bluuebunny/crossref_metadata_2025 huggingface dataset:
Scientific Highlights from ROMIC
Authors: Lübken Franz-Josef
Published: February 2023

The German Federal Ministry of Education and Research (Bundesministerium für Bildung und Forschung, BMBF) has launched a research initiative in 2013/2014 called ROMIC (Role of the Middle Atmosphere in Climate). The second phase of this project extends until 2024. The aim of ROMIC is to improve our understanding of long term variations in the stratosphere, mesosphere, and lower thermosphere and to investigate their potential role forclimate changes in the troposphere. This includes to study coupling mechanisms between various layers and the relative importance of anthropogenic and natural forcing, e.\ g., by the Sun. Scientists at a total of 13 research institutes in Germany are involved and cover a large range of experimental and theoretical topics relevant for ROMIC. Most projects are linked to international activities and cooperations. Some scientific highlightsfrom the research projects within ROMIC will be presented.
AI Assisted Data Selection of Laser Altimeter Observations
Authors: Stenzel Oliver , Maes Lukas , Hilchenbach Martin
Published: February 2023

Laser altimeters create large amounts of data that often have to be preprocessed and checked before further use. The BepiColombo mission to Mercury is set to arrive in December 2025 and observations with the BepiColombo Laser Altimeter (BELA, (Benkhoff et al., 2010; Thomas et al., 2021)) will start during the following spring. These measurements are planned to be used to derive information about the tides of Mercury (Thor et al., 2020). Careful assessment, selection, and filtering on the raw data is needed to extract the small tidal signal. Until the BELA data becomes available artificial data and records from other missions have to be used to study the data selection strategy. We present our work on MESSENGER Laser Altimeter (MLA, (Cavanaugh et al., 2007)) using a convolutional neural network to sort observations on an orbit by orbit basis into different classes. The already existing neural network (Stenzel and Hilchenbach, 2021; Stenzel, Thor and Hilchenbach, 2021) is tuned and a new test data set is created. 
Benkhoff, J. et al. (2010) ‘BepiColombo—Comprehensive exploration of Mercury: Mission overview and science goals’, Planetary and Space Science, 58(1), pp. 2–20. Available at: https://doi.org/10.1016/j.pss.2009.09.020.
Cavanaugh, J.F. et al. (2007) ‘The Mercury Laser Altimeter Instrument for the MESSENGER Mission’, Space Science Reviews, 131(1), pp. 451–479. Available at: https://doi.org/10.1007/s11214-007-9273-4.
Stenzel, O. and Hilchenbach, M. (2021) ‘Towards machine learning assisted error identification in orbital laser altimetry for tides derivation’, pp. EPSC2021-688. Available at: https://doi.org/10.5194/espc2021-688.
Stenzel, O., Thor, R. and Hilchenbach, M. (2021) ‘Error identification in orbital laser altimeter data by machine learning’, pp. EGU21-14749. Available at: https://doi.org/10.5194/egusphere-egu21-14749.
Thomas, N. et al. (2021) ‘The BepiColombo Laser Altimeter’, Space Science Reviews, 217(1), p. 25. Available at: https://doi.org/10.1007/s11214-021-00794-y.
Thor, R.N. et al. (2020) ‘Prospects for measuring Mercury’s tidal Love number h2 with the BepiColombo Laser Altimeter’, Astronomy & Astrophysics, 633, p. A85. Available at: https://doi.org/10.1051/0004-6361/201936517.
 
Fe-Si-gel like injections in banded iron formations of the Musselwhite Mine (Canada)
Authors: Hawemann Friedrich , Passchier Cees , Biczok John
Published: February 2023

A sample of banded iron formation from a drill core from the Musselwhite Gold Mine, Ontario, Canada, shows millimeter-wide opaque veins at a low angle to the foliation with perpendicular offshoots. The veins are non-crystalline, structureless and chemically homogeneous, with oxide weight percentages of 35 % FeO, 40 % SiO2, 5 % MnO, 5 % MgO and 1 % CaO. The remaining ca. 15 % might be attributed to water content. Despite the water, the composition is very similar to the bulk rock composition, consisting mainly of grunerite and quartz. The overall geometry of the veins resembles the appearance of a pseudotachylyte with injection veins, partly sharp boundaries, and clasts of the host rock. However, no other indicative observations such as flow banding, quenched margins or corrosion of clasts can be made. Instead, the vein is overgrown by euhedral quartz, nucleating from wall rock quartz crystals. Some of the material is emplaced in a calcite vein where the calcite seems to be fragmented. EBSD orientation data show that the fragments have the same orientation as calcite crystals remaining attached to the wall rock. Calcite crystals are therefore not displaced, but rather dissolved or replaced by the vein filling material, but without leaving a chemical signature. We therefore favor an Fe-Si rich gel-like injection origin of the veins. It remains unclear, how the gel was produced and how it is mechanically possible to inject such a gel into a solid rock and replace calcite.
IASI Carbon Monoxide Global and Regional Trends over the period [2008 - 2022]
Authors: Sinnathamby Selviga , Safieddine Sarah , Viatte Camille , Hadji-Lazaro Juliette , George Maya , Clerbaux Cathy
Published: February 2023

Carbon monoxide (CO) is a key atmospheric pollutant that is closely monitored for its role intropospheric chemistry as a modulator of the oxidizing capacity of the atmosphere. It is mainlyemitted into the atmosphere during combustion processes linked to anthropogenic activities(heating, industry, transport) and during biomass combustion (natural fires or burning of agriculturalwaste).Since 2007, three IASI (Infrared Atmospheric Sounding interferometer) instruments have beensuccessively embarked on board of the polar-orbiting meteorological satellites Metop-A, -B and -C.They provide a global and daily coverage of CO concentrations in the atmosphere, with two dailyoverpasses (at 9:30 am and 9:30 pm local time). In February 2022, EUMETSAT reprocessed the wholeIASI CO dataset , providing a homogeneous record of CO, since the beginning of the mission.In this study, and for the first time, we use this 15-years of continuous and homogenized dataset toanalyze the evolution of daytime CO concentrations from January 2008 to December 2022. TheTheil-Sen method is applied on the deseasonalized dataset in order to compute the slope of thetrend. The p-value of Sen’s Slope is determined by using the Mann-Kendall test.Here, we analyze the evolution of CO concentrations on a global and regional scale, and show theevolution of CO concentrations in each hemisphere and in specific regions of the world that aresensitive to biomass fires (Central Africa, South America) and anthropogenic emissions (South andEast Asia, Europe and North America). The results are compared with the documented trends inemission inventories.
Stress and strain patterns related to the inversion of the High Atlas aborted rift
Authors: Skikra Hamza , Amrouch Khalid , Soulaimani Abderrahmane , Amarir Salih
Published: February 2023

The Moroccan High Atlas is an Alpine fold belt formed by the structural inversion of Mesozoic rift basins during the Late Cretaceous-Cenozoic. The involvement of mantle-related thermal mechanisms is anticipated to account for the anomalously elevated orogen and surrounding plateaus and basins. In the range’s Western portion, the Marrakech High Atlas displays the most pronounced basement exposure at the range scale. Recent studies highlighted the role of thick-skinned tectonics thrusting and folding during the basin inversion. Although several works brought considerable insights into the actual understanding of the High Atlas structural evolution, there is still an ambiguity regarding the kinematics, paleostresses, and tectonic regime associated with the basin inversion. In the present work, we examine the paleostresses history of the High Atlas fold belt through analyses of mesostructures i.e. striated faults planes, micro-shear fractures/veins, tensile fractures/veins, stylolites and mesoscale folds, in the northern and southern borders of the Marrakech High Atlas. The aim of this work is to illustrate the tectonic complexity of orgenic belts developed in an intracontinental setting far from the plates’ collision boundaries.
Emergence of extreme precipitation statistics from the properties of convective cells
Authors: Marra Francesco , Dallan Eleonora , Morin Efrat , Armon Moshe
Published: February 2023

The statistics of extreme precipitation over a location of interest are crucial for designing hydraulic structures and mitigating extreme events impact. These statistics emerge from (i) the presence of different storm types, (ii) the different intensity of storms of a given type, (iii) the spatial variability of storms during their life-cycle, combined with (iv) the advection of storms across the domain. Explicit separation of these components could help us establish links between atmospheric dynamics (i.e., the occurrence and frequency of different types of storms) and thermodynamics (i.e., the properties of different storm types) on one side, and the emerging statistics of extremes. Here, we make a first step in this direction by focusing on a semi-arid region in the southeastern Mediterranean in which precipitation is almost solely related to convective processes, minimizing the effect of point (i).We use very-high-resolution (60 m x 60 m, 1 min) weather radar observations to track convective cells during 11 storms that occurred over 2 years (>1200 cells). We mimic rain gauge observation of the tracked cells by sampling the rainfall fields at random locations and we alter advection by applying synthetic velocities to the Lagrangian fields of the cells. This allows us to isolate the impacts of (ii) storm intensity, and (iv) advection. Then, we generate sets of synthetic cells with analogous properties (peak intensity, area, velocity) and different profiles to examine the impact of (iii) spatial variability.We find that the spatial sampling of convective cells occurred during the 11 storms explains most of the variability of extreme precipitation in the region. The extremes emerging from this sampling are well described by Weibull tails. Return levels estimated from the 11 storms using a non-asymptotic extreme value method are comparable to the ones derived from 25 years of rain gauge observations (error in the 100-year return levels <15%). We discuss the sensitivity of extreme return levels to changes in properties and velocities of the convective cells.
Carbon and water fluxes of the boreal evergreen needleleaf forest biome constrained by assimilating ecosystem carbonyl sulfide flux observations
Authors: Abadie Camille , Maignan Fabienne , Remaud Marine , Kohonen Kukka-Maaria , Sun Wu , Kooijmans Linda , Vesala Timo , Seibt Ulli , Raoult Nina , Bastrikov Vladislav , Belviso Sauveur , Peylin Philippe
Published: February 2023

Boreal forests absorb a significant amount of atmospheric CO2 through gross primary production (GPP), representing about 20% of the global GPP. However, direct observations of GPP over the whole boreal region are not available as plant photosynthetic rate cannot be measured at scales larger than the leaf scale. At large scales, Land Surface Models (LSMs) can simulate GPP but the lack of direct GPP measurements makes it challenging to evaluate and improve the GPP representation in LSMs. In addition, boreal forests are highly sensitive to environmental changes, impacting gas exchanges and leading to high uncertainties in GPP estimates simulated by LSMs or obtained from data driven methods. Carbonyl sulfide (COS) has emerged as a promising proxy to infer GPP estimates or to better constrain GPP representation in LSMs. Because COS is absorbed by vegetation following the same diffusion pathway as CO2 during photosynthesis and not emitted back to the atmosphere, implementing a mechanistic representation of vegetation COS uptake in LSMs allows using COS data to constrain GPP representation. In this study, we performed ecosystem COS flux and GPP assimilations to constrain the COS and GPP related parameters in the ORCHIDEE LSM. We focused on Hyytiälä forest, where the longest time-series of ecosystem COS flux measurements was reported. We found that assimilating ecosystem COS fluxes increases the estimated net ecosystem COS uptake by 14%. However, a persistent underestimation of the ecosystem COS flux seasonal amplitude after data assimilation points towards structural errors in the COS model, possibly related to COS internal conductance representation. In comparison with an assimilation of GPP only, adding ecosystem COS flux assimilation leads to a stronger reduction in the stomatal conductance, highlighting the potential of COS to inform stomatal diffusion. Consequently, including COS data in the assimilations also impacts the resulting latent heat flux and water use efficiency. Finally, we scaled up this assimilation framework to the boreal region and found that the joint assimilation of COS and GPP fluxes increased the modeled vegetation COS uptake up to 18%, but not the GPP budget. This contrasts with previous inversion studies that simultaneously increase vegetation COS uptake and GPP budgets based on a linear relationship relating the two. 
How consistent are citizens in their observation of temporary streams?
Authors: Scheller Mirjam , van Meerveld Ilja , Blanco Sara , Seibert Jan
Published: February 2023

Half of the global river network dries up from time to time. However, these so-called temporary streams are not represented well in traditional gauging networks. One reason is the difficulty in measuring zero flows. Therefore, new approaches, such as low-cost sensors and citizen science, have been developed in the past few years. CrowdWater is such a citizen science project, in which citizens can submit observations of the state of temporary streams with the help of a smartphone app. The flow state of the stream is assessed visually and assigned to one of the following six classes: dry streambed, wet/damp streambed, isolated pools, standing water, trickling water, and flowing.To determine the consistency of observations by different citizens, we asked questions regarding the flow state to more than 1200 people, who passed by temporary streams of various sizes in Switzerland and Germany. The survey consisted of 19 multiple-choice questions (with 14 being yes/no questions), three rating scale questions, two open-ended questions and five demographic questions, and was available in German and English. Most participants were interested in the topic and happy to participate. We estimate that about 80% of the people we approached participated in the survey.Over 90% of the participants were native German speakers. When the expert assessment of the flow state was dry streambed, isolated pools or flowing water multiple surveys (4-6) could be done for up to four streams. Other states (standing water and trickling water) were assessed at only one stream. The surveys covered all six flow state classes: dry streambed: 4 times with a total of 244 participants; wet/damp streambed: 3 times with 179 participants; isolated pools: 5 times with 265 participants; standing water: 3 times with 177 participants; trickling water: 2 times with 106 participants; flowing: 6 times with 297 participants.The answers of the participants were consistent for the driest and wettest states (dry streambed and flowing water) but differed for the in-between states. For example, half of the participants at one stream chose the wet streambed category, while the other half decided on standing water. This suggests that visual assessments of flow states for multiple classes are more complicated than could be assumed initially, but still give additional information beyond the flowing or dry categories. Above all, it provides information for streams that otherwise would be unmonitored.
The Impact of Solar Energetic Particles at Mars’ radiation environment: A synergistic approach combining measurements and Modeling efforts
Authors: Guo Jingnan
Published: February 2023

Radiation is one of the most important risks to deep space exploration programs such as manned missions to the Moon and Mars. In preparation for such programs, it requires a thorough understanding of interplanetary space weather conditions and a timely forecast of their potential effects as a baseline for the development of mitigation strategies.  Radiation damage in space comes mainly from two sources, Galactic Cosmic Rays (GCRs) and Solar Energetic Particles (SEPs). In particular, intense SEP events could result in very high doses in a short time period that may exceed the threshold to induce deterministic radiation effects and to result in severe damages to humans and equipment leading to the failure of the entire mission. SEP events with radiation hazards, despite of being rather infrequent and sporadic, are however very difficult to forecast and remain as a major challenge for space weather studies in preparation for future deep space and Mars missions. Specifically speaking, the SEP radiation reaching an astronaut on a Mars may be completely different from of that detected at (or predicted for) Earth’s vicinity, including the SEP onset time, spectra evolution, radiation intensity etc. This is due to (1) the different location of Mars and connectivity to the acceleration source which allow it to have difference access to the SEP population, and (2) the different planetary environment which modifies the energy and composition of the particles due to the interactions of primary particles with the atmosphere/regolith and the generation of secondaries. The synergistic analysis and modeling of these two processes are particularly important to understand and eventually forecast SEPs and their radiation effects on Mars in preparation for mitigating their potential hazardous effects.  We also emphasize the utmost importance of utilizing multi-spacecraft particle measurements at Mars and also other heliospheric locations to better understand such extreme events and their radiation effects for future deep space explorers.
Global occurrence of continuing currents in lightning and lightning-ignited wildfires predicted for the next century
Authors: Pérez-Invernón Francisco J. , Gordillo-Vázquez Francisco J. , Huntrieser Heidi , Jöckel Patrick
Published: February 2023

Lightning flashes can produce a discharge in which a continuing electrical current flows for more than 40 ms. Such flashes have been proposed to be the main precursors of lightning-ignited wildfires.In this work, we used lightning measurements provided by the Geostationary Lightning Mapper (GLM) over the continental United States of America during the summer of 2018 to confirm the role of lightning with continuing currents in the ignition of wildfires. We investigated projections in the occurrence of lightning with continuing currents and in the meteorological conditions that favor wildfires over the next century by applying a new parameterization of continuing currents based on the updraft strength. The simulations are performed by using the European Center HAMburg general circulation (ECHAM) / Modular Earth Submodel System (MESSy) Atmospheric Chemistry (EMAC) model [1]. We found a 41% increase in the occurrence of lightning with continuing currents worldwide. Increases are largest in South America, the western coast of Northern America, Central America, Australia, Southern and Eastern Asia, and Europe, while only regional variations are found in northern polar forests, where wildfires can affect permafrost soil carbon release. We obtained a possible increase in the risk of lightning-ignited fires in Europe, Eastern Asia, North America, the Western coast of South America, Central Africa and Australia. In turn, the simulations suggest a decrease in the risk of lightning-ignited wildfires in polar regions of Eurasia and North America. Finally, projections do not show any clear tendency in the Amazon rainforest during the typical fire season.[1] Pérez-Invernón, F. J., Huntrieser, H., Jöckel, P., and Gordillo-Vázquez, F. J.: A parameterization of long-continuing-current (LCC) lightning in the lightning submodel LNOX (version 3.0) of the Modular Earth Submodel System (MESSy, version 2.54), Geosci. Model Dev., 15, 1545–1565, https://doi.org/10.5194/gmd-15-1545-2022, 2022.
The electrostatic electron beam-plasma instabilities and nonlinear radio emissions. Theory vs. PIC simulations
Authors: Lazar Marian , Lopez Rodrigo A. , Shaaban Shaaban M. , Poedts Stefaan
Published: February 2023

Electrostatic wave instabilities induced by energetic electron beams are believed to be at the origin of radio emissions reported by the observations of interplanetary shocks and solar coronal sources. We revisit the electron beam-plasma configurations found susceptible to nonlinear radio (electromagnetic) emissions, but which led to contradictory outcomes both in the linear theory and especially in the numerical simulations. The results of a new dispersion and stability analysis are presented, in which the electron populations are modeled both with standard Maxwellian velocity distributions and with Kappa distributions revealed by in situ measurements. We thus describe not only the exact nature of these electrostatic fluctuations (e.g., electron beam modes, modified Langmuir waves, or electron acoustic waves), but also a series of characteristics that help to distinguish them in observations. The particle-in-cell simulations confirm the predictions of the linear theory, and show for the first time how the nonlinear radio emissions are modified due to the Kappa distributions of the electron populations.
CNES/CLS IGS Analysis Center 2022/2023 Activities
Authors: Loyer Sylvain , Mezerette Adrien , Saquet Eléonore , Baños-Garcia Adrian , Santamaria Gomez Alvaro , Mercier Flavien , Perosanz Felix
Published: February 2023

We present in this contribution the main aspects of efforts done at the CNES/CLS Analysis Center in 2022-2023. We recall the main changes associated with the adoption of the IG20/IGS20.atx standards relying on the recently released International Terrestrial Reference Frame (ITRF2020) and following our participation to the third IGS reprocessing campaign (REPRO3).  We also increased our participation to IGS with the delivering of rapid and ultra-rapid products: the quality and specificities of these products (orbit, clocks and erp) are presented together with their availability and some details on the associated processing chain. Finally, we focus on the preliminary results of the processing of the satellites of the Beidou constellation that will be included soon in our products.
Interplay between fluid flow and rock deformation in an exhumed hydrothermal fault-vein network
Authors: Masoch Simone , Fondriest Michele , Gomila Rodrigo , Pennacchioni Giorgio , Cembrano José , Di Toro Giulio
Published: February 2023

Faults can act as conduits for the migration of hydrothermal fluids in the crust, affecting its mechanical behaviour and possibly leading to earthquake swarm activity. To date, there are still few constraints from the geological record on how fault-vein networks develop through time in high fluid-flux tectonic settings. Here, we describe small displacement (<1.5 m) epidote-rich fault-vein networks cutting granitoids in the exhumed Bolfin Fault Zone (Atacama Fault System, Chile). The epidote-rich sheared veins show lineated slickensides with scattered orientations and occur at the intersections with subsidiary structures in the fault damage zone. FEG-SEM cathodoluminescence (CL) reveals that magmatic quartz close to the sheared epidote-rich veins is affected by (i) thin (< 10 µm) interlaced deformation lamellae and (ii) a network of CL-dark quartz epitaxial veinlets sharply crosscutting the lamellae. EBSD maps of the deformed quartz indicate minor lattice distortion associated with the lamellae and an orientation nearly orthogonal to the c-axis. These deformation features disappear moving away into the host rock. The epidote-rich sheared veins (i) include clasts of magmatic quartz with both the deformation lamellae and the healed veinlets and (ii) show cyclic events of extensional-to-hybrid veining and localized shearing. We propose that the microstructures preserved in the quartz next to the sheared veins (i.e. deformation lamellae and epitaxial veinlets) record the high-strain rate loading associated with dynamic crack propagation and rapid micro-fracture sealing. On the other hand, the cyclic dilation and shearing within the epidote-rich veins is interpreted as the expression of a highly connected fault-vein network dominated by pore pressure oscillations leading to seismic swarm activity.
Landscapes on the edge: solving the river intermittency puzzle
Authors: McLeod Jonah S. , Whittaker Alexander C. , Bell Rebecca E. , Hampson Gary J. , Watkins Stephen E. , Brooke Sam A. S. , Rezwan Nahin , Hook Joel , Zondervan Jesse R.
Published: February 2023

Water and sediment transport in rivers are not uniform through time. In perennial rivers, sediment may be in motion for much of the year. However, intermittent rivers only transport bedload material during the most significant flow events, therefore changes in precipitation patterns have a large impact on these sensitive systems. Understanding intermittency is thus a key challenge in the Earth Sciences due to the vulnerability of landscapes in a changing climate. Here, we generate new constraints on modern fluvial intermittency factors based on field measurements in the Gulf of Corinth, Greece, including hydraulic geometry, sediment grain size and well-constrained Holocene accumulation rates into a closed basin. Results reveal that these rivers are extremely intermittent, requiring only 1 - 5 hours of active bedload transport per year in order to fulfil their annual bedload sediment budgets. Historical data reinforce these results, suggesting that the channels draining into the Gulf are only active in large, infrequent storms associated with rainfall rates > 50 mm/d; this hydroclimate is typical of large areas of Mediterranean landscape. Furthermore, climate models predict precipitation extremes (i.e., storminess) will increase across Europe. Therefore, as the threshold of sediment transport is surpassed more frequently, we predict annual sediment budgets will increase significantly by the year 2100. As storminess increases, source-to-sink dynamics in intermittent river systems across the globe are likely to be the most impacted by environmental change in the near future.
Multi-model downscaling simulations of regional climate and air quality in China
Authors: Cui Mengshi
Published: February 2023

In this study, a multi-model ensemble of regional climate and air quality coupling model system was established to evaluate current climate and air pollution in China during 2010-2014. Meteorological initial and boundary conditions were obtained from the multi earth system models used in the Coupled Model Intercomparison Project Phase 6 (CMIP6) with a dynamical downscaling method and the National Centers for Environmental Prediction Final Analysis (NCEP-FNL) reanalysis data. These downscaling data under the historical scenario and FNL data were applied to driven the Weather Research and Forecasting model coupled to Chemistry (WRF-Chem) to simulate current climate and air quality. A comprehensive evaluation of the current five years was conducted against the ground-level meteorological and chemical observations. The performances for the 2 m temperature were very well and consistently overestimated the wind speed at 10 m by 0.8~1.2 m/s. PM2.5 and ozone concentrations were underestimated by the downscaling data driven simulations compared with the FNL data. The model performance was relatively well and can be used to study the impacts of climate change on China's future air quality and pollution events in the context of carbon neutrality and clean air, which may shed light on policy formulation for medium and long-term air quality management and climate change alleviation.
Global physiography dynamics controled the Phanerozoic diversification of the biosphere
Authors: Husson Laurent , Salles Tristan , Lorcery Manon , Hadler Boggiani Beatriz
Published: February 2023

 
The contrasted diversification of marine and terrestrial life remains enigmatic. The monotonic expansion of species on continents started later in the early Phanerozoic than in the marine realm, where instead the number of genera waxed and waned. Only a comprehensive evaluation of the changes in the physical environment can provide a unified theory for the long-term pattern of evolution of life on Earth. We developed a numerical model to reconstruct the evolution of the physiography at global scale and high resolution over the entire Phanerozoic eon, accounting for plate tectonics and climatic forcings.
Our results point at landscape dynamics as a limiting factor both in lands and oceans, mostly by erosion and sediment transport. Marine diversity was strongly limited by the oscillating bulk riverine sedimentary fluxes that provide nutrients, while the expansion of land plants was hampered until widespread endorheic basins resurfaced continents with a sedimentary cover that facilitated the development of soil-dependent rooted plants. In both realms, landscape dynamics determine the carrying capacity of the environment.
Gaussian Processes for vegetation traits global mapping
Authors: Martínez-Ferrer Laura , Moreno-Martínez Álvaro , Muñoz-Marí Jordi , Meyer Hanna , Ludwig Marvin , Camps-Valls Gustau
Published: February 2023

Machine learning algorithms have become widely used for geospatial applications, including spatial mapping and upscaling ecological variables and traits. Multivariate splines, random forests, and neural networks have been widely used to upscale a few sparse measurements to larger areas. Machine learning models, however, cannot offer reliable predictions in out-of-the-sample areas, which is often the case in such applications [1,2]. In [3], an area of applicability is proposed as an extrapolation index based on the minimum distance to the training data in the multidimensional predictor space with predictors being weighted by their respective importance in the model. We propose Gaussian Processes (GPs) to derive such extrapolation indicator [4].  A GP is a popular method in machine learning and multivariate statistics for regression problems. It provides a probabilistic description of the predictive function, so one can derive both predictive mean and variance for the predictions on new data. We here suggest using the predictive variance as an indicator for extrapolation and show the relation with a customized dissimilarity index computed that follows the Area of Applicability methodology proposed in [3]. We show the relation and in some cases the generalization in a set of controlled synthetic experiments and for vegetation traits global mapping using remote sensing, meteorological variables and the (huge yet sparse and biased) TRY database. This relation opens the door to a more sound way of identifying and characterizing extrapolation regimes through GPs in geospatial and upscaling applications.References[1] Deep learning for the Earth Sciences: A comprehensive approach to remote sensing, climate science and geosciences. Gustau Camps-Valls, Devis Tuia, Xiao Xiang Zhu, Markus Reichstein (Editors). Wiley & Sons 2021[2] Perspective on Deep Learning for Earth Sciences. Camps-Valls, Gustau. Generalization with Deep Learning: for Improvement on Sensing Capability, World Scientific Pub Co Inc 2021[3] Meyer, H., & Pebesma, E. (2021). Predicting into unknown space? Estimating the area of applicability of spatial prediction models. Methods in Ecology and Evolution, 12, 1620–1633. https://doi.org/10.1111/2041-210X.13650[4] A Survey on Gaussian Processes for Earth Observation Data Analysis: A Comprehensive Investigation. Camps-Valls, G. and Verrelst, J. and Muñoz-Marí, J. and Laparra, V. and Mateo-Jiménez, F. and Gómez-Dans, J. IEEE Geoscience and Remote Sensing Magazine 2
Sensitivity of simulated mesoscale convective systems over East Asia to the treatment of convection in a high-resolution GCM
Authors: Li Puxi , Muetzelfeldt Mark , Schiemann Reinhard , Chen Haoming , Li Jian , Furtado Kalli , Zhuang Moran
Published: February 2023

Mesoscale convective systems (MCSs) downstream of the Tibetan Plateau (TP) exhibit unique precipitation features. These MCSs can have damaging impacts and there is a critical need for improving the representation of MCSs in numerical models. However, most global climate models are typically run at resolutions that are too coarse to reasonably resolve MCSs, and it is still unclear how well higher-resolution global models can reproduce the precipitation characteristics of MCSs. In this study, the sensitivity of MCSs simulated by a global high resolution (~10km), atmosphere-only climate model to different treatments of convection (with and without parametrized convection, and a hybrid representation of convection) have been investigated. The results show that explicit convection (i.e., non-parameterized) can better reproduce the observed pattern of MCS precipitation over the East Asian Summer Monsoon (EASM) region. In general, explicit convection better simulates the diurnal variability of MCSs over the eastern China, and is able to represent the distinctive diurnal variations of MCS precipitation over complex terrain particularly well, such as the eastern TP and the complex terrain of central-northern China. It is shown that explicit convection is better at simulating the timing of initiation and subsequent propagating features of the MCS, resulting in better diurnal variations and further a better spatial pattern of summer mean MCS precipitation. All three experiments simulate MCS rainfall areas which are notably smaller than those in observations, but with much stronger rainfall intensities, implying that these biases in simulated MCS morphological characteristics are not sensitive to the different treatment of convection.
Calcite TLM and LSJ07: two natural reference materials for micro-beam U-Pb geochronology and C, O isotope ratio measurements
Authors: Wu Shitou , Yang Yueheng , Romer Rolf , Roberts Nick M W , Lan Zhongwu
Published: February 2023

U-Pb geochronology of calcite using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) is an emerging method, with potential applications to a vast array of geological issues. Accurate LA-ICP-MS calcite U-Pb dating requires matrix-matched RMs for the correction of instrumental mass bias of Pb/U ratios. Several materials are currently being used as RMs, including WC-1, Duff Brown Tank, ASH-15, JT, and AHX-1A. In this study, we will give a brief introduction of LA-ICP-MS lab at IGGCAS for carbonate U-Pb dating. Meanwhile we further characterized two calcite reference materials for micro-beam U-Pb geochronology and and C, O isotope ratio measurements. LA-ICP-MS multiple spot analyses (> 400) at different regions of materials reveal that calcite TLM and LSJ07 are homogeneous for the U-Pb age with 220.72 +/-0.98 Ma and 26.54+/-0.41 Ma respectively. SIMS multiple spot analyses (> 100) reveals calcite TLM is homogeneous for the O isotope ratio at mm special resolution. MAT 253 gives a bulk result of δ18O =-14.20 ‰. LA-MC-ICP-MS multiple spot analyses (> 200) reveals calcite TLM and LSJ07 are homogeneous for the C and O isotope ratio at mm special resolution. MAT 253 gives bulk results of δ13C =-1.53 ‰ andδ13C =-0.33 ‰ for TLM and LSJ07 respectively. These two materials represent a useful addition to the currently distributed WC-1, Duff Brown Tank, ASH-15, JT, and AHX-1A for micro-analytical techniques of U-Pb geochronology and C, O isotope ratio measurements.
Improving the detection of global NOx emissions from shipping in S5P/TROPOMI data
Authors: Latsch Miriam , Richter Andreas , Burrows John P.
Published: February 2023

Ships are important emission sources of nitrogen oxides (NOx), which are relevant pollutants in the atmosphere affecting the environment and human health. Global shipping plays a big role in transporting goods around the world. For decades, some of the busiest shipping lanes have been tracked by satellites from space. With TROPOMI aboard the Sentinel 5-Precursor (S5P), the potential for detecting shipping emissions has increased due to its low noise and high spatial resolution of 5.5 x 3.5 km2. Previous studies have shown that even individual ship plumes can be identified from TROPOMI data.In this study, we use different filtering methods to identify on a global scale as many shipping emission signals as possible from the TROPOMI data. One important aspect is to focus on finding real shipping signals and avoiding inadvertently interpreting a priori information. The aim of this study is to contribute to the progress of satellite remote sensing of shipping emissions and to better understand air pollution caused by the shipping sector and their effect on the environment.
Impact of evolutionary populations on soil organic matter characteristics
Authors: Rumpel Cornelia , Vedere Charlotte , Visioli Giovanna , Gazza Laura , Galaverna Gianni
Published: February 2023

In Mediterranean areas, agricultural systems have to adapt to an environment presenting few water resources with severe drought events, which are expected to increase in frequency and intensity due to global warming. Therefore, these regions are particularly exposed to climate change and need to implement solutions in order to maintain food production.            Our objective is to assess the benefits of innovative cropping systems capable to face these constraints. Evolutionary population are mixtures of plants of the same species presenting a high degree of crop genetic diversity needing lower inputs while allowing higher buffering capacities to adapt environmental stress like water shortage. In this study, we investigated the influence that these plants can have on organic matter quality and dynamics and hypothesised that the abilities of the crop to face drought can participate at increasing soil carbon storage in soil.      We conducted a field experiment with five different evolutionary populations of wheat, i.e. a bread wheat (Monnalisa), an einkorn wheat (Norberto) and 2 evolutionary populations (Furat-Li Rosi, Furat-Floriddia and BIO2), cultivated following four other plants species (Wheat, Pea, Cickpea or Clover) on two different sites in Italy presenting contrasted conditions (hot-summer Mediterranean climate in Roma and humid subtropical climate in Parma). Bulk soil and rhizosphere soils were sampled and C, N contents as well as organic matter functional groups using Mid Infrared Spectroscopy (MIRS) were assessed.   We observed that the infrared signatures differed between our two sites and depending on the previous cropping species. Evolutionary population of wheat showed different signatures than durum and bread wheat. Our results demonstrate that evolutionary population in particular pedoclimatic conditions can influence the fate of soil organic matter.
Non-linear Rainfall Trend Extraction Using Hybrid Empirical Mode Decomposition And Singular Spectrum Analysis
Authors: Shejule Priya , Pekkat Dr. Sreeja
Published: February 2023

Identification and precise quantification of rainfall trend are crucial for researchers to understand the variations in rainfall over a longer period of time. On a global scale, climate change is influencing the intensity and frequency of rainfall, leading to extreme rainfall events. The expeditious and systematic consideration of rainfall changes is important in this context. In the given study, EMD-SSA, a hybrid data-adaptive multivariate multiscale method based on empirical mode decomposition (EMD) and singular spectrum analysis (SSA), is proposed to extract the non-linear trend present in the rainfall series. At the initial stage, EMD is applied to decompose the observed rainfall series into several intrinsic mode functions (IMFs) of different frequencies depicting trends and oscillatory patterns. Periodogram analysis of each IMF is performed by Lomb-Scargle spectral analysis to identify the important periodic signals and their period. These periods are considered suitable input (embedding dimension) to the SSA. The rainfall data is collected on a daily scale for the region of Mumbai, India, from NASA’s Prediction of Worldwide Energy Resource (POWER) archive from 1981–2020. The non-linear trend present in the rainfall is estimated by the EMD, SSA, and EMD-SSA methods. From the analysis, an increasing rainfall trend is observed in the Mumbai city, indicating more rainfall events in the future. Finally, the study suggests that a hybrid EMD-SSA is better than standalone EMD and SSA approach. In the future, the proposed EMD-SSA can also be applied to understand the variabilities in rainfall pattern with respect to the climate indices.  
Impact of radon exposures on non cancer outcomes and future perspectives
Authors: Zilli Vieira Carolina L , Koutrakis Petros
Published: February 2023

Radon is a naturally occurring radioactive gas formed from the decay of primordial radionuclides (Uranium and Thorium) in the Earth's crust. It infiltrates into homes from soil, water, and construction materials. Indoor radon is one of the leading cause of lung cancer. Our recent studies have showed short- and middle-term exposures to indoor radon are also related to increased risk of cardiovascular, pregnancy and respiratory morbidity and mortality. These findings bring a new direction for radon exposures and health outcomes studies.  In this overview, we will present our most recent studies on radon exposures and non-cancer outcomes, describing from biological mechanisms to future directions for public health policies.
Earthquake Nucleation: The formation of rupture fronts and the influence of local conditions
Authors: gvirtzman shahar , fineberg Jay
Published: February 2023

In recent years, there has been important progress in the experimental study of earthquakes (‘laboratory earthquakes’). Much has been learned about the character and dynamics of rupture fronts propagating along a frictional interface. These fronts are the vehicle with which the contacts composing a frictional interface break, therefore enabling slip. These fronts were shown to be identical to shear cracks, whose propagation characteristics are fully described by the framework of fracture mechanics.However, the formation of these fronts - the nucleation process - is not yet fully understood. This process is not included in the fracture mechanics framework, which describes only cracks that are above the critical (Griffith) length needed for propagation, and does not provide us an explanation on how a small defect grows and reaches this critical point. In laboratory experiments, obtaining a detailed description of nucleation is a challenge, due to its unpredictable nature.We use an experimental system in which the real contact area between 2 PMMA blocks is continuously imaged into a fast camera to record the dynamics at the onset of frictional motion and to monitor the propagation of the rupture fronts. In order to overcome the difficulties of the unpredictable nucleation process, a unique experimental technique is used to dictate the nucleation location, thus enabling the direct measurements of the nucleation time and local stresses at the nucleation point. In these controlled experiments, the dynamics of the nucleation process during the slow expansion of a nucleation patch are recorded in detail, as well as the transition to the fast propagation of the newly formed front.We find that the expansion of the nucleation patch is qualitatively different than the propagation of the fully formed rupture front. It occurs at extremely slow and constant velocities, and it is 2D in nature. Some of the features of this expansion, like self-similar evolution and timescales that are stress-dependent, are general. However, the details of this process are governed by the local conditions at the nucleation region. Due to the slow rates of expansion, local variations in the surface toughness (the ‘fracture energy’) can influence characteristics such as the exact nucleation point, the shape of the patch, and the stress threshold that is needed for nucleation to occur.As nucleation is not described by the usual frameworks that are used to explain rupture propagation, understanding the driving mechanism of it is of fundamental importance to questions ranging from earthquake nucleation and prediction to processes governing material failure. We propose a possible mechanism for this process and discuss it.
Potential shift of rainy seasons’ onset and cessation under climate change scenarios in West Africa
Authors: Weber Torsten , Gbode Imoleayo E. , Coulibaly Amadou , Abel Daniel , Ziegler Karin , Zoungrana Jean-Bosco B. , Traore Seydou B. , Paeth Heiko
Published: February 2023

Information on the onset and cessation of rainy seasons is an important prerequisite for planning the sowing of crops in West Africa. A late onset, but also too early cessation of a rainy season, has a direct impact on plant growth and thus on the crop yield in the region. However, onset and cessation dates of rainy seasons can change under future climatic conditions. Therefore, this information is key for stakeholders and decision-makers to mainstream climate change into agricultural activities and policies for better adaptation in the region.To obtain information on the onset and cessation of rainy seasons on a regional scale under future climate change, Regional Climate Models (RCMs) are applied to dynamically downscale global climate projections generated by Earth System Models (ESMs). Therefore, regional climate projections provide more detailed information due to the higher spatial resolution compared to the climate projections generated by ESMs.The study will show initial results on the onset and cessation of rainy seasons in West Africa under two emission scenarios using the Representative Concentration Pathways (RCPs) 2.6 and 8.5 for the end of the century (2071-2100 vs. 1981-2010). The regional climate projections are taken from the Coordinated Output for Regional Evaluations (CORE) embedded in the WCRP Coordinated Regional Climate Downscaling Experiment (CORDEX) for Africa with a spatial resolution of about 25 km. In this initiative, three different RCMs (REMO2015, RegCM4-7, and CCLM5-0-15) were applied to perform the downscaling process.
Predictable healing rates in near-surface materials after earthquake damage in Chile
Authors: Illien Luc , Turowski Jens M. , Sens-Schönfelder Christoph , Berenfeld Clement , Hovius Niels
Published: February 2023

Earthquakes introduce long-lasting transient mechanical damage in the subsurface that can take years to recover to a new elastic steady-state. The associated transient perturbation of the elastic moduli can cause postseismic hazards such as enhanced landsliding.  This dynamics is linked to relaxation, a phenomenon observed in a wide class of materials after straining perturbations. In this study, we analyze the successive effect of two large earthquakes (the 2017 Mw7.7 Tocopilla and the 2014  Mw8.2 Iquique earthquakes) on ground properties through the monitoring of seismic velocity from ambient noise interferometry in the Atacama desert in Chile. The absence of rainfall in this area allows study of the mechanical state of the subsurface by limiting the potential effect of variations in groundwater content. We show that relaxation timescales are a function of the current state of the subsurface when perturbed by earthquakes, rather than ground shaking intensity. Our study highlights the predictability of earthquake damage dynamics in the Earth's near-surface and potentially other materials. We propose to reconcile this paradigm with existing physical frameworks by considering the superposition of different populations of damaged contacts. 