bluuebunny/crossref_metadata_2025 huggingface dataset:
Mobile observations of air pollution characteristics and source tracking : the case of Megacity Chengdu, China
Authors: Hu Hancheng , Wu Hao
Published: March 2024

Precise pollution control and source tracking have been commonly used due to the development of portable on-line sampling instruments. This study investigated the spatial distribution characteristics of pollution during a local pollution period in the Shuangliu district of Chengdu, China. The persistent particle size distributions and ozone concentrations in the Shuangliu district were recorded using a mobile observation platform. The three-dimensional spatial and temporal changes in the aerosol size distributions and ozone concentrations were obtained by means of a portable optical particle profiler (POPS), a PO3M ozone detector, a hand-held meteorological station, and a Laser wind lidar. The results indicate that during polluted episodes, the daily particle number concentration (PNC) values ranged from 7,967.63 to 16,342.31 #·cm-3, compared to 4,290.87 to 11,039.61 #·cm-3 during clean episodes. The results revealed that human activities and meteorological conditions were the primary causes of local pollution. Regarding regional transport, 80% of the total particle pollution was likely to occur under the influence of northerly winds and came from the industrial emissions and human activities in upwind areas. Indeed, there are certain relationships between the planetary boundary layer height, the vertical wind direction and speed, and between the planetary boundary layer height and the number concentrations of different particle size ranges. According to the backward trajectory analysis, the industrial cities in northeastern Chengdu, Chongqing Province, were identified as the major regional sources of particle emissions in winter. Our results provide a scientific basis for the control of particulate matter and ozone in the Shuangliu district, which enables targeted pollution prevention and control measures by the relevant departments.
Seismo-tectonics and magma chambers revealed by the 3D resistivity model in western Yunnan
Authors: Huang Qinghua , Ye Tao , Chen Xiaobin , Zhang Huiqian
Published: March 2024

Based on broadband magnetotelluric (MT) array data, we have obtained the three-dimensional (3-D) electrical resistivity model in western Yunnan, the southeastern Tibetan Plateau where the Quaternary intraplate Tengchong volcanism and seismic activities occur. Our MT model clearly reveals three conductive bodies in the depth ranges of 10–30 km in the Tengchong volcano area, which we interpret as three middle-lower crustal magma chambers associated with the Tengchong volcanism. Seismogenic faults in the Gaoligong Shear Zone (GLGSZ) are characterized by subvertical conductive zones bounded by resistive upper crustal layer on both sides. Earthquakes of moderate magnitudes near the GLGSZ have all occurred within the conductive fault zones at the bottom of the upper resistive crust. Our model also suggests a bifurcation of the crustal flow in western Yunnan, with a southwestern branch running into the Tengchong Block north of the Dayingjiang Fault and a southeastern branch flowing into the Baoshan Block. The current study provides evidence from electrical resistivity structure for the middle-lower crustal magma chambers in the Tengchong volcano area and detailed 3-D electrical structure of crustal channel flow in this active tectonic region.
Aqueous photooxidation of live bacteria 
Authors: Nah Theodora , Liu Yushuo , Lee Patrick
Published: March 2024

Live bacteria in atmospheric aqueous droplets are exposed to photooxidants such as hydroxyl radicals (·OH), organic triplet excited states (3C*) and singlet oxygen (1O2). These photooxidants are produced from photochemical processes involving organic matter present in atmospheric aqueous droplets. ·OH is the photooxidant known to drive many aqueous photochemical processes. Even though the ·OH photooxidation of organic matter in atmospheric aqueous droplets has been widely studied, equivalent investigations on the ·OH photooxidation of bioaerosols are limited. Little is known about the daytime encounters between ·OH and live bacteria in atmospheric aqueous droplets.We investigated the aqueous ·OH photooxidation of four bacterial strains in microcosms composed of artificial cloud water that simulated the chemical composition of cloud water in South China. The survival rates for the four bacteria strains decreased to zero within 6 hours during exposure to 1 × 10−16 M of ·OH under artificial sunlight. Bacterial cell damage and lysis released biological and organic compounds, which were subsequently oxidized by ·OH. We used ultrafiltration to separate the water-soluble biological and organic compounds into different molecular weight fractions and found that the molecular weights of some of these biological and organic compounds were larger than 50 kDa. The biological and organic compounds were identified as proteinaceous-like and humic-like components by excitation emission matrix fluorescence spectroscopy with parallel factor analysis. High-resolution mass spectrometry measurements revealed that the O/C, H/C, and N/C elemental ratios increased at the initial onset of photooxidation. As the photooxidation progressed, there were little changes in the H/C and N/C, whereas the O/C continued to increase for hours after all the bacterial cells have died. The increase in the O/C was due to functionalization and fragmentation reactions, which increased the O content and decreased the C content, respectively. We observed that fragmentation reactions played particularly important roles in transforming the biological and organic compounds. These fragmentation reactions cleaved the C-C bonds of carbon backbones of higher molecular weight proteinaceous-like matter to form a variety of lower molecular weight compounds, including humic-like components of molecular weight
Development of deformational regimes and microstructures in the deep sections and overall layered structures of the Dome Fuji ice core, Antarctica
Authors: Fujita Shuji , Saruya Tomotaka , Miyamoto Atsushi , Goto-Azuma Kumiko , Hirabayashi Motohiro , Hori Akira , Igarashi Makoto , Iizuka Yoshinori , Kameda Takao , Ohno Hiroshi , Shigeyama Wataru , Tsutaki Shun
Published: March 2024

An in-depth examination of rheology within the deep sections of polar ice sheets is essential for enhancing our understanding of glacial flow. In this study, we investigate the crystalline textural properties of the 3035-m-long Antarctic deep ice core, with a particular emphasis on its lowermost 20%. We examine the crystal orientation fabric (COF) and compare it with various other properties from the ice core. In the uppermost approximately 80% thickness zone (UP80%), the clustering strength of single pole COF steadily increased, reaching its possible maximum at the bottom of the UP80%. Below 1800 m in the UP80%, layers with more or fewer dusty impurities exhibit slower or faster growth of cluster strength. This situation continued until 2650 m. In the remaining lowermost approximately 20% thickness zone (LO20%), the trend of the COF clustering strength changed around 2650 m and exhibited substantial fluctuations below this depth. In more impurity-rich layers, stronger clustering is maintained. In impurity-poor layers, relaxation of the COF clustering occurred due to the emergence of new crystal grains with c-axis orientation distinctly offset from the existing cluster, and dynamic recrystallization related to this emergence. The less impure layers show apparent features of bulging and migrating grain boundaries. We argue that the substantial deformational regime of polar ice sheets involves dislocation creep in both UP80% and LO20%, with dynamic recrystallization playing a critical role in the LO20%, particularly in impurity-poor layers, to recover a potential of COF available for the continuation of dislocation-creep-based deformation. Furthermore, we observe that layers and cluster axes of COF rotate meridionally due to rigid-body rotation caused by simple shear strain above subglacial slopes. These features provide vital clues for the development of the 3D structure of polar ice sheets in the deeper part, leading to inhomogeneous deformation between layers in various thickness scales, and the formation of folds, faults and mixing depending on the layers.
Fissure-type vents at 2021 Cumbre Vieja volcanic eruption 
Authors: Sanz-Mangas David , Galindo Inés , Pérez-López Raúl , Rodríguez-Pascua Miguel Ángel , Perucha María Ángeles , Camuñas Carlos , López-Gutierrez Julio , García López-Davalillo Juan Carlos , Lorenzo Carlos , Lozano Gonzalo , Vegas Juana , Marrero Rayco , Hernández Mario , Mediato José Francisco , Sánchez Nieves
Published: March 2024

Multi-vent opening in monogenetic eruptions in the Canary Islands poses a threat considering the fast population increase over the last years. On the 19th of September of 2021 the last volcanic eruption of La Palma Island took place in the Cumbre Vieja volcanic ridge. The lava issued during the eruption affected more than 3000 buildings. The eruption was mainly concentrated along a main fissure that formed a cinder cone of approximately 200 m-high topped by several craters trending NW-SE. Although the geophysical data did not suggest the possibility of new vents opening far from the main fissure, more than 80 low effusion rate vents were opened following NW-SE, N-S and E-W directions. Effusive vents were opened as far as 3 km from the main fissure. Hawaiian style dominated in distal vents, and fast-flow pahoehoe lavas inundated new urban areas apparently out of danger to the south of the lava field. Previous historic eruptions show a similar pattern of several fissure-type vents extending over more than 4 km like Martín in 1642, El Charco in 1712 or San Juan in 1949.In the 2021 eruption some possible precursors were observed previous to the distal vents opening such as CO2 diffuse gas anomalies, the opening of small fractures, local deformation, fumarolic activity and related small landslides before the feeder dike reached the surface. Since distal vents opening was unnoticed by the geophysical monitoring, we propose a detailed monitoring of diffuse gas emission and local fragile and ductile deformation in a radio of several kilometres from the main fissure. The previous knowledge of the detailed volcano-tectonic structure is also essential.
Solar Eruptions Triggered by Flux Emergence Below or Near a Coronal Flux Rope
Authors: Torok Tibor , Linton Mark G. , Leake James E. , Mikic Zoran , Lionello Roberto , Titov Viacheslav S. , Downs Cooper
Published: March 2024

Observations have shown a clear association of filament/prominence eruptions with the emergence of magnetic flux in or near filament channels. Magnetohydrodynamic (MHD) simulations have been employed to systematically study the conditions under which such eruptions occur. These simulations to date have modeled filament channels as two-dimensional (2D) flux ropes or 3D uniformly sheared arcades. Here we present MHD simulations of flux emergence into a more realistic configuration consisting of a bipolar active region containing a line-tied 3D flux rope. We use the coronal flux-rope model of Titov et al. (2014) as the initial condition and drive our simulations by imposing boundary conditions extracted from a flux-emergence simulation by Leake et al. (2013). We identify three mechanisms that determine the evolution of the system: (i) reconnection displacing foot points of field lines overlying the coronal flux rope, (ii) changes of the ambient field due to the intrusion of new flux at the boundary, and (iii) interaction of the (axial) electric currents in the pre-existing and newly emerging flux systems. The relative contributions and effects of these mechanisms depend on the properties of the pre-existing and emerging flux systems. Here we focus on the location and orientation of the emerging flux relative to the coronal flux rope. Varying these parameters, we investigate under which conditions an eruption of the latter is triggered.
High resolution subglacial topography from airborne swath radar beneath the Northeast Greenland Ice Stream (NEGIS)
Authors: Carter Charlotte , Franke Steven , Helm Veit , Jansen Daniela , Hofstede Coen , Paden John , Eisen Olaf
Published: March 2024

Here we present an extensive swath radar dataset collected in the onset region of the Northeast Greenland Ice Stream, surrounding the East Greenland Ice Core Project site (EGRIP). We produce a new digital elevation model (DEM) of the subglacial topography at a resolution of 25 m, covering a study area of 40 km by 60 km. The data was collected using the AWI airborne ultra-wideband radar system, in profiles mainly perpendicular to the ice flow direction with a spacing of 2 km so that the swaths overlapped.The high-resolution subglacial topography DEM shows subglacial landforms beneath an active ice stream, located approximately 600 km into the interior of the ice sheet. These landforms indicate spatially variable bed conditions which are partly reflected in the surface velocity field. Some features appear to be crag and tail formations up to 4 km in length, with steep stoss-side slopes and tapering lee-side tails which are oriented in the direction of ice flow. Megascale glacial lineations up to 7 km in length are evident, but appear restricted to the inner ice stream within the modern shear margins, where the ice flow velocity increases from approximately 11 m/a to 58 m/a. Meltwater channels curve around a high point in the topography, which are on the scale of tunnel valleys formed from subglacial meltwater incision. Seismic data located in a channel at the eastern shear margin indicates soft sedimentation inflow. In summary, differences in landform morphology can be seen within and outside of the ice stream shear margins, indicating that NEGIS ice flow may have been transitory in this region.This survey provides a new insight into the active subglacial environment of a Greenlandic ice stream, matching in quality surveys from ice-free land surface or marine areas. Further analysis will contribute to the understanding of how glacially sculpted landscapes are formed, as well as the effects of small-scale topography on the dynamics and the surface of the overlying ice sheet, in particular ice streams. Moreover, the dataset emphasises the usage of swath radar mapping of bedforms and thus a more widespread application of this method in all radar surveys.
The Iteration Method for Air Density Retrieval in The Stellar Occultation Measurement
Authors: Li Zheng , Wu Xiaocheng , Yang Junfeng , Tu Cui , Hu Xiong , Yan Zhaoai
Published: March 2024

The stellar occultation technique detects Earth’s atmospheric components by measuring the absorption of the stellar spectrum. In this paper, A method of air density retrieval using stellar occultation transmission data in oxygen absorption A band is studied. In this method, the average single-band transmission in oxygen A-band is used to calculate the effective optical depth of each layer of atmosphere by using the peeling onion algorithm. Then, the effective optical depth of each layer and prior atmospheric temperature data are used to obtain the oxygen number density profile by using the retrieval method. Finally, the stable proportion of oxygen in the atmosphere is taken into account. By introducing the iterative algorithm of atmospheric static equilibrium and ideal gas state equation, the accuracy of air density retrieval is improved under the condition of deviation of prior temperature. The results of simulation retrieval are presented in this paper. This method overcomes the negative influence of prior temperature deviation on the retrieval accuracy, and provides a new method and theoretical basis for stellar occultation detection and air density detection.
Fine resolution classification of new ice, young ice, and first-year ice based on feature selection from Gaofen-3 quad-polarization SAR
Authors: Li Haiyan , Yang Kun
Published: March 2024

Sea ice in the high latitude is an indicator of climate change and has undergone dramatic changes because of recent global warming. Synthetic aperture radar (SAR) is a relatively practical tool for sea ice monitoring because of its low sensitivity to clouds, rain, and fog, as well as its capability for high-resolution earth observation in daylight or darkness. With the progression in SAR systems from single-pol to dual-pol, quad-pol and hybrid-pol, large numbers of parameters have been proposed for sea ice classification. Even though a large number of SAR characteristics have been used to classify sea ice, it remains unclear which parameters are the most effective for different regions and seasonal or environmental conditions. Meanwhile, classification studies for fine sea ice with high spatial resolution and many sub-types of sea ice, particularly in the case of rapidly changing first-year ice (FYI), which includes new ice (NI), young ice (YI), and FYI, are rather few. NI and YI have comparatively thinner thickness, and are often classified as FYI in these studies[1].A new method of sea ice classification based on feature selection from Gaofen-3 polarimetric SAR observations is proposed. The new approach classifies sea ice into four categories: open water, NI, YI, and FYI. Seventy parameters that have previously been applied to sea ice studies are re-examined for sea ice classification in the Okhotsk Sea near the melting point on 28 February 2020. The ‘separability index’ is used for the selection of optimal features for sea ice classification. Full polarization (σohh, SEi, Ks) and hybrid polarization parameters (σorl, CPSEi,ρrh-rv, αs) are determined as optimal. The selected parameters are used to classify NI, YI, and FYI using a SVM machine learning classifier; and classification results are validated by manually interpreted ice maps derived from Landsat-8 data. 
[1]Sea ice: types and forms - Canada.ca
Trends of trace gases and aerosol over 2003-2023 at Mount Tai, northern China
Authors: Xue Likun , Wang Tao , Gao Jian , Chen Jianmin , Zhu Yujiao , Wen Liang , Li Hongyong , Sun Lei , Chen Tianshu , Yang Lingxiao , Zhao Yong , Guo Zhaoxin , Wang Wenxing
Published: March 2024

China has been experiencing fast-paced urbanization and industrialization as well as stringent air pollution control in the past decades, which are expected to cause drastic changes in the anthropogenic emissions of primary air pollutants (e.g., SO2, NOx and VOCs). Long-term observations are fundamental to the assessment of response of atmospheric composition to the changing anthropogenic emissions, which are, however, very limited in China. Here we integrated the observational data of trace gases and aerosol obtained during 2003-2023 at Mount Tai – the peak of the North China Plain (1534 m above sea level), a highly polluted region of China. The data were analyzed to understand the long-term changes of a variety of trace gases and aerosol properties such as ozone (O3), PM2.5 composition, particle number and size distribution, new particle formation and growth parameters, and O3 depleting substances (ODS). Surface O3 concentrations showed a significant increasing trend in summertime with a rate of ~2 ppbv yr-1, despite the persistent decrease in NOx emissions since 2012, and can be attributed to the increasing VOCs and O3 production efficiency. Sharp reduction in SO2 emissions have resulted in significant decrease of sulfate in PM2.5, whilst nitrate showed a strong increasing trend. A multi-phase chemical box model illustrated that the reduced SO2 and sulfate enhanced nitrate formation by lessening the aerosol acidity and facilitating the partitioning of HNO3 to the particle phase. The apparent formation rate of new particles in spring has increased at Mt. Tai, while the particle growth rate significantly decreased. The contributions of new particles to the cloud condensation nuclei (CCN) were also decreasing. The ODS regulated by the Montreal Protocol (MP) showed a significant downward trend, but the MP-controlled and unregulated halocarbon species showed overall upward trends. We will also present the results about the impacts of COVID lockdown on the regional air quality as observed at Mt. Tai.
Hominin response to oscillations in climate and local environments during the Mid-Pleistocene Climate Transition in northern China
Authors: Wang Zhe , Zhou Bin , Xu Xiangchun , Pang Yang , Bird Michael , Wang Bin , Meadows Michael , Taylor David
Published: March 2024

Long-term climate trends superimposed on climate variability changes are recognized to manipulate the living environments, and ultimately ecological resources for hominins, which in turn affect hominin activities. Archaeological evidence from loess sediments from Shangchen on the southeastern Chinese Loess Plateau indicates a suspension of hominin occupation around the time of the early mid-Pleistocene climate transition (MPT), prompting a re-assessment of climate-vegetation-hominin interactions. Our research generated magnetic susceptibility, total organic carbon cotent and its carbon isotope compositions, black carbon content and brGDGTs-derived mean annual temperatue and precipitation records in loess deposits with in situ lithic records covering the period of hominin occupation (~2.1–0.6 Ma). The results reveal four distinct climate-vegetation periods (2.1–1.8 Ma, 1.8–1.26 Ma, 1.26–0.9 Ma and 0.9–0.6 Ma). During the early MPT (1.26–0.9 Ma), unprecendently high variability in climate-environment and a long-term aridification with C4 vegetation expansion trend may have driven early humans to move to more hospitable locations in the region. Comparison with the record at Nihewan indicates that large-scale climate oscillations induced disparate hominin responses due to distinctive local environmental conditions.
Effect of chemical composition on zircon radiation damage dating: Implications for low-temperature thermochronology 
Authors: Fan Mingpu , Liu Xiaoming , Sun Shengsi , Dong Yunpeng , Ayers John C. , Santosh M. Warrier
Published: March 2024

Zircon radiation damage dating is a low-temperature thermochronological method that can reveal the cooling history of magmatic intrusions and discriminate sedimentary provenance in combination with other dating methods. This method has broad application prospects because of its advantages of non-destructive, high efficiency, and capable of double (or multiple) dating, involving only multiple measurements by Raman spectrometer and laser ablation-inductively coupled plasma-mass spectrometry. However, several factors, such as zircon chemical composition and the non-uniformity of radiation damage annealing kinetics, can cause poor precision when using this method and thus restricts its wide application. This study examined the effect of chemical composition (P, Ti, Dy, Th, U, and Hf) on Raman spectra using synthetic zircon crystals grown in a lithium-molybdate flux. The results show that the full width at half-maximum (FWHM) of the ν3(SiO4) band has positive linear correlations with the concentrations of P, Ti, Dy, Th, and U in decreasing order of influence, while the FWHM is unaffected by Hf at concentrations <1 wt% but increases at concentrations >10 wt%. Furthermore, the Raman shift is negatively correlated with Th, U, and Dy concentrations, positively correlated with Hf, and shows no obvious correlation with Ti and P. Thus, our study shows that chemical composition is a non-ignorable factor for calculating zircon radiation damage age using Raman spectroscopy, especially for zircon with relatively high concentrations of P, rare earth elements (REEs), Th, U, and Hf. The obtained multiple linear regression equation provides a potential means for estimating the FWHM at zero dose and implication for improving the dating precision of this method. In addition, the observed effects of REEs, Th, U, and Hf on the Raman shift of the ν3(SiO4) band indicate that chemical composition in zircon might affect the estimation of the P-T conditions of geological processes when using entrapped zircon inclusions in host minerals or the field of zircon as an in situ pressure sensor in hydrothermal experiments. Our study suggests that zircon radiation damage dating, excluding geochemical effects, will be more accurate for addressing lower-temperature geological processes.
Sand mining in the Mekong Delta: Extent and compounded impacts
Authors: Park Edward
Published: March 2024

Sand mining has accelerated in recent years primarily due to population increase and rapid urbanization. To meet demand, the rate of sand extraction often exceeds the rate of natural replenishment with serious environmental consequences. In this review paper, the Vietnamese Mekong Delta (VMD), a global hotspot for sand mining with a prolonged history of intensive riverbed extraction, is used as a representative case study to highlight the extent and compounded impacts of this activity. Sand mining budgets from literature present significant discrepancies, with estimates for the entire delta varying from around 8.5 to 42.2 Mm3/yr. These variances can be attributed to the challenges in the actual measurement of mining rates and the deployment of disparate methods across studies. Moreover, the widespread practice of illegal sand mining in the region further exacerbates the mismatch in budget calculations. Consequences of such mining activities manifest as deeply-incised riverbeds leading to riverbank and coastal erosion. Moreover, the massive sediment removal has resulted in river water level reductions, disrupted hydrological connectivity, and diminished floodplain inundation. The augmented backwater effect, a result of riverbed lowering, amplifies saltwater intrusion in dry seasons. While the physical and hydrological impacts have received attention, studies on the ecological and societal ramifications remain sparse. These impacts, further magnified by factors like upstream dams, irrigation infrastructures, excessive groundwater extraction, and sea-level rise (SLR), present a multifaceted challenge. This paper concludes by advocating for the adoption of remote sensing-based approaches for effective mapping of sand mining activities, and implementation of sustainable sand harvesting practices to balance developmental needs with environmental conservation.
Heavy-Precipitating Mid-Tropospheric Cyclonic Systems of the Indian Summer Monsoon in a Warming Climate
Authors: K. Mukherjee Sumit , Dey Choudhury Ayantika , Krishnan Raghavan
Published: March 2024

Since the last couple of decades, western India has been experiencing persistent, intense rain episodes frequently during the summer monsoon season. Most of the pluvial episodes are accompanied by diverse convective systems modulated by the background monsoon circulation. As the climate warms, the changing environmental conditions affect the nature and intensity of the weather systems. This study discusses the evolving large-scale conditions under global warming, along with the recent changes in the occurrence of a special class of heavy-precipitating synoptic systems, the mid-tropospheric cyclones (MTCs). Observed particularly over the Northeast Arabian Sea, MTCs exhibit pronounced mid-level vorticity with minimal signature at the surface. Observational results suggest significant increasing trends in deep convection and heavy precipitation over western India during the summer monsoon season. The background conditions are dominated by warming in the Arabian Sea and the Indian Ocean, accompanied by strengthening of cyclonic circulation and ascending motion at mid-level over western India. An objective vortex identification using reanalysis dataset indicates a rise in the seasonal frequency and duration of heavy precipitating mid-tropospheric cyclonic systems over western India, resulting in a significant amplification of precipitation from these systems. Furthermore, outputs from seven global climate models of the Coupled Model Intercomparison Project Phase 6 (CMIP6) are used to assess the potential changes in the large-scale patterns conducive to the development and sustenance of mid-tropospheric cyclonic systems over western India with continued global warming following the Shared Socioeconomic Pathway 5-8.5 (SSP5-8.5) scenario. The models project stronger moisture transport over western India that triggers greater moisture convergence along the Indian west coast, aided by elevated water vapor content due to local sea surface warming. We also notice an increase in seasonal mean ascent and relative vorticity, particularly, at the middle troposphere, thereby creating a favorable setting for the occurrence of MTCs and the deep convective clouds in the late 21st century. This interplay between circulation–convection–precipitation on different spatiotemporal scales over the South Asian monsoon domain carries significant implications for assessment of regional hydrological extremes in a warming climate.
Understanding Delayed Landslides: A Study of 1,118 Fatal Incidents in China Influenced by Post-Precipitation Runoff
Authors: Wu Kanglin , Simoni Alessandro , Chen Ningsheng
Published: March 2024

The common understanding of landslides points to intense precipitation as a primary trigger. However, this explanation falters when considering landslides occurring with minimal or no rainfall, challenging the basis of empirical and numerical analyses. Taking advantage of a dataset documenting 1,118 landslide disasters with casualties in China since 1984, this study incorporates field investigations, laboratory experiments, and numerical simulations to unravel the mechanisms behind the delayed initiation of landslides influenced by post-precipitation runoff and infiltration. A noteworthy finding emerges: over 75% of catastrophic landslides in China exhibit a temporal delay compared to triggering rainfalls, typically manifesting within one week following peak precipitation. The temporal dynamics of precipitation-induced landslide delays show a range from months to hours, with the delay positively correlated to both landslide scale and the severity of regional drought. Spatially, delayed landslides are frequently related to runoff recharge by upstream catchment, playing a pivotal role in the initiation process. Consideration of topography, climate, and human activities leads to the identification of four typical runoff recharge patterns. We use such patterns to investigate the relationships with the upstream catchment area and delay time, influenced by surface runoff migration and supplied runoff infiltration. Hydrological and slope stability calculations underscore the significance of the catchment area to landslide area ratio while delay time is predominantly governed by surface runoff migration and supplied runoff infiltration into the sliding soil. Results unveil a consistent sequence: robust runoff recharge facilitates water infiltration into weak rock fractures or soil mass, resulting in a gradual increase of pore water pressure. This sequence culminates in the delay of landslide initiation compared to the peak precipitation. These findings may contribute to a scientific foundation for early warning and prediction related to such landslides, thereby mitigating associated risks.
Seismites of the Jurassic Shaximiao Formation in NW Sichuan Basin of SW China: Implication for Dinosaur Taphonomy
Authors: Guo Yao
Published: March 2024

The Sichuan Basin is an expansive Mesozoic-Cenozoic basin in the southwestern mainland of China, with dinosaur fossils widely scattered and full-type accumulated in the Jurassic strata. Wangcang dinosaur fossil burial site is located at the southern foot of the Qinling Mountains and the southern wing of Micang Mountain Uplift in the northern Sichuan Basin. Geologic cross-section measurement, fieldwork, and study of 3D seismic profiles are carried out to explore the mechanism of rapid accumulation and burial of rich incomplete dinosaur fossils in Wangcang. The results show that both the sedimentary process and the tectonic function of the Shaximiao Formation in Wangcang have undergone major changes due to basin and mountain relationships during the sedimentary period. The Shaximiao Formation experienced a transition from the lacustrine sedimentation of the Qianfoya Formation to fluvial-deltaic facies, suggesting climatic and environmental changes. Notably, the Second Member of the Shaximiao Formation coincided with intensified seismic activities, we identified indicators of seismites, including sand pillows, seismic fractures, step faults, liquefied veins, shattering rocks, and seismic breccias, etc. Each set of seismites has different vertical sequences, and the typical liquefied structure deformation directly suggests seismic activities. Tectonically, while the Qianfoya Formation displayed reverse faults, the Shaximiao Formation showed a series of strike-slip normal faults. The seismites and sediment tectonic features reveal a correlation with the catastrophic mass mortality of dinosaurs in Wangcang. We propose that seismic events significantly impacted dinosaur habitats, leading to mass deaths and subsequent burials in the purplish-red argillaceous siltstone near Huaishu Village in Wangcang. For the first time, the seismites are presented as new evidence of tectonic shifts and seismic activities in Wangcang during the Middle Jurassic, and it provides a new perspective for dinosaur taphonomy in the Sichuan Basin.
Drought propagation from meteorological to hydrological drought in the Krishna River Basin of India
Authors: Gupta Ajay , Jain Manoj Kumar , Pandey Rajendra Prasad
Published: March 2024

Understanding the propagation of drought from one form to another has become a prime topic of research during recent decades. The majority of research has used a correlation-based approach to study drought propagation; however, such techniques are ineffective in areas with considerable seasonality in precipitation, such as India. Only a few studies have employed an event-based approach to study drought propagation. Moreover, none of the previous studies considered the sequential propagation of drought, starting from meteorological to hydrological drought through agricultural drought. This work aims to analyse drought propagation from meteorological to hydrological drought through agricultural drought using an event-based approach in the Krishna River Basin of India. The Standardised Precipitation Evapotranspiration Index (SPEI) represents meteorological drought, the Standardised Soil Moisture Index (SSMI) represents agricultural drought, and the Standardized Streamflow Index (SSI) represents hydrological drought is estimated at a 1-month timescale at sub-basin scale. The precipitation and temperature data are procured from the India Meteorological Department (IMD) Pune, the soil moisture data is obtained from the European Space Agency (ESA) Climate Change Initiative (CCI) v03.3, and the streamflow data is downloaded from India-WRIS. Two different cases of drought propagation are analysed: meteorological to agricultural drought (SPEI-SSMI) and agricultural to hydrological drought (SSMI-SSI). Propagation of drought is quantified through the estimation of three-time matrices: (1) the time difference between the initiation of droughts, (2) the time difference between the peak of droughts, and (3) the time difference between the termination of droughts. The results from the study revealed that the SSMI drought was initiated after 6.4 months of the SPEI drought, while the SSI drought was initiated after 8.4 months of the SSMI drought. The peak of SSMI drought is found to be after 6.3 months of the peak of SPEI drought, while the peak of SSI drought is found to be after 34.7 months of the peak of SSMI drought. Once the SPEI drought terminates, it lasts for 8.3 months for the SSMI drought to terminate, while after the SSMI drought terminates, it lasts for 30.7 months for the SSI drought to terminate. Thus, it was found that the propagation of drought from SPEI-SSMI is faster than the propagation of drought from SSMI-SSI. The present work will provide essential information on drought propagation, which will be helpful in the management and mitigation of droughts in India. Keywords: Drought Propagation, Propagation Time, SPEI, SSMI, SSI.
Semi-Autonomous Robot Support for A Mars Analog Exploration Cascade
Authors: Steinbauer-Wagner Gerald , Jusner Simon , Eder Matthias , Moser Stefan , Halatschek Richard , Didari Hamid , Schaffler-Glößl Sebastian , Lebschy Alexander
Published: March 2024

In this article we present a semi-autonomous robotics framework developed to support the exploration cascade within the Mars analog simulation AMADEE 2024. The exploration cascade defines the process of refining the situation awareness during the scientific exploration of parts of a planet like Mars. Starting from remote sensing using orbiters over the use of UAVs down to in situ investigations using rovers or astronauts the understanding of an area or phenomena is improved. In particular the final step of inspecting, taking measurements, and collecting samples at the point of interest is of importance and the direct involvement of a human is a plus as the human is able to immediately provide a comprehensive intuitive interpretation. Because EVAs pose a risk and are demanding, having a remote inspection tool like a rover to eliminate less interesting or promising areas is of interest. Thus, we developed a semi-autonomous robot system able to travers challenging Mars-like terrain and to collect data such as images, 3D models, and spectroscopy measurements. The astronaut and the rover work as a team where the astronaut defines inspection goals and may take over if the rover gets into a unwanted or dangerous while most of the time the rover acts autonomously. The rover is integrated into a mission software architecture which stores all relevant information (e.g. missions, trajectories, goals, data) in a common GIS system in order to support the task execution by the astronaut but also the mission planning by the flight plan team as well as the interpretation of the data by the science team. We will discuss our design decisions derived from interaction with mission experts and will present preliminary results from a field deployment during the AMADEE 2024 Mars analog simulation.
Mechanisms controlling storage capacity dynamics in China’s largest freshwater lake
Authors: Hu Yong , Li Dongfeng , Deng Jinyun , Li Yitian , An Zhisheng
Published: March 2024

Poyang Lake is the largest freshwater lake in China, yet mechanisms controlling its storage capacity variations remain poorly investigated. Here we show that lake storage capacity dynamics are mainly driven by jacking force and outlet channel erosion, based on 39-year daily in situ observations (1980-2018). A lower water level at the lake outlet and a diminished jacking force in the Yangtze River can be attributed to the upstream dams storing water between August and October; consequently, more water from Poyang Lake flows out, causing the impairment of storage capacity. Furthermore, channel degradation near the outlet is likely due to the severe sand mining and hungry-water-driven Yangtze channel erosion, the latter of which implies an enhanced outlet channel scour. As a result, the lake storage capacity has been substantially weakened. Our findings further the understanding of the downstream lake storage capacity responses to dam operation and human activities and have important implications for lake ecology and flood management in large dammed river-lake systems.
Equatorially trapped waves in a stratified region in the Earth’s outer core modeled using 2-layer shallow water equations
Authors: Sharma Dheeraj Kumar , Sahoo Swarandeep
Published: March 2024

Near the equatorial region of the Earth’s core, secular variation in the geomagnetic field consists of short period fluctuations. Such fluctuations in the magnetic field are believed to be the result of equatorially trapped waves close to the core-mantle boundary. The balance between the magnetic, Coriolis and buoyancy forces can sustain waves if a stably stratified layer exists in the outermost regions of the core. In this study, a shallow water model with additional magnetic field effects has been used to investigate the characteristics of such equatorially trapped waves. A two-layer model is studied analytically to investigate the effects of radially varying background magnetic fields on the equatorially confined MAC waves. Dispersion relations obtained are significantly influenced by the dependency of the second layer pressure gradient on that of the first layer.  Moreover, the reduced gravity effects in the second layer also modifies the second layer dynamics. Additional parameters, formulated in terms of density, magnetic field strength and buoyancy frequency of both layers characterize the system. The modified properties of a two layer model compared to a single layer is investigated for various regimes of such control parameters. It is found that the alteration in the second layer’s buoyancy frequency significantly influences the dynamics of the MAC (Magnetic-Archimedes-Gravity) wave.
HRGEN: A stochastic generator of hourly rainfall
Authors: Wang Wenting , Yin Shuiqing , Yu Bofu
Published: March 2024

Rainfall data are needed as input to drive hydrological and soil erosion models. Daily rainfall data are commonly used and widely accessible, whether sourced from meteorological observations or simulated by Global Climate Models (GCMs). However, daily data cannot capture intensity variations during a storm event, and may not be sufficient to capture the changes during extreme weather events under climate change scenarios. Weather generators (WGs) are statistical models that can generate random sequences of meteorological variables that exhibit statistical characteristics that are similar to observations. However, the low accuracy of generated sub-daily rainfall intensities motivated this study to stochastically disaggregate daily precipitation total at hourly intervals so that observed or GCM generated daily rainfall can be downscaled into hourly scale stochastically. To achieve this, we developed a model, HRGEN, based on long-term hourly precipitation data from 1971 to 2020 from 2405 meteorological stations across mainland China. The major improvement of this model over CLIGEN includes: (1) HRGEN significantly enhances the simulation accuracy of maximum peak intensities on an hourly basis (Hmax). The average Hmax over 2405 stations of hourly observations and HRGEN-generated are 4.0 mm h-1 and 4.2 mm h-1, respectively, while that generated by CLImate GENerator (CLIGEN) is 6.5 mm h-1. The mean absolute relative error (MARE) over 2405 stations is 8.2%. This improvement is critical for accurately estimating daily EI30 values, a key index in soil erosion models and soil loss prediction; (2) HRGEN preserves the relationship between total daily precipitation and storm duration and peak intensity; (3) The model has only six parameters, markedly simplifying the calibration and simulation processes. The HRGEN-simulated hourly rainfall data can be used to estimate rainfall erosivity for erosion prediction. The R-factor estimated using HRGEN-generated hourly data agrees well with the observed R-factor values, with a high Nash-Sutcliffe efficiency coefficient (NSE) of 0.92. The average R-factor estimated from hourly observations and HRGEN-generated hourly observations over 2405 stations are 3699.2 and 3720.7 MJ mm ha-1 h-1 a-1, respectively. In comparison, R-factor estimated by CLIGEN-generated rainfall is 9100.7 MJ mm ha-1 h-1 a-1. This study highlights HRGEN’s potential as a robust tool for stochastic generation of sub-daily rainfall as input to hydrologic and soil erosion models.
Data inheritance concept in mineralogical warehouse
Authors: Gavryliv Liubomyr , Ponomar Vitalii , Putiš Marián
Published: March 2024

Recently, there has been a substantial surge in the availability of web services offering access to geological, geochemical, crystallographic, and mineralogical data. Embracing this data-rich environment, mineralogy.rocks emerges as a pioneering outreach project, poised to harness the vast potential embedded in this information reservoir. Focused on extracting valuable insights, the project seeks to leverage the wealth of open-access data and fosters knowledge dissemination by openly sharing the underlying code of its processes under MIT, available on https://github.com/orgs/mineralogy-rocks. Mineralogy.rocks' core developers recently tackled the challenge of establishing relationships between minerals and their associated entities such as synonyms, varieties, and parental groups. Often, these related entries lack distinct properties; synonyms may only have a name and historical context, chemical varieties might differ only in impurity presence, and structural variations may diverge solely in crystal system. Database-wise, all other properties remain identical to the parent mineral. In response, we introduce the concept of Data Inheritance, drawing parallels with Object-Oriented Programming's class inheritance mechanism. This concept permits multiple base classes, enabling a derived class to override methods of its base class or classes, thus allowing objects to encompass diverse and arbitrary data. Applied to a data warehouse dimension, this concept facilitates the retrieval of the actual properties of a related entry defined in the database and the inherited properties not defined for this specific entry but established for the parental mineral. To implement this, we calculate the inheritance chain, representing the chain of relations from the bottom-most child entry to the top-most parental mineral, such as in the case of agate—chalcedony—quartz. The chain, coupled with specific code rules and patterns, enables the retrieval of properties for each entry in the chain, effectively determining which properties are pertinent to the child species. This systematic approach adds precision and clarity to the extraction and utilization of mineralogical data in the context of inherited properties.mineralogy.rocks is dedicated to open science, prioritizing innovation, quality, and public impact in mineralogical research. Our commitment is evident through actions that swiftly share research outcomes and metadata, fostering accessibility and reuse. Embracing open science principles, we contribute to advancing the field with transparent and collaborative practices.This project, No. 3007/01/01, has received funding from the European Union’s Horizon 2020 research and innovation Programme based on a grant agreement under the Marie Skłodowska-Curie scheme No. 945478 and was supported by the Slovak Research and Development Agency (contracts APVV-19-0065 and APVV-22-0092).