bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving Agricultural Nitrogen Use Efficiency to Reduce Air Pollution in China
Authors: Luo Biao , Tai Amos P. K.
Published: March 2024

Chinese agriculture has long been characterized by low nitrogen use efficiency (NUE) associated with substantial ammonia (NH3) loss, which contributes significantly to fine particulate matter (PM2.5) pollution. However, the knowledge gaps in the spatiotemporal patterns of NH3 emissions and the states of nitrogen management of agricultural systems render it challenging to evaluate the effectiveness of different mitigation strategies and policies. Here we explored the NH3 mitigation potential of various strategies and its subsequent effects on PM2.5 pollution, and their effectiveness in improving NUE of Chinese agricultural systems. We developed and used a nitrogen flow model for evaluating NUE of different crop and livestock types at a provincial scale in China. We then used the bottom-up NH3 estimates to drive an air quality model (GEOS-Chem High Performance, GCHP) to provide an integrated assessment of four improved nitrogen management scenarios: improving NUE of crop systems (NUE-C), increasing organic fertilizer use (OUR), improving NUE of livestock systems (NUE-L) and combined measures (COMB). The total agricultural NH3 emission of China was estimated to be 11.2 Tg NH3 in 2017, of which 46.24% and 53.76% are attributable to fertilizer use and livestock animal waste, respectively, and emission hotspots can be identified in the North China Plain. Our results show that grain crops have higher NUE than fruits and vegetables, while high livestock NUE can be found in pork and poultry, and NUE for the entire crop and livestock systems are both better in Northeast China than the rest of China. We also found that agricultural NH3 emissions can be reduced from 11.2 Tg to 9.1 Tg, 9.3 Tg, 9.9 Tg and 6.8 Tg, and consequently annual population-weighted PM2.5 reductions are estimated to be 1.8 µg m–3, 1.6 µg m–3, 1.3 µg m–3 and 4.1 µg m–3 under NUE-C, OUR, NUE-L and COMB scenarios, respectively. Our results are expected to provide decision support policy making concerning agricultural NH3 emissions.
Not as Rare as Expected: Assessing Singapore’s Unprecedented Droughts in a Changing Climate
Authors: Peng Xiao , Long Biao , He Xiaogang
Published: March 2024

There has been growing evidence suggesting a rising frequency and/or intensity of droughts in tropical regions in a warming climate. Singapore, a water-scarce city heavily reliant on water imports, faces heightened vulnerability to extreme drought episodes. Preparing for unprecedented droughts is thus pivotal for this tropical island city to safeguard a sustainable and resilient water supply. However, the accuracy of quantifying the probability and severity of unprecedented droughts, such as those with a 1000-year return period, is hindered by observations (e.g., in situ measurements, satellite data, etc.) with limited data length, typically spanning only about 50 years. Physics-based regional climate models offer a distinct advantage in simulating extreme droughts beyond historically available data. Yet, naïve Monte Carlo simulations for rare events becomes computationally infeasible at high spatiotemporal resolutions, a scale most relevant in urban drought risk mitigation. In this study, building upon the Giardina-Kurchan-Lecomte-Tailleur algorithm, we develop a computationally efficient framework to simulate Singapore’s unprecedented drought events. Our framework couples the Weather Research and Forecasting (WRF) model with a sequential importance sampling procedure, incorporating the ‘Darwinian pressure’ to favor trajectories conducive to extreme drought conditions. With just slightly over 100 trajectories, we can efficiently simulate very rare drought events (e.g., 1-in-10000-years and rarer) while maintaining their physical plausibility. The WRF model also enables detailed spatiotemporal dynamics of unprecedented droughts, allowing direct estimation of potential compounding extremes, such as concurrent droughts and heatwaves. Moreover, we quantify changes in the likelihood of plausible yet unprecedented droughts under various future climate change scenarios, such as Shared Socioeconomic Pathway 5-8.5 (SSP585), in comparison to the present climate. Our results reveal a robust increase in the chance of unprecedented droughts, emphasizing the importance of developing resilient water strategies for Singapore to prepare for such events in the near future.
Tropical SST Impacts on the Subtropical Atmospheric Circulation and Regional Precipitation
Authors: Qiu Weiteng , Collins Mat , Scaife Adam , Santoso Agus
Published: March 2024

The tropical Pacific Ocean hosts the Earth’s most prominent year-to-year climate fluctuation, the El Niño-Southern Oscillation (ENSO), which exerts strong impacts on remote regions of the globe through atmospheric teleconnection. In this study, we use reanalysis data and Coupled Model Intercomparison Project Phase 6 (CMIP6) historical simulations to investigate the relationship between tropical and subtropical atmospheric circulation, and the tropical SST patterns and regional precipitation.   We find dynamical relationships between subtropical high intensity, the Hadley and Ferrel Circulation intensity, and the Eady Growth Rate from the reanalysis. A poleward shift of the maximum in Eady Growth Rate is associated with a strengthening of the descending branches of the Ferrel and Hadley Cells, with subtropical troposphere adiabatic warming and an increased intensity and poleward movement of the subtropical highs. Shifts in the poleward Eady Growth Rate are dominated by changes in vertical wind shear which, in turn, are in thermal wind balance with variations and trends in temperature. The mechanism for the intensification of the subtropical highs involves feedbacks from high-frequency transient eddies. Strong North Pacific and South Pacific Subtropical highs are associated with La-Niña conditions. We also show that the mechanisms for interannual variations are similar to those for trends in the highs.We further analysed the performance of the coupled models in reproducing the trends (1979-2014) of the tropical zonal wind and regional precipitation. The CMIP6 historical simulations do not capture the intensification of trade winds within the Niño 4 region, and they also fail to reproduce the statistically significant precipitation trends over the Southern North America and the Amazon. However, a linear adjustment, based on ENSO teleconnections, can be applied to the coupled models to make the precipitation trends much closer to observations. The relationship between SST patterns and precipitation trends are confirmed by looking at atmosphere-only simulations. This study provides further evidence of the importance of reconciling observed and modelled SST patterns in the tropical Pacific.
Nanoscale Wettability of Oil/Rock Interface and its Impact on Occurrence and Flooding
Authors: Fan JiaNing , Wang FengChao
Published: March 2024

Mineral wettability plays a pivotal role in determining residual oil distribution and devising effective displacement strategies for enhanced oil recovery. Through molecular dynamics simulations, we investigated the surface wettability of various typical minerals, revealing the complete spreading of modeled crude oil over most mineral surfaces. Our research introduces an efficient method for calculating the spreading coefficient of modeled crude oil on mineral surfaces, allowing accurate predictions of its spreading state with a notable reduction in calculation time compared to traditional methods. Furthermore, the study explores the impact of various components within crude oil on mineral surface wettability, emphasizing microscopic interactions between these components and minerals. In nanopore channels, the diverse wettability of oil/rock interface results in varied occurrence forms, such as droplets, films, or columns, which are also different in the water flooding process. In addition, with the introduction of various components in crude oil, due to their different interactions with oil/water/rock, we found that these components can be evenly mixed with modeled crude oil or exist at the oil-water interface. Therefore, the introduction of this component changes the properties of oil-water interface, affects the form of oil occurrence and the process of flooding. These insights contribute to a comprehensive understanding of mineral surface wettability and its correlation with crude oil composition, providing valuable guidance for optimizing reservoir management and refining production strategies in the pursuit of enhanced oil recovery.
The analysis and evaluation of rainfall events of different durations in the Tibetan Plateau
Authors: Ling Xiaoyan , Chen Yingying , Yang Kun , Li Xin , Zhou Xu
Published: March 2024

The Tibetan Plateau, known as the 'Asian Water Tower,' has drawn significant attention to its hydrological cycle and associated atmospheric dynamics. The Qiang-tang Plateau, located in the northern part of the Tibetan Plateau's  endorheic basin (hereinafter referred to as the plateau), experiences notable climate and water cycle variations. The spatial characteristics of its precipitation determine the spatial patterns of hydrological elements and ecological environments in the Qiang-tang Plateau. However, its harsh environment and challenging conditions for station establishment have resulted in a severe scarcity of precipitation observation data. Presently, mainstream reanalysis products consistently overestimate precipitation levels on the plateau and fail to accurately simulate daily precipitation variations. To address this, utilizing data from 206 tipping-bucket rain gauges deployed across the plateau from 2017 to 2020, the study investigates rainfall events of different durations: short-term (1-3 hours), medium-term (4-6 hours), and long-term (7 hours or more).The research reveals that the precipitation intensity at plateau sites is generally low, with short-term rainfall events being predominant. However, the contribution of short-term rainfall events increases spatially from the southeast edge to the inland of the plateau. Notably, the Qiang-tang Plateau exhibits a significantly higher proportion of short-term precipitation compared to other regions on the plateau. Furthermore, based on a newly established mountainous precipitation transect, it was discovered that as one ascends from the Gangdisi Mountains to the Qiang-tang Plateau, the contribution of short-term rainfall to the total precipitation significantly increases with elevation. Additionally, an analysis of mainstream reanalysis products (ERA5, MERRA2) and high-resolution model simulation data (HAR2) for different duration rainfall events indicates that reanalysis products consistently underestimate the contribution of short-term precipitation while overestimating long-term precipitation. HAR2 outperforms ERA5 specifically in the Qiang-tang Plateau and the northeast part of the plateau, whereas MERRA2 fails to capture the spatial heterogeneity of different duration rainfall events. Although reanalysis products can capture the diurnal peak of short-term precipitation, they tend to prematurely estimate the diurnal peak of long-term precipitation.
Surface silicate distribution in the Chukchi-shelf region during the Arctic summer cruises using programmable flow injection technique
Authors: Hatta Mariko , Davis Madeline , Measures Chris
Published: March 2024

The surface Arctic Ocean is subject to rapidly changing freshwater inputs, from increasing ice melt and riverine inputs. Close monitoring of inflow waters from the Pacific and Atlantic is also needed for understanding the balance of geochemical cycles and making future predictions in the Arctic.  However, our knowledge of ocean biogeochemical data is very limited, necessitating an expansion of spatial and temporal coverage. However, the acquisition of ocean samples is hindered by the intricate sampling and analytical procedures employed both at sea and on land.In our recent work [Hatta et al, 2021; 2023], a miniaturized, automated, microfluidic analyzer for nutrient analysis was developed using the programmable flow injection (pFI) technique.  This innovative system achieves accurate measurements with minimal reagent use, computer-controlled manipulations, and auto-calibration techniques, thus it is a promising oceanographic tool for increasing sample acquisition and determination, as well as minimizing human error.  For the pFI technique, the traditional silicate (Si) molybdenum blue method was modified by combining oxalate and ascorbic acid into a single reagent. This new method obtained a limit of detection of 514 nM Si, r.s.d. 2.1%, sampling frequency rate of 40 samples per hour, reagent consumption of 700 microliters per sample, and use of deionized (DI) water as a carrier solution. Phosphate (P) does not interfere significantly in this technique if the Si:P ratio is 4:1 or larger. Additionally, since there is no salinity influence, samples collected from the open ocean, coastal areas, or rivers can all be determined accurately using a DI water-based standard calibration covering a single small range by diluting samples to fall within this limited range.In this contribution, this new shipboard method using programmable Flow Injection will be presented along with high-resolution Si data from the Chukchi shelf.  These data were obtained every 10-20 minutes by directly connecting the pFI platform to the underway water sampling system during the RV Mirai summer cruises. This new analytical platform will allow us to significantly expand our database and thus help to constrain and quantify geochemical processes and budgets in the Arctic Ocean.
Modelling the conditions that may lead to phreatic eruptions, with comparison to Whakaari volcano, New Zealand
Authors: Pearson-Grant Sophie , Köpping Jonas , Patterson James , Driesner Thomas
Published: March 2024

Phreatic or steam-driven eruptions are the most common type of volcanic eruption in New Zealand. They are notoriously difficult to forecast and have caused fatalities globally. There are two main conceptual models that have been proposed to lead to phreatic eruptions: a) cracking of a hydrothermal seal that is trapping pressurised fluid, and/or b) an injection of hot magmatic gas interacting with cold groundwater that then flashes to steam resulting in rapid fluid overpressure and overburden failure. Testing these hypotheses can help to determine the subsurface processes and timescales leading to an eruption, a possible key to unlocking phreatic eruption forecasting.We have created generalised 2D numerical models of heat and fluid flow based on conceptual models of Whakaari/White Island volcano in New Zealand. Using CSMP++, we have explored the conditions that allow a build-up of fluids with sufficient overpressure to cause rock failure and potentially initiate an eruption. Our models simulate a sealed hydrothermal system above a magma reservoir. In some models, there is a high permeability zone linking the two which represents a highly fractured zone inferred from fumarole and degassing locations at Whakaari. A subset of these models also includes low permeability zones on either side of the highly fractured zone, which correspond to inferred regions of hydrothermal alteration.Model results suggest that the permeability of the rock affects how quickly fluids move, but not the long-term pressure distribution. Our models show pressure increases of more than 5 MPa beneath the hydrothermal seal purely due to magmatic heating of groundwater. However, the timescales are on the order of decades. If low-permeability alteration zones are included which limit lateral flow of fluids, pressure increases by 5 MPa from hydrostatic in less than two years. We are now exploring the effects of adding magmatic fluids as well as heat, and will compare results of these models with field and experimental observations from Whakaari volcano.
The British Virgin Islands in the Caribbean Evolution: Petrogeochemical and geochronological constraints
Authors: Bosc Noémie , Bosch Delphine , Philippon Mélody , Noury Mélanie , Bruguier Olivier , Montheil Lény , van Hinsbergen Douwe , Cornée Jean Jacques
Published: March 2024

The British Virgin Islands (BVI) is a NE-SW trending archipelago located in the northeastern corner of the Caribbean plate. Exposing volcanic arc rocks, it is located at the junction between the old arc of the Greater Antilles to the Northwest and the active arc of the Lesser Antilles to the South. The BVI are a key location to study the geodynamical evolution of the northeastern boundary of the Caribbean plate. In order to understand its significance into the overall Caribbean evolution, a set of 16 igneous samples from seven islands was studied for petrology, geochemistry (major and trace elements, and Pb-Sr-Nd-Hf isotopes), thermobarometry (Al-in-hornblende) and U-Pb geochronology on accessory minerals (zircon, titanite and apatite). The studied rocks show a typical volcanic arc signature and correspond to a calc-alkaline series, differentiated along a NE/SW gradient. Trace elements patterns show strong negative HFSE anomalies and LILE enrichments. ɛHfi are homogeneous ranging from +11.4 to +14.1 typical of a MORB-type mantle. Magmas were thus originated from a homogeneous mantle corresponding to the mantle wedge, with participation of a slab component. The slab component contribution is estimated to be less than 2% and is dominated by aqueous fluids, except for Peter and Norman Islands. U-Pb ages emphasize an active magmatic period spanning between ~43 Ma and ~30 Ma along a NE-SW younging gradient. This age range and strong geochemical similarities with arc lavas exposed in St Martin and St Barthélémy suggest that the BVI represent the northern continuity of the Eo-Oligocene extinct branch of the Lesser Antilles arc. Crystallization depth of the studied plutonic bodies, estimated by thermobarometric constraints, supports a NE-SW increasing emplacement depth from ~7km to ~13km. The oldest plutonic bodies at NE thus experienced less total exhumation than the youngest plutonic bodies at SW (maximum rate of ~2.2 mm/yr at SW and minimum rate of ~0.2 mm/yr at NE). From Eocene to Oligocene it has been recently demonstrated that the block from Puerto Rico-Virgin Islands (PRVI) rotated 45° counter clockwise (Montheil et al., 2023). Previous thermochronological data shows that the BVI exhumation occurred synchronously along the archipelago between ~25 and ~21 Ma (Román et al., 2021). Together these observations suggest a regional tilt of the BVI block that occurred between plutons crystallisation and their exhumation at ~2 km depth. We propose that the tilting and the fast exhumation of the BVI, that are synchronous with counterclockwise rotation of the PRVI block, are the consequence of subduction locking generated by the Bahamas bank accretion to the northeastern Caribbean plate.
Coseismic slip distribution of the 2023 earthquake doublet in Turkey and Syria from joint inversion of Sentinel-1 and Sentinel-2 data: An iterative modeling method for mapping large earthquake deformation
Authors: Chen Jianlong , Zhou Yu
Published: March 2024

Interferometric synthetic aperture radar (InSAR) decorrelation that creates great challenges to phase unwrapping has been a critical issue for mapping large earthquake deformation. Some studies have proposed a “remove-and-return model” solution to tackle this problem, but it has not been fully validated yet, and therefore has rarely been applied to real earthquake scenarios. In this study, we use the 2023 Mw 7.8 and 7.6 earthquake doublet in Turkey and Syria as a case example to develop an iterative modeling method for InSAR-based coseismic mapping. We first derive surface deformation fields using Sentinel-1 offset tracking and Sentinel-2 optical image correlation, and invert them for an initial coseismic slip model, based on which we simulate InSAR coseismic phase measurements. We then remove the simulated phase from the actual Sentinel-1 phase and conduct unwrapping. The simulated phase is added back to the unwrapped phase to produce the final phase measurements. Comparing to the commonly-used unwrapping method, our proposed approach can significantly improve coherence and reduce phase gradients, enabling accurate InSAR measurements. Combining InSAR, offset tracking and optical image correlation, we implement a joint inversion to obtain an optimal coseismic slip model. Our model shows that slip on the Çardak Fault is concentrated on a ~100 km segment; to both ends, slip suddenly diminished. On the contrary, rupture on the East Anatolian Fault Zone propagated much longer as its geometry is fairly smooth. The iterative coseismic modeling method is proven efficient and can be easily applied to other continental earthquakes.
Investigating the drivers of global glacier volume changes over the last two decades using machine learning
Authors: Diaconu Codrut-Andrei , Bamber Jonathan L. , Maussion Fabien , Zekollari Harry
Published: March 2024

Machine learning plays an increasingly important role in modelling and better quantifying observed changes in various subcomponents of the Earth system. For instance, in the field of glaciology, machine learning methods have the potential to help unravel the ever-growing datasets on observed glacier changes, allowing for a better understanding of these changes and their driving factors.In this study, we investigate the benefit of using a non-linear machine learning framework to model the observed recent glacier changes (individual glaciers’ geodetic mass balance over the 2000-2019 period) for nearly all the land-terminating glaciers larger than 2 km^2. To this end, we build a Random Forest model driven by a set of predictors, composed of both topographic (e.g. area, slope, debris coverage) and climatic features (e.g. temperature and precipitation anomalies), which explain up to 70% of the global variance in the observational dataset. Generally, we find that the climatic features are more important, explaining alone approx. 55% of the variance, as compared to the approx. 40% obtained with the topographical ones alone. We further investigate the importance of the topographical predictors within subregions that are assumed to be climatically homogeneous, showing different behaviours across them.Our study illustrates the benefit of using non-linear models when statistically modelling multi-decadal geodetic mass balances, providing further insights into the drivers of current glacier changes. The proposed framework also has the potential to be used as a gap-filling tool to estimate the geodetic mass balance of unmeasured glaciers or those with uncertain geodetic mass balance observations and to predict future mass balance when forced with CMIP6 climate data or similar Earth System Model output.
Large discrepancy between observed and modeled wintertimetropospheric NO2 variabilities due to COVID-19 controls in China
Authors: Chen Jiaqi , Jiang Zhe , Miyazaki Kazuyuki , Jones Dylan
Published: March 2024

Recent studies demonstrated the difficulties to explain observed tropospheric nitrogen dioxide (NO2) variabilities over the United States and Europe, but thorough analysis for the impacts on tropospheric NO2 in China is still lacking. Here we provide a comparative analysis for the observed and modeled (Goddard Earth Observing System-Chem) tropospheric NO2 in early 2020 in China. Both ozone monitoring instrument and surface NO2 measurements show marked decreases in NO2 abundances due to the 2019 novel coronavirus (COVID-19) controls. However, we find a large discrepancy between observed and modeled NO2 changes over highly polluted provinces: the observed reductions in tropospheric NO2 columns are about 40% lower than those in surface NO2 concentrations. By contrast, the modeled reductions in tropospheric NO2 columns are about two times higher than those in surface NO2 concentrations. This discrepancy could be driven by the combined effects from uncertainties in simulations and observations, associated with possible inaccurate simulations of lower tropospheric NO2, larger uncertainties in the modeled interannual variabilities of NO2 columns, as well as insufficient consideration of aerosol effects and a priori NO2 variability in satellite retrievals. In addition, our analysis suggests a small influence from free tropospheric NO2 backgrounds in E. China in winter. This work demonstrates the challenge to interpret wintertime tropospheric NO2 changes in China, highlighting the importance of integrating surface NO2 observations to provide better analysis for NO2 variabilities.
A Linearized Coupled Model of Acoustic-gravity Waves and the Lower Ionosphere at Mars
Authors: Wang Xing , Xu Xiaojun , Cui Jun , Yi Siqi , Gu Hao , Zhou Zilu , Man Hengyan , Luo Lei , He Peishan , Yang Pu
Published: March 2024

Highly variable ionospheric structures on Mars have been recently observed via spacecraft measurements. Acoustic-gravity waves (AGWs) could be an underlying mechanism. Studying the response of the Martian ionosphere to AGWs could provide us with an important understanding of the neutral wave-ionospheric coupling process. To explore the plasma-neutral coupling driven by AGWs in the lower ionosphere of Mars, a linearized wave model has been developed. This model can describe the propagation and dissipation of AGWs in a realistic atmosphere and first incorporates plasma behaviors associated with photochemistry and electromagnetic fields. We adopted a full-wave model as the first part of our coupled model to delineate wave propagation in a realistic atmosphere. The second part of our model consists of the governing equations describing the plasma behaviors. Therefore, our model not only replicates the result of the full-wave model but also investigates the wave-driven variations in the plasma velocity and density, electromagnetic field, and thermal structures. Our model results reveal that ions are mainly dragged by neutrals and oscillate along the wave phase line below ~200 km altitude. Electrons are primarily subject to gyro-motion along magnetic field lines. The wave-driven distinct motions among charged particles can generate the perturbed electric current and electric field, further contributing to localized magnetic field fluctuations. Major charged constituents, including electrons, O+, O2+, and CO2+, have higher density amplitudes when interacting with larger-periodic waves. The presence of photochemistry leads to a decrease in the plasma density amplitude, and there exists a moderate correlation between plasma density variations and those in the neutrals. Our numerical results indicate that the wave-driven variations range from several percent to ~ 80% in the plasma density and from ~ 0.2% to 17% in the magnetic field, which are consistent with the spacecraft observations. Further calculations reveal that the wave-induced plasma-neutral coupling can heat the neutrals yet cool the plasmas. Electrons are cooler than ions in the coupling process. The wave-driven heating by neutral-ion collisions exceeds that by neutral-electron collisions but tends to be lower than the wave dissipative heating and photochemical heating. Our model has potential applications in studying the AGWs-driven variable ionospheric structures and can be used for other planets.
Equilibrium (reversible) and nonequilibrium (permanent) fracture in rock: equilibrium statistical mechanics theory and experiments, and physical/intuitive analysis of common nonequilibrium fracture modes
Authors: Keanini Russell ,   US, Israel, UK, Japan, France Rock Fracture Collaboration
Published: March 2024

Macroscopic equilibrium statistical mechanics is first used to interpret and predict thermally driven microfracture in rock. Application of the theoretical framework to three heating and cooling experiments, performed on granite and reported between 1989 and 2017, provides strong evidence that the temperature-, pressure- and volume-dependent average microfracture population within a given rock volume can be treated as an equilibrium thermodynamic variable.  This observation, in turn, suggests that thermoelastic microfracture, in rock and similar granular solids, can be predicted and interpreted using standard, process- and history-independent equilibrium thermodynamics.  In order to place equilibrium rock fracture and healing in context, we then consider nonreversible, permanent, i.e., nonequilibrium fracture. Here, pictorial, physical, and quantitative analyses of several common, thermally driven rock fracture processes are presented, including: a) terrestrial thermal exfoliation of single grains from diurnally heated rock surfaces, b) non-terrestrial thermal exfoliation of thin, near surface rock layers, as recently observed, e.g., on Bennu, c) terrestrial and non-terrestrial thermally-driven through cracking, and d) initiation of c).  We show how the form of the continuum momentum and energy conservation equations for thermoelastic materials – here, rock- provides a powerful, intuitive framework for quickly visualizing and roughly predicting the fracture/weathering processes in a) through d).
Space weather today: From an Earth-centred discipline to a heliosphere-wide field of research
Authors: Palmerio Erika
Published: March 2024

Space weather, i.e. the conditions in space driven by the dynamic solar activity, is a terminology that has been traditionally used to refer to the Sun’s effects on the near-Earth environment. This is because of a rather obvious reason, namely that most of the technological systems susceptible to space weather conditions and all human beings are currently on Earth or in near-Earth space. Hence, space weather research and forecasting efforts have focussed for decades mainly on our own neighbourhood. Nevertheless, in more recent years there has been a paradigm shift, due to which the field of space weather science has been gradually evolving into a heliosphere-wide discipline. This has been motivated by two main factors: (1) a growing interest in human exploration outside the Earth–Luna system, with efforts centred especially on Mars, and (2) an increasing endeavour from the research community to view the solar system as a Sun–heliosphere–planets integrated environment.In this presentation, we will first provide a brief overview of the more “traditional” approach of space weather science to studying the Sun and its transient phenomena—e.g., the structured solar wind, coronal mass ejections, and solar energetic particles. We will then showcase more recent efforts that have been centred on taking advantage of data from missions scattered throughout the solar system to analyse space weather events at multiple points in the heliosphere and their effects on different planetary environments. Finally, we will highlight current and future opportunities for advancing our knowledge of the Sun and space weather-driving phenomena across the heliosphere. Particular emphasis will be given to possible synergies between different subjects of solar system science—i.e. solar, heliospheric, and planetary—and to ideas for the future in terms of multi-disciplinary space missions that can improve our understanding of space weather phenomena from a fundamental physics standpoint and, at the same time, that can expand our knowledge of space weather drivers and effects at other locations than Earth.
Assessing urban heat mitigation strategies in Singapore with a Digital Urban Climate Twin (DUCT)
Authors: Wong Minn Lin , Zozaya Ander , Orehounig Kristina
Published: March 2024

Addressing the urban heat island effect requires informed and strategic planning of measures to mitigate urban heating. This is particularly important for highly urbanized and densely populated cities in the tropics, such as Singapore, which experience high levels of thermal discomfort due to urban heat island effect, and is further intensified by global warming. To assess the impact and effectiveness of different heat mitigation measures, we utilize a Digital Urban Climate Twin (DUCT) model of Singapore. The DUCT integrates the Weather and Research Forecasting model and Building Energy Model (WRF/BEM), with an added modification to account for near-surface anthropogenic heat sources such as power plants and traffic emissions. Next to these models the DUCT also integrates various data sources such as weather conditions, landcover, buildings, traffic etc. to describe the thermal behaviour of the city.In this study, we use the DUCT to conduct a comprehensive testing of the sensitivity of urban temperatures to various heat mitigation measures such as increasing urban greenery, changing urban morphology and improvements in building efficiencies and traffic. Preliminary results indicate that designating forest land use and incorporating green areas are the most effective in reducing local and surrounding temperatures. This is followed by increasing the urban vegetation fraction in the pre-existing urban landscape, increase in electric vehicle usage, and improvements in building energy efficiencies, which show a more limited impact on temperatures. This work aims to highlight the capabilities of the DUCT as a versatile tool for planning agencies and policy makers to test the effectiveness of various policies and guide strategic planning for the management of urban heat.
First steps into Water-Energy-Food-Ecosystem Nexus Transition in semiarid depopulated regions: A case of study in the Spanish Duero basin. 
Authors: Segovia-Cardozo Daniel Alberto , Sánchez-Bayo Gonzáles María , Vallejos Mihotek Mara , Schneider Xenia , Rodriguez-Sinobas Leonor
Published: March 2024

Water scarcity and water stress have become a concern for many countries worldwide, especially to Mediterranean countries like Spain. Which, together with the increase in energy prices, have affected food production and degraded ecosystems. Over the last two decades in Spain, irrigated areas have expanded in the interest of modernizing irrigation systems to cope with increased food consumption and to promote economic development and the maintenance of the rural population. At the same time, managing – rising fertilizer and energy prices and water scarcity have become necessities, but also threatening the natural ecosystem. Until now Water, Energy, Food, and Ecosystems (WEFE) challenges have been traditionally managed independently, contrary to the international community recommendation of treating them together in a WEFE Nexus framework to address their interrelationships and achieve a balance. Considering this framework, two workshops took place in the Duero Basin in Spain with the stakeholders, from the different WEFE entities, aiming at promoting and co-defining WEFE-Nexus transition actions for addressing the WEFE-Nexus challenges and for improving the local WEFE-Nexus conditions. As a first step, the WEFE-Nexus transition requires active engagement and building trust among WEFE stakeholders and as a second step to involve them in a co-creation process with knowledge’s exchange and mutual learning. Thus, the Responsible Research and Innovation (RRI) was applied through the RRI Roadmapãä for co-defining WEFE-Nexus transition actions or plan to improve local WEFE-Nexus conditions and identifying knowledge, technical and scientific gaps and how to bridge them to be successful. The first workshop used storytelling and the participatory method of the World Café to actively engage and motivate the stakeholders. The second workshop was performed from an expert point of view and a NEXUS NESS- Serious Game to foster discussion and create awareness on sustainable management practices; it focused on water-energy resource management, agricultural production, and the impact of climate change.The methodology and the results from both workshops are presented in this paper.
Long-term evolution of the subsurface water environment on Mars over the past million years
Authors: Kamada Arihiro , Kuroda Takeshi , Watanabe Yasuto , Kobayashi Mirai , Kodama Takanori , Greve Ralf , Nakagawa Hiromu , Kasaba Yasumasa , Terada Naoki
Published: March 2024

Mars is an extremely cold and dry planet today, but it is thought to have been a water-rich planet in the past. Most of the water reservoir could represent hydrated crust and/or ground ice interbedded within sediments. Unlike Earth, Mars does not have a large satellite, so its obliquity varies greatly, and atmospheric circulation, water circulation, and subsurface water distribution are expected to change significantly over time. Currently, water ice is unstable at the pressure-temperature conditions found at the surface or subsurface of low/mid-latitude Mars, but recent observations by SHARAD revealed that large amounts of water remain beneath Utopia Planitia, which is thought to have formed during periods of high obliquity.Here, we have newly developed a fully coupled global water circulation model for the atmosphere, hydrosphere, and cryosphere down to a depth of 1 km in the subsurface, and we used an iterative time integration scheme. We performed a series of simulations with changing Martian obliquity and eccentricity over the last few million years, and north polar layer deposit as an initial water reservoir. Our model implemented a water exchange scheme between the atmosphere and the regolith/crust for different porosities and grain sizes. We found that in the recent Milankovitch cycle, during the smaller obliquity periods, subsurface ice was mainly distributed around higher latitudes, but during the larger obliquity periods, the distribution of subsurface ice extended to lower latitudes of around 40° N. It is possible that water ice with a volume content of more than 10% may remain at high latitudes above 60° N. The abundance of water at such high latitudes could be an important indicator in the search for possible life on Mars, or a valuable water resource in future manned Mars missions.
Effect of Wetting and Drying Cycles on the Stability of Cadmium and Zinc Immobilized with Ferrihydrite 
Authors: Kim Chaeyoung , Nam Kyoungphile
Published: March 2024

 The repetitive wetting and drying cycles, driven by intense rainfall and drought, intricately alter subsurface conditions, affecting redox states and pH levels. Consequently, these alterations may prompt the dissolution or transformation of ferrihydrite (Fh), an amorphous iron oxide used as a stabilizing agent in soil, thereby influencing the leaching behavior of heavy metals. This study investigates the impact of wetting and drying cycles on Fh crystallinity, and the leaching behavior of immobilized heavy metals, specifically focusing on cadmium (Cd) and zinc (Zn) at Fe/heavy metals molar ratios of 1 and 10. Fh synthesis was induced by neutralizing pH to 7.0 with 1 M NaOH, simultaneously fostering the coprecipitation of Fh-heavy metals. The experimental design entailed 12 cycles, each involving 8 hours of wetting at room temperature, followed by 16 hours of drying at 40 °C. The Synthesis Precipitation Leaching Procedure (SPLP) was then used to confirm the variations in leaching quantities observed throughout the cycles, following the guidelines of EPA METHOD 1312. Analyses using X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) revealed distinct variations in morphology and crystallinity based on the type and ratio of heavy metals. Pure ferrihydrite remained stable after 12 cycles; however, heightened crystallinity emerged after 3 cycles in high heavy metal concentrations, forming otavite (CdCO3) in Cd samples and petalline-shaped ferrihydrite in Zn samples. In contrast, low heavy metal concentrations displayed no such changes, indicating variable effects of wetting-drying cycles depending on the iron-to-heavy-metals ratio. The supernatant concentration decreased by 11-37% during wetting in all samples, yet SPLP leaching tests exhibited consistent heavy metal concentrations between wetting and drying, suggesting a minimal impact on heavy metal stability. These findings underscore the environmental factors influencing the stability of iron oxide-based immobilized heavy metals and raise the need for long-term stability assessments to consider variables that can cause more complex changes in the field. 
Exploring Drought Patterns in the Headwaters of the Tarim River Basin through an Integrated Surface-Groundwater Drought Index
Authors: Yu Xiaohan , Zeng Xiankui , Gui Dongwei , Wang Dong , Wu Jichun
Published: March 2024

The Tarim River Basin, China's largest inland river, has been grappling with persistent drought challenges. Over 90% of its water resources originate from the headwaters, heavily relying on groundwater. Existing drought indices often compartmentalize considerations of surface water and groundwater variables. Consequently, there is a necessity for a comprehensive drought index that accounts for the interplay between surface water and groundwater. This study employs the Copula function to formulate the Standardized Precipitation Evapotranspiration Groundwater Index (SPEGI), incorporating surface water (precipitation minus evaporation) and groundwater (changes in total water storage observed by GRACE satellite minus changes in output from the VIC model). SPEGI is computed using a moving average approach across various time scales (1, 3, 6, 12 months) and is juxtaposed with traditional indices such as Standardized Precipitation Evapotranspiration Index (SPEI), Standardized Soil Moisture Index (SSMI), and Standardized Groundwater Index (SGI). The findings underscore that SPEGI, grounded in the integrated consideration of surface and groundwater variables, provides a more comprehensive depiction of drought conditions in the study area. In contrast to traditional indices, SPEGI not only accounts for short-term precipitation and evaporation changes but also effectively reveals the characteristics of groundwater fluctuations. Additionally, by comparing SPEGI with NDVI data, the study delves into the desertification process in the region. The research discerns that SPEGI's assessment of drought resilience is more sensitive, manifesting an increasing trend in the desertification process with the enlargement of SPEGI's sliding window. Overall, this research contributes novel methodologies and empirical evidence for fostering sustainable water resource utilization and informing climate change adaptation decisions within the basin.
Absence of surface volcanism and the indeterminate evidence for continental mantle plumes
Authors: Pilia Simone , Iaffaldano Giampiero , Davies Rhodri , Sossi Paolo , Whattam Scott , Hu Hao
Published: March 2024

There are rare occurrences on Earth where mantle plumes intersect with continents, resulting in surface volcanism.Unlike their more common counterparts in oceanic lithosphere, where the ascent of melts is facilitated by a thinner lithosphere, identifying continental plumes is challenging. Surface volcanism, traditionally a key indicator of mantle plumes, may play a diminished role in regions characterized by complex tectonics and variations in lithospheric thickness.Eastern Oman provides an excellent example where a continental mantle plume has remained undetected due to the absence of current surface volcanism. The region exhibits evidence of intraplate basanites, although with an age of ~35-40 Ma. Given their geochemical signature, these alkaline rocks likely originated from a mixture of melts from a plume-derived source and those from a lithosphere-derived component. Using P- and S-wave arrival-time residuals from distant earthquakes, we image a new mantle plume in eastern Oman, which we name the Salma plume. This continental plume is revealed in our 3-D P- and S-wave tomographic models as a 200 km low-velocity conduit extending to at least the base of the upper mantle, and located below the area of Tertiary intraplate volcanism. Despite experiencing minimal shortening since the Paleogene, the shallow-marine sediments of the Salma Plateau in eastern Oman reach elevations exceeding 2000 meters. Ongoing uplift, indicated by elevated Quaternary marine terraces, suggests that the plateau is still rising. The present uplift rate is modest but maps of residual topography show a positive trend in eastern Oman that can be associated to the presence of a plume.Incorporating a geodynamic perspective, our analysis of noise-mitigated Indian plate motion relative to Somalia reveals that India underwent a constant-velocity reorientation of approximately 15˚  from 48 to 30 Ma, concurrent with the arrival of the plume head beneath eastern Oman. We quantitatively demonstrate that increased asthenospheric flow induced by the plume flux in eastern Oman, adjacent to the Indian plate in the Eocene, may be responsible for deflecting the Indian plate path, as indicated in kinematic reconstructions.The consequence of ignoring a plume in Oman is that we were unable to understand many of the enigmatic observations from plume impingement at ~40 Ma. Our study underscores the potential of combining seismology, geology, geochemistry, and geodynamics to be a more effective approach for detecting continental plumes than relying solely on surface volcanism, and has transformed our understanding of the tectonic evolution of the area and beyond.
A dynamical alternative for simulating multi-scale high-resolution sub-daily space-time precipitation for future climates
Authors: Sharma Ashish , Kim Youngil , Evans Jason
Published: March 2024

How can climate model simulations for the future generate high-resolution sub-daily precipitation that could be trusted for a range of hydrologic design applications? This is a question that often provokes contradicting responses from climate scientists and hydrologists. Our study attempts to unify the knowledge gained from these two disciplines to present the first ever alternative for generating multi-scale (low-to-high frequency temporal persistence), high resolution (down to 1km if needed), sub-daily precipitation for future climates that is dynamically consistent with concurrent climate forcings (including atmospheric moisture, circulation patterns) and local topography. This dynamical precipitation generator contains three components. The first component is the raw temporal resolution climate field simulated using global climate models on the lower and the lateral boundaries of the spatial domain precipitation simulations are needed for. The second component is SDMBC, an innovative alternative for correcting systematic biases at Sub-Daily (SD) time steps, using the Multivariate Bias Correction (MBC) approach which corrects multivariate dependence, persistence and distributional attributes across variables that form the lateral and lower boundaries of the domain of interest. The third and final component is a Regional Climate Model (RCM), chosen to be the Weather Research and Forecasting (WRF) model for the present study, which uses the corrected lateral and lower boundary forcings generated from the second component of our framework, and generates dynamically consistent sub-daily precipitation along with other physically consistent atmospheric variables at high-resolution. It is shown here that use of this framework simulates precipitation fields that exhibit features consistent with observations including observed extremes, and storm events that are consistent with our expectations of how precipitation extremes will evolve in future (warmer) climates. A Python software (named SDMBC) that simplifies the implementation of the bias correction process is presented, and results are shown for simulations across the Australian domain. This software is now available from (https://pypi.org/project/sdmbc/) and can be used for applications over any domain worldwide in conjunction with WRF models that have been formulated independently.