bluuebunny/crossref_metadata_2025 huggingface dataset:
Effective Characterization of Fractured Media with A Novel Deep Learning-Based Data Assimilation Approach
Authors: Nan Tongchao , Zhang Jiangjiang , Xie Yifan , Lu Chunhui
Published: March 2024

In various research fields such as hydrogeology, environmental science and energy engineering, geological formations with fractures are frequently encountered. Accurately characterizing these fractured media is of paramount importance when it comes to tasks that demand precise predictions of liquid flow and the transport of solutes and energy within them. Since directly measuring fractured media poses inherent challenges, data assimilation (DA) techniques are typically employed to derive inverse estimates of media properties using observed state variables like hydraulic head, concentration, and temperature. Nonetheless, the considerable difficulties arising from the strong heterogeneity and non-Gaussian nature of fractured media have diminished the effectiveness of existing DA methods. In this study, we formulate a novel DA approach known as PEDL (Parameter Estimator with Deep Learning) that harnesses the capabilities of DL to capture non-linear relationships and extract non-Gaussian features. To evaluate PEDL’s performance, we conduct two numerical case studies of increasing complexity. Our results unequivocally demonstrate that PEDL outperforms three popular DA methods: Ensemble Smoother with Multiple Data Assimilation (ES-MDA), Iterative Local Updating Ensemble Smoother (ILUES), and ES with DL-based Update (ES-DL). Sensitivity analysis confirms PEDL’s validity and adaptability across various ensemble sizes and DL model architectures. Furthermore, even in scenarios where a mismatch exists between the reference model and the forecast model’s structure, PEDL adeptly identifies the primary characteristics of actual fractures.
Enabling Reliable Workflow Development with an Advanced Testing Suite
Authors: Ahmed Rohan , Bonet Garcia Genis , Montane Pinto Gilbert , Ferrer Escuin Eric
Published: March 2024

Typically climate simulations have a complex workflow and involve the integration of multiple components along with different sets of configuration for scientific experiments which usually involves HPC resources. In order to ensure the reliability and reproducibility of a complex workflow code base, there is always the need for Continuous Integration tests that help validate the final product. Additionally, these  integration tests also help in streamlining major and minor releases for a more efficient development lifecycle. However, the exhaustive testing of such numerous integration tests is a laborious and time-consuming process. It poses significant challenges and costs in terms of time and resources. To address these challenges in the domain of the climate scientist community, we introduce our Testing Suite software. It provides a mechanism to  set up, configure and run integration tests in an automated way leveraging the powerful resources of HPC.The Testing Suite plays a pivotal role in quality assurance, particularly during major releases where longer tests are conducted to validate the entire product thoroughly. The integration tests serve as a litmus test for major releases, ensuring that the final product meets the required standards and functionality across various configurations. In the context of minor releases, the testing suite takes on an equally crucial role. Here, these tests act as checkpoints, delineating stable points in the main codebase from which developers can confidently create development branches. This approach ensures that these branches are derived from a stable foundation, reducing the likelihood of compatibility issues and enabling a smoother development process.Moreover, the suite automatically checks outputs of scientific results, compares them bit by bit and thereby swiftly detecting regressions during test execution.. Additionally, the suite also provides valuable insights in terms of performance metrics by evaluating scientific results automatically.  In conclusion, the suite becomes an integral part of the workflow development lifecycle, safeguarding against potential pitfalls and fostering a culture of innovation built on a solid foundation of stability and functionality.
Coupling between thermospheric gravity waves and non-migrating tides simulated by the Whole Atmosphere Model
Authors: Malhotra Garima , Fuller-Rowell Timothy , Heale Christopher J. , Fang Tzu-Wei , Yudin Valery , Karol Svetlana , Kubaryk Adam Marshall
Published: March 2024

The signatures of gravity waves (GWs) are often observed at ionospheric and thermospheric (IT) heights in satellite and ground-based observations. They play an important role in coupling different regions of the Earth’s atmosphere, as they transport energy and momentum and are often observed during both geomagnetically quiet and active times. GWs at IT heights can either be of meteorological origin propagating up from the lower atmosphere, or excited in-situ. They can also non-linearly interact with tides and planetary waves adding to the dynamic variability of the thermosphere. In this study, we aim to investigate the coupling between non-migrating thermospheric tides and GWs during geomagnetically quiet times using the high-resolution whole atmosphere model (WAMT254) and satellite observations. We find that when observed at a constant local time in the lower and upper thermosphere, a wavenumber-4 longitudinal signature is present in the GW activity at low-latitudes. This signature moves eastward with local time and is more prominent during September between ~6-12 LT. Diagnostics of the background zonal winds indicate a modulation of GWs by wave-4 signal of non-migrating tides. We provide the first evidence of this modulation and discuss the coupling mechanisms using the Model for Acoustic and Gravity wave Interactions and Coupling (MAGIC). We also show that similar inferences can be made from ICON satellite observations within reasonable uncertainty.
Evaluating the Effect of Toe Erosion on Slope Stability through the Integration of Hydraulic Model and Slope Stabilization
Authors: Liang Chun Wei , Chan Hsun Chuan
Published: March 2024

When heavy rainfall occurs in mountainous areas, the water level in streams rises, and the flow velocity increases, result in the enhancement of erosive capacity. As the fast-flowing water approaches the riverbanks, the stability of the riverbank slopes may reduce due to toe scour. It may further lead to the occurrence of near-bank landslides. The deposition of soil and sediment in the riverbed caused by landslides can have a major impact on the safety of the nearby residents and communities.
The Erwanping landslide area in the upstream Ali Mountain watershed, Taiwan was selected as the research area. By the means of the CCHE-2D hydraulic model, flood simulations with return periods of 10, 25, 50, and 100 years were conducted in the river near the landslide areas. The scour of the riverbanks was analyzed. Subsequently, a slope stability model was established based on the post-flood bed elevation predicted by the CCHE-2D. The impact of toe scour of slopes on slope stability was evaluated through the changes of safety factor subjecting to floods of various return periods. The present approaches provide important information for development of disaster prevention and warning system in the riverbank areas.
 
Keywords: Riverbank, Landslide, Hydraulic model, Slope stability
Snow cover and snow water equivalent dynamics in the Upper Indus Basin (UIB) under current and CMIP6 climatic projections
Authors: Nazeer* Aftab , Asif Muhammad , Inam Azhar , Asif Muhammad
Published: March 2024

Snow is an integral part of the climatic system, hydrological cycle and a significant moisture source. Among the basins in the high mountains of Asia, the Upper Indus Basin (UIB) generates snow and glacier melt contribution (70 % of the total river flow), the second highest after the Brahmaputra and Ganges. The climate is changing and its adverse impacts may have severe implications for melt-dependent river basins like the Indus. Therefore, simulating realistic snow cover and snow water equivalent dynamics is essential for understanding the hydrological processes and water resource management under current and future scenarios. This research aimed to analyse snow cover area (SCA) and snow water equivalent (SWE) dynamics for the Hunza basin (subbasin of the Indus) under current and future climatic conditions. A data-parsimonious precipitation-runoff model, Distance Distribution Dynamics (DDD), with its energy balance sub-routines for melt simulations, was forced with newly developed ERA5-Land (0.1°x0.1°) gridded datasets. The climatic projections derived from the Coupled Model Intercomparison Project Phase 6 (CMIP6) based general circulation models (GCMs) were used for future scenarios until the end of the 21st century. The model simulates SCA between 99 % of the study area (in January) and 10 % (in August) and SWE between 270–320 mm (in February) and 10–15 mm (also in August). The simulated SCA was validated using MODIS-driven SCA, and the results are promising. The Hunza River’s flow gets its maximum contribution from glacier melt (45–48 %), followed by snowmelt (30–34 %) and rainfall (21–23 %). Results also reveal that future SCA decreases significantly in all warming scenarios relative to the baseline scenario. Moreover, significant changes are expected in precipitation cycles and their timings, with increased liquid precipitation (rainfall) for the 21st century. These changes can significantly alter the downstream water availability, agricultural cropping patterns, and extreme flow conditions for snow melt-dependent regions like the Indus. The findings from the current study may provide helpful information about the snow and glacier melt contributions to future hydrological regimes.
 
Key Words: CMIP6, Energy Balance (EB), ERA5-Land, Hunza River basin, SCA, SWE, Upper Indus Basin (UIB)
Frictional properties of the fault hosting aftershocks of the 2014 Orkney earthquake (M5.5), South Africa, and proposal of a new drilling project PROTEA to probe the heart of the earthquake
Authors: Yabe Yasuo , Ogasawara Hiroshi , Durrheim Raymond
Published: March 2024

 The ICDP-DSeis (Drilling into Seismogenic zones of M2.0 – M5.5 earthquakes in deep South African gold mines) project recovered rock samples from a fracture zone that hosted the aftershocks of the 2014 Orkney earthquake (M5.5). The fracture zone was formed in an altered lamprophyre dike (Lamprophyre, hereafter) intruded into the Crown Formation (local name of altered basaltic andesite). One of the DSeis holes intersected another dike (named the Onstott dike) ~300 m east of the Lamprophyre. A fissure containing ancient (1.2 Ga) hypersaline brine rich in DOC (dissolved organic carbon) was found in the Onstott dike. The formation and metamorphism of these dikes are discussed in Ogasawara et al. (EGU24). This study describes the frictional properties of Lamprophyre that motivated us to propose a new drilling project PROTEA.The southern shallowest section of the fault intersected by the DSeis hole did not slip significantly during the Orkney earthquake mainshock, but hosted high aftershock activity. This implies that the fault intersected by the DSeis hole was stable frictionally and decelerated coseismic slip to halt the dynamic propagation of the mainshock rupture. Thereafter, the fault transitioned to an unstable state and produced aftershocks. The recovered rocks revealed the Lamprophyre did not contain any quartz and was rich in talc, biotite, amphibole, and calcite. Loss of drilling water into the fault zone suggested that the pore pressure in the fault zone was low (
Assessment of Landslide Susceptibility under Climate Change in the Laonong river watershed in Taiwan
Authors: Wu Chunhung
Published: March 2024

The study focuses on the distribution of landslide susceptibility in the future under climate change in the Laonong river watershed (abbreviated as LRW) in southwestern Taiwan. LRW is a mountainous watershed prone to sediment disaster and had caused serious sediment disaster during 2009 Typhoon Morakot. The study used the downscaled daily rainfall data provided by Taiwan Climate Change Estimation Information and Adaptation Knowledge Platform (TCCIP) as the daily rainfall data in the future in LRW. We combined the daily rainfall data and the landslide susceptibility model in the LRW to assess the distribution of landslide susceptibility in the future in the LRW.The landslide susceptibility model was composed of 9 landslide-related factors, including elevation, slope, aspect, geological setting, landuse, Topographic Wetness Index, distance from the rivers, landslide frequency, and daily rainfall. This study built the landslide susceptibility model of LRW based on the daily rainfall data and landslide inventory after 2009 Typhoon Morakot. The AUC (area under receiver operating characteristic curve) of the landslide susceptibility model is 0.712, and the accuracy by using the confusion martix is 0.731.The study also compared the rainfall characteristic in the past (the rainfall data from 1998 to 2022) and the future (the downscaled rainfall data from 2023 to 2100) in the LRW. No significant difference shows between the characteristic of average annual rainfall in the past and the future, but the monthly rainfall is obviously concentrated in the rainy season, i.e. from May to October. The occupied percentage of accumulated rainfall in the rainy seasons to annual rainfall in the future is larger by 0.3% to 4.1% than that in the past. The daily rainfall with 50 years return period in the future is larger by 56% to 125% than that in the past.The study combined the daily rainfall data in the future under climate change scenarios SSP126 and SSP585 and the landslide susceptibility model based on 2009 Typhoon Morakot to assess the distribution of landslide susceptibility in the LRW in the future. The area of middle-high and high landslide susceptibility in the LRW increased obviously based on the distribution of landslide susceptibility in the future under climate change. The average landslide susceptibility value in the future in the LRW is larger by 1.7 times than that in the past.
The mountains are falling and I must go: paraglacial landslide response to glacier debuttressing in southern Alaska
Authors: Walden Jane , Jacquemart Mylène , Higman Bretwood , Hugonnet Romain , Manconi Andrea , Farinotti Daniel
Published: March 2024

Glacier mass loss due to anthropogenic climate change has far-reaching implications, one of which is the destabilization of paraglacial slopes. The buttressing force, or the support provided by the glacier to adjacent valley walls, changes and eventually decreases to zero as glaciers dwindle. However, the processes governing this (de-)buttressing, the amount of support glaciers can provide, and to what extent glacier retreat is responsible for landslide (re-)mobilization are still poorly understood. Paraglacial landslides can be hazardous, especially in the proximity of deep water, where a catastrophic failure has the potential to produce a tsunami.We investigated eight large (roughly 20 to 500 million m3) paraglacial landslides in southern Alaska, a region which is experiencing some of the fastest glacier retreat worldwide. The selected landslides have varying degrees of ice contact: some are still experiencing active glacier retreat and thinning, others have already lost contact with the glacier. One of the selected landslides has undergone catastrophic failure, the others have not. We reconstructed the deformation history of the eight sites using Landsat images from the 1980s to present and automated and manual feature tracking. The slope evolution was then compared to ice thinning rates, ice velocity changes, the proximity of the landslide to the glacier terminus, environmental conditions, and seismic energy. We found that both thinning and retreat are sufficient conditions for landslide (re-)activation. In two cases we documented periods of acceleration for slopes where ice is still present at the landslide toe but thinning rapidly. In two further cases, substantial thinning did not correspond to any detectable motion. In four cases we observed a rapid retreat of the glacier terminus as the glacier retreated progressively up-fjord which led to the sudden onset of slope motion. This acceleration suggests decreased stability, which may be important in close proximity to water-filled basins, where rapid retreat due to calving is common and catastrophic landslides can cause tsunamis if they impact the water. The association of reduced glacier-slope contact, especially at rapidly retreating termini, with accelerated slope deformation suggests that buttressing is indeed an important stabilizer for paraglacial slopes. Furthermore, the off-and-on nature of deformation suggests there are critical thresholds for buttressing that, when crossed, leave slopes prone to rapid change.
Challenges in Assessing and Managing Multi-Hazard Risks: A European Stakeholders' Perspective
Authors: Sakic Trogrlic Robert , Reiter Karina , Ciurean Roxana , Gottardo Stefania , Torresan Silvia , Daloz Anne Sophie , Ma Lin , Padron-Fumero Noemi , Tatman Sharon , Ward Philip ,   MYRIAD-EU Team
Published: March 2024

Recent findings indicate an increasing frequency of multiple hazards and their interrelationships (such as triggering, compound, and consecutive events) across Europe, highlighting the urgency for resilience enhancement. This shift demands a transition from focusing solely on single-hazard risks to embracing multi-hazard risk assessment and management strategies. Despite substantial progress in understanding these complex events, the predominant approach still concentrates on individual hazards (like floods, earthquakes, droughts), with a relatively narrow grasp of the actual needs of stakeholders on-site. Addressing this gap, our study aims to explore the challenges of shifting towards multi-hazard risk management from the viewpoint of European stakeholders. Through five workshops conducted in various European locations (Danube Region, Veneto Region, Scandinavia, North Sea, and Canary Islands) and a specialized expert workshop, we pinpoint five key challenges: governance issues, understanding of multi-hazards and multi-risks, current disaster risk management practices, bridging scientific knowledge to policy and practice, and the lack of data. These challenges are interdependent and must be approached comprehensively, as the legacy of existing practices presents a significant obstacle in moving from single-hazard to multi-hazard risk management. Looking ahead, we identify several promising strategies to address some of these challenges, including novel methods for multi-hazard characterization, a unified terminology, and an all-encompassing framework to guide multi-hazard risk assessment and management. We advocate the necessity to broaden our perspective beyond natural hazards, incorporating other types of threats for a more complete multi-hazard risk understanding, and to integrate multi-hazard risk reduction within broader developmental objectives.
Impact of future Greenland ice sheet melt on the stability of the Atlantic Meridional Overturning Circulation
Authors: Pöppelmeier Frerk , Stocker Thomas F.
Published: March 2024

The Atlantic Meridional Overturning Circulation (AMOC) is projected to weaken due to the increase in buoyancy caused by anthropogenic warming and consequent freshening during the 21st century and beyond. Atmosphere-ocean general circulation models simulate this AMOC weakening due to warming of the surface ocean, changes in the hydrological cycle that shift the North Atlantic salt budget, melting sea-ice, and changes in the atmospheric circulation. However, the freshwater contribution from the melting Greenland ice sheet is often either only considered in idealized scenarios or entirely omitted due to computational constraints. This simplification contributes to the large uncertainty surrounding the possibility of the AMOC crossing a tipping point in the forthcoming centuries. Here we employ the fully coupled Earth system model of intermediate complexity Bern3D v3, which dynamically simulates all ice-ocean-atmosphere interactions. We conduct a set of simulations driven by idealized CO2 concentration paths to investigate the impact of the melting Greenland ice sheet on the stability of the AMOC over the next 3000 years. We find that for a slow CO2 increase of 0.5%/yr up to twice pre-industrial levels, the general trends of the AMOC evolution are independent of whether Greenland meltwater is taken into account, with an initial weakening, but long-term recovery. Yet, the additional meltwater results in a further weakening of about 3 Sv after 100 years, but without leading to a full collapse of the circulation. This effect is due to melt rates remaining relatively low for the initial 100 years and only reaching their peak after 500 years. In the long-term, the curtailed AMOC and hence northward heat transport substantially slows down the disintegration of the Greenland ice sheet. Only in scenarios where the melt rates are kept artificially high, the AMOC does not recover. This highlights that the meltwater-induced AMOC weakening stabilizes the Greenland ice sheet, which in turn limits further AMOC weakening. This suggests that the potential for cascading interactions may be limited.
Exploring the physical consistency of evapotranspiration estimates over Madagascar using remote sensing.
Authors: alimohammad nejad rojin , D. Carrière Simon , Olioso Albert , Oudin Ludovic
Published: March 2024

Evapotranspiration (ET) plays a major role in climate processes by facilitating water redistribution between continental surfaces and the atmosphere. Accurately quantifying ET remains a challenge due to the scarcity of direct ET measurements, particularly in some regions with poor climate monitoring like Madagascar. Moreover the island has a very different climate, from semi-arid in the southwest to humid in the east. Estimating ET from remote sensing and climate reanalysis appears as a relevant way to provide spatially distributed data at a regional scale. Several operational or pre-operational usually, they providing quite different results. How to choose the most relevant product for a study area is a key question for any hydrological study.Our study focused on evaluating five popular evapotranspiration products over Madagascar: GLDAS-NOAH, ERA5, ERA5-LAND, WAPOR, and GLEAM. The data covers years from 2009 to 2021. The analysis aims to provide a comprehensive understanding of their utility and accuracy in estimating ET over the different climatic zone.Our initial findings involved a comprehensive assessment of various datasets, focusing on their differences and evaluating their validity in maintaining water and energy balance. This comprehensive analysis encompassed (i) analyzing jointly evapotranspiration estimates, potential evapotranspiration, and precipitation used by each ET dataset and (ii) validating ET estimates on the few catchments where streamflow data are available. The results indicate significant differences in ET estimates, as well as in each climate zone in Madagascar (in average 550 mm/year in semi-arid area and 1050 mm/year in humid area). The observed differences warrant a deeper exploration of the factors contributing to these differences and a careful assessment of the strengths and limitations of each datasets.
Modelling the formation of an extreme Australian pyro-convection event and its sensitivities
Authors: Müller Jason , Senf Fabian , Tegen Ina
Published: March 2024

During the Australian fire season 2019/2020, an unprecedented amount of smoke aerosol was not only released, but also transported upwards and injected into the tropopause region by so-called pyro-cumulonimbus clouds (pyroCb). The resulting lower stratospheric aerosol loads in early 2020 were comparable to those of the largest volcanic eruptions of the twentieth century. PyroCbs have been identified as the main pathway for biomass burning aerosol into the stratosphere. To study the phenomenon of PyroCbs, simulations of the so-called Australian New Year Super Outbreak are performed with the numerical weather model ICON. Simulations were run in a nested, limited area mode setup, with the smallest domain reaching down to a horizontal grid spacing of 500 m. Within the domain, an idealised fire perturbation was applied for which an additional constant surface sensible heat and water vapour flux was introduced to represent the thermodynamical impacts of the fire. Simulations with this setup were successful in producing fire-induced deep convection with subsequent smoke injection into the lower stratosphere. Preliminary sensitivity experiments show a high sensitivity of the PyroCb properties to initial and boundary conditions. We can show, that especially water vapour emissions, which would originate from evaporating surface water as well as from combustion of organic materials, have a decisive, enhancing impact on the pyro-convection. Moreover, besides the fire intensity, the plume characteristics and smoke injection heights are also closely linked to the background meteorology, in particular. In the long term, the goal is to incorporate the effects of extreme biomass burning emission into large scale climate simulations by taking into account PyroCb activity. However, this will require a very deep understanding of wildfire triggered convection and PyroCb dynamics.  
Establishing management zones for irrigation using soil properties and Remote Sensing
Authors: Ksantini Faten , Tarquis Ana M. , Almeida-Ñauñay Andrés , Sanz Ernesto , Quemada Miguel
Published: March 2024

Soil texture influences many other soil attributes, including its physical, chemical, and biological characteristics. Soil texture dictates vital factors such as aeration, nutrient, water availability, and heat retention. These aspects collectively impact various aspects of plant life, encompassing growth, development, productivity, and quality. Agricultural soils are commonly classified into several categories based on their texture to facilitate effective agricultural practices like tillage, irrigation, fertilization, and pesticide applications.A growing call has recently been made for integrating machine learning (ML) techniques to enhance comprehension and insight into soil behaviour. However, it is essential to note that real-world datasets often exhibit inherent imbalances. In such cases, ML models tend to overemphasize the majority classes while simultaneously underestimating the minority ones. This study aimed to investigate the effects of imbalance in training data on the performance of a random forest model (RF).The original data used in this work was from La Chimenea farm station near Aranjuez (Madrid, Spain). The variables included were Electrical conductivity (EC), EC shape, EC depth, EC ratio, slope, curve, and NDVI derived from Sentinel-2. Clay and sand percentages were obtained with the exact spatial resolution, and the USDA classification was applied based on them. A descriptive statistics analysis was conducted to analyze the data. Then, Pearson's coefficient (r) of linear correlation was calculated to verify possible relations between the different variables. Then, a synthetic resampling approach using the Synthetic Minority Oversampling TEchnique (SMOTE) was employed to make a balanced dataset from the original data.The imbalance and balance data classification were compared to see SMOTE's benefits in better-classifying soil texture.Keywords: digital soil mapping; machine learning; soil texture; imbalance classification; data resampling  AcknowledgementsThis work has received support from projects PID2021-124041OB-C22 and PID2021-122711NB-C21, funded by the Ministerio de Ciencia e Innovación (Ministry of Science and Innovation). 
Initial-Value vs. Model-Induced Forecast Errors: A New Perspective
Authors: Toth Zoltan , Jankov Isidora
Published: March 2024

Numerical models of the atmosphere are based on the best theory available. Understandably, the theoretical assessment of errors produced by such models is confounding. Without clear theoretical guidance, the experimental separation of the model-induced part of the total forecast error variance is also challenging. In this study, forecast error and ensemble perturbation variances are decomposed. Independent smaller- and larger-scale components separated as a function of lead time are found to be associated with features that completely or only partially lost skill, respectively. For their phenomenological description, the larger-scale variance is further decomposed orthogonally into positional and structural components. An analysis of the various components reveals that chaotically amplifying initial perturbation and error variance predominantly leads to positional differences in forecasts, while structural differences are interpreted as an indicator of model-induced error. The relatively small amplitude of model-induced errors confirms earlier assumptions and limited empirical evidence that numerical models of the atmosphere may be near perfect on the scales they well resolve.
 
Exploring the influence of sediment cover on bedrock channel slope and width responses to climate and tectonic perturbations 
Authors: Guryan Grace , Tucker Gregory , Johnson Joel
Published: March 2024

Sediment plays a key role in modulating bedrock channel response to tectonics and climate. By armoring the channel bed, sediment cover can dampen the topographic expressions of these perturbations in the channel profile. A variety of models have been developed to capture the influence of sediment cover on bedrock channel evolution, including the Stream Power with Alluvium Conservation and Entrainment (SPACE) model (Shobe et al., 2017), which builds on the standard stream power model by conserving the mass eroded from the channel bed and allowing it to be transported downstream or deposited in an alluvial layer. The model assumes that channel width scales with discharge rather than allowing for a dynamically evolving channel width. However, sediment may play an important role in the channel’s evolution by abrading the sidewalls and widening the channel in order to accommodate increased sediment flux, which may in turn reduce vertical incision rates. Here we present a modified version of the SPACE model that explicitly calculates channel width in order to test how sediment cover influences channel widening and steepening in response to climate and tectonic perturbations in 2D and at the landscape scale. Like the original SPACE model, our model is implemented using the Landlab toolkit, a python library for modeling earth surface processes. We use our model to explore how feedbacks between sediment production, sediment cover, and channel widening or narrowing may influence patterns and rates of incision during transient responses to changes in uplift and climate. We specifically test how sensitive vertical and lateral incision rates are to pulses of uplift under varying sediment regimes. We also explore the influence of climate by varying precipitation rate. Our model offers an efficient method for modeling dynamic channel width and sediment dynamics that can be coupled with existing Landlab components to address a wide range of geomorphic problems in two dimensions.
Temperature-corrected calibration of GS3 and TEROS-12 soil water content sensors 
Authors: Nasta Paolo , Bogena Heye R. , Huisman Johan Alexander , Sica Benedetto , Lazzaro Ugo , Coccia Francesca , Mazzitelli Caterina , Vereecken Harry , Romano Nunzio
Published: March 2024

The continuous monitoring of soil water content is increasingly carried out using low-cost capacitance sensors that require a site-specific calibration to correlate sensor readings to apparent dielectric bulk permittivity (Kb) and soil water content (θ). Factory calibrations do not take into account the temperature effects on the bound water fraction associated with clay mineral surfaces, making it challenging to convert Kb to θ especially in fine-textured soils. Here, we present a new multi-point calibration approach that accounts for temperature effects in two soils with medium to high clay content. For this purpose, a laboratory calibration strategy for capacitance sensors was developed using repacked soil samples in which the Kb-θ relationship was determined for temperature steps from 10 to 40 °C. We tested this approach using the GS3 and TEROS-12 sensors (METER Group, Inc. USA; formerly Decagon Devices), which measure Kb and soil temperature (T). Direct measurements of θ were obtained using the thermo-gravimetric method.
We found that Kb has an impact on T for both the loam and clay soils with contrasting T-Kb relationships. Despite the identical measuring principle, GS3 and TEROS-12 showed distinct T-Kb relationships, indicating that sensor- and site-specific calibrations are needed. The measured data were fitted using a linear function θ = a √Kb+b with temperature-dependent coefficients a and b. We found that the slope, a(T), and intercept, b(T), of the loam soil were different from those of the clay soil. By including a temperature correction in this equation resulted in a low RMSE, ranging from 0.0070 to 0.033 cm3 cm-3, which was considerably lower than the RMSE obtained from factory calibration (0.046 to 0.11 cm3 cm-3). Finally, we demonstrated how the proposed calibration method can be applied at two Mediterranean test sites.  The new calibration method, unlike the factory calibration, led to a significant improvement in the agreement between θ-values from a network of GS3 sensors, installed in these test sites, and independent θ-values from Cosmic Ray Neutron Sensors (CRNS).
 
Smart Grid Optical Fiber Network for Earthquake Early Warnings
Authors: Awad Hasan , Usmani Fehmida , Virgillito Emanuele , Bratovich Rudi , Straullu Stefano , Proietti Roberto , Pastorelli Rosanna , Curri Vittorio
Published: March 2024

Optical fiber networks, commonly known for data communications, could be extended beyond their conventional use. In our research, we propose a groundbreaking method by leveraging these existing terrestrial optical networks as wide distributed array sensors for earthquakes early detection. This approach is centered around the use of light polarization changes within the fiber cable, analyzed through a robust machine learning model that provide early warning alerts upon Primary earthquake waves arrival that induce strain, and precede earthquake’s destructive Surface waves. Unlike previous methods such as Distributed Acoustic Sensing and Frequency Interferometric Techniques, our approach avoids the use of expensive and specialized hardware. We introduce a centralized smart grid system that exploits the network’s existing terrestrial infrastructure, yet ensure cost effective and high efficient network modeling for initiating emergency plans and earthquake countermeasures. Our initial studies started by conducting experimental tests on a deployed fiber ring in Turin, Italy, using commercial Intensity Modulated – Direct Detection transceivers and polarimeters as polarization sensing devices, yield in promising results. Additionally, we identified the Primary waves arrival for a real 4.9 magnitude earthquake struck in the Marradi region, central Italy, with a 98% accuracy rate. This achievement was the result of a python-based waveplate model empowered by machine learning algorithm.  Basically, when an earthquake occurs, networks nodes communicates with a centralized optical network controller that detects alterations in the light’s state of polarization by leveraging a pre-trained machine learning model. Upon the model confirmation, the controller activates early warning system in accordance with a predetermined emergency response mechanism. Building up on these findings, our current objective is to explore the impact of earthquake depth on seismic wave characteristics and their influence on light’s polarization to further investigate the potential of this advanced smart grid methodology. We aim to analyze real ground motion waves generated by two distinct earthquakes with same magnitudes but different depths. This knowledge is crucial in refining our machine learning model, which in turn will refine model prediction capabilities. Our approach promises more efficient optical network, by transforming the network into long range seismic sensors.
Microseismic records based on machine-learning reveal the crustal anisotropy beneath the southern Sichuan-Yunnan block in the SE Tibetan Plateau
Authors: Li Ying , Gao Yuan , Tian Jianhui
Published: March 2024

Complex tectonics and significant crustal anisotropy are observed at the intersection of the Red River Fault (RRF) and the Xiaojiang Fault (XJF) in the southern Sichuan-Yunnan block, in the SE Tibetan Plateau. The fast S polarization of upper crustal anisotropy varies from NW-SE in the west to NE-SW in the east near the Yimen region. However, small-scale anisotropic structures remain challenging due to limited measurements. Using two years of seismic data from the temporary linear HX Array and permanent stations, this study employed machine learning to construct a high-precision earthquake catalog for S-wave splitting, revealing the upper crustal anisotropy. The new catalog has nearly twice as many earthquakes as the China Earthquake Networks Center. The seismicity is concentrated in the Yimen region with various strike-slip faults, which has a strong correlation with high- and low-velocity boundaries, especially near the edge of the low-velocity zone. Spatial variations in upper crustal anisotropy along the HX Array correspond to geological structures and regional stress. Despite a dominant NE-SW PFS (i.e., fast S-wave polarization) in the Yimen region, stations show dual dominant directions with high values of DTS (i.e., delay times between split S-waves), indicating intricate tectonic and stress interactions. The middle segment of the RRF shows significantly lower DTS values than either side, along with a vertically distributed earthquake swarm, possibly indicating locked structures with high seismic hazard. A comparison between the upper and whole crustal anisotropy reveals consistent deformation within blocks and nearly orthogonal deformation near the RRF and the XJF. The boundary faults likely play a crucial role in influencing the crustal anisotropy both horizontally and vertically. The faults like the Shiping-Jianshui and the Puduhe, running parallel to the RRF and the XJF, are believed to affect the crustal structure. This study highlights that microseismic detection enhances earthquake catalog completeness, providing insights into detailed structures [supported by NSFC Projects 42074065 & 41730212].
Contrasting stratospheric chlorine processes on volcanic and wildfire aerosols
Authors: Wang Peidong , Solomon Susan , Kinnison Douglas
Published: March 2024

Combining satellite data from HALOE (The Halogen Occultation Experiment, available from 1991-2005) and ACE-FTS (Atmospheric Chemistry Experiment - Fourier Transform Spectrometer, available from 2004-present), we quantified the stratospheric chlorine processes after the 2020 Australian wildfire and major volcanic eruptions (1991 Pinatubo, 2015 Calbuco, and 2022 Tonga). The 2020 Australian wildfire was the largest wildfire since the satellite era. This wildfire released of the order of 1 Tg of aerosols into the stratosphere, comparable to small-scale volcanic eruptions. Despite this rather small amount of stratospheric aerosol loading, its impact on the stratospheric chlorine reservoirs (HCl and ClONO2) was enormous. In contrast to volcanic eruptions, most of the aerosols from wildfires are organics, which could lead to different chemical processes from inorganic sulfates. We use these observations to demonstrate that wildfire aerosols uptake HCl much more efficiently than volcanic aerosols, especially at temperatures warmer than 200 K. Furthermore, while the 1991 Pinatubo eruption injected an order of magnitude more aerosol into the stratosphere than the 2020 Australian wildfire, we show that the two events led to a similar amount of HCl decrease in the mid-latitude and polar region. Most of the decrease in HCl after the 2020 Australian wildfire was balanced by an increase in ClONO2; whereas calculated ClONO2 remained unchanged after the 1991 Pinatubo eruption (indicated by model simulations). With current climate change projections, we are expected to have more frequent wildfires in the future, and this more efficient HCl loss pathway poses new threats to the recovery of the stratospheric ozone layer.
Antarctic tropopause by ozonesonde profiles from the Polar Atmospheric Chemistry at the Tropopause PACT database
Authors: Milinevsky Gennadi , Ivaniha Oksana , Klekociuk Andrew , Yu Ruixian , Evtushevsky Oleksandr , Grytsai Asen , Shi Yu
Published: March 2024

Stratosphere–troposphere exchange can be considered globally within the framework of the atmosphere's general circulation as the transfer of air masses through the tropopause with ascending (descending) flows in the tropics (extratropical latitudes). The report aims to study the features and behavior of thermal and chemical tropopause to determine the troposphere-stratosphere interaction in the ozone hole in the Antarctic region. To calculate the height of the polar tropopause based on vertical temperature profiles (thermal tropopause), ozone profiles (ozone tropopause), and water vapor ("water" tropopause), we used the Polar Atmospheric Chemistry at the Tropopause (PACT) database that provides high-resolution measurements from polar ozonesondes flown from selected Antarctic sites. The vertical resolution of the raw ozonesonde measurements is typically 10 meters, which allows us to determine the tropopause height with high accuracy. We calculated the monthly mean ozone and thermal tropopause height variations from the PACT data. Seasonal thermal tropopause and ozone tropopause height monthly changes at the selected Antarctic stations were examined. We developed an algorithm for determining the tropopause height based on vertical profiles of water vapor, studied the relative position of the three tropopauses by altitude, and revealed the anticorrelation of the water and thermal tropopauses. The analysis shows that during the ozone hole formation period in August–September, the vertical stability of the upper troposphere and lower stratosphere is disturbed, and the ozone tropopause can drop below the thermal one, which can create conditions for the spread of stratospheric air into the troposphere and cause conditions for the stratosphere–troposphere exchange.This work was partly supported by the projects of the Australian Antarctic Division and by the International Center of Future Science, Jilin University, under Grant No G2023129024.
Starting of Qilianshan’s uplift since Cenozoic and its implications for Tibetan mantle dynamics
Authors: Pang Jianzhang , Zheng Dewen , Ma Yan
Published: March 2024

The Qilian Shan, located at the northeastern edge of the Tibetan Plateau, plays a crucial role in understanding the Plateau's uplift and expansion processes. There are two classical models, one proposes a progressive expansion of the thickened crust, while the other suggest that the northern extent of the Plateau was established soon after the collision between India and Eurasia around 50 Ma ago. Nevertheless, a recent study introduces a more complex scenario, proposing a pulsed uplift of the northern Tibetan Plateau starting around 30 Ma (Wang et al., 2022). These models heavily rely on the spatial and temporal evolution of the Qilian Shan. Nevertheless, the exact timing and mechanisms of its evolution remain elusive.To delve into the growth history of the southern Qilian Shan, we have obtained apatite fission track data from the Dachaidan Shan and the northern Qaidam basin. Notably, AFT ages from the Dachaidan Shan transect (ranging from 35 Ma to 10 Ma) vary significantly with elevation. An intriguing observation is a possible break in slope at 18±2 Ma, which is interpreted as indicating the onset of intense exhumation in the southern Qilian Shan. Furthermore, within the Qaidam basin, a total reset AFT age group of 14.8±3.8 Ma was found in Jurassic strata but not in Cretaceous and Cenozoic strata. This suggests a rapid cooling event occurred at that time, which we interpret as marking the initial deformation of the northern margin of the Qaidam basin.In combination with previous studies on the deformation time of the Qilian Shan, our findings suggest that the initial deformation of the Qilian Shan occurred in the Middle Miocene, followed by a multi-step outward expansion. This synchronized expansion might have been triggered by the removal of mantle beneath northern Tibet.Wang, W., Zhang, P., Garzione, C.N., et al., 2022. Pulsed rise and growth of the Tibetan Plateau to its northern margin since ca. 30 Ma. Proceedings of the National Academy of Sciences 119, e2120364119.This research was supported by the State Key Laboratory of Earthquake Dynamics (LED2021A05) and the National Natural Science Foundation of China (42272269).
Remote Sensing Monitoring and Evaluation of Ecological Environment and Function in Ecological Protection Red Line Area of Yalong River under Climate Influence
Authors: Wang Bowei , Yuan Yue
Published: March 2024

The Yalong River originates from the Tanggula Mountains in the northeast of the Qinghai Tibet Plateau and is an important water and energy base in southwestern China. It is located at the junction of the Qinghai Tibet Plateau and the subtropical zone and has rich biodiversity. Protecting the ecological environment of the Yalong River is of great significance for maintaining regional ecological balance and biodiversity.Ten remote sensing inversion indexes related to the ecological environment were selected, combined with principal component analysis (PCA), the ecological environment index (RSEI) and water conservation function index (WCI) were constructed and classified, the ecological environment, water conservation capacity and temporal and spatial pattern changes of the red line area for ecological protectionof Yalong River source from 2000 to 2019 were evaluated. The results show that: (1) The RSEI of eastern part was slightly better than that of the western part, the area with excellent evaluation grade accounted for 15.96%, the good accounted for 51.28%, the general accounted for 27.61% and the poor accounted for 5.13%. The propotion of regions with slight improvement in RSEI trend was 52.96%. The northeast showed a slight improvement and the east showed a slight degradation. The degraded areas were scattered. (2) The ecological function of water conservation remained good, the WCI of the north was better than that of the south. The areas with worse, poor and general evaluation grades were mainly distributed in the central and south region, and were scattered. The proportion of areas with excellent WCI rating accounted for 43.22%, the good accounted for 35.71%, the general accounted for 17.45%, the poor accounted for 3.48% and the worse accounted for 0.02%. The change trend of WCI was mainly slightly improvement in the northwest and had greatly spatially difference, while it significantly improved in the south. (3) Since 1990, the temperature rising rate in the study area was 0.56 ℃/10a, the average temperature rising rate in the growing season was 0.1 ℃/10a, the precipitation rising rate was 27.7 mm /10a, and the average precipitation rising rate in growing season was 83.5 mm/10a. (4) Overall, from 2000 to 2019, the climate warming and humidifying in the study area was beneficial to vegetation restoration, carbon storage and reduction of soil erosion, and the ecological environment and water conservation function were improved.