bluuebunny/crossref_metadata_2025 huggingface dataset:
Fascines for riverbank stabilization : structural failure processes and design suggestions from physical modelling
Authors: Leblois Solange , Piton Guillaume , Recking Alain , Evette André
Published: February 2023

Willow fascine is the soil bioengineering technique for riverbank stabilization the most frequently used in France. Made up of bundles of living branches fixed between stakes, the fascine presents various possible configurations, adaptable to each site. The structure, with high theoretical resistance, is implemented at the bottom of the riverbank joining the riverbed and the riverbank, which makes it subject to strong constraints. Terrain return of experience showed that 22 % of the fascines did not start or did not stand after few years. Punctual observations in the field do not give the possibility to understand the whole process behind fascines structural failure nor to test various fascine configurations over a short period of time. The study based on physical modelling (scale 1:25) describes how riverbanks with fascines are destabilized and develops which fascine design could better stand. The techniques are replicated on the extrados of three meanders created in the flume. Each bank protection technique undergoes the same flood hydrogram. Three various bank toe protection techniques are tested with and without geotextile to protect the rest of the bank. Bank toe without protection is confronted to designs of (i) fascines with one bundle, (ii) fascines with two bundles and (iii) ripraps with the thickness of the two bundles fascine. Bank pressure is measured continuously, the topography is established by photogrammetry before and after each experiment and direct observations are conducted. As first main result, the process of destabilization of riverbanks with fascines could be descripted. Scour holes, naturally occurring at meanders extrados, develop bellow the fascine level of implementation. The bank material initially stocked behind the fascine is than free to fall in the scour hole. The fascine ends up isolated in the river. Without contact to the substrate, the living material cannot start anymore. Moreover, consecutive to the scour holes development, the fascines stakes fall into the river leading to the fascine structural failure. As second result, between the three bank toe protection techniques tested, the fascine with two bundles and geotextile stabilized the best the bank. However, this strong configuration resulted with deeper scour holes at the bottom of the fascine. Finally as third result, with the sediment material used, the water pressure differential between the riverbank and the running water did not enhance any bank erosion. The destabilization of riverbank with fascines is mainly driven by natural morphologic river adjustment. Consequently, the fascine design could be adjusted as follow. (i) The bank slope must be reduced to its maximum to minimize the scour hole. (ii) The fascine must be deeply anchored by the stakes. (iii) The fascine toe, below the level of vegetation start, is preferentially reinforced by extra bundles, wood pieces or riprap, in order to confined the bank material.
Miocene Depocenters and Sediment Supply in the Roer Valley Rift System: Impacts of Tectonics, Eustacy and Climate
Authors: Siebels Alexandra , Ten Veen Johan , Munsterman Dirk , Deckers Jef , Kasse Cornelis , Van Balen Ronald
Published: February 2023

The Miocene sequence in the Roer Valley Rift System consists of alternating shallow marine, coastal and fluvio-deltaic deposits. In this study seismostratigraphy and biostratigraphy are used to determine major unconformities and sediment dispersal patterns. This research is important for future studies related to the geothermal energy potential, and for the improvement of cross-border correlations with the German and Belgian stratigraphic framework. Results show that a depocenter developed in the south-eastern part of the Roer Valley Graben above the Early Miocene Unconformity (EMU) during the Early- and Middle Miocene. Clinoforms are present in a limited area here, but show sediment dispersal from the south-east towards the north-west during periods of progradation. From the late Middle Miocene onwards, larger displacement rates occurred along the major bounding fault zones, i.e. the Peel Boundary Fault Zone, the Feldbiss Fault Zone and the Veldhoven Fault. As a result, the depocenter narrowed and shifted to the central part of the Roer Valley Graben, where accumulation rates increased and larger-scale clinoforms start prograding both towards the west-north-west. This phase coincides with the development of a regional hiatus on the structural highs and forced regression in the south-eastern Roer Valley Graben, caused by a major sea-level fall related to the Middle Miocene Climatic Transition. The effects of tectonics, eustacy and climate resulted in the formation of the Mid-Miocene Unconformity (MMU), which represents a series of events related both to tectonics and sea-level fluctuations, and is therefore expressed differently throughout the Roer Valley Rift System. Sedimentation continued through this period in the deeper parts of the Roer Valley Graben and on the Venlo Block, while an erosional hiatus is evident on the Campine Block and Peel Block. During the latest Miocene, the depocenter migrated to the south-western rim of the Roer Valley Graben, where the youngest Miocene sediments are deposited during a latest Tortonian-Messinian sea level fall that led to the formation of the Late Miocene Unconformity (LMU).
A new high resolution stable isotope record from the North Atlantic Ocean: a detailed insight into the mid-Maastrichtian event
Authors: Fischer Alexa , Friedrich Oliver , Bahr André , Voigt Silke
Published: February 2023

The long-term global cooling trend during the latest Cretaceous was interrupted by an intense global warming episode at ~69 Ma known as the mid-Maastrichtian event (MME). The MME is characterized by two positive 13C excursions with an overall magnitude of 0.6‰ to 1.5‰ separated by a negative inflection. The 13C excursions are accompanied by the extinction of inoceramid bivalves, an abrupt increase in deep-sea and sea-surface temperatures as well as terrestrial mean annual temperatures between 21 and 23 °C at a paleolatitude of ~35° N. Changes in oceanic circulation, particularly a change in thermohaline circulation patterns, have been identified to be one of the main drivers of the MME. Nevertheless, the driving mechanisms, timing, character, and consequences of the circulation change are still up for debate. In this study, a 2 Myr-long time interval of the Mid to Late Maastrichtian has been analyzed at a ~2.5 to 5 kyr-resolution with the aim to improve the understanding of the climatic patterns leading to the MME. For IODP Core U1403 in the North Atlantic (J-Anomaly Ridge), XRF core scanning, wt% CaCO3 analyses, and stable oxygen and carbon isotope records of benthic foraminifera were generated. Bottom-water temperatures were reconstructed through Mg/Ca measurements of the same foraminiferal tests. Preliminary data reveal a warming of North Atlantic deep-sea temperatures by ~2–3°C between ~68.5 and 69 Ma, accompanied by several CaCO3 dissolution events as well as 13C excursions of up to 0.8 ‰. These findings point towards a major perturbation in the global carbon cycle accompanying the overall change in ocean circulation whose causes appear to be more complex than previously thought.
Role and Activities of the GGOS Bureau of Products and Standards
Authors: Angermann Detlef , Gruber Thomas , Gerstl Michael , Heinkelmann Robert , Hugentobler Urs , Sanchez Laura , Steigenberger Peter
Published: February 2023

The Bureau of Products and Standards (BPS) is a key component of the Global Geodetic Observing System (GGOS) of the International Association of Geodesy (IAG). It supports GGOS in its goal to provide consistent geodetic products needed to monitor, map, and understand changes in the Earth’s shape, rotation, and gravity field. In its current structure, the Committees “Contributions to Earth System Modeling” and “Definition of Essential Geodetic Variables” as well as the Working Group “Towards a consistent set of parameters for the definition of a new Geodetic Reference System (GRS)” are associated to the BPS.
This poster contribution presents the role of the BPS and it highlights some of the recent activities, which are focused on the updating of the IERS Conventions, mainly related to Chapter 1 "General definitions and numerical standards", the updating of the BPS inventory of standards and conventions used for the generation of IAG products to incorporate the latest developments in the field, the compilation of user-friendly descriptions of geodetic products published at the GGOS website, and the contribution to GGOS films for specific products. The BPS activities also comprise the interaction with IAG and other entities in the field of standards and conventions, such as the IAG Services, the IERS Conventions Center, the Commission A3 “Fundamental Standards” of the International Astronomical Union (IAU), ISO/TC 211 and the Working Group ``Data Sharing and Development of Geodetic Standards” of the UN-GGIM Subcommittee on Geodesy (SCoG).
Surface temperature variations observed from a thermal infrared camera mounted on a hovering UAV platform
Authors: Elfarkh Jamal , Johansen Kasper , Angulo-Morales Victor , Lopez Camargo Omar , F. McCabe Matthew
Published: February 2023

Land surface temperature (LST) is crucial information that helps to understand and assess the interactions between the surface and the atmosphere. LST is a key parameter used in various applications including studies of irrigation, water use, vegetation health, urban heat island effects, and building insulation. In addition to several satellites that provide periodic images of surface temperature, unmanned aerial vehicle (UAV) platforms have been adapted to obtain higher spatio-temporal resolution thermal infrared (TIR) data. In fact, numerous research studies have investigated the accuracy and the processing method of UAV-based TIR images given its complexity and sensitivity to ambient conditions. However, the surface temperature is characterized by continuous and rapid variation over time, which is difficult to take into consideration in the processing of UAV-based orthomosaics. Here, we quantify this variation and discuss the environmental factors that lead to its amplification. Thermal images were collected over a fixed hovering position during periods of 15-20 min, representing the common duration of UAV flights. At different times of the day, we flew at different altitudes over sand, water, grass and olive trees. Before the quantification of the surface temperature variation, the thermal infrared data were evaluated against field-based measurements using calibrated Apogee sensors. The evaluation showed a significant error in the UAV-based thermal infrared data linked to wind speed, which increased the bias from -1.02 to 3.86 °C for 0.8 to 8.5 m/s winds, respectively. The assessment of the LST values collected over the different surfaces showed a temperature variation while hovering ranging between 1.4 and 5 °C. In addition to wind effects, temperature variations while hovering were strongly linked to solar radiation, specifically radiation fluctuations occurring after sunrise and before sunset. This research provides insights into the LST variation expected for standard UAV flights of 15-20 min under different environmental conditions, which should be taken into account during UAV-based thermal infrared data processing and may help interpret and quantify inconsistencies in UAV-based orthomosaics of LST.
Assessing Arctic low-level clouds and precipitation from above - a radar perspective
Authors: Schirmacher Imke , Crewell Susanne , Lamer Katia , Mech Mario , Wendisch Manfred
Published: February 2023

According to satellite-based estimations, a lot of clouds over the Arctic Ocean occur below2 km. Most information on Arctic low-level clouds come from CloudSat radar measurements.However, CloudSat lacks a complete representation of low-level clouds because the blindzone masks the lowest kilometer and the coarse spatial sampling conceals cloud patterns.Thus, higher resolved observations of cloud characteristics are needed to determine howthe cloud fraction varies close to the ground and how it depends on surface characteristicsand meteorological situation.Our study investigates the low-level hydrometeor fraction of Arctic clouds over the oceanusing airborne remote sensing measurements by the Microwave Radar/radiometer for ArcticClouds (MiRAC) flown on the Polar 5 aircraft. Four campaigns have been conducted in thevicinity of Svalbard during different seasons: ACLOUD, AFLUX, MOSAiC-ACA, and HALO-AC3. We convolute the MiRAC radar reflectivity measurements to adapt the fine MiRAC andcoarse CloudSat resolution. The convoluted measurements are compared with the originalairborne observations over all campaigns to investigate the effects of CloudSat’s spatial res-olution, clutter mask, and sensitivity on the low-level hydrometeor fraction. Measurementsreveal high hydrometeor fractions of up to 60% in the lowest 1.5 km, which CloudSat wouldmiss due to the blind zone. CloudSat would especially underestimate half of the total pre-cipitation. During cold air outbreaks, when rolling cloud structures evolve, CloudSat over-estimates the hydrometeor fraction most. Moreover, CloudSat does not resolve the separatelayers of multilayer clouds but rather merges them because of its coarse vertical resolution.
Organic carbon to clay ratios can help to optimize organic amendment use at the farm level
Authors: Haefele Stephan , Prout Jonah , McGrath Steve , Kirk Guy
Published: February 2023

Realistic targets for soil organic carbon (SOC) concentrations are needed, accounting for differences between soils and land uses, to help farmers manage the SOC across their farms. We assess the use of SOC/clay ratio for this purpose using data from the the National Soil Inventory of England and Wales and (b) two long-term experiments under ley-arable rotations on contrasting soils in the East of England. The results showed that normalising for clay concentration provides a more meaningful separation between land uses than changes in SOC alone. The results suggest realistic long-term targets for SOC/clay in arable, ley grass, permanent grass and woodland soils. Given the wide range of soils and land uses across England and Wales in the datasets used to test these targets, they should apply across similar temperate regions globally, and at national to sub-regional scales. We use these results to outline a strategy for organic amendment management at the farm level, enabling optimal use of this scarce resource.
Hydrodynamic simulations of the flash flood event in July 2021 in the Wesselbach catchment in Germany, and the effects of land use changes
Authors: Tügel Franziska , Eckmann Lizanne , Steffen Lennart , Hinkelmann Reinhard , Paton Eva
Published: February 2023

Flash floods are among the most dangerous natural hazards and the associated risks are likely to increase due to climate change and increased urbanization. Observations of the last decades and projections of the future climate show an increase in the frequency and intensity of heavy rainfalls for many land surfaces. In July 2021, many European countries have been severely affected by large-scale heavy rainfalls. In Germany, the federal states of North Rhine-Westphalia and Rhineland-Palatinate have been particularly affected with at least 180 fatalities, hundreds of injuries, lots of heavily damaged buildings, and extensive infrastructural damages. The modeling of flash floods is essential for effective risk management to produce hazard and risk maps, investigate the effects of land use changes, and plan mitigation measures.This works aims to investigate the flash flood event in the Wesselbach catchment in North Rhine-Westphalia (Germany), which was generated by an extreme, short rainfall event of 118 mm within less than two hours in the late evening of 13th July 2021. The catchment is part of the city of Hagen, and the considered model domain of approximately 3 km² is characterized by steep slopes, a main soil type of silty loam, and a main land use type of forest, with settlements along the main watercourse in the downstream half of the domain. Large portions of coniferous areas in the catchment have exhibited decreasing vitality since 2018, up to complete dead or cleared areas. The in-house robust shallow water model hms++ is used to simulate the flash flood event using the measured rainfall data of a nearby rainfall gauge as input. Spatially distributed Manning’s roughness coefficients are used to account for the different land use types. Infiltration is neglected as the soils in that area show limited infiltration capacity, and the worst-case is considered that the soils are already saturated. Building heights have been included in the digital elevation model.The results include the temporal development of flooding areas, spatial distributions of maximum water depths, and flow velocities in the Wesselbach catchment as well as hydrographs at different cross-sections of the main water course. Furthermore, the effects of forest damage on the discharge behavior and flooding areas will be investigated. Later on, structural mitigation measures will be included in the model to study their effectiveness for different heavy rainfall events.
Dynamics of multi-specie pasturelands under potential climate changes. The Gran Paradiso Park of Italy.
Authors: Morgese Sonia , Casale Francesca , Bocchiola Daniele
Published: February 2023

Climate change’s effects are remarkable on water systems, especially for alpine mountain regions. This study aims to assess the impact of climate change upon productivity of mountain pastures in the Gran Paradiso National Park (GPNP), Italy. For this purpose, some agro-climatic indices were introduced. GPNP dynamics are linked to the complex cryospheric hydrology of Alpine catchment and to the interspecies competition, which are in turn expected to change remarkably under prospective global warming scenarios. The hydrological Poli-Hydro model was used to simulate the cryospheric processes affecting the hydrology of high altitude catchments of the area. The Poli-Pasture model was developed for the simulation of pasture vegetation growth, and completed with adaptation of the CoSMo model, to consider interspecific competition. Two species were chosen for low altitude (elevation lower than 1800 m a.s.l.), e.g. Trifolium Alpinum and Dactylis Glomerata, and two species, Festuca Rubra and Nardus Stricta, for high altitude (elevation greater than 1800 m a.s.l.).Model calibration and validation were performed against LAI (Leaf Index Area) during 2005-2019, using observed values available from satellite imagery.Through four scenarios from the Sixth Assessment Report of IPCC (SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5) applied to six GCM models (CESM2, CMCC, EC-EARTH3, HADGEM3 and MPI-ESM), meteorological data up to the year 2100 were derived. Using such climate projections, future agro-climatic indices, leaf area index and pasture yield were estimated.According to IPCC projections, during growing season, temperature will noticeably increase at the end of the century, especially in high altitude areas, where mountain areas will experience highest temperature eve, with few heat wave days.Due to increasing temperatures, a potential increase in productivity has been found in higher areas (up to 96% more by 2050 and 123% in by 2100, according to SSP5 8.5 scenario) and a lower change in lower elevation areas. The results provide preliminary evidence of potential livestock, and thereby economic development in the valley at higher altitudes than now. Under reduction of precipitation in summer, decrease in water consumption is expected, with possible lack of available water.
Seismic imaging on volcanoes using Machine Learning
Authors: Bean Chris , O'Brien Gareth , Lokmer Ivan
Published: February 2023

Despite advances in seismic instrumentation and seismic network densities, the ability to obtain detailed images of subsurface volcanic structure is still compromised. This leaves large uncertainties in the time evolution and nature of shallow magma emplacement, for example. Ideally it is desirable to see objects at the scale of individual sills, but strong wave scattering in volcanic settings makes this difficult to achieve and tomographic images smooth out objects at this scale. Multiple scattering creates a ‘fog’ through which it is difficult to pick singly scattered (reflected) events of interest. We use a Deep Learning approach to try capture information from this full wavefield and use that to build detailed images. Specifically we employ a Fourier Neural Operator (FNO) to model and invert seismic signals in heterogeneous synthetic volcano models. The FNO is trained using 40,000+ simulations of full wavefield elastic waves propagating through these 2D models. Once trained, the forward FNO network is used to predict elastic wave propagation and is shown to accurately reproduce the seismic wavefield. That is, the FNO can act as a fast and highly efficient forward full wavefield simulator. The FNO is also trained to predict highly heterogeneous velocity models given a set of seismograms. We show that this Deep Learning approach accurately predicts known synthetic velocity models based on surprisingly small sets of input seismograms, capturing details of the velocity structure that would lie outside the ability of current seismic methods in volcano imagery. This offers a potential new approach to imaging in volcanic environments. Although the upfront training cost of 40k simulations is very large, once trained the run times for the FNO are negligible.  
Comparison of LSTM, GraphNN, and IrradPhyDNet based Approaches for High-resolution Solar Irradiance Nowcasting
Authors: Papazek Petrina , Schicker Irene , Gfähler Pascal
Published: February 2023

With fast parallel computing hardware, particularly GPUs, becoming more accessible in the geosciences the now efficiently running deep learning techniques are ready to handle larger amounts of recorded observation and satellite derived data and are able to learn complex structures across time-series. Thus, a suitable deep learning setup is able to generate highly-resolved weather forecasts in real-time and on demand. Forecasts of irradiance and radiation can be challenging in machine learning as they embrace a high degree of diurnal and seasonal variation.Continuously extended PV/solar power production grows into one of our most important fossil-fuel free energy sources. Unlike the just recently emerging PV power observations, solar irradiance offers long time-series from automized weather station networks. Being directly linked to PV outputs, forecasting highly resolved solar irradiance from nowcasting to short-range plays a crucial role in decision support and managing PV.In this study, we investigate the suitability of several deep learning techniques adopted and developed to a set of heterogeneous data sources on selected locations. We compare the forecast results to traditional – however computationally expensive - numerical weather prediction models (NWP) and rapid update cycle models. Relevant input features include 3D-fields from NWP models (e.g.: AROME), satellite data and products (e.g.: CAMS), radiation time series from remote sensing, and observation time time-series (site observations and close sites). The amount of time-series data can be extended by a synthetic data generator, a part of our deep learning framework. Our main models investigated includes a sequence-to-sequence LSTM (long-short-term-memory) model using a climatological background model or NWP for post-processing, a Graph NN model, and an analogs based deep learning method. Furthermore, a novel neural network model based on two other ideas, the IrradianceNet and the PhyDNet, was developed. IrradPhyDNet combines the skills of IrradianceNet and PhyDNet and showed improved performance in comparison to the original models.Results obtained by the developed methods yield, in general, high forecast-skills. For selected case studies of extreme events (e.g. Saharan dust) all novel methods could outperform the traditional methods.  Different combinations of inputs and processing-steps are part of the analysis.
Quartz under stress: Raman calibration and applications to geobarometry of metamorphic inclusions
Authors: Reynard Bruno , Zhong Xin
Published: February 2023

An experimental calibration of the Raman shifts of quartz with pressure up to ~2 GPa and differential stress up to ~0.6 GPa parallel and perpendicular to the c-axis is presented. The position of the 206 cm−1 peak depends only on hydrostatic pressure P, and its pressure dependence is recalibrated with a peak fitting procedure that is more adequate for Raman barometry than previous calibrations. The position of the 128 and 464 cm−1 peaks depends on P and also on differential stress , which can be determined from the position of these two peaks knowing hydrostatic pressure from the position of the 206 cm−1 peak. This calibration provides direct relationships between Raman shifts and stress, with a simple formulation of residual pressure and differential stress assuming uniaxial stress along the c-axis of quartz inclusions. It is tested on data from experimental and natural inclusions. Pressures from the present calibration are similar within uncertainties to those obtained with previous experimental calibration within uncertainties, and experimental inclusions yield residual pressures consistent with synthesis pressure. Inconsistent residual differential stresses are obtained from the 128 and 464 cm−1 peaks on some experimental inclusions, providing a criterion for identifying inclusions under complex stress conditions that are not appropriate for geobarometry. Recent data on natural inclusions show self-consistent differential stress, consistent with the assumption of major stress along symmetry axis of the inclusion crystals and with values expected from elastic models. The average pressure values from the 128 and 464 cm−1 peaks is similar to the residual pressure from the 206 cm−1 peak that depends only on hydrostatic pressure. It can be used to obtain pressure when the 206 cm−1 peak position cannot be used due to interference with host mineral peaks. Using the 128 and 464 cm−1 peaks alone, or averaging either 128 and 206 or 206 and 464 cm−1 peaks can induce systematic bias in the residual pressure determination. Applications of the present results to natural inclusions suggest that combined determination of residual pressure and differential stress may be used both for barometry and thermometry pending further calibration.
Is Central Pacific ENSO on the rise? Insights from the past 300,000 years
Authors: Hess Katharina , Jaeschke Andrea , Friedrich Oliver , Bahr André
Published: February 2023

The El Niño-Southern Oscillation (ENSO), known for exceptional heavy rainfalls, droughts and inundations in the Pacific and Indian Ocean realm, is one of the largest oceanic and atmospheric phenomena on Earth influencing global climate patterns. Over the last decades, a strong warming in the high latitudes of both hemispheres has been observed to coincide with the rise of a third ENSO type — “El Niño/La Niña Modoki”, also called Central Pacific ENSO. During El Niño Modoki (La Niña Modoki) events, sea-surface temperature (SST) is higher (lower) in the central equatorial Pacific, flanked by colder (warmer) SSTs in the western or eastern Pacific, associated with a twin Walker Circulation. The study aims to understand the underlying spatio-temporal dynamics and processes of Central Pacific ENSO and a possible link to anthropogenic impacts from a paleo-perspective to improve the predictability of Central Pacific ENSO variations in the future.

Therefore, high-resolution (c. 1–2 kyr resolution) proxy records of SST variability are generated from marine sediment cores from the western, central, and eastern equatorial Pacific from the Middle-Pleistocene to present. The SST reconstructions are based on Mg/Ca ratios of planktic foraminifers and biomarker (alkenone) analyses.

Based on preliminary and published data, a lower east–west SST gradient and colder SSTs in the central Pacific occurred during warmer periods. La Niña Modoki conditions apparently become more frequent with increasing CO2 conditions pointing at the likelihood that La Niña Modoki conditions will become more prevalent in the near future. Accordingly, an increase in precipitation on both sides of the Pacific realm could be expected.
Vegetation pattern in a natural wetland floodplain is predicted better using river-floodplain inundation extents than standard hydrological variables
Authors: Berezowski Tomasz , Wassen Martin
Published: February 2023

The extent of water from river and floodplain (groundwater, rainfall, and snowmelt) in an inundation is related to ecological processes such as vegetation development. A prominent example of this phenomenon is the Biebrza floodplain, which is a 220km2 natural, temperate zone, fen wetland, with extensive river flooding. The lateral vegetation zonation in this area was related to the flooding frequency and water depth; however, more recent research showed that the extent of the river water zone within the inundation is a better predictor of the vegetation pattern. Despite its significance, the long-term sensitivity of vegetation zonation with respect to changing extent of water zones and climate was not investigated. In this study, we used the Hydraulic Mixing-Cell (HMC) method to simulate the extent of water from rainfall, snowmelt, groundwater discharge, and river flooding. The HMC is implemented in the HydroGeoSphere model, which was set up for the entire 7000 km2 Biebrza catchment. The model was forced using the Twentieth Century Reanalysis data for the period 1881-2015 and using an ensemble of ten EURO-CORDEX simulations for RCP 2.6, 4.5, and 8.5 for the 2006-2099 period. The model output was used to establish vegetation models using three vegetation maps from 1960, 1980, and 2000 and the random forests algorithm. The results show that the vegetation pattern in Biebrza wetlands was predicted with higher accuracy with the water sources zonation predictors from the HMC, whereas the vegetation models using surface water depth and duration or soil moisture, groundwater discharge, and groundwater levels predictors had lower accuracy. Finally, the vegetation was predicted for the entire two centuries period to show that the vegetation change in Biebrza wetlands may occur due to change in water sources’ zonation, which is driven by climate.
Modeling hot-spot of N2 and N2O production in agricultural soils as introduced by liquid organic fertilization
Authors: Grosz Balázs , Dechow Rene , Well Reinhard
Published: February 2023

Prediction of liquid organic fertilizer effects by biogeochemical models on denitrification and associated N2O and N2 fluxes in soils is inappropriate, because previous studies mostly excluded N2, and the calibration of the models without N2 data is inaccurate. Besides, the models mostly homogenize the substrate content of the applied manure with the corresponding substrate pools of the soil, without the consideration of the effects of the liquid manure induced hot-spots in the soil. Therefore, the main goal of the MOFANE Project was to develop a new approach dealing with hot spot effects in manure amended soils. A simple and static model approach (Sommer et al., 2004) was improved and developed for a dynamic model to consider the effect of the manure induced hot-spots in the soils. It contemplates the effect of the application technique of the liquid manure (surface or injected), the ammonium and labile organic carbon content of the manure, the water content and the structure of the soil to calculate the NH3 loss, the N mineralization and O2 consumption of the degradable organic content, the nitrification and the denitrification in the manure-soil hot-spot region. The substrate exchange and flow are calculated based on the water potential difference between the liquid manure and soil. A laboratory experiment was conducted to provide proper input and output data for the model testing.  A sandy (Grosz et al., 2022) and a loamy arable soil were investigated in 10 days laboratory incubations. The temperature was constant 15oC and the water-filled pore space (WFPS) were constant 40% and 60%. The soils were amended with and without artificial slurry in three manure treatments (control, surface-applied, injected). N2O and CO2 fluxes were quantified by gas chromatography. N2 and source-specific N2O flux was quantified by isotope-ratio mass spectrometry. The results of laboratory experiments will be used for testing the model accuracy. Grosz, B., Kemmann, B., Burkart, S., Petersen, S. O., and Well, R.: Understanding the Impact of Liquid Organic Fertilisation and Associated Application Techniques on N2, N2O and CO2 Fluxes from Agricultural Soils, Agriculture, 12, 692, https://doi.org/10.3390/agriculture12050692, 2022.Sommer, S. G., Petersen, S. O., and Møller, H. B.: Algorithms for calculating methane and nitrous oxide emissions from manure management, Nutrient Cycling in Agroecosystems, 69, 143–154, https://doi.org/10.1023/B:FRES.0000029678.25083.fa, 2004. 
Spatio-temporal analysis of extreme hydrological events in a joint framework and its relationship with land-use land-cover change
Authors: Torres Eliana , Corzo Gerald , Solomatine Dimitri
Published: February 2023

Extreme hydrological events have had several economic, ecologic, and social impacts on many regions around the world. Although the impacts of floods and droughts are equally important and severe, they are typically treated as separate phenomena due to their hydrological differences. However, in order to address and mitigate their impacts, it is important to analyse and model the interactions between the spatial and temporal characteristics of the events, not only separately but also in a joint framework. Moreover, understanding and simulating the effects of land-use land-cover changes on extreme events dynamics is crucial to improve the development of land use policies and risk management plans. The Central America Dry Corridor (CADC) is one of the regions in the world with the highest vulnerability to floods and droughts due to its marked precipitation seasonality and climate variability. Land use change is also an important variable in this mainly rural area, in which forest cover has declined rapidly during the last decades, modifying basin runoff and affecting extreme events generation. Therefore, this study proposes a methodology to analyse and represent in a joint framework the spatio-temporal characteristics of CADC’s floods and droughts, and identify their relationship with land-use land-cover change patterns. To achieve this, a hybrid modelling framework that integrates Machine Learning (ML) techniques with a spatially distributed hydrological model is presented. It is expected that the integration of ML techniques increases hydrological model capabilities to accurately simulate the effects of land-use land-cover change on floods and droughts propagation. It is also expected that the hybrid model can be used as a tool to assess the effectiveness of different risk management measures and land use policies in floods and droughts mitigation. 
Climate trends, variability and extremes recorded by water isotopes during the last two millennia
Authors: Werner Martin , Cauquoin Alexandre
Published: February 2023

Stable water isotopes are widely used to reconstruct past temperature and precipitation variations in many regions of the Earth. While the general physical processes of how isotope variations are controlled by temperature and water amounts is well understood, quantifying past isotope changes as a proxy for temperature and precipitation is much more difficult. An explicit simulation of water isotopes in current Earth system models is one possibility to approach this problem.In this study we present new results of a transient fully-coupled simulation of the climate of the last two millennia, using the isotope-enabled model MPI-ESM-wiso. We analyze long-term trends, variability and extremes of the simulated isotope changes in precipitation, compare model results to available data compilations (e.g. PAGES Iso2k) and quantify the relations with associated temperature and hydrological changes. Our analyses show that for many regions of the Earth, the surface warming starting with the beginning of the industrialization period is clearly imprinted in the oxygen-18 isotope signal of precipitation, e.g., over Greenland, North America, and the Atlantic Ocean. However, in some regions recent temperature, precipitation and isotope changes seem to be decoupled, e.g., over West Antarctica, Oceania, and the Indian Ocean. In our presentation, we will discuss this regional varying imprint of the Anthropocene on the water isotope signal in detail. Further analyses focus on changes in isotope variability in different regions over the last two millennia, as well as the possible detection of past climate extremes in different isotope records.
Dynamic hyporheic zone: Impact of non-steady stream flow and moving streambeds on the fate of trace organic contaminants
Authors: Villa Arroyave Maria Alejandra , Spahr Stephanie , Arnon Shai , Lewandowski Jörg
Published: February 2023

The occurrence of trace organic compounds (TrOCs) such as pharmaceuticals and personal care products in aquatic ecosystems has been a growing concern in urban environments in recent decades. Incomplete removal of organic compounds in conventional wastewater treatment along with increasing use of chemicals, especially due to urbanization, increase the contamination of rivers and groundwaters with high loads of TrOCs. Different strategies to combat this type of environmental pollution have been researched, leading to a better understanding of the occurrence and fate of these contaminants. For instance, the natural attenuation of TrOCs by processes occurring in the hyporheic zone has been recognized as an efficient alternative for contaminant removal. However, little is known about the effects of stream flow velocity and bedform celerity on TrOCs removal, although bedform migration is a common process in many natural and urban streams. Our research project evaluates the influence of bedform migration on the fate of sixteen organic contaminants and their transformation products due to dynamic hyporheic zone exchange. Both controlled flume experiments and field measurements in a side channel of the River Erpe in Germany contribute to understanding the effects of dynamic flow conditions on the biotransformation of TrOCs. The knowledge obtained may be applied to enhance water management remediation programs, considering water bodies' ecological and chemical status.Keywords: TrOCs, hyporheic zone, bedform migration, flume experiments, attenuation, biotransformation.
Drivers of large footprints of extreme winds and rainfall and their projected future changes
Authors: Manning Colin , Kendon Elizabeth , Fowler Hayley J. , Catto Jennifer L. , Chan Steven C. , Sansom Philip
Published: February 2023

Extratropical cyclones produce extreme surface wind speeds and heavy rainfall which can individually and jointly influence impacts and potentially produce large aggregate impacts. Within this study, we assess the UKCP 12-member ensemble of local convection-permitting 2.2 km climate projections. We quantify the likelihood of cyclones producing large footprints of both extreme winds and rainfall over the UK in a control (1981-2000) and future (2061-2080, RCP8.5) climate simulation. Following this, we characterise the convective and frontal drivers of wet and windy conditions within cyclones, and identify the characteristics of cyclones, their tracks and interactions with the jet stream that contribute to the occurrence of large, combined footprints in the control and future simulations. The future simulations project an increased probability of extratropical cyclones producing extremely wet and windy conditions in the same storm, as well as an increase in the land area covered by such conditions. In both the control and future simulations, combined wet and windy extremes largely occur close to cold and warm fronts, likely due to the warm conveyor belt which produces heavy rainfall (due its ascent over the frontal boundaries) and high winds (when occurring within a region of tight pressure gradients). Cyclone composites reveal that the largest changes in joint extremes are closely located within the sector of cyclones where we expect to see the warm conveyor belt, suggesting their change arises partly through the response of this shared driver rather than being a simple consequence of increased rainfall due to thermodynamics. In further analysis, we identify favourable conditions and cyclone characteristics that lead to cyclones producing large rainfall and wind footprints over the UK.
Monitoring sudden stratospheric warmings under climate change since 1980 based on reanalysis data verified by radio occultation
Authors: Li Ying , Kirchengast Gottfried , Schwaerz Marc , Yuan Yunbin
Published: February 2023

We developed a new approach to monitor Sudden Stratospheric Warming (SSW) events under climate change since 1980 based on reanalysis data, verified by radio occultation data. We constructed gridded daily-mean temperature anomalies from the input fields at different vertical resolution (basic case full resolution; cross-check with reanalysis at 10 stratospheric standard pressure levels or 10 hPa and 50 hPa level only) and employed the concept of Threshold Exceedance Areas (TEAs), the geographic areas wherein the anomalies exceed predefined thresholds (such as 30 K) to monitor the phenomena.We derived main-phase TEAs, representing combined middle and lower stratospheric warming, to monitor SSWs on a daily sampling basis. Based on the main-phase TEAs, three key metrics, including main-phase duration, area, and strength are estimated and used for the detection and classification of SSW events. An SSW is defined to be detected if the main-phase warming lasts at least 6 days. According to the strength, SSW events are classified into minor, major and extreme. An informative 42 winters’ SSW climatology 1980-2021 was developed, including the three key metrics as well as onset date, maximum-warming-anomaly location and other valuable SSW characterization information.Detection and validation against previous studies underpins that the new method is robust for SSW detection and monitoring and that it can be applied to any quality-assured reanalysis, model, and observational temperature data that cover the polar region and winter timeframes of interest, either using high vertical resolution input data (preferable basic case), coarser standard-pressure-levels resolution or (at least) 10 hPa and 50 hPa pressure level data. Within the 42 winters, 43 SSW events were detected for the basic case, yielding a frequency of about one event per year. In the 1990s, where previous studies showed gaps, we detected several events. Over 95 % of event onset dates occurred in deep winter (Dec-Jan-Feb timeframe; about 50 % in January) and three quarters have their onset location over Northern Eurasia and the adjacent polar ocean.Regarding long-term change, we found a statistically significant increase in the duration of SSW main-phase warmings, by about 5 days over the climate change period from the 1980s to the 2010s, raising the average duration by near 50 % from about 10 to 15 days and inducing an SSW strength increase by about 40 million km2 days, from about 100 to 140 million km2 days. The results are robust (consistent within uncertainties) across using different input data resolution. They can hence be used as a reference for further climate change-related studies and be a valuable basis for studying SSW impacts and links to other weather and climate phenomena, such as changes in polar vortex dynamics and in mid-latitude extreme weather.
Mineral-trapping of greenhouse gases in Arctic glendonites
Authors: van de Schootbrugge Bas , Schobben Martin , Morales Chloe , Polerecky Lubos , Kienhuis Michiel , Nierop Klaas , Peterse Francien , Janssen Nico , He Tianchen , Newton Rob , van Winden Julia , Weijers Johan , Podlaha Olaf , Sluijs Appy , Middelburg Jack
Published: February 2023

Fossil ikaite, preserved as the pseudomorph glendonite, occurs in vast amounts in Jurassic and Cretaceous successions in the high Arctic. Thermodynamics predict that ikaite is only stable at near-freezing temperatures and glendonite is thus widely used as a paleo-indicator of cold climate conditions, conflicting with traditional views of a very warm and equable Mesozoic greenhouse. Here, we show based on a multi-proxy investigation of Jurassic and Cretaceous glendonites from Siberia and Svalbard that this one-dimensional view detracts from their exceedingly complex biogeochemistry. NanoSIMS analyses of a Jurassic glendonite from Siberia produced large C-isotope gradients (> 40‰) over micrometer distances hinting at strong kinetic fractionation that is coupled to the formation of various precipitates, including an inclusion-rich primordial phase with C-isotope values as low as -38‰ that records methane oxidation. In line with previous results from Siberia, all investigated glendonites from the Cretaceous of Svalbard contain methane gas (700 - 2500 ppb/g) with enriched δ13C-CH4 signatures (-44 to -50‰ V-PDB), depleted δ2H--CH4 (-285 to -245‰ V-SMOW), and relatively large proportions of C2-C5 gas. Such values are potentially indicative of thermogenic methane gas sourced from structure II gas hydrates. Organic geochemistry of glendonites from Svalbard shows the presence of abundant hopanes, including bisnorhopanes with a CSIA signature of -41‰, suggesting activity of sulfide oxidizing bacteria possibly also linked to the inclusion of oil droplets. Moreover, exceptionally heavy bulk δ34Scas values of +46.2‰ clearly link marine ikaite formation in deep time to sulfate-driven anaerobic methane oxidation. Marine ikaite formation and preservation is thus a highly complex process, driven by temperature and (bio)chemical processes in the sea floor, complicating its use as a simple paleoclimate proxy. Regardless, glendonite episodically trapped large amounts of greenhouse gases and stored those for hundreds of millions of years, making this authigenic mineral a potential recorder of past carbon cycle perturbations.