bluuebunny/crossref_metadata_2025 huggingface dataset:
Data assimilation of NOAA surface and MIPAS satellite observations for improvements towards the global budget of carbonyl sulfide
Authors: Ma Jin , Glatthor Norbert , von Hobe Marc , Montzka Steve A. , Krol Maarten
Published: February 2023

Carbonyl sulfide (COS) is a long-lived trace gas with an average tropospheric mixing ratio of approximately 485 pmol mol-1 and a lifetime of about 2 years. In the absence of a significant atmospheric trend, its budget is considered balanced, but significant uncertainties remain on individual sources and sinks. Although challenging, accurate quantification of the COS budget is important because COS uptake by terrestrial biosphere has the potential to be used for improved assessment of Gross Primary Productivity (GPP). Here, we will report inversion progress of optimizing COS global budgets by using TM5-4DVAR. To this end, we assimilate data from the MIPAS limb sounder onboard the ENVISAT satellite that measured atmospheric emission profiles down to the upper troposphere from 2002 – 2012. Tropospheric COS retrievals are assimilated together with NOAA COS surface observations, and a bias correction scheme is employed to correct for potential calibration differences. We will show that: 1) inversion experiments close the budgets and are in favor of reduced biosphere uptake; 2) co-assimilation and bias correction scheme improve fitting ground and satellite retrievals and validation against HIAPER Pole-to-Pole Observations (HIPPO); 3) the prior flux errors are also important for achieving more realistic inversions.
Unbending connects sea level to faulting at fast-spreading mid-ocean ridges
Authors: Katz Richard F. , Huybers Peter
Published: February 2023

Topographic spectra of abyssal hills from fast-spreading mid-ocean ridges have concentrations of power at Milankovitch frequencies and, in particular, around 1/(41 ka) [1].  This frequency corresponds to variations in Earth’s obliquity and is prominent in many climate records, including Pleistocene sea-level variations. Sea-level variations are understood to induce variations in magma supply to the ridge axis [2]. How might these magma-supply variations pace the faulting that creates abyssal hills?  We hypothesise that magma-supply variations introduce a perturbation to elastic plate thickness that is correlated with crustal thickness [3]. Building on Roger Buck’s theory for plate unbending and faulting at fast-spreading ridges [4], we show how thickness perturbations lead to concentrations in bending stresses in thinner parts of the plate.  These concentrations can be significant relative to background unbending stresses and may therefore pace faulting, depending on their amplitude and wavelength.  Using perturbation analysis and numerical solutions of Euler-Bernoulli beam theory, we develop predictions for fault spacing as a function of spreading rate, amplitude of magma supply variations, and other physical parameters.[1] Huybers, Peter, et al. "Influence of late Pleistocene sea-level variations on mid-ocean ridge spacing in faulting simulations and a global analysis of bathymetry." PNAS https://doi.org/10.1073/pnas.2204761119 [2] Cerpa, Nestor G., David W. Rees Jones, and Richard F. Katz. "Consequences of glacial cycles for magmatism and carbon transport at mid-ocean ridges." EPSL https://doi.org/10.1016/j.epsl.2019.115845 [3] Boulahanis, Bridgit, et al. "Do sea level variations influence mid-ocean ridge magma supply? A test using crustal thickness and bathymetry data from the East Pacific Rise." EPSL https://doi.org/10.1016/j.epsl.2020.116121 [4] Buck, W. Roger. "Accretional curvature of lithosphere at magmatic spreading centers and the flexural support of axial highs." JGR https://doi.org/10.1029/2000JB900360 
Fieldwork anytime!——The functions and applications of DDE-Outcrop3D
Authors: Zhong Hanting , Chen Jianhua , Lin Zongqi , Wang Shuaiqi , Hou Mingcai , Li Yalin , Wang Chengshan
Published: February 2023

Outcrops are the focus of geological research. Oblique photogrammetric technology with the aid of unmanned aerial vehicles can build 3D digital outcrop models and further help to achieve visualization research of outcrops, which provides new ideas to solve the problems of low efficiency, high risk, and poor data reusability that exist in traditional geological research methods. This paper investigates the key technologies of 3D modeling of oblique images, 3D visualization of digital outcrops, and visualization of panoramic models, and design and implement a Web platform named DDE-Outcrop3D for real-scene 3D digital outcrops based on the Cesium open-source 3D earth engine. The platform achieves the visualization of high-precision 3D models of geological outcrops and combines the outcrop-related information such as text, pictures, videos, panoramas, documents, observation stops, and geological plotting with 3D outcrop models, realizing upload and panoramic roaming of 3D models of outcrops and self-supply, sharing, and visualization of outcrop-related information. As the first choice for the virtual field trips of the 21st International Sedimentological Congress, the platform has been successfully applied to 12 of the 15 field routes. Compared with traditional geological research methods, the visualization of 3D outcrops can help geologists understand the spatial and temporal distribution of geological phenomena and features of outcrops more comprehensively and intuitively. This platform also achieves the co-construction and sharing of resources of outcrops under digital environment, saving the time and economic costs of geological expeditions.Keywords: Oblique photogrammetry, Real-scene 3D outcrops, Cesium, Visualization platform
Analysis of GLORI GNSS-R airborne measurements for soil moisture estimation
Authors: Zribi Mehrez , Dassas Karin , Fanise Pascal , Dehaye Vincent , Le Page Michel , Boone Aaron
Published: February 2023

Soil moisture plays an essential role in understanding the soil-vegetation-atmosphere interface and in managing water resources for irrigation. In recent years, the Global Navigation Satellite System Reflectometry (GNSS-R) technique has shown great potential in estimating and monitoring this parameter. In this context, various global operational products are already offered based on data from the CYGNSS satellites. In this study, we propose an analysis of an airborne campaign with measurements from the GLORI instrument at the Urgell agricultural site, in Spain. It is a polarimetric instrument allowing acquisitions in both LHCP (Left Hand Circular Polarized) and RHCP (Right Hand Circular Polarized) polarizations and L1 frequency band.In parallel with three flights carried out on the study site in July 2021, various in situ measurements are carried out on twenty reference plots (soil moisture, Leaf area index, soil roughness). An analysis of the incidence angle effect on the GNSS-R reflectivity measurements is proposed. It illustrates larger effects for RHCP polarization. A normalization of data for one incidence angle is proposed. A sensitivity analysis of GLORI measurements to soil moisture is then discussed. The effect of vegetation cover on the degradation of this sensitivity is highlighted. The LHCP polarization displays a higher sensitivity to soil moisture.An inversion model based on the two-omega approach is calibrated and validated with the in situ data acquired on the reference plots. Reflectivity is simulated as a function of soil moisture and the optical Normalized Difference Vegetation Index (NDVI) index which describes the dynamics of the plant cover. An RMSE close to 0.07m3/m3 is retrieved for soil moisture validation.Soil moisture maps, based on the application of the inversion model, are proposed at a spatial resolution of 100 m for three realized flights. A correlation with precipitation events, as well as the presence or absence of irrigation is clearly observed.
Effects of mixing at pore intersections on large-scale dissolution patterns
Authors: Sharma Rishabh Prakash , Kang Peter K. , Szymczak Piotr
Published: February 2023

Dissolution of carbonate rocks is a complex process in which the interplay of flow, transport, reaction, and geometric evolution plays an important role. The nonlinear couplings between these processes may lead to the formation of intricate patterns, including spontaneously formed channels (wormholes) [1].  It has been long established that the shapes of the dissolution patterns depend on fluid flow and mineral dissolution rates [2]. Recently, it also has become increasingly clear that pore-scale processes can impact large-scale morphologies [3,4]. However, the effects of pore-scale mixing on large-scale patterns remain unclear.In this work, we investigate the effect of pore-scale mixing processes on the evolution of dissolution channels. Pore space is represented by a network of cylindrical tubes with the diameter of each segment increasing in proportion to the local reactant consumption. The inlet concentration of each pore is controlled by local mixing rules. Two different mixing protocols are considered: full mixing, in which the incoming reactant fluxes are assumed to be completely mixed at the intersection, and streamline routing, where the tracer follows the streamlines into the outgoing pores. We found that streamline routing enhances the flow focusing particularly strongly in moderate Damköhler number regimes where relatively wide dissolution channels appear spontaneously in the system. With the same initial conditions as the full mixing case, the winning channels obtained with streamline routing not only propagate faster but also could grow at a different location in the system. The enhanced flow focusing caused by streamline routing produces thinner wormholes and leads to shorter breakthrough times. Lastly, the evolution of velocity distribution is also found to be distinctive depending on the mixing rule.[1] Hoefner, M. L. and Fogler,  H. S. AIChE J. 34: 45–54, 1988[2] Golfier, F., et al.  J. Fluid. Mech. 457: 213-254, 2002[3] Li, L., Peters, C. A., & Celia, M. A. Adv. Water Res., 29: 1351–1370, 2006[4] R. Roded, P. Szymczak, R. Holtzman, Geophys. Res. Lett. 48:e2021GL093659, 202
Increased impact of the El Niño–Southern Oscillation on global vegetation under future warming environment
Authors: Le Thanh
Published: February 2023

There are broad impacts of vegetation changes on water cycle, regional climate, carbon budget and ecosystems productivity. Hence, further understanding of the drivers of future vegetation changes are crucial. The El Niño–Southern Oscillation (ENSO) is a main mode of interannual climate variability and is expected to influence vegetation at a global scale. Nevertheless, little is known about the causal impacts of ENSO on future vegetation cover under warming environment and changes in land use. Here, we investigated the links between ENSO and vegetation using leaf area index (LAI) data over the 2015-2100 period from Coupled Modeling Intercomparison Project Phase 6 (CMIP6). Our results show that the vegetated areas influenced by ENSO are projected to increase by 3% and 1% of total land areas in the 21st century of the scenarios SSP2-4.5 and SSP5-8.5, respectively. These results suggest that the impacts of ENSO on global vegetation may increase in the future. While uncertainty remains in several regions for the causal link between ENSO and vegetation changes, this study provides insights on the future impacts of ENSO on global vegetation dynamics.
From vegetation to soil: Organic matter dynamics in young temperate riparian forests
Authors: Siegfried Lila , Vittoz Pascal , Verrecchia Eric
Published: February 2023

The future of wetland forests in temperate regions interests many nature conservationists. Indeed, due to a mosaic of environments influenced by the availability and the dynamics of water, these ecosystems have a specific biological diversity and a potential to store carbon. Sadly, wetland forests are threatened and increasingly rare in Europe, due to human pressure on land, in a context of biodiversity loss and climate change. An important part of these ecosystems is now only semi-wild, and the dynamics of their organic matter is still poorly known. This study focuses on the riparian forests in nature reserves along the lake of Neuchâtel (Switzerland). These forests colonised newly available areas, emerged from the lake after a 3-m drop of the water level at the end of the 19th century.The aim of the project is to better understand the dynamics of different types of wetland forests along a gradient of water level. Vegetation communities, organic matter and soil were studying in four forest types: wet black alder forests, humid alluvial white alder forests, ash forests and summer dry pine forests. Measured factors include water table fluctuations, soil litter inputs, organic matter decomposition rate, soil respiration, and soil organic matter characteristics, in relation to vegetation type. The first results show a difference in the organic matter pathways between the four habitats. Water dynamics appears to be one of the main drivers in the fate of organic matter. Wet black alder forests have low soil respiration, but a high rate of organic matter decomposition, as contrarily to the drier ash forests. This project will contribute to improve the conservation of these threatened ecosystems.
Effects of atmosphere-ocean interactions on late Holocene climate in the Arctic-Subarctic region
Authors: Bauch Henning
Published: February 2023

After the last glaciation numerous temperature sensitive climate proxies from around the Arctic – ice cores, terrestrial and marine archives alike – show a tight connection to northern insolation with highest temperatures noted in the early Holocene. However, until the mid-Holocene (5-6ka; start of neoglaciation) all environmental change and reorganization occurred under circumstances still caused by deglaciation and global sea-level rise. Thus, the situation observed since then is interpreted to be mainly driven by a kind of ocean-atmospheric system that has little in common with the time before. In the Arctic the flooding of the vast shelves ended thereby massively expanding the area of winter sea-ice. And in the Nordic Seas water fronts were established which caused intensification of the gyre systems leading to the modern-like circulation pattern during the past 4kyrs. In several records these past 4 millennia were relatively cool. In the largest Arctic delta (Lena) peat-based island accumulation started at 4ka and another major change in growth occurred after 2.5ka in both, accumulation and species composition.Neoglacial cooling in the colder Nordic Seas is witnessed by a persistent sedimentation of ice-rafted debris (IRD) after 6 ka, a trend which continued until recent time. Although within the eastern, Atlantic-influenced sector warm conditions persisted until about 1 ka, as seen in both planktic and benthic O-isotopes, variability among foraminiferal species would indicate major surface changes, as the abundance of the polar species increased to 70 % since then (in the Little Ice Age). That drastic increase was associated with highly variable O-isotope values throughout the entire water column. Thus, for the Little Ice Age the particular situation caused a rerouting of polar water masses and sea-ice far into the eastern Nordic seas. The major force behind such centennial-long climatic events must be sought in a complex atmosphere-surface ocean interaction rather than in the often-mentioned meridional ocean overturning circulation. Thus, spatial expansion of sea-ice impacts both the polar vortex and the temperature gradient between the high and low latitudes thereby exerting climate pressure on regions well beyond the Arctic realm.
Impacts of Atlantic Multi-decadal Variability on the mid-latitude atmosphere
Authors: Patterson Matthew , Woollings Tim
Published: February 2023

The large amplitude of low-frequency sea surface temperature (SST) variability in the North Atlantic, often known as Atlantic Multi-decadal Variability (AMV), raises the question of what impact this phenomenon has on atmospheric circulation. However, the coupled nature of AMV, makes disentangling the influence of the ocean on the atmosphere and that of the atmosphere on the ocean, challenging. This problem is further confounded by the relatively short observational record, when considering decadal to multi-decadal timescales.To address this, we utilize information from both SSTs and ocean-atmosphere turbulent heat fluxes,  in a single index, to separate the influences that the ocean and atmosphere have on one another. This technique is then applied to both free-running coupled simulations and observations. This methodology will help further our understanding of North Atlantic variability on long timescales.
Reconciling farmers’ expectations with the demands of the emerging UK agricultural soil carbon market
Authors: Ziv Guy , Phelan Lisette , Chapman Pippa
Published: February 2023

This paper explores farmers’ and land managers’ perceptions of the emerging agricultural soil carbon market in the UK and examines their willingness to adopt soil health management practices to enhance and/or maintain soil carbon stocks and enthusiasm for and interest in participation in soil carbon sequestration schemes. Data were collected through online questionnaires administered to 100 farmers and six organisations responsible for the operationalisation and development of carbon codes in the UK using online questionnaires. The results indicate that farmers’ prior adoption of practices that promote soil health does not necessarily translate into a willingness to adopt additional practices and/or “buy into” soil carbon sequestration schemes. Farmers have reservations about planning and implementing soil carbon projects due to the terms and conditions associated with participation in the emerging UK agricultural soil carbon market. Although the carbon market may attract new entrants, early adopters of soil health management practices are likely to be excluded from soil carbon sequestration schemes established by public and private sector actors based on additionality criteria. The results of this study also suggest early adopters’ expectations regarding their scope to derive benefits from participation in the carbon market are at odds with the demands of the carbon market as articulated by the carbon codes driving the development and growth of the market. These results highlight that the key role that early adopters may play in encouraging new entrants to engage with the carbon market should not be underestimated. It contends that enhancing the transparency, robustness, and integrity of the carbon market hinges on incentivising early adopters to adopt additional practices that promote soil health and facilitate their participation in the market, alongside new entrants. The paper argues that kick-starting and supporting the growth of the agricultural soil carbon market is contingent on reconciling farmers’ expectations with the demands of the market, during an initial transition period, through flexible implementation of rules and regulations outlined by carbon codes regarding soil carbon sequestration and storage in agricultural soils.
A Detailed Investigation and Modeling of Natural Radioactivity Levels and Radon/Thoron Release Potentials in Southeastern Ireland
Authors: M. Aghdam Mirsina , Rocha Carlos , Crowley Quentin
Published: February 2023

The Irish population receives most of its annual average radiation dose from radon (including thoron), but there is considerable spatial variation in parameters that affect these concentrations. An assessment of natural radioactivity levels and radon and thoron exhalation rates was conducted in County Carlow and Kilkenny, where evidence of "high indoor radon" concentrations was found. Background data used in this study include airborne radiometric data and stream sediment geochemistry from the TELLUS project, and indoor radon concentrations as supplied by Ireland’s Environmental Protection Agency. Based on the analysis of these datasets, a set of soil samples was taken from the study area in the first phase of the project. The exhalation rates of radon and thoron for collected samples were determined in the laboratory. The resultant data were classified based on geological and soil type parameters. Geological boundaries were found to be robust classifiers for radon exhalation rates and radon-related variables, whilst soil type classification better differentiates thoron exhalation rates and correlated variables. In the second part of the project, a detailed investigation of geogenic radon potential (GRP) was carried out in an identified hotspot area near Graiguenamanagh town (County Kilkenny, Ireland) by using spatial regression analysis of radon-related variables to evaluate the exposure of people to natural radiation (radon, thoron and gamma radiation). To model radon release potential at different points, an ordinary least squared (OLS) regression model was developed in which soil gas radon (SGR) concentrations were considered as the response value. Proxy variables such as radionuclide concentrations obtained from airborne radiometric surveys, soil gas permeability, distance from major faults, and a digital terrain model were used as input predictors. ArcGIS and QGIS software together with XLSTAT statistical software were used to visualise, analyse and validate the data and models. The proposed GRP models were validated through diagnostic tests. Empirical Bayesian kriging (EBK) was used to produce a map of the spatial distribution of predicted GRP values and to estimate the prediction uncertainty. The methodology described here can be extended for larger areas and the models could be utilised to estimate the GRPs of other areas where radon-related proxy values are available.
Multidecadal variation of the inner core rotation and implications for global dynamics
Authors: Yang Yi , Song Xiaodong
Published: February 2023

Differential rotation of Earth’s inner core relative to the mantle above plays an important role in core dynamics and the core-mantle coupling. The rotation has been inferred from temporal changes of repeating seismic waves traversing the inner core. In our recent study1, we report remarkable observations that all the paths previously with significant temporal changes have now exhibited little changes over the recent decade. The consistent global pattern suggests strongly that the inner core rotates as a whole and the rotation has paused in the recent decade with a net torque of ~1016 Nm. Furthermore, the recent pattern seems associated with a gradual turning-back as a part of a long-period (about seven decades) oscillation with another turning point in the early 1970s. The multidecadal periodicity coincides with changes in several other geophysical observations, including the global mean temperature2, the global mean sea level rise3, and especially the length of day (LOD) and magnetic field variations4, pointing to a common resonating system of the Earth. Our observation provides important constraints to geodynamo models and the mantle-inner core gravitational coupling and offers key evidence for dynamic interactions between the Earth’s layers from the deepest interior to the surface.References: 1. Yang, Y., & Song, X. (2023). Multidecadal variation of the Earth’s inner-core rotation. Nature Geoscience (in press). https://doi.org/10.1038/s41561-022-01112-z2. Zotov, L., Bizouard, C., & Shum, C. K. (2016). A possible interrelation between Earth rotation and climatic variability at decadal time-scale. Geodesy and Geodynamics, 7(3), 216–222. https://doi.org/10.1016/j.geog.2016.05.0053. Ding, H., Jin, T., Li, J., & Jiang, W. (2021). The contribution of a newly unraveled 64 years common oscillation on the estimate of present-day global mean sea level rise. Journal of Geophysical Research: Solid Earth, 126(8). https://doi.org/10.1029/2021JB0221474. Roberts, P. H., Yu, Z. J., & Russell, C. T. (2007). On the 60-year signal from the core. Geophysical and Astrophysical Fluid Dynamics, 101(1), 11–35. https://doi.org/10.1080/0309192060108382
Using a Monte Carlo framework for assessing future costs of major transport disruptions from seldom occurring natural hazards
Authors: Klæboe Ronny , Eidsvig Unni
Published: February 2023

A prototype tool (DynEcon) for dynamic societal cost benefit analyses was used to produce simple estimates of future costs of traffic disruption caused by one or more rail and road bridge failures from 100-year flooding(s) in the Santarem Region. The focus was on quantification of different types of consequences. A project period until year 2100 was chosen to include adverse events in the far future. Future private and professional vehicle flows before and after disruptions were calculated for 36 scenarios considering declining rural and semi-rural populations destinations and increasing GDP over time. Potential cascading effects from detours and mode transfer at future time points were estimated. The additional fuel and vehicle costs for personal cars and trucks, time losses for professional and private drivers, and external costs for rural and semi-rural population subjected to increased traffic were estimated. The sizes of these costs, depend on the size and composition of the vehicle fleets at time of each disruption. Local and global emissions from fossil fuels the next twenty years will be reduced as the older most polluting vehicles in the vehicle fleets are phased out and newer vehicles must satisfy even more stringent emission and design standards. In addition, EC greening policies and electrification will reduce the amounts of combustion related pollutants dramatically. Prices of Diesel and Petrol were assumed to increase over time. The costs of accidents have decreased due to improved protection from the vehicles and is predicted to continue to decrease due to more intelligent vehicles and smart road infra-structure. Noise, air-pollution due to road wear, and road maintenance costs per km were assumed to remain stable. Costs of CO2-emissions and time delay costs of private and professional drivers were modelled as increasing over time. The additional disability-adjusted life years(DALYs) from local air pollution and noise, were estimated using exposure effect relationships and DALY impact estimates from WHO. A monetary DALY-value was assigned, and the sum costs calculated. To harmonize cost estimates for Portugal having a lower GDP than Norway, costs were scaled down.The dynamic cost benefit tool applies Monte Carlo simulations in a two-step procedure. In the first step a population of e.g. 1000 sets of 100-year flooding events occurring between 2021 and 2100 are generated using knowledge on climate change, flooding characteristics, scour etc. Future annual costs until 2100 are generated using growth models. Since all parameters and growth models are associated with uncertainties, the second step derives the uncertainty distribution of economic result indicators and confidence intervals. An online web-based Monte Carlo framework such as DynEcon could enable researchers to cooperate on different parts of the patchwork necessary for analyses of resilience policies that include hazards occurring late century.
Common streamflow dynamics unraveled the heavy-tailed flood distributions
Authors: Wang Hsing-Jui , Merz Ralf , Yang Soohyun , Basso Stefano
Published: February 2023

Flood frequency distributions with heavy-tailed indicate a sizable chance of the occurrence of extreme floods. When heavy-tailed flood behavior is reliably identified, flood hazards caused by the unexpected can be reduced. However, for cases with limited or varying record lengths it is challenging to robustly estimate tail behavior with currently used indices, which rely solely on the graphical or mathematical performance of limited observations and are regardless of the physical processes.In this work, we start by analyzing runoff generation processes and show that the hydrograph recession is a proper descriptor of the emergence of heavy-tailed behavior of flood frequency distributions. We then examine it in a large set of seasonal case studies, which encompasses a variety of climate and physiographic conditions across Germany. Our results show that the newly proposed approach can detect cases with heavy-tailed behavior, and compare severity across cases by evaluating their tail heaviness. Remarkably, it displays robust identification of heavy/nonheavy-tailed behavior for cases with short data records, benchmarked against two other frequently used metrics for heavy tails in hydrological studies, i.e., the upper tail ratio and the shape parameters of generalized extreme value distributions.We highlight that the proposed method leverages the information of common discharge dynamics for inferring heavy-tailed flood behavior, which addresses the main limitations of currently used metrics and provides information on the characteristic flood hazard of river basins.This study summarizes results of the DFG-funded project "Propensity of rivers to extreme floods: climate-landscape controls and early detection - PREDICTED" (Deutsche Forschungsgemeinschaft - German Research Foundation, Project Number 421396820).
Study on the Failure Development Process and Energy Evolution of Rock Slope
Authors: Wu Yu Chen , Lo Chia ming
Published: February 2023

The development of landslide often accompanied by accumulation, transfer and dissipation of energy. To understand the energy evolution in rock slope may be beneficial to the clarification of landslide mechanism, which can be took as consultation for landslide hazard assessment and prediction of runout distance of sliding material. Considering numerical method, the details of energy evolution inside the rock mass during the process of slip surface development and movement of debris after rock slope collapse. In this study, two kinds of simplified models were created by distinct element method. One is a cube with given slip surface composed by disconnected small crack. The model was used to simulate development of slip surface. Another is a single cube sliding along a flat wall. The model was used to simulate the moving behavior of single debris after rock slope collapse. A series of model with different inclination angle of wall and material property were created to represent different type of landslide and collision behavior respectively. For each model, the energy data were collected from selected elements which distribute uniformly inside the model. The results show that during the development of slip surface, the cracks propagate and then form the slip surface. The strain energy inside the rock mass near the crack accumulates continuously and drops rapidly soon after the crack propagates through the rock mass. After the slip surface be formed, the slope collapse and the potential energy transfers into kinetic energy. Then the frictional energy and damping energy generated by interaction between debris or between debris and mountainside. The debris travels along slope with high inclination angle rebounds higher after hit the bottom of mountainside, but has lower travel distance than ones travels along slope with lower inclination angle. The debris with lower strength tends to break into smaller pieces, and generates more frictional and damping energy due to higher interaction frequency between small pieces.Keywords: Rock slope, Landslide mechanism, Energy evolution, Distinct element method
Using JULES to Model the Congo Peatlands
Authors: Cook Peter Anthony , Betts Richard , Chadburn Sarah , Burke Eleanor
Published: February 2023

The Cuvette Centrale swamp forest around the Congo river has the most extensive peatland complex in the tropics, but due to its remoteness the peat was only recently discovered.  The international project CongoPeat, which includes scientists from the Republic of the Congo and the Democratic Republic of the Congo and works with the local people of the Cuvette Centrale, is studying the peatlands to determine how they formed and the possible threats since it is vital that the peat is preserved.  While the peatlands are at least 20,000 years old the peat is thin compared to other tropical peatlands of similar age.  The JULES land surface model has been used with a reconstruction of the past annual rainfall and a simulation of other climate variables with the HadCM3 model to simulate the development of the peatlands.  The model results support the hypothesis that a long period of reduced rainfall a few thousand years ago lead to a large loss of peat and recreate the age-depth profiles of the peat in measured soil cores including the feature called a “ghost interval”.  This confirms that a constant high water table is needed to keep decomposition of the peat to a minimum and hence preserve the peatlands.  JULES was then run with future climate projections from five global climate models to simulate how the peatlands could change up to 2100.  In most projections the increased temperatures lead to increased evapotranspiration, lower water tables and increased decomposition of peat.  In most cases peat is lost overall, particularly when rainfall is also reduced further lowering the water tables, in-spite of increased CO2 concentration increasing the amount of vegetation and litterfall while reducing the amount of plant transpiration. The risk to the peatland Carbon is greater at higher levels of global warming. 
Spatio-temporal variation of surface soil hydraulic properties under different tillage and maize-based crop sequences in a Mediterranean area
Authors: Talukder Rasendra , Plaza-Bonilla Daniel , Cantero-Martínez Carlos , Di Prima Simone , Lampurlanés Jorge
Published: February 2023

In arid and semi-arid regions, high intensity rainfall and/or irrigation water drop leads to development of surface crust, and it has the potential to alter surface soil hydraulic properties while also accelerating runoff and erosion. However, the temporal variation of soil hydraulic properties under irrigated conditions due to surface crust under different soil management practices has rarely been studied. On a long-term tillage field experiment (26 years), in Agramunt, NE Spain, a study was carried out using Beerkan infiltration tests in conjunction with the inverse optimization algorithms of  the BEST method (Beerkan Estimation of Soil Transfer parameters) to investigate the effects of surface crusting on the spatio-temporal variation of saturated soil hydraulic conductivity (Ks, mm s-1), sorptivity (S, mm s-0.5), mean pore size (r, mm) and number of hydraulically active pores per unit area (N, m-2). Three tillage systems (intensive tillage, IT, reduced tillage, RT; and no-tillage, NT), two crop sequences (short fallow-maize, FM; and legume-maize, LM) and two positions (within the row of crops, W-row, and between the rows of crops, B-row) were assessed to evaluate the crusting effect on the above-mentioned soil hydro-physical properties. In response to autumn tillage, IT increased Ks and S due to higher r and N, but both declined after 60 days. RT, on the other hand, exhibited resilient to crust formation and despite having a lower N value, maintained comparable Ks and S values. After the spring tillage, its effect was immediately lost because of high-frequency water application, and both IT and RT developed crusted layers, resulting in decreased Ks, S and N. Long-term NT was resilient to form crust and an increasing trend of Ks and S was observed over time, except for the last sampling. Spatial variation (i.e., B-row vs. W-row) of Ks and S was found because of crusting, and independently of crop sequence, non-crusted soils (W-row) had consistently higher Ks (0.021 vs. 0.009 mm s-1)and S (0.65 vs. 0.38 mm s-0.5) than crusted soils (B-row) due to their lower bulk density and N. According to the findings of this study, conservation agriculture practices such as RT and NT improve the stability of surface soil structure and steadily reduce the risk of crust development. Further, surface cover by crops may help to prevent crust formation within the row of crops, improving soil hydraulic conductivity. This enhanced water flow path must not be neglected when measuring infiltration.
Climatic control on the location of continental volcanic arcs
Authors: Paiva Muller Veleda Astarte , Sternai Pietro , Sue Christian , Valla Pierre , Simon-Labric Thibaud
Published: February 2023

Orogens and volcanic arcs at continental plate margins are primary surface expressions of convergent plate tectonics. Although it is established that climate affects the shape, size, and architecture of orogens via orographic erosion gradients, the ascent of magma through the crust and location of volcanoes along magmatic arcs have been considered insensitive to erosion. However, available data reveal westward migration of late-Cenozoic volcanic activity in the Southern Andes and Cascade Range where orography drives an eastward migration of the topographic water divide by increased precipitation and erosion along west-facing slopes. Thermomechanical numerical modeling shows that orographic erosion and the associated leeward topographic migration may entail asymmetric crustal structures that drive the magma ascent toward the region of enhanced erosion. Despite the different tectonic histories of the Southern Andes and the Cascade Range, orographic erosion is a shared causal mechanism that can explain the late-Cenozoic westward migration of the volcanic front along both magmatic arcs. Because volcanic arcs provide a substantial contribution to the evolution of climate across timescales, this recognition provides additional evidence of the tight coupling between climate, surface processes, magmatism, and plate tectonics.  
Long-Lasting Solar Coherent Radio Bursts and Implications for Solar–Stellar Connection
Authors: Yu Sijie , Chen Bin , Sharma Rohit , Bastian Timothy , Mondal Surajit , Gary Dale , Luo Yingjie , Battaglia Marina
Published: February 2023

Discoveries of exo-auroral radio emission in the last two decades have led to an ongoing paradigm shift––many highly circularly polarized intense radio bursts detected in a variety of low-mass stars are likely signatures of auroral activities rather than flare-driven magnetic activities. Such discoveries have opened a new window in probing the magnetic field in stellar/substellar/exoplanetary systems. One of the outstanding challenges in discerning the two scenarios is characterizing the aurora-generating magnetic topologies of the stellar/substellar objects despite their large distances. Thanks to its proximity, the Sun provides much of the detailed context to study radio bursts similar to those in the stellar/substellar regime. A recent imaging spectroscopy observation with the Jansky VLA reveals a new type of radio bursts near a sunspot, which resembles exo-auroral radio emission in the literature both temporally and spectrally. Unlike the planetary aurora scenario, the detected radio signature is identified as electron cyclotron maser (ECM) emission from a sunspot driven by energetic electrons accelerated in flare activities. Comprehensive observations of sunspot auroral radio emissions will not only advance our understanding of the fundamental physical processes of ECM emissions on the Sun but also impose broad implications on stellar/substellar physics and exo-space weather sciences. These efforts will require long-term monitoring by a solar-dedicated, broad bandwidth radio telescope capable of imaging the Sun in dual circular polarization with a high image dynamic range and subsecond time resolution, which is still lacking. In this talk, after a brief introduction to ECM emissions from stars and the Sun, I will discuss the technical requirements in order to make a leap forward in observations of aurora-type ECM emissions from the Sun, and the expected science returns from a superior broadband radio imaging spectropolarimetry capabilities of a next-generation radio heliograph, such as the Frequency Agile Solar Radiotelescope (FASR) concept. 
Technical Improvements on Local Geoid Model Computation
Authors: Li Xiaopeng
Published: February 2023

Since 2014, the National Geodetic Survey started to release experimental geoid models each year based on the new observations collected in the previous year, which are mainly from the contribution of the GRAV-D project (Gravity for the Redefinition of the Vertical Datum). While incorporating large amount of GRAV-D data into these yearly models, the implementation techniques are also polished from year to year, albeit the main architecture is still based on the Molodensky theory, essentially. This paper summarized these main technical improvements on computing local geoid models based on some hands-on experiences. It includes the update of reference models, the stabilization of airborne gravity downward continuation, the modification of residual terrain modeling, the inclusion of density variation effects, and the use of radial basis functions as well as the generalized Stokes’s integration to avoid the higher order terms. Although most of these steps are not totally independent from each other, numerical comparisons are given at each individual step to highlight their specific effects for interested researchers who may need to know the nitty-gritties. Then, the GSVS data are used to demonstrate the overall effects on the final model. Discussions for further improvements will be given at the end of the presentation.
ENSO and extra-tropical ocean variability drives summer drought extremes in the United States
Authors: Gamelin Brandi , Bessac Julie , Rao Vishwas , Altinakar Mustafa
Published: February 2023

Understanding large-scale drought patterns and the mechanisms producing extreme drought events is vital to understanding future drought risks. Here we investigate the influence of teleconnections originating in the Pacific and Atlantic Oceans on regional drought variability in the United States. For this work, the Standardized VPD Drought Index (SVDI) is calculated with Vapor Pressure Deficit (VPD), a method of drought detection based on air temperature and relative humidity, rather than precipitation deficit. This work focuses on summer months between 1980 – 2021, and SVDI was calculated with NASAs North American Land Data Assimilation System (NLDAS) data. Initially, the spatial drought characteristics were extracted from SVDI with EOF analysis. To identify extreme events, a k-means clustering technique was applied to primary principal components, multivariate ENSO index (MEI), and northern hemisphere sea surface temperature anomalies (SSTA). Additionally, to identify mechanisms driving drought variability, statistics from individual clusters (i.e. drought events) are retained for analyses using atmospheric variables (e.g. wind, HGT, and MSLP). Results show large-scale drought in the Central and Southern U.S. stem from mechanisms originating in the northern Pacific Ocean (e.g. PDO and SSTA trends) and northern Atlantic Ocean (e.g. NAO), modulating the variability in the onshore flow along the Gulf of Mexico. However, mechanisms influencing summer drought patterns in the southwestern U.S., especially the recent long-term drought patterns, originate in the equatorial Pacific Ocean and are driven by ENSO related processes.
Constraining the Chemistry of Sub-cm Diagenetic Features with Curiosity's Alpha Particle X-ray Spectrometer
Authors: VanBommel Scott , Berger Jeff , Gellert Ralf , O'Connell-Cooper Catherine , Thompson Lucy , McCraig Michael , Yen Albert , Christian John , Knight Abigail , Boyd Nicholas
Published: February 2023

The Alpha Particle X-ray Spectrometer (APXS) onboard the Mars Science Laboratory (MSL) rover Curiosity has acquired approximately 1,300 geochemical analyses since landing in 2012. The APXS utilizes a combination of X-ray fluorescence and particle-induced X-ray emission to determine the chemical composition of materials within its 15+ mm diameter field of view (FOV) [1, 2]. Diagenetic features provide a means to further understand and constrain the habitability of Curiosity's landing site, Gale crater. These features often present as veins or nodules with an areal extent on the sub-cm scale. APXS analyses of these features therefore contain a mixture of signals from the feature and host substrate.To probe the composition of these sub-FOV features, Curiosity has developed a technique whereby multiple APXS measurements are conducted in close proximity to the primary target (referred to as a raster). The data are then analyzed to not only localize APXS FOVs, mitigating arm placement uncertainty which is on the order of 1-2 cm [2], but also infer the composition of the various endmembers within the workspace. The original raster analysis method (e.g., [2, 3]) has proven useful at deconvolving the chemistry of diagenetic features from the surrounding substrate. However, this method utilizes APXS oxide data as the primary input. These data are derived assuming a homogeneous sample for the purposes of calculating and correcting for matrix effects (the attenuation of induced X-rays by other elements in the sample). In instances of clear chemical heterogeneities, these matrix corrections can result in skewed compositions of the derived endmembers, such as a vein or nodule.Here we present an improvement to this method whereby we utilize low-level data products and isolate matrix effect calculations for each individual endmember (e.g., [4]). The derived results show significant improvements (10-30%) compared to the oxide method in stoichiometric ratios when applied to calcium sulfate veins, an ideal proof-of-concept sample. Subsequent analyses of magnesium-sulfate dominated nodules hint at other potential mobile elements within the fluids present during diagenesis, such as P, Mn, Ni, and/or Zn. Similar elements were enriched in nodules at the Ayton/Groken field site, where P2O5 and MnO concentrations in the nodular material totaled over 25 wt% at a ~2:1 P:Mn molar ratio [4]. The improved analytical method will be particularly useful as Curiosity continues to explore the Marker Band and sulfate unit.[1] Gellert & Clark (2015), Elements, 11.[2] VanBommel et al. (2016), XRS, 45.[3] VanBommel et al. (2017), XRS, 46.[4] VanBommel et al. (2023), Icarus, 392.
Developing an Integrated Water Management Tool for Winnipeg River’s Hydropower System
Authors: Gozini Hamid , Asadzadeh Masoud , Snell Jacob , Koenig Kristina , Gawne Kevin
Published: February 2023

Hydropower is a renewable, economic, and low-emission source of energy and has the flexibility to accommodate different electricity demands. The Province of Manitoba’s current electricity supply is about 97% generated by hydropower, making it potentially vulnerable to climate change. The increase in the annual mean temperature in the Canadian Prairies is twice the rise in the global mean temperature, influencing precipitation patterns which ultimately highlights the importance of understanding the impacts of climate change in Manitoba. A MODSIM-DSS model has been developed for the operation of water control structures and hydropower facilities along the Winnipeg River, including the Rainy and English Rivers, which contains 11% of the hydropower capacity in Manitoba. This simulation model is equipped with parametric rule curves representing the operation of control points in the system. These rule curves are calibrated and evaluated against historically measured and observed data. To better understand potential adaptation responses, the simulation model will be used to project the response of this hydropower system to future climate conditions.