bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of bedrock weathering in microaggregate formation - limestone alteration in the aeration zone
Authors: Aehnelt Michaela , Ritschel Thomas , Totsche Kai Uwe
Published: March 2020

During pedogenesis, the development of the soil aggregate system may be strongly dependent on weathering of bedrock in the vadose zone. There, periodic drying and flushing by meteoric waters provides alternating hydro- and biogeochemical conditions for fluid-rock interactions and provokes the dissolution, displacement and placement of minerals as well as the release or adsorption of colloids. As a result, the seepage suspension is enriched with mobile mineral and organic matter that infiltrates into the bedrock void system thereby fueling aggregate forming materials and composite building units to exposed surfaces of the bedrock. We aim to elucidate related bedrock alteration processes in dependence on water composition, seepage vs. saturation and the fracture network during weathering.

Our study combines the investigation of the weathering rim of natural bedrocks (outcrop analogue) with the simulation of the natural conditions by column experiments in the laboratory. Study object are Triassic limestones (Upper Muschelkalk) of the Hainich area in Thuringia (central Germany). The columns were filled with fresh, unaltered material, crushed into coarse gravel fraction size and percolated with artificial rainwater or soil litter extract over a runtime of 6 months. In order to mimic natural conditions percolation periods changed with periods of drying. Geochemical data of the liquid phase resemble very well the alternating periods of drying and flushing by systematic changes of the element concentration and milieu parameters. Generally, dissolved elements in the seepage are higher in concentration when litter extract is used pointing towards a significant impact on dissolution kinetics, especially after periods of longer water-rock interaction. Weathered natural bedrock surfaces (bedrock clasts in the covering soil and fractures and voids in the bedrock) exhibit carbonate dissolution (edge pits and dissolution vugs) and the formation of clay mineral coatings, in part with iron oxides. The same holds true for rock clasts after the column experiments. The alteration is macroscopically visible by brownish and beige coatings on formerly greyish pristine surfaces. This feature seems more pronounced on clasts percolated with liquids from soil litter extracts than on clasts treated with artificial rainwater indicating the formation of organo-mineral associations during solid-liquid interaction.

Generally in both, nature and experiment, facial aging features include the dissolution of carbonates, the formation of clay minerals as well as oxides and hydroxides of iron, but also the appearance of organic constituents. Our results contribute to a better mechanistic understanding of the role of bedrock alteration during weathering for (a) the provision of microaggregate forming materials and (b) the formation of composite building units and microaggregates from pristine environments.

 
A new snapshot interferometric imaging spectrometer: a first comparison with a classical grating spectrometer.
Authors: Dolet Aneline , Picone Daniele , Gousset Silvère , Dalla Mura Mauro , Le Coarer Etienne , Voisin Didier
Published: March 2020

Atmospheric gas monitoring is of major importance for climate change and air quality. Indeed, emissions regulations and control rely on the detection and quantification of the concentration of gases such as CO2, CH4, NO2, O3, etc. Good control on emissions is key to reduce those gases impacts on climate change and people’s health.

The accuracy and relevance of such measurements depend on higher spatial, spectral and temporal resolutions. To this end, conventional dispersive hyperspectral imaging systems are typically used. However, these sensors are submitted to compromises in terms of price, spectral and spatial resolutions and temporal acquisition frequency. To overcome these compromises, a new ground-breaking device is currently developed under the name Imaging Spectrometer on Chip (ImSPOC). It is based on an interferometric imaging system that allows real time acquisition with significant spatial and spectral resolutions. The device, which takes the volume of a matches’ box, could in the future be a building block for Nano-satellites, drone, or ground based measurements platforms. The particularity of this device is the snapshot acquisition of an interferometer by pixel of the imaged scene instead of a spectrum. This is obtained by using a matrix of Fabry-Perot interferometers with different thicknesses placed in front of a photodetector. ImSPOC is then of great interest for real-time acquisitions. However, the acquisition of interferometers requires signal processing developments to reconstruct the corresponding spectra. This reconstruction relies typically on the resolution of an inverse problem. Some models of the device have been proposed to this end.

To validate the efficiency of this new device and to test the developed algorithms, acquisitions were conducted tracking the sun during a whole day using our device and a conventional diffraction grating based spectrometer. In this way, the reconstructed spectra from our device can be compared to the classical spectrometer ones. Particularly, the absorption peaks are compared (their central wavelengths, amplitude, etc.). To go further, the gas characterization from both devices will be compared (gas detection, evolution over time of the vertical concentration profiles, etc.). These results allow the validation of our device to this application and highlight the signal processing improvements that could be done in the future to have more accurate measurements.
New records of freshwater ostracoda from the xingyun lake
Authors: Xie Manping
Published: March 2020

This present paper reports eight modern ostracode collected from the bottom of the Xingyun Lake,Yunnan Province, including Candonocypris novaezelandiae (Baird, 1843), mateless cyclocypris Cypridopsis Vidua (O.F.M ller, 1776), star (which really wedge dielectric) Eucypris CF. Cuneata (Tsao, 1959), Cleveland star kraeplini (G.W.M mediated Cypris ller, 1903) Belgium, sheshi (similar) glass dielectric Schellencandona CF. Belgica (Klie, 1937), Fabaeformiscandona subacuta (Yang, 1982), unarmed mobs mediated Cetacella inermis (Martin, 1958), the Yunnan flower (compare kinds) Yunnanicyhere cf.reticulate mediated gen.etsp.nov. the true star (dielectric wedge comparison of three) Eucypris CF. Cuneata (Tsao, 1959), unarmed mobs mediated Cetacella inermis (Martin, 1958) and Yunnan (a comparison of dielectric reticulate flowers) Yunnanicyhere cf.reticulate gen.etsp.nov.  these species are newly recorded from modern lakes.It has enriched the understanding of freshwater ostracoda of the biological communities in China.

Key word  freshwater ostracods; Xingyun Lake; Yunnan Province
Simulating the spatio-temporal variability in terrestrial - aquatic DOC transfers across Europe
Authors: Gommet Celine , Lauerwald Ronny , Ciais Philippe , Regnier Pierre
Published: March 2020

Inland waters receive important amounts of dissolved organic carbon (DOC) from surrounding soils, which drives an important net-heterotrophy and subsequent CO2 emission from these systems.  At the same time, this DOC transfer decreases the soil carbon sequestration capacity, which may limit the efficiency of the land carbon sink. The variation of DOC stocks and fluxes in time and space is modeled using the ORCHILEAK model that couples terrestrial ecosystem processes, carbon emissions from soils to headwater streams by runoff and drainage, as well as carbon decomposition and transport in rivers until export to the coastal ocean. The runs were performed at the resolution of 0.5°, taking advantage of the relatively dense observations of soil and river DOC available for European catchments.  The model was first evaluated for the hydrology by comparing the discharge at different stations along several large European rivers. The DOC measurements were used to calibrate the different parameters of the ORCHILEAK model and to evaluate the model results. ORCHILEAK was then used to generate the first European map of DOC stocks and leaching for the four seasons. We estimate a soil DOC stock at 71 TgC and a DOC leaching flux of 7,8 TgC/yr, largely dominated by runoff exports during the winter season. Our model results also allow to identify the underlying processes controlling the fraction of terrestrial NPP exported to the European inland water network. The next step will be to use the model to hindcast historical DOC fluxes and predict their evolution over the 21st century using climate change and land use projections from the SSP-RCP scenarios developed for the IPCC assessment report.
Weaker cooling by aerosols due to dust-pollution interactions
Authors: Klingmueller Klaus , Karydis Vlassis , Bacer Sara , Stenchikov Georgiy , Lelieveld Jos
Published: March 2020

The interactions between aeolian dust and anthropogenic air pollution, notably chemical ageing of mineral dust and coagulation of dust and pollution particles, modify the atmospheric aerosol burden. Since the aerosol particles can act as cloud condensation nuclei, this not only affects the radiative transfer directly via aerosol radiation interactions, but also indirectly through cloud adjustments. We study both radiative effects using the global ECHAM/MESSy atmospheric chemistry-climate model (EMAC) which combines the Modular Earth Submodel System (MESSy) with the European Centre/Hamburg (ECHAM) climate model. Our simulations show that the dust-pollution interactions reduce the cloud water and hence the reflection of solar radiation. The associated climate warming outweighs the cooling which the dust-pollution interactions exert through the direct radiative effect. In total, this results in a net warming by dust-pollution interactions which we estimate to moderate the negative global anthropogenic aerosol forcing at the top of the atmosphere by more than 0.1 W / m².
Inter-comparison of four operational satellite Fire Radiative Power (FRP) products: A spatial and temporal consistency assessment.
Authors: Mota Bernardo , Gobron Nadine , Wooster Martin
Published: March 2020

 We inter-compare four remotely sensed Fire Radiative Power (FRP) products, the polar-orbiter products derived from active fires detected using the Moderate Resolution Imaging Spectroradiometer data (MCD14ML) and VIIRS (VNP14ML and VNP14IMGML), and geostationary products derived from data collected by Meteosat’s Spinning Enhanced Visible and Infrared Imager (the LSA-SAF FRP-PIXEL product). We focus on seven years of data (January 2012 to December 2018), and using the ability of the geostationary product to capture the daily fire cycle we quantify for each polar-orbiter FRP product the proportion of daily fire energy release that they capture and that which they miss, and also identify the areas where their overpass times successfully capture the diurnal fire activity peak, and where they do not. In addition, by analysing frequency density (f-D) distributions of FRP at a 0.5° grid cell resolution we evaluate each products minimum FRP detection limit, which typically precludes detection of a proportion of the highly numerous but individually relatively small and/or low intensity fires. Results are summarized by biome type based on the ESA CCI Land Cover product. Our inter-comparison allows for the identification and quantification of some of the key non-fire effects causing FRP underestimation in satellite FRP products: pixel size, pixel area growth off-nadir, and the low temporal resolution of polar-orbiting sensors. Our results and the methodology developed herein should serve to evaluate and cross-calibrate FRP estimates obtained by the future Copernicus Climate Change Services (C3S) FRP products, which initially at least will be based only on SLSTR data collected by the Sentinel-3 satellite.
Advances in earthquake-swarms monitoring networks WEBNET and REYKJANET
Authors: Klicpera Jakub , Doubravová Jana , Horálek Josef
Published: March 2020

The IG CAS in cooperation with IRSM CAS operates two local seismic networks deployed to monitor the seismic swarms in West Bohemia/Vogtland, Czechia and Reykjanes Peninsula, Iceland. 

WEBNET monitors the region of West Bohemia since 1991 developing from 4 short period stations to 24 broadband stations today. The seismoactive region West Bohemia/Vogtland lies in the border area between Czechia and Germany in the western part of Bohemian Massif. It is an intra-continental area with persistent swarm-like seismicity but rarely also main-shock after-shock sequences may occur. 

REYKJANET local seismic network is situated in Reykjanes Peninsula on Southwest Iceland. The area is an onshore part of the mid-Atlantic plate boundary between the North America and Eurasia Plates. The seismic activity of Reykjanes peninsula is represented by typical main-shock after-shock sequences as well as earthquake swarms. The REYKJANET network was built in 2013 and it consists of 15 stations placed around the epicentral area.

Both networks have been substantially upgraded during the last years. In case of REYKJANET the replacement of old sensors and digitizers with new ones made the operation easier and ready for near future plan to stream the waveform files in real time. WEBNET network which was long years divided into two subnets – on-line permanent stations and off-line autonomous stations, was recently homogenized by eco-powering and 4G LTE data connecting of the off-line stations. Additonally, the micro network HORNET was deployed within the WEBNET epicentral zone to monitor Horka water dam.

Data from both above mentioned networks are automatically searched for seismic events by the neural-network-based detector designed by Doubravová et al. (2016, 2019) providing event list with completeness magnitude Mc=0 for REYKJANET and Mc=-0.5 for WEBNET. The main difference of sensitivity is given by different noise levels of the two networks.
Assessment of different indices from Landsat time series in burned area mapping
Authors: Liu Jinxiu
Published: March 2020

Fire is recognized as an important land surface disturbance, as it influences terrestrial carbon cycle, climate and biodiversity. Accurate and efficient mapping of burned area is beneficial for social and environmental applications. Remote sensing plays a key role in detecting burned areas and active fires from reginal to global scales. Due to the free access to the Landsat archive, studies using dense time series of Landsat imagery for burned area mapping are appearing and increasing. However, the performance of Landsat time series when using different indices for burned area mapping has not been assessed. In this study, the objective was to identify which indices can detect burned area better when using Landsat time series in savanna area of southern Burkina Faso. We selected Burned Area Index (BAI), Normalized Burned Ratio (NBR), Normalized Difference Vegetation Index (NDVI), Global Environmental Monitoring Index (GEMI) for comparison as they are commonly used indices for burned area detection. The algorithm was based on breakpoint identification and burned pixel detection using harmonic model fitting with different indices Landsat time series. It was tested in savanna area in southern Burkina Faso over 16 years with 281 Landsat images ranging from October 2000 to April 2016.The same reference data was used to evaluate the performance of burned area detection with different indices Landsat time series. The result demonstrated that BAI was the most accurate in burned area detection from Landsat time series, followed by NBR, GEMI and NDVI.
Revealing unknown subglacial carbon processes using high frequency gas measurements and stable isotopes
Authors: Riis Christiansen Jesper , Röckmann Thomas , Popa Elena , Sapart Celia , Juncher Jørgensen Christian
Published: March 2020

Ice sheets and glaciers play an important role for the global carbon cycle through the exchange of their subglacial carbon with the proglacial aquatic environment and the atmosphere in the form of CH4 and CO2. However, the subglacial environment below ice sheets and glaciers is largely inaccessible from the surface and hence we know very little about the carbon turnover processes in these extreme habitats that lead to this carbon export.

Biological CH4 production and oxidation has been found in subglacial sediments across Canada, Antarctica, west Greenland and at the center of the Greenland Ice sheet. This points at a common glacial process for gaseous CH4 and CO2 emissions, but this knowledge is backed by very few direct field observations from two locations in Greenland and one in Iceland. The lack of field based studies is the single most-limiting factor for increasing our understanding of the magnitude and extent of subglacial carbon emission to the atmosphere and its relevance for the global carbon budget.

We present new field measurements suggesting that it is possible to quantify the carbon turnover processes in the subglacial environment using high frequency concentration measurements and stable isotope composition of CH4 and CO2 in gaseous and dissolved form sampled at a subglacial meltwater outlet.

During three field campaigns in the early, mid and late melt season in 2018 and 2019 we measured significantly elevated CH4 and CO2 concentrations in the air and water exiting a subglacial cave system. We devised a field sampling program for retrieval of discrete gas and water samples that allow identification of the original (common) source of the gaseous and dissolved CH4 and CO2 by quantifying the d13C and dH signature of the source.

Our field measurements are amongst the first to directly quantify the emission of CH4 and CO2 to the atmosphere and our isotopic investigations clearly show a biological source of CH4 and its oxidation to CO2 in the subglacial environment and point to a hydrological control on the release of both CH4 and CO2.

These types of data are instrumental to improve the understanding of subglacial carbon processes and design future field investigations to assess its climatic relevance and to narrow the uncertainty of emission estimates.
Uncertainty in decadal precipitation estimates over the Rur catchment
Authors: Rios Gaona Manuel F. , Shrestha Prabhakar , Simmer Clemens
Published: March 2020

Precipitation is an important input for hydrological models. Uncertainty in its spatiotemporal variability is a major error source for forecasts generated with distributed hydrological models, because this uncertainty propagates non-linearly into simulated soil moisture patterns, groundwater table depths, discharge and surface energy flux partitioning. Thus, it is imperative to use accurate rainfall datasets that reproduce rainfall's intrinsic highly-spatiotemporal variability to obtain better forecasts from hydrological models.

In this study, we present the evaluation of the high-resolution precipitation product RADKLIM against precipitation from the COSMO-DE analysis over the Rur catchment, in western Germany, at a decadal time scale (2007-2015). RADKLIM is the climate version of the quantitative precipitation estimation product RADOLAN developed by the German national weather service (DWD, Deutscher Wetterdienst) by adjusting radar-derived estimates to gauge observations. Its spatiotemporal resolution is ~1x1 km and 5 minutes. The hourly COSMO-DE analysis precipitation data is obtained from the German weather forecast model (also available from DWD) with a spatial resolution of ~2.8x2.8 km. To make a scale-consistent comparison, the RADKLIM product was upscaled to the COSMO-DE resolution.

Overall, the COSMO-DE analysis yields over the studied area 50% more of the average precipitation of the RADKLIM product. The highest biases (COSMO-DE over RADKLIM) predominantly occur during afternoon (i.e., 15:00 - 21:00), and in the summer season; whereas the negative biases predominantly occur during autumn, with their highest in the early afternoon (i.e., 12:00 - 18:00).
The diatom flora of Lake Lisan (Israel): a preliminary investigation
Authors: Hartung Hannah , Reed Jane M. , Litt Thomas
Published: March 2020

The Eastern Mediterranean, and the southern Levant in particular, is a key region for palaeoclimatological and palaeoenvironmental research due to its highly complex topography and climatic variability. Our understanding of environmental variability and its possible drivers, and the interaction with migration processes of modern Homo sapiens from a source area in Africa to Europe, is still limited. This is partly because continuous sediment records of sufficient age are rare across the Mediterranean Basin. The deposits of the Dead Sea represent an ideal archive to investigate palaeoenvironmental conditions during human migration phases in the Last Glacial period (MIS 4-2). 

Diatoms (single-celled siliceous algae, Bacillariophyceae) have well-recognised potential to generate high-quality palaeolimnological data, especially in closed-basin saline lakes, but they remain one of the least-exploited proxies in Eastern Mediterranean palaeoclimate research. Here, we present preliminary results of a low-resolution diatom study derived from analysis of sediment deposits of Lake Lisan, the last glacial precursor of the Dead Sea. Sediment cores were recovered during an ICDP campaign in 2010/2011 from the centre of the modern Dead Sea. 18 sediment samples were analysed to investigate (a) the preservation of diatom valves in various evaporitic deposits (b) possible shifts in diatom species composition of Lake Lisan during the Last Glacial period, and (c) if diatoms can be used as proxy indicator for lake-level and, thus, palaeoclimate reconstruction. We focus on a prominent lake-level high stand of Lake Lisan at around 28-22 ka BP, which resulted in the merging Lake Lisan and freshwater Lake Kinneret.

First results show that the diatom preservation is exceptionally good in evaporitic deposits of the sediment cores from Lake Lisan, which is contradictory to the available literature. In contrast to Holocene deposits from the Dead Sea, diatoms are abundant in all analysed samples from laminated deposits from Lake Lisan: the diatom flora is dominated by halophilous benthic diatoms, such as Amphora spp., Halamphora spp. and Nitzschia spp. In phases of lake-level high stands of Lake Lisan, the diatom flora shifts towards a more plankton-dominated freshwater flora containing Aulacoseira spp. and taxa from the Cyclotella-ocellata-species complex.
Controls of the Transient Climate Response to Emissions: effects of physical feedbacks, heat uptake and saturation of radiative forcing
Authors: Williams Ric , Ceppi Paulo , Katavouta Anna
Published: March 2020

The surface warming response to carbon emissions, defines a climate metric, the Transient Climate Response to cumulative carbon Emissions (TCRE), which is important in estimating how much carbon may be emitted to avoid dangerous climate. The TCRE is diagnosed from a suite of 9 CMIP6 Earth system models following an annual 1% rise in atmospheric CO2 over 140 years.   The TCRE   is nearly constant in time during emissions for these climate models, but its value   differs between individual models. The near constancy of this climate metric is due to a strengthening in the surface warming per unit radiative forcing, involving a weakening in both the climate feedback parameter and   fraction of radiative forcing warming the ocean interior, which are compensated by a weakening in the radiative forcing per unit carbon emission from the radiative forcing saturating with increasing atmospheric CO2. Inter-model differences in the TCRE are mainly controlled by the   surface warming response to radiative forcing with large inter-model differences in physical climate feedbacks dominating over smaller, partly compensating differences in ocean heat uptake. Inter-model differences in the radiative forcing per unit carbon emission   provide smaller inter-model differences in the TCRE, which are mainly due to differences in the ratio of the radiative forcing and change in atmospheric CO2 rather than from differences in the airborne fraction.     Hence, providing tighter constraints in the climate projections for the TCRE during emissions requires improving estimates of the physical climate feedbacks,   the rate of ocean   heat uptake, and how the radiative forcing saturates with atmospheric CO2.
IBSE approach to study climate change from 90 degrees
Authors: Lugaro Elena
Published: March 2020

 

Scientific evidence of climate warming is today clear and well admitted within the scientific community. It is crucial to educate students about the climate crisis we are facing and the consequences that will occur at global level. Climate science is a complex topic, involving a cross-curricular learning experience linking biology, geology, physics and chemistry.  Within such a complex theme, Polar Science plays a crucial role to understand how global warming and climate change are affecting and will affect our planet. Polar Regions are indeed among the most fragile and vulnerable areas, regulating the equilibrium of the whole planet, and the effects of global warming are already showing great changes in these regions.

In this work, the IBSE (Inquiry Based Science Education) approach has been proposed to 14-16 years old students, to analyse how climate change is affecting the North Pole and South Pole, and which are the effects on the planet. Within this approach, students work independently, learning through experiments planned by themselves about the key role the Polar Regions play in the Earth’s climate system. They conducted some experiments regarding two major processes that contribute to sea level rise, by establishing whether land ice, sea ice or both contributes to sea level rise, and by determining whether the warming of the oceans contributes to sea level rise.

This test has shown valuable results about the involvement of the students and their understanding of the processes occurring at the Polar Regions and their links with the whole Earth’s climate system. With the IBSE approach, students practice and experiment several   skills they do not usually use such as working in a team, communicate and interact with other students to answer question, formulate hypothesis, share their ideas and collaborate in a group to find methodologies and possible solutions. Moreover, the design of the experiments made up by themselves has revealed to be a major advance to make the students more aware of the key role the Polar Regions play in the Earth’s climate system. IBSE approach, student-centered and problem-centered, has confirmed to be a valuable tool to encourage creativity, innovation and collaboration in the classroom, engaging and motivating pupils.

 
Non-Extensive Statistical Analysis of Energetic Particle Flux Enhancements Caused by the Interplanetary Coronal Mass Ejection-Heliospheric Current Sheet Interaction
Authors: Pavlos Evgenios , Malandraki Olga , Khabarova Olga , Karakatsanis Leonidas P. , Pavlos George P. , Livadiotis George
Published: March 2020

In this study we use theoretical concepts and computational-diagnostic tools of Tsallis non-extensive statistical theory (Tsallis q-triplet: qsen, qrel, qstat), complemented by other known tools of nonlinear dynamics such as Correlation Dimension and surrogate data, Hurst exponent, Flatness coefficient, and p-modeling of multifractality, in order to describe and understand Small-scale Magnetic Islands (SMIs) structures observed in Solar Wind (SW) with a typical size of ~0.01–0.001 AU at 1 AU. Specifically, we analyze ~0.5 MeV energetic ion time-intensity and magnetic field profiles observed by the STEREO A spacecraft during a rare, widely discussed event. Our analysis clearly reveals the non-extensive character of SW space plasmas during the periods of SMIs events, as well as significant physical complex phenomena in accordance with nonlinear dynamics and complexity theory. As our analysis also shows, a non-equilibrium phase transition parallel with self-organization processes, including the reduction of dimensionality and development of long-range correlations in connection with anomalous discussion and fractional acceleration processes can be observed during SMIs events.
Evaluation of model-data mismatch errors in the CarboScope-Regional Inversion System
Authors: Koch Frank-Thomas , Munas Saqr , Roedenbeck Christian , Gerbig Christoph
Published: March 2020

With an increasing network of atmospheric stations that produce a constant data stream, top-down inverse transport modelling of GHGs in a quasi-operational way becomes feasible. The CarboScope-Regional inversion system embeds the regional inversion, within a global inversion using the two-step approach. The regional inversion consists of Lagrangian mesoscale transport from STILT, prior fluxes from the diagnostic VPRM biosphere model, and anthropogenic emissions from a combination of EDGAR v4.3 with the annually updated BP statistical report. Regional ocean fluxes were derived from the CarboScope ocean flux product based on SOCATv2019 data. The inversion uses atmospheric observations from 44 stations to infer biosphere-atmosphere exchange. The regional domain covers most of Europe (33 – 73N, 15W – 35E) with a spatial resolution of 0.25 degree for fluxes and 0.5 degree for flux corrections inferred by the inversion (i.e. the state space).
One of the critical parameters is the assumed uncertainty of the observations, and the major contribution to this is the model-data mismatch error, or representation error. Within CarboScope-Regional, this model-data mismatch error is specified differently for different station types, such as tall towers, mountain or coastal stations, etc. To evaluate the validity and appropriateness of these assumed uncertainties, a leave-one-out cross-validation is applied for a single year, using all stations except one for the inversion, and comparing posterior concentrations predicted for the omitted station with the observed concentrations. Results of this cross-validation will be presented separately for the different station types, and will be used to evaluate the magnitude of the assumed model-data mismatch errors.
Automatic Earthquake Detection and De-noising for Distributed Acoustic Sensing: Examples from On-land and Underwater Fibers
Authors: Lior Itzhak , Mata Daniel , Guerin Gauthier , Rivet Diane , Sladen Anthony , Ampuero Jean-Paul
Published: March 2020

The use of underwater optical fibers, such as those currently traversing most of the world's oceans, for distributed acoustic sensing (DAS) holds great potential for seismic monitoring by complementing on-land seismic observations, especially near underwater faults. The analysis of underwater DAS records presents special challenges due to the noisy environment and the uneven cable-seafloor coupling. To fully exploit the potential of these records, automatically detecting and extracting seismic signals is imperative. To this end, a new automatic earthquake detection scheme is presented, based on waveform-similarity. Cross correlations between nearby records along the fiber are continuously calculated in short overlapping intervals. Earthquakes are detected as abrupt increases in cross correlation values over large segments of the cable. This procedure is applied to records of four existing fibers: one on land (Near Teil, south of France) and three underwater (one in Toulon, south of France, and two in Pylos, south-west Greece). Detected earthquakes are compared to earthquake catalogs and detection thresholds are obtained. That several of the detected earthquakes do not appear in any earthquake catalog demonstrates the proposed method's robustness. The cross correlation time shifts are then used to perform moveout corrections to the time series and phase weighted stacking (PWS) is applied to groups of neighboring traces. Unlike simple stacking approaches, PWS significantly enhances signal to noise ratios, allowing for more precise earthquake analysis and characterization. Further developing and applying such automatic techniques to ocean bottom fibers will enhance the performance of earthquake early warning systems, improving alert times for earthquakes occurring on underwater faults.
Microfaulting by early diagenesis of micritic continental carbonates - dilatant and compactive shear localization (Montpellier area, France)
Authors: Ballas Grégory , Girard Flavia , Caniven Yannick , Soliva Roger , Celerier Bernard , Mayolle Sylvain , Hemelsdael Romain , Loggia Didier , Gay Aurélien , Lopez Michel , Seranne Michel
Published: March 2020

Microfaults formed in continental carbonates reveal poorly known mechanisms of shear localization induced by early diagenesis during compaction. These faults are characterized by sinuous shape, bed-controlled, pervasive distribution, no calcite precipitation, and mainly disaggregation processes. Two main sets were described: (1) The first set is composed by normal-sense, high-angle microfaults affecting the top of carbonate beds showing undulating pedogenic bed surface. They show porosity increase and are sometimes organized in polygonal patterns. Their occurrence seems related to overconsolidation of pedogenic surface and density inversion – phreatic loading – fluid expulsion processes in the surficial carbonate bed. (2) The second set is composed by low-angle compactive microfaults with large slickenlines and incipient shear-offset. Their organization within two conjugate systems (normal-sense set and strike-slip set) almost contemporaneous is consistent with a NS extension following the slope induced by the basin subsidence to the south. Their occurrence seems related to vertical loading below few meters depth and occurred by shear-enhanced compaction and incipient pressure-solution process. The presence of such structures gives news information concerning dilatant or compactive shear processes and rheological properties of micritic carbonates during early diagenesis.

 
Mapping the geogenic radon potential for Germany by machine learning
Authors: Petermann Eric , Meyer Hanna , Nussbaum Madlene , Bossew Peter
Published: March 2020

The radioactive gas radon (Rn) is considered as an indoor air pollutant due to its detrimental effects on human health. Radon is known as the second most important cause for lung cancer after tobacco smoking. The dominant source of indoor Rn is the ground beneath the building in most cases. Following the European Basic Safety Standards, all EU Member States are required to delineate Rn priority areas, i.e. areas with increased risk of high indoor radon concentrations. One possibility to this end is using the “geogenic Rn potential” (GRP), which quantifies the availability of geogenic Rn for infiltration into buildings. The GRP is defined as a function of Rn concentration in soil gas and soil gas permeability.

In this study we used > 4,000 point measurements across Germany in combination with ~50 environmental co-variables (predictors). We fitted machine learning regression models to the target variables Rn concentration in soil and soil gas permeability. Subsequently, the GRP is calculated from both quantities. We compared the performance of three algorithms: Multivariate Adaptive Regression Splines (MARS), Random Forest (RF) and Support Vector Machines (SVM). Potential candidate predictors are geological, hydrogeological and soil landscape units, soil physical properties, soil chemical properties, soil hydraulic properties, climatic data, tectonic fault data, and geomorphological parameters.

The identification of informative predictors, tuning the model hyperparameters and estimation of the model performance was conducted using a spatial 10-fold cross-validation, where the folds were split by spatial blocks of 40*40 km. This procedure counteracts spatial autocorrelation of predictor and response data and is expected to ensure independence of training and test data. MARS, RF and SVM were evaluated in terms of its prediction accuracy and prediction variance. The results revealed that RF provided the most accurate predictions so far. The effect of the selected predictors on the final map was assessed in a quantitative way using partial dependence plots and spatial dependence maps. The RF model included 8 and 14 informative predictors for radon and permeability, respectively. The most important predictors in the RF model were geological and hydrogeological units as well as field capacity for radon and soil landscape, geological and hydrogeological units for soil gas permeability.
Bridging the Future of Earth System Modelling – the ESM Summer School 2019
Authors: Cristini Luisa , Sausen Robert , Mertens Mariano , Wieters Nadine , Pasqualetto Sara
Published: March 2020

The Earth System Modelling Capacity (ESM) project is a 3-year effort funded by the Helmholtz Association started in April 2017 and involving eight research centres across Germany. The project has a strong knowledge transfer component aiming to provide decision-makers with relevant tools in order to face grand challenges in the near future and to support early career scientists (PhD students and early career postdoctoral researchers) from ESM project partner centres as well as the national and international community in developing and strengthening their knowledge on Earth system modelling, as one of the primary efforts to establish a legacy for the project.

From 9th to 19th of September 2019, the ESM summer school was held in Bad Aibling (Germany) with 50 participating students from 26 institutes placed all over the world. A core objective of the school was to train and educate early-career scientists from a wide range of discipline and with a diverse international and gender background to apply cutting edge science in the study of the Earth system and at the same time to engage in a stimulating exercise of knowledge transfer for the project.

During the 10-day summer school, students had four lectures daily about topics related to the Earth system and its components, from atmospheric dynamics to terrestrial modelling, from the modelling of waves and oceans to that of ice sheets and glaciers. The school included practical exercises and hands-on sessions that involved coding and building mini-cluster computers, building on the advanced technical knowledge of ESM partners and scientists. The lectures were held by thirty researchers from the ESM Project’s partner institutes and beyond. Two poster sessions were also organized, where students had the chance to present their work to their peers and to the senior scientists, exchange experiences, share results and receive feedbacks from fellow students and lecturers.

In this presentation, we will present the concept and key features of the summer school, content and organisation, and also offer the students’ feedback collected after the school in an effort to showcase an example of how summer schools remain a powerful mean to value diversities and create an inclusive environment in (Earth system) science.
Downscaling of Precipitation Forecasts Based on Single Image Super-Resolution
Authors: Ji Yan , Zhi Xiefei , Tian Ye , Peng Ting , Huo Ziqiang , Ji Luying
Published: March 2020

High spatial resolution weather forecasts that capture regional-scale dynamics are important for natural hazards prevention, especially for the regions featured with large topographical variety and local climate. While deep convolutional neural networks have made great progress in single image super-resolution (SR) which learns mapping relationship between low- and high- resolution images, limited efforts have been made to explore the potential of downscaling in this way. In the study, three advanced SR deep learning frameworks including Super-Resolution Convolutional Neural Network (SRCNN), Super-Resolution Generative Adversarial Networks (SRGAN) and Enhanced Deep residual networks for Super-Resolution (EDSR) are proposed for downscaling forecasts of daily precipitation in southeast China (100°E -130°E, 15°N -35°N). The SR frameworks are designed to improve the horizontal resolution of daily precipitation forecasts from raw 1/2 degrees (~50km) to 1/4 degrees (~25km) and 1/8 degrees (~12.5km), respectively. For comparison, Bias Correction Spatial Disaggregation (BCSD) as a traditional SD method is also performed under the same framework. The precipitation forecasts used in our work are obtained from different Ensemble Prediction Systems (EPSs) including ECMWF, NCEP and JMA which are provided by TIGGE datasets. A group of metrics have been applied to assess the performance of the three SR models, including Root Mean Square Error (RMSE), Anomaly Correlation Coefficient (ACC) and Equitable Threat Score (ETS). Results show that three SR models can effectively capture the detailed spatial information of local precipitation that is ignored in global NWPs. Among the three SR models, EDSR obtains the optimum results with lower RMSE and higher ACC which shows better downscaling skills. Furthermore, the SR downscaling methods can be extended to the statistical downscaling for other predictors as well.
A typology of compound weather and climate events
Authors: Zscheischler Jakob , Martius Olivia , Westra Seth , Bevacqua Emanuele , Raymond Colin , Horton Radley , van den Hurk Bart , AghaKouchak Amir , Jézéquel Aglaé , Mahecha Miguel , Maraun Douglas , Ramos Alexandre , Ridder Nina , Thiery Wim , Vignotto Edoardo
Published: March 2020

Weather- and climate-related extreme events such as droughts, heatwaves and storms arise from interactions between complex sets of physical processes across multiple spatial and temporal scales, often overwhelming the capacity of natural and/or human systems to cope. In many cases, the greatest impacts arise through the ‘compounding’ effect of weather and climate-related drivers and/or hazards, where the scale of the impacts can be much greater than if any of the drivers or hazards occur in isolation; for instance, when a heavy precipitation falls on an already saturated soil causing a devastating flood. Compounding in this context refers to the amplification of an impact due to the occurrence of multiple drivers and/or hazards either because multiple hazards occur at the same time, previous climate conditions or weather events have increased a system’s vulnerability to a successive event, or spatially concurrent hazards lead to a regionally or globally integrated impact. More generally, compound weather and climate events refer to a combination of multiple climate drivers and/or hazards that contributes to societal or environmental risk.

Although many climate-related disasters are caused by compound events, our ability to understand, analyse and project these events and interactions between their drivers is still in its infancy. Here we review the current state of knowledge on compound events and propose a typology to synthesize the available literature and guide future research. We organize the highly diverse event types broadly along four main themes, namely preconditioned, multivariate, temporally compounding, and spatially compounding events. We highlight promising analytical approaches tailored to the different event types, which will aid future research and pave the way to a coherent framework for compound event analysis. We further illustrate how human-induced climate change affects different aspects of compound events, such as their frequency and intensity through variations in the mean, variability, and the dependence between their climatic drivers. Finally, we discuss the emergence of new types of events that may become highly relevant in a warmer climate.
Representing women in science: designing laboratory activities based on women’s work
Authors: Maciel Susanne , Braga Alcantara Gustavo , Gomide Caroline , Franca George Sand
Published: March 2020

The gender gap is measured globally by the World’s Economic Forum in four key areas: economic participation and opportunity, educational attainment, health and survival, and political empowerment. According to the 2020 Global Gender Gap index, it will take us nearly 100 years to get gender parity. Also according to the World’s Economic Forum report, if we consider the fastest growing professions of the future, a critical data reveals a problematic situation: women form only 26% among people with AI and data skills, 15% among people with engineering skills and 12% among those with cloud computing skills. Education is thus an important key to embed gender parity into the future. Today, 55% of working-age women are in the labour market, against 78% of men. This gap can increase even more if we do not include young girls in Science, Technology, Engineering and Mathematics (STEM) courses. Gender issues concerning access, permanence and ascension of women in STEM careers, in general, relates to various aspects. Between other elements, we point the underrepresentation of women in science communications, sexual or moral harassment caused by professors and colleagues during undergraduate and graduate ages, or the overload of housework for girls, when compared to boys, during early school ages. In other words, gender imbalance in STEM careers is the result of a series of structured oppression suffered by women of all ages. In this context, we developed a set of laboratory routines based on the work of female scientists, directed to students from 12 to 18 years old, at the Planaltina Campus of the University of Brasília. The University of Brasília is the 4th most prominent university in Brazil, and its resources are distributed between four camps. Planaltina Campus is situated 40 km away from the main campus. In recent research, it has been shown that only 30% of Planaltina young population has the intention of accessing the university. From those, only 15% pretend to study exact and earth sciences. Thinking about the World’s Economic Forum alert about professions of the future, we felt the necessity of promoting a program to capacitate, inform and demystify tabus from exact sciences among high school students, especially among girls. The activities start with the rescue of a prominent female scientist in the field that will be worked on that day, followed by a pedagogical transcript of her work. We conduct a hands-on laboratory within the University of Brasília infrastructure. The idea of the labs is to work as a school reinforcement on natural sciences disciplines, and to give visibility to women in science, improving issues such as underrepresentation and mistrust in women work. We will present the results of an implemented questionnaire and also comment about the challenges of our experience.