bluuebunny/crossref_metadata_2025 huggingface dataset:
Voxel-based Density Models for Accurate Gravitational Field Computation
Authors: Haser Benjamin , Andert Thomas , Förstner Roger
Published: March 2024

Asteroids and moons are promising targets for physical space exploration. The use of physically-based simulations within a virtual environment for (deep) space missions can significantly benefit the testing and validation of guidance, navigation, and control algorithms. This approach offers advantages in terms of cost and time efficiency. Especially for orbit propagation and landing maneuvers, information about the gravitational field is crucial. However, several factors contribute to the complexity of this task, such as limited information available about the inner structure of celestial bodies. The lack of detailed knowledge about their shapes further adds to the challenge.This study presents a voxel-based mass concentration (MASCON) method to model detailed and realistic density distributions, enabling accurate gravity field determinations. We chose a cube with constant density as first case due to the perfect shape reconstruction and the availability of an analytical solution for its gravity field. To validate our results, we calculated the surface gravity and compared it with the analytical solution, ensuring the accuracy of our calculations. Furthermore, the surface gravity is derived for different resolutions and compared against other state-of-the-art methods like the polyhedral method that provides a closed-form analytical solution of the gravity field for homogeneous density. The other two methods for validation also use a MASCON approach, one utilizing polydisperse sphere packing and another with MASCON represented in spherical coordinates. The relative errors of the gravitational acceleration between the four methods will be evaluated for a cube and sphere, with homogeneous density.The second aspect of this study was to create a tool that generates realistic density distributions. We are able to successfully reproduce natural environments by placing body-specific restrictions on three-dimensional Perlin noise with additional normalization. The simulator can add the following structural features to the density distribution: an arbitrary number of centralized or decentralized shells, with varying thickness and densities, anomalies of arbitrary size and shape, only restricted by its maximum permille of the body's volume. Furthermore, we implemented different normalization techniques to keep the mass of all generated bodies fixed. Our results show that the tool can generate realistic density distributions and calculate the corresponding gravitational field correctly. The data generated here is used to train Machine Learning and Deep Learning algorithms for gravity inversion. 
Parameter estimation of GNSS real-time satellite clock error and its application in PWV retrieval
Authors: Li Xiaoming , Li Haojun
Published: March 2024

GNSS real-time PPP have been demonstrated to be applicable to PWV retrieval effectively. The GNSS real-time satellite clock error is one of the essential factors that affects the accuracy of PPP, and its estimation method is usually considered to be white noise random processes which ignore the stable periodic variation characteristics of GNSS atomic clocks. In addition, the GNSS satellite clock offsets real-time service have low timeliness due to the time consumption of clock offsets series estimation and fitting of quadratic polynomial coefficients, even when communication is interrupted for a short period of time, RTS cannot be obtained. Thus, we developed a method that directly estimate satellite clock model coefficients simultaneously with tropospheric wet delay, receiver clock error, and phase ambiguity parameters from global GNSS code and phase measurements. The difference from traditional RTS is that the satellite clock model coefficients can be delivered to PPP users once estimated process is completed without the step of fitting. Several satellite clock models composed of polynomial and harmonic-based functions are applied to the parameter estimation of real-time satellite clock error, we compared the accuracy of estimated model parameters to IGS real-time satellite clock offsets, and discussed its performance of PPP positioning and PWV retrieval. Finally, we simulated the performance of proposed parameter estimation scheme of satellite clock error and PWV retrieval for different update interval in case of communication interruption for several minutes.
Dynamic rupture process of the 2018 Hokkaido Mw6.6 earthquake, Japan
Authors: Zhang Wenbo , Xie Zhangdi
Published: March 2024

The Mw6.6 earthquake occurred in the Higashi-Geizen area of Hokkaido, Japan, on September 5, 2018, at a depth of 37 km, which exceeds the depth of the brittle-ductile boundary between the crust and the upper mantle and produces strong damage at the surface. In order to study the seismic tectonics of the source region of the Hokkaido earthquake and the physical mechanism that generates strong ground motions, this paper investigated the dynamics of this earthquake, and attempts to invert the dynamic rupture process based on a kinematic source model. First, the kinematic model of the Hokkaido earthquake was used to analyze and calculate the shear stresses on the fault plane, and it was found that the rupture process basically followed the slip-weakening friction law. Based on this result, an initial dynamic source model was built. Then the dynamic rupture process of the earthquake was inverted by the trial-and-error method. Our results show that the dynamic source rupture process of the Hokkaido earthquake was dominated by strike-slip in the rupture initiating area, and at first propagated toward NE and then toward SW. Finally propagated toward the up-dip direction of the fault plane, producing thrust rupture at the bend of the fault. At the location of thrust rupture, the slip rate and total slip reach their maximum values. Combined with the analysis of kinematic and dynamic inversion results, it is inferred that the region is a strong motion generation zone (SMGA). The strong-ground motions generated from the SMGA mainly caused this earthquake disaster.
Opportunities and challenges for agricultural catchments water management under current and future extreme weather events to support crop water requirements
Authors: Malmquist Louise , Barron Jennie
Published: March 2024

potential impacts for waterrelated agricultural - (soil moisture deficit/surplus, evapotranspiration deficit) and hydrological hazards (surplus/deficit of landscape water storage/flow/recharge in streams, waterbodies and aquifers). Furthermore, compound events of meteorological and hydrological extreme events can lead to crop damage, yield quantity- and quality reduction  that might not have occurred as response for the individual weather events (Lesk et al., 2022). Wet and dry spells have already altered  across Europe (e.g. Fischer and Knutti, 2016; Lorenz et al., 2019), with changes of both wet- and dry spell duration and timing in northern Scandinavia (Breinl et al., 2020; Grusson and Barron, 2021),    with measurable effects on runoff components for basin scale (e.g. Teutschbein et al., 2022). Understanding the response to weather events and occurrence of agrometeorological extreme events is a key step to further analyse effects of the resilience, adaptation capacity and  mitigation requirements towards hydrologic characteristics at field- landscape and catchment scale (e.g. Miralles-Wilhelm et al., 2022). Though, the less explored spatial-, temporal-, and magnitudinal occurrence of and landscape buffering capacity towards agricultural droughts and floods in current- and future climate is an important knowledge gap needed to be highlighted, to evaluate the efficiency of measures to ensure sufficient water availability for agricultural production.
Here we studied catchment hydrological response to weather events from bottom-up perspective (e.g.Vogel et al., 2021). We used crop yield as the impact parameter and agricultural- and hydrological drought and flood hazards  as indicators and pre-occurring weather events as climatic drivers (Zscheischler et al., 2020). We aim to explore how catchment landscape characteristics can buffer against high- and low water availability to sustain crop productivity under current and future climate change? What are the differences between catchments impacts to sustain healthy water resources and yield levels?
We present the water balance in four meso-scale agricultural catchments in Sweden in the hydrological model SWAT+ under current extreme events and weather data with scenarios of temperature and precipitation change in line with IPCC AR6 scenarios. Our results show the effect from existing water retention measures in landscapes to reduce hazardous events of soil moisture (drought and saturation conditions) and streamflow in relation to crop yield.  We discuss the challenge of assessing agriculturally dominant landscape water balances with relevant precision for water and land resource management at mesoscale catchments
A plastic tipping point: The influence of biofouling on the settling orientation of plastics.
Authors: Lofty James , Ouro Pablo , Wilson Catherine
Published: March 2024

The settling velocity of a plastic particle is a crucial descriptor for plastic transport in rivers. When a plastic particle is introduced into the riverine environment, the plastic’ surface provides a medium that enables the attachment, accumulation and growth of microorganisms, known as biofouling. While the settling velocity has been extensively studied for pristine plastics, the influence of biofouling on settling velocity and transport dynamics of plastics needs to be fully understood. Biofouling can alter a plastic particle's size, shape, weight, and buoyancy, potentially leading to an increase in settling velocity of up to 130% compared to the same pristine plastic. However, the effect of an uneven particle weight distribution, caused by heterogeneous biofilm growth, on the plastic’s settling orientation, vertical trajectory and subsequent settling velocity has yet to be investigated. This study aims to quantify the impact of biofouling on the settling orientation of a plastic particle and describe its subsequent effect on settling velocity and pattern. To achieve this, we conducted experiments using a synchronised multi-camera setup and a three-dimensional particle reconstruction to characterise particle trajectories and settling orientations. Two sets of the same negatively buoyant PTFE plastic fragments and spheres were tested, namely: i) pristine plastics, and ii) plastics subjected to biofilm colonisation in laboratory conditions. The tested plastics were fragments in sizes 1 x 10 x 10 mm and 1 x 20 x 10 mm, as well as spheres with a diameter of 5 mm. These experiments will have significant implications for the description of the settling velocity of plastics which will aid in informing future field campaigns aimed at quantifying riverine plastic transport.
Towards a 16-year surface reanalysis of air quality over North America using EnOI
Authors: Ménard Richard , Cossette Jean-Francois , Abu James , Deshaies-Jacques Martin , Pentcheva Nedka
Published: March 2024

The technique of EnOI has been used to produce operational surface air quality analysis at Environment and Climate Change Canada since 2022 (a simpler assimilation technique was used from 2003 to 2012).  We have adopted an ensemble modeling of the background error covariance, based on air quality forecasts of GEM-MACH over the previous two months.  The error correlations obtained from these ensembles are anisotropic and non-homogeneous, capturing the effects of topography, large water surfaces, valleys, major highways, and local sources, but are not as such flow-dependent.  Error variances are also modeled using empirical relationship obtained from innovation covariance and concentrations.  Other parameters of the analyis system are estimated minimizing the analysis error variance as perceived using cross-validation.  This analysis scheme has distinct computational advantage as it does not require additional forecasting costs, and yet provide an accurate and optimized analysis using anisotropic non-homogeneous correlations.  In this talk we will present the methodology and some result of operational implementation.  In reanaysis mode it is even more accurate than the operational implementation.  Because it is computationally fast, it allows easily for reanalyses over decades.  Early results of a 16 year reanalysis (2001-2017) will be also be presented. 
The global interdependence patterns of extreme-rainfall events
Authors: Su Zhen , Meyerhenke Henning , Kurths Jürgen
Published: March 2024

As a powerful data-driven technology, the complex network paradigm has contributed significantly to the studies of spatio-temporal patterns of climate phenomena at different scales, such as El Niño–Southern Oscillation, Indian Ocean Dipole, and monsoon. In this work, we study the global extreme-rainfall patterns, which can potentially be used to improve the predictability of extreme events. The idea is to identify regions of similar extreme-rainfall patterns. For this, we propose a network-based clustering workflow which includes unsupervised learning. More precisely, this workflow combines consensus clustering and mutual correspondences. By applying this workflow to two satellite-derived precipitation datasets, we identify two main global interdependence structures of extreme rainfall, during boreal summer. These two structures are consistent and robust. From a climatological point view, they explicitly manifest the primary intraseasonal variability in the context of the global monsoon, in particular, the “monsoon jump” over both East Asia and West Africa, and the mid-summer drought over Central America and southern Mexico. We highlight the advantage of network-based clustering in (i) decoding the spatio-temporal patterns of climate variability and in (ii) the intercomparison of these patterns, especially regarding their spatial distributions over different datasets.
Freedom and Responsibility: the Ethics of Academic Researchers’ Public Advocacy
Authors: Guilyardi Eric
Published: March 2024

Academic researchers have long been advocates of various causes in the public arena; their public advocacy to take normative positions regarding various moral, political or social issues is not new. Today, however, in the face of the many challenges facing our society, the question of researchers' public positions, particularly in relation to the environment and climate change, is being raised anew. A number of climate scientists are committed in a variety of ways, from signing op-eds to participating in the work of NGOs or think tanks, supporting legal actions or writing blog posts. In addition, the development of traditional and social media has significantly increased the public exposure of these researchers. At the same time, serious questions are being raised within the research community. Many of its members are debating the ways in which researchers can engage in such public advocacy, its advisability, and even its very principle. However, these debates are currently taking place in informal settings and, given the extensive individual experience of a number of colleagues, it is probably time to engage in this discussion in a more collective and organised way, as is done in other research communities.Here are some examples of questions that might be discussed. How can researchers engage in public advocacy safely and responsibly? What is the role of the scientist versus the expert versus the citizen versus the activist? Can a researcher be neutral when taking a public stance? What is the risk of appearing naive, manipulated or irrelevant? How should researchers deal with vested interests and private actors? Should the climate community research geoengineering? For whom should researchers develop climate services?Because addressing these issues involves a tension between personal values that may go beyond those shared by the scientific community, they are essentially novel ethical questions. Some may be so intimidating that many researchers choose not to engage publicly. Care must therefore be taken to organise the exchange properly, for example by creating safe internal spaces for debate or by inviting experts from other disciplines.The French CNRS Ethics Committee has recently published on opinions on these issues[1], which I will use as a starting point for a broader discussion.
[1]  https://comite-ethique.cnrs.fr/en/comets-opinion-freedom-and-responsibility-academic-researchers-public-advocacy/
Homogenization of observed surface wind speed based on geostrophic wind theory over China from 1970 to 2017
Authors: Zhang Zhengtai
Published: March 2024

The observed surface wind speed (SWS) over China has declined in the past four decades, and recently, the trend has reversed, which is known as SWS stilling and recovery. The observed SWS is vulnerable to changes in nonclimatic factors, i.e., inhomogeneity. Unfortunately, most of the existing studies on the long-term trend of SWS were based on raw datasets without homogenization. In this study, by means of geostrophic wind speed and penalized maximal T test, we conduct a systematic homogeneity test and exploration of the homogenization impact for SWS at over 2,000 stations in China from 1970 to 2017. The results show that the inhomogeneity in the observed SWS over China is detectable at 59% of national weather stations. The breakpoint years are mainly concentrated in the late 1970s, mid-1990s and early 2000s. Overall, 18% of breakpoints are caused by station relocations, and the remaining breakpoints are likely related to anemometer replacement and measurement environment changes that occurred during the mid-1990s and early 2000s. After homogenization, the decreasing trend in SWS during 1970-2017 decreased from -0.15 m/s decade-1 to -0.05 m/s decade-1. The homogenized SWS recovery period advanced from the early 21st century to the early 1990s, which is consistent with the SWS variations, excluding the impact of urbanization around weather stations. The phase change in the Western Hemisphere warm pool (WHWP) might be one of the causes of homogenized SWS recovery.
Monazite age constraint on the Mahakoshal Supracrustal Belt, India
Authors: Mondal Amit , Mallick Smruti Prakash , Pruseth Kamal Lochan
Published: March 2024

The Mahakoshal Supracrustal Belt (MSB) marks the northern margin of the Central Indian Tectonic Zone (CITZ) along which are sutured the northern and southern crustal blocks of India. Monazite U-Th-Pb total ages in the Dudhi granite from a sample at the southern margin of the MSB are reported here. Although the age of the MSB was constrained between 1.8 and 2.2 Ga, a more precise upper age limit of ~2.1 Ga was proposed later. The present sample shows signatures of extensive hydrothermal alteration resulting in the replacement of orthoclase by oligoclase accompanied by precipitation of carbonate and microcrystalline silica. The monazites yield seven age peaks starting from 2053±65 Ma to 1457±39 Ma, suggesting multiple resetting of the ages. The most intense peaks are at 1951±19 Ma (n=29), 1851±20 Ma (n=20) and 1787±25 Ma (n=12), with only three points in the 2053±65 Ma population. Most likely, the Dudhi granite represents partial melting of the basement to the MSB at 2053±65 Ma and constrains the maximum age of the MSB, corroborating the upper age limit suggested earlier.
Carbonate System Changes Within an Evaporating Sea Spray Droplet
Authors: Hendrickson Lucy , Vlahos Penny , Romero Leonel
Published: March 2024

Modeling the air-sea flux of CO2 is a key factor in understanding climate change and predicting its effects. The contribution of sea spray to this flux is highly uncertain yet important for reducing error margins in global estimates. In this work, a modified CO2SYS routine is used to quantify the effect of evaporation on aqueous carbonate reactions in sea spray in order to assess this flux. Factors that affect these reactions are the increasing salinity and temperature changes of the droplet as it evaporates. The size of the droplet is also a determining factor as it affects the time aloft and thus the amount of evaporation and gas exchange that can occur. Using these factors and a number of simplifying assumptions, we model the change in DIC, TA, pCO2 and pH in an evaporating sea spray droplet.
Impact of submesoscale currents on surface waves: the U2H map
Authors: Vanneste Jacques , Villas Bôas Ana B. , Wang Han , Young William R.
Published: March 2024

Ocean turbulence at meso- and submesocales affects the propagation of surface waves through refraction and scattering. This induces spatial modulations in wave energy, with implications for air–sea exchanges, the likelihood of extreme waves, and remote sensing. We develop a theoretical framework that relates modulations in significant wave height (SWH) to the currents that induce them. We exploit the asymptotic smallness of the ratio of typical current speed to wave group speed (which holds for wavelengths above 10 m or so) to derive a linear map – the U2H map – that relates SWH anomalies to the surface current velocity. This map is a convolution, non-local in space but expressible as a product in Fourier space and, crucially, independent of the magnitude of the Fourier vector. The properties of the map show how the SWH anomaly responds differently to the vortical and divergent parts of the currents, and how the anisotropy of the wave spectrum is key to large current-induced SWH anomalies. Analysing the U2H map, in particular for swell-like, highly directional waves enables us to explain a series of earlier numerical observations. We implement the U2H map numerically and test its predictions against  WAVEWATCH III numerical simulations for both idealised and realistic current configurations. Our framework can be straightforwardly extended to relate characteristics of the wave field other than SWH such as Stokes drift to the currents.  
Game based behavioral experiment to characterize behavioral biases in water decisions
Authors: McGiven Lauren , Müller Marc
Published: March 2024

Recent research in behavioral economics has identified a series of cognitive biases, where the decisions made by individuals diverge from the rational choice assumption and expected utility maximization theory. For example,  simplification bias neglects low-probability–high consequence (LP-HC) events because the perceived probability of risk is too low; myopia bias neglects adaptation measures with high upfront costs and long-term benefits in favor of near-term risks; and availability bias neglects LP-HC events until the consequences have had a direct impact. While broadly acknowledged within sociohydrology community, these biases remain poorly characterized and are often excluded from sociohydrological models. We bridge this gap by leveraging a recent web-based computer game, where players make farming decisions — including the purchase of crop insurance — to address hydroclimatic uncertainty in the context of climate change. We deploy the game on the mechanical turk platform to carry out behavioral experiments at a massive scale to understand the conditions under which these three biases emerge in water resources decisions. 
Appraisal and Prognosis: Towards Projecting the Future Changes in Urban Extreme Temperature Events over India under Climate Change Scenarios
Authors: Joshi Nitin , Maurya Hardeep , Suryavanshi Shakti , Dubey Amit
Published: March 2024

Global warming results in increase in the intensity and frequency of extreme temperature events across the world. This study used multivariate copula approach to comprehend variations in intensity and frequency of extreme temperature events over 54 urban agglomerations in India. The current study uses the Coupled Model Intercomparison Phase 6 (CMIP6) framework to explore the relationship between temperature intensity duration frequency for 1.5°C, 2°C, and 3°C global warming levels (GWL) over the two time periods, T1(2021-2050) and T2(2071-2100). Using bivariate copulas, we analyse the changes in return estimates for temperature extreme considering 10, 20, 50, and 100-year return periods over 2, 5, and 10-day durations. Amongst various distributions, the lognormal and extreme value distribution appeared as the most suitable distributions to represent duration and temperature intensity, respectively. As far as copula analysis is concerned, the Gumbel-Hougaard copula was found to be most suitable to illustrate the joint behaviour. With respect to base period, more than 60%, 64% and 80% of urban agglomerations report an increase in the extreme temperature return values under 1.5°C, 2°C, and 3°C GWL respectively. By the end of the century, more than 83% of urban agglomerations will experience an increase in the extreme temperature return values. A significant regional variation has been observed in the percentage change of the return estimates. Cities such as Mysore, Bangalore, Pune, Dharwad, Coimbatore report 9-18% decrease in the extreme temperature return values. Whereas, cities such as Amritsar, Jalandhar, Delhi, Shimla, and Kanpur report 23%-28%, increase in return values. Furthermore, these cities are projected to experience an increase of 30% by the end of the century. The findings highlight the urgent necessity for the implementation of climate change mitigation strategies that are more closely aligned with the objectives outlined in the Paris Agreement. By implementing strategies aimed at limiting global warming, we can effectively alleviate the detrimental impacts and increasing hazards linked to extreme heat events.
Spatial and temporal changes in surface mass balance derived from airborne radio sounding for the plateau area in Dronning Maud Land
Authors: Zuhr Alexandra , Franke Steven , Steinhage Daniel , Jansen Daniela , Eisen Olaf , Drews Reinhard
Published: March 2024

Contrary to the rest of the Antarctic ice sheet, East Antarctica currently gains mass due to an increase in snow accumulation over the last decades. How or if this increase is linked to anthropogenic warming is not yet clear and requires better understanding of the surface mass balance history over the last centuries, and also the dependency of snow accumulation with the local surface slopes across different spatial scales.Here, we present a novel airborne dataset using the multichannel ultra-wideband radar system from the Alfred Wegener Institute in Germany with a decadal vertical resolution for the plateau area in Dronning Maud Land. We assess the spatial and temporal variability of surface mass balance and snow accumulation for the past centuries for an area of ~200,000 km2. With this contribution, we aim to (1) show the potential to use ultra-wideband radar systems to reconstruct the recent surface mass balance and accumulation rates in low-accumulation regions, (2) present information on large spatial scales, and (3) discuss potential overlap of interests and/or data in this and/or other areas on the plateau of East Antarctica.
Analyzing the Impact of Space Weather on Stratospheric Dynamics: Insights from Be-7 Cosmogenic Radionuclide Concentration
Authors: Podolská Kateřina , Kozubek Michal , Hýža Miroslav , Šindelářová Tereza
Published: March 2024

The concentrations of the radionuclide Be-7 are reliable indicators of various atmospheric processes, and primarily determined by the solar activity level and space weather conditions. The highest values of cosmic radiation are observed during the solar minima because, at that time the penetrability of the Earth’s and Sun magnetosphere is largest. In our work, we try to contribute to better understanding of the dynamics of processes by associating them with long-term trends of stratospheric temperature dynamics.We investigate mainly the coupling of concentrations of the cosmogenic radionuclide Be-7 in the longitudinal view during the years 1986 – 2023 (time series of activity concentration of Be-7 in aerosols evaluated by the corresponding activity in aerosols on a weekly basis at the National Radiation Protection Institute Monitoring Section in Prague) to space weather parameters (Kp planetary index, disturbance storm time Dst, proton density, proton flux), and stratospheric dynamics parameters (temperature, zonal component of wind, O3, and ERA5 temperatures profiles).We compare Be-7 concentrations during periods of strong solar and geomagnetic storms with periods of low solar activity in the longitudinal view (years 1986 – 2023). On short timescales, solar proton flux 60 MeV induces only small changes of the Be-7 concentration in aerosols in several days. On a long timescale, solar radio flux and disturbance storm time have impact on the Be-7 concentration in aerosols. The Be-7 concentration trend component (TCt) is significantly influenced by the trend of solar activity degree and by variations in the geomagnetic field on this time scale.
Controls on hydrological connectivity in the Lower Oder river and its floodplain 
Authors: Zheng Hanwu , Tetzlaff Doerthe , Freymueller Jonas , Chmieleski Jana , Okujeni Akpona , Soulsby Chris
Published: March 2024

Hydrological connectivity affects many ecological services (e.g., water storage, nutrients deposition, habitat provision) of landscape systems, especially in river-floodplain systems which generally show great variations at different spatial-temporal scales. Here, we present insights from the Oder river-floodplain system in Germany. Multiple potential contributions to flood plain inundation (i.e., from the river, rainfall, and groundwater) make this system complex and understanding the dynamics of connectivity and its controlling factors is still limited which has implication for floodplain management. We used a remote sensing data cube of harmonized Landsat and Sentinel-2 imagery to derive a temporally dense, 8-year NDWI times series to infer patterns of floodplain inundation and river-floodplain connectivity in two contrasting polders in the Lower Oder Valley National Park. Continuous wavelet transformation was used to investigate which timescale the hydrological variables present the pronounced variations. Wavelet coherency was employed to capture the factors contributing the hydrological connectivity. The upstream Polder A (14.4 km2) was extensively flooded for prolonged periods most winters and its strong seasonality was primarily driven by winter water levels in the river Oder (through 2 floodgates). Inundation of the downstream Polder 10 (17.7km2) was lower and had less marked seasonality, which reflected the impact of flood attenuation by storage in Polder A upstream, but also the greater connectivity (via 10 flood gates) to the Oder and a functional network of channels which facilitated rapid drainage. In Polder A, secondary periods of transient inundation could also occur in response to local intense summer rainfall, this was less evident in Polder 10. Groundwater recharge in and around Polder A is primarily induced by floodwater, whilst Polder 10 also reflects the influence of local rainfall-driven recharge. The hydrological connectivity regimes of the two polders showed marked inter-annual variation, largely dependent on flows from the upper Oder catchment. Understanding the hydrological connectivity in this system is important for sustaining and managing valuable wetland habitats within the National Park. Given projected climate change for this region and possible management alterations to the flow regime of the Oder, potential implications for these habitats needs urgent attention.
Dynamical Response of the Arabian Sea Oxygen Minimum Zone to the Extreme Indian Ocean Dipole Events
Authors: Zhang Zhiwei
Published: March 2024

The Indian Ocean dipole (IOD) has a significant impact on the global atmospheric circulation and contributes to determining important aspects of local and global environments. Although the IOD events can significantly cause SST anomalies and chlorophyll fluctuations in the western Indian Ocean, there is still very little known about the interannual variability of the Arabian Sea oxygen minimum zone (ASOMZ) under the influence of these remote forcing processes. In this study, a coupled physical-biogeochemical numerical model was used to investigate the dynamical response of the ASOMZ to extreme negative (2016) and positive (2019) IOD events. Our findings revealed that the suboxic area of the ASOMZ reduced (expanded) by about 27% (about 28%) after the negative (positive) IOD event. Compared to the 2019 pIOD event, approximately 2.5 times more oxygen-rich water was delivered into the Arabian Sea during the 2016 nIOD event, replenishing dissolved oxygen (DO) consumed by intensified upwelling-induced enhanced remineralization of particulate organic matter (POM), thereby increasing the DO concentration in the Gulf of Aden. Conversely, more POM from the upwelling regions in the western Arabian Sea was transported to the central Arabian Sea, leading to a subsequent decrease in DO concentration there. These findings contributed to our understanding of the ASOMZ's response to IOD events, which is essential for studying the Arabian Sea's marine ecosystem.
Abandoned quarry reclamation by selecting the appropriate plant species.
Authors: Xiroudakis George , Saratsis George , Gogali Kalliopi , Giannakaki Maria
Published: March 2024

Mining activity has been an essential human activity since ancient times, contributing to human society's economic and cultural development. Today, surface mining activity in Greece is significant both economically and socially. A large number of quarries for aggregates and ornamental stones throughout the country contributes to the economic development of local communities and is the main occupations of mineral resources engineers.However, it is an activity that significantly affects the natural environment, causing a range of impacts, reversible or irreversible, leading to the degradation of the area and visual alteration of the landscape. The environmental impact is considerable, and the concerns about protecting the landscape and ecosystems are growing. All thesecan be anticipated and dealt with by organizing and planning a landscape restoration study.This research focuses on the landscaping and restoration of an aggregate quarry at the 'Latzimas' site in the prefecture of Rethymnon, Crete. In this context, two restoration proposals are made, including:- the phytotechnical restoration of the quarry benches and pit floor using appropriate plant species,- and the reuse of the quarry through the creation of a:A) model vineyard,
B) botanical garden.
Usually, as the most suitable vegetation species are chosen the ones that thrive in the area instead of the ones that thrive in poor nutrient conditions, such as the environment of the abandoned quarries. Because of the above, the quarry engineer, who usually does not have the necessary knowledge of botany, will need to consult with experts (e.g. botanists and foresters) to ensure that the restoration plan is effective and not only aimed at meeting the obligations imposed by the legislation.
Integrating knowledge and establishing exchange on sea level rise to advance policies
Authors: Sielemann Dr. Katharina , Kirschmann Annette , Brunner Dr. Almut , Heidenreich Marie
Published: March 2024

Achieving a successful science-policy dialogue requires aligning scientific data with the needs of decision-makers, ensuring political relevance, scientific expertise, and timeliness. Essential to this process are face-to-face interactions, which are crucial to develop a mutual understanding of the needs, requirements, and perspectives of both sides. This approach ensures that the information provided to policymakers is not only accurate but also actionable. Therefore, establishing a common understanding of the topic/issue and identifying mutual needs is central to this dialogue. Further, incorporating multiple perspectives and diverse expertise is key to increasing the credibility and impact of scientific information, providing a comprehensive view of complex issues.In 2023, Helmholtz SynCom, together with scientists from the Helmholtz Centres AWI, GFZ, GEOMAR, and Hereon, has designed a parliamentary breakfast on the topic of sea level rise. This event aimed to inform political decision makers about the sources, impacts, and significance of sea level rise for Germany, with a further objective of fostering enduring relationships and promoting the dialogue between Helmholtz experts and federal politics. In summary, the parliamentary breakfast served as an effective instrument to initiate and strengthen the dialogue between science and politics. It also functioned as a platform to concisely present complex research topics, such as sea level rise, in a targeted manner from a holistic scientific perspective and to discuss the socio-political relevance and the current need for action with the responsible policymakers.This case exemplifies how targeted, engaging events like parliamentary breakfasts can effectively bridge the gap between science and policy, fostering productive dialogues crucial for informed decision-making.
Windstorm losses in Europe - What to gain from damage datasets
Authors: Moemken Julia , Messori Gabriele , Pinto Joaquim G.
Published: March 2024

Windstorms are among the most impacting natural hazards affecting Western and Central Europe. Information on the associated impacts and losses are essential for risk assessment and the development of adaptation and mitigation strategies. In this study, we compare reported and estimated windstorm losses from five datasets belonging to three categories: Indices combining meteorological and insurance aspects, natural hazard databases, and loss reports from insurance companies. We analyse the similarities and differences between the datasets in terms of reported events, the number of storms per dataset and the ranking of specific storm events for the period October 1999 to March 2022 across 21 European countries.A total of 94 individual windstorms were documented. Only 11 of them were reported in all five datasets, while the large majority (roughly 60%) was solely recorded in single datasets. Results show that the total number of storms is different in the various datasets, although for the meteorological indices such number is fixed a priori. Additionally, the datasets often disagree on the storm frequency per winter season. Moreover, the ranking of storms based on reported/estimated losses varies in the datasets. However, these differences are reduced when the ranking is calculated relative to storm events that are common in the various datasets. The results generally hold for losses aggregated at European and at country level.Overall, the datasets provide different views on windstorm impacts. Thus, to avoid misleading conclusions, we use no dataset as “ground truth” but treat all of them as equal. We suggest that these different views can be used to test which features are relevant for calibrating windstorm models in specific regions. Furthermore, it could enable users to assign an uncertainty range to windstorm losses. We conclude that a combination of different datasets is crucial to obtain a representative picture of windstorm associated impacts.
Pathways to temperature variability in South Asia
Authors: Shah Hardik , Monteiro Joy
Published: March 2024

For improving climate projections, there is a need to understand the physical processes governing the variability of dynamically driven variables, like near-surface temperature. Studies have shown that some features like surface drying and anticyclonic upper level conditions are associated with enhanced surface warming. However, the different ways in which surface, radiative and atmospheric variables compound to cause a heatwave, and the relative magnitudes of these variables and their relationship with heatwave intensity has not been well understood. Further, the large scale dynamics governing such conditions, and the effects of slowly varying climate features like ENSO and AO, are unresolved.Using the ERA5 reanalysis dataset, we are studying the drivers of variability of daily mean 2 meter temperature (T2m) anomaly over the northwest Indian heatwave hotspot region, in the entire premonsoon season (March to June). Our approach is to develop an interaction framework which identifies governing surface and weather regimes active during different months, and quantify how large-scale climate patterns modulate their frequency of occurrence. We are leveraging the decision tree classification framework to identify the dominant weather patterns explaining different quartiles of T2m anomaly, owing to its non-linear modeling capability. During March and April, the T2m anomalies are accompanied by a vertically coherent temperature anomaly field, and typically last only for a day or two. The decision tree classification algorithm suggests that anomalous surface warming during this period is preceded by increased shortwave radiation corresponding to subsidence across the tropospheric extent. The decay of such an anomaly is marked by decreased downward shortwave radiation fluxes and increased downward longwave radiation fluxes, indicating the role of ventilation and cloud formation. The direction of sensible flux anomaly also changes between the two phases, directed from the atmosphere to the surface in the warming phase, and from the surface of the atmosphere in the decay phase. During May and June, the warming anomalies last for more than three days, and the sensible heat flux anomalies are directed toward the surface. Although shortwave anomalies peak along with T2m anomalies, there is also an increased convergence of dry static energy in the lower troposphere, between 600–900 hPa, in the region. Geopotential anomalies on the 350 K isentropic surface are anti-correlated with potential vorticity anomaly, establishing the role of Rossby wave packets as the dynamical drivers of temperature variability in this region. Thus, we show how an interpretable machine learning algorithm like the decision tree could potentially identify proximal drivers and compounding factors of heatwaves, provide a way to rank them by their importance, and eventually lead to a multiscale framework by incorporating longer term signals such as ENSO. 
Dense network of wet bulb globe temperature observations to assess the effect of diverse micro-environments on heat stress
Authors: Hellebosch Ian , Top Sara , Caluwaerts Steven , De Ridder Koen , Theunissen Raf , Mensink Clemens
Published: March 2024

There is an urgent need for governments to know which measures effectively decrease heat stress and how to adapt urban environments to keep our cities livable in a climate with more, and more extreme, heatwave days. To answer this question, an observational campaign took place in the urban fringe of Ghent (Belgium), a maritime mid-latitude city, during the summer of 2023, including a heatwave in June. This campaign employed diverse in-situ weather stations (2 Campbell stations, 2 Hobo devices and a station from the Flemish MOCCA and VLINDER networks) complemented by 16 AT-HTS01 devices, specifically designed to measure heat stress. Combined, the stations are equipped with black globe thermometers, anemometers, humidity sensors, short-wave radiation pyranometers and actively and passively ventilated air temperature sensors. Based on these variables the wet bulb globe temperature (WBGT) is computed and from this, the influence of different suburban micro-environments on heat stress is derived. In particular, the effects of the surface type, neighboring buildings, trees and forest patches on WBGT are investigated. Some air temperature sensors are installed in actively ventilated shields to detect air temperature differences in different forest patches excluding any radiation-induced measurement errors. Additionally, drone infrared measurements were conducted to estimate the surface temperature of the different surface types during the day and the night. A forest patch decreases the maximum air temperature during the heatwave to up to 1.5°C. At night, the unpaved surface decreases the globe temperature to up to 1.5°C compared to paved surfaces. During daytime shadow effects of buildings and trees have the largest impact on decreasing the globe temperature (by 10°C) and consequently strongly lowers the actual WBGT (up to 4°C). Future research will focus on validating meter-scale numerical models with these observations.
Identification of microplastic present in the atmospheric aerosol of the Port of Veracruz
Authors: Vega Aguilar Nancy Viridiana , Reynoso Cruces Salvador , Ochoa Moya Carlos Abraham , Beristain Montiel Erick , Alvarez Ospina Harry
Published: March 2024

In recent years, the study of microplastics has garnered increased interest due to their impact on ecosystems and human health. However, most research has focused on characterizing this emerging contaminant in sedimentary, biological, and aqueous matrices, with very few studies dedicated to determining its presence in atmospheric aerosol. To address this knowledge gap, a campaign was conducted from May 23 to June 7, 2023, to collect microplastic samples in PM2.5 particulate matter using an active method with a Teflon filter at a flow rate of 16 L/min in the Port of Veracruz. Under the BA310Pol optical microscope at 5x and 10x magnification, each filter was analyzed to determine the presence and morphology of microplastics. The average concentration of microplastics was 0.041 MP m-3 ± 7.06, with 292 particles identified as fibers, film-like, fragments, films, and spheres. Among these, fibers and film-like particles were the most abundant. Chemical characterization was performed using FTIR, revealing PET as the more dominant plastic in the samples. On the other hand, toxic pollutants can adsorb to microplastic particles, so the presence of PAHs was also determined.The benzo[a]anthracene, chrysene, and benzo[a]pyrene are the most abundant. The findings highlight the necessity for further research into the presence of microplastics in the air, particularly in the breathable fraction, as it poses a potential threat to public health.
Determination of ocean structure on response of sea surface temperature and chlorophyll to typhoon in NW Pacific Ocean 
Authors: Wang Yuntao
Published: March 2024

Typhoons in the northwestern Pacific induce strong oceanic responses. Using 17 years of satellite observations, the impacts of typhoons on sea surface temperature (SST) and chlorophyll-a (Chl-a) are investigated. The SST time series shows that the SST begins to decrease 2 days before the typhoon’s arrival and continues to decrease until 2 days following the typhoon’s passage. The Chl-a has a weak peak 2 days prior to the typhoon’s arrival, rapidly increases after the typhoon arrives, reaches the strongest response on the third day of the typhoon, and gradually decreases to a value slightly higher than the pre-typhoon level. Prominent responses are associated with typhoons that have stronger intensity and slower translation speed. The pre-typhoon upper ocean structure plays a dominant role in determining oceanic responses. Surface cooling is generally stronger where the pre-typhoon mixed layer depth (MLD) is shallow. However, the change in Chl-a shows a contrasting response in that the response prominently increases only when the depth of typhoon-induced mixing exceeds the pre-typhoon MLD. This study poses a quantitative approach to assess the influence of typhoons on the upper ocean from a statistical perspective with consideration of the upper ocean structure.