bluuebunny/crossref_metadata_2025 huggingface dataset:
GOAL: an international project to develop geoethics and its educational potential
Authors: Di Capua Giuseppe , Peppoloni Silvia
Published: March 2020

“GOAL - Geoethics Outcomes and Awareness Learning” (https://goal-erasmus.eu/) is an international partnership project aimed to develop the potential of geoethics with the aim of improving its concepts and practices through an innovative and creative approach. The members of the different partner countries (Portugal, Austria, Italy, Israel, Spain, Lithuania) are working bringing together their expertise in overlapping disciplinary areas and intellectual synergies to develop an articulated approach and contribute to an advancement of the geoethical thinking. In particular the project integrates researchers and practitioners with skills in geoscience education, geological heritage, georisks, environmental sciences, theoretical aspects of geoethics and information and communication technologies in education.

The project "GOAL" aims to develop a geoethics syllabus and to offer suggestions on educational resources to be used in Higher Education, in order to promote awareness-raising on ethical and social implications of geoscience knowledge, education, research, practice and communication, thus enhancing the quality and relevance of students’ knowledge, skills and competencies. The creation of this international network and subsequently the syllabus and other educational resources will develop operational capacities for strengthening the conceptual substratum of geoethics.

The Italian team has contributed to frame geoethics from a theoretical point of view, by introducing definitions, values and contents. It has also clarified some concepts of utmost importance in geoethics, like that of responsibility, intellectual freedom, research integrity, , prevention, sustainability, resilience, etc. Moreover, some specific issues have been addressed, such as the difference between ethical issues and ethical dilemmas, as well as the necessity to reach a reasonable alignment of values when dealing with geological activities that may have an impact on environment and population. Finally, through the use of videos, some important connections that link geoethics to several geosciences issues have been explained, such as georisks and georesources management.

The target group of GOAL project is formed mainly by Higher Education students, professors and researchers. Practitioners in the field like, for example, “geoheritage site” guides and secondary teachers, are also groups of interest for the project activities.
Assimilation of aircraft observations in the South China Sea to improve forecasts of tropical cyclones
Authors: Gao Yudong
Published: March 2020

High frequency (20 Hz) aircraft observations from the Government Flying Service of the Hong Kong Government, penetrating a tropical cyclone (TC) at low altitude over the South China Sea had an extremely inhomogeneous distribution. Today the remoting observations have been widely used, but our work demonstrates aircraft observations still play an important role in TCs forecasts.

To investigate an effective scheme for assimilating inhomogeneous aircraft observations, a multigrid 3D variation (m3DVAR) system, with the assistance of a bogus vortex, was employed. Track and intensity forecasts were improved by assimilating aircraft observations and bogus data. The assimilation of pressure (horizontal wind) was also found mainly to contribute to the large magnitude (sophisticated distribution) of increments.

These aircraft observations were also thinned by arithmetic means over different time intervals to identify structures of tropical cyclone at different scales. It is found that the thinning process can reduce serial correlation in observational errors and enhance the representation of aircraft observations. The changes in dynamic structures indicate that the imbalance generated from assimilating aircraft observations at the sub-grid scale can be alleviated by using longer time intervals of the arithmetic mean. Assimilating aircraft observations at the grid scale achieves optimal forecasts based on verifications against independent observations and investigations of environmental and ventilation flows.

In fact, the west Pacific had access to aircraft observations but these observations stopped in 1987. We hope we can call attentions of governors and scientists to reboot in situ observations on aircraft platform in the west Pacific by disseminating our results. This can be a significant benefit to improving the regional real-time forecasts and understanding the climate variabilities of TCs. We already had two publications related to the assimilation of aircraft observations (Gao et al., 2019; Gao et al., 2019).

 

References:

Gao, Y, Xiao, H, Chan, PW, Hon, Kai kwong, Wan, Q, Ding, W. Application of the multigrid 3D variation method to a combination of aircraft observations and bogus data for Typhoon Nida (2016). Meteorol Appl. 2019; 26: 312– 323. https://doi.org/10.1002/met.1764.

 

Gao, Y.; Xiao, H.; Jiang, D.; Wan, Q.; Chan, P.W.; Hon, K.K.; Deng, G. Impacts of Thinning Aircraft Observations on Data Assimilation and Its Prediction during Typhoon Nida (2016). Atmosphere 2019, 10, 754. https://doi.org/10.3390/atmos10120754.
Towards a quantitative paleogeography calculator
Authors: van der Linden Thomas , Dupont-Nivet Guillaume , van Hinsbergen Douwe
Published: March 2020

Studies of paleoclimatology, paleoceanography, paleobiology, and other studies of paleoenvironment require paleogeographic reconstructions that display the past distribution of land and sea, and of bathymetry and altimetry. Quantitative reconstructions of past positions of continents and oceans have been available for decades, and have become easy to access and develop with the advance of GPlates software. Quantitative estimates of bathymetry and especially altimetry and topography, however, are considerably more challenging to develop. First attempts towards a global, quantitative approach towards paleotopography reconstruction were made in recent years. However these models are largely based on present day topography and require extensive manual adjustment for local modification that is subjective and precludes reproducibility. In this project, we attempt to overcome this subjectivity, and develop a quantitative methodology to calculate paleogeography based on kinematic input parameters.

Our aim is to develop ‘Paleogeography.org’, a free, online paleogeography calculator. This project calculates oceanic bathymetry and continental altitude and topography from plate tectonic reconstructions for various geodynamic settings. The algorithms are based on simple and straightforward dynamic principles: bathymetry of the ocean floor is at first order inferred from its age, and altimetry is based on computing crustal thickness based on shortening or extension reconstructions, assuming isostacy. Distinctions are made between undisturbed ocean floor, oceanic plateaus, trenches, continental rifts and back-arc basins, oceanic and continental volcanic arcs, upper plate orogens (e.g., Andes, Tibet) vs accretionary orogens (Zagros, Himalaya, Apennines, Alps), etc. This allows to calculate a global geography for any given time slice for which underlying kinematic reconstructions are available. These reconstructions are subsequently tested against independent quantitative estimates of e.g., altimetry and bathymetry and iterated where necessary. This approach provides a reproducible, global estimate of paleogeography without input from paleobiological or paleoclimatic indicators, enabling an independent platform for paleo-environmental study. The iteration between prediction and observation, moreover, will provide novel constraints on 4D geodynamic processes.

Code is written mainly in Python, especially using pyGPlates. The calculator will be available as open source code for scientists and other professionals. They can use it to make reproducible paleogeographic reconstructions based on their own plate tectonic reconstructions or on specific moments in time. In addition the output makes appealing pictures of plate tectonic reconstructions for both scientists and a wider audience.
Identifying the sensitive area in targeted observation for improving the vertical thermal structure prediction in the summer Yellow Sea
Authors: Liu Kun , Liu Jingyi , Hu Huiqin , Guo Wuhong , Cui Baolong
Published: March 2020

The sensitive area of targeted observation for the short-term prediction of the vertical thermal structure in the summer Yellow Sea is investigated by utilizing the Conditional Nonlinear Optimal Perturbation (CNOP) method and a adjoint-free algorithm with the Regional Ocean Modeling System. We use a vertical integration scheme of temperature to locate the sensitive area, in which reducing the initial errors are expected to yield great improvements in vertical thermal structure prediction of the verification area. We perform a series of sensitivity experiments to evaluate the effectiveness of the identified sensitive area. Our results show that, initially adding random perturbations in the sensitive area have the greatest negative effects on the prediction than in other areas (eg. the verification area, regions east and northeast of the verification area). Moreover, Observing System Simulation Experiments (OSSEs) indicate that, eliminating the initial errors in the sensitive area can lead to a more refined prediction than in other selected areas (including the verification area itself). Our study suggests that implementing targeted observation is a feasible way to improve the short-term prediction of the vertical thermal structure in the summer Yellow Sea.
Nd, Sr and stable isotope signatures of ancient methane-seep carbonates (Eocene, Washington, USA) as a record of incipient subduction at the Cascadia convergent margin
Authors: Jakubowicz Michał , Kiel Steffen , Goedert James , Dopieralska Jolanta , Belka Zdzislaw
Published: March 2020

Stratigraphic and structural context of the early evolution of the Cascadia convergent margin, following major subduction reconfiguration associated with accretion of the igneous Siletzia terrane at 50−45 Ma, remains insufficiently understood. Here, we have applied a novel approach that uses combined Nd, Sr and stable isotope analyses of ancient methane-seep carbonates to constrain the early hydrogeological regime of the Cascadia margin. Analyses included the oldest-known seep deposits of Cascadia, formed during mid-Eocene time (42.5−40.5 Ma). A combination of exceptionally high εNd and low 87Sr/86Sr signatures observed in these carbonates consistently point to former interactions between the seeping fluids and mafic, igneous constituents of the forearc basement. Moderately negative δ13Ccarbonate values imply thermogenic origin of hydrocarbons at three out of four studied seeps, with likely contribution of biogenic methane at a single, landward-most site. When combined with structural constraints, the recorded signals point to discharges of fluids originating from deep portions of the young subduction wedge, and their channeled ascent through the Siletzia terrane. The results document the presence of a fluid expulsion system indicative of active convergence prior to maturation of typical arc magmatism in the Cascades at 40 Ma. The exceptionally pronounced role of exotic, 143Nd-enriched, 87Sr- and 18O-depleted fluids recorded for early Cascadia reflects its distinctive structural architecture, including the relatively thin sedimentary cover of the young forearc, its extensional tectonics, and the near-trench position of the volcanic terrane that the descending plate-derived fluids must have migrated through prior to reaching the seafloor.
A Decomposition of Feedback Contributions to the Arctic Temperature Biases in the CMIP5 Climate Models
Authors: Park Tae-Won , Park Doo-Sun
Published: March 2020

The systematic temperature biases over the Arctic Sea in the CMIP5 models are decomposed into partial biases due to physical and dynamical processes, based upon the climate feedback-responses analysis method (CFRAM). In the frame of the CFRAM, physical processes are also divided into water vapor, cloud, and albedo feedbacks. Though the Arctic temperature biases largely depend on models, considerable cold bias are found in most of models and ensemble mean. Overall, temperature biases corresponding to physical and dynamical processes tend to cancel each other out and total biases equal to their sums are geographically similar to those related to physical processes. For the physics-related biases, a contribution of albedo feedback is the largest, followed by cloud and water vapor feedbacks in turn. Quantitative contributions of the processes to temperature biases are evaluated from area-mean values over the entire Arctic Sea, Barents-Kara Sea, and Beaufort Sea. While relationships between total and partial biases over the Arctic Sea show the large model-dependency, in the local-scale, total temperature biases over Barents-Kara Sea and Beaufort Sea are made from consistent contributions among models. An overestimate (underestimate) of specific humidity and cloud fraction in models are responsible for an overall warm (cold) biases through longwave heating rates of the greenhouse effect. Shortwave cloud forcing by cloud fraction biases offsets a substantial part of biases related to longwave cloud forcing, while shortwave effect of specific humidity bias plays a minor role on water vapor feedback. The fact that geographical distribution of sea-ice biases is mostly opposite to that of partial temperature bias due to albedo feedback indicates that the biased simulation of sea-ice in models are the main contributors in albedo feedback.
Identification and preliminary analysis of dust impacts on the MAVEN spacecraft
Authors: Ševčíková Klára , Němec František , Nouzák Libor , Vaverka Jakub , Andersson Laila
Published: March 2020

Electric field data obtained by the Langmuir Probe and Waves (LPW) instrument on board the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft are used to identify signals related to dust impacts on the spacecraft body and/or on the instrument probes. The analyzed waveforms snapshots are 62.5 ms long (4,096 points sampled at 65,536 Hz). An automatic procedure to identify short electric field pulses with signatures corresponding to those expected for the dust impacts has been developed and applied to available data in years 2014–2018, resulting in about 40,000 of events. Each of the identified pulses is characterized by several quantitative parameters (polarity, magnitude, relaxation time, magnitude of a possible pre-spike). The event occurrence and respective quantitative parameters of detected pulses are then analyzed as a function of local plasma conditions in the Martian ionosphere (electron density and temperature), the spacecraft location, and the spacecraft potential. The obtained results are compared with a simple scheme of the signal formation upon a dust impact.
Variations of Pressure Profiles from the Bow Shock to Magnetopause
Authors: Pi Gilbert , Němeček Zdeněk , Šafránková Jana
Published: March 2020

Numerous simulation results have shown that the spatial profiles of a thermal pressure from the bow shock to the magnetopause are determined by the upstream interplanetary magnetic field (IMF) orientation. The southward IMF conditions lead to an increasing trend of thermal pressure with a maximum near the magnetopause. In contrast, the thermal pressure increases on the plasma entry to the  magnetosheath, but this trend turns to a decreasing one after passing a middle point between the bow shock and magnetopause during northward IMF intervals. In the present study, we show the observation results, both particular events and statistics, to check the variations of pressure profiles in the magnetosheath and their relation to upstream IMF conditions. THEMIS-C observartions during 2007–2009 are used. The profiles near the Sun–Earth line and the global pressure distribution in the dayside equatorial magnetosheath are shown.
Pathways of ocean heat towards Pine Island and Thwaites grounding lines
Authors: Nakayama Yoshihiro , Manucharyan Georgy , Zhang Hong , Dutrieux Pierre , S. Torres Hector , Klein Patrice , Seroussi Helene , Schodlok Michael , Rignot Eric , Menemenlis Dimitris
Published: March 2020

In the Amundsen Sea, modified Circumpolar Deep Water (mCDW) intrudes into ice shelf cavities, causing high ice shelf melting near the ice sheet grounding lines, accelerating ice flow, and controlling the pace of future Antarctic contributions to global sea level. The pathways of mCDW towards grounding lines are crucial as they directly control the heat reaching the ice. A realistic representation of mCDW circulation, however, remains challenging due to the sparsity of in-situ observations and the difficulty of ocean models to reproduce the available observations. In this study, we use an unprecedentedly high-resolution (200 m horizontal and 10 m vertical grid spacing) ocean model that resolves shelf-sea and sub-ice-shelf environments inqualitative agreement with existing observations during austral summer conditions. We demonstrate that the waters reaching the Pine Island and Thwaites grounding lines follow specific, topographically-constrained routes, all passing through a relatively small area located around 104ºW and 74.3ºS. The temporal and spatial variabilities of ice shelf melt rates are dominantly controlled by the sub-ice shelf ocean current. Our findings highlight the importance of accurate and high-resolution ocean bathymetry and subglacial topography for determining mCDW pathways and ice shelf melt rates. 

We also briefly introduce our various existing model outputs focusing on the Amundsen Sea and demonstrate how to access these model outputs, plot some basic variables, and create animations. We hope that these model output can be utilized for many different aspects of oceanographic researches including observational planning, data analysis for physical, biological and chemical oceanography, and boundary conditions for ocean and ice sheet models. 

 
Quantifying non-CO2 contributions to remaining carbon budgets
Authors: Jenkins Stuart , Cain Michelle , Friedlingstein Pierre , Gillett Nathan , Allen Myles
Published: March 2020

The IPCC Special Report on 1.5°C concluded that the maximum level of anthropogenic global warming is “determined by cumulative net global anthropogenic CO2 emissions up to the time of net zero CO2 emissions and the level of non-CO2 radiative forcing” in the decades prior to the time of peak warming. Here we quantify this statement, using CO2-forcing-equivalent (CO2-fe) emissions to calculate remaining carbon budgets without treating available mitigation scenarios as a representative sample of possible futures.

CO2-fe emissions are used to calculate an observationally-constrained estimate of the Transient Climate Response to cumulative Emissions (TCRE) using a large ensemble of historical radaitve forcing timeseries. This observationally-constrained TCRE is used to calculate remaining total CO2-fe budgets from 2018 to 1.5°C, which we compare with results discussed in Chapter 2, SR15. We consider contributions to this total remaining budget from CO2 and non-CO2 sources using both historical observations and the available mitigation scenarios in the IAMC scenario database.

We calculate remaining CO2 budgets for a 33, 50 or 66% chance of limiting peak warming to 1.5°C and use these to assess the extent to which scenarios in the IAMC scenario database are consistent with ambitious mitigation as outlined in the Paris Agreement. We argue that, assuming no change in the definition of observed global warming and no increase in TCRE due to non-linear feedbacks, scenarios currently classified as “lower 2°C-compatible” are consistent with a best-estimate peak warming of 1.5°C.
The influence of aggregation and statistical post-processing on the sub-seasonal predictability of European temperatures
Authors: van Straaten Chiem , Whan Kirien , Coumou Dim , van den Hurk Bart , Schmeits Maurice
Published: March 2020

The succession of European surface weather patterns has limited predictability because disturbances quickly transfer to the large scale flow. Some aggregated statistic however, like the average temperature exceeding a threshold, can have extended predictability when adequate spatial scales, temporal scales and thresholds are chosen. This study benchmarks how the forecast skill horizon of probabilistic 2-meter temperature forecasts from the ECMWF sub-seasonal forecast system evolves with varying scales and thresholds. We apply temporal aggregation by rolling window averaging and spatial aggregation by hierarchical clustering. We verify 20 years of re-forecasts against the E-OBS data set and find that European predictability extends at maximum up to week 4. Simple aggregation and standard statistical post-processing extend the forecast skill horizon with two and three skillful days on average, respectively.
The intuitive notion that higher levels of aggregation capture the larger scale and lower frequency variability and therefore tap into an extended predictability, holds in many cases. However, we show that the effect can saturate and that regional optimums exist, beyond which extra aggregation reduces the forecast skill horizon. We expect that such windows of predictability result from specific physical mechanisms that only modulate and extend predictability locally. To optimize sub-seasonal forecasts for Europe, aggregation should in certain cases thus be limited.
Ethical recommendations for Sustainable development of algae aquaculture.
Authors: Barbier Michele , Charrier Bénédicte
Published: March 2020

Macroalgae, also called seaweed, play a key ecological role in coastal ecosystems and can be used for a variety of applications, including food, health products, cosmetics, agriculture and environmental management. Well-developed in Asia, the seaweed aquaculture is also a growing economic sector in Europe that can contribute to a sustainable circular bioeconomy. However, this sector lacks specific legislation to regulate its development. To ensure the environmental and economic sustainability of this sector, a group of experts has designed the European guidelines for sustainable development of seaweed aquaculture, PEGASUS, in a participatory and co-designed manner. The scientific, technical, environmental, legal and socio-economic dimensions have been taken into account to anticipate any potential risks associated with aquaculture development. Combining the expertise of SMEs and researchers, these guidelines have been published and presented to the European Parliament to help all stakeholders in the sector to understand the different aspects of seaweed aquaculture. All actors in the sector, such as farmers, suppliers, users, researchers and decision-makers, should establish a collaborative network along the value chain to guide strategic development plans and ensure environmental sustainability.

Ethical recommendations extracted and inspired from this work for better governance and preservation of the marine environment will be presented
GeoNEX: Earth observations from operational geostationary satellite systems
Authors: Nemani Rama , Lee Tsengdar , Kalluri Satya , Ichii Kazuhito , Yeom Jong-Min
Published: March 2020

The NASA Earth Exchange (NEX) team at Ames Research Center has embarked on a collaborative effort involving scientists from NASA, NOAA, JAXA/JMA, KMA/KARI exploring the feasibility of producing EOS-quality research products from operational geostationary satellite systems for climate monitoring. The latest generation of geostationary satellites (Himawari 8/9, GOES-16/17, Fengyun-4, GeoKompsat-2A) carry sensors that closely mimic the spatial and spectral characteristics of widely used polar-orbiting, global monitoring sensors such as MODIS and VIIRS. More importantly, they provide observations as frequently as 5-15 minutes. Data from various currently operating geostationary platforms provide a geo-ring of hyper-temporal, multispectral observations. Such high frequency observations, particularly when combined with data from polar orbiters, offer exciting possibilities for improving the retrieval of geophysical variables by overcoming cloud cover, enable studies of diurnally varying phenomena over land, in the atmosphere and the oceans, and help in operational decision-making in agriculture, hydrology and disaster management. Beyond the weather-focused geo-sensors, a number of new spectrometers are scheduled to be launched in the next five years in geostationary orbit to study atmospheric pollution (GEMS, TEMPO), ocean color (GOCI) and carbon cycling (GeoCARB). This talk will highlight new research, data sets, algorithms and computational platforms that utilize data from geostationary satellites to advance our ability to monitor the environment and create climate resiliency.
Resolving the differences in the simulated and reconstructed climate response to volcanism over the last millennium
Authors: Zhu Feng , Emile-Geay Julien , Hakim Greg , King Jonathan , Anchukaitis Kevin
Published: March 2020

Explosive volcanism imposes impulse-like radiative forcing on the climate system, providing a natural experiment to study the climate response to perturbation. Previous studies have identified disagreements between paleoclimate reconstructions and climate model simulations (GCMs) with respect to the magnitude and recovery from volcanic cooling, questioning the fidelity of GCMs, reconstructions, or both. Using the paleoenvironmental data assimilation framework of the Last Millennium Reanalysis, this study investigates the causes of the disagreements, using both real and simulated data. We demonstrate that the disagreement may be resolved by assimilating tree-ring density records only, by targeting growing-season temperature instead of annual temperature, and by performing the comparison at proxy locales. Our work suggests that discrepancies between paleoclimate models and data can be largely resolved by accounting for these features of tree-ring proxy networks.
Application of frequency ratio model for GIS potential mapping of groundwater suitable for drinking
Authors: Koh Eun-Hee , Kim Hyun Jung , Lee Kang-Kun
Published: March 2020

Groundwater resource has been utilized for various fields and especially, food and beverage industry using groundwater has grown its scales. According to the groundwater use purposes, groundwater quality should be suitable for each type of object securing higher productivity. However, groundwater quality shows very diverse characteristics due to being affected by various processes (water-rock interaction, biochemical reactions, and contamination), it is challenging to determine an occurrence location of groundwater which is suitable for its purpose of use. The objective of this study is to map groundwater suitability for drinking water and brewing coffee by using the frequency ratio (FR) model. The study area is Gangwon Province in South Korea being famous for good quality of groundwater. A total of 2,215 groundwater quality data were collected in the study area, and 893 data were selected to determine a suitability index for drinking water and brewing coffee. For conducting the FR model, environmental GIS data (elevation, land use, hydrogeology, soil depth, soil property, and soil drainage) known to have a close correlation with groundwater quality were utilized. Based on relations between the GIS data and the suitability index of groundwater, potential maps of groundwater for drinking water and brewing coffee were delineated for the entire study area. Higher FR values were calculated for coniferous forest, sedimentary and carbonate rocks, moderately drained and loamy soil, which indicates positive impacts on suitable groundwater occurrence for drinking water and brewing coffee. After combining all FR layers for individual GIS data, we could generate groundwater potential maps for each water use purpose. The results of this study enable us to have a decision making based on the scientific data analysis for seeking a proper location of groundwater resources suitable for purposes of water use.   

 

Acknowledgements: This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2018R1D1A1B07040283) and by the National Research Council of Science & Technology (NST) grant by the Korea government (MSIP) (No. CAP-17-05-KIGAM).
A Study on the Difference of Urban and Rural Resilience under Climate Change- A Case Study of Chiayi County
Authors: Pai Shin-En , Chang Hsueh-Sheng
Published: March 2020

In recent years, the impact of climate change has caused critical risks to urban and rural systems, how to mitigate the damage caused by extreme climate events has become a topic of considerable concern in various countries in recent years. The United Nations International Strategy for Disaster Reduction (UNISDR) mentioned in the Hyogo Framework for Action (HFA) and the Sendai Framework for Disaster Risk Reduction 2015-2030 (Sendai Framework) that improving community resilience will help to deal with the harm caused by climate change. However, most of the previous research on resilience have only focused solely on urban or rural only, and have failed to clearly identify the differences in resilience between urban and rural areas. In fact, if we can understand the difference in resilience between urban and rural in the face of climate change, it will provide planners with better planning strategies or resource allocation. Based on this, the study first developed the resilience index through literature review, and then filtered and screened the index through Principle Component Analysis (PCA). After that, the resilience index was applied to empirical areas, and the spatial correlation of resilience was explored through Local Indicators of Spatial Autocorrelation (LISA). Finally, the binary logistic regression is used to analyze the difference in resilience of urban or rural under climate change.
Effects of pore-throat structure on reservoir blockage and wettability alteration during CO2 injection
Authors: Wang Qian , Glover Paul , Lorinczi Piroska
Published: March 2020

Injection of CO2 into subsurface reservoirs occurs during Enhanced Oil Recovery (EOR) and also during Carbon Capture and Storage (CCS) operations. During CO2 injection, the efficacy and distribution of fluid flow in sandstone reservoirs is controlled by the pore-throat microstructure of the rock. Furthermore, CO2 injection promotes asphaltene precipitation on the pore surface and can also affect fluid flow in the pore throats, decreasing the permeability and altering reservoir wettability. In this work, miscible and immiscible CO2 flooding experiments under reservoir conditions (up to 70â„ƒ, 18 MPa) have been carried out on four samples with very similar permeabilities but different pore-throat structures in order to study the effects of pore-throat microstructure on formation damage. The features of pore-throat structure were evaluated by fractal theory, based on pore size distributions and rate-controlled porosimetry (RCP) mercury intrusion curves. Reservoir rocks with smaller pore throat sizes and more heterogeneous and poorer pore-throat microstructures were found to be more sensitive to asphaltene precipitation, with corresponding 15-20% lower oil recovery and 4-7% greater decreases in permeability than that of rocks with homogeneous and better pore-throat microstructure. However, the water-wettability index of cores with larger and more connected pore-throat microstructures was found to drop by an extra 15-25% than heterogeneous core due to more asphaltene precipitation caused by the larger sweep volume of injected CO2 they consequently experienced, which is a disadvantage for EOR. In addition, immiscible flooding exacerbates the differences from 4-7% to 8-15% in permeability decline of the rocks with different pore-throat structures. Miscible flooding leads to more asphaltenes being precipitated from the crude oil, triggering in average an extra 11% change in wettability in comparison to immiscible flooding.

 

Keywords: CO2 flooding, asphaltene precipitation, pore size distribution, pore-throat microstructure, reservoir blockage, wettability alteration
The distributions of Glomalin-related soil protein in the coastal wetlands of the Liaohe Delta, Northeast China: Implications for mineral weathering and carbon sequestration
Authors: Pei Lixin , Ye Siyuan , Yuan Hongming , Pei Shaofeng , Xie Shucheng , Wang Jin
Published: March 2020

The role of Arbuscular mycorrhizal fungi (AMF) in conditioning soils is achieved by its metabolite glomalin. However, glomalin has not been biochemically defined, it has often been quantified in terms of Glomalin-related soil protein (GRSP). Therefore, as a proxy for AMF, GRSP has been widely used to explore the role of AMFs in various ecosystems around the world. However, information on AMF-carbon-weathering interactions is limited. To evaluate the relationship among the AMF, carbon content, nutrients and chemical index of alteration (CIA), GRSP in 133 surface sediment samples and the major components, nutrient content and the grain size of 304 surface sediment samples were analyzed in the wetlands of the Liaohe Delta (LHD), including the upper delta plain wetlands (UDPW) and its adjacent shallow sea wetlands (SSW). The GRSP concentrations averaged over 133 samples were 2.30 ± 0.17 mg g-1, in a range between 0.11 and 11.31mg g-1, and significantly affected by the land use pattern. The ratios of organic carbon in GRSP (GRSP-C) to soil organic carbon (SOC) ranged between 0.71 and 25.34%, with an average of 10.34 ± 0.52%, confirmed that GRSP was an important part of the sediment carbon pool in the LHD. In addition, it is worth noting that the carbon dynamics in these wetlands were closely related to human activities. The CIA values varied from 18.97 to 68.75, and were significantly higher in the UDPW than in the SSW (p<0.05). In order to explore the effect of AMF on weathering process, triangle maps were constructed to analyze the weathering characteristics of sediment samples with different GRSP concentrations. The results indicated that biologically AMF-mediated weathering in this area leads to the formation of clay minerals. Moreover, The CIA was significantly correlated with GRSP concentrations (r=0.43, p<0.01), and both the CIA and GRSP were significantly correlated with nutrient concentrations (SOC, TN, P, and Fe) (p<0.01). These results indicate that AMF excursions in wetland ecosystems enhance carbon sequestration and mineral weathering, and in turn they alter retention of at least some nutrients.
Nonideal Electric Field Observed in the Separatrix Region of a Magnetotail Reconnection Event
Authors: Yu Xiancai , Wang Rongsheng , Lu Quanming
Published: March 2020

The microphysics in the separatrix region (SR) plays an important role for the energy conversion in reconnection. Based on the Magnetospheric Multiscale observations in the magnetotail, we present a complete crossing of the current sheet with ongoing magnetic reconnection. The field‐aligned inflowing electrons were observed in both separatrix regions (SRs) and their energy extended up to several times of the thermal energy. Along the SR, a net parallel electrostatic potential was estimated and could be the reason for the inflowing electron streaming. In the northern SR, the electron frozen‐in condition was violated and nonideal electric field was inferred to be caused by the gradient of the electron pressure tensor. The nongyrotropic electron distribution and significant energy dissipation were observed at the same region. The observations indicate that the inner electron diffusion region can extend along the separatrices or some electron‐scale instability can be destabilized in the SR. 
Real-time earthquake hazard assessment based on high-rate GNSS PPPAR
Authors: Jiang Yang , Gao Yang , Sideris Michael
Published: March 2020

To provide hazard assessment in rapid or real-time mode, accelerations due to seismic waves have traditionally been recorded by seismometers. Another approach, based on the Global Navigation Satellite System (GNSS), known as GNSS seismology, has become increasingly accurate and reliable. In the past decade, significant improvements have been made in high-rate GNSS using precise point positioning and its ambiguity resolution (PPPAR). To reach cm-level accuracy, however, PPPAR requires specific products, including satellite orbit/clock corrections and phase/code biases generated by large GNSS networks. Therefore, the use of PPPAR in real-time seismology applications has been inhibited by the limitations in product accessibility, latency, and accuracy. To minimize the implementation barrier for ordinary global users, the Centre National D’Etudes Spatiales (CNES) in France has launched a public PPPAR correction service via real-time internet streams. Broadcasting via the real-time service (RTS) of the international GNSS service (IGS), the correction stream is freely provided. Therefore, in our work, a new approach using PPPAR assisted with the CNES product to process high-rate in-field GNSS measurements is proposed for real-time earthquake hazard assessment. A case study is presented for the Ridgecrest, California earthquake sequence in 2019. The general performance of our approach is evaluated by assessing the quality of the resulting waveforms against publicly available post-processing GNSS results from a previous study by Melgar et al. (2019), Seismol. Res. Lett. XX, 1–9, doi: 10.1785/ 0220190223. Even though the derived real-time displacements are noisy due to the accuracy limitation of the CNES product, the results show a cm-level agreement with the provided post-processed control values in terms of root-mean-square (RMS) values in time and frequency domain, as well as seismic features of peak-ground-displacement (PGD) and peak-ground-velocity (PGV). Overall, we have shown that high-rate GNSS processing based on PPPAR via a freely accessible service like CNES is a reliable approach that can be utilized for real-time seismic hazard assessment.
Intercomparison and validation of detected SST fronts based on CMEMS high-resolution reanalysis data and satellite observations in the South China Sea
Authors: Ren Shihe , Zhu Xueming , Marie Drevillon
Published: March 2020

Oceanic fronts, as important mesoscale phenomena, are transition zones between two water mass with different hydrological features, which has important significances in various fields, such as fishery, environment protection and marine military. In order to effectively obtain the ocean front information, a gradient-based Canny edge detection algorithm is applied to detect the ocean front, and post-processing procedure specifically designed for high resolution hindcast and reanalysis is utilized to extract primary ocean fronts, ensuring the balance of frontal continuity and positioning accuracy. Based on CMEMS reanlaysis and satellite SST data and regional model hindcast from NMEFC in China, a long-term intercomparison and validation is performed to evaluate the frontal detection method and model behavior in aspect of mesoscale forecasting/hindcasting. Frontal statistical product include mean status, seasonal and interannual analysis are utilized to intercompare. We also develop ‘CLASS 4’ validation metric to validate daily results in different datasets. Further more, forecast error, bias and skill of operational ocean front product are also shown for potential users.
The Interpretation of a Polarimetric Coherency Matrix with Four Scattering Models Considering Polarimetric Symmetry
Authors: An Wentao , Lin Mingsen
Published: March 2020

For a multi-look polarimetric synthetic aperture radar (POLSAR) image, each pixel corresponds to a polarimetric coherency matrix. Model-based incoherent polarimetric decomposition is a technique which is widely used to analyze multi-look POLSAR data. Traditional model-based incoherent polarimetric decomposition algorithms have some inherent drawbacks such as negative power components, polarimetric information loss, and non-model-based decomposition results. This study tries to completely interpret a polarimetric coherency matrix by the incoherent sum of four scattering mechanisms. Therefore, the proposed algorithm can be regarded as a new type of model-based incoherent polarimetric decomposition. All the four scattering models are firstly derived with polarimetric symmetry. The four scattering models correspond to surface scattering, double-bounce scattering, volume scattering and helix scattering, respectively. Then a new four-component model-based incoherent decomposition algorithm is found. After extracting the helix scattering component and the maximum possible volume scattering component, the remaining coherency matrix is decomposed into two components with an orientation angle difference of 45°. With the new algorithm, most pixels of a real POLSAR image can be completely decomposed into four components which are exactly consistent with helix scattering, volume scattering, surface scattering, and double-bounce scattering, respectively. Moreover, the proposed decomposition algorithm fully utilizes the polarimetric information, and all scattering component powers are nonnegative. Experiments with E-SAR, RADARSAT-2, and GF-3 data are presented to illustrate the effectiveness of analyzing the scattering mechanisms of real terrain targets with the proposed decomposition algorithm. The proposed decomposition algorithm is also compared with classic four-component model-based incoherent polarimetric decomposition algorithms.
Relationships between ground motion parameters and damaged buildings for 2016 Mw 6.4 Meinong, Taiwan Earthquake
Authors: Song Guan-Yi , Wu Yih-Min
Published: March 2020

The relationships between ground motion parameters (including peak ground acceleration, PGA; peak ground velocity, PGV) and building damages are crucial to estimate the possible seismic losses for future destructive earthquakes. One such relationship had been established based on the 1999 Chi-Chi earthquake (Mw=7.6). Since 2010, a new assessment system of seismic damaged buildings had been adopted in Taiwan. Damaged buildings are now classified into two categories, yellow-tagged buildings are amendable and red-tagged buildings may need to rebuild. Our main goal is to renew the relationship to better reflect the current status in Taiwan, both in the buildings and assessment system. 2016 Meinong earthquake (Mw=6.4) caused the most damaging buildings in Taiwan since 1999 Chi-Chi earthquake. It’s an opportunity to combine ground motion data with building assessments for the new regression relationship. From the results, we find out that in the Meinong earthquake, the PGA seems to possess a higher correlation to the building damages, contrary to the previous studies. Further investigation suggests that it may be due to the biased sample size to the damaged buildings, that is, most of the damaged buildings tend to be lower.

Keywords: Hazard analysis, Peak ground acceleration, Peak ground velocity, Seismic damage assessment
Substorm onset latitude and the steadiness of magnetospheric convection
Authors: Milan Steve , Carter Jenny , Walach Maria-Theresia , Sangha Harneet , Anderson Brian
Published: March 2020

We study the role of substorms and steady magnetospheric convection (SMC) in magnetic flux transport in the magnetosphere, using observations of field-aligned currents (FACs) by the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE).  We identify two classes of substorm, with onsets above and below 65o magnetic latitude, which display different nightside FAC morphologies.  We show that the low-latitude onsets develop a poleward-expanding auroral bulge, and identify these as substorms that manifest ionospheric convection-braking in the auroral bulge region.  We show that the high-latitude substorms, which do not experience braking, can evolve into SMC events if the interplanetary magnetic field (IMF) remains southwards for a prolonged period following onset.  Our results provide a new explanation for the differing modes of response of the terrestrial system to solar wind-magnetosphere-ionosphere coupling, as understood in the context of the expanding/contracting polar cap paradigm, by invoking friction between the ionosphere and atmosphere.
Belemnites, clumped isotopes and oxygen fractionation
Authors: Vickers Madeleine , Bernasconi Stefano , Ullmann Clemens , Hesselbo Stephen , Price Gregory , Korte Christoph
Published: March 2020

Belemnite calcite has been used extensively for Jurassic and Cretaceous stable oxygen isotope temperature reconstructions since the 1950s. However, with the advent of clumped isotope thermometry, a consistent offset between reconstructed δ18O temperatures vs Δ47 temperatures from the same belemnites has been observed. We investigate the causes of this offset by analyzing samples from the aragonitic phragmacone and calcitic rostrum from the same Cylindroteuthis belemnites, along with other aragonitic benthos, from the Callovian-aged Christian Malford Lagerstätte, U.K. Our new clumped isotope data suggest that the water-calcite 18O-fractionation factor in belemnite calcite was larger than that of the commonly used δ18O thermometry equations (e.g. Kim and O’Neil, 1997), and which is currently observed in other marine calcifiers. Our reconstructions suggest that the oxygen isotope fractionation is compatible with that observed in slow-forming abiotic calcites (e.g. Coplen, 2007) and in rapidly precipitating Travertines (Kele et al. 2015). The application of more established δ18O thermometry equations (Kim and O’Neil, 1997) to belemnite calcite for temperature reconstructions has resulted in a consistent underestimation of belemnite calcification temperatures, which has led to erroneous conclusions about belemnite life habits, and underestimation of global temperatures during these greenhouse times. We therefore advocate the use of calcite equations based on low precipitation rate experiments (e.g. Coplen, 2007; Kele et al., 2015) for belemnite rostra temperature reconstructions.
Seismic Microzonation using 6C Measurements
Authors: Keil Sabrina , Wassermann Joachim , Igel Heiner
Published: March 2020

Microzonation is one of the essential tools in seismology to mitigate earthquake damage by estimating the near surface velocity structure and developing land usage plans and intelligent building design. The number of microzonation studies increased in the last few years as induced seismicity becomes more relevant, even in low risk areas. While of vital importance, especially in densely populated cities, most of the traditional techniques suffer from different short comings. The microzonation technique presented here tries to reduce the existing ambiguity of the inversion results by the combination of single-station six-component (6C) measurements, including three translational and three rotational motions, and more traditional H/V techniques. By applying this new technique to a microzonation study in Munichs (Germany) inner city using an iXblue blueSeis-3A rotational motion sensor together with a Nanometrics Trillium Compact seismometer we were able to estimate Love and Rayleigh wave dispersion curves. These curves together with H/V spectral ratios are then inverted to obtain shear wave velocity profiles of the upper 100 m. The resulting 1D velocity profiles are used to estimate the local shaking characteristics in Munich. In addition, the comparison between the estimated velocity models and the borehole-derived lithology gives a positive correlation, indicating the applicability of our method.