bluuebunny/crossref_metadata_2025 huggingface dataset:
Declining, seasonal-varying emissions of sulfur hexafluoride from the United States
Authors: DeCola Phil , Hu Lei , Ottinger Deborah , Bogle Stephanie , Montzka Stephen , Dlugokencky Ed , Andrews Arlyn , Thoning Kirk , Sweeney Colm , Geoff Geoff , Aepli Lauren , Crotwell Andrew
Published: February 2023

Sulfur hexafluoride (SF6) is the most potent greenhouse gas and its atmospheric abundance, albeit small, has been increasing rapidly. Although SF6 is used to assess atmospheric transport modeling and its emissions influence the climate for millennia, SF6 emission magnitudes and distributions have substantial uncertainties. In this study, we used NOAA’s ground-based and airborne measurements of SF6 to estimate SF6 emissions from the U.S. between 2007 and 2018. Our results suggest a substantial decline of U.S. SF6 emissions, a trend also reported in the U.S. Environmental Protection Agency (EPA)’s national inventory submitted under the United Nations Framework on Climate Change, implying that U.S. mitigation efforts have had some success. However, the magnitudes of annual emissions derived from atmospheric observations are 40 – 250% higher than the EPA national inventory and substantially lower than the Emissions Database for Global Atmospheric Research inventory. The regional discrepancies between atmosphere-based estimate and EPA’s inventory suggest that emissions from electric power transmission and distribution (ETD) facilities and an SF6 production plant that did not or does not report to EPA may be underestimated in the national inventory. Furthermore, the atmosphere-based estimates show higher winter than summer emissions of SF6. These enhanced wintertime emissions may result from increased maintenance of ETD equipment in southern states and increased leakage through aging brittle seals in ETD in northern states in winter. The results of this study demonstrate the success of past U.S. SF6 emission mitigation and suggest substantial additional emission reductions might be achieved through efforts to minimize emissions during servicing or through improving sealing materials in ETD.
Monitoring GLOFs via deep learning-based remote sensing and transfer learning
Authors: Chen Thomas Y.
Published: February 2023

As glacial melting and permafrost melting increase in intensity, regions with glaciers experience higher rates of flooding, which can cause immense economic loss and hundreds of lives lost in glacial lake outburst floods (GLOFs). By training a convolutional neural network (CNN) for this problem on multitemporal satellite imagery, we propose enabling deployable technologies that predict GLOF events and impacts on surrounding areas. In particular, we collect high-resolution satellite imagery data from previous GLOFs around the world, such as in Iceland, Alaska (United States), Pakistan, and Tibet, utilizing repositories provided by ESA and NASA. We curate a dataset based on paired images (pre- and post-GLOF). In this way, we can train the CNN on the change detected between these two instances, which can further aid in predictions in the form of an output from 0 to 10 indicating the severity of damage caused. However, because machine learning algorithms require a large quantity of data, we must also employ transfer learning. We propose a Markov logic network framework to achieve this, incorporating data from events that were not necessarily GLOFs but included glacial movement and/or flooding. When deployed, models like the one we propose can allow for both the monitoring of GLOFs in action as well as predict GLOFs in the near future by assessing changes using data collected from satellites in real time. 
Using Sustainable Storylines to Support Next Generation Science Standards at the Middle School Level – Natural Hazards and Tsunamis
Authors: Kearns Tricia
Published: February 2023

Science educational standards in the United States are not under federal mandates, but rather under state and local jurisdiction. Every few years, most districts and states revise and update their standards. One of the more recent curricular models that has been slowly gaining popularity across the US involves embracing the Next Generation Science Standards. These cover the breadth of K–12 science content standards in schools. They set the expectations for what students should know and be able to accomplish. The NGSS framework supports student growth in science and engineering practices as well as constructing and using scientific ideas to explain phenomena and solve real problems. Many states, schools, districts, and teachers use a storyline approach as a hook to engage student learning. Others use the storyline as a defined series of events and lessons that are driven by student inquiry. A storyline starts with an interesting and perplexing phenomenon. Student-created driving questions will determine the direction of the class storyline. Through inquiry and experimentation, students track their progress and construct understanding to explain phenomena.  In 2022 OpenSciEd, a nonprofit organization funded by the Carnegie Corporation and the Gates, Schusterman, and Hewlett foundations released a sequence of NGSS units themed with storylines for middle school science education. These were funded and created by a consortium of partners including BSCS Science Learning, Boston College, the Dana Center at The University of Texas-Austin, Digital Promise Global, and Northwestern University. This consortium facilitates the creation of sustainable, high-quality, NGSS-aligned science instructional materials that are available cost-free to all interested educators. My school recently adopted OpenSciEd for our middle school science curriculum in grades 6-8. This poster session will demonstrate how the 6.5 OpenSciEd Unit on Natural Hazards addresses the use of a storyline to answer the unit question, “Where do natural hazards happen, and how do we prepare for them?” Tsunamis are the central focus of this unit. The anchoring phenomenon is designed to enable students to consider methods in which scientists detect tsunamis and how warning systems are engineered. Students ponder ways to mitigate damage to property from the flooding effects of tsunamis and protect human life. While students design solutions associated with this natural hazard during the learning process, they naturally become curious about how tsunamis form. The OpenSciEd storyline framework is an engaging way to teach students science standards.
Climate effects of wind farm in China
Authors: Liu Yinglu
Published: February 2023

Building a new power system with new energy as the main body is a fundamental measure for energy and power sector to achieve carbon peak and carbon neutrality, and also a prerequisite for the whole economy and society to achieve the goal of "double carbon". However, how to construct a new type of power system is still a global problem, and its solution needs to rely on multidisciplinary knowledge. In this paper, a new power system analysis framework is constructed, and the structural characteristics and operation mechanism of the new power system are analyzed from the perspective of multidisciplinary comprehensive analysis. Based on this framework, we can initially diagnose various problems encountered in the construction of new power system and find possible solutions. Different actors participating in the construction of new power system can also find their own strength points in it and contribute to the security, stability and economic operation of the system.
Detecting Europa’s water plumes with the Particle Environment Package on JUICE
Authors: Huybrighs Hans , Dayton-Oxland Rowan , Galli André , Vorbuger Audrey , Föhn Martina , Wurz Peter , Mahieux Arnaud , Goldstein David , Winterhalder Thomas , Barabash Stas
Published: February 2023

The repeated eruptions of water plumes on Europa have been suggested based on Hubble observations, Keck observations and in-situ magnetic field data from Galileo (Roth et al., 2014; Sparks et al., 2016, 2017, 2019; Jia et al., 2018; Arnold et al., 2019; Paganini et al., 2019). The possibility that such plumes could transport material from Europa’s subsurface, or from water reservoirs contained in the ice layer (Vorbuger and Wurz 2021), far above the surface creates an unprecedented opportunity to sample Europa’s subsurface environment and investigate its habitability. The JUpiter ICy moon Explorer (JUICE) is scheduled to make two flybys of Europa, one over the Northern and one over the Southern hemisphere, with the closest approach at 400 km altitude.In this work we investigate the detectability of such water plumes using the Neutral and Ion Mass Spectrometer (NIM) and the ion mass spectrometer Jovian Dynamics and Composition analyser (JDC) of the Particle Environment Package (PEP) on JUICE. Using a Monte Carlo particle tracing model we simulate the density distribution of the plume and simulate the measured signature with NIM and JDC along the two JUICE flyby trajectories.Using a particle tracing model we show that H2O molecules and H2O+ ions of the plume, as well as possible minor constituents such as CO and CH4, can be detected during the JUICE flybys. We find that the plume reported by Roth et al., 2014 is the most likely to be detected, even at the lowest mass fluxes, and that the southern-hemisphere JUICE flyby has the best coverage of all the presumptive plume sources. Lowering the altitude of the southern flyby will contribute to an increased chance of detecting the presumptive plume sources, and should be prioritized over lowering the other flybys if any deltaV is available.Additionally, using a DSMC molecule and particle tracing model we investigate the effect of intermolecular collisions in the plume and demonstrate that such collisions will reduce the detectability of the plume. We also show that the JUICE flybys and the NIM characteristics will be suitable to discern the finer structure of the plume (e.g. shocks inside the plume), which will allow us to improve our understanding of the physics of Europa’s plumes.Furthermore, we also investigate the separability of the plume from Europa’s asymmetric sputtered and sublimated water atmosphere and discuss the influence of the instrument pointing and operations on the plume detectability. We find that NIM’s operational constraints are not critical in terms of detecting H2O molecules of a plume.
Multi-temporal UAS surveys for reconstructing soil water content of ploughland plots through multispectral and thermal infrared imagery
Authors: Bertalan László , Pataki Angelika , Nagy Loránd Attila , Négyesi Gábor , Szabó Szilárd
Published: February 2023

Soil water content (SWC) estimation is a crucial issue of agricultural production, and its mapping is an important task. We aimed to study the efficacy of UAS-based thermal (TH) and multispectral (MS) cameras in SWC mapping.The study area for the analysis is situated at NE-Hungary near the town of Tépe. the plot is a part of a larger area of intensive agriculture, where the arable crop at the year of surveys was maize. The experimental AOI was set to a maximum size of 200 x 200 meters due to the time-demand and limitations of the multi-sensor surveys. On the plot 3 major soil types are found meanwhile relative relief differences are also notable. Soil samples were collected at the time of surveys to measure the reference SWC rates in laboratory conditions using the gravimetric method.The aerial mapping tasks were carried out using a DJI Matrice M210 payloads: 1) Micasense RedEdge-MX Dual, 2) Zenmuse XT2. High resolution DEM of the initial surface were mapped by a DJI Matrice M210 RTK v2 + a Zenmuse X7 lens. All imagery were processed in Pix4D Mapper. Machine Learning algorithms were then utilized to model the relationship between reflectance values, land surface temperature and the reference SWC values.Our surveys were dedicated to a sensitivity analysis on the different settings of Pix4D regarding the downscaling to different pixel resolution of the multispectral data and spectral reflectance calibration too. We have analyzed the differences on the SWC modeling accuracies on the different soil types and relief conditions to develop a more robust estimation for precision drainage designs.-----------The research is supported by the NKFI K138079 project.
Characteristics of the George V and Tasman Transform Fault systems, South-East Indian Ridge, and implications for mantle dynamics.
Authors: Jbara Rim , Briais Anne , Ruellan Etienne , Ceuleneer Georges , Maia Marcia
Published: February 2023

The George V and Tasman Transform Fault Systems (TFS) are major, right-stepping offsets of the South-East Indian Ridge between 140°E and 148°E. The George V TFS (~140°E) has an offset of about 300 km, and the Tasman TFS (~148°E) an offset of about 600 km. These TFS have multiple shear zones with intra-transform ridge segments (ITRS), mostly unmapped yet. We present the results of the analysis of geophysical and petrological data collected during the STORM cruise (South Tasmania Ocean Ridge and Mantle), completed with global data sets including satellite-derived gravity and bathymetry, and earthquake distribution. The swath bathymetry data cover some parts of the shear zones and only a few of ITRSs. They reveal a complex interaction between tectonic processes at the plate boundary and near-axis volcanic activity along and across the transform faults. In both the George V and Tasman TFS the western ITRS are shallower than the eastern ones, and they appear to receive a lot more magma supply. These western ITRS display off-axis volcanism observed on swath bathymetry or suspected from free-air gravity anomaly highs. In both TFS also, the western shear zone consists of two segments separated by a tectonic massif which we interpret to represent a push-up resulting from transpression along the transform. The mechanism involved in generating the transpression is a lengthening of the western ITRS to the west due to its high magma supply, leading to an overlap between the ITRS and the ridge segment immediately to the west of the TFS, that is in a mechanism similar to the processes currently uplifting the mylonitic massif along the St. Paul TF in the Equatorial Atlantic. The bathymetric and backscatter maps of the western George V TFS also reveal a series of recent off-axis oblique volcanic ridges. Rocks dredged on one of these ridges consist of picrites (i.e. basalts rich in olivine phenocrysts). These observations suggest that both TFS are not magma starved like many mid-ocean ridge transforms, but are the locus of significant primitive melt supply. Such an unexpected production of high-Mg melt might be related to the presence of a mantle thermal anomaly beneath the easternmost SEIR, the result of regional extension following clockwise rotations of the spreading direction, and/or to a western flow of mantle across the TFS. Some of the ITRS actually appeared after changes in the Australia-Antarctic plate motion.
Rapid Estimation of Disaster Losses by Physics-based Simulation for the M6.8 Luding Earthquake on September 5, 2022
Authors: Wang Wenqiang , Zhang Zhenguo
Published: February 2023

An M6.8 earthquake occurred in Luding, Sichuan province, China on September 5, 2022. Since towns and villages in the earthquake-stricken area are densely populated, the earthquake caused severe fatalities and economic losses. Rapid estimation of earthquake intensity and disaster losses is significantly important for post-earthquake emergency rescue, scientific anti-seismic deployment, and the reduction of casualties and financial losses. Therefore, we make a preliminary rapid estimation of the earthquake intensity and disaster losses in the aftermath of the Luding earthquake. The seismic intensity represents the distribution of earthquake disasters and the degree of ground damages and can be directly converted from the peak acceleration velocity (PGV) map. To obtain a reliable PGV distribution map of this earthquake, we combined the finite-fault model constrained by seismic observations, with the complex three-dimensional (3D) geological environment and topographical features to perform strong ground motion simulation. Then, we compared the consistency between the simulated ground motion waveforms and observations, indicating the plausibility and reliability of simulations. In addition, we transformed the PGV simulation results into intensity and obtained a physics-based map of the intensity distribution of the Luding earthquake. The maximum simulated intensity of this earthquake is IX, which is consistent with the maximum intensity determined from the post-earthquake field survey. Based on the simulated seismic intensity map of the Luding earthquake and the earthquake disaster loss estimation model, we rapidly estimated the death and economic losses caused by this earthquake. The estimation results show that the death toll caused by this earthquake is most probably in the range of 50-300, with a mathematic expectation of 89 The government should launch a Level II earthquake emergency response plan. The economic losses are likely to be in the range of 10-100 billion RMB, with a mathematical expectation of 23.205 billion RMB. Such seismic intensity simulations and rapid estimation of disaster losses are expected to provide a preliminary scientific reference for governments to carry out the targeted deployment of emergency rescue and post-disaster reconstruction.
Recent trends in air-sea CO2 fluxes and ocean acidification in the Indian Ocean
Authors: Lachkar Zouhair , Mehari Michael , De Verneil Alain
Published: February 2023

Recent observations and modeling evidence indicate that the Arabian Sea (AS) is a net source of carbon to the atmosphere, whereas the Bay of Bengal (BoB) and the southern Indian Ocean (SIO) act as net carbon sinks. Yet, the inter-annual variability modulating the air-sea CO2 fluxes in the Indian Ocean, as well as their long-term trends, remains poorly understood. Furthermore, while the rising atmospheric concentration of CO2 is causing surface ocean pH to drop globally, little is known about local and regional acidification trends in the Indian Ocean. Here, we simulate the evolution of air-sea CO2 fluxes and reconstruct the progression of ocean acidification in the Indian Ocean from 1980 through 2018 using an eddy-resolving ocean biogeochemical model forced with observation-based winds and heat and freshwater fluxes. Additionally, using a set of sensitivity simulations that vary in terms of physical forcing we disentangle the contributions of climate variability and rising atmospheric CO2 concentrations to long-term trends in air-sea CO2 fluxes and acidification. Our analysis reveals a strong variability in the air-sea CO2 fluxes and pH on a multitude of timescales ranging from the intra-seasonal to the decadal. Furthermore, a relatively fast progression of ocean acidification is simulated in the SIO, as well as in the Arabian/Persian Gulf and locally in the BoB. Our analysis indicates that in addition to the increasing anthropogenic CO2 concentrations in the atmosphere, wind variability - and more prominently- the recent fast surface warming of the Indian Ocean have substantially modulated trends in air-sea CO2 fluxes and acidification at local and regional scales.
Enhanced Weathering of Olivine in Rivers for Carbon Dioxide Removal
Authors: Rønning Jakob , Campbell James S. , Renforth Phil , Löscher Carolin
Published: February 2023

Climate change continues to have escalating effects worldwide. Multiple solutions are needed, one of which is carbon dioxide removal (CDR), where CO2 is removed directly from the atmosphere.One approach to CDR is ocean alkalinity enhancement (OAE), whereby finely ground alkaline minerals are added to the ocean, increasing pH and total alkalinity and enhancing the ocean’s ability to draw down CO2 from the air. This effect also helps counter ocean acidification, a phenomenon problematic to marine biodiversity and biogeochemistry.Here a similar process is investigated but using rivers or fjords settings instead of the coasts. Rivers are proposed to be used as conveyors of finely crushed olivine (10-30 μm) mixed in river water. The goal is for the river to have higher alkalinity and pH before entering the chosen ocean region.In this work, a closed mesoscale laboratory flume is used to study the feasibility of treating three different conditions, river, fjord, or saltwater, with finely crushed olivine, for alksalisation and CO2 absorption.During the experiments, we examined weathering of olivine (details on physical and chemical composition and mineralogy needed) in flowing freshwater, brackish water, and saltwater with a flow rate of 1.25 -1.4 m3/s and the solids-to-liquid ratio of 0,00015 kg. Preliminary results indicate that freshwater is an optimal candidate as a conveyor. Furthermore, using rivers as one of the long-term solutions as an output of alkaline and pH-rich water to targeted regions is suitable.
Variations in Summer Extreme High-temperature Events over Northern Asia and the Possible Mechanisms
Authors: Hong Haixu
Published: February 2023

In this study, the variations in the extreme high-temperature event (EHE) over Northern Asia (NA) and the associated possible mechanisms are explored. On an interdecadal timescale, NA EHE frequency experienced a significant interdecadal increase around the mid-1990s, which could be associated with the phase shift of the Atlantic Multidecadal Oscillation. On an interannual timescale, the first two empirical orthogonal function modes of the NA EHE frequency exhibit meridional dipole pattern (EOF1) and diagonal tripolar pattern (EOF2), respectively. Further analysis reveals that the EOF1 mode is related to the Polar-Eurasian teleconnection pattern (POL), while the EOF2 mode is associated with North Atlantic Oscillation (NAO) and Pacific-Japan/East Asia-Pacific pattern (PJ/EAP). The fitted EHE frequency based on the atmospheric factors (POL, NAO and PJ/EAP) can explain the interannual variation in the regionally averaged EHE frequency by 33.8%. Furthermore, three anomalous sea surface temperature (SST) patterns over the North Atlantic-Mediterranean Sea region and around the Maritime Continent are associated with the two EHE modes by intensifying the pronounced atmospheric teleconnections. Analysis on the simulation of five models in the Atmospheric Model Intercomparison Project experiment further confirms the impact of the pronounced SST patterns on the POL, NAO and PJ/EAP. From a synoptic perspective, the atmospheric patterns responsible for the NA EHE are investigated. By applying a hybrid regionalization approach to the daily maximum temperature, three subregions of NA can be identified: western NA, central NA, and southeastern NA. To better understand the mechanism for the formation of EHE in each subregion of NA, the EHE-related synoptic circulation patterns over each subregion are further categorized into two types. These six synoptic circulation patterns influence the NA EHE occurrence through different radiation and advection processes. From the forecasting perspective, six wave train patterns are explored as the precursors of the six synoptic circulation patterns, separately. These wave train patterns appear over the upstream regions of NA subregions with at least three-day lead, and provide potential forecasting information for the NA EHEs. The results may deepen our understanding of the NA EHE formation and provide information for the prediction and forecast of NA EHE.  
Characteristics and Drivers of Marine Heatwaves in the Western Equatorial Indian Ocean
Authors: Qi Ruisi , Zhang Ying , Du Yan , Feng Ming
Published: February 2023

The spatio-temporal characteristics of the interannual variability and long-term trend of the marine heatwaves (MHWs) and related dynamic mechanisms in the western equatorial Indian Ocean (WEIO) are investigated using satellite observations. A prominent MHW hot spot is found in a region of the WEIO (48°E-54°E, 2°S-2°N), with a mean MHWs' intensity, duration, and frequency of 1.54°C, 13.33 days, and 1.97 times, respectively. MHWs in the hot spot region have significant interannual variability after removing the long-term trend, associated with Indo-Pacific major climate modes. In 1982/1983, 1983/1984, 1987/1988, 1997/1998, 2006/2007, 2009/2010, 2011/2012, 2012/2013, 2014/2015, 2015/2016, and 2019/2020, the MHWs occurred with longer duration, higher frequency, and more total days. These years correspond to a positive Indian Ocean Dipole, or an El Niño event, or both. The occurrence of MHWs accompanied by anomalous positive sea surface height suggests that oceanic planetary wave processes modulate MHWs in the WEIO. Westward-propagating downwelling equatorial Rossby waves triggered by anomalous equatorial easterly winds drive the convergence of warm upper-ocean water and weaken the upwelling of cool subsurface water, which favor anomalously warm sea surface temperature (SST) and the occurrence of MHWs. In addition, the westward-propagating off-equatorial downwelling Rossby waves in the southern tropical Indian Ocean also affect MHWs in the WEIO through the propagation and reflection of waves. The annual MHW frequency, duration, and total days in the hot spot region increase up to 1.56 times, 4.95 days, and 31.72 days per decade, respectively, related to the significant increase in mean SST under global warming.
National scale agricultural development dynamics under socio-political drivers in Saudi Arabia since 199
Authors: Li Ting , López Valencia Oliver , Johansen Kasper , McCabe Matthew
Published: February 2023

Driven in large part by policy initiatives designed to increase food security and realized via the construction of thousands of center-pivot irrigation fields since the 1970s, agriculture development in Saudi Arabia has undergone tremendous changes. However, little is known about the accurate number, acreage, and the changing dynamics of the fields. To bridge the knowledge gap between the political drivers and in-field response, we leveraged a hybrid machine learning framework by implementing Density-Based Spatial Clustering of Applications with Noise, Convolutional Neural Networks, and Spectral Clustering in a stepwise manner to delineate the center-pivot fields on a national scale in Saudi Arabia using historical Landsat imagery since 1990. The framework achieved producer's and user's accuracies larger than  83.7% and 90.2%, respectively, when assessed against 28,000 manually delineated fields collected from different regions and periods. We explored multi-decadal dynamics of the agricultural development in Saudi Arabia by quantifying the number, acreage, and size distribution of center-pivot fields, along with the first and last detection year of the fields since 1990. The agricultural development in Saudi Arabia experienced four stages, including an initialization stage before 1990, a contraction stage from 1990 to 2010, an expansion stage from 2010 to 2016, and an ongoing contraction stage since 2016. Most of the fields predated 1990, representing over 8,800 km2 in that year, as a result of the policy initiatives to stimulate wheat production, promoting Saudi Arabia as the sixth largest exporter of wheat in the 1980s. A decreasing trend was observed from 1990 to 2010, with an average of 8,011 km2 of fields detected during those two decades, which was a response to the policy initiative implemented to phase-out wheat after 1990. As a consequence of planting fodder crops to promote the dairy industry, the number and extent of fields increased rapidly from 2010 to 2015 and reached its peak in 2016, with 33,961 fields representing 9,400 km2. Agricultural extent has seen a continuous decline since 2016 to a level lower than 1990 values in 2020. This decline has been related to sustainable policy initiatives implemented for the Saudi Vision 2030. There is some evidence of an uptick in 2021 — also observed in an ongoing analysis for 2022 — which might be in response to global influences, such as the COVID-19 pandemic and the more recent conflict in the Ukraine, which has disrupted the international supply of agricultural products. The results provide a historical account of agricultural activity throughout the Kingdom and provide a basis for informed decision-making on sustainable irrigation and agricultural practices, helping to better protect and manage the nation's threatened groundwater resources, and providing insights into the resilience and elasticity of the Saudi Arabian food system to global perturbations.
Mohr-Coulomb yield curve and non-normal flow rule for sea ice viscous-plastic models
Authors: Ringeisen Damien , Tremblay Bruno , Lemieux Jean-François , Losch Martin
Published: February 2023

Deformation in sea ice takes the shape of narrow lines of high deformation, called the Linear Kinematic Features or LKFs. The distribution of intersection angles between LKFs indicates that the yield curve of sea ice is closer to the shape of a Mohr-Coulomb criterion than the commonly used elliptical yield curve, and that the flow rule of sea ice is most probably not normal to the yield curve. Thus, having Mohr-Coulomb yield curves in sea ice viscous-plastic models could improve the orientation and localization of LKFs in high-resolution sea ice models. In this work, we define multiple implementations of the Mohr-Coulomb yield criterion with different flow rules and test them in uniaxial compressive tests. We observe that the intersection angles are not the same as we expect from theory and previous experiments with the elliptical yield curve. To further the investigation, we define new rheologies with different yield curves and plastic potentials to study the effect of non-normal flow rules with different yield curve shapes, with the goal to finally be able to define a Mohr-Coulomb yield curve and flow rule that accurately models the creation of LKFs and their intersection angles.
Modelling soil erosion focusing on event-size occurrences under global change in a vineyard catchment
Authors: Ciampalini Rossano , Pastor Amandine , Huard Frédéric , Follain Stéphane , Licciardello Feliciana , Crabit Armand , Raclot Damien
Published: February 2023

Soil erosion is a balance between forces acting to detach and transport sediment and those resisting, such as soil cohesion or protection of vegetation cover. The amount of eroded particles is proportional to the acting forces, but the feedback, as is widely acknowledged, has a non-linear behaviour. Moreover, most of the erosion is concentrated in the strongest events, as evidenced by many authors.Here, in a long-term simulation, we investigate the occurrence of the size of the erosion events in a vineyard catchment area. We analysed around 700 rainfall events over 20 years  from two climate series (historical 1985-2005, and and future 2040-2060), and four contrasted land use and management scenarios.The results confirmed that the erosion is driven by a limited number of strong events with an increment in future series due to an increase in frequency of the more severe rainfall events. We observed that: 1) Size of erosion events VS return time exhibit different logarithmic trends in each LU scenario; 2) Long-term erosion series show that the few major erosion phases are due to a limited number of events, the most severe; 3) The concentration of erosion events towards the highest values is more pronounced in intensified landscape indicating more reactive erosion than in protected landscapes.This suggests that controlling the state of intensification of a landscape (i.e. intensified or preserved) can mitigate soil erosion even if climate change tends to increase erosion rates.
S-wave isotropic and radially anisotropic velocity structure in the Western Pacific inferred from partitioned waveform inversion
Authors: Park Ji-hoon , Chang Sung-joon , Witek Michael , Lee Sang-Mook , Kim YoungHee , Utada Hisashi , Shiobara Hajime , Isse Takehi , Takeuchi Nozomu , Sugioka Hiroko
Published: February 2023

In the Western Pacific, there are unique geologic/tectonic features such as oldest oceanic crust in the Pacific, seamount chains derived from the Caroline hotspot, the Ontong-Java plateau which is the largest large igneous province, and complex plate boundaries between major and microplates. Investigation of isotropic and anisotropic velocity structure for this region is essential to our understanding of those unique features aforementioned. We estimate an S-wave isotropic and radially anisotropic velocity model beneath the Western Pacific by applying partitioned waveform inversion to three-component seismograms collected from the Incorporated Research Institutions for Seismology Data Managing Center, the Oldest-1 Array deployed in 2018-2019 by a joint Korean-Japan research team, and the Ocean Hemisphere network Project (OJP, NM, and SSP networks). We nonlinearly invert three-component waveforms from 17,038 raypaths (Mw > 5.5) with a 3-D reference model consisting of Crust1.0 and AK135 and resulting constraints are used for iterative least-squares inversion to build an S-velocity model. Our isotropic Vs model shows low-Vs anomalies at ~40 km depth beneath the Ontong-Java Plateau indicating a thick crust, at ~200 km depth beneath the Woodlark spreading center and Caroline seamount chain and at ~600 km depth beneath the center of the Eauripik rise. High-Vs anomalies are observed beneath the center of the Ontong-Java Plateau at 40-150 km depth and at ~50 km depth beneath the West Philippine basin, the Parece-Vela basin, and the Caroline basin. Overall positive radial anisotropy anomalies are observed in the Western Pacific, but the contrast of anisotropy was found in the Pacific plate, Philippine Sea plate, and Caroline plate at ~50 km depth. Negative radial anisotropy anomalies found in the Perace-Vela basin at ~30 km depth, and strong positive anisotropy anomalies are observed at the northern boundary of the Ontong-Java Plateau and beneath the Sorol trough and Caroline seamount chain.
Towards a representation of complex ecosystems in the ORCHIDEE Land Surface Model
Authors: Alléon Julien , Bonan Gordon , Ghattas Josefine , Lansoe Anne-Sofie , Luyssaert Sebastiaan , Ogée Jérôme , Ottlé Catherine , Peylin Philippe , Polcher Jan , Tuzet Andrée , Vuichard Nicolas
Published: February 2023

Complex ecosystems, such as mixed forests or savannahs, are poorly represented in Land Surface Models (LSM). Those models mainly use simple and efficient representations such as the “big leaf” model for the energy budget in order to minimize time calculation. However, this approach prevents them from modelling more complex processes such as intra-canopy climate or competition for water between different vegetation strata which are highly important processes in order to understand the behavior and the responses of complex and mixed ecosystems in a changing climate. Although some ecosystem-specific models start to represent the 3D structure of complex ecosystems, including competition for light, water and nutrient between species and vertical / horizontal organization, these approaches are still too complex to be fully included in global LSM. However, first steps can be made towards this direction by representing the exchanges and interactions of biophysical fluxes such as water, carbon and energy. This study proposes some first steps towards this direction. We refined the computation of the energy and water transfers in the soil –plant – atmosphere continuum, working both on the horizontal and vertical heterogeneity. On the water transfers side, we implemented the soil-plant-atmosphere continuum model developed by Tuzet et al. (2017) which introduces a proper representation of the water flow inside the vegetation and a stronger coupling between plant water status and stomatal conductance. On the energy budget point of view, we implemented the multi-layer energy budget developed by Ryder et al. (2016) which represents the exchanges and turbulent transport of light and energy within a canopy. Finally, those two works being adapted for site-level modelling, we introduced a sub-grid heterogeneity representation of the energy and water budget in order to implement those developments for global applications. The study focuses on the two first developments which are firstly tested over several forest sites where intra-canopy gradients of humidity and temperature have been measured. A model inter-comparison between two LSM who have developed a vertical multi-layer energy budget, ORCHIDEE and CLM5 (Lawrence et al. (2019)), and the forest model MuSICA (Ogée et al. (2003)) allowed to highlight some of the model strengths and weaknesses. Finally, the expected improvements for complex ecosystems modelling and future developments in ORCHIDEE based on those representations will be presented.
Paleoelevation Reconstruction of Subduction Zones in Eastern Pacific Continental Margins Quantitatively with Igneous Geochemistry
Authors: Liu Bingxi , Williams Simon , Zhao Guochun , Yu Shan , Jian Dongchuan
Published: February 2023

Reconstructing past episodes of mountain building from the geological rock record is one of the main challenges for unravelling the ancient physical geography of Earth’s surface. Mountains and mountain ranges, often situated at convergent plate margins, play a pivotal role in many fields of the Earth, climate, and biological sciences. Established methods for quantifying past elevations traditionally relied on sedimentary rocks, but in recent years, alternative approaches have emerged on the basis that geochemical signatures of magmatic rocks formed in convergent settings correlate with crustal thickness or elevation. These correlations allow for empirical relations of igneous whole-rock ratios such as La/Yb and Sr/Y with Moho depth for modern convergent settings, which can then be used to estimate ancient crustal thickness or paleoelevation. Since a relatively large number of igneous samples are available for pre-Cenozoic times compared to other paleoelevation proxies, these methods have the potential to allow quantitative mapping of past topographic change for times where existing maps are largely based on a qualitative approach.Here, we investigate the application of paleoelevation estimates derived from geochemistry using the Pacific margin of South America as a case study. We investigate their consistency with independent indicators of past elevations such as stratigraphy, stable isotopes, fossils etc. for Cenozoic samples along the Andean margin. For older times, we compare the estimated paleoelevations with other aspects of the geological record, as well as equivalent values from global paleogeography models widely used in climate modelling studies, to evaluate the extent to which these models are consistent with the igneous geochemical proxies. We derive paleoelevation estimates according to different data filtering schemes, showing that a major consequence of the choice of geochemistry filter is the number of data points left after the filtering. We find that the igneous geochemical proxies yield elevations broadly consistent with traditional results for the Cenozoic, though our results do not resolve some of the rapid uplifts recorded by other proxies. In deeper time, we show that igneous geochemistry quantifies changes in elevation related to documented phases of crustal thickening and thinning, and is thus likely to allow improvements to existing maps of paleotopography. 
Combined hydroacoustic and optical mapping for marine munition dumpsite characterisation and DMM mass calculations
Authors: Kampmeier Mareike , Greinert Jens
Published: February 2023

After the Second World War, large quantities of conventional munition were dumped in the German Baltic Sea. Most of the munition is concentrated in coastal munition dumpsites in water depths between 10 and 25 meters (Kampmeier et al., 2020). The toxic explosives they contain and their degradation products pose a threat to the local marine environment, as shown by Beck et al. (2021), Strehse, et al. (2020) and Schuster et al. (2021).Despite these alarming news, the precise number of discarded munitions material (DMM) and its role in complex marine ecosystems is not yet fully explored. For the development of future remediation plans, the number, types and locations of the munitions needs to be known and an ecological and geological characterisation of the sites performed. Multibeam echosounding in combination with photo mapping are key-methods not only for spatial munition mass calculations, but also for detailed marine habitat mapping. High-resolution 400 - 700 kHz MBES data provide bathymetric maps with decimetre resolution on which DMM hotspots can be identified. AUV-based photo mapping can subsequently be used at certain locations to produce highly detailed photo mosaics and digital elevation models  in millimetre resolution. The combination of both mapping methods is used to compare two DMM hotspots within the German Baltic Sea, Kolberger Heide in Kiel Bay and Pelzerhaken in Luebeck Bay. We will show prominent differences in terms of type and number of munitions, corrosion and deposition status and local habitat. The goal is to transfer such details to the larger-scale MBES data in order to provide dumpsite- habitat characterisations and make DMM mass calculations within the Baltic Sea more robust.
A global 30m bifurcating river network
Authors: Wortmann Michel , Slater Louise , Hawker Laurence , Neal Jeffrey
Published: February 2023

River bifurcations, multi-thread rivers and artificial channels are not commonly included in global river networks, as they defy the gravity flow assumption elevation-derived networks are based on (e.g. HydroSheds, MERIT Hydro). Yet, these natural and artificial river divergences are important features of the global river drainage system and matter greatly at local to regional scales for various riverine risk assessments. For example, large river deltas are often highly populated regions, in part because of the rivers’ many distributaries. Representing these diverging flows in global river networks will greatly improve the accuracy of many river-based geoscience applications, such as flood forecasting, water availability and quality simulations, or riverine habitat mapping. We developed a vector-based, global river network that not only represents the tributary components of the global drainage network but also the distributary ones, including multi-thread rivers, canals and delta distributaries. We achieve this by merging a 30m, Landsat-based river mask with elevation-generated streams to ensure a homogeneous drainage density outside of the river mask (rivers narrower than approx. 30m). Crucially, this is the first global hydrography derived from a global 30m digital terrain model (FABDEM, based on Copernicus DEM) that shows greater accuracy over the traditionally used SRTM derivatives. OpenStreetMap river centrelines are used to increase the accuracy of the network outside of the river mask. After vectorisation and pruning, directionality is assigned by a combination of elevation, flow angle and continuity approaches. The new global network and its attributes are validated using gauging stations, reference river networks and randomised manual checks. The new network represents ~18 million km of streams and rivers with drainage areas greater than 50km2 and includes ~58 thousand. bifurcations in rivers wider than 30m. The hydrography includes vector river segments, sub-1km reaches and catchments as well as 30m flow direction and accumulation rasters. With the advent of hyper-resolution modelling in the geosciences at the regional and global scale, we expect this river network to be relevant to a broad range of applications in flood protection, hydrology, ecology, fluvial geomorphology and others. The network has been developed as part of the NERC-funded EvoFlood project and will be used to improve global flood models.
About the possibility of using AMATERAS data to check the detection of dangerous asteroids
Authors: Zhumabayev Beibit , Vassilyev Ivan
Published: February 2023

Asteroids approaching the Earth from the direction of the Sun and may pose a danger to the Earth are detected either too late or are not detected at all by optical observations. They can be detected using passive radar, using the radio emission of the Sun as a probing signal [2,3]. It is most convenient to use Venus, Mercury and the Moon as calibration objects when working out the method of detecting small celestial bodies, since their position relative to the Sun is easy to calculate, and their sizes are well known. If the control bodies deviate from the direction of the Sun by 2 degrees, the delay of the signals reflected from Mercury, Venus and the Moon will be 484, 118 and 0.2 ms, respectively. Due to the relatively small delay values of the reflected signals, it is impossible to use most of the available solar radio telescopes with an integration time of 1 to 10 seconds to implement this method. The radio telescope of the AMATERAS project [1], capable of receiving signals of less than 0.7 SFU with an integration time of 10 ms, is suitable for receiving and isolating reflected signals. The beam width of the radiation pattern of the AMATERAS radio spectropolarimeter is about 4 degrees at a frequency of 150 MHz, which allows receiving signals simultaneously directly from the Sun and reflected from the Moon during periods of solar eclipses. With the passive location of Mercury and Venus, it is most expedient to use type I radio flashes with a duration of less than 1 second as a probing signal. When locating the Moon, it is more convenient to use type III radio flashes, during which the radiation frequency changes at a speed of up to 20 MHz/ s (2 kHz in 10 ms). For ten years of observations of the Sun, a large amount of data has been accumulated on the AMATERAS system, including during solar eclipses, which allows us to work out algorithms for direction finding of small celestial bodies approaching the Earth from the Sun in the post-processing mode.References[1] Iwai K., Tsuchiya F., Morioka A., Misawa H. IPRT/AMATERAS: A new metric spectrum observation system for solar radio bursts // Solar Phys. 2012. V. 277. P. 447–457. DOI: 10.1007/s11207-011-9919-y.[2] Vassilyev I., Zhumabayev B. On the possibility of using the Orbita radio polygon for radar detection of asteroids // Satellite monitoring of geodynamic processes and space weather. – Almaty, 2020 – pp. 133-138.[3] Pavelyev A., Gubenko V., Matyugov S., Zakharov A., Yakovlev O. Perspectives of the bistatic radar and occultation studying of the Venus and planetary atmospheres and surfaces EGU General Assembly 2013 EGU2013-10289, 07-10 April 2013.