bluuebunny/crossref_metadata_2025 huggingface dataset:
Rotation of borehole breakouts by the effect of fractures/faults: observation and numerical model study
Authors: Kang Minzy , Chang Chandong
Published: February 2023

Borehole breakouts, rock compressive failure at the wellbore wall, are one of the most widely utilized stress indicators, providing useful site-scale in situ stress states for a variety of geo-engineering projects. A 1 km deep vertical borehole drilled to study earthquakes in southeast Korea showed borehole breakouts rotated in azimuth at several depths by as much as 35° from the average azimuth, enlarging uncertainty in representative stress orientation. These breakouts developed in a highly fractured tuffaceous rock at a depth range from 840 m to 1000 m and breakout rotation always occurred adjacent to fractures and faults. While breakout rotation adjacent to fractures/faults has often been observed previously, there are several issues that have to be addressed regarding such a rotation, that is, would it be a local perturbation associated with drilling that can be ignored when assessing representative in situ stress states?; what aspect of fracture perturbs the stress indicator? To address these questions, we carried out a series of 3D finite element modeling, in which the rock mass consists of a single competent rock type (metamorphosed tuff) with a thin and soft planar fracture crossing the model. A borehole penetrates the center of the model vertically. The fracture orientation was varied from model to model for a given far-field boundary stress condition. The model results show that the rotation of breakouts increases generally (but with wide scattering) with an increase in slip tendency of the fracture. A more detailed analysis shows that the azimuthal rotation of breakouts tends to increase in a clearer manner with an increase in the horizontal shear displacement (or shear strain) component along fracture having relatively high slip tendency. For the reasonable values of mechanical properties assumed in the model, the breakout rotation can be as high as ~34° from the boundary stress orientation imposed in the model. Such stress rotation occurs throughout the extent of the fracture and is reflected in breakout rotation. The model results are quite comparable to the breakout rotations observed in the borehole. Our study suggests that breakout rotation is not just a local feature around the borehole but reflects a site-scale stress rotation associated with the presence of fractures having specific orientations and slip direction.
A probabilistic approach for planning the ordinary maintenance of existing torrent control structures: from first-level inspections to maintenance strategy
Authors: Cislaghi Alessio , Morando Paola , Morlotti Emanuele , Bischetti Gian Battista
Published: February 2023

Check dams, submerged and ground sills, ground ramps, and bendway weirs are in-channel countermeasures built for mitigating flood and debris flow hazards. These torrent control structures have an own durability depending on structure type, material, design, construction, and maintenance, as well as on the physical pressures exerted on them. During the last half-century, while the natural degradation of the structures endangers their functionality, investments in ordinary maintenance have been significantly decreasing, worldwide. Thus, monitoring and planning an ordinary maintenance of existing structures should be a primary purpose for maintaining (or even improving) an adequate level of protection against natural hazards.The present study proposes a framework for planning and promoting decision-making on the structure maintenance activities. The methodology consists in a procedure of first-level inspection based on three indicators (i.e., damage index, residual functionality, and active process index), followed by the application of a homogeneous Markov chain model on the collected field observations. The study has been conducted on three rivers in North Italy (Oglio, Pioverna, and Staffora) characterised by different hydrological-sediment transport regime, and level of artificiality.The results of the first-level inspections, merged with a wide spectrum of other information (width, length, height, age of construction, materials, etc.), clearly show the actual status of the structures, whereas the Markov chain model provides different scenarios of physical structure degradation and decline of functionality, in function of time and levels of maintenance.This framework is an interesting decision support tool for planning a long-term ordinary maintenance on torrent control structures, through a probabilistic assessment of structure failure, and a cost-effectiveness analysis of different maintenance activities. Moreover, this study represents a practical example of watershed management, starting from planning the first-level inspections of the existing torrent control structures until the assessment of the present and future vulnerability of the areas developed along the river channel network.
A physics-informed machine learning approach to estimate surface soil moisture
Authors: Singh Abhilash , Gaurav Kumar
Published: February 2023

We propose Physics Informed Machine Learning (PIML) algorithms to estimate surface soil moisture from Sentinel-1/2 satellite images based on Artificial Neural Networks (ANN). We have used Improved Integral Equation Model (I2EM) to simulate the radar images backscatter in VV polarisation. In addition, we selected a set of different polarisations, i.e.; (VH, VH/VV, VH-VV), incidence angle, Normalised Difference Vegetation Index (NDVI), and topography as input features to map surface soil moisture. We have used two different approaches to predict soil moisture using PIML. In the first approach, we developed an observation bias in which we selected the difference of backscatter value at each pixel in VV polarisation from satellite and derived from theoretical model derived as one of the input features. Our second approach is based on learning bias, in which we modified the loss function with the help of the I2EM model. Our result shows the learning bias PIML outperforms the observation bias PIML with R = 0.94, RMSE = 0.019 m3/m3, and bias = -0.03. We have also compared the performance with the standalone benchmark algorithms. We observed the learning bias PIML emerged as the most accurate model to estimate the surface soil moisture. The proposed approach is a step forward in estimating accurate surface soil moisture at high spatial resolution from remote sensing images.
Estimating orbital elements from VLBI observations and GNSS measurements
Authors: Wolf Helene , Böhm Johannes , Hugentobler Urs
Published: February 2023

Over the last years, ideas of installing a dedicated Very Long Baseline Interferometry (VLBI) transmitter on board of the second generation of Galileo satellites have been proposed. The mounting of such a transmitter on future satellites raises scientific questions and opens new opportunities of extending the current VLBI research with observations to geodetic satellites. These observations allow combining the satellite and the quasar frame due to the unique opportunity of determining the satellite orbit in the International Celestial Reference Frame (ICRF).In this contribution, we present the estimation of orbit arcs based on VLBI observations combined with GNSS measurements. For this purpose, schedules including satellite and quasar observations, are created with the scheduling software VieSched++. These schedules are simulated and analyzed with the Vienna VLBI and Satellite Software (VieVS). In the analysis the partial derivatives of the state vector of the satellite with respect to the orbital elements, obtained from the module ORBGEN in Bernese, are used in VieVS for calculating the partial derivatives of the time delay with respect to the orbital elements. This approach allows to estimate the orbital elements from simulated VLBI observations. The quality of the estimated parameters is investigated and assessed based on the mean formal errors and the repeatabilities.In a further step there is the option to combine the results from VieVS and Bernese at the normal equation (NEQ) level using the ADDNEQ2 and retrieve fully consistent orbital parameters based on VLBI and GNSS observations.
Soil inorganic carbon: stocks, functions, losses and their consequences
Authors: Zamanian Kazem , Kuzyakov Yakov
Published: February 2023

Carbonate-containing minerals comprise an additional form of soil carbon known as soil inorganic carbon (SIC). Though SIC stocks are large, they have been disregarded in most studies to carbon sequestration. After reviewing the main forms of SIC (geogenic, biogenic and pedogenic carbonates) and the chemical processes leading to formation of pedogenic carbonates, we review the importance of SIC in the global C cycle and ecosystem functions. Besides pH regulation, SIC and dissolved Ca2+ from carbonates dissolution: i) increase plant growth due to better root growth, nutrient availability and acquisition, as well as provide protection against pathogens; ii) increase activities of soil microorganisms mineralizing nutrients; and iii) bind organic compounds which, consequently, stabilize organic matter, produce larger and stable aggregates, and control water permeability and balance. Consequently, the SIC is crucial not only for pH regulation, but also strongly contributes to many other soil functions and health. Finally, we assess future SIC losses under anticipated global change processes such as increased N deposition and fertilization, elevated CO2, invasive plant distribution and climate change. These SIC losses damage soil functionality and make it more vulnerable to a broad range of degradation factors, including erosion, topsoil and subsoil compaction, acidification and nutrient depletion. Crucial is that in contrast to organic carbon, the SIC losses are irrecoverable. We conclude that SIC is an important soil constituent responsible for a broad range of physical, chemical and biological soil properties and processes as well as ecosystem services such as cycles of C, N and other elements.
Effects of Trenches Filled with Compost or Tuff on some Properties of a Clayey Soil Irrigated with Secondary Treated Waste Water.
Authors: Levy Guy , Zireeni Yusra , Bar-Tal Asher
Published: February 2023

Irrigation with secondary treated waste water (TWW) may harm soils, especially clayey ones, through increasing soil salinity and sodicity that subsequently impair its physical and hydraulic properties. We compared the effects of TWW-irrigated  compost and tuff trenches placed in an almond orchard of Kibutz Lavee, Israel, on  properties of a clayey soil to those of TWW or fresh water (FW) irrigation.  Both types of trenches did not reduce soil sodicity (expressed in terms of sodium adsorption ratio, SAR). Compost trenches had no effect on soil salinity while the Tuff ones reduced salinity.  Compost trenches increased soil water content and oxygen concentration, whereas Tuff increased aeration but not soil water content. All treatments irrigated with TWW did not improve aggregate stability relative to irrigation with FW. We conclude that compost and tuff trenches could be considered as solutions for enhancing aeration in the root zone and thus potentially improve crop performance.
The Genesis of Nephrite— Geochemical Constraints by B isotopes, Sr isotopes and Trace Elements
Authors: Pi Ju-lien , Chen Huei-Fen , Chao Hung-Chun
Published: February 2023

Nephrite had long been mined as resources of gemstone in eastern Taiwan. It outcrops in the orogenic mountain, the Central Range, where the black schist dominates and the ultramafic serpentinites distribute sparsely. The orogeny has occurred when the subduction (South China Sea subducted to the Philippine Sea Plate) ceased and collision began at about 5 Ma. Observations shows the nephrite occurred at the interface of serpentinite and the Clinozoisite schist, enriched in Cr, Ni, but also Ca. The genesis of nephrite had been thought as a result of a series of complex reactions include the metasomatism of ultramafic rock and its surroundings and succeeding fluid interactions. This study conducts B isotopes, Sr isotopes and trace elemental measurement to give further geochemical constraints on the genesis of nephrite. Samples include rocks--black schist, clinozoisite schist, serpentinite, and associated minerals—nephrite, diopside, calcite, tremolite asbestos, cat’s eye nephrite and talc. The Sr element are enriched in clinozoisite schist, calcite, black schist (1005 ppm, 285 ppm~545 ppm, 150 ppm, respectively), and rather depleted in nephrite, diopside, cat’s eye nephrite, tremolite asbestos, serpentinite (4.3 ppm, 5.6 ppm, 3.2 ppm, 2.5 ppm, 2.0 ppm, respectively). Despite the huge difference in Sr contents, the 87Sr/86Sr ratios of all the samples are in the range of 0.71424 ~ 0.71815, with the highest in serpentinite (0.718151) and lowest in clinozoisite schist, nephrite and clacite (0.714240, 0.714788, 0.714951~ 0.715925, respectively), indicate the Sr source from continental crust majorly. The B concentrations and δ11B values are: in serpentinite ~21 ppm and -0.5 ‰, in nephrite ~5 ppm and -6.1 ‰, in clinozoisite schist ~2.5 ppm and -5.9 ‰. The B isotopes characterize the serpentinite as of “subduction zone type”. The isotopes study provides constraints to the genesis of nephrite and thus a possible viewpoint: although the immobile elements, e.g. Cr, Ni, shows the nephrites origin from serpentinite, its different 87Sr/86Sr ratios from serpentinite indicates later flushing by fluids which are similar to those in clinozoisite schist and calcite. And the nephrite’s lower B concentrations and δ11B values than in serpentinite may result from the flushing (replacement) of later fluids or dehydration processes, or both. Further discussions combining the viewpoints of mineralogy would be necessary to make more comprehensive interpretations.
Combining high-resolution in-situ water isotope measurements with 1D soil hydraulic and transport modelling to understand root water uptake dynamics in a mixed forest ecosystem
Authors: Mach Judith , Kinzinger Laura , Seeger Stefan , Haberstroh Simon , Dubbert Maren , Werner Christiane , Weiler Markus , Orlowski Natalie
Published: February 2023

Soil-plant interactions and root water uptake are important factors of the soil-plant-atmosphere continuum. Characterizing root water uptake dynamics in different forest stands can help to predict water stress due to climate change. Governing factors that define tree root water uptake are environmental conditions, soil hydraulic properties, species-specific rooting patterns as well as intra- and interspecific competition. As spatial-temporal patterns of root water uptake cannot be measured directly, simplified assumptions are often either based upon homogenous soil conditions or on a static root water uptake profile. This study combines high-resolution in-situ measurements of water stable isotopes of xylem and soil moisture with a set of 1D soil hydrological and transport models of the vadose zone (Hydrus 1D) to investigate dynamics in root water uptake patterns of two competing tree species in three different forest stands. We measured in-situ water isotopic signature in different soil depths as well as in spruce and beech xylem continuously for two vegetation periods (2021-2022) including two artificial tracer experiments, a wet period in 2021 and a drought period in 2022. Three stands were compared: i) pure beech, ii) pure spruce and iii) mixed beech and spruce, measuring sap flux, leaf water potential, soil moisture, matric potential, throughfall and stemflow. In order to address different factors of soil heterogeneity, the vadose zone is represented by a set of models covering the range of measured soil conditions. Each model is calibrated against soil water content as well as isotope measurements and subsequently related to sap flux measurements. This allows for separating effects of soil heterogeneity and to analyze the interplay of a) stand specific factors, particularly different rooting distributions, interception, and throughfall patterns, and b) soil specific factors, particularly different hydraulic conductivity and plant available water fractions under changing environmental conditions. Results show that this interplay between soil and stand specific factors is crucial under dry conditions, while soil specific factors are of minor importance under wet conditions. This contribution will present and discuss results from this data-driven modelling study and provide information about how well processes are represented in these kind of models.
Mucilage enables water uptake in cowpeas (Vigna unguiculata L.) under soil water deficit
Authors: Abdalla Mohanned , Ahmed Mutez
Published: February 2023

Various rhizosphere traits have been explored as plant adaptations to modulate the soil-root interface to acquire resources and to enhance plant water status under stress conditions. Mucilage exudation has been suggested to enable water uptake during soil drying. This hypothesis was tested using artificial root analogy due to technical limitations and the lack of suitable plant materials. Here, we tested whether mucilage exudation facilitates water uptake in intact cowpeas (Vigna unguiculata L.) plants growing in loamy soil during drying. We used a root pressure chamber system to measure the gradients in water potential at the root surface as well as the relationship between transpiration rate and leaf xylem water potential in two genotypes with contrasting mucilage production. Higher mucilage exudation attenuated the drop in matric potential at the root surface. In contrast, the gradients in water potential were much steeper in cowpea with less mucilage production. The attenuation of matric potential at the root surface resulted in a linear relationship between transpiration rate and leaf xylem water potential. We conclude that mucilage exudation maintains the hydraulic continuity between roots and soil and decelerates water potential dissipation near the root surface during soil drying. Our findings provide the first in vivo evidence on the role of mucilage on root water uptake.
Can sand nourishments counteract the consequences of climate change while preserving ecosystems: A case study
Authors: Glueck Daniela
Published: February 2023

In order to adapt to sea level rise, sand nourishments are one of the measures to protect the coast from erosion and stabilize shorelines. Marine sands are being dredged from the ocean floor and nourished onto the beach or in the shallow water. To understand the ecological effects of these measurements, the following case study was performed. Both short and long-term effects on aquatic and terrestrial coastal ecosystems were monitored during a 24 months survey which started in June 2021 in Ahrenshoop at the Baltic Sea (Germany). Sediment structure and vegetation along the nourished beach as well as the turbidity plume caused by the nourishment were monitored.It was shown that it takes around 6 months until the sediment and water conditions prior to the nourishment are met again. This is due to the mechanism of the nourishment itself and depending on the nourished sediment. The algae vegetation was only influenced by seasons and not affected by the nourishment. In contrast, there were major changes in vegetation of the dune since part of the dune was burrowed under the nourished sand. The vegetation coverage decreased as well as the biodiversity in the primary and secondary dune which both were buried under a new layer of sediment that was significantly different and only Ammophila arenaria was restored there. The tertiary dune was not directly affected by the nourishment. Nevertheless, comparisons of the dune with unnourished dunes showed overall lower biodiversity including the tertiary dune.Sand nourishments can change the ecology of a coastal ecosystem. Even after reinstating similar sediment parameters, the results of the case study suggest that long-term effects occur regarding vegetation of the dune. 
Estimation of N and N₂O cycling processes using the information of bacterial functional genes in the East Sea
Authors: Kim Hyo-Ryeon , Lim Jae-Hyun , Jung Hae-Kun , Kim Seo-Young , Kim Il-Nam
Published: February 2023

Marine nitrogen (N) cycle plays important roles in controlling marine ecosystem and biogeochemistry, as it is well known as a limiting element for marine productivity and significantly influences on the carbon and phosphorus cycles in the marine environment. Also, nitrous oxide (N₂O) production via marine N cycling is regarding as climate interaction with a big concern owing to its significant warming potential in the atmosphere. The East Sea (ES) is a semi-enclosed marginal sea, but frequently referred to as a miniature ocean as it shows multiple ocean dynamic processes. Recently, a number of studies reported that the ES is rapidly changing due to anthropogenic perturbations. Given that understanding of the ES’s biogeochemical cycles under such a condition is apparently urgent, we have little knowledge about particularly N cycling and N₂O production mechanisms to date. At present, the application of metagenomics approaches is widely used for understanding marine N cycle as an important means. Here, using the information of bacterial functional genes, we for the first time investigate (1) N cycling processes and (2) N2O production pathways during June and October 2021 at three different depths (0m, 150m, and 750m) of the ES.
Subseasonal strength reversal of the East Asian winter monsoon
Authors: Zhong Wogu , Wu Zhiwei
Published: February 2023

As one of the most significant circulation systems over the Northern Hemisphere in the cold season, the East Asian winter monsoon (EAWM) has been broadly investigated from the seasonal-mean perspective, while subseasonal variations in the EAWM still remain ambiguous. Based on Season-reliant Empirical Orthogonal Function (S-EOF) analysis, this study shows that the subseasonal strength reversal of the EAWM (SR-EAWM), featuring a weaker (or stronger) EAWM in early winter (December) and a stronger (or weaker) EAWM in late winter (January-February), is a distinct leading mode of the month-to-month variation of the EAWM. The weak-to-strong SR-EAWM is characterized by an anomalous low over Eurasia and a weakened East Asian major trough (EAT) in early winter, with an intensified Siberian High and a deepened EAT in late winter. The SR-EAWM is preceded by surface air temperature anomalies over Davis Strait (DST) and those over central-eastern North America (CENAT) in September-October. The DST mainly influences the SR-EAWM in early winter through a “sea ice bridge” of the November Baffin Bay sea ice concentration anomaly (BBSIC). The BBSIC could intensify the DST in December by altering surface heat flux, thus exciting a downstream atmospheric response and modulating the strength of the EAT in early winter. The preceding CENAT affects the SR-EAWM in late winter by inducing an “ocean bridge” of the western North Atlantic sea surface temperature anomaly (WNASST). The WNASST can persist into late winter and then significantly affects the SR-EAWM by regulating Eurasian circulation anomalies and the downstream EAT. The bridge roles of the BBSIC and WNASST can be further verified by a linear baroclinic model. Finally, two physical-empirical models are established using the DST/BBSIC and the CENAT indices, respectively. Both exhibit promising prediction skills. The results highlight that the DST, BBSIC, and CENAT are crucial predictability sources for the SR-EAWM.
Development of time-gated Raman proximal sensing for an earth observation platform
Authors: Havisto Jari , Köhler Martin , Uusitalo Sanna , Paavola Marko , Knobloch Andreas , Rahkamaa-Tolonen Katariina
Published: February 2023

The Goldeneye project combines remote sensing and positioning technologies with proximal sensing to produce reference calibrated mineralogical maps through data fusion. The project brings together optical satellite sensor data, drone sensor aerial data both optical and electromagnetic as well as spectral ground sensor data. Satellite data can offer spectral signatures of large areas but suffers from limited spatial resolution and blind spots where the higher resolution satellite data is not available. Drone data can offer more variety in spectral wavelengths with higher resolution but there are some drawbacks as well. Namely, NIR vibrational spectroscopy requires background information for successful mineralogical analysis. In addition, the most interesting SWIR range is challenging due to large and very expensive sensors. To cope with these challenges of aerial data, proximal sensing can be applied in locations where satellite imagery is not available, and it can also produce reference information for the calibration of the spaceborne and airborne instruments. The conventionally used analyses for producing mineralogical information from field collected samples are the mineral liberation analysis (MLA) and X-Ray diffraction (XRD) which require extensive sample preparations and are laborious and slow. Goldeneye-project has studied the use of time-gated Raman for easier and more practical production of reference data at the field sites as well as from field collected rock samples. The benefit of Raman is an accurate characteristic spectral fingerprint and an ability to distinguish small mineralogical features as the detection spot is in the range of hundreds of microns. There are continuous wave Raman spectrometers, which are already field deployable. However, conventional Raman suffers from the auto-fluorescence emission triggered by the laser illumination, especially in light-colored rock samples. Time-gated (TG) Raman has the benefit of time-resolved sensing, where the Raman scattering is recorded before the fluorescence signal is over-powering the weaker scattered signal. TG-Raman can thus offer information from a wider variety of geological specimen than the conventional Raman. In Goldeneye-project, TG-Raman spectra were collected with custom sampling solution from mineral samples and drill cores from Erzgebirge exploration site in Germany. The data was analysed together with pXRF reference data to assess the benefit of the data fusion.The paper has been prepared in the frame of the Horizon 2020 co-funded project GOLDENEYE, which has received funds through the Grant Agreement 869398.
Groundwater Quality Assessment and Geochemical Mechanism of Groundwater of Komadugu-Yobe Basin, West Africa
Authors: Shuaibu Abdulrahman , M. Kalin Robert , Phoenix Vernon
Published: February 2023

The assessment of groundwater quality and its geochemical mechanism is crucial for the sustainable use and management of groundwater resources in arid and semi-arid regions of developing nations. 120 groundwater samples were collected from the Komadugu-Yobe basin to determine its overall quality and the factors that controls the geochemical mechanisms of the groundwater of the study region. The pH, electrical conductivity (EC), and total dissolved solids (TDS) of the groundwater samples were analysed in situ using a handheld (Model 99720 pH/Conductivity meter). The concentrations of Na+, Ca2+, Mg2+, and K+ were analyzed using ICP-OES, iCAP 6200, Thermo Fisher Scientific while Cl-, F-, SO42-, and NO3- were analysed using Ion Chromatography (Metrohm 850 Professional IC). Moreover, the total Alkalinity and bicarbonate were determined using KONE Aquakem v. 7.2.AQ2 equipment by titrimetric method. The hydrochemical analysis results reveals that less than 10% of the groundwater samples exceeded the maximum permissible limits for Electrical conductivity, total dissolved solids, total hardness, sodium, potassium, calcium, magnesium, chloride, sulfate, and fluoride for drinking purposes as recommended by the world Health Organization (WHO, 2018) standards except for bicarbonate and nitrate. The Gibbs diagrams reveals that rock-weathering/rock water interaction is the dominant mechanism controlling groundwater of the study region. However, the chemical relationships in Piper trilinear plots identified Ca2+-Mg2+- HCO-3 water type predominated the study area constituting about 59% of the groundwater samples collected. The findings of the study are paramount for implementing a sustainable management strategy of groundwater resources in the Komadugu-Yobe basin towards the realization of Goal 6 of sustainable development goals.Keywords: Groundwater, Komadugu-Yobe basin, Geospatial analysis, Water quality, Rock-water interaction
The value of mixed distribution approaches for low-flow frequency analysis
Authors: Laaha Gregor
Published: February 2023

Extreme value statistics are well established for floods and are also receiving increasing attention in drought hydrology. They allow the user to characterize the severity of an event by a statistical probability or return period, a concept that is well understood in the scientific, policy, and public arenas. Frequency analysis is usually carried out on the basis of annual extreme event series, which  is straightforward in its application and interpretation. However, in seasonal climates with a warm and a cold season, the low-flows can be generated by different processes, which violates the basic assumptions of extreme value statistics and can lead  to inaccurate conclusions.Here we assess the value of a mixed distribution approach for low-flows to perform frequency analysis in catchments with a mixed summer/winter regime. We first present the theoretical concept of the mixed probability estimator for low-flows. We then illustrate the characteristics of the model for archetypal low-flow regimes, from pronounced summer and winter regimes to flow mixtures with weak seasonality. We successively evaluate the gain in performance from the mixed distribution model for a range of low flow regimes, based on a comprehensive Austrian dataset. We finally scrutinize the assumption of the mixed probability estimator and review the added value of using an extended, Copula-based  framework. The results show large differences of event return periods, and suggest that the mixed estimator is relevant not only for mountain forelands, but for a much wider range of catchment typologies across Europe. These even include typical summer regimes when only single winter low-flows are mixed in. We conclude that the mixed distribution approaches outperform the conventional frequency estimator and should be used by default in seasonal climates where summer and winter low flows occur.
A data-model comparison of shallow marine seasonality during the Mid-Pliocene
Authors: de Winter Niels , Tindall Julia , Johnson Andy , Goudsmit Barbara , Wichern Nina , Huygen Fynn , Goolaerts Stijn , Wesselingh Frank , Claeys Philippe , Ziegler Martin
Published: February 2023

Accurate projections of future climate scenarios require a detailed understanding of the behavior of Earth’s climate system under varying radiative forcing scenarios. The mid-Piacenzian Warm Period (mPWP; 3.3 – 3.0 Ma) was characterized by atmospheric CO2 concentrations comparable to present-day values (~400 ppmV), while global mean annual temperatures were roughly 2-3 degrees warmer compared to pre-industrial climate (Haywood et al., 2020). Seasonally resolved climate records from fossil bivalve shells offer a snapshot of short-term variability in temperature and salinity under the mild greenhouse conditions of the mPWP (Wichern et al., 2022).In this study, we combine a large dataset of clumped isotope measurements incrementally sampled in fossil shells from the North Sea area during the mPWP with climate model simulations for the same time period using the PlioMIP model comparison framework. This combination of data and models allows us to test whether the climate models in PlioMIP can pick up the sub-annual scale variability in temperature and salinity (reconstructed via the oxygen isotope composition of the paleo-seawater). We show that, in contrast to continental reconstructions used in previous PlioMIP data-model comparisons (Tindall et al., 2022), our shallow marine data is reproduced well by PlioMIP models. On average, both model and data show considerably (4-5°C) warmer summer sea surface temperatures during the mPWP while winter temperatures remain relatively close to pre-industrial values. This suggests that the North Sea region can expect warming concentrated in the summer season in response to elevated atmospheric CO2 conditions.ReferencesHaywood, A. M., Tindall, J. C., Dowsett, H. J., Dolan, A. M., Foley, K. M., Hunter, S. J., Hill, D. J., Chan, W.-L., Abe-Ouchi, A., Stepanek, C., Lohmann, G., Chandan, D., Peltier, W. R., Tan, N., Contoux, C., Ramstein, G., Li, X., Zhang, Z., Guo, C., Nisancioglu, K. H., Zhang, Q., Li, Q., Kamae, Y., Chandler, M. A., Sohl, L. E., Otto-Bliesner, B. L., Feng, R., Brady, E. C., Von der Heydt, A. S., Baatsen, M. L. J., and Lunt, D. J.: A return to large-scale features of Pliocene climate: the Pliocene Model Intercomparison Project Phase 2, Climate of the Past, 2020.Tindall, J. C., Haywood, A. M., Salzmann, U., Dolan, A. M., and Fletcher, T.: The warm winter paradox in the Pliocene northern high latitudes, Climate of the Past, 18, 1385–1405, https://doi.org/10.5194/cp-18-1385-2022, 2022.Wichern, N. M. A., de Winter, N. J., Johnson, A. L. A., Goolaerts, S., Wesselingh, F., Hamers, M. F., Kaskes, P., Claeys, P., and Ziegler, M.: The fossil bivalve Angulus benedeni benedeni: a potential seasonally resolved stable isotope-based climate archive to investigate Pliocene temperatures in the southern North Sea basin, EGUsphere, 1–53, https://doi.org/10.5194/egusphere-2022-951, 2022.
Estimating the Anisotropic Factor of Angular Distribution Models from Radiative Fluxes
Authors: Liu Huizeng , Zhu Ping , Huang Shaopeng , Li Qingquan
Published: February 2023

Global climate change has aroused widespread concerns in society regarding the sustainable development of human beings. The Earth’s radiation budget (ERB) at the Top-of-Atmosphere (TOA) includes incident solar radiation, Earth-reflected shortwave radiation, and outgoing longwave radiation. The accuracy of the existing spaceborne instruments still cannot meet the measurement requirement of the Earth’s TOA shortwave and longwave radiation. In recent years, several novel observing platforms and sensors have been proposed for ERB. Hitherto, most of those concepts for ERB are still in the phase of design and development, and studies have been mainly carried out based on simulations. Simulating the sensor-measured signals of the proposed novel platforms, sensors or constellations could help to optimize the sensor parameters, determine the number of satellites in the constellation, explore their potentials in characterizing the ERB. The anisotropic factor, depicting the anisotropy of Earth’s radiation, is essential in the simulation. However, developing angular distribution models involves complex procedures of data preparation, processing, and modeling. This study, targeting at simplifying the procedure of simulating the signals of ERB sensors, proposed an approach of estimating the longwave anisotropic factors directly from the Earth’s radiative fluxes. The approach was implemented with CERES data and the neural network algorithm. Models were developed for 10 scene types based on Earth’s surface types. Results showed that the longwave anisotropic factors were accurately estimated with the correlation coefficient (r) varying between 0.85 and 0.98 and MAPE within 1.20% for the test dataset. With the estimated anisotropic factors, the sensor-measured radiances were accurately retrieved with r=1.00 and MAPE=0.53%. Therefore, the proposed approach is promising in accurate and efficient simulations of novel ERB platforms and sensors like the Moon-based Earth Radiation.
Impact of colder vs. warmer tropical sea-surface temperature on water isotopes in precipitation during the Last Glacial Maximum
Authors: Paul André , Tharammal Thejna , Werner Martin , Mulitza Stefan , Cauquoin Alexandre
Published: February 2023

Using the isotope-enabled atmospheric general circulation models iCAM5 and ECHAM6-wiso, we investigate the impact of relatively colder vs. warmer tropical sea-surface temperature on isotopes in precipitation during the Last Glacial Maximum. We forced the two models by the same sets of pre-industrial (PI) and Last Glacial Maximum (LGM) surface boundary conditions; the latter were taken from GLOMAP (Paul et al., 2021), which in turn were based on the MARGO project (MARGO Project Members, 2009) and recent estimates of Last Glacial Maximum sea-ice extent.To test the sensitivity to changes in tropical sea-surface temperature, we deliberately increased respectively decreased the reconstructed tropical sea-surface temperature by about 1.5 °C. We compared our model results to reconstructions from ice cores (cf. Risi et al., 2010) and speleothems (cf. Comas-Bru et al., 2020).  However, the resulting changes in water isotopes in precipitation were surprisingly small and difficult to detect, hence the sensitivity to changes in tropical sea-surface temperature is rather low. We discuss our results as well as the prospect of utilizing more sensitive proxy data that would allow to discriminate between the two sceanrios.
Quantification of gravity wave drag in ERA5 reanalysis
Authors: Procházková Zuzana , Pišoft Petr , Šácha Petr
Published: February 2023

Internal gravity waves (GWs) are a ubiquitous component of atmospheric dynamics, propagating both horizontally and vertically through the atmosphere, interacting with other flow components and affecting regional to large-scale dynamics. Due to the wide spectrum of GWs, model dynamics in general circulation models (GCMs) can resolve only part of the spectrum, leaving the effects of the unresolved part to be inserted by parametrisations. The analysis of high-resolution atmospheric datasets with resolved GWs allows us to understand GW dynamics and their effects on the mean flow, even in the long-term time-scales. In addition to this, such analysis enables validation of the parametrised effects and potential improvements of the parametrisations. In the presented work, we analyse resolved GWs in the ECMWF‘s ERA5 reanalysis, evaluating their effects on the flow through the GW drag.
Droughts in a human-dominated world: Feedbacks, legacies and inequalities
Authors: Di Baldassarre Giuliano
Published: February 2023

Societies have increasingly influenced the frequency and severity of hydrological drought over the past centuries by: i) building dams and reservoirs to secure water supply; ii) diverting water flows to supply cities, industries and agriculture; and iii) changing river basin characteristics through deforestation, urbanization and drainage of wetlands. While societies influence hydrological droughts, drought occurrences (and risks) influence societies. Adaptive responses include migration from drought-affected areas or changes in water allocation and governance. In this talk, I present case studies, global analyses and models to show how these sociohydrological feedbacks can generate legacy risks or social inequalities and thus challenge the development of sustainable policies of disaster risk reduction and water management. 
A decision support tool for evaluating the Ecological mitigation measures based on optimization algorithms
Authors: Kim Eun-sub , Lee Young-suk , Lee Dong-kun , Jung Hui-cheul , Hyun Jung-hee , Kim Seong-cheol
Published: February 2023

A recent issue highlights the need for Ecological mitigation measures to mitigate habitat and biodiversity loss caused by increasing human disturbance and urban development. Ecological mitigation measures have become quite effective and efficient in habitat preservation and reducing the extinction rate of the population. In this study, a decision support tool was developed to mitigate environmental impacts on urban development using optimization algorithms. This study seeks to identify a spatial planning model that determines the optimal location and type of mitigation measures based on increasing biodiversity and mitigating the impact of species on urban development and calculates the implementation cost using meta-heuristic optimization algorithms.We used the evaluation fitness value as landscape structural and functional and threat factors. It is possible to analyze the biodiversity and connectivity using the landscape pattern index and landscape connectivity. As a result of this study, the optimal location of ecological mitigation measures (ecological corridor, guide fences, and alternative habitats) was different for each species, and the Pareto plan showed that a trade-off effect was presented between cost and environmental impact minimization. Then we validated through comparison between the results of the optimization model and planning mitigation in the previous report. It is also expected to increase the effectiveness of the mitigation measures with a flexible model that can be planned within a limited cost.This work was supported by Korea Environment Industry &Technology Institute(KEITI) through "Climate Change R&D Project for New Climate Regime." , funded by Korea Ministry of Environment(MOE) (RE202201509) 
Greenhouse gas emission from vehicles in Seoul megacity, South Korea: Molar ratios (N2O:CO2, CH4:CO2) and stable isotopic compositions of N2O (d15N, d18O)
Authors: Kim JeongEun , Ahn Jinho , Ghosh Sambit
Published: February 2023

Fossil fuel combustion is one of the largest contributors to anthropogenic greenhouse gas (GHG) emissions, especially in megacities around the world. To characterize the vehicle emissions in Seoul, the megacity of South Korea, we collected air samples from the entry and exit points of three tunnels (Sang-Do, Bong-Cheon, and Gwan-Ak Tunnel) and Seoul National University Campus and measured dry molar mixing ratios of major greenhouse gases spices (CO2, CH4, and N2O). The N2O:CO2 emission molar ratio from vehicles is 4.3 ± 0.3 × 10-5, within a range of 1.8 – 18.7 × 10-5 previously reported in Germany, Switzerland, Sweden, and the USA. The CH4:CO2 emission molar ratio from the Sang-Do tunnel is 50.6 ± 18.0 × 10-5, which is significantly greater than those observed in Switzerland, the USA, and China (3.5 - 15 ± 4 ×10–5). In the Bong-Cheon and Gwan-Ak tunnels, however, there was little difference in entry and exit, or rather, the exit was smaller, and it might be related to the ventilation system and vehicle types. We also compared our estimation of the GHG emissions from vehicles with the National Greenhouse Gas Inventory Report of Korea (GIR, 2021) which is based on a bottom-up emission calculation method. With the CO2 emissions (8108.33 Gg CO2eq) from the GIR, the N2O and CH4 emissions in Seoul are estimated to be (108.08±24.60) Gg CO2eq and (62.75±18.92) Gg CO2 eq, respectively. The differences between our observations and inventory imply that the estimation of the non-CO2 gas (CH4, N2O) emission factors should be improved. To characterize the N2O from vehicles, we analyzed N2O stable isotopic compositions by an IRMS method. The δ15N and δ18O values of N2O emitted from the vehicles are estimated as -7.1 ± 1.5 ‰ and 41.2 ± 0.2 ‰, respectively. The δ15N values support the idea that the N2O is produced through catalytic convertors in vehicles which are attached to reduce the NOx emission at the tailpipe. The newly measured data from Seoul may help us better understand greenhouse gas emissions from vehicles in megacities.
Risk assessment of waterborne virus in Lake Geneva: the present and the future
Authors: Li Chaojie , Sylvestre Émile , Julian Tim , Kohn Tamar
Published: February 2023

The presence of waterborne enteric viruses in lake recreational water sites is not desired, as they may have a negative impact on human health. However, their concentrations, fate and transport in lakes remain poor understood. To date, the health risks posed by enteric viruses in surface water was typically assessed via monitoring of fecal indicators, such as E. coli, whereas a direct assessment of fate and transport of waterborne viruses is less common. In this study, we propose a coupled water quality and quantitative microbial risk assessment (QMRA) model to study the transport, fate and infection risk of four common enteric viruses, using Lake Geneva as a study site. The measured virus load in raw sewage entering the lake was characterized, fitted with different distributions and then used as the source term in the water quality simulations. A Eulerian transport model was employed to model virus transport while considering spatially and temporally varying inactivation of viruses. Eventually, the probability of infection was quantified by linking the virus concentrations at a popular beach with QMRA. The model framework was then applied to model current situations as well as future scenarios under climate change. In the simulations of year 2019, it was found that environmental stressors noticeably reduce the infection probability exerted by viruses with low background inactivation in summer, but effects in the winter are minor. Norovirus appeared to be the most abundant species and also led to the highest infection probability, which was at least 10 times greater than that of the other viruses studied. In addition, the model highlighted the role of the wind field in conveying the contamination plume and hence in determining infection probability. The simulations for the future revealed an increase of virus inactivation rates in summer times due to higher water temperature as well as increased radiation levels due to reduced cloud coverage. The enhanced inactivation in summer could compensate for the higher virus loading caused by population growth. In contrast, in winter minor temperature changes and inconsequential radiation variation would not offset the increased virus loading. However, even in the winter cases the future infection risks would not undergo significant change compared with the current situation.  The proposed model framework is flexible and could be relatively easily refined and adapted for other locations and scenarios. This study highlights the potential of combining water quality simulation and virus-specific risk assessment for a safe water resources usage and management.