datasets has a larger influence on the trend, while at a regional scale the choice of the noise model dominates the spread in steric sea-level trends. Our results emphasize the need to use an ensemble of datasets to infer steric changes, and to carefully choose a noise model.
On Downward Continuing Airborne Gravity Data for Local Geoid Modeling
Authors: Li Xiaopeng , Huang Jianliang , Slobbe Cornelis , Klees Roland , Willberg Martin , Pail Roland
Published: March 2020

The topic of downward continuation (DWC) has been studied for many decades without very conclusive answers on how different methods compare with each other. On the other hand, there are vast amounts of airborne gravity data collected by the GRAV-D project at NGS NOAA of the United States and by many other groups around the world. These airborne gravity data are collected on flight lines where the height of the aircraft actually varies significantly, and this causes challenges for users of the data. A downward continued gravity grid either on the topography or on the geoid is still needed for many applications such as improving the resolution of a local geoid model. Four downward continuation methods, i.e., Residual Least Squares Collocation (RLSC), the Inverse Poisson Integral, Truncated Spherical Harmonic Analysis, and Radial Basis Functions (RBF), are tested on both simulated data sets and real GRAV-D airborne gravity data in a previous joint study between NGS NOAA and CGS NRCan. The study group is further expanded by adding the TU Delft group on RBF and the TUM group on RLSC to incorporate more updated knowledge in the theoretical background and more in-depth discussion on the numerical results. A formal study group will be established inside IAG for providing the best answers for downward continuing airborne gravity data for local gravity field improvement. In this presentation, we review and compare the four methods theoretically and numerically. Simulated and real airborne and terrestrial data are used for the numerical comparison over block MS05 of the GRAV-D project in Colorado, USA, where the 1cm geoid experiment was performed by 15 international teams. The conclusion drawn from this study will advance the use of GRAV-D data for the new North American-Pacific Geopotential Datum of 2022 (NAPGD2022).
Accumulation of soil carbon and nutrients along a 127-yr soil chronosequence in the Hailuogou Glacier retreat area
Authors: Sun Shouqin , Wang Genxu , Zhang Xinbao
Published: March 2020

Climate change is resulting in accelerated retreat of glaciers worldwide, leaving behind bare soil and succeeding vegetation at ecological sites that share similar attributes but represent different ages across chronosequences of primary succession. These glacial succession chronosequences provide a space for time exchange opportunity to investigate the development of soil and vegetation from the very beginning. In this study we investigated how soil carbon (C), nitrogen (N) and phosphorus (P) nutrients were accumulated along a 127-yr primary successional chronosequence on Hailuogou glacier, China, where the soil samples were collected at 1-cm depth interval from 9 sectioned profiles with ages ranged from 27 yr to 127 yr on the glacial retreated area. Soil organic C (SOC) and TN showed an increasing trend along the chronosequence. The organic C and N accumulation was minimal after 27 yr of succession; with succession the soil had slightly C and N accumulation at the surface 0-1 cm depth after 45 to 53 years, and had obvious accumulation at the 0-2 cm depth after 59-72 years; the SOC and N accumulation extended to the 0-5 cm depth after 87 yr and to the 0-10 cm depth after 102 yrs. In contrast soil total P exhibited a depleting trend along the succession. Results indicated that the C and N accumulation along a glacier retreat chronosequence is not linear, but a slow increase in accumulating rates in the first 72 years, followed by a sharp increase between 72 to 87 years and then slow down with succession proceeded.