bluuebunny/crossref_metadata_2025 huggingface dataset:
Poleward moisture transport and its influence on precipitation in the Arctic: From case studies to long-term statistics
Authors: Lauer Melanie , Rinke Annette , Gorodetskaya Irina , Crewell Susanne
Published: March 2020

There are many factors which could contribute to the Arctic warming: feedback processes like the lapse rate and ice-albedo feedback, the increasing downward longwave radiation caused by clouds and water vapour, and the reduction of sea ice in summer that leads to absorption of solar radiation and increase in local evaporation and more clouds. But also the atmospheric moisture transport from the lower latitudes can contribute to the surface warming in high-latitudes. This poleward moisture transport is mostly accomplished by extra-tropical cyclones, with especially strong contribution by the Atmospheric Rivers (ARs). ARs are long, narrow bands of enhanced water vapour transport which are responsible for over 90% of the poleward water vapour transport in and across mid-latitudes. Furthermore, they are responsible for producing significant levels of rain and snow. In addition, the greenhouse effect of water vapour and the formation of clouds increase the downward longwave radiation which can cause a thinning and melting of Arctic sea ice and snow.

In this study, we investigate the contribution of ARs to Arctic precipitation. Firstly, we look into different case studies for which observational data from the campaigns within the Collaborative Research Center “Arctic Amplification: Climate Relevant Atmospheric and Surface Processes, and Feedback Mechanisms (AC)3” exist. The data include enhanced observations at/around Svalbard performed during the ACLOUD and the AFLUX campaigns.

Previous studies have shown that ARs reaching into the Arctic have different origins, including the Atlantic and the Pacific pathways and also Siberia. Here we examine which pathway is more common and which one transports more moisture into the Arctic for these case studies by using existing AR catalogues from global and polar-specific algorithms. Furthermore, the variability of precipitation influences the surface mass and energy balance of polar sea ice and ice sheets. Therefore, we will analyse the influence of ARs on precipitation in terms of frequency, intensity, and type of precipitation (rain or snow) for the different case studies. For this purpose, we will use reanalyses and observational data for the water vapour transport, total precipitation, rain and snow profiles.The occurrence of ARs and its influence on precipitation will be extended from case studies to the long-term statistics (for at least 10 years).
Cloud regimes and associated MJO variability over the Maritime Continent in austral summer
Authors: Zhao Zijie , Vincent Claire , Lane Todd
Published: March 2020

In this study, a new technique to determine distinct cloud regimes and their variation in space and time is proposed, evaluated, and applied to two satellite products over the Maritime Continent (MC). Compared to previous methods, the method presented here allows different types of cloud to co-exist in the same grid at the same time, giving rise to physically explainable and spatially continuous patterns in cloud regimes. Similar results generated by ISCCP – H and Himawari 8 data suggests that the method is robust. The 4 cloud regimes determined using this method are associated with shallow, mid-level, deep convective and high level clouds respectively. The analysis shows that he MJO–induced variation in total cloud fraction is dominated by day-time high–level clouds, while the diurnal MJO variability is mostly demonstrated by low–level cumulus. Spatial and temporal rainfall variability over the MC during austral summer is dominated by high–level clouds, while most local signatures and land–sea differences are attributed to deep convective clouds. Using an artificial neural network, the cloud patterns over the MC can be classified into nine categories, largely dominated by the MJO-phase. Active MJO activity is shown by systematic propagation around the cloud categories, with one category associated with the inactive MJO phase. The inhomogenous propagation of the MJO can partially be revealed in the generated patterns, which can be physically explained by the enhanced/suppressed convection over the Indian Ocean. This work has implications for understanding the MJO-scale variation in precipitation and diabatic heating associated with different cloud regimes, and its representation in mesoscale and climate scale modelling systems.
A Space-Time Modeling Framework for Streamflow Extremes
Authors: Ossandon Alvaro , Rajagopalan Balaji , Kleiber William
Published: March 2020

Streamflow extremes, especially, summer seasonal streamflow in monsoon climate makes a significant contribution to the reliability of water resources and the health of ecology. The summer extreme precipitation and streamflow also cause severe floods resulting in loss of life and property. Large scale climate drivers impart strong spatial and temporal variability in the flow extremes, which needs to be modeled for use in efficient management of resources. To this end, we developed a space-time model to capture the variability of –summer season 3-day maximum streamflow. In this, the extremes at each station are assumed to be distributed as Generalized Extreme Value (GEV) distribution with non-stationary parameters. Thus, the parameters are modeled as a linear function of suitable covariates – typically, large scale climate variables and regional mean precipitation. In addition, the spatial dependence of the extremes is modeled via a Gaussian copula. The parameters of the nonstationary GEV at each location are estimated via maximum likelihood, whereas those of the Copula are estimated via the Inversion of Kendall’s tau estimator method. Ensembles of streamflow in time are based on the temporal varying covariates and from the Copula are generated, consequently, capturing the spatial and temporal variability and the attendant uncertainty. Furthermore, various return level can also be obtained from these simulations. The model is demonstrated by application to 3-day maximum summer streamflow in a representative basin from two different monsoonal climate – India and Southwest U.S. In addition to comparing the performance of the median of the simulations with the historic observations, we also compare the number of stations that exceed a specific level- say, 75th percentile which indicates the spatial performance. The model validation indicates that the model is able to capture the space-time variability, furthermore, it captures the variability in wet and dry years, consistent with observations. This framework can be applied to generate ensembles of at several lead times – week to seasonal, to provide risks of various levels of streamflow. This will be of immense use in water resources, agriculture and flood management and planning.
Ultra-relativistic electron’s pitch angle distribution narrowing associated with the solar wind density enhancement
Authors: Xie Lun , Xiong Ying , Fu Suiyan , Pu Zuyin
Published: March 2020

Electron pitch angle distribution (PAD) is a critical parameter in the study of the dynamics of the radiation belt electrons. It is well known that solar wind pressure has an impact on the PAD of the geomagnetically trapped electrons. Using the Van Allen Probes' data, we find that the MeV electron PAD at 4.5<L*<5.5 became narrowing (PAD is mainly concentrated at 90 degree) for over three days during a prolonged enhancement of the solar wind number density on November 27-30, 2015. During that period, the EMIC waves are observed by Van Allen Probe-A and ground stations on the afternoon and dusk MLTs at L>4. Meanwile, the precipitations of tens of keV protons and MeV electrons are observed by POES satellites. Additionally, there is a growing dip in electron phase space density at L*~5, indicating a local loss caused by the wave-particle interaction. The narrowing of the electron PAD is energy-dependent and the PAD is more anisotropic for electrons with higher energy, which is consistent with the wave-particle interaction with the EMIC waves. Furthermore, previous studies have shown that high solar wind density can lead to a hot and dense plasma sheet. The inward penetration of a dense plasma-sheet down to 4 Re has been confirmed by THEMIS spacecraft. We suggest that the overlap of the plasma sheet and the plasmasphere provide a favorable condition for exciting EMIC waves and the loss of small pitch angle electrons by EMIC waves can lead to the electron PAD narrowing. 

 
Complex system for earthquakes forecast using gas emission observations
Authors: Toader Victorin - Emilian , Moldovan Iren-Adelina , Ionescu Constantin , Marmureanu Alexandru , Mihai Andrei
Published: March 2020

Romanian National Institute of Earth Physics (NIEP) develops a gas emission monitoring network as part of a multidisciplinary activity. The goal is to help organizations specialized in emergency situations with short-term earthquakes forecast and information related to pollution and effects of climate change. In Romania, the important seismic area is Vrancea where there are seismic and multidisciplinary monitoring stations. The methods and monitoring solutions are general and they could be applied in any place. The main part of our system is related to CO2, CO, radon, air ionization in correlation with earth radiation, air ionization, telluric currents, ULF radio waves disturbance, magnetic field, temperature in borehole, infrasound, acoustic waves and meteorological data. The monitoring stations are located on the faults in the curvature of the Carpathian Mountains. The first step is to determine the daily, seasonal and annual evolutions of gas emissions and ionization of the air for at least one year. We are looking for time intervals during which the seismic activity was reduced to determine the normal evolutions of the measured parameters. Then we can determine the effects of active seismic periods on gas emissions. We will apply several methods of analysis and will correlate the particularities of the geological structure in which the monitoring stations are located and the position of the epicenters of earthquakes. The present results are favorable to the analysis by integrating the values measured on variable time windows according to the case. Instantaneous values also include local effects that are not related to tectonic stress. Current measurements indicate the presence of CO at certain times of the day and at certain stations. This is not possible due to tectonic stress, but may be the result of pollution in short-distance cities and air currents that spread it.

Key words: gas emission, multidisciplinary analysis, radon concentration, air ionization, multi-parametric monitoring, earthquake forecast, earthquake precursors
Updated Magnitude Scales for Mars
Authors: Böse Maren , Stähler Simon , Giardini Domenico , Ceylan Savas , Clinton John , van Driel Martin , Knapmeyer Martin , Lognonné Philippe , Banerdt Bruce
Published: March 2020

About one year after the successful deployment of the InSight (Interior exploration using Seismic Investigations, Geodesy and Heat Transport) very-broadband seismometer on the Martian surface and the identification of several hundreds of seismic events in the current InSight catalogue, we revise the pre-launch magnitude relations in Böse et al. (2018) to account for the seismic and noise characteristics observed on Mars. The data collected so far indicate that (1) marsquakes are characterized by energy between ~0.1-10Hz; (2) neither surface-wave nor secondary phase arrivals have yet been identified; and (3) a class of high-frequency events exists that are visible mainly as an increased excitation of the 2.4Hz mode. In view of these observations, we up-date scaling relations for the spectral and body-wave magnitudes, and introduce a new magnitude scale for high-frequency events. We use these relations to determine that the magnitudes of events in the current InSight catalogue range between 1.0 and 4.0.
Anoxic metabolism after the 21st century in oxygen minimum zones
Authors: Koeve Wolfgang , Landolfi Angela
Published: March 2020

Global models project a decrease of marine oxygen over the course of the 21th century. The future of marine oxygen becomes increasingly uncertain further into the future after yr 2100 , partly because ocean models differ in the way organic matter remineralisation continues under oxygen- and nitrate-free conditions. Using an Earth system model of intermediate complexity we found that under a business-as-usual CO2-emission scenario ocean deoxygenation further intensifies for several centuries until eventually ocean circulation re-establishes and marine oxygen increases again. (Oschlies et al. 2019, DOI 10.1038/s41467-019-10813-w).

In the Pacific Ocean the deoxygenation after yr 2100 goes along with the large scale loss of nitrate from oxygen minimum zones. Here we explore the impact on simulated ocean biogeochemistry of three different process formulation of anoxic metabolism, which have been used in other ocean models: (1) implicit sulphate reduction (organic matter degradation continues without oxidant), (2) no sulphidic metabolism (organic matter is not degraded under anoxic conditions), and (3) explicit sulphate reduction (with H2S as explicit model tracer). The model with explicit sulfphate reduction supports larger regional organic matter fluxed into the deep ocean and an increase in respired carbon storage, compared with the model applying implicit sulphate. We discuss the impact of anoxic metabolism on the coupling between export production and respired carbon stored in the ocean interior.
Sill-related seafloor domes in the Zhongjiannan Basin, western South China Sea
Authors: Geng Minghui , Zhang Ruwei , Song Haibin , Guan Yongxian
Published: March 2020

The magmatism activities exert significant impact in sedimentary basins as the Zhongjiannan Basin (ZJNB), western South China Sea (SCS). We have evaluated multibeam bathymetric and multichannel seismic reflection data acquired by the Guangzhou Marine Geological Survey in recent years, in order to investigate the distribution, the characteristics and the subsurface structures related to the seafloor domes found in the northeastern ZJNB. Data reveal that there are forty two domes occurring in water depths between 2312 m and 2870 m, clustered around volcanic mounds and seamounts in the study area. These domes generally show circular to elongated or irregular plan views, can reach up to 26080 m in perimeters, and the vertical reliefs are tens to hundreds of meters. They have gentler flanks with average slope values of 1.46°~7.73° and basal areas between 0.85 km2 and 42.06 km2. The seismic reflection sections reveal that domes’ formation and development are attributed to igneous intrusion events in the strata. The igneous intrusions heat surrounding organic-rich sediments and release hydrocarbons and fluids, which accumulate and uplift the overlying strata immediately above the sills and form forced folds, manifesting as domes on the seafloor. These sill-folds-dome structures provide possibility for hydrocarbon generation, migration and accumulation and have important implications for petroleum prospectivity in the ZJNB.
Crustal and upper mantle Structure Beneath the Ordos Block by Multi-scale seismic tomography
Authors: Guo Biao , Chen Jiuhui , Li Xiaoshu , Li Shuncheng
Published: March 2020

The Ordos Block located in the center of China mainland, which is one of the oldest and most stable cratons in Asia. It is contiguous to the Yinshan Block, the North China Craton, Alex Block, Yangze Block, and Northeast Tibet. Numerous geologic and geophysical studies engaged in the mechanics of the Ordos Block deformation and evolution, but the detail structure and deformation style of the Ordos Block remains uncertain due to poor geophysical data coverage. During 2013 and 2018, China Earthquake Administration developed XMLY Seismic Array in Ordos Block and adjacent area, which operated more than 1000 broadband seismic stations with an average station spacing of 35km. Using the P-wave Travel time data recorded by the array and multi-scale seismic traveltime tomography technique, we obtained a high-resolution P-wave velocity structure beneath Ordos Block. The seismic tomography algorithm employs sparsity constrains on the wavelet representation velocity model via the L1-norm regularization. This algorithm can efficiently deal with the uneven-sampled volume, and give multi-scale images of the model. Our preliminary results can be summarized as follows: 1, the crustal and upper mantle P-wave velocity structure is strongly inhomogeneous and consistent with the surface geological setting; 2, significant low-velocity anomalies exist beneath the northwestern margin of Ordos Block, which suggested that there exist upper mantle upwelling; 3, There have obvious boundary between Alex and Ordos Block along 104ºE at upper mantle;  4, Along 38ºN tectonic line, there exist different structure between south part and north part of Ordos upper mantle, the south part of Ordos show high-velocity feature and the upper mantle show low-velocity anomalies in north part of Ordos Block. This feature can be interpreted that the two parts of the Ordos Block undergone different Tectonic evolution processes.
Interseismic Deformation in the Gulf of Aqaba Inferred from GPS Measurements
Authors: Castro-Perdomo Nicolas , Viltres Renier , Masson Frédéric , Ulrich Patrice , Bernard Jean-Daniel , Dhahry Maher , Liu Shaozhuo , Alothman Abdulaziz , Zahran Hani , Mai P. Martin , Jónsson Sigurjón
Published: March 2020

The Dead Sea Transform fault forms the boundary between the Arabian plate and the Sinai-Levant subplate. Several aspects of this fault system have been extensively studied during the last century. However, the present-day kinematics and deformation along its southern end in the Gulf of Aqaba remain poorly understood. Here we present a crustal motion velocity field based on three GPS surveys conducted between 2015 and 2019 at 30 campaign sites, complemented by 12 permanent stations operating near the gulf. We constrained a pole of rotation for the Sinai-Levant subplate based on five selected stations on the Sinai Peninsula. This Euler pole predicts a left-lateral slip rate of ~4.5 mm/yr on the fault system in the gulf, consistent with earlier findings. We find that standard models of interseismic deformation, such as back-slip and screw dislocation models do not provide a reasonable constraint on fault locking depths due to limited near-fault measurements. Despite this, our results reveal a small (~1 mm/yr) but systematic left-lateral residual motion across the gulf that cannot be resolved by elastic models of strain accumulation. We further find that the orientation of these residuals agrees with modelled postseismic transient motions caused by the 1995 MW 7.2 Nuweiba earthquake in the NE and SW quadrants relative to the gulf trend. Combined, these observations suggest that postseismic deformation caused by the Nuweiba earthquake may still be ongoing. We anticipate our findings to be a starting point for future geodetic studies in the northern Red Sea region where large-scale infrastructure mega-projects, such as the NEOM city and the King Salman bridge across the gulf are being developed. Future studies would benefit from incorporating additional GPS stations on the Sinai side of the gulf, refined finite-fault models, seafloor geodetic measurements and better information about past earthquakes.
Early warning of the Pacific Decadal Oscillation phase transition using complex network analysis
Authors: Lu Zhenghui , Yuan Naiming , Ma Zhuguo , Yang Qing , Kurths Juergen
Published: March 2020

The different phases of the Pacific Decadal Oscillation (PDO) are a primary source of internal decadal climate variability which have distinct impacts on global climate and human society. However, obtaining a reliable prediction of the PDO phase transition is still challenging. Here, we employed the new technique of climate network analysis to uncover early warning signals prior to a PDO phase transition. An examination of cooperative behaviors in the PDO region revealed an enhanced signal that propagated from the western Pacific, passed through the Kuroshio extension (KE) and the subtropical oceanic frontal (STF) regions, and finally reached the northwest coast of the Americas. This signal captured all six of the PDO phase transitions from the 1890s to 2000s, with a warning time of 6.5±2.3 years in advance. It also underpinned the possible PDO phase transition at years around 2015, which may be triggered by the strong El Niño in 2014-2016.
Extraction of seasonal surface ablation zone in DALK glacier based on Landsat-8
Authors: Qu Yutong , Liu Yan
Published: March 2020

Spatio-temporal variation of snowmelt affects the Earth’s radiation budget hence serves as a proxy of climate change and global warming. Ablation zone including blue ice and wetsnow has a low surface albedo and melt water ponding ice shelf surface during summer that enhances crevasse propagation then poses a threat the stability of ice shelves. The lack of high spatial and temporal ablation product limits the in-depth exploration of the mechanism and spatio-temporal characteristics of ablation in Antarctica. Here an ablation area detection method based on the modified normalized difference water index adapted for ice (MNDWIice ) is developed to determine and characterize ablation variationsbased on Landsat-8 images of the Dalk glacier, East Antarctica, between September 2016 and March 2017.. The results showed that the Landsat-8 reflectance data can be used to extract seasonal ablation using a uniform MNDWIice threshold (0.136), and the average extraction accuracy is 81.5%, and varies between 67.7% and 94.2% in case of the thin cloud and fractional topographic shadow.The ablation area and the mean value of MNDWIice in the ablation zone show obvious seasonal spatio-temporal variation characteristics. The ablation area in the Dalk glacier appears no later than the earliest time (early September) of the observation. The earliest appearance of ablation is mainly distributed at the eastern grounding line where the terrain changes drastically. Brightness temperature and air temperature of Zhongshan Station show a strong correlation, which can be used as a mechanism analysis of the ablation zone distribution.

Key words Antarctica, Dalk glacier, ablation, MNDWIice
Evolution of deep mantle sourced carbonated melt in the mantle lithosphere
Authors: Zhang Guoliang
Published: March 2020

Deep sourced magmas play a key role in distribution of carbon in the Earth’s system. Oceanic hotspots rooted in deep mantle usually produce CO2-rich magmas. However, the association of CO2 with the origin of these magmas remains unclear. Here we report geochemical analyses of a suite of volcanic rocks from the Caroline Seamount Chain formed by the deep-rooted Caroline hotspot in the western Pacific. The most primitive magmas have depletion of SiO2 and high field strength elements and enrichment of rare earth elements that are in concert with mantle-derived primary carbonated melts. The carbonated melts show compositional variations that indicate reactive evolution within the overlying mantle lithosphere and obtained depleted components from the lithospheric mantle. The carbonated melts were de-carbonated and modified to oceanic alkali basalts by precipitation of perovskite, apatite and ilmenite that significantly decreased the concentrations of rare earth elements and high field strength elements. These magmas experienced a stage of non-reactive fractional crystallization after the reactive evolution was completed. Thus, the carbonated melts would experience two stages, reactive and un-reactive, of evolution during their transport through in thick oceanic lithospheric mantle. We suggest that the mantle lithosphere plays a key role in de-carbonation and conversion of deep-sourced carbonated melts to alkali basalts. This work was financially supported by the National Natural Science Foundation of China (91858206, 41876040).
The Dark Side of the Knowledge Graph - How Can We Make Knowledge Graphs Trustworthy?
Authors: Huber Robert , Klump Jens
Published: March 2020

“We kill people based on metadata.” (Gen. Michael V. Hayden, 2014) [1]

Over the past fifteen years, a number of persistent identifier (PID) systems have been built to help identify the stakeholders and their outputs in the research process and scholarly communication. Transparency is a fundamental principle of science, but this principle of transparency can be in conflict with the principles of the right to privacy. The development of Knowledge Graphs (KG), however, introduces completely new, and possibly unintended uses of publication metadata that require critical discussion. In particular, when personal data, as is linked with ORCID identifiers, are used and linked with research artefacts and personal information, KGs allow identifying personal as well as collaborative networks of individuals. This ability to analyse KGs may be used in a harmful way. It is a sad fact that in some countries, personal relationships or research in certain subject areas can lead to discrimination, persecution or prison. We must, therefore, become aware of the risks and responsibilities that come with networked data in KGs. 

The trustworthiness of PID systems and KGs has so far been discussed in technical and organisational terms. The inclusion of personal data requires a new definition of ‘trust’ in the context of PID systems and Knowledge Graphs which should also include ethical aspects and consider the principles of the General Data Protection Regulation.

New, trustworthy technological approaches are required to ensure proper maintenance of privacy. As a prerequisite, the level of interoperability between PID needs to be enhanced. Further, new methods and protocols need to be defined which enable secure and prompt cascading update or delete actions of personal data between PID systems as well as knowledge graphs. 

Finally, new trustworthiness criteria must be defined which allow the identification of trusted clients for the exchange of personal data instead of the currently practised open data policy which can be in conflict with legislation protecting privacy and personal data.

[1] https://www.nybooks.com/daily/2014/05/10/we-kill-people-based-metadata/
Root strength comparison between early and late successional trees in a subtropical forest
Authors: Chen Cang-Wei , Song Guo-Zhang M. , Chang Li-Wan , Ko Chien-Jui , Lee Hsin-Tien , Hu Hung-Yen , Tseng Jie-hao
Published: March 2020

ABSTRACT    

Slope stability of forested areas is often determined by tree root strength. After landslides, the early successional species emerged first, followed by the late successional species. This study aimed to examine whether tree root strength varies as tree species change along with the succession sequence. The study site is in the Lienhuachi Experimental Forest in central Taiwan, where multiple landslides happened in 2008. Three dominant early (Mallotus paniculatus, Sapium discolor, and Schefflera octophylla) and three late successional species (Cryptocarya chinensis, Engelhardtia roxburghiana, and Randia cochinchinensis) were sampled to conduct the single-root-pull-out tests in the field. Root strength which varies with root diameters was estimated with the Root Bundle Model with the root-failure Weibull survival function (RBMw). Results showed that the overall root strength of the early successional tree species were higher than that of late successional species only when root diameter was lower than 5.44 mm. However, among the six species, the root strength of Sapium discolor, an early successional species, was highest and the species with the lowest root strength was a late successional species (Engelhardtia roxburghiana). To precisely estimate tree effects on slope stability, our results highlighted the need to collect root strength data specifically for each species, even though it will be a daunting task for areas rich in tree diversity.

Keyword: landslide, Root Bundle Model, vegetation succession
PM2.5 temporal source apportionment analysis over the Pearl River Delta region
Authors: Chen Yiang , Fung Jimmy Chi-Hung , Lu Xincheng
Published: March 2020

The Pearl River Delta (PRD) region is one of the most developed city clusters in China, and it is also the area that suffers from severe air pollution. A key problem in addressing pollution is to find out where the pollutants come and how to control them. Most of the previous studies focused on the source area, and source category contribution analysis, but fewer studies paid attention to the temporal contribution, which is also an important factor in policymaking. Therefore, in this study, based on the CAMx-PSAT model, we extended the model to track the contribution of the sources emitted at different periods. The updated PSAT can reflect the temporal correlation between the source and receptor and provide scientific support to efficient control policymaking. The simulation result of a high PM2.5 episode shows that the emission outside the PRD region is the major contributor to PM2.5 over the PRD region. PM2.5 mainly comes from the emission within the current two days. Under the control of the high-pressure system, low wind speed hinders the diffusion of PM2.5 and paves the way for the accumulation of the pollutants. The emission two days ago can still have a considerable contribution during the high concentration period. The results suggest that emission control measurements should be implemented in advance when adverse meteorology condition is predicted.
Source-to-Sink (S2S) analysis of a lacustrine system across the K-T boundary: the Yacoraite Formation, Salta rift basin, Argentina
Authors: Rohais Sébastien , Hamon Youri , Deschamps Rémy , Beaumont Valérie , Gasparrini Marta , Pillot Daniel , Romero-Sarmiento Maria Fernanda
Published: March 2020

In this contribution, we present a source-to-sink (S2S) analysis of the Late Cretaceous to Early Cenozoic Yacoraite Formation, a typical lacustrine source rock from the Salta rift Basin (NW Argentina). The Yacoraite Formation corresponds to a mixed carbonate-siliciclastic lacustrine sedimentary system, deposited during the sag phase (post-rift) and also records the K-T boundary. An integrated S2S approach was applied using sedimentary, geochronology, geochemical and isotopic datasets at basin scale (ca. 200 x 200 km), to better understand the complex interactions between production, destruction, and dilution processes that characterize the dynamic of organic-rich sediments. These data are used here to discuss the high-resolution (time step ca. 0.05-1 Myr) patterns of organic carbon enrichment in a lacustrine system across the K-T boundary.

Results show that the Yacoraite Formation recorded major climate changes that can be documented in terms of catchment dynamic, erosion processes, carbonate accumulation trends, lacustrine dynamic and source rock quality. The background organic matter corresponds to a Type I kerogen dominated by algal growth (mean HI 600-800 mgHC/gTOC, TOC0 1-2 wt.%). The K-T boundary was the climax of a climate change initiated ca. 0.3 Myr before that induced a major change in the catchment weathering processes, which temporally corresponds to the accumulation of poor quality source rock intervals (TOC0 ≤ 0.2 wt.% and HI < 50 mgHC/gTOC) in these series. The location of the K-T boundary is highlighted by a main negative anomaly in δ13C of the carbonate deposits in the Yacoraite Formation, as also supported by absolute U-Pb dating of inter-fingered volcanic ashes. It was followed by a major pulse in paleo-productivity, in turn followed by a major pulse in TOC0 (10-15 wt.%) under anoxic conditions. In ca. 0.2 Myr the lacustrine dynamic and the related organic-carbon enrichment resumed to their initial setting, just prior to the preluding K-T boundary climate change. The obtained results suggest that the Yacoraite Formation can be considered as a world-class example to illustrate how the K-T boundary is recorded in lacustrine sediments. In particular, it could be used as reference to address key questions related to cross-scale interactions, feedback loops and temporal dynamics in the sedimentary record.
Using a model-of-models approach and remote sensing technologies to improve flood disaster alerting
Authors: Schumann Guy J.-P. , Glasscoe Margaret , Bausch Douglas , Pierce Marlon , Wang Jun , Chen ZhiQiang , Eguchi Ronald , Huyck Charles , Tiampo Kristy , Kar Bandana
Published: March 2020

Floods are happening regularly in almost all places of the world and impact people, societies and economies, causing widespread devastation that can be hard to recover from. Yet, accurately predicting and alerting for floods is challenging, primarily since flood events are very local in nature and processes causing a flood can be very complex. In an era of open-access geospatial data proliferation as well as data and model interoperability, it makes sense to leverage on existing data and models, many of which are underutilized by decision-making applications. Thus, the objective of the project is to develop an open-access rapid alerting and severity assessment component for global flooding based on existing models and observation data sources. We do this within the DisasterAWARE platform of the Pacific Disaster Center (PDC).

This paper will outline the proposed concept of model-of-models that will leverage existing flood-hazard modeling capabilities, illustrating products that we will leverage, such as: GLOFAS (Global Flood Forecasting Feeds) probabilistic hydrologic data, IMERG (The Integrated Multi-satellitE Retrievals for GPM) observed precipitation grids, GDACS (Global Disaster Alerting Coordination System) anomaly points, GFMS (Global Flood Monitoring System) depth above baseline grids, the NASA MODIS (Moderate Resolution Imaging Spectroradiometer) and Dartmouth Observatory flood maps, as well as new models as they are developed. We will further combine the flood hazard data with existing exposure data to estimate property loss using a probabilistic fragility approach. With the use of an end-to-end deep learning framework, structural damage will be detected using different remote sensing data. The approach will further incorporate other, non-routinely-generated remotely-sensed products for ground-truthing for areas and events where and when such products are available.

The existing resilience and capacity of communities to rapidly respond to and recover from flood impacts will be incorporated into the severity determination on an administrative area and watershed risk basis. This model-of-models approach will leverage major efforts, improve reliability and reduce false triggers by ensuring two or more models agree.
Invalid cloud top properties product of Fengyun-4A satellite imager induced by infrared calibration bias
Authors: Min Min , Wang Fu , Xu Na
Published: March 2020

Recently, China successfully launched the new-generation geostationary (GEO) meteorological satellites, Fengyun-4A (FY-4A) in the year of 2016. In general, many mature and useful level-2 science product of Advanced Geostationary Radiation Imager (AGRI) onboard FY-4A were well developed in advance for satellite data users. Cloud top properties (CTP, including cloud top height, temperature, and pressure) product as an important science product is always used to monitor the rapid changes of typhoon and weather systems in the operational application. Unfortunately, we still find some invalid retrievals in CTP product of FY-4A/AGRI, which seriously impact on the use of this product (get some complaints from users). After comparing the invalid pixels with valid pixels and the same CTP product of Japanese Himawari-8 satellite and radiative transfer simulations, we find that the radiometric calibration bias of infrared band at 13.5μm is the primary impact factor on this fault. The pixels with brightness temperature lower than 200K show a bias larger than 7-8K, which directly induce the invalid retrieval process in the CTP product of FY-4A/AGRI. However, this fault in CTP also inspire us to use the invalid CTP pixel to monitor the on-orbit radiometric calibration bias of infrared band in the future.
Numerical modelling of the benthic-pelagic coupling in coastal marine ecosystems at contrasting sites
Authors: Amadio Carolina , Zavatarelli Marco , Lovato Tomas , Butenschoen Momme
Published: March 2020

Continental shelves cover less than 5% of the global ocean surface, but play a crucial role in the marine global biogeochemical cycling. Coastal ecosystem dynamics are governed and constrained to a wide extent by the biogeochemical processes occurring in the benthic domain. Such processes define the so called benthic-pelagic coupling (hereafter BPC), i.e. two-way exchange of organic matter (particulate and dissolved) and inorganic compounds. The physically mediated exchanges structuring the BPC are constituted by the sinking and resuspension fluxes of particulate organic matter and by the diffusion of inorganic nutrients. Despite its importance and the continuous enhancement of model resolution, the BPC in global marine ecosystem models is generally roughly approximated. Moreover, observational data focusing on the BPC dynamics are fairly scanty in time and space, thereby hampering model parameterization and validation. The main objectives of this study are to develop and test a numerical model addressing BPC processes and to evaluate ecosystem dynamics in marine areas with different climatic and ecological characteristics. In particular, we here focused on two key interaction processes: the sinking velocity of particulate matter and the diffusive fluxes of inorganic dissolved nutrients at the benthic-pelagic interface. The benthic sub-model has been calibrated accounting for the complex pelagic food web and for the main ecological and physical characteristics of continental shelf areas in different sites: Gulf of Trieste (Italy), St. Helena Bay (South Africa), Svinoy Fyr (Norway). At each study area, the one-dimensional coupled BFM-NEMO modelling system was setup by prescribing temperature and salinity vertical profiles in NEMO, while the shortwave radiation acts as a primary forcing of BFM. Model results have been validated with available in situ data.

Sensitivity tests has been performed to investigate the role of the BPC exchanges in determining the pelagic biogeochemical cycles and to carry out a comparative analysis accounting for each site characteristics.
​​Distributed Earth-Observation satellite data processing with Pytroll/Satpy
Authors: Eliasson Salomon , Raspaud Martin , Dybbroe Adam
Published: March 2020

 

As earth-observing (EO) satellite data volume is growing, servers struggle to keep up with the computational load needed to process even single segments of satellite data with reasonable performance. Pytroll is a suite of free and open-source python tools from which the Satpy package is made to easily and efficiently read, process, write EO satellite data. To obtain computational efficiency, Pytroll approaches the performance problem from multiple angles through optimized data processing, built-in support for out-of-memory computations (using the underlying Dask python library), and allowing distributed processing (using the Dask Distributed tools). In this work, we will show how large volumes of satellite data can be read, processed, resampled, and written swiftly and easily with the Pytroll/Satpy package, in a cluster environment. Specifically, examples of efficiently processing Sentinel-1, Sentinel-2, and Himawari/AHI data will be shown, along with performance figures.
Monitoring fire-affected areas using temporal profiles of spectral signal from time series MODIS satellite images
Authors: Tsipoka Konstantina , Koutsias Nikos
Published: March 2020

Vegetation phenology is an important element of vegetation characteristics that can be useful in vegetation monitoring especially when satellite remote sensing observations are used. In that sense temporal profiles extracted from spectral signal of time series MODIS satellite images can be used to characterize vegetation phenology and thus to be helpful for monitoring vegetation recovery in fire-affected areas. The aim of this study is to explore the phenology patterns and the vegetation recovery pattern of various wildfires occurred in Greece during the period 2000-2020. Satellite remote sensing data from MODIS satellites in the period from 2000 to 2020 were acquired and processed to extract the temporal profiles of the spectral signal for selected areas inside and outside the fire-affected areas. This dataset and time period analyzed together with the time that these fires occurred gave the opportunity to create temporal profiles for some years before and some years after the fire. Different metrics linked to key phenological events have been created and used to assess vegetation recovery in the fire-affected areas. Apart of the use of the original spectral data we estimated and used vegetation indices commonly found in vegetation studies as well as in burned area mapping studies. In this study we explore the strength and the use of these time series satellite data to characterize vegetation phenology as an aid to assess the fire-affected areas and to monitor their vegetation recovery.
Mineralogical and structural characterization of massive sulphide deposits in the Iberian Pyrite Belt using hyperspectral digital outcrops
Authors: Kirsch Moritz , Lorenz Sandra , Thiele Samuel , Zimmermann Robert , Khodadadzadeh Mahdi , Tusa Laura , Gloaguen Richard
Published: March 2020

In this contribution, we present integrated hyperspectral and photogrammetric models from three abandoned open pit mines in the Iberian Pyrite Belt: Corta Atalaya, Tharsis, and Peña de Hierro. On those three examples, we showcase the usefulness of these data for the characterization of volcanogenic massive sulphide (VMS) mineral deposits. The digital outcrop models are generated by co-registering Structure-from-Motion photogrammetric point clouds of the mine faces with radiometrically corrected hyperspectral images in the visible–near and short-wave infrared range. We then use advanced unmixing and supervised classification techniques to distinguish and map the massive sulphide and stockwork mineralization, their sedimentary, volcanic and volcaniclastic host rocks, and domains of hydrothermal and supergene alteration. The enhanced outcrop models also enable a semi-automatic delineation of discontinuities on the point clouds guided by changes in the hyperspectral attributes, and an estimation of structure orientations from their intersection with the surface to derive simple 3D geological models.
Thermo-poromechanical induced seismic effects during diking
Authors: Nagel Thomas , Parisio Francesco , Rivalta Eleonora , Vinciguerra Sergio
Published: March 2020

Dike propagation in the earth crust, often a precursor of major volcanic eruptions, usually generates a seismic response by activating small fractures (micro-seismicity) and larger existing faults (greater magnitude events). The conceptual interpretation is essentially viewed as a fluid-driven fracture advancing in the rock mass and altering the existing state of stress in its surroundings. Because dikes are filled with high-temperature magma, which can exceed 1000 °C, it is likely that they will alter the initial temperature while propagating. The temperature increase can generate pore water pressurization as a function of its rate of change. Pore pressure in turns diffuses through the porous and fractured rock, altering the initial effective stress state. Additionally, hot dikes also generate thermally-induced stresses. The stress changes in the rock are therefore affected by temperature and pore pressure as much as they are by mechanically induced fracturing. In this contribution, we have studied the coupled processes of temperature, pore pressure and deformation induced by diking. We have employed finite element analyses to solve the boundary value problem of a progressing dike. The main goal is to highlight the effects generated by temperature increase in the rock surrounding the dike. Thermal pressurization depends on heat loading rate, hence on diking advancement speed, and on surrounding rock permeability. Rock permeability also controls the diffusion of pore pressure, the size of the area affected by pressurization and the magnitude of pressurization. Results from numerical models show that positive Coulomb stress changes (instabilities) can be triggered by thermal effects at several hundred meters away from the dike, implying that even non-advancing dikes could generate a seismic response. We prove the importance of accounting for thermo-poromechanical effects in studying the seismic response during diking, a widely unexplored field which could have major implications for the assessment of volcanic eruptions’ precursory signals.
Learning recurrent transfer functions from data: From climate variability to high river discharge
Authors: Norel Mateusz , Krawiec Krzysztof , Kundzewicz Zbigniew
Published: March 2020

Interpretation of flood hazard and its variability remains a major challenge for climatologists, hydrologists and water management experts. This study investigates the existence of links between variability in high river discharge, worldwide, and inter-annual and inter-decadal climate oscillation indices: El Niño-Southern Oscillation, North Atlantic Oscillation, Pacific Interdecadal Oscillation, and Atlantic Multidecadal Oscillation. Global river discharge data used here stem from the ERA-20CM-R reconstruction at 0.5 degrees resolution and form a multidimensional time series, with each observation being a spatial matrix of estimated discharge volume. Elements of matrices aligned spatially form time series which were used to induce dedicated predictive models using machine learning tools, including multivariate regression (e.g. ARMA) and recurrent neural networks (RNNs), in particular the Long Short Term Memory model (LSTM) that proved to be effective in many other application areas. The models are thoroughly tested and juxtaposed in hindcasting mode on a separate test set and scrutinized with respect to their statistical characteristics. We hope to be able to contribute to improvement of interpretation of variability of flood hazard and reduction of uncertainty.