bluuebunny/crossref_metadata_2025 huggingface dataset:
Mobility of bi-disperse sediment beds in bedload transport
Authors: Chassagne Rémi , Maurin Raphaël , Chauchat Julien , Frey Philippe
Published: February 2023

Bedload transport has major consequences for public safety, water resources and environmental sustainability. In mountains, steep slopes drive an intense transport of a wide range of grain sizes implying size sorting or segregation largely responsible for our limited ability to predict sediment flux and river morphology. Size segregation can lead to very complex and varied morphologies of bed surface and subsurface, including armouring, and can drastically modify the fluvial morphology equilibrium.In this work, the mobility of bidisperse beds is studied with coupled fluid-Discrete Element Method (DEM) simulations of bedload transport. Initially, a large particle layer is deposited over a 10% slope bed made of small particles. A gravity-driven water free surface flow induces a downslope shear-driven granular flow of the erodible bed. It is observed that, for the same water flow conditions, the bedload transport rate is higher in the bidisperse configuration than in the monodisperse one. Depending on the Shields number and on the depth of the interface between small and large particles, different transport phenomenologies are observed, ranging from no influence of the small particles to small particles reaching the bed surface due to diffusive remixing. In cases where the small particles hardly mix with the overlying large particles and for the range of studied size ratios (r < 4), it is shown that the increase of mobility of the sediment bed is a granular effect, which can be explained within the mu(I) rheology framework. The buried small particles are more mobile than larger particles and play the role of a “conveyor belt” for the large particles at the surface. Based on rheological arguments, a simple predictive model is proposed for the additional transport in the bidisperse case. It reproduces quantitatively the DEM results for a large range of Shields numbers and for size ratios smaller than 4.Finally, a phenomenological map is proposed. It presents the different transport regimes of bidisperse mixtures, depending on the mechanism responsible for the mobility of the small particles.
Analysis of the wind response to resolved versus parametrized turbulent orographic drag over moderately complex terrain.
Authors: Quimbayo-Duarte Julian , Schmidli Juerg , Kohler Martin , Schlemmer Linda
Published: February 2023

The response of the lower atmosphere to resolved versus parametrized orographic drag over moderately complex terrain is investigated. Typically, larger terrain scales may trigger propagating gravity waves and generate flow blocking, while the smaller scales (smaller than 5 km) may modify the turbulent atmospheric boundary layer leading to turbulent orographic form drag (TOFD). We perform high-resolution numerical simulations to evaluate the ability of a TOFD parametrization to reproduce the impact of small-scale orographic features on the flow over moderately complex terrain. The tool selected to perform the simulations is the Icosahedral Nonhydrostatic (ICON) numerical model, a unified modelling system for global numerical weather prediction (NWP) and climate studies. In the present study, the model is used in its limited-area and Large Eddy Simulation (LES) modes. In the TOFD parametrization (NWP), the surface stress and the vertical distribution of the resulting momentum flux are formulated in terms of the orography spectrum, meaning that it only depends on the statistical properties of the orography in the box (more specifically, only on the variance of the sub-grid scale orography).

First, the simulations using different grid spacings, from the km scale to the 100 m scale, are evaluated with respect to data collected during the intensive observational period (IOP) of the Perdigão field experiment. The km-scale simulations in NWP mode are run continuously for the complete 49-day IOP using ERA5 data for initial and boundary conditions. The large-eddy simulations, at O(100 m) grid spacing, are run for selected periods nested into the NWP runs. The impact of the resolved orography on the wind field is derived by considering the difference between the high-resolution experiments with high (130 m) and the experiment with low (1 km) resolution orography. This is then compared with the impact of parametrized TOFD, deduced from NWP-resolution experiments with and without TOFD parametrization. The experiments focus on a moderately complex terrain to the north of the Perdigão site, the Serra da Estrela mountain range. 

Preliminary results show an important contribution of the TOFD parametrization (in terms of the accumulate TOFD tendency of wind) when the wind flow is aligned perpendicular to the mountain range, which is frequently observed during the second phase of the IOP characterized by weak synoptic conditions. During such periods, the simulation using the TOFD parametrization tends to be closer to the high resolution LES simulation, suggesting that the TOFD parametrization has a net positive effect on the simulations.
The soil CO2 emission at the three most common forest habitat types in Poland
Authors: Chojnicki Bogdan , Poczta Patryk , Harenda Kamila , Dłużewski Paweł , Józefczyk Damian
Published: February 2023

The soil CO2 emission is one of the most important parts of forest carbon balance, and accurate estimation of this flux is fundamental for appropriate forest management aimed at adaptation and mitigation of climate change. The soil carbon dioxide flux density is determined by different factors, e.g. soil temperature, humidity, and C-content. The Polish forest habitats classification (based on the climate and soil conditions) provides the practical basis for the effective extrapolation of local carbon dioxide emission observations to larger areas. Thus, the main goal of this study was the estimation of the annual dynamics of the soil CO2 emission at three of the most common forest habitats and to select the most reliable model that can be commonly applied to managed forests. There were three experimental sites selected for this study, and they represented the following forest habitats: optimal conditions for pine forest (OP), rich conditions for pine forest (RP) optimal conditions for mixed oak and pine forest (OOP). These three habitats represent 66% of forested areas in Poland. The sites were located in Oborniki Forest Inspectorate in the Greater Poland Voivodship, Western Poland. The CO2 emission was measured by means of the manual dynamic opaque chamber attached to the infrared gas analyzer (LI-840 LI-COR, USA). There were 3 collars (25 cm diameter) inserted about 15 cm depth into the ground at each site, and the measurement campaigns were carried out from 16th of March 2022 8th of March 2023, at 3-week intervals. The soil measurement system (TMS-4, TOMST, Czechia) was applied for discrete (15-minute interval) measurements of the air and soil temperature and soil water content at each collar. Additionally, soil analysis was made at each site. The initial analysis of obtained results shows that the model based on both soil temperature and soil water content can be considered the most accurate and reliable. The richest forest habitat (OOP) with the highest soil C-content is characterized by the highest annual soil CO2 emission.
Extending the age model for Lake Bosumtwi (Ghana) to reconstruct West African climate and dust dynamics during the last million years
Authors: Vinnepand Mathias , Zeeden Christian , Noren Anders , Kaboth-Bahr Stefanie , Gosling William , Kück Jochem , Wonik Thomas
Published: February 2023

Lake Bosumtwi was created after a meteorite impact 1.07 Ma ago in an area that is highly susceptible for climate changes due to shifts of the tropical rain belt, as well as variation in dust dynamics. The sedimentary sequence records such changes in the tension field between the North African Monsoon (humid, wet) and the Harmattan (dry and dusty winds from the Sahara) and has been intensively studied. Drilling in 2004, supported by the International Continental Scientific Drilling Program (ICDP), recovered downhole logging data and sediment cores that allow for the analysis of the complete ~300 m lacustrine sequence. Yet, detailed climatic and environmental reconstructions for the record have not been completed, mostly due to the absence of a robust age model beyond 500 ka. In 2022, we obtained core scanning natural gamma ray data of the ~300 m lacustrine sedimentary sequence. Based on this data, we are generating an astronomical age model that can be directly compared to the independently dated sections, but extends farther back in time. Our age model will provide critical chronologic context for the numerous existing and new proxy data that illuminate past changes in climate, environment, and ecosystems. This breakthrough will allow a robust framework to analyse climatic interferences with archaeological findings that might shed new light on habitat availability for our ancestors in tropical Western Africa. 
Response of the ocean carbon and oxygen cycles to climate change and anthropogenic nutrient inputs
Authors: Yamamoto Akitomo , Hajima Tomohiro , Yamazaki Dai , Noguchi-Aita Maki , Ito Akinori , Kawamiya Michio
Published: February 2023

Nutrient inputs from the atmosphere and rivers to the ocean are increased substantially by human activities. These increasing inputs of nutrients from human activities promote oceanic NPP, potentially partially counteracting decreases caused by climate change. Then, increases in export of organic matter to the ocean interior and its decomposition consumes dissolved oxygen. Therefore, nutrient inputs to the ocean promote carbon uptake and amplify climate-driven ocean deoxygenation. However, the previous generation of Earth system models that participated in the Coupled Model Intercomparison Project Phase 5 (CMIP5), which contributed substantially to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, did not account for anthropogenic nutrient inputs to the ocean. Several CMIP phase 6 (CMIP6) Earth system models do consider anthropogenic nutrient inputs to the ocean for the historical period, but their impact on ocean biogeochemical cycles has not been fully assessed, even for individual Earth system models. Therefore, our understanding of the impact of such perturbations on ocean biogeochemistry is even less complete than that associated with climate change. In particular, the quantitative relationship between the effects of climate change on ocean biogeochemical cycles and those of anthropogenic nutrient inputs remains poorly understood.In this study, using historical simulations by one of the CMIP6 models (MIROC-ES2L) that considers anthropogenic nutrient inputs, we demonstrate that the contribution of anthropogenic nutrient inputs to past changes in global oceanic productivity, carbon uptake, and deoxygenation is of similar magnitude to the effect of climate change. In particular, two noteworthy results are obtained: (1) that anthropogenic fertilization could more than counteract the expected decrease in NPP caused by ocean warming and stratification for the historical period, and (2) that it could accelerate climate-driven deoxygenation in the upper ocean, helping to close the gap between models and observations. Additionally, current estimation of the imbalance in the carbon budget could be explained partially by increase in oceanic carbon uptake associated with anthropogenic nutrient inputs to the ocean. These improvements provide support regarding the significant contribution of anthropogenic nutrient inputs to global changes in ocean biogeochemistry. Considering the effects of both nutrient inputs and climate change is crucial in assessing anthropogenic impacts on ocean biogeochemistry.
Precipitation weather typing over the South Pacific: application to the TRMM satellite product calibration
Authors: Mirones Oscar , Bedia Joaquín , Fernández-Granja Juan A. , Herrera Sixto , Van Vloten Sara O. , Pozo Andrea , Cagigal Laura , Méndez Fernando J.
Published: February 2023

In the South Pacific region, the precipitation patterns are mostly driven by a number of processes operating at spatial and temporal scales. One of the most important features is the South Pacific Convergence Zone (SPCZ).Five Daily Weather Types (WT) of precipitation are presented, based on Principal Component Analysis (PCA) and k-means clustering using ERA5 precipitation and atmospheric circulation variables such as mean sea-level pressure (SLP), day-to-day difference of mean daily SLP or northward and eastward 10-m wind component fields, able to capture distinct precipitation spatio-temporal patterns, interpretable in terms of salient regional climate features such as the SPCZ state and tropical cyclone activity. We then undertake a weather-type conditioned calibration of the TRMM (Tropical Rainfall Measuring Mission) product using in-situ rain gauge records from the PACRAIN database as reference. “Conditioning” is here based on applying separate statistical corrections for each of the generated WTs, since biases might be dependent on specific atmospheric situations that can be partially captured by the clustering procedure, thus adapting the correction factors to specific synoptic conditions. Our results indicate that the WT-conditioned calibration provides an overall marginal added value over the unconditioned approach, although it makes a significant difference for a better correction of extreme rainfall events, critical in many impact studies. The approach can be extended to compound extreme events, in which several variables are involved (e.g. precipitation, sea level, wind, etc.), in order to better preserve multi-variable consistency.
Quality assessment of subseasonal soil moisture forecasts for agricultural applications in Germany
Authors: Leppelt Thomas
Published: February 2023

Rain-fed agriculture constitutes more than 95 % of cropland in Germany. It depends heavily on rainfall patterns and the water storage capacities of top soil layers. Intense summer droughts with long-lasting lack of precipitation leads to yield loss in wheat, corn and sugar beet production in the last years 2018, 2019, 2020 and 2022. Hence, these drought events increase the requirement of long-range forecasts for precipitation and soil moisture, which could provide useful predictions for agricultural applications.Here a coupled modelling attempt is presented, that combines the extended-range ENS-forecasts from the European Centre for Medium-Range Weather Forecasts (ECWMF) with the soil-vegetation-atmosphere-transfer (SVAT) impact model AMBAV to simulate the top soil moisture for subseasonal forecasts on a downscaled 5x5 km grid in Germany. A quality assessment of forecast ensemble means from July 2022 to November 2022 has been done with the corresponding hindcasts for the preceding 20 years. The mean squared error skill score (MSESS) of weekly averages reveals a significant forecast skill up to 4-6 weeks for soil moisture in the upper 60 cm in comparison to an AMBAV analysis run based on gridded weather station data. In contrast, the precipitation forecast skill is much lower and achieve only adequate forecast skill with lead times up to two weeks. Due to the low variability and persistence of soil moisture values, it is proposed, that this storage variable is well suited for climate services like agricultural drought predicting systems on subseasonal time scales. It could offer guidance with sufficient reliability for medium-term management adjustments like irrigation planning or reduced fertilizer usage in case of expected severe drought periods. Overall, the results of this study show the potential of subseasonal soil moisture forecasts for agricultural applications. Further research is needed to verify these findings and to extend the forecast analysis period to the entire year. Then the impact modelling system might contribute to the adaptation of agriculture to climate change in Germany.
Modeling large-scale biocide transfer to urban groundwater
Authors: Linke Felicia , Zimmermann Felix , Lange Jens
Published: February 2023

Biocides used as film protection in paints and renders wash off from facades and enter the urban water cycle. They can also reach urban groundwater, diffusely or at specific locations via urban stormwater infiltration systems (SIS). Up to now, there is limited knowledge to estimate biocide input to urban groundwater at larger scales. This study focuses on an urban area of 38ha and models biocide input to groundwater, including SIS. The aim is to determine preferential input locations, SIS retention capacities, transport and degradation of biocides in the saturated zone. The study area is located in southwestern Germany in the city of Freiburg. Due to a contamination site with chlorinated hydrocarbons (CHC), numerous urban groundwater monitoring wells exist. Hence existing monitoring data is substantial, including groundwater levels, biocide and CHC samples over a time period of at least seven years. The biocide terbutryn is chosen as a model biocide, as it is commonly used in paint and renders and was previously detected in the study area. The present study uses a model chain to reproduce biocide emission and transfer. First, terbutryn leaching is estimated using the model COMLEAM. Then, the urban water balance and groundwater recharge are calculated by the model Roger_WB_Urban. Coupling the estimated terbutryn emissions with groundwater recharge patterns provides an estimation of terbutryn inputs to groundwater over time. This pattern is finally used as input for a groundwater model (MODFLOW), which is calibrated with the help of the CHC plume development. First model results confirm groundwater monitoring data and indicate that retention capacities of the investigated SIS are limited, mainly because of shallow groundwater levels. This is reflected by simulated terbutryn concentrations in groundwater which are apparently higher downgradient of the SIS. However, also other input pathways exist. Overall, our model chain helps to understand biocide emission and transfer pathways in urban environments at larger scales and stresses the fact that measures to prevent groundwater contamination are most efficient at the source.
A geochemical perspective on the petrogenesis of charnockites from the western parts of the Palghat-Cauvery Shear Zone, southern India: implications for collisional geodynamics
Authors: Nandan T Nanditha , Chettootty Sreejith
Published: February 2023

The Earth is a dynamic planet that has been evolving ever since it was formed. The formation of protocontinents and their amalgamation to supercontinents and later dispersals are one of the fascinating geologic events during the course of the evolution of Earth. Studies on the assembly and dispersals, therefore, provide insights into the mechanisms of extraction of mantle materials at different time periods, the formation of mountain belts, the recycling of crustal materials, magmatism, metamorphism, etc. The recent supercontinent assembly, namely "Gondwanaland," took place during one of the most dynamic periods of the earth's history, and almost all of the existing continental fragments have records of this great geological event. The Southern Granulite Terrane (SGT) of South India is made up of a variety of crustal blocks and collisional sutures/shears that developed during the period of multiple orogenic cycles from the Mesoarchean to the late Neoproterozoic-Cambrian, including that of Gondwana period. Among this, the Palghat Cauvery Shear Zone (PCSZ) marks a major Neoproterozoic structure of crustal accretion, and it is considered the extension of major terrain boundaries identified in Madagascar and Sri Lanka in the final stages of the Gondwana assembly. Even though there have been plenty of studies carried out to understand the nature of the lower crust, terrain assembly, and shear sense indicators along the PCSZ, most of them are concentrated on the eastern side of the shear zone, and only a few have been carried out in the high-grade western terrain; therefore, unequivocal evidence showing collisional orogenesis is lacking from this terrain. The present study attempts to infer the geochemical characteristics of charnockites from the western parts of the PCSZ in terms of accretionary and/or collision tectonics. The geochemistry suggests that the charnockites are tonalitic to granodioritic in composition and have calc-alkaline affinity, indicating an origin related to collision tectonics. These are the products of granulite-facies metamorphism, most probably of an I-type granitic magma, with a low Rb/Sr ratio and a high Ba/Rb ratio suggesting resemblance with Archaean tonalites, and as a product of the remelting of protoliths of tonalite–trondhjemite–granodiorite (TTG) composition. The whole-rock major and trace element compositions indicate that charnockites are formed as the product of partial melting of garnet amphibolite or eclogite-facies basaltic crust during granulite-grade metamorphism at a lower crustal level during a collisional event.
Droughts influence patterns of human settlements in Africa
Authors: Ceola Serena , Mård Johanna , Di Baldassarre Giuliano
Published: February 2023

Droughts are increasing in frequency and intensity in many African countries. Their occurrences severely affect agricultural production and thus potentially contribute to human displacement. Yet, the way in which droughts influence patterns of human settlements remain poorly understood. Here we show that drought occurrences across Africa are often associated with (other things being equal) human displacements towards rivers and cities. Our results show that 73-81% of African countries exhibit larger human mobility towards water bodies and urban areas during drought conditions, as compared to non-drought periods. This may result into increasing floodplain population, and thus into potentially larger flood losses, or overcrowding urban areas. As such, our results shed light on the interplay between hydrologic extremes and society, bolstering the analysis on the spatiotemporal dynamics of drought risks in a warming world.
Increased seismicity at the beginning of 20th century in the Czech Republic and adjacent areas
Authors: Fojtíková Lucia , Málek Jiří , Prachař Ivan , Lukešová Renata , Kysel Róbert , Vackář Jiří , Valenta Jan , Lachová Barbora
Published: February 2023

The Czech Republic is situated in an intraplate region with low seismicity. The seismic hazard is relatively low but not negligible. A new map of the seismic hazard of the Czech Republic computed using a probabilistic approach is being compiled and will be released in the second half of 2023. As a part of this project new catalogues of earthquakes, both historical (based on macroseismic observations) and instrumental (based on seismograms) were compiled. These include earthquakes on the territory of the Czech Republic and neighboring areas of Slovakia, Austria, Germany and Poland.       When analyzing these new enhanced catalogues, we recognized a period of increased seismicity at the beginning of the 20th century. The annual seismicity rate in this time interval for earthquakes with a magnitude 4 and greater is several times higher than at present. One possible explanation is the inconsistent magnitude determination between the beginning of the 20th century and the present time. Therefore, we re-examine historical seismograms at the beginning of the 20th century and verify their magnitudes. We also compared macroseismic observations of historical earthquakes with modern ones having almost the same magnitude.       We found out that the increased seismicity at the beginning of 20th century is real. During this period, relatively large earthquakes were observed in various source zones in the investigated region. Such earthquakes have not occurred since 1920-1930 to the present. 
Attribution of extreme rainfall associated with the Balkans floods of May 2014
Authors: Podraščanin Zorica , Basarin Biljana , Iles Carley , Daloz Anne Sophie
Published: February 2023

In May 2014, the Balkan Region experienced exceptionally heavy rainfall. Between May 14 and May 19, 2014, there was a devastating flood in Serbia, Croatia, and Bosnia & Herzegovina. The event shattered a number of historical records and seriously endangered economies across the region. The close proximity of human settlements, infrastructure (houses, buildings, bridges), and agricultural land to flood plains further amplified the destructive effects. Although atmospheric thermodynamic and dynamic processes were used to describe this exceptional rainfall event, there was no mention of how climate change may have contributed to it. We show that the probability of this brief and powerful event occurring without human-caused climate change were incredibly low. Our research aims to demonstrate how climate change may have affected the likelihood that this extreme rainfall event will occur as well as to outline the difficulties in doing so. This was accomplished using the methods recommended by the World Weather Attribution (WWA) group. We examine whether and how much human-caused climate change has affected the likelihood and intensity of the rainfall over the Balkans as well as the peak 5-day precipitation in order to achieve this. We consider both historical weather data and climate models with and without anthropogenic forcing. The findings suggested that one of the key elements in determining event likelihood calculations is domain selection. Given the current situation and the possibility for further excessive rainfall over the Balkans, it is critical to enhance water management and lessen vulnerability to extreme rainfall.
 
Acknowledgement:This research was supported by ExtremeClimTwin project, which has received funding from theEuropean Union’s Horizon 2020 research and innovation programme under grant agreement No 952384.
LEO-to-GNSS Laser Interferometer for Space Geodesy with Laser DORIS and Laser SAR
Authors: Svehla Drazen
Published: February 2023

In order to increase the accuracy of precise orbit determination for a single satellite or satellites in LEO formation, we propose using a LEO-to-GNSS laser interferometer, what we call a “laser GNSS receiver”, to measure the Doppler shift with a continuous-wave (CW) laser between LEO and GNSS satellites equipped with SLR arrays (Galileo, GPS, GLONASS, Beidou). LEO orbit is above atmosphere (no  atmospheric attenuation and turbulence in laser signal) and this makes the “laser GNSS receiver” very attractive for future LEO missions. At the EGU and AGU conferences, over the last several years, we have presented the link budget, design and feasibility of such a new instrument in space geodesy and discussed applications in: reference frame missions; gravity field missions; laser atmospheric sounding (above the clouds) and combination with microwave GNSS-RO; time/frequency transfer for ground optical clocks at 10-18 frequency uncertainty (TAI, UTC); and Earth-to-Moon laser interferometry using an ILRS telescope. Here we extend this new instrument in space geodesy to laser DORIS and laser SAR.Laser altimetry is an established technique that uses a pulsed laser to measure a range from LEO orbit to the ground in the nadir direction. In a similar way, interferometric laser tracking could be established on the continuous-wave laser signal transmitted from the LEO orbit in the nadir direction and reflected from the ground. This could be done, e.g., by modulating a microwave-like signal on a CW laser, providing a microwave phase on a laser carrier. The main advantage of the laser SAR/inSAR is that microwave modulation on a laser carrier is not going to be affected very much by the wet delay of the atmosphere and in this way does not require radiometers in LEO to correct atmospheric propagation effects, and instead, they can be corrected a priori using models like those used for the SLR measurements.Therefore, compared to the microwave SAR/inSAR, laser SAR/inSAR opens up the possibility of using the SAR/inSAR technique along with space geodesy techniques if permanent geodetic stations are equipped with the well-defined laser retro-reflectors on the ground. Compared to the pulsed lasers used by ILRS, a continuous-wave laser is more appropriate for higher laser powers since the lower laser peak power avoids damage to the transmitting optics and allows simplified optics with non-mechanical laser beam steering. We present link budget of such a laser DORIS technique to observe Doppler shift from LEO orbit to the ground laser retro-reflectors and laser SAR/inSAR based on laser signal reflected from the ground surface. The IceSAT-2 mission from NASA indirectly confirmed the link budget with the onboard pulsed laser used for laser altimetry, opening up the possibility of a laser SAR/inSAR technique from LEO.
Using (U-Th)/He dating of iron oxides to constrain past weathering episodes
Authors: Heller Beatrix , Gautheron Cécile , Morin Guillaume , Allard Thierry
Published: February 2023

Laterites are deep weathering profiles which develop under tropical and subtropical climatic conditions. Their geochemical and mineralogical composition is strongly influenced by the climatic condition under which they form, whereas the composition of the parental material plays a subordinate role. Due to their long-term stability throughout the intertropical zone, they are archives of past climates. It has been proposed that laterites formed episodically throughout the Earth’s history in periods with very favorable climate, but little is known about the duration, frequency and spatial extent of such weathering events. As different climatic signals are potentially superposed in old and constantly exposed laterites, disentangling of the paleoclimatic information preserved in these archives is a complex task. Since laterites are mainly composed of clay minerals, iron (oxyhydr)oxides and aluminum (oxy)hydroxides, most conventional geochronological methods cannot be applied to those formations. However, hematite and goethite, which are the main components of the ferruginous duricrust that is present in most lateritic profiles, can be dated using the (U-Th)/He method.

This contribution presents an approach which couples (U-Th)/He geochronology of supergene hematite and goethite with high resolution mineralogical and geochemical methods. Our data derives from the South American Guiana shield which has been tectonically stable and in tropical latitudes since the Cretaceous - conditions favorable for the development of thick lateritic profiles. Two coupled data sets from lateritic duricrusts from the northeastern and eastern Guiana shield reveal the existence of several important weathering events during the Cenozoic. Mineralogical and geochemical characteristics of the dated material allow us a deepened insight into weathering processes and conditions by placing mineralogical and geochemical processes into a temporal framework and thereby enables us to extract paleoclimatic information from lateritic iron duricrusts. The results from the eastern part of the shield indicate the existence of three discrete weathering events during the Late Cretaceous / Early Paleocene, the Oligocene and the Middle Miocene that can be related to seasonally contrasted  tropical climate. By contrast, the results from the northeastern Guiana shield are dominated by a Late Neogene weathering event which shows characteristics of more humid climatic conditions.
Study of the fault propagation process in the High Agri Valley area (Southern Apennines)
Authors: Olita Fabio , Prosser Giacomo
Published: February 2023

The area of the High Agri Valley, located in the central part of the Southern Apennines, has been extensively studied in the past, due to the presence of important economic resources and active faults. In particular, attention was focused on the large-scale faults, affecting the allochthonous tectonic units the area, with a direction nearly parallel to the chain axis. Based on that, the previous authors identified two different fault systems located on the opposite sides of the valley. Less attention, however, has been paid to the transversely oriented faults that make up Transverse Tectonic Lines (TTL). The Agri valley is one of the NW-SE elongated basin formed during the extensional phase that, starting from lower Pliocene, affected the Southern Apennines. In the area important structures recorded the brittle and ductile deformation that involves all the tectonic units that make up the Southern Apennines thrust and fold belt. This latter results from the tectonic collision between the African and European plates in the present-day Mediterranean area. These allowed the allochthonous wedge to migrate with NE vergence on the autochthonous Apulian carbonates.The TTL in the eastern part of the High Agri Valley appear to have similar lengths (segments rarely reach 8 km in length) and are characterized by a NE-SW orientation, nearly parallel to the main thrust vergence direction. There are few transverse fault planes directly visible in the field and most of the faults have been deduced from the displacement of stratigraphic contacts as well as from the observation of satellite images. The maximum vertical displacements in the central part of the major fault segments exceed 1500 m, thus allowing us to consider these structures of considerable importance on the scale of the Southern Apennines.The throw profiles derive from the analysis of cut-off lines of formational tops displaced from selected faults obtained from a static 3D model. This allows us to hypothesize its growth pattern and kinematics. Most of the throw profiles of LLTs have a characteristic bell-shaped geometry with greater displacement in the central part that gradually decreases at the tips. Moreover, the observation of the hanging-wall and footwall curves of the cut-off lines of the formational tops allow to hypothesize the kinematics of the studied faults.The analysis of LTTs and throw profiles in fault developed within highly deformed allochthonous Units can be considered as a new approach that can be proposed for further studies in fold and thrust belts. The transverse faults could be interpreted as linkage structures between segments of faults parallel to the chain axis or be confined by the latter which inhibit their lateral propagation. This could also be important in relation to the seismicity of the Southern Apennines as well as in the compartmentalization of aquifers hosting important water resources in the study area.
Mechanisms of salt transport by the advective and tidal oscillatory flux in the macro-tidal estuary, Gyeonggi Bay in South Korea
Authors: Woo Seung-Buhm , Lee Hye Min , Kim Jong Wook , Yoon Byung Il
Published: February 2023

Many estuaries have been damaged by material movements like marine debris, suspended sediment, and pollutants. Understanding the estuarine circulation system is necessary to solve such problems. The salt transport analysis provides hydrodynamic processes about material circulation in the estuary. In this study, to understand the mechanisms of salt transport, a three-dimensional hydrodynamic model was applied in the hyper-tidal estuary system, Yeomha Channel, Gyeonggi Bay. The simulation period of the model was a total of 245 days (January 20 to September 20, 2020), including the dry and wet seasons. The model results for the temporal variation of tide, current velocity, and salinity were validated by comparing them with the observed in-situ data. The salt transport (FS) was calculated in three cross-sections of the Yeomha Channel and was decomposed into three components (QfS0: advective salt transport; FE: steady shear dispersion; FT: tidal oscillatory salt transport). During the dry season with strong tidal forcing, the salt transport patterns were mainly dominated by QfS0. During the wet season with large river discharge, the salt transport patterns were determined by the balance between QfS0, FE, and FT. The long-period tidal constituents (MSf and Mm) were the main mechanisms causing QfS0 with the spring-neap variation during the dry season. The tidal trapping effect, caused by the phase difference of less than 90° between tidal current and salinity, generated landward FT in the dry and wet seasons. In addition, the high river discharge during the wet season decreased the phase difference between tidal current and salinity to less than 70°, resulting in a much strong landward FT. This study suggests that the long-period tidal constituents and tidal trapping effect are unique characteristics that contribute to material circulation in the hyper-tidal estuary.
Modeling the waveforms of induced seismicity sequences with application to Utah FORGE
Authors: Ermert Laura , Lanza Federica , Ciardo Federico , Shi Peidong , Afanasiev Michael , Wiemer Stefan
Published: February 2023

We present a modeling workbench for generating hours-long synthetic sequences of induced seismic events. As input, this tool takes observed or synthetic catalogs of induced seismicity including the location, seismic moment and source mechanism of the induced events. It outputs synthetic seismic waveform recordings with added noise.The purpose of this tool is two-fold: First, it serves to generate synthetic test data that can be used to train detection and location algorithms for induced seismicity monitoring, and to test their efficacy. Monitoring induced seismicity is a key task for the risk management of enhanced geothermal systems, but the relative scarcity of manually labeled data hampers rigorous testing of newly developed algorithms. We intend to partially close the gap in labeled data with synthetics, which can furthermore be used to enhance training data sets for deep learning approaches.Second, the tool serves as an extension to physics-based models of induced seismicity in geothermal reservoirs, such as hydro-mechanical models, providing an efficient way of turning their induced event clouds into seismic “recordings”.The workflow is based on the spectral-element solver Salvus and on Python, and relies on source-receiver reciprocity to decrease computational cost for large sets of induced events. As first application site, we chose the Utah Frontier Observatory for Research in Geothermal Energy – FORGE. This first application comprises a realistic digital representation of the reservoir and its surroundings, including topography, geologic structure and crustal scattering. We will show exemplary synthetic induced seismicity sequences based on an observed catalog from the 2022 stimulation at the Utah FORGE, as well as on a hydro-mechanically modeled synthetic catalog. The output waveform sequences are to be publicly shared for benchmarking monitoring workflows for induced events, in an effort to contribute to the de-risking of enhanced geothermal systems.
Seismological Monitoring of Calving Events in Greenland: A Machine Learning Approach
Authors: Pirot Emilie , Hibert Clément , Mangeney Anne
Published: February 2023

Greenland and other polar regions are highly sensitive to global warming. The impact of climate change on Greenland's glaciers can be seen through an increase in calving events. To better understand this impact, it is important to quantify and document calving activity. However, direct observations are difficult to perform repeatedly over long periods of time due to the hostile climatic conditions, the lack of human witnesses and of the possibility to install in-situ sensors in these remote areas.With the installation of a regional seismological network in Greenland in the 2000’ ,and the densification of the one in north-eastern Canada, seismic signals caused by large volume calving events, known as glacial earthquakes, were recorded at distances of hundreds of km from the source. These signals have a wide range of frequencies, making it hard to distinguish them from tectonic events, anthropogenic noise, and other natural noise. Using two catalogs of known events - one of 444 glacial earthquakes that occurred between 1993 and 2013, and one for 400 earthquakes that occurred during the same time period selected from USGC - we trained and tested a detection algorithm based on the STA/LTA method to extract event signals from continuous data. We then trained a supervised machine learning algorithm (Random Forest) to automatically classify these signals into two different classes : glacial earthquakes and earthquakes, with a probability of belonging to each class.With a workflow designed to limit the false alarm rate based on the probability scores of each events, we finally analyzed over 800 days of data from the Greenland regional seismic network and identified almost 1500 new glacial earthquake events using the trained machine learning model. Our detection methods makes it possible to detect four times more ice-quake than the original catalogue.
Investigating the R&D-CO2 nexus in the international trade
Authors: Costantini Lorenzo , Laio Francesco , Ridolfi Luca , Sciarra Carla
Published: February 2023

Innovation and technological progress are the main drivers of sustainable development and economic growth, and they both play a role in addressing climate change and related actions. These drivers rely on Research and Development (R&D), i.e., the systematic creative work aiming to increase the stock of knowledge and devoted to the creation and development of new products and procedures. Against the existing literature that differently addresses the economic implications of the R&D sector, in this work, we introduce a novel quantification of the R&D content embedded in countries’ export baskets. Considering the current need to understand the dynamics of CO2 emissions and their nexus with the economic aspects, the R&D content in nations’ export baskets is related to the country-specific terrestrial carbon emissions. To this aim, we refer the CO2 emissions embedded in nations' export baskets to the dollars the country at hand exports, defining a country-specific CO2 export intensity; in this way, we can compare economies of different sizes (for example, Germany and Paraguay). Our results show that as countries export products with an increasing R&D content, their CO2 export intensity decreases. Germany, Japan, and the United States are examples of countries exporting high R&D products and having low CO2 export intensity. China stands as an example of elevated CO2 intensity despite having a high R&D content embedded in its export basket. Fuel exporting economies (such as the Russian Federation) and the majority of developing countries have low R&D-oriented export baskets, with high CO2 export intensities. Our work provides a novel perspective of the R&D-CO2 emissions nexus, highlighting the R&D centrality in the green transition and decarbonization process.
Change of tropospheric aerosol over the ocean in the Arctic observed from space
Authors: Mei Linlu , Burrows John , Vountas Marco , Bösch Hartmut
Published: February 2023

Aerosols play a critical role in climate change over the polar regions. The impacts of aerosol on Arctic Amplification is not well understood. In this talk, satellite observations from different instruments are used to understand the spatial and temporal changes of aerosol properties in the troposphere over the ocean in the Arctic in the past four decades. The model simulations are also used to identify the change of aerosol components. The change of Arctic haze due to anthropogenic source is well identified from both satellite observations and model simulations. However, the change of marine aerosol source in the Arctic, especially for the period with strong sea ice melting, is only being observed from satellite observations.
Landforms and chronologies in the southern branch of Kasei Valles, MARS
Authors: Yazıcı Deniz , Yıldırım Cengiz , Görüm Tolga
Published: February 2023

The second-largest valley on Mars is Kasei Valles. This research focuses on the landforms produced by surface processes in the southern branch of Kasei Valles’s midstream. By using cross-cutting relationships, and empirical crater dating of landforms, we constructed a morpho-stratigraphical chronology of the valles. Landforms such as deeply eroded canyons, colluvial fans, landslides, topographic barriers, terraces, and trim lines are typical landforms that have been formed by surface processes.Our geomorphic mapping reveals that the valles were temporarily obstructed by two colluvial fans and a landslide, creating topographical obstacles to impound fluids (e.g lava, mudflow, water). The toe of the alluvial fans and the landslide were eroded by flights of terraces and trim lines, indicating a temporary, water-like liquid presence in the channel of the valles. The surface texture of the terrace surfaces indicates that the terrace staircases were probably created by a water-like fluid that stagnated and fluctuated for a while before the final evacuation.The chronology of these important events indicates that colluvial fans were deposited in two temporal clusters. The first colluvial fan generation was formed in the Early Amazonian period (1.74-1.14 Ga), and the second colluvial fan generation was formed in the Late-Middle Amazonian period (307 Ma). The landslide is significantly younger and is estimated to have formed 122 Ma ago. The floor of the valles’s channel is covered by platy-textured material, which was formed 90 Ma ago as lavas or mudflows, which is the youngest studied geomorphologic feature. The age of the landslide and valles’s floor help us to constrain the timing of erosional processes responsible for the flights of terraces and trimlines, which stretch along approximately 60 km from up to downstream. Accordingly, these features should be formed between 122 Ma and 90 Ma. We believe that the genesis of these features (terraces and trimlines) is associated with a Newtonian fluid (such as water) that ponded behind the colluvial fan dams and the climatic conditions that allow this fluid to stagnate over brief periods of time enough to form terraces and trimlines. 
Fertilizers as batteries and regulators in the global Water-Energy-Food equilibrium
Authors: Kirkmalis George , Sargentis George-Fivos , Ioannidis Romanos , Markantonis David , Iliopoulou Theano , Dimitriadis Panayiotis , Mamasis Nikos , Koutsoyiannis Demetris
Published: February 2023

Fertilizers and especially Nutrient Nitrogen, are high consumers of energy. At present, the energy crisis has a serious effect in the production of fertilizers. As the world is seeking to smooth the curves of energy production, especially by renewable energy installations, the use of potential energy surplus in fertilizers’ production could be an alternative practice. Fertilizers can be utilized for the cultivation of energy crops or food (which also has an energy equivalent). In this work, we attempt to evaluate the potential of the integration of fertilizers in the energy production both for energy recovery and for the avoidance of possible failures by the deficit of fertilizers in the global Water-Energy-Food equilibrium. 