bluuebunny/crossref_metadata_2025 huggingface dataset:
Firn aquifers in Antarctica: High-resolution mapping highlights predominance in the Antarctic Peninsula
Authors: Di Biase Valeria , Kuipers Munneke Peter , de Roda Husman Sophie , Veldhuijsen Sanne , van den Broeke Michiel , Wouters Bert , Noël Brice
Published: March 2024

Perennial firn aquifers in Greenland are crucial for meltwater storage, significantly influencing ice-sheet hydrology. In Antarctica, although firn aquifers have been identified in situ, a comprehensive continent-wide overview is currently lacking. Using an advanced methodology that integrates multiple datasets, our pioneering study presents a 2 x 2 km resolution assessment of firn aquifer distribution in Antarctica.The focal point of our analysis is the creation of a heat map of firn aquifer locations across Antarctica. In contrast to prior studies, reliant on traditional binary evaluations of aquifer presence or absence, our method addresses the inherent uncertainty associated with firn aquifer extent and overcoming challenges posed by the vast and remote Antarctic environment.We use a Monte Carlo method that exploits multiple datasets as input, spanning from 2017 to 2021. Data includes Sentinel-1, Advanced SCATterometer (ASCAT), and statistically downscaled output from the RACMO2.3p2 climate model. Each of these datasets highlights a particular property of firn aquifers.Our high-resolution heat map reveals a concentration of firn aquifers across the Antarctic Peninsula (AP). Elevated probabilities are observed along its northern, northwest, and western coastlines, as well as on the Wilkins, Müller, and part of George VI ice shelves. Beyond the AP, aquifer evidence is sparse, with only a few locations exhibiting slightly elevated probabilities, such as on the Abbot, Shackleton, and Holmes ice shelves.Validation of the methodology applied in Greenland using Operation IceBridge (OIB) data demonstrates a 91% correspondence with observed aquifers, firmly establishing the robustness of our approach.Leveraging the sustained accessibility of freely available C-band and scatterometer observations, complemented by modeling data, our approach allows for ongoing long-term monitoring of aquifer conditions, proving crucial to explore the response of the Antarctic ice sheet to climate change.
Characterization of land surface water flux under vegetation greening introduced by changes in climate and land-use
Authors: Bao Zhenxin , Wang Jie , Ruan Yuli
Published: March 2024

Detailed changes in land surface water fluxes under vegetation greening is unclear especially in different patterns of climate change and land-use change. A typical vegetation greening region located in Loess Plateau was selected as a studying area. Because of high spatial heterogeneous site conditions, similar spectral reflectance and shapes of different vegetation types, there is a low accuracy of land cover mapping in mixed regions of multiple vegetation types, thereby leading to a pronounced underestimate of land use change, such as grain for green project. Besides spectrum, topography, and some usually used features, a novel land cover mapping framework is constructed with evapotranspiration which vary dramatically in vegetation types. Generally, the classification accuracy of all kinds of land cover is above 90%, and improved by 5.4-15.3%, 0-15.7%, 3.0-20.4%, of cropland, forest and grassland, respectively. Then water fluxes including precipitation, evapotranspiration, soil moisture, and runoff were analyzed in nine different vegetation types, considering the three types of vegetation found in cropland, forest and grassland along with respective stable, loss, and gain states. The result indicated that the cropland returning and afforestation has successfully facilitated a positive regional water cycle. This finding is useful for supporting ecological restoration and future water resources management, and enhancing the carrying capacity and resilience of the region.
Lessons from a decade-long drought and non-recovery: hydrological processes understanding and modelling
Authors: Saft Margarita , Peel Murray , Peterson Timothy , Fowler Keirnan , Trotter Luca , Weligamage Hansini
Published: March 2024

Prolonged changes in climatic conditions can induce unexpected shifts in catchment hydrologic functioning due to the indirect impact of catchment adaptation on streamflow. In a multiyear drought, streamflow can be reduced significantly more than expected from the typical response to the same annual precipitation. For example, the same annual rainfall in the first and the tenth years of a dry period is likely to result in significantly lower streamflow during the tenth year than in the first year. Such hydrological shifts were first detected in Australia during the Millennium Drought (1997 – 2009). Since then, similar shifts were also reported in studies from other continents. Subsequently, it was also discovered that catchments, once they shift their hydrologic behaviour, may not necessarily recover back to the pre-drought behaviour even after record-breaking floods and years of annual rainfall similar to the pre-drought conditions. Observed shifts not only challenge some common assumptions of long-term hydrologic functioning but also present an interesting practical problem as hydrological models tend to reproduce historic behaviour and systematically overestimate the streamflow when the hydrologic shifts occur. Here we present the results from a large collaborative project in Australia devoted to two questions (1) which hydrological processes are responsible for the observed shifts and (2) how to improve our hydrological models to provide robust predictions under non-stationary climate? We hope that the lessons from the Millennium drought and post-drought period will be helpful in the other parts of the world where similar hydrological shifts were or will be observed.
Advancing Hydrological Modeling for Detailed Water Budget Assessment in Indian River Basins: A High-Resolution Approach
Authors: Kushwaha Anuj Prakash , Mishra Vimal
Published: March 2024

In recent years, there has been an increasing demand for enhanced hydrological modeling, monitoring and high-resolution data. The hydrological community has grappled with persistent challenges, notably the limited availability of observations at the required spatial and temporal resolution. The availability of high-resolution satellite-based, reanalysis, and ground-based observations has significantly improved compared to previous decades, unlocking new opportunities for detailed and precise analyses across various domains. Despite the profound importance of the high-resolution data, it has been lacking in the Indian region. This study addresses the gap by developing high-resolution (0.05°) data for precipitation and maximum and minimum temperatures for the South Asian region. Next, we employ hydrologic modelling frameworks (VIC) to simulate the hydrologic variables (Evapotranspiration, baseflow, surface flow, soil moisture, etc.). Subsequently, the study will extend to estimating water budgets, identifying trends, and analyzing changes at the sub-basin level. Additionally, a focus on climate extremes will provide insights into the taluka level in South Asia. The outcomes of this research are poised to offer valuable contributions to policymakers, governmental bodies, and researchers, facilitating improved water resource management. 
Archive prototype for Space Weather phenomena chains from the Sun to the Earth: CAESAR for ASPIS
Authors: Molinaro Marco ,   CAESAR Team
Published: March 2024

CAESAR (Comprehensive Space Weather Studies for the ASPIS Prototype Realisation) is a project funded by ASI (Italian Space Agency) and INAF (Italian National Institute for Astrophysics) for the development of the prototype of ASPIS (ASI SPace weather InfraStructure). We report here design considerations, challenges and final status of the creation of a database for the ASPIS prototype, which will allow for the study of the chain of phenomena from the Sun to Earth and planetary environments. The database is aimed at handling the heterogeneity of metadata and data while storing and managing the interconnections of various Space Weather events. On top of the database, interfaces for users, including a graphical web interface and an advanced Python module (ASPIS.py), have been developed to facilitate data discovery, access, and analysis. The high-level metadata, to inform the discovery phase in the database, have been collected using an internally developed tool, ProSpecT (Product Specification Template). This tool utilises JSON Schema and JSONForms to create a web interface to guide the data providers in describing their "Products" and generate a JSON object with the necessary metadata. The metadata structure starts from the IVOA VOResource standard, tailored to suit the CAESAR project's requirements. At present, approximately 100 product descriptions in JSON format have been collected and used to create wiki-like documentation pages besides helping in examining formats and metadata details for the implementation of the database prototype. The graphical web interface helps the users discover, filter, and access the database content, while ASPIS.py also provides more advanced analysis tooling. Moreover, ASPIS.py sits on top of commonly used Python packages like SunPy, scikit-learn, matplotlib to help integrate research analysis with other tools and research domains. The database has been built keeping in mind adherence to FAIR principles and with the idea to make it easily interoperable with other research data infrastructures in the Space Weather or sibling research domains.
Improvement of ammonia emission inventory using life cycle assessment based on livestock manure flow: A case study of manure management sector of Korea
Authors: Joo HungSoo , Lee HyeMin , Kim Kyoungchan , Han JinSeok , Baek Jeongdeok
Published: March 2024

Ammonia is one of precursor gases to form particulate matter (PM) which is reacted with nitrogen oxides and sulfur oxides in the atmosphere. Based on Clean Air Policy Support System (CAPSS) of Korea, annual ammonia emission is 261,207 tons (year of 2020) and the agricultural sources (manure management sector) emits the highest portion of ammonia. In this study, we aim to recalculate ammonia emissions of livestock industry using the UK's estimation method which is used the life cycle assessment of livestock manure mass flow. four major animal kinds were selected, i.e., cattle (beef cattle and dairy cow), pigs and chickens and three major processes as the manure flow were included such as housing, manure treatment (composting and liquefied fertilization) and land application. Total ammonia emissions were estimated to be approximately 33% higher than the current official ammonia emissions by CAPSS. Ammonia emissions from pigs and poultry were high in four major animal kinds. Relative ammonia emissions from beef cattle and poultry was much higher than those by CAPSS. Highest ammonia emissions were emitted from land application on manure flow. The emission factors of dairy cow and poultry was much higher than those by CAPSS, while the emission factor of pigs was slightly lower than that those by CAPSS. The methodology for the estimation of ammonia emissions used in this study can be a new approach for the estimation of the manure management sector in CAPSS. As a further study, the development of Korean emission factors for each manure flow can be suggested. Acknowledgments:This research was supported by Particulate Matter Management Specialized Graduate Program through the Korea Environmental Industry & Technology Institute (KEITI) funded by the Ministry of Environment (MOE)
HBV Performance under complex and poorly gauged context
Authors: El Garnaoui Mohamed , Boudhar Abdelghani , Karaoui Ismail , Chehbouni Abdelghani
Published: March 2024

In North African countries where water scarcity and limited data prevail, employing predictive hydrological modeling is crucial to gain accurate insights into current and future water reserves. Hence, these models parameters exhibit instability in this context due to the climate variability observed through basins. Therefore, our efforts focus on using a combination of measured data, remote sensing information, and reanalysis data for calibration and validation, to check the improvement in the result accuracy. Through this study, we simultaneously investigate the spatiotemporal stability of the HBV model in several sub-catchments of Oum Er-Rbia Basin, by improving the performance of a bucket-type conceptual model. We created a Nested Cross-Validation (NCV) framework to assess spatiotemporal stability. The framework uses optimal parameters from a donor catchment of the Hydrologiska Byråns Vattenbalansavdelning (HBV) model as inputs for target catchment parameter ranges. In particular, we evaluated HBV's capacity for prediction over time and space, as well as its impact on model parametrization throughout the regionalization process in the setting of sparse data catchments. As results, the HBV model is spatially transferable from one basin to another, with NSE ranging from  0.5 to 0.8 and KGE values between 0.1 to 0.9, meaning a moderate to high performance. The HBV optimum parameter sets exhibit unpredictable behavior over space. On the contrary, their inter-annual behavior is nearly identical. It also detected a decrease in the model's predictive skills over time, which can be explained by the research area's tendency to dry out year after year. Furthermore, employing KGE for calibration rather than NSE improves model predictive performance significantly. The model  calibration process with the KGE outperformed those with the NSE metric, especially when simulating high flows. Furthermore, the findings demonstrate a significant relationship between high model performance and high values of several optimal parameter sets throughout the calibration and validation periods.Keywords: HBV model, poorly gauged basin, arid and semi-arid region, KGE, NSE.
Using Deep Learning for Convection Parameterization
Authors: Zhang Guang , Han Yilun , Wang Yong
Published: March 2024

Data-driven approaches using machine learning to parameterizing model physical processes in Earth System Models have been actively explored in recent years. Deep-learning-based convection parameterization is one such example. While significant progress has been made in emulating convection using neural networks (NN), serious roadblocks remain, including generalization of the NN-based scheme trained on model data from current climate to future climate and integration instability when it is implemented into the model for long-term integrations. This study uses a deep residual convolutional network to emulate convection simulated by a superparameterized global climate model (GCM). The NN uses the current environmental state variables and advection tendencies, as well as the history of convection to predict the GCM grid-scale temperature and moisture tendencies, cloud liquid and ice water contents from moist physics processes. Independent offline tests show that the NN-based scheme has extremely high prediction accuracy for all output variables considered. In addition, the scheme trained on data in the current climate generalizes well to a warmer climate with +4K sea surface temperature in an offline test, with high prediction accuracy as well. Further tests on different aspects of the NN architecture are performed to understand what factors are responsible for its generalization ability to a warmer climate. We are also able to perform multi-year integrations, without encountering any integration instability, when the scheme is implemented into the NCAR CAM5. The details will be presented at the meeting.
Role of spatial covariance in regulating interannual variability of Indian Summer Monsoon rainfall
Authors: Chandel Vikram , Ghosh Subimal
Published: March 2024

The interannual variability (IAV) of All India summer rainfall (AIMR) is low, with a Coefficient of variation (COV) around 9% of the long-term mean. Though regulated by global and regional sea surface temperatures, we explore the cause of low COV of AIMR due to the spatial distribution of rainfall. We find that the variability of AIMR is affected by the spatial covariance between the subregions with different rainfall characteristics, such as the arid western and wet northeast regions. By removing regions, one at a time, from the Indian region, we find that COV increases after removing the Northeast (NE) region due to negative covariance between NE and other sub-regions of India, especially Central India (CI). Further research is ongoing to explore the moisture distribution over the subregions and understand the negative covariance using a moisture tracking algorithm. We plan to investigate the contributions to rainfall distribution from oceanic and terrestrial sources. This study may reveal how the spatial distribution of rainfall influences the IAV of AIMR, emphasizing the significance of terrestrial and oceanic moisture contributions.
Growing an ocean island: high-precision seismicity reveals a multi-faceted magma intrusion during the 2022 São Jorge, Azores seismic crisis
Authors: Hicks Stephen P. , J. Gonzalez Pablo , Fernandes Rui , Ferreira Ana , Ramalho Ricardo , Mitchell Neil , Lomax Anthony , Carrilho Fernando , Custódio Susana , Dias Nuno Afonso , Fontiela João , Mendes Virgilio , Garcia Arturo M. , Marignier Augustin , Marques Rui , Miranda Miguel , Melo Octavio , Pimentel Adriano , Silveira Graça , Tsekhmistrenko Maria ,   and the rest of the Sao Jorge investigation group
Published: March 2024

The central islands of the Azores Archipelago in the North Atlantic straddle a diffuse zone of dextral transtension between the African and Eurasian plates, providing an ideal setting for studying the interplay between tectonics and magmatism. São Jorge is a narrow island dominated by a westward progression of past basaltic fissure eruptions, where fault zones act as volcanic rifts. After two inland eruptions with significant socioeconomic impact in 1580 and 1808, the most recent probable eruption occurred offshore in 1964, after two years of seismic activity. In March 2022, a seismic crisis began on São Jorge (magnitudes up to ML 3.8). Our analyses of InSAR and GNSS data are consistent with a dike intrusion that stalled at 2 km depth below sea level. Here, we use seismicity to probe the space-time evolution of the intrusion. The unique geography and near-coastal position of seismicity yield inherently uncertain locations. To address this, we supplemented on-land stations with 6 ocean-bottom seismometers (OBSs) around the island later in the crisis. We use NLL-SSST-coherence, a location method ideal for changing station density, to exploit later OBS data to form robust source-specific station terms that allow precise relocation of the earlier part of the seismic sequence when coverage was sparser. In a final step, we combine waveform coherence and location uncertainty stacks to enhance hypocenter location precision to
A cross-scale methodological framework for the quantification of the impact of urban features on intra-city microclimate
Authors: Ding Xiaotian , Zhao Yongling , Strebel Dominik , Fan Yifan , Ge Jian , Carmeliet Jan
Published: March 2024

Evaluation of the outdoor thermal comfort and comprehension of the impact of urban morphology are essential for assessing heat-related risks and implementing urban planning strategies that enhance the resilience of urban populations to extreme heat events. However, the challenge lies in achieving city-wide thermal comfort mapping at high spatial and temporal resolutions, which requires consideration of the complex urban morphology (urban geometry and land cover) at a microscale, as well as the background meteorological factors at larger scale. Here, we introduce an effective framework for city-scale thermal comfort mapping at high spatial-temporal resolution that integrates WRF-UCM and SOLWEIG model, aiming to achieve fine-grained thermal comfort mapping at the city scale and to explore the impact of urban morphology on these thermal conditions.In the proposed framework, we employ the WRF-UCM model (The Weather Research and Forecasting model coupled with the urban canopy model) to establish the background meteorological condition at local-scale (500m resolution). Additionally, we utilize the SOLWEIG (Solar and Longwave Environmental Irradiance Geometry) model for the simulation of mean radiant temperature at a finer micro-scale (10m resolution), a critical determinant of thermal comfort. These simulations are performed using detailed 3D urban morphological data and land cover information. Subsequently, the Universal Thermal Climate Index (UTCI) is calculated on hourly basis, integrating the aforementioned factors.A case study conducted for a Chinese city with a population of 15 million demonstrates a significant correction between the rise in the UTCI during daytime and an increase in impervious surface area, evidenced by a maximum correlation coefficient of 0.80. Furthermore, our findings emphasize the significance of tree canopy coverage in mitigating heat, demonstrating that an implementation of 40% tree cover could diminish daytime UTCI by approximately 1.5 to 2.0 ºC. This methodological framework is not only instrumental in assessing heat-related risks and human thermal discomfort within intricate urban environments but also offers pivotal insights for the adoption of climate-resilient urban planning strategies.
The Study of Quantum Phenomena with the Cold Atom Lab in Microgravity 
Authors: Williams Jason , Oudrhiri Kamal , Aveline David , Botsi Sofia , Elliott Ethan , Kellogg James , Kohel James , Lay Norman , Sbroscia Matteo , Schneider Christian , Thompson Robert
Published: March 2024

The Cold Atom Lab (CAL) launched to the International Space Station (ISS) in May 2018 and has been entirely remotely operated from NASA's Jet Propulsion Laboratory since then as the world's first multi-user facility for studying ultra-cold atoms in space. CAL uses lasers and magnetic traps to cool atoms down to less than a degree above absolute zero. When clouds of atoms reach these ultracold temperatures, they form a fifth state of matter called a Bose-Einstein Condensate (BEC). Distinct from gasses, liquids, solids, and plasmas, a BEC makes the quantum properties of atoms macroscopic, so scientists can more easily observe and interact with them in the essentially limitless free-fall of ISS. An on-orbit upgrade to CAL in 2021 enabled the study of atom interferometry (AI) in space, which uses the interference of atomic matter waves as exquisitely precise sensors for fundamental forces, including gravity, accelerations, and rotations. Relevant to Earth and planetary sciences, these quantum sensors are expected to serve as precision gravity sensors for geodesy, seismology, and subsurface mapping in the near future. We will discuss our efforts to provide pioneering, microgravity-enabled quantum gas research capabilities with CAL, to demonstrate AI for the first time in Earth's orbit, to realize simultaneous, dual-species atom interferometry in space, and to mature this technology for future mission opportunities. © 2024 California Institute of Technology. Government sponsorship acknowledged.
Does the tropical atmosphere support Doppler shifted MRG waves?
Authors: Keshri Shreya , Ettammal Suhas
Published: March 2024

MRG wave belongs to one of the major synoptic scale modes of tropical atmospheric variability and they exhibit the properties of both slowly evolving Rossby and quickly evolving gravity type wave disturbances. Since the MRG waves bridges the gap between the low-frequency and high frequency modes of variability, it is crucial to understand the underlying dynamics of the MRG waves to improve the tropical weather and extended range forecasts. Many previous studies reported the observation of Doppler shifting of MRG waves in the western Hemisphere (e.g. Yang et al. 2003, 2007, Yang and Hoskins 2016 etc). Nevertheless, a comprehensive study of eastward propagating Doppler shifted MRG (E-MRG) waves and their frequency of occurrence relative to the westward propagating MRG waves is missing. In this study, we investigate the E-MRG wave events at 200 hPa pressure level using the wave fitting and Empirical Mode Decomposition (EMD) based wave event identification methodology. We have found 743 E-MRG wave events for the period 1979-2022 and a large fraction of them occur in the westerly duct during boreal winter seasons. It is noteworthy that E-MRG wave events account 33% of the total MRG wave events in the western Hemisphere during boreal winter seasons. As expected from the linear wave theory, 75% of the E-MRG wave events occur when the background winds are westerly. On the contrary, a notable fraction of the E-MRG events occur when the background winds are easterly. Detailed analysis reveals that westerly phase of the large-scale Kelvin waves setup the conducive environment for MRG wave events to be Doppler shifted and explain more than 75% of the E-MRG wave events that occur when the background winds are easterly. In addition to that the observation of strong link between the intrusion of eastward propagating extratropical disturbances and the E-MRG wave events support the extratropical-tropical interaction theory of Hoskins and Yang, 2016. The study underscores the importance of multiscale interactions and its realistic representation in the climate and numerical weather prediction models.
Volcanic ash likely triggers N2 fixation in the Andaman Sea 
Authors: Saxena Himanshu , Sahoo Deepika , Rathi Ajayeta , Nazirahmed Sipai , Kumar Sanjeev , Singh Arvind
Published: March 2024

Marine N2 fixation fuels the growth of primary producers, drives marine carbon export fluxes, and in turn, influence the Earth’s climate. While the Bay of Bengal is at least explored, the Andaman Sea, which is adjacent to the only active volcano of the south Asia and is separated from the Bay of Bengal by the Andaman and the Nicobar Islands to its west, has never been explored for its viability to N2 fixation. The warm and oligotrophic surface waters and suboxic subsurface waters of these two basins may provide suitable stimulus for N2 fixation. We investigated N2 fixation in the euphotic and the oxygen minimum zones of the Bay of Bengal and the Andaman Sea during the autumn inter-monsoon. We found that N2 fixation is about an order of magnitude higher in the surface waters of the Andaman Sea than the Bay of Bengal, attributable to the relatively high iron input associated with volcanic ash deposition in the Andaman Sea. We underscored that N2 fixation at the immediate sea surface (sampled manually through a bucket) is largely four times higher than the subsurface waters at 10 m depth (sampled through CTD) in the northeastern Indian Ocean. Our findings imply that the traditional CTD rosette sampling is unable to capture the surface N2 fixation activity, and therefore, previously reported N2 fixation rates in the global ocean are likely to be massively underestimated.
Locating the shift in the plant fluorescence role under stress conditions
Authors: Cochavi Amnon , Sadeh Yaara , Shemer Or Emma
Published: March 2024

Sun-induced fluorescence (SIF), which serves as a proxy of plant and ecosystem net carbon assimilation (or gross primary production, GPP, at the ecosystem level), has been observed to exhibit sustainability under optimal conditions. The recent evidence demonstrated a break of this relation under stress conditions, and a change in the fluorescence role for excessive energy dissipation.In this study, our aim was to identify the physiological alterations responsible for the transition. To achieve this, we utilize both natural and induced stress conditions to investigate the changing role of fluorescence. Initially, we examine the impact of sustained drought on the correlation between plant leaf-level gas exchange and Pulse Amplitude Modulation (PAM) parameters, in conjunction with plant Sun-Induced Fluorescence (SIF) and other spectral indices. In the subsequent phase, we use chemical inhibitors to assess the reaction of both susceptible and tolerant plants.The findings indicated that Sun-Induced Fluorescence (SIF) primarily interacts with the Non-Photochemical Quenching (NPQ) pathway. During the initial phases of rehydration, the SIF signal decreases correspondingly with the decline in photosynthetic activity. Subsequently, as NPQ levels reach saturation, the intensity of the SIF signal begins to rise. The use of photosystem inhibitors reinforces our observations from the drought experiment. The sensitive accession displays a rapid surge in the fluorescence signal, coinciding with a complete cessation of carbon assimilation. Conversely, in the tolerant accession, a simultaneous decrease in the fluorescence signal occurs alongside a partial decline in the rate of carbon assimilation.The results underscore the dual roles of plant fluorescence within the plant. Distinguishing between these two phases can assist in monitoring both plant and ecosystem responses under stress conditions.
Calcification Strategies in Sorites orbiculus: Insights from Ultrafine Structure Observations and pH Variations
Authors: Toyofuku Takashi , Nagai Yukiko , Tsubaki Remi , Fujita Kazuhiko
Published: March 2024

Biomineralization processes are remarkably varied across the biosphere, yet the foraminifera stands out for their intricate construction of calcium carbonate shells—a phenomenon critical for interpreting paleoceanographic applications. In our research, we delve into the latest observations on the calcification strategy employed by the porcelain-shelled foraminifera Sorites orbiculus (Forsskål in Niebuhr, 1775), offering a reevaluation of the prevailing models of chamber formation. Utilizing focused ion beam scanning electron microscopy (FIB-SEM), we meticulously documented the ultrastructural development of the shell in calcification. Our findings may challenge the traditional vesicle-mediated crystal formation hypothesis, revealing a unique and complex cotton candy-like structure at the calcification site instead.
Simultaneously, pH imaging conducted during chamber formation has disclosed a fascinating pattern of pH elevation that transcends the newly formed chambers, extending to the final stages of calcification. This suggests a more intricate and systemic approach to biomineralization than previously understood. The localized increases in pH not only coincide with the morphological intricacies of the shell but also suggest a remarkable environmental plasticity inherent to S. orbiculus. Our nuanced comprehension of calcification, grounded in precise pH measurements and detailed microstructural observations, illuminates new facets of this species' biomineralization strategy. The insights gleaned here hold profound implications for redefining elemental partitioning and isotopic fractionation in foraminiferal shells and may herald a paradigm shift in our understanding of biomineralization within porcelain foraminifera.
 
Machine learning-based downscaling of coarse resolution temperature and its application for potential frost identification over complex terrain.
Authors: Bhakare Sudheer , Dal Gesso Sara , Venturini Marco , Zardi Dino
Published: March 2024

The precise representation of spatial temperature is important for practical applications like agriculture where they require local information at very high resolution for managing agricultural activities. In recent times, statistical downscaling methods, specifically those utilizing machine learning methods are gaining importance due to their computational of time efficiency over dynamic downscaling.This study focuses on enhancing the downscaling of spatial temperature over complex terrain using machine learning algorithms, particularly Random Forest (RF), Artificial Neural Networks (ANN), and Convolutional Neural Networks (CNN). The primary aim of this study is to identify the most promising machine learning model for downscaling gridded temperature at 2 meters from 9 km to 1 km over Non and Adige valleys. Additionally, we aim to apply these models for potential frost identification for the months of March, April, and May. We used static predictors such as Shutter Radar Topography Mission (SRTM) elevation which plays an important role in complex terrains to improve the performance of models. In addition to that, dynamic predictors such as zonal and meridional winds (U, V), windspeed, surface pressure (SP), etc. are used as auxiliary inputs. The study’s methodology includes training and evaluating the performance of three machine learning models using statistical metrics such as Root Mean Square Error (RMSE), Mean Absolute Error (MAE), R square (R2), and Mean Bias Error (MBE). Furthermore, we used other metrics such as recall, precision, and F1 score for assessing model performance for frost identification.Our results show CNN models outperform other models across all the seasons with the best performance in summer (RMSE=1, MAE= 0.78, R2=0.94) and the least in winter (RMSE=1.3, MAE=1, R2=0.87).  All These models exhibit a consistent pattern of having good performance in summer and least in winter. The superiority of the CNN model can be attributed to its ability to capture spatial patterns in temperature data which makes it more reliable for complex terrains. Additionally, for frost identification, CNN models show better performance with the highest F1 score across March, April, and May.
OpenWorkFlow - Development of an open-source synthesis-platform for safety investigations in the site selection process
Authors: Lehmann Christoph , Nagel Thomas , Kolditz Olaf
Published: March 2024

The identification of appropriate locations for secure nuclear waste disposal, a crucial aspect of Germany's nuclear phase-out strategy, remains a significant scientific, technical, and political challenge worldwide. The selection and safety assessment of sites demand extensive employment of numerical methods. The OpenWorkFlow project, initiated by Bundesgesellschaft für Endlagerung (BGE), is developing a new, open synthesis platform to virtualise repository systems. The simulation platform will evaluate far-field and near-field processes, aiding the site selection process first and geotechnical design of repository systems later on. Automated simulation and analysis pipelines developed in this project ensure the verifiability and reproducibility of all simulation results and the modularity of workflows brings flexibility, continuity and maintainability.This project defines high scientific benchmarks and standards for numerical models and software development for the repository search in Germany. OpenWorkFlow as an efficient and holistic platform for numerical modelling will contribute to a science-based, transparent, and precise execution of the necessary safety assessments. This project includes all theoretical, numerical and computational methods and tools, including a virtual reality framework. OpenWorkFlow will be continuously developed by the core project team, but will also actively involve the community through its open concept (e.g. through the interactive benchmarking platform). This will create a win-win situation in the long run.This talk is based on the paper Christoph Lehmann, Lars Bilke, Jörg Buchwald, Nico Graebling, Norbert Grunwald, Julian Heinze, Tobias Meisel, Renchao Lu, Dmitri Naumov, Karsten Rink, Ozan Özgür Sen, Philipp Selzer, Haibing Shao, Wenqing Wang, Florian Zill, Thomas Nagel, and Olaf Kolditz. Openworkflow - development of an open-source synthesis-platform for safety investigations in the site selection process. Grundwasser, 2024. in print.
Magnetic Fabric of Freshly Consolidated Lacustrine Mudstones Constrains the “Present-Day” Strain Field
Authors: Xie Hao , Liu Caicai
Published: March 2024

The anisotropy of magnetic susceptibility (AMS) has great potential in deciphering weakly deformed fabrics that may be related to tectonic stress. Previous studies have suggested that magnetic lineation is a good indicator of paleostrain direction. It is unclear whether the magnetic fabric can also be used to indicate the present-day strain field. To verify this idea, we measured the AMS of freshly consolidated lacustrine fine-grained and horizontal-bedding sediments at 11 locations in the Qaidam and Chaka-Gonghe basins of the northeastern Tibetan Plateau and compared it with the present-day strain field deduced from the Global Position System (GPS) velocity field. The AMS of these sediments appears a weakly deformed fabric with clear foliation and lineation. The optical and scanning electron microscope (SEM) images of the thin sections show that the elongated particles display an orientation parallel or subparallel to the magnetic lineation direction, confirming the effectiveness of magnetic lineation. The magnetic lineations of both room-temperature and low-temperature AMS are roughly perpendicular to the GPS-derived tectonic shortening direction within the error range, suggesting that the AMS of freshly consolidated muds is an effective indicator of the present-day strain field, even if the sediments appear undeformed at the outcrop scale.
Hydroxyl Radicals and Oxidation Capacity in the Tropical Troposphere: Measurements from CAFE Field Campaigns using HORUS
Authors: Holzbeck Philip , Rohloff Roland , Sreekumar Sreedev , Monteiro Carolina , Tsokankunku Anywhere , Marno Daniel , Martinez Monica , Nussbaumer Clara , Dienhart Dirk , Tripathi Nidhi , Wang Nijing , Edtbauer Achim , Bohn Birger , Obersteiner Florian , Williams Jonathan , Fischer Horst , Curtius Joachim , Pöhlker Mira , Lelieveld Jos , Harder Hartwig
Published: March 2024

In the tropics, intense solar radiation drives photochemistry and strong convection, transporting air from the boundary layer to the upper troposphere. Conditions in the tropics are characterized by high humidity and UV intensity enhancing hydroxyl (OH) radical production. In addition, OH radicals and ozone (O3) are formed through reactions of HOx (OH + HO2) with nitrogen oxides (NOx), the latter being produced by lightning in abundant convective systems. The convection also transports volatile organic compounds (VOCs), notably from emissions by the tropical rainforest. The VOCs are oxidized by radicals and O3, resulting in secondary species contributing to new particle formation. To understand and characterize the atmospheric chemistry in these conditions, the Chemistry of the Atmosphere Field Experiment (CAFE) Brazil was conducted from December 2022 to January 2023 with the High Altitude and Long Range Research Aircraft (HALO) in the Amazon region.In this study, we present preliminary results measured with the Hydroxyl Radical measurement Unit based on fluorescence Spectroscopy (HORUS), focusing on vertical HOx profiles measured during different times of the day over both the continent and the ocean, including the outflow of both electrified and non-electrified convective systems. In contrast to the conditions over the continents where lightning-generated NOx aids in the efficient recycling of radicals, over the ocean, the limited availability of NO hinders recycling and results in radical termination. The conditions over the continent are compared to those measured over the Atlantic Ocean during the CAFE Africa expedition in summer 2018 based in the Cape-Verde islands. This unique dataset provides valuable insights into the atmospheric chemistry and oxidation capacity in these tropical regions.
Depositional environments in the fjord head delta of deglaciated Dicksonfjorden, Svalbard: The impact of global warming after the post-little ice age
Authors: Jo Joohee , Kim Dohyeong , Sohn Seungyeon , Bang Seolhui , Jensen Maria Ansine , Nam Seung-il , Choi Kyungsik
Published: March 2024

Global warming after the Little Ice Age (LIA) has triggered rapid glacier retreat in an arctic coastal region, instigating substantial environmental changes in the fluvial-marine transition zone (FMTZ). A comprehensive understanding of the sedimentary environments affected by glaciofluvial, tidal, and wave processes is imperative for predicting the ongoing impacts of global warming. Despite logistical challenges and limited accessibility, we investigate the influence of glacier melting on the evolution of depositional environments in the Arctic FMTZ, focusing on the deglaciated Dicksonfjorden in Svalbard. Our study involves the collection of undisturbed cores from glaciofluvial rivers, tidal channels, and spits to elucidate the spatial distribution of sedimentary facies. Hydrodynamic observations in tidal channels enable to comprehend sediment transport dynamics. The glaciofluvial river which is nourished by high-turbid snowmelt waters forms braided channels that intricately dissect extensive tidal flats in the downfjord. Sedimentary facies reflect an increasing tidal influence, transitioning from downstream-directed climbing-rippled sands to interlaminated sands and muds towards the sea. Tidal point bars exhibit inclined heterolithic stratification, comprising bidirectional rippled silts and interlaminated silts. Gravelly beds on the spits incline towards the shore, primarily attributed to wave-induced cliff erosion. The microtidal regime, characterized by ebb tidal asymmetry, experiences peaks in suspended sediment concentration during ebb tides. Estimated sedimentation rates calculated from 210-Pb activities averaged 0.14 cm/year from the 1920s to 2020. Notably, the rate has increased from 0.07 cm/year (1980s-2000) to 0.23 cm/year (2000-2020). This study underscores the profound impact of accelerated climate warming on increased meltwater and sediment discharges post-LIA, driving active delta progradation and instigating morphological changes in deglaciated arctic coastal environments.
Clouds as the Primary Driver of Recent Prolonged Summer Heat Waves in South Korea
Authors: Cho Minjeong , Kim Ha-Rim , Choi Yong-Sang
Published: March 2024

Recent prolonged heat waves in South Korea have raised questions about the key factors influencing their duration. This study investigates the potential physical drivers affecting the duration of Korean summer heat waves over 50 years (1973–2022), categorizing two types of events: short-term (5–7 days) and long-term (≥16 days) events. Using JRA-55 reanalysis data, we examine the distinct characteristics of both event types in relation to components contributing to the surface energy budget. Additional attention is given to the role of soil moisture and clouds in interacting with these components. The primary cause of both heat wave events is an increase in net shortwave radiation flux, attributed to anticyclonic circulation over South Korea, resulting in decreased clouds. Nonetheless, notable differences emerge: the short-term event exhibits a rapid recovery in all-altitude clouds, while the long-term event displays a slower recovery in low-level clouds. Continuously fewer low-level clouds allow much more incoming solar radiation, mainly contributing to the prolonged heat waves. This is linked to a dry atmosphere and weak atmospheric instability, which inhibits the development of lower-level clouds. Moreover, long-term events also exhibit a sudden increase in clouds at 100–200 hPa, intensifying the trapping effect on outgoing longwave radiation in the atmosphere, and subsequently leading to surface warming. This study enhances a comprehensive understanding of the mechanisms behind prolonged summer heat waves in South Korea, providing valuable insights into the complex interplay of atmospheric components.
A sand tank experimental study of distribution, migration and transformation mechanism of iron and phosphorus species under redox fluctuation in a simulated riparian zone
Authors: Guo Ziwei , Wen Zhang , Bu Xiaochuang , Liu Hui , Yuan Songhu
Published: March 2024

The coupling transformation of iron and phosphorus in the riparian zone is of great significance on the biogeochemical cycle of iron and pollutants in surface water-groundwater interaction system. However, the spatial and temporal distribution, biochemical transformation and its pollution interception in the interaction zone is poorly understood. In this study, we used the sand tank experiment to investigate the migration and the transformation of iron and phosphorus under the redox fluctuation forced by the river stage in the riparian zone. Results show that there is a good correlation between the changes of Fe/Al coupled P and amorphous total Fe. Additionally, more attention should be paid to the effect of organic carbon rather than dissolved oxygen on the redox condition in the underground environment. It was also found that aqueous phosphorus usually accumulates in the transition area of the riparian zone regardless of the recharge or discharge relationship between river and groundwater. This study thus revealed the distribution, migration and transformation mechanism of iron and phosphorus in the typical fine sandy riparian zone, providing theoretical support for tracing and controlling the source of phosphorus pollution in riparian aquifer.
Connecting North American and European Weather Regimes
Authors: Messori Gabriele , Dorrington Joshua
Published: March 2024

Weather regimes are recurrent and quasi-stationary atmospheric circulation patterns, typically linking to surface weather and extremes. Despite their widespread use, little is known on whether or how regimes defined in different regions relate to each other and reflect long-distance teleconnection patterns. Here, we shed light on this knowledge gap, focussing on North American and Euro-Atlantic regimes. The selection of these two regions is motivated by recent evidence pointing to a systematic connection between winter weather in North America and Europe. We find that specific pairs of North American and Euro-Atlantic regimes show a close statistical correspondence and that their joint analysis can provide medium-range statistical predictability for anomalies in their occurrence frequencies. Conditioning on North American weather regimes also results in anomalies in both the large-scale circulation during specific Euro-Atlantic regimes, and the associated European surface weather. We conclude that there is a benefit in conducting joint analyses of North American and European weather regimes, as opposed to considering the two in isolation.
The fate of terrestrial carbon in the Arctic Ocean supplied by increasing coastal erosion
Authors: Mathis Moritz , Nielsen David , Hagemann Stefan , Ilyina Tatiana , Schrum Corinna
Published: March 2024

Arctic permafrost thaw and sea ice retreat lead to enhanced coastal erosion and a contemporary increase in the transport of terrestrial carbon to the Arctic Ocean. However, the influence of this carbon supply on the marine carbon cycle and the CO2 uptake of the broad Arctic shelves is poorly understood. We use the global ocean-biogeochemistry model ICON-Coast with a dedicated representation of coastal carbon dynamics to investigate the impacts of erosive coastal carbon input during the 20th century and quantify its partitioning into burial, transport and air-sea gas exchange in the Arctic Ocean. Anthropogenic climate change increased the carbon supply from coastal erosion by 1.5 Tg C yr-1. We find that about 50% of this increase is remineralized on the shelves and released to the atmosphere. Another 30% get deposited in near-shore sediments, whereas 10% are exported to the open ocean via advection, and 10% reside in the shelf waters as accumulating DIC. This means that the anthropogenically induced increase in coastal erosion reduced the CO2 uptake during the past century by 0.8 Tg C yr-1 (3% of the total uptake by Arctic shelves) and may further weaken the CO2 sink of the Arctic Ocean as global warming continues.