bluuebunny/crossref_metadata_2025 huggingface dataset:
Target-oriented optimized survey design and quantitative comparison for 3D electrical resistivity tomography
Authors: Jiang Lincheng , Tian Gang , Wang Bangbing , Abd El-Raouf Amr
Published: March 2020

In recent decades, geoelectrical methods have played a very important role in near-surface investigation. The most widely used of these methods is electrical resistivity tomography (ERT). Regardless of the forward and inversion algorithms used, the original data collected from a survey is the most important factor for quality of the resulted model. However, 3D electrical resistivity survey design continues to be based on data sets recorded using one or more of the standard electrode arrays. There is a recognized need for the 3D survey design to get better resolution using fewer data. Choosing suitable data from the comprehensive data set is a great approach. By reasonable selecting, better resolution can be obtained with fewer electrodes and measurements than conventional arrays. Previous research has demonstrated that the optimized survey design using the 'Compare R' method can give a nice performance.

This paper adds target-oriented selection and modified the original 'Compare R' method. The survey design should be focused on specific target areas, which need a priori information about the subsurface properties. We select electrodes and configurations as the target set by the comprehensive set firstly which meets the requirements of the target area. The number of measurements and electrodes is much less than the comprehensive set and the model resolution matrix takes less time to calculate. At the next step for rank, we calculate the sensitivity matrix of the target set only once and then calculate the contribution degree of each measurement separately from it. The time of iterative calculation of the resolution matrix when measurements set changing is less than the original method.

The traditional method of evaluating RMS is not appropriate for comparing the quality of collected data by different survey designs. SSIM (structural similarity index) gives more reliable measures of image similarity better than the RMS. The curves of SSIM values in three dimensions and the average SSIM are given as quantitative comparisons. Besides, the frequency of electrodes utilized given to guides on selecting the highest used electrodes. Finally, the curves of the average relative resolution S and the number of electrodes as the number of measurements increase are given, which proves the method works effectively.

The results show the significance of using target-oriented optimized survey design, as it selects fewer electrodes and arrays than the original CR method. Also, it produces better resolution than conventional arrays and takes less calculation time. 3D SSIM, frequency of electrodes used, the relationship between average relative resolution, number of electrodes and number of measurements, these quantitative comparison methods can effectively evaluate the data collected in various survey designs.
Improving a continental hydrological model by enhancing its hydrological representation and implementing at 1km spatial resolution
Authors: Mateo Cherry May , Vaze Jai , Wang Biao
Published: March 2020

The Australian Water Resources Assessment Landscape (AWRA-L) model is a continental hydrological model developed by the Commonwealth Scientific and Industrial Research Organization (CSIRO) and Bureau of Meteorology (BoM) of Australia which is essential in providing consistent and reliable water resources assessments and accounts across continental Australia. The operational version of the AWRA-L model provides estimates of landscape runoff, evapotranspiration, soil moisture, and groundwater recharge/storage at a spatial resolution of 5km grids. Each 5km grid is assumed to have two hydrological response units (HRUs) – shallow-rooted vegetation and deep-rooted vegetation. To improve the landscape dynamics within the model, CSIRO and BoM increased the number of HRUs from two to five by representing the hydrological processes of the following: irrigated agricultural areas, perennial large water bodies, and impervious areas. The spatial resolution of the model was also increased to 1km grids to improve its applicability for management purposes in local areas.

In this presentation, a summary of the results of the improved model using the Murrumbidgee River as a test basin will be discussed. Overall, the results suggest that the incorporation of the extra HRUs enabled the explicit representation of hydrological processes in irrigated areas, large water bodies, and impervious areas. Particularly, significant improvement was seen in the comparison of the simulated soil moisture with the observed. With the implementation of the model at a finer 1km spatial resolution, the improved model can now provide more realistic estimates of the water balance which are more suitable for use in catchment and local scale applications.

To implement the improved model in other catchments within Australia as well as for the entire continent, numerous spatial data inputs to the model must be prepared. To ensure the reliability and consistency of the spatial data layers, the most recent and best available data were used to derive and regenerate the AWRA-L spatial input layers for the Australian continent. The 48 input spatial layers to the improved 5 HRU AWRA-L model have been updated and made available both at 5km and 1km spatial grids. The climatological inputs from 1970-2012 have also been prepared to match with the spatial grids of the AWRA-L model. The updated spatial layers will be shown in this presentation.  The updated input spatial layers are essential for implementing the improved AWRA-L model at any catchment within continental Australia. Local catchments with a high fraction of irrigated agricultural areas, impervious areas, or large water bodies will benefit the most from these updates. While the spatial layers were prepared for use in the AWRA-L model, they may also be useful for the development of large-scale hydrological models as well as to the hydrological community, in general.
Extreme precipitation increases plant biomass through altering nitrogen acquisition by grasses and soil microorganisms
Authors: Tian Yuqiang
Published: March 2020

Extreme precipitation events resulting from climate change have strong impact on structure and functions of grassland ecosystems. The extreme climate events may shift plant productivity and nutrient acquisition preferences by roots and microorganisms.We conducted an extreme precipitation simulation experiment and used in-situ 15N labeling of the three N forms to investigate N acquisition (N uptake rate, 15N recovery and preference for N form) by the dominant plant species Stipa grandis and soil microorganisms.Increased rain frequency raised the growth and N acquisition of S. grandis, while microbial N uptake remains unaffected. Microorganisms strongly outcompeted S. grandis for total 15N acquisition, however such superiority decreased in higher extreme precipitation frequency. Plant and microorganisms converged their N demands from distinct to similar preferences for N forms with high precipitation frequency. Such chemical niche partitioning by extreme precipitation effectively reduced root and microbial competition for each N form. Overall, important mechanistical insights into chemical niche differentiation by the effects of extreme climate events and their effects on structure, functions and plant-microbial interactions in temperate grasslands were explained.
Modeling guided waves to constrain the velocity structure of the oceanic crust in the subduction zone of eastern Alaska
Authors: Guan Xiaoyu , Zhou Yuanze , Furumura Takashi
Published: March 2020

Fitting subduction zone guided waves with synthetics is an ideal choice for studying the velocity structure of the oceanic crust. After an earthquake occurs in subduction zones, seismic waves can be trapped in the low-velocity oceanic crust and propagated as guided waves. The arrival time and frequency characteristics of the guided waves can be used to image the velocity structure of the oceanic crust. The analysis and modeling based on guided wave observations provide a rare opportunity to understand the velocity structure of the oceanic crust and the variations in oceanic crustal materials during the subduction process.

High-frequency guided waves have been observed in the subduction zone of eastern Alaska. On several sections, observed seismograms recorded by seismic stations show low-frequency (<2Hz) onsets ahead of the main high-frequency (>2Hz) guided waves. Differences in the arrival times and dispersion characteristics of seismic phases are related to the velocity structure of the oceanic crust, and the characteristics of coda waves are related to the distribution of elongated scatters in the oceanic crust. Through fitting the observed broadband waveforms and synthetics modeled with the 2-D FDM (Finite Difference Method), we obtain the preferred oceanic crustal velocity models for several sections in the subduction zone of eastern Alaska. The preferred models can explain the seismic phase arrival times, dispersions, and coda characteristics in the observed waveforms. With the obtained P- and S- wave models of velocity structures on several sections, the material compositions they represent are deduced, and the variations of oceanic crustal materials during subducting can be understood. This provides new evidence for studying the details of the subduction process in the subduction zone of eastern Alaska.
Future changes of summer monsoon characteristics and evaporative demand over Asia in CMIP6 simulations
Authors: Ha Kyung-Ja , Moon Suyeon , Timmermann Axel , Kim Daeha
Published: March 2020

Future greenhouse warming is expected to influence the character of global monsoon systems. However, large regional uncertainties still remain. Here we use 16 CMIP6 models to determine how the length of the summer rainy season and precipitation extremes over the Asian summer monsoon domain will change in response to greenhouse warming. Over East Asia the models simulate on average on the earlier onset and later retreat; whereas over India, the retreat will occur later. The model simulations also show an intensification of extreme rainfall events, as well as an increase of seasonal drought conditions. These results demonstrate the high volatility of the Asian summer monsoon systems and further highlight the need for improved water management strategies in this densely-populated part of the world.
Intra-annual variations of spectrally resolved gravity wave activity and observations of turbulence in the UMLT region
Authors: Sedlak René , Zuhr Alexandra , Hannawald Patrick , Schmidt Carsten , Wüst Sabine , Bittner Michael
Published: March 2020

Multi-year temperature time series from OH-airglow infrared (IR) spectrometers deployed at different sites in Europe as part of the Network for the Detection of Mesospheric Change (NDMC) are used to estimate the gravity wave activity in the upper mesosphere / lower thermosphere (UMLT) region.

The seasonal course of gravity wave activity is found to be strongly dependent on the wave period. While there is almost no clear variability of gravity wave activity for periods lower than about 60 minutes, we find strong evidence for an increasing variation throughout the year for periods longer than ca. 60 min. A dominant semi-annual structure with maxima at the solstices is found up to a periodicity of about 200 minutes, where a gradual transition to an annual cycle with maximum activity during winter and minimum activity during summer is observed.

The energy and momentum carried by gravity waves is dissipated in terms of turbulent wave breaking. Using observations of airglow imagers with high spatial and temporal resolution which were operated at the same time as the abovementioned IR-spectrometers we performed an investigation of turbulent gravity wave dynamics. The estimations of the turbulent eddy diffusion coefficient and the energy dissipation rate from the image series of a turbulent wave front agree quite well with the few available values in literature. A machine learning approach for the systematic extraction of turbulent episodes from the very large data set is presented.

This work received funding from the Bavarian State Ministry of the Environment and Consumer Protection.
Preliminary paleomagnetic results from PS97 cores from the Drake Passage for the past 110 ka
Authors: Liu Jiabo , Nowaczyk Norbert , Zheng Xufeng , Liu Qinsong , Arz Helge
Published: March 2020

Paleomagnetic records reconstructed from globally distributed marine sediments have greatly improved our understanding of long-term paleosecular variations and geomagnetic excursions. Nevertheless, questions regarding to the development of the geomagnetic field anomaly in the Southern Atlantic Ocean and the asymmetric geomagnetic field between Northern and Southern Hemispheres are not yet satisfactorily resolved. Paleomagnetic data, particularly from the Southern Hemisphere, is needed to better define the global geomagnetic field configurations spanning paleosecular variations and excursions. In this study, three sediment cores (PS97-085, PS97-84, PS97-079) recovered from the Drake Passage, Southern Ocean were subjected to detailed rock magnetic and paleomagnetic investigations. Preliminary age models were obtained by correlating their magnetic susceptibility to the ẟ18O master record from Dome C, Antarctica. In addition, rock magnetic records of the studied PS97 cores were further correlated to that of core PS67/197-1 with AMS 14C age constraints. The results from PS97 cores are thus continuously covering the past about 110 ka. Rock magnetic results indicate titanomagnetite is the dominant magnetic carrier in the studied PS97 cores. Relative paleointensities (RPI) derived from these PS97 cores are comparable with the regional relative paleointensity records and the South Atlantic paleointensity stack (SAPIS). Additionally, anomalous inclinations at about 41 ka and 35 ka, observed in core PS97-085, are coeval with the Laschamps and the Mono Lake excursions, respectively. This study provides new paleomagnetic records from the Southern Ocean, though further age constrains are needed to consolidate the paleomagnetic interpretations. The up to now obtained paleomagnetic records, together with previous studies from the Southern Ocean, are aiming to clarify the asymmetric pattern of non-dipole geomagnetic field between Northern and Southern Hemispheres.
Development and Application of Dynamic Water resources Asesment Tol (DWAT)
Authors: Jang Cheolhee
Published: March 2020

The Dynamic Water Resources Asesment Tol (DWAT) acounts for water balance on dynamic (hourly or daily) as wel as static (monthly or yearly) bases. It can be aplied to a smal or a mid-sized basin for water resources planing and management with consideration of surface water as wel as groundwater. The DWAT clasifies a watershed into hydrologicaly homogeneous sub-basins so that runof characteristics resulting from geomorphological factors can be objectively represented, and infiltration, evaporation and groundwater flows can be simulated acording to soil layers. In aditon, as the physical input parameters can be easily extracted by the GIS preprocesing module within the system, it can be aplied to areas in various hydrological, geophysical and climatic conditons, such as tropical, rural, forest or newly developed urban areas. The DWAT has ben developed in Korea Instiute of Civil Enginering and Building Technology (KICT) since 2012 as a part of WMO (World Meteorological Organization) RA (Regional Asociation) II WGHS (Working Group on Hydrological Services) and CHy (Commision for Hydrology) AWG (Advisory Working Group) activites, and it has ben suported by the Han River Flod Control Ofice, Ministry of Environment, Republic of Korea. The first version 1.0 beta of the DWAT was developed in the end of 2017, which contains sub-algorithms such as evapotranspiration, infiltration, watershed runof, groundwater flow, chanel routing and user convenience systems. In the midle of 2018, the second version 1.0 was developed with the aditon of rice pady field, snowmelt and manual/automatic parameter optimization modules. In May 2019, the third version of 1.1 was developed in consideration of the recommendations made by the WMO panel of experts.

Acknowledgements

 This research is supported by the Research Program (20200041-001) of Korea Institute of Civil Engineering & Building Technology

 
Lithospheric density structure of the Southern Central Andes and their forelands constrained by 3D gravity modelling
Authors: Rodriguez Piceda Constanza , Scheck-Wenderoth Magdalena , Gómez Dacal Maria Laura , Bott Judith , Prezzi Claudia , Strecker Manfred
Published: March 2020

The Andean orogeny is a ~7000 km long N-S trending mountain range developed along the South American western margin. The formation of this mountain range is driven by the subduction of the oceanic Nazca plate beneath the continental South American plate, being the only known present-day case of subduction-type orogeny. In this tectonic setting, the intrinsic physical properties of the overriding plate govern the formation of zones of crustal strength and weakness and control the localization and the style of deformation. Furthermore, the dynamics of the subducting oceanic lithosphere is strongly conditioned by the properties of the continental counterpart. The southern segment of the Central Andes (29°S-39°S) is a suitable scenario to investigate the relationship between the two plates for several reasons. It is characterized by a complex deformation pattern with variations in horizontal shortening, crustal thickening and mean topographic elevation. In addition, the subduction angle changes at 33°S-35°S latitude from flat in the North to normal in the South. To gain insight into this geodynamic system, a detailed characterization of the lithosphere is needed. Therefore, we constructed a 3D model of the entire segment of the Southern Central Andes that is consistent with the available geological, seismic and gravity data in order to assess the geometry and density variation within the lithosphere. The derived configuration shows a spatial correlation between density domains and known tectonic features. It is also consistent with other independent observations such as S wave velocity variation and surface deformation. The generated structural model allows us to reach the first conclusions about the relationship between the characteristics of the overriding plate and the crustal deformation and dynamics of the subduction system. It is also useful to constrain thermomechanical experiments and therefore contributes to discussions about the crustal thermal and rheological fields within the region.
High-frequency Sequence stratigraphy and facies architecture in Cholan Formation (Pleistocene), northwestern Taiwan: the evolution of a foreland basin
Authors: Zhu Xiao-Cheng , Chen Wen-Shan
Published: March 2020

In northwestern Taiwan, Cholan Formation in Dahan river is about 1400 m thick that contains high-frequency sequence stratigraphy (6th-order) and detail of facies architecture which indicates evolution of the foreland basin. In late Miocene (6 Ma), the Taiwan orogeny belt is formed by the arc-continental collision (the Luzon Volcanic Arc and the Eurasian plate). During Pliocene-Pleistocene, uplift of the Hsueshan Range and the Western Foothill created by a series of the fold-thrust belt formed the foreland basin. Most importantly, high subsidence rate and high sedimentation rate are critical that glacio-eustasy (6th-order) could be correlated to parasequences in Cholan Formation. It provides a precise age model to discuss different stages of foreland basin.

Parasequences in Cholan Formation could be divided into three types of depositional systems including siliciclastic shallow marine (Type 1), margin marine (Type 2) and nonmarine (Type 3) that are a typical sequence of foreland basins. Type 1, which is tidal-dominated open coast, shows 10-30 m coarsening-upward succession. Type 2, which is tidal-dominated delta, shows two different parts. The lower part is 10-50 m coarsening-upward succession which unconformity contact with Type 1. The upper part changes to 20-50 m fining-upward succession. Type 3, which is alluvial system, shows 30-70 m fining-upward succession that is conformable with Type 2. From shallow marine to nonmarine, the thickness of parasequence is growing thicker that indicates long-term tectonic subsidence rate is getting higher with more sediment deposits in the basin. In more detail, in marine setting, sea level change is the main considered factor to identify sequence boundary (SB) and maximum flooding surface (MFS), while in nonmarine setting, precipitation change in glacial and inter-glacial may be a critical factor to impact the formation of SB. However, MFS is complicated to define because some parasequences show tidal signal, but some don’t. It could be influenced by degree of sea level uplift or paleotopography. In Cholan Formation, the signal of sea level, tectonic and climate is sensitive to reflect in stratigraphy architecture.

Keywords: Foreland basin, High-order sequence stratigraphy, Marine to nonmarine facies architecture
Best practices in cooperation between authorities and geoscientists to serve society and ensure adequate protection of our palaeontological heritage
Authors: DeMiguel Daniel , Strani Flavia , Azanza Beatriz , Meléndez Guillermo
Published: March 2020

The geosciences have experimented recently the urgent necessity to count on practitioners who possess an ethical conscience and the desire to act responsibly and serve the society. This is especially necessary in the case of our paleontological heritage. Fossils are natural objects resulting from natural processes that connect us with our natural environments and, also importantly, with our origins and past. The paleontological heritage is therefore strongly linked with our natural, social and cultural heritage, and cannot be interpreted or studied without this synergetic perspective. Transmitting paleontological knowledge to geoscientists (including educators) and authorities, especially based on the findings from the fossil record, must be pivotal in order to ensure adequate protection and conservation of the paleontological heritage, promote responsible research practices and attract attention by society.

An ethical and correct management of the paleontological heritage often raise key ethical concerns. There are a range of useful examples concerning i) the increasing use of technological advances and an ambitious development of infrastructures (e.g., mining activities and exploitation of georesources, railroad, highway and residential projects, etc.) often initiated, funded, and influenced by government agencies or public and/or private organizations; ii) individual actions to collect the most spectacular, relevant fossils related to both commercial or collecting, or simple vandalism; and iii) the increasing use of fossils in paleontological research, didactic and touristic activities and exhibitions—and its profound impact on sites and fossils, that relate to our paleontological heritage and can thus foster personal growth, enrich citizens´ knowledge and promote (and improve) interaction between society and this field of geosciences.

More specifically, in Spain there are examples and case studies in the field of geoscience that illustrate how to gain awareness and knowledge about geoethical conflicts between works of infrastructures, and the geoconservation of paleontological sites and the discovery of new fossils, with benefits for society, the administration, and the scientific community.

Identifying and considering ethical issues and dilemmas associated to these topics in paleontology are important for both ethical (adhering to general principles or conceptions of what is right and wrong) and practical reasons. As such, geoscientists who are more aware of their ethical and social responsibilities concerning our paleontological heritage will be better able to put their knowledge at the service of society and to help increase public trust in geosciences.
Moho depth determination in the Eastern Alps-Pannonian basin-Carpathian mountains region based on H-K grid search method and CCP migration of receiver functions
Authors: Kalmár Dániel , Hetényi György , Bondár István ,   AlpArray Working Group
Published: March 2020

We perform P-to-S receiver function analysis to determine a detailed map of the crust-mantle boundary in the Eastern Alps–Pannonian basin–Carpathian mountains junction. We use data from the AlpArray Seismic Network, the Carpathian Basin Project and the South Carpathian Project temporary seismic networks, the permanent stations of the Hungarian National Seismological network, stations of a private network in Hungary as well as selected permanent seismological stations in neighbouring countries for the time period between 2004.01.01. and 2019.03.31. Altogether 221 seismological stations are used in the analysis. Owing to the dense station coverage we can achieve so far unprecedented resolution, thus extending our previous work on the region. We applied three-fold quality control, the first two on the observed waveforms and the third on the calculated radial receiver functions, calculated by the iterative time-domain deconvolution approach. The Moho depth was determined by two independent approaches, the common conversion point (CCP) migration with a local velocity model and the H-K grid search. We show cross-sections beneath the entire investigated area, and concentrate on major structural elements such as the AlCaPa and Tisza-Dacia blocks, the Mid-Hungarian Fault Zone and the Balaton Line. Finally, we present the Moho map obtained by the H-K grid search method and pre-stack CCP migration and interpolation over the entire study area, and compare results of two independent methods to prior knowledge.
Comparing two location estimates of the same seismo-acoustic event. A survey of available statistical tools.
Authors: Le Bras Ronan , Qorbani Ehsan
Published: March 2020

The Comprehensive Nuclear-Test-Ban Treaty (CTBT) calls for a verification regime which involves interactions between the International Data Centre (IDC) component of the Provisional Technical Secretariat (PTS) established in Vienna, Austria, and the National Data Centres (NDC) of Member States of the Treaty. The results of location estimates of the same event by the two organizations is obtained using similar methods and software but potentially involve different seismo-acoustic networks and therefore a direct comparison of the distances and time differences is not sufficient and the different error estimates for the event should be taken into account. Most methods of location are using iterative linear inversions and the probability distributions are Gaussian, using the covariance matrix resulting from the last step of the iterative inversion process as the parameters of the Gaussian distributions. We explored the statistical tools available to compare two multi-dimensional distributions and measure a distance between them in an objective manner, including the Hellinger distance, the Bhattacharyya distance, and the Mahalanobis distance and we will show examples of application to the seismo-acoustic location problem. 
Characteristics of natural neutron radiation background performed within the BSUIN project.
Authors: Jedrzejczak Karol , Kasztelan Marcin , Szabelski Jacek , Tokarski Przemysław , Orzechowski Jerzy , Marszał Włodzimierz , Przybylak Marika
Published: March 2020

The BSUIN (Baltic Sea Underground Innovation Network) aims to enhance the accessibility of the underground laboratories in the Baltic Sea region for innovation, business and science. One of the BSUIN project activities is characterization of natural background radiation (NBR) in underground facilities. A specific type of NRB is neutron radiation, whose measurement requires specific instruments and long-term exposure in-situ, in heavy underground conditions.

In this talk the method of natural neutron radiation background will be presented as well as results of pilot measurements in several underground locations. In order to make this measurements, a measuring setup was designed and made. The setup design is closely matched to the task: the setup is scalable in a wide range, completely remotely controlled (via the Internet) and capable of long-term operation (months).

The pilot measurements were performed in Callio Lab, Pyhäsalmi, Finland, (4100 m w.e.), in Reiche Zeche mine in Freiberg, Germany (410 m w.e.) and in Experimental Mine “Barbara” in Mikołów, Poland (100 m w.e).
Upscaling of geomechanical properties in Discrete Element Method (DEM) models of volcano-tectonics
Authors: Harnett Claire , Holohan Eoghan , Thomas Mark , Schöpfer Martin
Published: March 2020

In volcanology, as in other branches of geosciences, uncertainties exist around how well rock properties constrained on the laboratory scale represent those at the field scale. For volcano deformation, scale-related uncertainties are compounded by changes in geomechanical properties as progressive deformation evolves to large strains. Furthermore, such large strain deformation is often localised along large-scale discontinuities. It is therefore difficult to investigate this deformation by using traditional continuum modelling approaches. Here we provide an overview of recent Discrete Element Method (DEM) modelling results as applied to large strain, edifice-scale deformation phenomena, such as lava dome instability and caldera collapse. The DEM is a particle-based numerical modelling approach that enables simulation of strain localisation and highly discontinuous deformation.

Upscaling the geomechanical properties of volcanic rocks from the laboratory to the field can be achieved in DEM models through a calibration process that simulates both the laboratory rock testing and field-scale examples. For lava dome collapse, through comparison of observed and modelled attributes (e.g., displacement, dome growth), we infer that field-scale bulk rock properties (i.e., strength, elastic moduli) are approximately 30% of typical laboratory-scale properties. For caldera collapse, varying the same geomechanical properties produces a range of observed styles of caldera collapse, but the properties required at the edifice scale are approximately a factor of 10 lower than typical laboratory-scale properties. Both the calibration of geomechanical properties and the structural outcomes of DEM simulations, and hence the accuracy of upscaling, are fundamentally dependent on the model resolution, which is a function of both the particle size and distribution. The chosen resolution particularly affects rock strength, fracture toughness, and crack development and propagation. Nonetheless, previously reported discrepancies between seismic and geodetic moments for certain volcano-tectonic events are consistent with the upscaled geomechanical properties in edifice-scale DEM simulations, in that such discrepancies can be explained by a similar-sized reduction in the properties derived from laboratory-scale rock tests.  
The Western Tibetan Vortex as an emergent feature of near-surface temperature variations
Authors: de Kok Remco , Immerzeel Walter
Published: March 2020

Glaciers are growing in a part of High Mountain Asia (HMA), contrary to the demise of glaciers worldwide. A proposed explanation for this behaviour is the decreasing strength of the "Western Tibetan Vortex" (WTV), a circular motion of air in the troposphere around northwestern High Mountain Asia, which is proposed to drive near-surface temperatures. Here, we show that the WTV is the change of wind field resulting from changes in near-surface temperature, and that it is not unique to northwestern HMA, but is generally applicable to large parts of the globe. Instead, we argue that net radiation is likely the main driver of near-surface temperatures in Western HMA in summer and autumn, and that the WTV is the response of the atmosphere to changes in temperature. The decreasing strength of the WTV, as seen during summer in the 20th century, is thus likely the result of changing net radiation, and not the main driver of cooling itself. We do argue that the WTV is a useful concept to understand large scale climate variability in the region, and that such an approach could yield important insights in other mid-latitude regions as well.
Resolution Dependency of Future Caribbean Sea Level Response
Authors: van Westen René , Dijkstra Henk
Published: March 2020

The current global climate models, which are often used in inter-comparison projects, have a large variety in their spatial resolution. For most climate models, the resolution of the ocean grid does not allow to resolve mesoscale processes such as ocean eddies. Current sea level projections are based on these coarse climate models, but might have biases (either positive or negative) in these projections since mesoscale processes are parameterised.

Here we investigate the differences in future Caribbean sea level rise using a centennial simulation of a high- and low-resolution version of the Community Earth System Model under the same anthropogenic forcing. In the high-resolution version of the model mesoscale processes are resolved. Locally, we find a decrease of 7.2 cm in sea level extremes over a 100-year period in the high-resolution version; this decrease is almost absent in the low-resolution version. This local decrease in sea level extremes is related to ocean eddies, which are not resolved in the low-resolution version, hence explaining the different sea level response between the models. When comparing modelled sea level trends to observed sea level trends over the past 25 years, we find a reasonable agreement between observations and the high-resolution model. However, for the low-resolution model and some of the preliminary CMIP6 model output, there is a substantial mismatch between the observed- and modelled sea level trends.

By analysing model output from two different resolutions of the same climate model, we find that the sea level response in the Caribbean Sea is resolution-dependent. As a result, not resolving mesoscale processes in climate models can locally result in overestimations of future sea level rise projections.
A CrIS Cloud Detection Method Based on CrIS and ATMS Measurements
Authors: Guan Li , Xue Qiumeng
Published: March 2020

The Suomi National Polar-orbiting Partnership (SNPP) satellite carrying the Cross-track Infrared Sounder (CrIS) and the Advanced Technology Microwave Sounder (ATMS) instruments can provide high quality hyperspectral infrared (IR) data and microwave (MW) measurements. It is very important to ensure the accuracy of cloud detection in the infrared hyperspectral measurements before they are used for geophysical retrievals or data assimilation. Therefore, a cloud detection method using the CrIS hyperspectral radiances at longwave (709.5-746.0 cm-1) and shortwave (2190-2250 cm-1) bands and the ATMS measurements is introduced in this paper. Four steps are included in this algorithm: identifying clear FOV, estimating the number of cloud formations, thermal contrast, and cloud mask classification. Specifically, each CrIS field-of-view (FOV) is preliminarily assigned as clear or cloudy by comparing the measured IR radiances and simulated IR clear radiances which are generated from the MW-retrieved geophysical state vector based on a physical inversion method. Secondly, the number of cloud formations within one CrIS field-of-regard (FOR) is estimated using the principal component analysis (PCA). Next, CrIS radiances at longwave channels and shortwave bands are used to evaluate the thermal contrast within the FOR. Based on the above informations each FOR will finally be assigned a cloud mask classification. The cloud mask results derived from this technique are also analyzed.
Overview on the spectral combination of integral transformations
Authors: Pitoňák Martin , Šprlák Michal , Novák Pavel , Tenzer Robert
Published: March 2020

Geodetic boundary-value problems (BVPs) and their solutions are important tools for describing and modelling the Earth’s gravitational field. Many geodetic BVPs have been formulated based on gravitational observables measured by different sensors on the ground or moving platforms (i.e. aeroplanes, satellites). Solutions to spherical geodetic BVPs lead to spherical harmonic series or surface integrals with Green’s kernel functions. When solving this problem for higher-order derivatives of the gravitational potential as boundary conditions, more than one solution is obtained. Solutions to gravimetric, gradiometric and gravitational curvature BVPs (Martinec 2003; Šprlák and Novák 2016), respectively, lead to two, three and four formulas. From a theoretical point of view, all formulas should provide the same solution, but practically, when discrete noisy observations are exploited, they do not.

In this contribution we present combinations of solutions to the above mentioned geodetic BVPs in terms of surface integrals with Green’s kernel functions by a spectral combination method. We investigate an optimal combination of different orders and directional derivatives of potential. The spectral combination method is used to combine terrestrial data with global geopotential models in order to calculate geoid/quasigeoid surface. We consider that the first-, second- and third-order directional derivatives are measured at the satellite altitude and we continue them downward to the Earth’s surface and convert them to the disturbing gravitational potential, gravity disturbances and gravity anomalies. The spectral combination method thus serves in our numerical procedures as the downward continuation technique. This requires to derive the corresponding spectral weights for the n-component estimator (n = 1, 2, … 9) and to provide a generalized formula for evaluation of spectral weights for an arbitrary N-component estimator. Properties of the corresponding combinations are investigated in both, spatial and spectral domains.

 
Reclaimed wastewater to irrigate olive groves and vineyards: effects on soil properties
Authors: Mañas Ramírez Pilar , De las Heras Ibañez Jorge , Peña Molina Esther
Published: March 2020

Having drinking water is one of the sustainable development goals (SDG no. 6) that is not always easy to ensure, especially in countries like Spain or arid regions marked by water deficit. The reuse of treated water should be considered when planning water resources, but it is necessary to conduct experiments to verify that this effectiveness is applicable to real situations. Our field trial was carried out in several study areas distributed in agricultural parcels of SE Spain. Three olive grove and vineyard plantations were monitored for 3 years. Two irrigation water types were considered: freshwater from conventional wells (controls) and treated wastewater (TW). The treated wastewater came from three different wastewater treatment plants (WWTP) that employ a biological secondary treatment without disinfection and different numbers of Inhabitants Equivalent (IE) as a measure of pollutant load. They were located in Valdeganga (3,000 IE), Fuenteálamo (5,600 IE) and Ontur (1,500 IE). All the study plots were watered by drip irrigation using 16 mm-diameter polyethylene pipelines.

Several soil and water parameters were analysed to determine the main differences among them. Increasing of soil salinity is a real risk after irrigating with wastewater as is reflected in higher electrical conductivity values. However, this fact was compensated by the greater contribution of organic matter and nutrients, which allowed crops to adequately develop. Moreover, no microbiological, metal content, toxicity or organic compounds in the studied water samples were detected and reclaimed municipal wastewater was comparable in quality to the conventional sources at all the demonstration sites. Hence adopting this water type for irrigation for grapes and olives could help save primary water resources. The future of water resources management policies involves sustainable wastewater reuse within a circular economy frame because this is the only way to guarantee everyone solidarity access to water.

Fundings provided by the ERA-NET WaterWorks2014 Cofunded Call. This ERA-NET is an integral part of the 2015 Joint Activities developed by the Water Challenges for a Changing World Joint Programme Initiative (Water JPI).
Synchrotron X-ray imaging for characterizing chrysotile asbestos
Authors: Ricchiuti Claudia , Bloise Andrea , Lanzafame Gabriele , Punturo Rosalda
Published: March 2020

Over the last decades, rocks containing Naturally Occurring Asbestos (NOA) have been widely studied by many authors with the aim of determining the potential health risks to exposed neighboring populations. It is difficult to accurately characterize the asbestos fibres contained within the rocks as conventional techniques are not effective and have drawbacks associated with the disturbance of the sample under study. Indeed, the size and geometric shape ratios of asbestos chrysotile fibres can be subjected to change, thus leading to the misevaluation of asbestiform fibre findings. In this frame, our study aims to determine the characteristics of the veins that form in serpentinite (i.e. shape) and their infill (i.e. size of fibres), without grinding and/or particle size reduction.

To obtain this ambitious goal, X-ray synchrotron microtomography (SR-μCT) supplemented with polarized light microscope (PLM), scanning electron microscopy analysis combined with energy dispersive spectrometry (SEM/EDS), electron probe micro-analysis (EPMA) were used for identifying asbestos fibres in a mineral matrix. In the specific case, we analyzed a representative set of veins and fibrous chrysotile that fills the veins, taken from massive serpentinite outcrops (Southern-Italy; Bloise and Miriello, 2008). The non-destructive SR-μCT technique allowed to identify respirable chrysotile fibres (regulated asbestos) within the serpentinite matrix and to reconstruct the 3D structures of infill chrysotile asbestos fibres as well as other phase, whose structures were not resolvable with PLM, SEM or EPMA. Moreover, due to differences in chemical composition between veins and matrix, the obtained data enabled to evaluate the vein shapes present in the massive serpentinite matrix. In particular, iron and aluminum distribution variations between veins and matrix induce different radiation absorption patterns, thus permitting a detailed image-based 3D geometric reconstruction (Bloise et al., 2019). The results proved that SR-μCT is a valuable and promising technique for analyzing asbestos chrysotile that fills the veins within massive serpentinite. The 3D images of veins may help to identify NOA contained within serpentinite rocks.

References:

Bloise, A., Miriello, D., 2018. Multi-analytical approach for identifying asbestos minerals in situ. Geosci. 8 (4), 133. https://doi.org/10.3390/geosciences8040133.

Bloise, A., Ricchiuti, C., Lanzafame, G., Punturo, R., 2019. X-ray synchrotron microtomography: a new technique for characterizing chrysotile asbestos, Sci. Total Environ. https://doi.org/10.1016/j.scitotenv.2019.135675
Primary Organic Aerosol Source Identification and Aging Observed by Hourly Measurements of Organic Molecular Markers in Urban Shanghai, China
Authors: Wang Qiongqiong , He Xiao , Zhou Min , Huang Dandan , Qiao Liping , Zhu Shuhui , Ma Ying-ge , Wang Hong-li , Li Li , Huang Cheng , Xu Wen , Worsnop Douglas , Goldstein Allen H. , Guo Hai , Yu Jian Zhen
Published: March 2020

Molecular markers in ambient organic aerosol (OA) are valuable in providing source information and insights to formation process of OA. Their traditional quantification is based on offline analysis of filter samples, hugely hindering the utility of the tracer data due to the coarse time resolution and labor-intensive nature. In this study, hourly organic molecular markers in fine particulate matter were measured using a recently commercialized Thermal desorption Aerosol Gas chromatography-mass spectrometry (TAG) at an urban location in Shanghai, China during a three-week campaign from 9 November-3 December 2018. Anhydro sugars, fatty acids, aromatic acids, and polycyclic aromatic hydrocarbons (PAHs) were examined in detail. Their diurnal variations showed characteristic features representing the corresponding emission source activities. For example, stearic acid showed a clear peak around 7 pm, in accordance with the enhanced cooking activities during mealtime. Diagnostic ratios of related maker species of different reactivity provided unique information in uncovering the source information and tracking evolution of OA in the atmosphere. For example, Levo/Manno and Levo/K+ ratio analysis identified crop residue burning as the major form of biomass burning. Ratios of unsaturated and saturated fatty acids gave unambiguous indication of atmospheric degradation of unsaturated fatty acids after emissions. Furthermore, oleic acid to stearic acid ratio was highly correlated with O/C ratios, suggesting the possible utility of oleic acid as a model compound to examine the heterogeneous reaction of cooking-related OA. PAH ratio-ratio plots helped tag varying influences of major combustion sources associated with air masses of different origins, with coal combustion and biomass burning dominant under the influence of long range transport air mass and vehicle emissions dominant under local/median range air mass influence. This study demonstrated the utility of the hourly organic markers in capturing the dynamic change of the source emissions and atmospheric ageing, providing observational evidence to support their use in rapid source apportionment.