bluuebunny/crossref_metadata_2025 huggingface dataset:
Multi-Objective Calibration of Nile River Basin Using Recovered Records
Authors: Munyejuru Irenee Felix , Stagge James
Published: March 2024

The transboundary Nile River Basin (NRB) occupies a tenth of the African continent and supports the daily livelihood of approximately 300 million people in 11 riparian countries. The NRB is hydrologically complex: two major watersheds, the Blue and White Nile, contribute about 85% of the total annual discharge; more than 50 % of the White Nile’s water is lost over the Sudd wetland; and the Blue and White Nile watersheds produce dramatically different seasonal hydrologic responses due to differences in hydroclimate and lake/wetland storage. The Inter-Tropical Convergence Zone (ITCZ) drives anomalies in temperature and precipitation; however, this atmospheric driver likely produces distinct hydrologic responses that depend on the spatial center over the Blue or the White Nile headwaters. Quantifying this effect requires a well-calibrated hydrologic model of the entire watershed under near-natural conditions, including hydrologic routing through major lakes and the Sudd wetland. This study aims to calibrate such a hydrologic model and recreate the hydrologic response of the major watersheds in the NRB using recovered records that extend to 1901, thereby greatly increasing the period used for model calibration and approximating near-natural responses prior to construction of several modern reservoirs. We employed GR4J, a parsimonious rainfall-runoff hydrologic model, because of its flexibility and minimal data requirements to match the NRB’s limited data availability, particularly during the early 1900s. Climate drivers, including precipitation and daily minimum/maximum temperatures were based on the Global Soil Wetness Project Phase 3 (GSWP3). Discharge data for model calibration were acquired from the Global Runoff Data Centre (GRDC) and through digitization of long discharge records from Hurst (1958). The NRB was discretized into 36 hydrological response units (HRUs), and calibrated using stepwise, multi-objective approach at 16 gauge locations between 1901 and 1964. In addition to avoiding the effects of several modern reservoirs, this early calibration period also avoided the most severe effects of climate change, as supported by the lack of discernible trends using the Mann-Kendall test. Our results show a successful calibration of the GR4J hydrological model to reasonably reproduce discharge at multiple locations across the NRB, with Nash-Sutcliffe Efficiencies of 0.83 and 0.64 at the outlets of the Blue and the White Nile, respectively. Additionally, the calibrated model accurately captured an abrupt change of Lake Victoria levels during the 1960s, affirming its reliability in simulating regional climate disruptions and lake dynamics. The model can therefore be used to study the sensitivity of major watersheds in the NRB and serves as a benchmark for understanding anthropogenic-induced departures from the natural hydrological behavior of the Nile River.Keywords: Nile River Basin, GR4J, Calibration, Hydrology
Interpreting transboundary water resources system operation using machine learning
Authors: Yang Guang , Giuliani Matteo , Castelletti Andrea , Dong Zengchuan
Published: March 2024

Water reservoirs serve vital roles in energy and food security through storage for hydropower generation and food production. Multiple reservoirs are typically used in a river basin to meet growing demands. To promote cooperative reservoir operation and mitigate water use conflicts, it is important to understand how operational decisions develop in time and interact, especially when considering multiple operating objectives. Interpreting multi-purpose, multi-reservoir dynamics is particularly challenging in transboundary contexts, where interdependencies develop across multiple riparian countries. To address this problem, we develop a model-agnostic interpretation framework to explain water systems globally and locally using machine learning methods. Specifically, we use the Gradient Boosting Regression Tree to approximate reservoir operation policies and combine it with recursive feature elimination to select the most important features or input variables in reservoir operation decision-making. We also attribute specific optimized reservoir decisions to the selected input variables using the Shapley additive explanation method and further explain their dependencies by examining the partial dependence plots of reservoir release decisions on water availability and water demand. Using a case study of cascade reservoir operation in the Nile River Basin, we elucidate trade-offs between power generation and irrigation water supply in Ethiopia, Sudan, and Egypt and interpret the relationship among reservoir operation decisions, water availability, and water demand in the Nile River Basin system.
Our results show that the trade-offs between power generation and water supply in the Nile Basin are strongly related to the decision-making criteria of the different objectives (the criteria here represent the riparian countries' requirements for the performance of the Nile operation). For example, the conflict between power generation from the High Aswan Dam (HAD) and irrigation water supply in Sudan is evident regardless of the power generation output, whereas the conflict between power generation from the HAD and irrigation water supply downstream of the HAD becomes evident and difficult to mitigate only when considering a certain criterion of HAD power generation (i.e. HAD power generation is required higher than 860 GWh/month). In addition, the most important features or input variables selected for the operation of each reservoir in the Nile system vary significantly with operational performance and decision preferences. By incorporating the proposed framework, we can select the most important features in multi-objective water system operations and infer the relationship between operational decisions, water availability, and water demand at each time step.
Multi-model assessment of the deglacial climatic evolution at high southern latitudes 
Authors: Obase Takashi , Menviel Laurie , Abe-Ouchi Ayako , Vadsaria Tristan , Ivanovic Ruza , Snoll Brooke , Sherriff-Tadano Sam , Valdes Paul , Gregoire Lauren , Kapsch Marie-Luise , Mikolajewicz Uwe , Bouttes Nathaelle , Roche Didier , Lhardy Fanny , He Chengfei , Otto-Bliesner Bette , Liu Zhengyu , Chan Wing-Le
Published: March 2024

The quaternary climate is characterised by glacial-interglacial cycles, with the most recent transition from the last glacial maximum to the present interglacial (the last deglaciation) occurring between ~ 21 and 9 ka. While the deglacial warming at southern high latitudes is mostly in phase with atmospheric CO2 concentrations, some proxy records have suggested that the onset of the warming occurred before the CO2 increase. In addition, southern high latitudes exhibit a cooling event in the middle of the deglaciation (15–13 ka) known as the Antarctic Cold Reversal (ACR). In this study, we analyse transient simulations of the last deglaciation performed by six different climate models as part of the 4th phase of the Paleoclimate Modelling Intercomparison Project (PMIP4) to understand the processes driving southern high latitude surface temperature changes. While proxy records from West Antarctica and the Pacific sector of the Southern Ocean suggest the presence of an early warming before 18 ka, only half the models show a significant warming (~1 °C or ~10 % of the total deglacial warming). All models simulate a major warming during Heinrich stadial 1 (HS1, 18–15 ka), greater than the early warming, in response to the CO2 increase. Moreover, simulations in which the AMOC weakens show a more significant warming during HS1 as a result. During the ACR, simulations with an abrupt increase in the AMOC exhibit a cooling in southern high latitudes, while those with a reduction in the AMOC in response to rapid meltwater exhibit warming. We find that all climate models simulate a southern high latitude cooling in response to an AMOC increase with a response timescale of several hundred years, suggesting the model’s sensitivity of AMOC to meltwater, and the meltwater forcing in the North Atlantic and Southern Ocean affect southern high latitudes temperature changes. Thus, further work needs to be carried out to understand the deglacial AMOC evolution with the uncertainties in meltwater history. Finally, we do not find substantial changes in simulated Southern Hemisphere westerlies nor in the Southern Ocean meridional circulation during deglaciation, suggesting the need to better understand the processes leading to changes in southern high latitude atmospheric and oceanic circulation as well as the processes leading to the deglacial atmospheric CO2 increase.
Inversion of Upstream Solar Wind Parameters from Tianwen-1 H-ENA Observations at Mars
Authors: Zhang Yiteng , Li Lei , Xie Lianghai , Kong Linggao , Li Wenya , Ma Jijie , Tang Binbin , Qiao Fuhao , Wang Limin , Jin Taifeng , Zhang Aibing
Published: March 2024

An algorithm has been developed to invert the solar wind parameters from the hydrogen energetic neutral atom (H-ENA) measured in near-Mars space. Supposing the H-ENA is produced by change exchange collision between protons that originated in the solar wind and neutrals in the exosphere, an H-ENA model is established based on the magnetohydrodynamic (MHD) simulation of the solar wind interaction with Mars, to study the H-ENA characteristics. It is revealed that the solar wind H-ENAs are high-speed, low-temperature beams, just like the solar wind, while the magnetosheath H-ENAs are slower and hotter, with broader energy distribution. Assuming Maxwellian velocity distribution, the solar wind H-ENA flux is best fitted by a Gaussian function, from which the solar wind velocity, density, and temperature can be retrieved. Further investigation, based on the ENA flux simulated by the H-ENA model, reveals that the accuracy of inversed solar wind parameters is related to the angular and energy resolutions of the ENA detector. Finally, the algorithm is verified using the H-ENA observations from the Tianwen-1 mission. The upstream solar wind velocity when inversed is close to that of the in situ plasma measurement. Our result suggests the solar wind parameters inversed from H-ENA observation could be an important supplement to the dataset supporting studies on the Martian space environment, where long-term continuous monitoring of the upstream SW condition is lacking.
Counterflow and entrainment within a buoyant plume-fed asthenosphere
Authors: Li Xianyu , Shao Jia , Wang Guanzhi , Shi Yanan , Morgan Jason
Published: March 2024

Laboratory and numerical experiments and boundary layer analysis of the entrainment of buoyant asthenosphere by subducting oceanic lithosphere (cf. Morgan et al., Terra Nova, 2007) implies that slab entrainment is likely to be relatively inefficient at removing a buoyant and lower viscosity asthenosphere layer. Such asthenosphere would instead be mostly removed by accretion into overlying oceanic lithosphere, both at mid-ocean ridges where a ~60-km compositional lithosphere forms due to the melt-induced dehydration of upwelling peridotitic mantle, and later with the thermal growth of  overlying oceanic lithosphere. When an oceanic plate subducts, the lower (hot) side of a subducting slab entrains a 10– 30 km-thick downdragged layer, whose thickness depends upon the subduction rate and the density contrast and viscosity of the asthenosphere, while the upper (cold) side of the slab may entrain as much by thermal ‘freezing’ onto the slab as by mechanical downdragging.  Here we use 2-D numerical experiments to investigate the dynamics of entrainment and counterflow at subduction zones. We explore situations with both stable subduction geometries and slab rollback. Due to its low viscosity, a plume-fed asthenosphere is particularly likely to be stratified in its internal density, with variable amounts of plume melt-extraction leading to variable pyroxenite fractions and associated vertical density stratification within a bilithologic ~80-90% peridotite, ~10-20% pyroxenite asthenosphere. While this type of vertical density stratification appears to lead to similar predicted entrainment by subducting slabs, it will generate more complex patterns of asthenospheric counterflow that involve shallower and time-dependent counterflow behind the subducting slab.
Geospatial patterns in surface water parameters and recent land use change in the karst of Samcheok, South Korea
Authors: Lumongsod Regina Martha , Kim* Heejung
Published: March 2024

Karst landscapes develop distinct surface landforms intricately connected to a more complex subsurface drainage system due to the highly soluble nature of its bedrock. Because of this, surface processes can more directly affect the groundwater system through conduits such as caves and sinkholes. Due to high hydraulic conductivity, aside from surface and groundwater, the soil produced from weathering and erosion of karst is also affected. Samcheok, found in southeastern Gangwon Province, is an example of an area that is underlain by limestone-bearing formations, allowing the formation of karst. In this study, the patterns in the hydrochemical characteristics of surface water and the land use of areas adjacent to the streams in Samcheok karst were explored through geospatial analyses. Additionally, recent land use change in the area was also investigated. Surface waters from four streams in Samcheok were analyzed: Osipcheon River, Yeosam Stream, Sohan Stream, and Gyogok River. Results show that hydrochemical parameters in northeast Samcheok karst are mostly varied and to an extent dependent on the stream where the samples were taken from more than the sampling distance from the coast. Usual patterns for pH and dissolved oxygen in terms of salinity were not observed. Concentrations of cations and anions mostly varied between the two sampling seasons (winter and spring for February and April 2020 samples, respectively) and were also varied in terms of linear correlation for concentration vs. distance to stream outlet graphs. High linear correlation was observed for spring samples from Gyogok River for the following ions: Ca2+ (R2 = 0.976), Mg2+ (R2 = 0.9321), SO42- (R2 = 0.879), and HCO3- (R2 = 0.955). More than 50% of the area adjacent to streams is classified as “other bare land”. Between 2019 and 2020, there was an increase in the total land area for coniferous forests and a decrease in mixed forest and undeveloped arable field. Research on geospatial patterns for hydrochemical parameters and land use change in environments susceptible to pollution such as karst areas are useful for land use planning and erosion studies. This research was funded by the Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education (Nos. 2019R1I1A2A01057002, and 2019R1A6A1A03033167) and the Korea Ministry of Environment as "The SS (Surface Soil conservation and management)” project (No. 2019002820004).
3D-time slab deconstruction and ore deposit localization in South America
Authors: Nakrong Nipaporn , Forster Marnie , Spakman Wim , Jelsma Hielke , Lister Gordon
Published: March 2024

Here we present a 3D-time reconstruction of the tectonic evolution of the Nazca and South American plates. The geometry of subducted slabs was modelled down to a depth of ~1950km using UU-P07 global tomographic model. Our approach integrated geochronological records, geological history, and seismotectonic data. Furthermore, our proposed slab models incorporated both velocity and temperature gradients to determine the mid-slab surface accurately. To reconstruct these slabs with minimal distortion back to the Earth's surface, we employed a reverse engineering method. The positions of potential tears in the subducted slabs can then be recognized by the induced distortions. We identified at least three down-dip tears, which significantly influence subduction behaviour. We then integrated the floated or pre-subducted slabs into a 2D-time tectonic reconstruction and tracked the subduction interface over time. Our reconstruction reveals that the pre-subducted slabs accurately mimic the shape of the Andes during the Oligocene-Miocene boundary. However, the remnants of slabs subducted before that time are no longer connected to the entire slab. To the north of the Nazca tear, which coincides spatially with the Nazca fracture zone, the continuous slab has subducted to a depth of ~1950km. To the south, the downgoing slab has been segmented into three distinct zones, with tears localized along the two arms of the extrapolated Juan de Fernández ridge and the inferred Challenger fracture zone. Moving from north to south, the slab in these zones detached at some point after 22Ma, 15Ma, and 12Ma, respectively. Each slab segment exhibits variations in geometry, with flat slab and steep slab portions, as well as differences in penetration depth. Notably, the location of the Nazca down-dip tear coincides with the initial location of the eastward spanning of the Cu belts.
Assemblage of satellite information to produce insights into ground-water storage in Colombia’s five major basins
Authors: Romero Pedro , Piña Adriana
Published: March 2024

Measuring the existing amount of groundwater in a specific region is no easy task. It is well known that this resource is one of the hardest to acquire and at the same time it is close to one third of existing freshwater on the earth. Satellite data stands as a convenient source of information in developing countries where groundwater levels monitoring remains scarce, but groundwater pressure keeps rising because of the increase of population and global climatic changes.In this work, satellite data from the World GRACE Land Water Equivalent and GLDAS Terrestrial Water Storage measurement programs were downloaded and processed using the programming language Python. By applying a simple hydrological balance and masking the worldwide downloaded information to Colombia’s extent, groundwater anomalies were estimated. Different representations were used in order to comprehend groundwater anomalies data under its possible scopes: geographic, temporal, and extreme value analysis were made for the Colombian region and its five major basins, finding useful information about each region like average, minimum, and maximum values; time-related behavior was observed in early and late times from measurement timestamps; extreme value heat maps allowed us to identify historical geographic outlier regions; a mean value heat map was generated for the full time span of measurement as a reference value for each region; finally, a combined scope helped us identify extreme events geographically and temporally.As a result, among the observations studied since the first GRACE mission in 2002, until the last downloaded information in February 2023, the Pacific basin showed the least fluctuations in groundwater storage anomalies. This behavior can be attributed to the high precipitation rates in this region and likely the soil's saturation state. Meanwhile, in the Caribbean region, the fluctuations were significant, with a strong tendency toward groundwater depletion. This unique behavior may be linked to the region's geographic exposure to climatic phenomena like El Niño/La Niña.Lastly, leveraging diverse perspectives on groundwater, we conducted focused seasonal analyses to comprehend its behavior under El Niño and La Niña conditions. We also performed a brief comparison to assess the resemblance between precipitation patterns and groundwater estimations. Considering the Oceanic Niño Index (ONI) for the 2009-2012 La Niña period, groundwater anomalies were generally positive across all studied basins. Conversely, during the 2014-2017 El Niño period, anomalies were predominantly negative, particularly in the Caribbean and Magdalena Cauca basins, highlighting their vulnerability to these climatic phenomena.
Investigating Model Forecast Bias for Rainfall Produced by Slantwise Ascent above Cold High
Authors: Hu Ning , Fu Jiaolan
Published: March 2024

Moderate to heavy rain produced by slantwise ascent of moist air above the cold high is prevalent in cold season in East China. The slantwise ascent is usually characterized by a southwest moist flow aroused by the so-called southern branch trough of 500hPa level to the south of the Qinghai-Tibet Plateau, while the cold high is usually formed by cold air damming, which is familiar to weather forecasters due to topographic feature of East China. The routine short-range forecast skill for this kind of precipitation of weather forecasters is usually limited by model performance. Through large sample model verification, our study indicates that, for the rainfall produced by southwesterly moist flow ascending above the cold high, the ECMWF model always underestimates the rainfall amount on the northeastern part of the rainfall belt, which could be taken as a systematic bias of the state-of-the-art global model. Our case studies indicate that the underestimation of rainfall amount is related to the weaker slant ascent of moist southwest flow forecast by ECMWF model than observation or reanalysis. The southwest flow above the northeastern flow induced by the cold high forms strong wind shear and warm-moist advection, which favors the occurrence of conditional symmetric instability producing strong slantwise ascent not well reflected by global model.
Study on Soil Physical Properties of Terraced Slope Farmland in Black Soil Region of Northeast China.
Authors: Wei Siyu , Fu Yu
Published: March 2024

To explore the soil water holding capacity and soil structure on sloping farmland with terrace measures in Black Soil Region of Northeast China. The construction of terraces slope farmland in different soil types (Black soil, Dark brown soil and Brown soil) is taken as the research object, the slope farmland (non- terraced slopes) was used as a blank control (CK). In the study, the spatial uniform distribution method was used to quantify the soil water holding capacity, soil structure characteristics and spatial distribution characteristics of construction of terraced slope farmland. The results showed that (i) the physical properties of soil after terrace construction in Black Soil Region were better than that of CK, and the improvement degree was Brown soil > Black soil > Dark brown soil. (ii) Compared with the CK, the soil physical properties of Brown soil in terrace slope farmland were improved obviously. The soil saturated water holding capacity of terrace slope farmland increased by 10.24 %. Besides, the soil capillary water holding capacity of terrace slope farmland increased by 16.77 %, and the soil field water holding capacity of terrace slope farmland increased by 16.10 %. Compared with the CK, the soil structure characteristics of Brown soil in terrace slope farmland were also more stable, and he total soil porosity and capillary porosity of terraced slope farmland increased by 9.14 % and 15.56 %. (iii) Terraced slope farmland of Brown soil mainly affect soil moisture characteristics and soil porpsity, in which soil capillary water holding capacity with 12.11 % of contribution rate, and the contribution of terraces to total soil porosity was 11.21 %. The main influencing factors of terraces in Dark brown soil were soil structure characteristics, in which the contribution of soil total porosity was 13.84 %, and the contribution of water-stable aggregate content was 13.31 %, which were greater than that of CK ; The contribution rate of each index of terrace of Black soil is relatively uniform, at 10.24 % -12.5 %. In summary, the terraces of Brown soil affect the characteristics of soil moisture and soil structure. The terraces of Dark brown soil mainly affects the characteristics of soil structure. Terraces of Black soil mainly affect soil moisture characteristics.Keywords : black soil region; terraces; soil water holding capacity ; characteristics of soil structure
How does vegetation restoration affect the soil quality on the Loess Plateau? A meta-analysis
Authors: Geng Wenliang , Duan Shunxia , Li Yangyang , Zhang Xiaoping , Hudek Csilla
Published: March 2024

Abstract: Soil degradation is one of the biggest environmental problems facing the earth today, with which more than 33% of the earth’s soil currently degraded. Soil erosion is considered to be one of the dominant and prevalent form of soil degradation in the developing countries. The Loess Plateau is the areas with the most serious soil erosion in China and even in the world. A number of literatures showed that vegetation restoration was one of the most effective measures in controlling soil erosion and preventing soil degradation. But the effects of vegetation restoration across climate, vegetation types and restoration years are not clear. A meta-analysis was conducted and achieved 1731 paired observations from 71 peer-reviewed papers to improve the understanding of the effects of vegetation restoration on soil quality and to identify the factors influencing its changes.       The results showed that: (1) The literatures are distributed in various provinces of the Loess Plateau, with the most concentrated distribution in northern Shaanxi Province. In terms of specific data, the relevant data covered several aspects of soil quality indicators, such as Bulk density (n=180), Soil total porosity (n=91), Soil aggregate stability (n=65), Soil organic matter (n=180), Total nitrogen (n=166), Total phosphorus (n=112), Available nitrogen (n=47), Available phosphorus (n=63), Microbial biomass carbon (n=46), Microbial biomass nitrogen (n=29), Microbial biomass phosphorus (n=20), and others.       (2) Compared with the farmland, after vegetation restoration on the Loess Plateau, soil bulk density was significantly reduced by 6-10 %, soil total porosity was significantly increased by 12-16 %, soil aggregate stability was significantly increased by 18-24 %, soil saturated hydraulic conductivity was significantly increased by 12-18 %, soil organic carbon and total nitrogen content was significantly increased by 47-55 % and 43-52 %, microbial biomass carbon, nitrogen, phosphorus and enzyme activity were also significantly increased.       (3) The effect of vegetation restoration on soil quality mainly depends on soil texture, vegetation type and restoration year. Generally, the effect of forest on soil quality is higher than that of shrub and grass. The effect of vegetation restoration on soil quality increases with the increase of vegetation restoration years.       The results of the study provide a basis for the evaluation of the ecological effects of vegetation restoration in the Loess Plateau, and can provide a reference for the selection of reasonable vegetation allocation methods under different restoration conditions, thereby improving soil degradation in arid and semi-arid areas.Keywords: Vegetation restoration; Soil quality; Meta analysis; Loess Plateau
Comprehensive Analysis of a Type III Radio Storm Using Multi-Spacecraft Observations
Authors: Krupar Vratislav , Kruparova Oksana , Szabo Adam , Lario Loyo David
Published: March 2024

Solar flares are often accompanied by intense radio emissions, particularly notable in the form of fast-drifting type III bursts. These bursts are generated by suprathermal electron beams that are accelerated at solar flare reconnection sites. These electron beams travel outward along open magnetic field lines, passing through the corona and interplanetary medium. Type III Radio Storms, characterized by nearly continuous type III radio burst activity, can persist for hours or days. This study reports on a significant type III storm observed between 2023-09-20 and 2023-09-27, observed simultaneously by STEREO-A and Parker Solar Probe. During this interval, the spacecraft were longitudinally separated by 5 to 45 degrees, providing a unique opportunity to examine both radial and longitudinal variations in type III storms. Additionally, the Solar Orbiter's position on the opposite side of the Sun, complemented by SDO data, enabled nearly 360-degree solar coverage in EUV during this event. This extensive coverage allowed for the correlation of individual radio bursts with EUV images, offering a comprehensive view of the full Sun. Our findings contribute to the understanding of solar flare dynamics and electron beam propagation in solar eruptions.
Using XGBoost & SHAP feature importance to understand the drivers of the Southern Ocean cloud-radiation bias
Authors: Fiddes Sonya , Mallet Marc , Protat Alain , Woodhouse Matthew , Alexander Simon , Furtado Kalli
Published: March 2024

The Southern Ocean radiation bias has been a multigenerational problem in climate and weather models. This radiation bias, where too much sunlight is allowed to reach the surface, has been attributed to the incorrect simulation of cloud properties, particularly their phase. Allowing too much sunlight to reach the surface of the Southern Ocean has significant effects both locally (e.g. sea surface temperatures) and globally.
Traditional model evaluation techniques of the Southern Ocean often focus on one particular cloud type or synoptic situation or have been limited temporally or spatially. Additionally, it is difficult to quantify non-linear relationships with more traditional evaluation techniques. In this work, we present an evaluation of the Southern Ocean cloud-radiation bias using an XGBoost model and SHapley Additive exPlanations feature importance analysis. We propose that this method can provide as much information as traditional evaluation techniques and more by handling large data sets and non-linear relationships.
We find that our XGBoost model can explain 55% of the summertime daily cloud radiative bias of the entire Southern Ocean (1x1˚ grid) over 5 years, where biases in cloud properties are used as predictors. Using SHAP feature importance we find that the bias in cloud liquid water path is the most important predictor, though this varies by cloud type and latitude, and that the SHAP feature analysis can identify and quantify important complex relationships. We also show that this method can be useful in evaluating model perturbations, in particular with respect to how changes in a model may impact different clouds or regions in a different way. Overall, we suggest that this method can be used to evaluate large and complex systems in a holistic way, streamlining model evaluation and development testing.
Understanding Ni-Cu Sulphide Deposits in a Plate Tectonic and Mantle Convection Context
Authors: Page Isadora , Mather Ben R. , Januszczak Nicole , Anthony Michele , Muller R. Dietmar
Published: March 2024

Nickel-Copper (Ni-Cu) sulphide deposits are a diverse class of deposits, formed during the cooling and crystallisation of metal-rich mafic to ultramafic magmas. Despite sharing several key ore-forming processes, many of these deposits form in contrasting geologic environments and periods. The objective of this research project is to investigate the spatial and temporal distribution of Ni-Cu sulphide deposits in a mantle convection and plate tectonic context, and to explore the influence of different mantle and tectonic parameters on their origins and occurrence. We first determine the location of these deposits in relation to relevant geologic and tectonic features through time, including subduction zones, large igneous provinces (LIPs), and mantle plumes. Using a 1 billion year plate model we extract key parameters relating to subduction, as well as the spatio-temporal distribution of LIPs through time. Employing an associated geodynamic model, we identify model mantle plumes and quantify their key properties. Preliminary findings indicate that certain mantle plumes associated with deposits exhibit increased plume flux in the upper mantle preceding deposit formation, and that many deposits are spatially associated with LIPs throughout their formation history. For several deposits located in convergent margin settings, we have identified a notable spike in subduction volume and convergence rate during a 50-100 million year period prior to the onset of mineralisation. While the angle of the subducting slab is highly variable throughout the evolution of these deposits, several deposits are associated with a distinct steepening of the subducting plate in the lead-up to deposit formation. The findings of this study aim to contribute new insights into the dynamic processes governing the genesis of magmatic Ni-Cu sulphide deposits. These insights aid in our understanding of the interplay between mantle dynamics, plate tectonics, and deposit formation, and hold implications for future critical mineral exploration.
From River to Reservoir: Exploring Phytoplankton Dynamics and Its Environmental Correlates in the Xiangjiaba Channel-Type Reservoir
Authors: Wang Xinlu , Sun Jian , Lin Binliang
Published: March 2024

Mega reservoirs, such as the Three Gorges Reservoir on the Yangtze River, have garnered significant attention due to their environmental impacts. However, the ecological ramifications of upstream Cascade Reservoirs remain understudied, despite their potential influence on the Yangtze River ecosystem. This study delves into the phytoplankton community and environmental factors of the Xiangjiaba Reservoir (XJB), a significant reservoir on the Yangtze River mainstream. Field surveys and laboratory analysis were conducted to identify factors driving algae distribution and temporal shifts. The phytoplankton exhibited dominance changes among different phyla. Bacillariophyta and Chlorophyta dominated throughout the year, while Cryptophyta prevailed in spring and Xanthophyta peaked in autumn, indicating a unique feature of the area. The water quality in XJB was moderate. The average chlorophyll-a exhibited significant spatial-temporal variations, peaking at 26 ug/L at the mainstream-tributary confluence. Since the reservoir's construction in 2006, an overall tenfold increase in algae density and a shift from Bacillariophyta-dominated system to a more diverse multi-phylum-dominance have been observed. Hydrodynamic conditions played a pivotal role, with water stratification favoring flagellated algae like Chlorophyta and Cryptophyta. Differences in phytoplankton composition between XJB and the Three Gorgeous Reservoir were linked to the latter's pronounced vertical mixing. The study underscores the swift hydrodynamic adaptations post-construction, juxtaposed with the slower biological (phytoplankton) responses, emphasizing the need for sustained monitoring to ensure the reservoir's ecological balance. This research offers insights into the ecological impacts of reservoir construction, highlighting the role of hydrodynamics in reservoir ecosystems and aiding in understanding reservoir functioning, water quality management, and biodiversity conservation.
Soil and carbon accumulation rates in different ecological types of mangroves in a karstic region (Celestún, Yucatán)
Authors: Canul Cabrera Jesús Andrés , Herrera Silveira Jorge Alfredo , Díaz Asencio Misael , Pech Poot Eunice , Gasser Beat , Masque Pere
Published: March 2024

Mangroves, as well as other coastal ecosystems, perform a fundamental role as sinks of carbon in their soils for long periods of time (hundreds to thousands of years). This capacity for sequestering carbon is controlled by several factors, such as mesoscale meteorology, structural complexity of the forest, hydrological regimes, and microtopography. Therefore, quantifying the carbon on these forests is fundamental to understand their potential for climate change mitigation and local adaptation. The Ria Celestun Biosphere Reserve is a natural protected area located in a karstic region in Mexico with a shallow slope and a strong environmental gradient that allows the presence of different ecological types of mangroves. Based on the analysis of sedimentary cores collected in mangrove areas and dated with the 210Pb method, we assessed the soil and carbon accumulation rates in the upper 50 centimeters in four ecological types of mangroves (fringe, basin, dwarf and peten). According to preliminary results, basin mangrove dominated by Rhizophora mangle and Avicennia germinans showed higher values of carbon stocks (360 MgCha-1), than fringe and peten mangroves (240 MgCha-1 and 270 MgCha-1, respectively). Taking into account gaps in mangrove knowledge in karst regions and among mangrove associations, the results could be used as a tool for decision-making and priority-setting of conservation actions.
Simulating glacier evolution with a 3D ice sheet model
Authors: Leguy Gunter , Lipscomb William , Minallah Samar
Published: March 2024

We have implemented a new framework for simulating the dynamic evolution of mountain glaciers in the Community Ice Sheet Model (CISM), a 3D, higher-order ice sheet model that serves as the ice dynamics component of the Community Earth System Model. We have used CISM to simulate all the glaciers of the European Alps at a resolution of 100 m. We describe the modeling framework and present results for the third phase of the GlacierMIP project (GlacierMIP3), which aims to determine the equilibrium area and volume of all glaciers outside the ice sheets, if global mean temperatures were to stabilize at present-day or various warmer levels. Compared to other glacier models, CISM is relatively sensitive to warming. We project that Alpine glaciers will lose a majority of their area and volume under present-day temperatures, with nearly complete ice loss under warmer scenarios. We are extending this framework to other glacier regions and will show preliminary result.
Persistent Near-Roadway Air Quality Disparities in California Despite Widespread Zero-Emission Vehicle Adoption
Authors: Wen Yifan , Yu Qiao , He Yueshuai , Ma Jiaqi , Zhu Yifang
Published: March 2024

The adoption of zero-emission vehicles (ZEVs) offers multiple benefits for the climate, air quality, and public health by reducing tailpipe emissions. However, the environmental justice implications of the non-exhaust emissions from future ZEV fleets for near-roadway communities remain unclear. Here, we model the on-road fine particulate matter (PM2.5) emissions across all California counties and assess the near-roadway exposure disparities at the census block group level in Los Angeles County in 2050, when almost all passenger vehicles are projected to be ZEVs. We found that although heavy-duty trucks (HDTs) represent only 7% of on-road traffic in LA County, ZEV policies targeting HDTs provide more benefits than those aimed at light-duty vehicles (LDVs). In both the state and LA County, ZEV promotion in HDT fleets generates more favorable benefits for disadvantaged communities compared to LDV fleets. In LA County, the most disadvantaged 25% of the population experiences 36% and 44% of the total environmental benefits from promoting zero-emission LDVs and HDTs, respectively, which is 2.4 and 3.7 times higher than the benefits shared by the least disadvantaged quantile. Despite the progress in benefiting marginalized populations through ZEV promotion, disparities persist due to the remaining brake and tire wear emissions and increased HDT traffic in disadvantaged communities. We recommend implementing fleet-specific ZEV policies to address brake and tire wear emissions, as well as optimizing freight structures, to address these persistent environmental justice issues in California.
Coexisting Agriculture, Industry, and Energy in Rural Areas： Comparative Surrounding Surface Temperatures between Rooftop Solar Panels and Iron Rooftop in the Yunlin
Authors: Lee Yi-Jing , Chung Ming-Kuang , Tseng Wan-Ling
Published: March 2024

In Taiwan's rural areas, significant changes are underway in the once-predominant focus on traditional agriculture. The current landscape in rural areas is characterized not only by the presence of numerous factories but also by the increasing solar panels, driven by the ongoing transition to renewable energy sources. Despite numerous studies confirming the correlation between land use and temperature in urban areas, limited thermal research has been conducted in rural regions. Additionally, rural residents, particularly the elderly, are more sensitive to temperature variations.The purpose of this study is to investigate whether the construction of iron rooftop factories and rooftop solar panel structures in rural environments results in significant differences in surface temperature and surrounding land use, thereby revealing the thermal impacts of these structures.Three coastal towns in central Taiwan were selected as the primary study area due to their higher density of solar panels and similar agricultural characteristics. Landsat 8 surface temperature data were utilized, with buffer zones established at 30-meter intervals from sample boundaries to explore variations in surface temperature and land use characteristics.The findings reveal that rooftop solar panels and iron factories are predominantly surrounded by arid fields. As the distance from rooftop solar panels increases, the surface temperature gradually decreases, returning to ambient levels. However, no discernible changes in surface temperature were observed around iron rooftop factories. This study not only sheds light on the thermal impacts of these structures in rural environments but also points out the importance of land use control on thermal environments.
Development of a Comprehensive Exposure-at-Risk Map for Europe: Integrating Coinciding Natural Hazards and Exposure Metrics
Authors: Daniell James , Schaefer Andreas , Claassen Judith , Brand Johannes , Tiggeloven Timothy , Khazai Bijan , Girard Trevor , Maier Annika , Blanz Benjamin , Strelkovskii Nikita , Mysiak Jaroslav , de Ruiter Marleen , Jaeger Wiebke , Ward Philip
Published: March 2024

The development of an Exposure-at-risk map for Europe that encompasses multiple coinciding natural hazards builds upon many previous attempts and existing portals such as TIGRA, TEMRAP, ESPON, JRC DRMKC, and GIRI to name a few, which have primarily focused on examining a few single hazards and limited exposure.The novelty of this approach lies in its integration of a myriad of hazards into a single, cohesive framework. The European Hazard Map is constructed using data from various sources, covering geophysical hazards (earthquakes, volcanoes, landslides), meteorological hazards (winds, convective storms, storms), hydrological hazards (river/pluvial floods), climatic overlaps (bushfires, droughts), and biological hazards. These hazards are modelled using both stochastic and probabilistic methods as well as historical reanalysis, offering a robust and comprehensive view of potential risks.The exposure component of this map is constructed around a handful of key Europe-wide metrics, encompassing aspects crucial to the European multi-sector context. These include tourism-based metrics such as domestic and international expenditure, hotel statistics, employment figures, as well as broader economic indicators like capital stock (particularly focusing on buildings), GDP, and critical infrastructure related to transport and energy. Additionally, agricultural production and seasonal population variations are factored in. These metrics are pivotal in assessing the potential impact of various hazards, including but not limited to earthquakes, tsunamis, winds, floods, landslides, tornadoes, hail, droughts, and bushfires.This map has been developed as part of the MYRIAD-EU project, a multi-hazard initiative, and is built using open data sources and risk analytics within the project. A significant feature of this map is its ability to demonstrate temporal and spatial overlaps. This capability allows for the visualization of combined events or the combined impact of different exposure-hazard overlaps, depending on whether the output is stochastic or probabilistic. The interface of this map serves as a crucial gateway to the MYRIAD-EU multi-hazard software scorecard approach. It also plays a pivotal role in identifying overlapping hazards within the EU, enabling better preparedness and response strategies.In summary, this Exposure-at-risk map for Europe is a significant advancement in the field of hazard assessment and risk management. It integrates a multitude of hazards and exposure metrics, offering a comprehensive and detailed view of potential risks across Europe. This map is not only a tool for current risk assessment but also a foundation for future research and development in this critical area of study.
Ab initio study of the conductivities of B2 FeSi under core-mantle boundary conditions
Authors: Huang Yonghui , Li Yunguo , Ni Huaiwei
Published: March 2024

While the ultralow velocity zones (ULVZs) may hold key information about deep earth dynamics, their elusive state and origin remain as an enigma. Recently, high pressure experiments indicate that ULVZs may form from the B2 FeSi phase crystallized from the outer core containing H and Si. The possibility and impact of the B2 FeSi at the core mantle boundary (CMB) awaits further exploration. The conductivity of the B2 phase can be used to understand its role in deep mantle dynamics and also served as a test for its existence at the CMB. By using first-principles molecular dynamics and Kubo-Greenwood formula, we calculated the thermal and electrical conductivities of B2 FexSi1-x at 135 GPa up to 4,500 K. Our results show that at the CMB conditions, the thermal and electrical conductivities of B2 FeSi are significantly higher than other lower mantle minerals and the core. This would lead to a thermal anomaly region at the CMB, promote the core dynamo and enhance the cooling of the core if the ULVZs are dominated by B2 phase.
Autogenic Formation of Bimodal Grain Size Distributions in Rivers and its Contribution to Gravel-sand Transitions
Authors: An Chenge , Parker Gary , Venditti Jeremy , Lamb Michael , Hassan Marwan , Miwa Hiroshi , Fu Xudong
Published: March 2024

Riverbeds fine downstream and often have a gravel-bedded reach, a relatively abrupt gravel-sand transition (GST), and a sand-bedded reach. Underlying this behavior, bed grain size distributions are often bimodal, with a gap around the range 1-5 mm. Despite several viable theories, there is no morphodynamic model capable of producing the grain size gap and gravel-sand transition autogenically from a unimodal sediment supply. Here we use a one-dimensional morphodynamic model including size-specific bedload and suspended load transport, to show that bimodality readily evolves autogenically even under unimodal sediment feed. A GST forms when we include in the simulation a floodplain width that abruptly increases at some point. Upstream of the transition, non-gap gravel ceases to move and gap sediment is preferentially transported. At the transition, non-gap sand rapidly deposits from suspension, enhancing gap sediment mobility and diluting its presence on the bed.