bluuebunny/crossref_metadata_2025 huggingface dataset:
DestinE Core Service Platform Framework
Authors: Sanz-Morère Inés , Hintze Kathrin
Published: February 2023

Destination Earth (DestinE) Initiative is a programme of the European Commission’s DG-CNECT directorate for developing and exploiting a highly accurate digital model of the Earth, with the objectives of monitoring and predicting the interactions between natural phenomena and human activities. This initiative will support the European Commission to achieve the sustainable development objectives and will contribute to the European Green Deal and Digital Strategy. Along with the two entrusted entities ECMWF and EUMETSAT, ESA contributes in DestinE development and implementation. Concretely, ESA is responsible of developing the platform serving as single access point to users to DestinE ecosystem. DestinE Core Service Platform (DESP) integrates and operates an open ecosystem of services (also referred to as DESP Framework) to support DestinE-data exploitation and information sharing for the benefit of DestinE users and Third-Party entities. The industrial activity presented here corresponds to the starting point for DESP development. It includes the setup and definition of DESP Framework, as well as the implementation of key essential services such as user identification, authentication, and authorization service; infrastructure as a service with storage, network, and CPU/GPU capabilities; data access and retrieval service, in particular from the DestinE Data Lake operated by EUMETSAT, as it is the backbone for the data generated by ECMWF’s Digital Twin Engine; data traceability and harmonization services; basic software suite service for local data exploitation; data and software catalogue services; and 2D/3D data visualization service.
IODP 302: Dating 'Zebra'; was the Lomonosov Ridge a central Arctic Ocean Island in the Oligocene?
Authors: Brinkhuis Henk , Sangiorgi Francesca , Wubben Evi , O'Regan Matt
Published: February 2023

Some fifteen years ago, the pioneering Arctic IODP Expedition 302 (ACEX) drilled, and partly recovered Cenozoic sedimentary successions at the Lomonosov Ridge (LR) close to the North Pole. Of the few intervals recovered, one was regarded to likely encompass the Paleogene-Neogene (P/N) transition. On board and follow up marine palynological (mainly dinoflagellate cyst) studies indicate that within this P/N section, a hiatus lasting ~ 25 Myr likely separates the top of the recovered Paleogene (dated ~44 Ma, mid Eocene) from the locally recovered base of the Neogene (likely dated ~18 Ma, mid Early Miocene). The hiatus is represented by the boundary between local lithological subunits 1/6 and 1/5. Unit 1/5 is informally often referred to as the “Zebra unit”, owing to its characteristic (cross bedded) black/white colored alternations of silty clays. Palynological and elemental and organic geochemical studies of subunits 1/6 and 1/5 supported the inference of a major hiatus, as the proxies show a sharp change at the subunit boundary, although the reconstructed paleoenvironments of both subunits indicate marginal marine, restricted conditions. This aspect on its own already represents a challenge for geophysical models, which placed the LR at deeper waters at the P/N boundary. A key finding in the “Zebra unit” is a massive occurrence of representatives of a – back then - unknown dinoflagellate cyst genus, later formally described as Arcticacysta. Because of its morphology, akin to typical Neogene dinocyst taxa, it was postulated that the Zebra interval was early Neogene in age, confirming the existence of a major hiatus. However, successive Rhenium‐Osmium (Re‐Os) isochron ages and complementary Os‐isotope measurements from subunits 1/6 and 1/5 led to postulate that the P/N transition was in essence complete, albeit extremely condensed. This data hence challenged the presence of a major hiatus and depicted a very different geological evolution of the LR. Here we introduce new findings from the lower to mid-Miocene sediments retrieved from the Pennell Basin during IODP Expedition 374 (Ross Sea, Antarctica) in 2018. These now constitute the second known record containing specimens of Arcticacysta. Importantly, these findings now confirm the initial age assignment of the Arctic “Zebra Unit” to the early Miocene and provide decisive evidence for a large hiatus characterizing the P/N transition on the central Lomonosov Ridge. An important corollary is that the central Lomonosov Ridge was likely subaerial or ultra-shallow marine by the end of Oligocene, leading to a totally new perspective of its Cenozoic history.
LGM ice extent and deglaciation history in the Gurktal and Lavantal Alps (Eastern European Alps): first constraints from 10Be surface exposure dating of glacially polished quartz veins
Authors: Hampel Andrea , Wölfler Andreas , Dielforder Armin , Hetzel Ralf , Glotzbach Christoph
Published: February 2023

Compared to the Western European Alps, the ice extent during the Last Glacial Maximum (LGM) and the subsequent deglaciation history of the Eastern Alps east of the Tauern Window remains less well constrained. Also, considerable discrepancies exist between the mapped LGM ice margin (Ehlers and Gibbard, 2011; van Husen, 2004, 2011) and the ice extent predicted by ice-sheet models (Seguinot et al., 2018). Here we present the first 10Be surface exposures ages from two regions east of the Tauern window (Gurktal and Lavantal Alps), which provide constraints on the LGM ice extent and the deglaciation history (Wölfler et al., 2022). Our results show that the deglaciation of the Gurktal Alps occurred between 16-14 ka, which agrees with the predictions from ice-sheet models and implies that the LGM ice cover was greater than mapped. This finding also supported by our analysis of high-resolution DEMs that revealed glacially streamlined ridges and macroscale glacial striations consistent with modelled ice flow directions (Seguinot et al., 2018). In contrast, the 10Be ages from the Lavantal Alps located farther east are either LGM in age or pre-date the LGM, indicating that these regions were ice-free or only partially covered by LGM ice. Based on these results, our future investigations will aim at obtaining more age data from the Eastern Alps to refine the location of the LGM ice margin and the deglaciation history, which is also crucial for climate-evolution and postglacial-rebound models. ReferencesEhlers J, Gibbard PL, Hughes PD (2011) Quaternary glaciations - Extent and chronology. A closer look. Developments in Quaternary Science 15.Seguinot J., Ivy-Ochs S, Jouvet G, Huss M, Funk M, Preusser F. (2018) Modelling last glacial cycle ice dynamics in the Alps. The Cryosphere 12: 3265–3285.van Husen D. (2004) Quaternary glaciations in Austria. In: Quaternary Glaciations: Extent and Chronology Part I: Europe, Ehlers J, Gibbard PL (eds). Elsevier: London: 1–13.van Husen D (2011) Quaternary Glaciations in Austria. In Quaternary Glaciations – Extent and Chronology: A Closer Look, Ehlers J, Gibbard PL, Hughes PD (eds). 15: 15–28.Wölfler A, Hampel A, Dielforder A, Hetzel R, Glotzbach C (2022) LGM ice extent and deglaciation history in the Gurktal and Lavantal Alps (eastern European Alps): first constraints from 10Be surface exposure dating of glacially polished quartz veins, Journal of Quaternary Science  37: 677-687. https:// doi.org/10.1002/jqs.3399
Lowering of groundwater levels and their effect on Water, Sanitation and Hygiene services in the Savelugu District, Northern Region of Ghana
Authors: Acheampong Albert
Published: February 2023

Of all the natural resources available to humankind, water holds a prominent place, particularly because of its importance for human livelihood. Savelugu district in northern Ghana is characterized by unpredictable rainfall patterns with periodic and perennial water shortages. The distance people travel to fetch water and the person-hours spent in search for water affect productivity, economic livelihood, and health and education benefits. Provision of potable water supply to these communities is expected to bring not only health, education benefits but also increase in sanitation and hygiene practices. Static water levels (SWLs) of 19 wells in the study area were collected, analyzed and compared to the initial SWLs measured when the wells were immediately drilled and constructed. The SWL data was subjected to paired samples T-test (with α = 0.05). From the results, there was significant difference in the SWL immediately after drilling and construction (µ = 12.15, σ = 7.50) and SWL after at least 10 years (µ = 17.81, σ = 10.29); t (18) = -3.7, P = 0.002. Lowered groundwater levels were recorded in all wells measured. This can lead to drying up of some of the wells whose difference between the current SWL and well depth is close. There must be strong advocacy, development and implementation of IWRM plans to help address the problem of inadequate WASH in the study area.
Hydrological model calibration in high streamflow extremes climate change studies
Authors: Avesani Diego , Fiori Aldo , Bellin Alberto , Majone Bruno
Published: February 2023

Studies on the effects of climate change on hydrological extremes frequently use hydrological models whose parameters are determined through calibration techniques utilizing observed meteorological data as input force. However, when climate models are applied, this procedure result in a biased evaluation of the probability distribution of high streamflow extremes. As an alternative, we present a methodology called "Hydrological Calibration of eXtremes" (HyCoX), which involves maximizing the likelihood that the predicted and observed high streamflow extremes belong to the same statistical population by means of hydrological model calibrations driven by climate model output.The application of HYPERstreamHS, a distributed hydrological model, to the Adige River watershed (southeastern Alps, Italy), shows that this technique retains statistical coherence and produce accurate quantiles of the yearly maximum streamflow.
Evaluation of three Gap-Filling techniques for daily rainfall data sets: a case study in Portugal
Authors: Fagandini Camilla , Todaro Valeria , Tanda Maria Giovanna , Pereira Joao Lino , Azevedo Leonardo , Zanini Andrea
Published: February 2023

In hydro meteorological temporal datasets, the lack of data is a common problem that can be caused by a variety of factors, including sensor malfunction, errors in measurement, and faults in data acquisition from the operators. Because complete time series are necessary for conducting trustworthy analysis, finding efficient solutions to this issue is crucial. In this work, a gap-filling approach using Kriging-based methods (Ordinary Kriging and Simple Cokriging) is presented and compared to a linear regression approach proposed by the Food and Agriculture Organization (FAO method). The proposed procedure consists of fitting semi-variogram models for each month using the available daily rainfall collected at all stations and averaged for the specific month in the reference period. The advantages are that only 12 monthly semi-variograms have to be built rather than one for each missing day of the dataset and that a greater amount of data at a time can be processed. Then, the Ordinary Kriging and Cokriging are used to estimate the daily precipitation where it is missed using the semi-variograms of the month of interest. The Cokriging method is applied considering the elevation data as the second variable. The FAO approach fills the gaps in rainfall time series by means of a linear relationship between the station that presents missing data and the best correlated station that has data gathered at the gap time. The approaches were compared using daily rainfall data from 60 rain gauges from the Portuguese case study of the InTheMED project for a 30-year reference period (1976-2005). To evaluate the effectiveness of the proposed approaches, one year of data (1985) was removed from some stations; missing precipitation data were estimated using data from the remaining precipitation stations by applying the three procedures. A cross-validation process and an analysis of the error statistics have been considered to determine the accuracy of the estimation for the three gap-filling methods. The outcomes pointed out that the geostatistical approaches outperformed the FAO method in daily estimation. The presented approach performed well in the study area, especially for the Ordinary Kriging, which well-estimated the daily missing data with a low computational effort. However, Cokriging did not significantly improve the estimates.The work presented herein is supported by the PRIMA programme under grant agreement No. 1923, project Innovative and Sustainable Groundwater Management in the Mediterranean (InTheMED). The PRIMA programme is supported by the European Union.
What about human behavior? The case of urbanization and rice in Africa
Authors: De Vos Koen , Janssens Charlotte , Jacobs Liesbet , Campforts Benjamin , Boere Esther , Kozicka Marta , Havlík Petr , Hemerijckx Lisa-Marie , Van Rompaey Anton , Maertens Miet , Govers Gerard
Published: February 2023

Concurrent with an extensive population growth, the African continent has experienced a vast urbanization trend over the last decades. In 2000, around 35% of the population resided in urban areas. By 2020, this share has increased to around 44% and is projected to increase even further by 2050 following the Shared Socioeconomic Pathways (SSP) scenarios. Besides an important effect on local land use through urban expansion, this also affects food systems by shifting dietary patterns away from traditional diets towards imported or convenient goods. This is particularly the case for rice, which is predominantly imported from Southeast Asia, India, or Pakistan, and is gaining in popularity in African urban diets because of the low effort needed for cooking or storage – giving it a strong advantage over other staple crops. This dietary shift will alter trade dynamics, increase the pressure on local resources such as land, water, and fertilizer use, and subsequently also on biodiversity. In studies investigating the influence of urbanization, either the direct effect of urban expansion on land cover or the effects of dietary changes on demands are investigated, but rarely a combination or comparison of both. Particularly in impact studies or applications that focus on the synergy between water, land, and food-related issues, the dimension of human behavior, such as consumer preferences, is often overlooked.In this study, we provide an initial projection of the expected future effects of both sprawl and shifting preferences for rice caused by urbanization on rice availability, land – and input use, rice-specific emissions, and trade dynamics. By combining micro-level data from household surveys stemming from the Living Standards Measurements Study (LSMS) with the partial equilibrium Global Biosphere Management Model (GLOBIOM) at an African scale, we were able to identify the relative contribution of land cover effects stemming directly from urban expansion and indirectly from dietary shifts caused by rural-urban migration and a divergence in income between urban and rural areas.We indicate that while urban expansion only has a limited effect at the continental scale, the omission of any dietary shifts caused by urbanization substantially underestimates projections of African rice demand (by around 8% under an SSP2-scenario). This also results in subsequent underestimations of impacts on land use, trade dynamics, and rice-specific methane emissions. By this, our study exemplifies that consumer preferences are an essential component to understanding urbanization impacts, and that, by extension, human behavior is important to consider in impact and nexus studies.
Digital forest inventory based on UAV imagery
Authors: Dietenberger Steffen , Mueller Marlin M. , Bachmann Felix , Adam Markus , Metz Friederike , Nestler Maximilian , Hese Sören , Thiel Christian
Published: February 2023

Data on forest parameters defining the structure, health and condition of a forest stand is essential for forest management and conservation. The increasing frequency of forest changes, such as those caused by climate change-related drought and heat events, highlight the importance of having a forest database with high spatial and temporal resolution. Automated forest parameter extraction based on unmanned aerial vehicle (UAV) imagery is a cost-effective way to address the need for accurate and up-to-date forest data.The aim of this project is to develop user-friendly tools based on optical data from UAVs that can be applied to accurately and efficiently conduct digital forest inventories. We are using spectral and geometric information from UAV data to create methods for automated derivation of forest parameters such as diameter at breast height (DBH), tree stem positions, individual tree crown delineation, and coarse wood debris. These methods are being designed with the practical needs of potential users from the forestry sector in mind. Different flight configurations, such as nadir and oblique camera angles, as well as different acquisition times, were combined to generate structure from motion (SfM) data products (dense 3D point clouds, orthomosaics and height models) containing both ground and canopy information. For a study site within the Hainich National Park, Germany, we analyzed how leaf-off and leaf-on data can be combined to improve the derivation of stand parameters, such as tree stem positions and individual tree crowns, using point- and raster-based algorithms. Additionally, DBH on an individual tree basis was derived for the same study site using the cast shadows of tree trunks. To do so, a deep learning model was trained to identify stem shadows based on an orthomosaic of only ground points acquired during sunny and leaf-off conditions.
Aggregation Kinetics and Stability of Biodegradable Nanoplastics: Effects of Weathering and Proteins
Authors: Yu Yingxue , Flury Markus , Astner Anton , Hayes Douglas , Zahid Tahsin , Chowdhury Indranil
Published: February 2023

Plastic pollution caused by conventional plastics has promoted the development and application of biodegradable plastics. However, biodegradable plastics do not degrade readily in water, instead, they can generate countless micro- and nanoplastics. Compared to microplastics, nanoplastics are more likely to cause negative impacts to the aquatic environment due to their smaller size. The impacts of biodegradable nanoplastics highly depend on their aggregation behavior and colloidal stability, which still remain unknown. Here, we studied the aggregation kinetics of polybutylene adipate co-terephthalate (PBAT) nanoplastics in both NaCl and CaCl2 solutions before and after artificial weathering. We further studied the effect of proteins on aggregation kinetics with both negatively charged bovine serum albumin (BSA) and positively charged lysozyme (LSZ). We found that divalent cations (Ca2+) destabilized PBAT nanoplastics more aggressively than monovalent cations (Na+); weathering stabilized PBAT nanoplastics profoundly, with no aggregation observed in NaCl nor in CaCl2; both BSA and LSZ promoted the aggregation of pristine PBAT nanoplastics, with LSZ showing more pronounced effect. These results suggest that biodegradable nanoplastics, especially weathered biodegradable nanoplastics, are highly stable in the aquatic environment.
Beyond precipitation: diversity of drivers of high river flows in European near-natural catchments
Authors: Lam'barki Manal , Li Wantong , Oh Sungmin , Zhan Chunhui , Orth Rene
Published: February 2023

High streamflow in rivers can lead to flooding, which may have severe impacts on economy, society and ecosystems. Therefore it is imperative to understand their underlying physical mechanisms. Previous research has illustrated the relevance of several hydrological drivers, such as precipitation, snowmelt and soil moisture. However, the relative importance of these drivers compared with each other is unclear. Moreover, the role of vegetation-related drivers is not well studied. In this study, we focus on high river flows and consider a comprehensive set of potential drivers and analyze their relative importance. This is done with streamflow observations from over 250 near-natural catchments located across Europe during 1984–2007, which are matched with driver data from various observation-based sources. Not surprisingly, we find that precipitation is the most relevant driver of high river flows in most catchments. In addition, and more interestingly, we show that next to precipitation a diversity of other drivers is relevant for high flows, including shallow soil moisture, deep soil moisture, snowmelt, evapotranspiration and leaf area index. These non-precipitation drivers tend to be even more relevant for more extreme high flows. The relative importance of most considered drivers is similar across daily, weekly and monthly time scales. The spatial patterns of the relevance of precipitation, snowmelt and soil moisture for supporting high river flows are controlled by vegetation types and terrain characteristics, while climate and basin area are less important. By analyzing a comprehensive selection of drivers of high river flow in a powerful framework which accounts for co-linearities between drivers, this study advances the understanding of flood generation processes and informs respective model development.
Source-Characterisation of two moderate-sized earthquakes in Nepal employing detailed Moment Tensor Analysis
Authors: Mahto Pooja , Gupta Subhash Chandra
Published: February 2023

Two moderate-sized earthquakes occurred recently in Nepal on 8th November 2022 (Mw=6.1) and on 12th November 2022 (Mw=6.0). The location of these earthquakes falls at 384km and 329km respectively NW of the 25th April 2015 Gorkha earthquake. Both these earthquakes have been studied to understand the source rupture process employing Moment Tensor analysis by estimating the focal mechanism, and source parameters and relocating their hypocentral parameters using their regional waveforms recorded by the 18-stations broadband seismograph network deployed around Tehri dam in the Garhwal Himalaya Uttarakhand.The epicentral distance of all the stations was less than 10◦. We employ the Moment Tensor Inversion approach to invert the broadband waveforms for the mechanism and depths and assume a one-dimensional velocity model developed for the adjacent Himalayan Region. Moment tensor solutions of the events were calculated along with the simultaneous calculation of the centroid position. Joint analysis of the hypocenter position, centroid position, and nodal planes produced clear outlines of Himalayan Fault lines. The epicenter of these earthquakes is located south of the MCT.The obtained source mechanisms are consistent with those reported in the USGS centroid moment tensor (CMT) and NEIC solutions. We evaluated the performance of waveform inversion with just two broadband stations, and the result seems extremely reliable.Inversion results indicate that the focal mechanism of the 8th Nov 2022 earthquake is a thrust fault type, and the obtained strike (283◦), dip (43◦), and rake (83◦) from the Present study are in accordance with CMT results of the USGS (strike (286◦), dip (58◦), and rake (97◦)) and NEIC (strike (285◦), dip (37◦), and rake (82◦)). The seismic moment is 1.583e+19 and the obtained DC% is 93% hence, the mechanism is considered to be Double-Couple. The identification of the source parameters is significant to the investigation of seismic hazards in this region.
Does the spatial variability of the rainfall events affect the efficacy of the hydrological models?
Authors: Indhu Dasari , Vema Vamsi Krishna
Published: February 2023

The major socioeconomic issue affecting the nation's economy is flooding. The use of hydrologic models to predict floods has been the subject of numerous well-founded research, but little is still known about how spatial variability of rainfall affects the flood modeling. The purpose of this study is to comprehend, using the spatial variability index, how rainfall spatial variability affects flood characteristics and its importance in the selection of the hydrological models. The spatial variability index classifies the rainfall events into spatially homogenous (Class A) or spatially varying (Class B) by analyzing the spatial variability of rainfall and catchment properties. Further in this study, both lumped and distributed models have been set-up to understand whether the segregation of events prior to the flood modeling improves the model efficiency or not. Both the models were calibrated separately for the Class A and Class B events. The results shown that Class A events performed better in the lumped model with percentage error in peak flow (PEPF) of 18.45% and 20.32% in calibration and validation respectively. Whereas, the Class B events performance was better in the distributed model with PEPF of 11.5% and 15.85% in calibration and validation. These results were compared against the model calibrated using the traditional method, i.e. without segregating the events. The results show that performance of the lumped model is deteriorated. Similarly, distributed model performance was better when the class B events are separated instead of the combined events. Therefore, segregation of the rainfall events prior to the flood modeling helps in improving the model selection and its performance, which also reduces the assumptions in the model selection.
Calibration of an optical methane clumped isotope thermometer
Authors: Prokhorov Ivan , Tuzson Béla , Kueter Nico , Sivan Malavika , Popa Maria Elena , Röckmann Thomas , Emmenegger Lukas , Bernasconi Stefano M. , Mohn Joachim
Published: February 2023

Methane clumped isotope thermometry relies on accurate measurements of relative abundances of the doubly-substituted isotopologues 12CH2D2 and 13CH3D. Calibration of the thermometer requires, regardless of the applied technique, i.e., laser absorption spectroscopy or high-resolution mass spectrometry, routine preparation of thermally re-equilibrated samples spanning the temperature and bulk isotopic composition (δ13C-, δD-CH4) range of the target applications.Here we present a practical method for methane isotopologue re-equilibration over activated γ-Al2O3. We demonstrate complete and reproducible re-equilibration of clumped isotope signatures with minimal alteration of the bulk isotope composition, almost complete sample recovery, and no detectable formation of decomposition products. Samples spanning a range in δD-CH4 of 100 ‰ were equilibrated between 100 °C and 500 °C and used to calibrate a high-resolution quantum cascade laser absorption spectrometer. In addition, we report on a comparison between the spectroscopic measurements carried out at Empa and an independently calibrated high-resolution mass spectrometric technique using a Thermo MAT253 Ultra at IMAU, Utrecht University.This study is supported by the European Commission under the Horizon 2020 – Research and Innovation Framework Programme, H2020-INFRAIA-2020-1 (grant no. 101008004) and the Swiss National Science Foundation project no. 200021_200977.
Divergent changes in particulate and mineral-associated organic carbon upon permafrost thaw
Authors: Yang Yuanhe , Liu Futing
Published: February 2023

Permafrost thaw can stimulate microbial decomposition and induce soil carbon (C) loss, potentially triggering a positive C-climate feedback. However, earlier observations have concentrated on bulk soil C dynamics upon permafrost thaw, with limited evidence involving soil C fractions. Here, we explore how the functionally distinct fractions, including particulate and mineral-associated organic C (POC and MAOC) as well as iron-bound organic C (OC-Fe), respond to permafrost thaw using systematic measurements derived from one permafrost thaw sequence and five additional thermokarst-impacted sites on the Tibetan Plateau. We find that topsoil POC content substantially decreases, while MAOC content remains stable and OC-Fe accumulates due to the enriched Fe oxides after permafrost thaw. Moreover, the proportion of MAOC and OC-Fe increases along the thaw sequence and at most of the thermokarst-impacted sites. The relatively enriched stable soil C fractions would alleviate microbial decomposition and weaken its feedback to climate warming over long-term thermokarst development.
Sublimation-driven formation of recent mass flows on Mars: experimental tests in low-pressure environments
Authors: de Haas Tjalling , Roelofs Lonneke , Conway Susan , McElwaine Jim , Merrison Jon , Patel Manish , Sylvest Matthew
Published: February 2023

Martian gullies are kilometre-scale landforms consisting of an alcove, channel and depositional fan. They are among the youngest landforms that may have formed by liquid water and are active today. Understanding their formation is thus critical for resolving Mars’ most recent climatic history and potential to sustain life. Gullies on Mars have been hypothesized to have formed by either the action of liquid water and brines or the action of sublimating carbon-dioxide (CO2) ice. They strongly resemble terrestrial systems formed by aqueous debris flows, having similar sedimentology, morphology, and morphometry. Yet, new deposits have formed within multiple gullies across Mars over the past decade, and we cannot reconcile these flows with the low availability of atmospheric water and the triple point of water under present martian conditions. These flows do, however, occur in winter when temperatures are below the CO2 condensation point, and CO2-ice has been observed in many gullies during time of activity. But can CO2 sublimation support and fluidize mass flow on Mars and form deposits similar to terrestrial debris flows? Here, I present novel experiments where we operate small-scale mass-flow flumes inside Mars chambers at Aarhus University (Denmark) and the Open University (UK). In these chambers Martian atmospheric conditions can be simulated, which is crucial for fluidization of mass flows since volume expansion, and therefore gas flow rate, by CO2-ice sublimation is much larger under the low atmospheric pressure of Mars (8 mbar) than under the atmospheric pressure of Earth (1000 mbar). These experiments reveal that CO2 sublimation under martian atmospheric conditions can fluidize mass flows by generating elevated pore pressures reducing intergranular friction, resulting in lobate deposits with levees, as observed in martian gullies. These findings show that CO2-sublimation processes can explain our observations in active Martian gully systems today, which has far-reaching implications for the search for potential liquid water on Mars as well as the interpretation of planetary landforms on other planetary bodies. In particular, they show that on planetary bodies unlike Earth, landforms may be created that look similar to those found on Earth but are actually produced by disparate and so-far unknown processes.
Overview of ambient ice nucleation measurements from 1949 – 2
Authors: Welti André , Thomson Erik S. , Schrod Jann , Ickes Luisa , David Robert O. , Dong Zeyao , Kanji Zamin A.
Published: February 2023

We report on the addition of 50 years of literature data to the Ice Nucleation DataBase (INDB) created for the EU FP7 BACCHUS project (https://www.bacchus-env.eu/in/). The database is intended to become a tool for the Ice Nucleation community to facilitate finding ice nucleating particle (INP) concentration data collected at specific locations and times. The INDB can be used for comparison reviews, to investigate temporal changes in INP concentrations, identify regions of interest, to inform the planning of future observations, and to facilitate data provision for modelling studies. Worldwide data from more than 170 publications between 1949 to 2000 were digitised and added to the INDB, and more than 130 additional publications have been identified and will be utilized to extend the compilation into 2020. Here we provide an overview of the digitised historical datasets, the times, locations, and experimental conditions under which INP were measured. Exemplary insights from the INDB are discussed by comparing ambient temperature spectra pre and post 1970 in different geographic regions.
Transformation of Cartesian to geodetic coordinates on a triaxial ellipsoid using approximations
Authors: Tsafaras Anastasios , Panou Georgios
Published: February 2023

In the last decade, several numerical methods have been presented that transform Cartesian to geodetic coordinates on a triaxial ellipsoid. In this work, a new method for this transformation is presented. The method is based on ellipsoidal coordinates. To begin with, the Cartesian coordinates of a point are transformed to the respective ellipsoidal through closed analytical formulae. Following, the ellipsoidal coordinates referred to the referenced ellipsoid, approximated by those referred to the confocal ellipsoid passed through the given point. Then, the ellipsoidal coordinates are corrected by iterative and non-iterative formulae which are derived and thoroughly analyzed. After the successive approximations, the ellipsoidal coordinates are used for the computation of the foot point and hence of the geodetic coordinates by well-known formulae. The new method is validated by numerical experiments using an extensive set of points for different ellipsoids.
Gully and cliff erosion feature detection in the Wairoa catchment in Hawke’s Bay, New Zealand
Authors: Abad Lorena , Hölbling Daniel , Smith Hugh , Neverman Andrew , Betts Harley , Spiekermann Raphael
Published: February 2023

Gullies and cliff erosion are significant indicators of land degradation. Knowledge of the spatial distribution and dimensions of these erosion features is needed to effectively quantify sediment budgets and to implement erosion mitigation measures. Expert delineation can help identify features at a local sale, however, mapping larger extents becomes time consuming. Object detection techniques based on aerial photographs and LiDAR elevation data can improve the automated delineation of such features. In this study, we tested a region-based convolutional neural network (Mask-RCNN) deep learning approach to identify gully and cliff features. An expert-based delineation of gully and cliff features was performed in the Wairoa catchment in Hawke’s Bay, New Zealand based on aerial photographs obtained between 2017 and 2020. These delineations served as reference data to create labelled chips for training deep learning models. Several terrain derivatives from the LiDAR digital elevation model (DEM), including slope, hillshade, slope length and steepness (LS) factor, and terrain ruggedness index, were computed. The terrain derivatives and spectral bands (R-G-B-NIR) from the aerial photographs were used to train deep learning models based on different band combinations. Despite achieving high accuracy (average precision score above 85%) during training, transferring the models to validation areas resulted in low detection rates, with a large number of false negatives. However, the correctly detected erosion features correspond very well to the reference data delineations, even achieving good results for the differentiation between gullies and cliffs. A closer inspection of the false positive features suggests that the reference data could be incomplete. Our study shows that deep learning has a high potential for automated gully and cliff mapping, but further improvement of the model transferability is needed. A combination of automated and expert-based delineation would potentially result in reliable and efficient erosion feature detection.
Oil smoke plumes as seen through MODIS and CALIPSO
Authors: Mereuta Alexandru , Ajtai Nicolae , Radovici Andrei , Botezan Camelia , Stefanie Horatiu , Camarasan Horia , Costin Dan , Ozunu Alexandru
Published: February 2023

The main focus of this study is in the analysis and identification of a large number of petrochemical smoke plumes from data records spanning over a decade. The events presented in this study where focused on aerosol resulting from major industrial accidents involving offshore oil rigs, oil tank depots and onshore oil wells. The method is based on a synergistic approach of retrieving aerosol optical and microphysical properties using satellite remote sensing and sun photometer data. Data and instruments used in this study include the Moderate Resolution Imaging Spectroradiometer (MODIS), the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) and Aerosol Robotic Network (AERONET) aerosol retrievals. The study also highlighted the inherit limitation of each individual algorithm, thus depicting the importance of further work on aerosol optical depth (AOD) retrievals from major oil smoke plumes. Results show a wide range of values in part due to the varying magnitude of each event in particular. Based on these results we believe that the AOD from the MODIS instruments show lower than expected values. The CALIPSO retrievals where heavily dependent on the type of lidar solutions showing a large degree of discrepancy between constrained and unconstrained retrievals. Unconstrained solutions were attributed to oil smoke plumes identified as part of a larger local aerosol layer. Conversely, lofted smoke was treated as opaque aerosol layers and the measured lidar solutions showed large values and uncertainty. The MODIS retrieval algorithms over land could not successfully retrieve aerosol properties for petrochemical smoke plumes, thus only the ocean algorithm was used for data analysis. When comparing to other studies that utilized ground-based retrievals, the Ångström exponent (AE) and effective radius (Reff) values seem to be in good agreeance. The measured lidar ratios (LR) and particulate depolarization ratios (PDR) seem to indicate higher values similar to values in the upper ranges of biomass burning smoke. We conclude that further work, utilizing remote sensing ground based systems, is needed to properly assess aerosols properties stemming from oil smoke plumes. These results also show how important a synergic approach is for a complete understanding of such phenomena.
Nonlinearity of the equation of state effects dynamics of nonlinear internal waves in late winter lakes
Authors: Stastna Marek
Published: February 2023

In late winter many lakes are iced over, and hence remain cut off from the mechanical forcing due to wind.  At the same time, strong radiative forcing modifies the inverse stratification associated with wintertime conditions.  The inverse stratification occurs due to the fact that freshwater has a temperature of maximum density (around 4 degrees Centigrade) and the equation state of freshwater is thus nonlinear.  In this talk I will demonstrate that this nonlinearity has a profound influence on the characteristics of nonlinear internal solitary-like waves in the cold water regime.  In particular, predcitions of waves made using a piecewise linear density profile yield waves with the opposite polarity to those calculated using temperature profiles and the full nonlinear equation of state.  I will present results based on the Dubreil-Jacotin Long theory, but similar conclusions can be made based on weakly nonlinear (KdV) theory.  Time permitting I will discuss implications of these results for shoaling.
Microplastic Interaction with Soil Water - Visualization and Quantification with Neutron and X-ray Imaging
Authors: Cramer Andreas , Benard Pascal , Anders Kaestner , Zarebanadkouki Mohsen , Carminati Andrea
Published: February 2023

Soil is considered the largest sink of microplastics (MP) in terrestrial ecosystems. Among the expected effects of MP as hydrophobic surface addition is the likelihood that MP enhances soil water repellency. So, crucial for MP fate in soils is the interaction between MP and water. If MP is translocated by water flow and, vice versa, MP impacts water flow, to what extent? Water flow on the pore scale will be impacted with feedbacks on transport and retention of MP. However, we don’t know the extent of and conditions under which MP are transported through porous media and, if deposited, how they interplay with soil water dynamics. We hypothesize that: (i) isolated MP are displaced and translocated by air-water interfaces and (ii) local accumulation of MP is facilitated by bypassing water flow. To approach this question, neutron and x-ray imaging of MP and water in soils was utilized.Dual neutron and x-ray imaging at the beamlines ICON (Paul-Scherrer-Institute) during repeated wetting-drying cycles was applied to trace MP-water interactions in aluminum cylinders filled with sand (0.7-1.2 mm) and MP (PET, 20-75 µm) in gravimetric contents of 0.35, 1.05 and 2.10%. The contents refer to static contact angle estimations of the mixtures resembling < 90°, 90° and > 90°. First, simultaneous neutron and x-ray tomography captured the initial dry MP configuration in samples. Subsequently, neutron radiographies of deuterated water flow through the sample of 1 ml min-1 were recorded for 200s. After drying, repeated tomography gave insights into MP translocation.Neutron and x-ray imaging results showed that regions of major MP content are water repellent. Water flow bypasses and MP is mainly retained. Resultant air entrapments lead to reduced water contents. In regions of minor MP content water can infiltrate. Here, the air-water interface collects isolated MP and shifts their distribution towards an enhanced accumulation.Extrapolation of these results to natural soil systems suggests that vertical transport of MP can be limited especially at hotspots of high MP contents. Water bypasses here. This might limit the water dependent degradation processes of MP due to reductions in hydrolysis, coating and colonization by microorganisms even elongating the process of natural attenuation.
On the potential of mapping sea level anomalies from Copernicus Marine Service with Random Forest Regression
Authors: Passaro Marcello , Juhl Marie-Christin
Published: February 2023

The sea level observations from satellite altimetry are characterised by a sparse spatial and temporal coverage. For this reason, along-track data are routinely interpolated into daily grids provided by the Copernicus Marine Service. These are strongly smoothed in time and space and are generated using an optimal interpolation routine requiring several pre-processing steps and covariance characterisation.In this study, we assess the potential of Random Forest Regression to estimate daily sea level anomalies. One-year-long records of along-track sea level are used to build a training dataset whose predictors are the neighbouring observations. The validation is based on the comparison against daily averages from tide gauges. The generated dataset is on average 10% more correlated to the tide gauge records than the commonly used product from Copernicus. As an example, four time series estimated from satellite altimetry from this study (ML, blue) and CMEMS (orange) at the closest point to four tide gauges (green) are shown in the attached figure. Also shown as text is the Root Mean Square Error (RMSE) of the altimetry dataset considering the tide gauges as ground-truth. Moreover, improvements in the temporal characterisation of the sea level variability will be shown by means of a coherence analysis to be spread over all subannual periods. While the current Copernicus daily sea level anomalies are more optimised for the detection of spatial mesoscales, we show how the methodology of this study can improve the characterisation of sea level variability, particularly in the coastal zone.Our study fits into the use of Copernicus Marine Service data in the context of pan-European coastal zone monitoring, since this innovative machine-learning based technique is validated along the coast of the North Sea. A publication of this study is in advanced state of review in Ocean Dynamics, a pre-print of the first draft is freely available from https://doi.org/10.48550/arXiv.2207.11962.
How accurate are marine Δ14CDIC modelling approaches?
Authors: Butzin Martin , Köhler Peter , Völker Christoph , Ye Ying , Lohmann Gerrit
Published: February 2023

It has been estimated that Δ14C values of marine dissolved inorganic radiocarbon (Δ14CDIC) are primarily governed by transport and radioactive decay. This implies that Δ14CDIC can be considered as a radioconservative tracer which can be implemented into Earth system models without a full marine carbon cycle model. Here we evaluate the accuracies of the radioconservative modelling approach and of a further modelling approach which considers a different simplified representation of the marine radiocarbon cycle, presenting simulation results obtained with the ocean general circulation model FESOM and the marine biogeochemistry model REcoM. The relative uncertainties between the two simplified and the comprehensive treatments of the marine radiocarbon cycle are less than 5%. Therefore, the simplified Δ14CDIC modelling approaches should be sufficiently accurate for many marine radiocarbon studies. 
Strategies to overcome problems in implementing IoT technologies to access urban environment
Authors: Boulet Anne Karine , Ferreira António , Ribeiro Arlindo , Fonseca Fabio , Fraga Pedro , Mafra Sandra , Custódio Filipe , Silva Fernando , Aguilar Gil , Antunes Mario , Maximiano Marisa , Santos Pedro , Relvão Pedro , Cação Ricardo
Published: February 2023

Cities are complex environments, where a multitude of factors, such solar exposition, the patterns of impervious constructed environment versus the green and brown areas can influence the environmental performance of small areas, producing sharp gradients in small distances. The impacts of in terms of microclimate, hydrology and pollutant transport and deposition.The IoT generation sensors provide a unique opportunity to address the diversity of environmental processes and properties that are of exceptional value for the planning and management of cities. The Agrocity project (AVISO Nº 12/SI/2020 - ANI) aims to develop systems to help in the management of different types of environmental conditions.The technical issues related with the project are as follows:Design and develop sensors to measure the critical environmental parameters, economically accessible sensors and with adequate monitoring capacity and frequency for the urban agriculture environment, also capable of being used in decision-making and optimization processes in an agricultural context professional or as support for the identification of vulnerabilities to natural hazards in a context of climate change;Design and implement a communications network for interoperability between different sources of environmental parameters, sensors or laboratory data, related to critical parameters of agricultural environments, and a central services platform that integrates these data and provides information services, based on models from artificial intelligence, to various stakeholders, for example farmers or bodies such as civil protection;Develop a central system to process environmental parameters from machine learning models and provide descriptive and predictive information through an Internet service (Webserver) and application (APPs) for smartphones, developed within the scope of the project, thus allowing access to stakeholders to the platform in real time.
Measurements of PG during rain, hail, snow and lightning
Authors: Kourtidis Konstantinos , Misios Stergios , Karagioras Athanassios , Kosmadakis Ioannis
Published: February 2023

We present an analysis of the evolution of PG during the course of rain, hail and snow events at the Xanthi site, N. Greece. In particular, using data from eight rain events in 2021, four hail events in the period 2018-2021 and four snow events during the same period, we examine how the PG frequency distribution changes during the progression of these events and discuss potential implications for the charge of the hydrometeors and the clouds that produce them. We also present some first results from measurements of PG and lightning at the high altitude (2340 m ASL) site of Helmos Observatory, Peloponnese, Greece.