bluuebunny/crossref_metadata_2025 huggingface dataset:
Combining low level labelling with 15N and 15N site preference to distinguish N2O production by nitrification and fungal denitrification
Authors: Rohe Lena , Well Reinhard
Published: February 2023

Isotopocules of the greenhouse gas nitrous oxide (N2O), i.e. δ18O, average δ15N (δ15Nbulk), and 15N site preference (SP) values were used to distinguish between N2O production pathways in soil. However, as many N2O production pathways coexist and N2O can be reduced to N2, it is not possible to distinguish pathways based only on the natural abundance of N2O. This applies especially to nitrification and fungal denitrification, where the specific high SP values overlap. Combining 15N tracer approaches and natural abundance approaches (especially using SP values) could serve to disentangle such pathways, but with the disadvantage that both approaches have to be carried out as parallel experiments.With this contribution, we present an experimental concept based on the theory, that low level labelling with 15N of N2O precursors may allow both, a clear distinction of nitrate or ammonium (NO3- or NH4+, respectively) derived N2O fluxes by 15N tracing, and the use of SP values of N2O as additional constraint. This could potentially expand possibilities to evaluate and validate current natural abundance isotopocule mapping approaches.We will present first results of three experiments to investigate the impact of low labelled precursors on SP values of N2O produced. Each experiment included treatments with unlabeled and low labelled 15N precursors to test if low labelling with 15N affects N2O isotopocules. In one incubation experiment (i) various levels of 15N labelling of NO3- (between 0.6 and 5 at% 15N) were used for incubations with Pseudomonas aureofaciens. In another experiment (ii) two pure bacterial (P. aureofaciens and Paracoccus denitrificans) and one pure fungal culture (Fusarium oxysporum) known to be capable of reducing NO3- or NO2-, respectively, were used. In all experiments, isotopocules of N2O were unaffected by N2O reduction as this reduction step could be excluded with selected species. To further investigate isotopocules of N2O affected by co-occuring processes as well as N2O reduction a third incubation experiment with two repacked soils was conducted. For this approach, nitrification and/or denitrification was induced by applying NH4SO4 and KNO3 as N2O precursors, either unlabeled in one treatment or with 15N labelled KNO3 (max. 1.1 at% 15N) in another treatment, both under dry (40% water filled pore space (WFPS)) or wet (80% WFPS) soil conditions.Based on the results presented, we will be able to give an outlook whether this method can be used to distinguish between nitrification and fungal denitrification.
Characterizing Emissions from Energy Sources Using Aerosol Properties Over Multiple-Wavelengths
Authors: Liu Zhewen , Cohen Jason Blake
Published: February 2023

Over the past decades there has been both rapid economic growth and increase in energy use in Asia. This has led to a rapid change in the emissions of aerosols and trace gases associated with climate and air pollution, having dramatic effects on the atmosphere. Aerosol absorption optical depth (AAOD) is a measure of the optical-physical-chemical information of particles which absorb visible and UV radation, including: black carbon (BC), dust, and brown carbon (BrC). This subset of total aerosols has a significant and unique effect on air pollution and climate change, including altering the radiative balance and impacting the hydrological cycle. Different unbiased models and methods based on non-aerosol measurments are used to disaggregate urban and industrial areas from suburban and rural areas. These regions are then sampled as constrained in space and time by MISR to elucidate and quantify information about the absorbing particle size distribution, ageing, and emissions in these rapidly changing and/or heavily polluted areas.To better understand AAOD and its impact on the atmosphere, this work uses both empirical orthogonal decomposition (EOF) and a MIE model based on a core/shell assumption, combining information from from both MISR AAOD and OMI NO2, to determine information about the geospatial and temporal distribution of absorbing aerosols, the size of these particles, regional differences, and physical and chemical properties. The AAOD is constrained by inverted NO2 emissions profiles to find the regional distribution of particulate matter. The differences in the observed values of SSA and AAOD over the four different visible bands are then used to drive the MIE model, which in turn is used to produce a probability distribution of the core size, shell size, and arosol mixing state. The inverse performance of the particle size distributions and mixing state are observed to be dramatically different over urban, industrial, and suburban areas, in specific during the times as constrained by OMI. The impacts of these changes to the atmospheric and radiative profiles over both the source regions are analyzed and used to further evaluate the atmospheric loading, transport, aging, and emissions of abosbing aerosols, with the goal of developing and quantifying the impacts on these regions undergoing the largest amount of change in the region.
Scenario simulations of marine ecosystem health on China’s coast
Authors: Hu Ziyuan , Sun Xiaoxia , Sun Song
Published: February 2023

Global climate change and extensive human activity put compounding pressure on coastal marine ecosystems, resulting in habitat degradation, a reduction in ecosystem services, and an increase in marine ecosystem disasters. Therefore, simulating the response of ecosystem health conditions to climate change and different human activity scenarios can provide direct and effective information to improve ecologically sound management strategies for the sustainable use and development of coastal areas. In the present work, we set up a scenario simulation model using machine learning methods. Individual and integrated scenarios of Climate change and human activity impact were designed to predict the possible responses of marine ecosystem health conditions. 
Wind-solar-storage trade-offs in a decarbonising electricity system
Authors: Gangopadhyay Anasuya , K. Seshadri Ashwin , Patil Balachandra
Published: February 2023

In a steadily decarbonizing electricity system, it becomes increasingly important to explore cost-effective wind-solar-storage combinations to replace conventional fossil-fuelled power generation without compromising grid reliability. For a renewable-rich state in Southern India (Karnataka), we systematically assess the economics of various wind-solar-battery energy mixes given decreasing fossil-fuelled base generation and hydropower availability using Pareto frontiers. Our approach considers hourly load data, simulates generation based on hourly weather reanalysis products, and models the effects of battery charging and discharging on battery lifetime. We find that the allowed curtailment level limits the achievable grid reliability. Given declining baseload generation and available hydropower in the state electricity grid, the wind-solar-battery combined system can provide limited reliability, which declines as the grid is progressively decarbonized. A fully decarbonized grid with 2 GW of hydropower and a stringent 10% curtailment threshold can achieve maximum reliability of 66%. These values are sensitive to available hydropower capacity, baseload generation from fossil fuel, and the curtailment threshold. For a fully decarbonized grid, increasing the allowed curtailment threshold of renewable generation (during times of excess) to 80% would ensure 99% grid reliability. However, such a solution would be costly, requiring large wind-solar installations that exceed officially assessed potential, constrained by land allocation. Furthermore, these calculations show that adding storage capacity without concomitant expansion of renewable generation capacity is inefficient. The findings highlight the importance of a fresh examination of curtailment thresholds, renewable potential, and possibilities of demand-side management to evaluate pathways to the decarbonization of the electricity grid while maintaining reliability.
Identification of cirrus formation regimes using cluster analysis of back trajectories and satellite data
Authors: Jeggle Kai , Neubauer David , Lohmann Ulrike
Published: February 2023

In recent years our understanding of cirrus cloud processes has been significantly advanced. However, a large uncertainty regarding the influence of cirrus formation mechanisms on the microphysical properties, and hence radiative properties of cirrus clouds still remains. This leads to uncertainty in global climate models and climate change projections. In this work we aim to identify different cirrus formation regimes and analyze their influence on cirrus microphysical properties. We combine DARDAR-Nice satellite observations with Lagrangian back trajectories of meteorological and aerosol reanalysis data on the Northern Hemisphere. Our goal is to classify observed cirrus clouds by means of their trajectories and investigate the trajectories' influence on observed cirrus microphysical properties. With our data-driven nested clustering approach we identify different meteorological regimes that lead to cirrus formation. We are also able to isolate the effect of dust ice nucleating particle (INP) exposure along the trajectory from meteorological variability.
We identify four different meteorological clusters that lead to characteristic cirrus cloud microphysical properties and can be associated with liquid origin and in-situ formed cirrus clouds. Furthermore, we find that dust concentrations in cirrus cloud back trajectories are significantly higher compared to cloud free trajectories with comparable meteorological conditions. This indicates the importance of dust acting as INP during heterogeneous nucleation. The magnitude of the dust concentration, however, has only a negligible effect on cirrus microphysical properties.
Better considering tracer distribution within boreholes while FVPDM tests
Authors: Brouyère Serge , Simon Nataline , Jamin Pierre
Published: February 2023

Characterizing groundwater fluxes is essential in many hydrogeological studies, especially to assess contaminant transport in the subsurface. In this context, the Finite Volume Point Dilution Method (FVPDM) is a single-well experiment consisting in continuously injecting a tracer into a well and monitoring the evolution of the tracer concentration into the same well. A part of the injected tracer is carried out of the well by the groundwater flow and therefore the higher the tracer dilution, the lower the tracer concentration remaining in the well. In such tests, the water within the tested interval has to be continuously mixed using a mixing pump in order to perfectly homogenize the tracer concentration. Yet in practice, when FVPDM are performed in long-screened boreholes or in very permeable aquifers, it can be technically difficult to maintain a mixing important enough so that the tracer concentration is homogenous along the well. In order to assess the effect of non-perfect mixing on FVPDM results, we introduce here a new discrete model that explicitly considers the recirculation flow rate. The mathematical developments are validated using field measurements resulting of FVPDM tests performed under pumping conditions in a high hydraulic conductivity aquifer. Additionally, a sensitivity analysis was performed in order to assess the effect of recirculation flow rate and to define the limits of the FVPDM and the advantages of the discrete model. Results confirm that it is essential to accurately consider the recirculation flow rate when performing FVPDM in the field. Non-perfect mixing occur as soon as the recirculation flow rate applied is not high enough compared to the groundwater flow rate. In this case, the tracer concentration is not uniform with decreasing tracer concentrations along the tested interval. Since the tracer concentration is measured within the recirculation loop (which helps the mixing of the tracer), neglecting the recirculation flow rate during field data interpretation can lead to significantly overestimate groundwater fluxes if the classical analytical solution is applied to interpret tracer concentration evolution. The discrete model introduced here, which was validated through field measurements, can be used instead to properly estimate groundwater fluxes and assess the tracer distribution within the tested interval.
Extreme high daily maximum temperature in the USA by the 2050 and 2100 horizons
Authors: Parey Sylvie , Collet Lila , Griffin Kristen
Published: February 2023

Electricity generation assets need to withstand climatological hazards all along their operating period. With the ongoing climate change, high temperature extremes are expected to increase, therefore, climate change needs to be accounted for in the estimations of extreme temperature levels at the design stage.This study showcases a methodology designed to compute maps of daily maximum temperature return levels in summer over the continental USA by 2050 and the end of the century. The methodology first consists in building a variable whose extremes can be considered as stationary in order to then apply the statistical Extreme Value Theory to compute return levels. Previous studies (Parey et al., 2013) had shown that once the trends in mean and standard deviation are removed, the extremes of the reduced variable can be considered as stationary. The reduced variable is thus computed for daily maximum temperatures at each grid point across the continental USA in summer using the ERA5 reanalysis over the 1950-2014 period. Then, once the desired return level is estimated for this variable, temperature levels are obtained by re-introducing the removed information about the mean and the standard deviation of summer temperature at the desired horizon (Parey et al., 2013). To do so, a set of 9 CMIP6 climate models with 3 emission scenarios, SSP1-2.6, SSP2-4.5 and SSP3-7.0, is considered. For each time horizon, 27 extreme summer temperature maps are produced. Then, a criterium is designed to sum up the information and decide whether two different maps give significantly different results. Finally, once the criterium is applied to each pair of maps, either scenario by scenario or all scenarios together, a classification is applied to identify groups of statistically different maps.  References:Parey S., Hoang TTH, Dacunha-Castelle D.: The importance of mean and variance in predicting changes in temperature extremes, Journal of Geophysical Research: Atmospheres, Vol 118, 1-12, 2013, doi:10.1002/jgrd.50629Parey S., Hoang T.T.H., Dacunha-Castelle D.: Future high temperature extremes and stationarity, Natural Hazards, 2019, https://doi.org/10.1007/s11069-018-3499-
A method to estimate clear sky mesoscale vertical motion from geostationary satellite imagery
Authors: Poujol Basile , Bony Sandrine
Published: February 2023

Mesoscale vertical velocity is a key element to understand links between clouds, radiation and circulation. However, in situ measurements of this variable remain sparse and costly.Here, we present a method to estimate clear-sky free tropospheric mesoscale vertical motion from rapid-scan geostationary satellite radiance measurements in the water vapour absorption band. Subsidence is indeed associated with drying and a decrease of emission level height (and conversely for ascendance). Under basic physical assumptions, the associated temporal changes in brightness temperature can be quantitatively related to vertical velocity.The retrieval method is evaluated against in situ observations from EUREC4A and OTREC field campaigns that sampled respectively the winter trades and the intertropical convergence zone. Although suffering from significant error bars (+/-4hPa/hr), retrievals are able to reproduce the general temporal evolution and spatial patterns of mid-tropospheric mesoscale vertical motion.The retrieval method is further evaluated using kilometer-scale simulations associated with a radiative transfer code. Basic climatological features are captured such as the distribution of mesoscale vertical velocity or its influence on cloud cover.Despite notable drawbacks, the method is able to provide time-continuous estimations of vertical velocity in clear sky regions of the whole tropical belt at the scale of the pixel of the satellite imager. First results suggest that mesoscale (20-200km) vertical velocity structures are ubiquitous in the tropical free troposphere.These observations could prove valuable for studying dynamical links between deep convection and its environment, especially in association with the new generation of satellites, that will provide measurements of in-cloud convective mass flux and clear-sky time-continuous water vapour and temperature profiles.
Global distribution of estuarine dams and their sedimentological impact
Authors: Lee Guan-hong , Jung Nathalie , Figueroa Steven , Dellapenna Timothy , Chang Jongwi
Published: February 2023

Estuarine dams are dams constructed within the salt or tidal intrusion limits of estuaries for securing freshwater resources or flood control. In this work, we deal with the global distribution of estuarine dams and their sedimentological impact on estuaries. Approximately 10 percent of all estuaries we analyzed (about 2400 estuaries for which river mouth width is greater than 90 m) were affected by estuarine dams and direct human modifications are responsible for more than 1,000 km2 of the observed estuarine surface area loss worldwide. Our field and numerical studies revealed that regardless of estuarine type, estuarine dams amplified the tidal range and reduced the tidal currents. The estuarine turbidity maximum moved seaward, and the suspended sediment concentration tended to decrease. While the morphologic changes depended on the estuarine type, the surficial sediment texture shifted to being muddier for all types. This work is one of the first to show the global extent of estuaries of an estuarine dam and their systematic effects on estuarine sedimentary processes.
A theory for mega-dyke propagation as driven by hotspot topography.
Authors: Davis Timothy , Katz Richard
Published: February 2023

How can mega-dykes propagate hundreds of kilometres laterally through the crust? These blade-shaped dykes are enormous geological structures characterised by widths up to 100 metres. Ernst and Baragar (1992) showed that mega-dykes propagate away from a point at the centre of the dyke swarm. The magma for such dykes is believed to originate from a hotspot impinging on the base of the lithosphere, and this process typically precedes rifting events (Ernst, 2001; Srivastava et al., 2019). Current models do not adequately explain the mechanisms driving the propagation and termination of mega-dykes. We hypothesise that mega-dyke propagation is driven by the gradient in gravitational potential energy associated with the topography of a hotspot swell.We present an analytical model linking the length of mega-dykes to the dimensions of a topographic swell above a hotspot. Our model accounts for various energy sources, including magma-source pressure and gravitational potential energy, and energy sinks such as viscous dissipation, elastic wall-rock deformation, and fracturing at the dyke tip. We define the ground surface deformation above a hotspot using an analytical model (Morgan, 1965) and demonstrate, in this context, that the dyke width scales with distance from the magma source. The final dyke length is computed by finding the point at which the sum of energy sources becomes less than the energy sinks. Furthermore, we explore the trade-offs between parameters controlling the swell size and the final length of a mega-dyke. We tentatively apply our findings to observed mega-dyke swarms and investigate the hot-spot sizes required to produce the observed lengths of these structures.ReferencesErnst, R.E. and Baragar, W.R.A., 1992. Evidence from magnetic fabric for the flow pattern of magma in the Mackenzie giant radiating dyke swarm. Nature, 356(6369), pp.511-513. doi:10.1038/356511a0Ernst, R.E., 2001. The use of mafic dike swarms in identifying and locating mantle plumes. Geological Society of America Special Papers, 352, p.247-265. doi:10.1130/0-8137-2352-3.247Morgan, W.J., 1965. Gravity anomalies and convection currents: 1. A sphere and cylinder sinking beneath the surface of a viscous fluid. Journal of Geophysical Research, 70(24), pp.6175-6187. doi:10.1029/JZ070i024p06175Srivastava, R.K., Ernst, R.E. and Peng, P. eds., 2019. Dyke swarms of the world: A modern perspective. Springer Geology. doi:10.1007/978-981-13-1666-
How can elevated CO2 (eCO2) affect the vegetation structure of a mature evergreen Eucalyptus woodland – results from the Eucalyptus Free-Air CO2 Enrichment (EucFACE) experiment in Australia
Authors: Pisek Jan , Řezníčková Ladislava , Adamson Kairi , Ellsworth David
Published: February 2023

Leaves form the primary interface between plant physiology, CO2 in the atmosphere and energy (light). Plant productivity (i.e. carbon (C) gain) is primarily determined by the amount of leaf area, leaf orientation and distribution in space. Not much attention has been paid to possible changes in leaf orientation and distribution with elevated CO2 (eCO2), but its effect on plant growth could alter the proportions of sunlit and shaded leaf areas and feedback on carbohydrate available for further growth. We report on first measurements of leaf inclination angle distribution, foliage clumping in a native evergreen Eucalyptus woodland - the EucFACE experiment in Western Sydney, New South Wales, Australia - in ambient CO2 and exposed to +150 ppm elevated CO2 (eCO2). We found that a spherical leaf angle distribution, a common assumption in ecosystem modeling, was not an appropriate supposition for present species (Eucalyptus tereticornis Sm.; Eucalyptus amplifolia Naudin) at this site. Our measurements of leaf inclination angles from imagery indicated an erectophile, highly skewed unimodal leaf inclination angle distribution function. We conclude that despite the measured steeper angles under eCO2 concentrations, the leaf angle change is not significant and falls within the expected natural variability and uncertainties connected with the measurement method. The lack of a clear response of leaf orientation and foliage clumping to eCO2 concentration indicates that the previously produced datasets of leaf inclination angles and foliage clumping maps with Earth observation data may be suitable while modelling carbon and water cycles under climate change.
Flood Simulation and Population Impact Analysis of Short-Duration Intense Rainfall in Urban Area
Authors: Wei Hsiao-Ping , Su Yuan-Fong , Chang Chih-Hsin , Yeh Keh-Chia
Published: February 2023

A report from World Bank in 2022 reveals that about 1.81 billion people (23% of the world population) are directly exposed to flood with depths greater than 0.15 meters. In this study, we evaluate the impact of extreme rainfall events on population in urban areas in Taiwan using SOBEK models. The validation results of the SOBEK models are promising with photos collected from social media for historical storm events. To further assess the impact of extreme rainfall events, we used design rainfall with hourly rainfall of 80mm/hr, 90mm/hr, and 100mm/hr derived from Simple Scaling Gaussian Markov (SSGM) method for single rainfall gauge within major urban area. These results are provided for disaster prevention authority to reinforce the flooding management in urban area.
Distribution and characteristics of glaciokarst on the island of Gotland, Baltic Sea - its role on groundwater recharge and sensitive wetland ecosystems
Authors: Erlström Mikael , Dahlqvist Peter , Mild Krister , Sopher Daniel , Martinsson Magnus , Glimskär Anders , Jacobson Anders , Holgersson Björn , Lundberg Frans , Léven Jakob
Published: February 2023

 Glaciokarst is widespread in the Silurian carbonate bedrock on the Island of Gotland. Grikes and limestone pavements are the most common karst features. Although, less well documented, caves and subsurface channels also contribute to the complex hydrogeology in the bedrock. The karst is interpreted to have been formed, primarily, before the Pleistocene when the landscape was covered with acidic organic soils. Glacial erosion and postglacial karstification have also played significant roles in sculpturing the epikarst morphology we see today. The study presents quantitative and qualitative characterization of karst within several pilot areas on the island of Gotland. High resolution aerial photographs were acquired over the pilot areas using a drone. These images were then analysed in GIS-software to provide a statistical evaluation of length, width, and relative area with karst. As well as providing a statistical understanding of the occurrence and geometry of karst, the results also help to clarify the impact of karst on the sensitive and limited groundwater resources on Gotland. Since a large part of the carbonate bedrock surface is barren or covered by thin quaternary deposits the epikarst provides important pathways for the percolation of meteoric water and recharge to the groundwater. It also locally provides guided pathways for surface runoff. Furthermore, the study demonstrates that the presence of karst often is in conjunction with sensitive ecosystems such as temporary wetlands. Extensive development of grikes and limestone pavements also provide conditions for periodically hanging aquifers, which not only promotes groundwater recharge but also the formation of unique habitats for a variety of often threatened ecosystems. This study, which includes both biologists and earth scientists highlights the importance of the identification of catchment areas and mapping of karst. It also emphasises that investigations into the hydrogeology (including aspects such as groundwater recharge, surface runoff and subsurface transport pathways) is essential for a better understanding of wetland dynamics and their protection. The presence of karst and spreading of contaminations in the ground is also discussed. The work summarizes early results from a collaboration between authorities working with Natura 2000 karst habitats and geological classification and mapping of karst.
Impact of tropical eastern Pacific warming bias on Caribbean climate
Authors: Brotons Blanes Marta , Haarsma Rein , Bloemendaal Nadie
Published: February 2023

During the last decades, CMIP5 models simulate a warming trend in the tropical eastern Pacific that has not been present in observations (Seager et al., 2019). Associated with this, the Walker circulation has experienced a westward migration while CMIP5 models simulate an eastward migration. This mismatch is still present in CMIP6 models and might affect climate projections worldwide. In the Caribbean region, CMIP6 models project a strong drying at the end of the 21st century. El Niño-like changes in the Walker circulation are the dominant teleconnections driving the Caribbean drying. The models that project a strong Caribbean drying also simulate generally a strong equatorial eastern Pacific warming trend over the recent decades. Thus, the mismatch between observed and simulated warming trends over the equatorial eastern Pacific questions the reliability of the Caribbean precipitation projections. The warming bias might also have implications for tropical cyclones’ projections in the Atlantic and Pacific through the effect of vertical wind shear, which is related to shifts in the Walker circulation. In addition, the double Intertropical Convergence Zone (ITCZ) bias might be influenced by the mismatching trends. The strong influence of El Niño-Southern Oscillation (ENSO) dynamics on the world’s climate demands more in-depth studies addressing the drivers of the Walker circulation and the equatorial Pacific warming bias.
Quantification and characterizations of plastic debris ingested by sea turtles in Korean waters
Authors: Hong Sang Hee , Moon Yelim , Han Gi Myung , Shim Won Joon , Ha Sung Yong , Kim Il-Hoon , Lee Hae-Rim
Published: February 2023

Global production of plastics has steadily increased since 1950s. As a result, plastics are the most abundant type of marine debris on seafloor and coastal beach, and the prevalence of marine debris has detrimental impact on marine wildlife. The Convention on Biological Diversity (CBD, 2012) estimated that over 80% of adverse environmental impacts on marine life are associated with plastic debris. It is important to build up information on the amount and characteristics of plastic debris that damage marine species to devise strategies and set priorities to reduce their adverse impacts on marine life. This study investigated plastic debris ingested by sea turtles stranded, floating, or by-captured from 2012 to 2022 in the Korean coastal waters. The quantity, shape, color, size, origin, and polymer type of plastic debris (> 1 mm) ingested by sea turtles were analyzed after being sorted from gastrointestinal (GI) tract of 71 turtles: 41 loggerheads, 24 greens, 3 leatherbacks, 2 olive ridleys, and 1 hawksbill turtle. We found a very high frequency of occurrence of plastic debris in GI tract of sea turtles; 100% for greens, 83% for loggerheads, 67% for leatherbacks, 50% for olive ridleys, and 100% for hawksbill. The overall amount of plastics were in the range of 0－1.31 g/kg turtle (0－229 pieces/turtle). The ingested debris tended to be films and fibers (> 74%), light in color (white and transparent; > 60%), and light polymers (polyethylene, polypropylene, polypropylene[poly(ethylene:propylene)], expanded polystyrene; > 90%). Single-use or fishery-related plastics such as filmed packaging, plastic bags, twine, net, and rope were frequently found. Some debris were labeled with Korean (n=14), Chinese (n=10), English (n=2), and Vietnamese (n=1). The shape and origin of ingested debris varied between loggerhead and green turtles. Green turtles ingested commonly fibers (47%) such as rope, twine, and net. Conversely, loggerheads ingested frequently films (45%) such as plastic bag, and packaging. The difference in ingested plastics between greens and loggerheads may be related to feeding habit and geographical range of movement of each species. This study implies that sea turtles inhabiting around the Korean waters are severely affected by marine plastic debris, and that waste management of single-use and fishery-related plastics should be the top priority to effectively reduce the adverse impact of plastic debris on sea turtles.
IAQMS-street v2.0: a two-way coupled regional-urban–street-network model system for Beijing, China
Authors: Wang Tao , Li Jie , Kim Youngseob , Wang Zifa
Published: February 2023

Owing to the substantial traffic emissions in urban areas, especially near road areas, the concentrations of pollutants, such as ozone (O3) and its precursors, have a large gap with the regional averages and their distributions cannot be captured accurately by traditional single-scale air-quality models. In this study, a new version of a regional-urban-street-network model (IAQMS-street v2.0) is presented. An upscaling module is implemented in IAQMS-street v2.0 to calculate the impact of mass transfer to regional scale from street network. The influence of pollutants in street network is considered in the concentration calculation on regional scale, which is not considered in a previous version (IAQMS-street v1.0). In this study, the simulated results in Beijing during August 2021 by using IAQMS-street v2.0, IAQMS-street v1.0, and the regional model (NAQPMS) are compared. On-road traffic emissions in Beijing, as the key model-input data, were established using intelligent image-recognition technology and real-time traffic big data from navigation applications. The simulated results showed that the O3 and nitrogen oxides (NOx) concentrations in Beijing were reproduced by using IAQMS-street v2.0 both on regional scale and street scale. The prediction fractions within a factor of two (FAC2s) between simulations and observations of NO and NO2 increased from 0.11 and 0.34 in NAQPMS to 0.78 and 1.00 in IAQMS-street v2.0, respectively. The normalized mean biases (NMBs) of NO and NO2 decreased from 2.67 and 1.33 to -0.25 and 0.08. the concentration of NOx at street scale is higher than that at the regional scale, and the simulated distribution of pollutants on regional scale was improved in IAQMS-street v2.0 compared with that in IAQMS-street v1.0.  We further used the IAQMS-street v2.0 to quantify the contribution of local on-road traffic emissions to the O3 and NOx emissions and analyze the effect of traffic-regulation policies in Beijing. Results showed that heavy-duty trucks are the major source of on-road traffic emissions of NOx. The relative contributions of local traffic emissions to NO2, NO, and O3 emissions were 53.41, 57.45, and 8.49%, respectively. We found that traffic-regulation policies in Beijing largely decreased the concentrations of NOx and hydrocarbons (HC); however, the O3 concentration near the road increased due to the decrease consumption of O3 by NO. To decrease the O3 concentration in urban areas, controlling the local emissions of HC and NOx from other sources requires consideration.
Subduction of bathymetric irregularities along active margins: insights from numerical modeling
Authors: Manea Vlad Constantin , Manea Marina , Petrescu Lucian
Published: February 2023

Oceanic plates are far from homogeneous, and a large number of bathymetric discontinuities such as seamounts of different sizes are transported along by plate motion towards the mid ocean trenches and beyond. Seamounts currently colliding with plate margins show a major role in shaping the forearc morphology, and several studies even suggest that they might be related with seismicity. However, it is not clear what happens after seamounts are subducted, they can be accreted to the forearc, carried down into the subduction zone and recycled into the deep mantle, or a mix of the two scenarios. Using high-resolution two-dimensional thermomechanical numerical simulations, we investigate subduction processes of oceanic plates with a heterogeneous structure marked by a series of basaltic seamounts arranged in a chain like structure. We solve the 2D momentum, continuity and energy equations with the finite differences coupled with PIC (particle-in-cell) method. Our models also incorporate a depth-dependent, realistic non-Newtonian visco-elasto-plastic rheology, and plasticity is implemented using a yield criterion which limits the creep viscosity. Preliminary results show that initially seamounts preserve they structure when impacting with the trench. Their integrity is partially conserved until they subduct to a depth of about 25-30 km when they finally start to succumb to the great deformations and stresses along the slab interface. We observed that the lower part of the seamount continuously deforms and amalgamates along the slab interface. The upper part is detached and incorporated into the forearc structure. The subsequent seamounts that trail the first seamount, follow the same deformation pattern, and the top of them are maintained in the highly deformed forearc region. Our preliminary modeling results confirm that seamount subduction represent a key tectonic process that influences on a long-term time scale the structure and evolution of subduction zones.
Representing storylines with causal networks to support decision making
Authors: Kunimitsu Taro , Baldissera Pacchetti Marina , Ciullo Alessio , Sillmann Jana , Shepherd Theodore G. , Taner Ümit , van den Hurk Bart
Published: February 2023

Physical climate storylines, which are physically self-consistent unfoldings of events, have been powerful tools in understanding regional climate impacts. We show how embedding physical climate storylines into a causal network framework allows user value judgments to be incorporated into the storyline in the form of probabilistic Bayesian priors, and can support decision making through inspection of the causal network outputs.We exemplify this through a specific storyline, namely a storyline on the impacts of tropical cyclones on the European Union Solidarity Fund. We outline how the constructed causal network can incorporate value judgments, particularly the prospects on climate change and its impact on cyclone intensity increase, and on economic growth. We also explore how the causal network responds to policy options chosen by the user. The resulting output from the network leads to individualized policy recommendations, allowing the causal network to be used as a possible interface for policy exploration in stakeholder engagements. 
Origin and transformation of organic aerosol at three background sites in Central Europe
Authors: Lhotka Radek , Pokorná Petra , Vodička Petr , Zíková Naděžda , Ondráček Jakub , Mbengue Saliou , Arora Shubhi , Poulain Laurent , Herrmann Hartmut , Schwarz Jaroslav , Ždímal Vladimír
Published: February 2023

The source apportionment of organic aerosols (OA) in background locations is one of the important issues in contemporary air quality protection. A better understanding of the atmospheric aerosols origin and their source apportionment in different locations is essential for improving air quality.Measurements of non-refractory PM1 (NR-PM1) were simultaneously performed during winter (1st February – 10th March) and summer (1st July – 20th August)  2021 at three background sites, National Atmospheric Observatory Košetice (N 49°35′, E 15°05′; 534 m a.s.l.) and Frýdlant (N 50°94′, E 15°07′; 366 m a.s.l.) in Czech Republic, and Melpitz (N 51°32', E 12°56'; 86 m a.s.l.) in Germany. Each site was equipped with an Aerosol Mass Spectrometer: a ToF- Aerosol Chemical Speciation Monitor (ToF-ACSM) at Košetice, a Compact Time-of-Flight Aerosol Mass Spectrometer C-ToF-AMS) at Frýdlant, and a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) at Melpitz.A Positive Matrix Factorization (PMF) with multi-linear engine (ME-2) using Source Finder (SoFi) (Canonaco et al., 2013) was applied to OA data sets to separate OA into different factors in terms of their mass spectra and time series. Four sources of OA were identified for the winter season. Three of these sources, hydrocarbon-like organic aerosol (HOA), biomass burning organic aerosol (BBOA), and coal combustion organic aerosol (CCOA), belong to the primary sources. The last factor, designated oxidised organic aerosol (OOA), belongs to the secondary sources. Four sources of OA have also been identified for the summer season. Two of these sources were designated as primary sources (HOA and BBOA) and two as secondary sources, more oxidized organic aerosol (MO-OOA) and less oxidized organic aerosol (LO-OOA). Acknowledgements:This work was supported within a German-Czech cooperation in the TRACE project funded by the GACR under grant 20-08304J and by DFG under grant 431895563, also by the MEYS of the Czech Republic under grants ACTRIS-CZ LM2018122 and ACTRIS-CZ RI (CZ.02.1 .01 / 0.0 / 0.0 / 16_013 / 0001315), and European Union's Horizon 2020 research and innovation program ACTRIS IMP (871115). Reference:Canonaco, F., Crippa, M., Slowik, J. G., Baltensperger, U., Prévôt, A. S.: SoFi, an IGOR-based interface for the efficient use of the generalized multilinear engine (ME-2) for the source apportionment: ME-2 application to aerosol mass spectrometer data, Atmos. Measur. Tech., 6(12), 3649-3661, 2013.
The global land water storage data set GLWS 2.0: assimilating GRACE and GRACE-FO into a global hydrological model
Authors: Gerdener Helena , Kusche Jürgen , Schulze Kerstin , Döll Petra , Klos Anna
Published: February 2023

The satellite mission Gravity Recovery And Climate Experiment (GRACE) provided and its successor GRACE-FollowOn (GRACE-FO) provides a great opportunity to derive observations of the global water cycle from space. The missions have contributed and largely increased our knowledge about various hydrological processes on Earth, for example the melting of glaciers in Greenland or groundwater depletion in India. Nonetheless, the spatial resolution of about 300 km, missing months in the time series and the multi-month gap between GRACE and GRACE-FO complicate or even impede the usage in some applications. Further, separating single storage information, e.g. groundwater, from the GRACE/-FO derived total water storage anomalies (TWSA) is still difficult.In recent decades, data assimilation techniques were used to downscale and disaggregate the GRACE/-FO TWSA, however, to our knowledge they focus on hydrological instead of geodetic applications, only a few assimilate GRACE/-FO TWSA on a global scale and open access is rare. Therefore, we provide the new Global Land Water Storage (GLWS2.0) data set that offers total water storage anomalies on a 0.5° monthly grid covering the global land except Greenland and Antarctica for the time period 2003 to 2019 without missing months and the GRACE/GRACE-FO gap and will soon be publicly available. GLWS2.0 is derived by assimilating GRACE and GRACE-FO TWSA into the WaterGAP model using the Ensemble Kalman Filter considering uncertainties.We contrast the GLWS2.0 data with the GRACE/-FO observations and the model simulations in the spatial domain via linear trends, annual amplitudes and non-seasonal TWSA and in the spectral domain via degree variances, c20 coefficients and other representation of spherical harmonics. Worldwide, 1030 GNSS stations are used to validate GLWS2.0 by analyzing the vertical loading at short-term, seasonal and long-term temporal bands and we find that GLWS2.0 agrees better with GNSS than GRACE/-FO. In addition, a good agreement to another global data assimilation product is found, which assimilates GRACE/-FO TWSA into the Catchment Land Surface Model by NASA’s Goddard Space Flight Center.
Assessing future water availability using HydroRiver – A use case in the climate adaptation digital twin of the Destination Earth Program
Authors: Chandrasekar Aparna , Marx Andreas , Müller Sebastian , Sharifi Ehsan , Javier Leal Rojas Jeisson , Thober Stephan
Published: February 2023

The Sixth Assessment Report from the Intergovernmental Panel on Climate Change emphasized on the water cycle, and water-related disasters (i.e., water scarcity, droughts, floods) that impact all sectors and regions. Therefore, assessing future water availability is critical to develop mitigation strategies and formulate adaptation policies. While developing relevant information systems, it is critical to ensure the involvement of stakeholders in the field of policy development, communities impacted by future water availability (e.g., agriculture, fisheries, shipping industry), and private industries (e.g., paper and pulp, hydropower) to ensure that information presented can be useful to support decision making. Destination Earth (DestinE) aims to, among other products, to develop – on a global scale – a highly accurate digital model of the Earth to monitor and predict the interaction between natural phenomena and human activities. As part of the European Commission’s Green Deal and Digital Strategy, DestinE will contribute to achieving the objectives of the twin transition, green and digital. High resolution climate simulations (ICON and IFS climate models) are used as meteorological forcings for the mesoscale Hydrological Model (mHM) to produce high temporal (1 hour) and spatial resolution (5 km) streamflow estimates at a global scale. The impact model consists of the mHM model, which includes key hydrological processes e.g., run-off, soil moisture dynamics, fast and slow interflow processes to estimate river discharge. The application prototype will provide: 1) co-designing the indicators and indices as well as application functionalities together with relevant stakeholders. 2) downscaling of the essential climate variables 3) providing bias correction for the climate variables 4) running the mHM model under various climate scenarios. In addition, the application will receive data through direct streaming from the climate simulations thus ensuring interactivity of the application for the users. During the development phase of the DestinE digital twin, the climate simulations used in the current work are taken from the results of the NextGEMS project. They have been used to provide a proof of concept for the mHM model, and provide initial results for stakeholder engagement, and enable early involvement of stakeholders in the co-design of relevant applications.
Investigating the relationship between particle size of suspended sediments and optical sensor turbidity readings
Authors: Kuzmanić Tamara , Lebar Klaudija , Klun Mateja , Rusjan Simon
Published: February 2023

Optical sensors are widely used for turbidity measurements in suspended sediment concentration studies. When conducting continuous measurements of turbidity in the field with optical sensors, results are determined according to the calibration curve (relationship between suspended sediment concentration and turbidity readings from the optical sensors). The calibration curve is developed based on the samples of the material present in and/or around the investigated stream. The concentration data are useful in water-quality-related investigations as well as for evaluating the amounts of transported (flushed, eroded) material from the catchments as suspended load. The amounts and particle sizes of transported material depend on the hydrological conditions. Usually, the particles’ size is not directly considered when developing the calibration curve. However, different particle sizes of the material from the same study site can result in different turbidity readings. Taking into account one general calibration curve for suspended sediment concentration determination can lead to misestimation of the transported material amounts. Here, the results of turbidity sensor calibration for different particle size classes are presented. Additionally, the uncertainty of the suspended material concentrations due to this effect is estimated. Further, we show how different calibration curves affect the assessment of the amount of the transported suspended load from the selected experimental catchment.
Past and future changes toward earlier timing of streamflow over Pakistan from bias-corrected regional climate projections (1962–2099)
Authors: Ali Shahid , Jonghun Kam , Byeong-Hee Kim Kim , Taimoor Akhtar
Published: February 2023

Streamflow has fluctuated seasonally in Pakistan and surface warming has caused its seasonal change, sometimes resulting in a lack of water resources for agriculture. However, little is known about how the seasonal changes in the hydrologic regimes over Pakistan has been and will be persisted. Using daily streamflow records from four gag stations data and bias-corrected hydrological projections, this study assessed the past and future changes in streamflow timing along four major river basins of Pakistan (Upper Indus, Kabul, Jhelum, and Chenab). First, we simulated the VIC-river routing model to generate past and future daily streamflow data forced by simulated daily surface and base runoff data from six CORDEX-South Asia regional climate models (1962–2099). Second, we corrected minimum and seasonality bias in simulated daily streamflow data against the daily observational records. Third, we calculated half of the annual cumulative streamflows (HCSs) and center-of-volume dates (CVDs) of observed and bias-corrected simulated streamflow data to quantify seasonal changes in the hydrologic regime. Except for the Chenab River basin, observational records revealed a significant decreasing trend in CVD (i.e., an earlier onset of the wet season) over Pakistan basins over 1962–2019. Bias-corrected hydrologic projections revealed a decrease in CVD of 4.2 to 6.3 days across the four study river basins over the overlapped period. The average decrease in CVDs ranged from 5 to 20 days and 11 to 37 days in the near future (the 2050–2059 average) and the far future (the 2090–2099 average), respectively. We found that the hydrologic responses of all four basins are diverse with different magnitudes of CVDs despite a similar magnitude of near-surface temperature across the basins, highlighting the need for basin-specific water resources management and climate change adaptation policies.