Hasil untuk "Geology"

Wang Li, Xuxuan Ma, Roberto Weinberg et al.

Abstract The formation, storage, and evolution of granitic magmas are fundamental processes driving the growth of continental crust. While traditionally attributed to crystal fractionation in high‐melt fraction magma chambers, the model invoking low‐melt fraction crystal mushes has gained wide acceptance. However, the chemical and textural impacts of crystal mush rejuvenation remain elusive and the precise petrological record is relatively poorly studied. The rapakivi K‐feldspar identified in the early Eocene monzogranitic porphyry of the Caina intrusive complex, Gangdese batholith, is an ideal candidate for investigating these issues, as feldspar can record clues to magmatic processes. Field survey, optical and mineral flake scanning observations, X‐ray fluorescence analysis, in situ Sr and mineral Sm‐Nd isotopic analyses, TESCAN integrated mineral analysis, electron probe microanalysis, and three‐dimensional crystal shape modeling were performed on the collected samples. K‐feldspars can be divided into three types based on chemical zonation: normal, reverse, and oscillatory zoning crystals. Varying isotopic signatures between the K‐feldspar and associated mantle suggest that the rapakivi texture originated in heterogeneous magmatic pulse recharge. Crystal shape modeling of the plagioclase chadacryst, mantle, and matrix plagioclase, combined with compositions, indicates that mantle plagioclase originated from the quenching of recharge magmas. We propose a model for the formation of rapakivi K‐feldspar and the rejuvenation of crystal mush. Repeated hot magma pulses recharged the mush, triggering magma convection and thermal perturbations. This process enabled the prolonged growth of K‐feldspar megacrysts, which were subsequently capped by plagioclase, resulting in the formation of the rapakivi texture.

V. M. Usova

Background. African rift basins area characterized by changes from exclusively or predominantly gas to oil specialization, depending on the age of the deposits and moving away from the Southern and Western centers of the African superplume. A model accounting for changes in the conditions of hydrocarbon generation in peri- and intracontinental rift basins due to the cooling of asthenospheric rift-forming flows, upon their moving away from the hot plume centers, is proposed.Aim. To determine regional geological patterns of the oil and gas specialization of rift basins and their probable nature.Materials and methods. The study involved a comparative analysis of published data on the geology and oil and gas potential of rift basins (intra- and pericontinental) using seismic tomography data on the temperature state of the deep subsoil of Africa and the adjacent ocean areas.Results. The oil and gas specialization of rift basins was shown to correlate with their age, tectonic development, and position in the modern structure of Africa, as well as with the distance from the Southern and Western centers of the African superplume.Conclusion. The significant importance of the superplume in determining the oil and gas specialization of basins is substantiated.

Chun-Wei Huang, Si Ying Yau, Chiao-Ling Kuo et al.

Study region: The Choushui River Fan, Taiwan. Study focus: Groundwater overdraft has led to not only groundwater depletion but also environmental disasters, such as subsidence and seawater intrusion in the Choushui River Alluvial Fan, Taiwan. The influence of land subsidence is gradually shifting from the coast to the center of the fan and threatening Taiwan high-speed rail. However, it remains a great challenge to manage and model the groundwater aquifer due to numerous unregulated wells. This study maps and locates private wells using deep learning technologies. We trained and validated convolutional-based deep learning neural networks (DNNs), using street view images. We applied the DNNs to a land subsidence area along the Taiwan high-speed rail, termed the Golden Corridor in Taiwan. The results showed that DNNs can recognize pumping wells with at least 90% accuracy. The testing cases showed their capability to recall all the pumping wells in three road segments along the Golden Corridor. Finally, we spatially estimated potential pumping of a subsidence area using the fine-trained DNNs. New hydrological insights for the region: Given the prevalence of unknown private pumping in the Choushui River Fan, our image data-driven computer vision approach not only eases labor-intensive private well investigations but also advances hydrologic understanding for groundwater modeling. We enhance comprehension of unknown sinks and provide their spatial distribution to improve groundwater modeling.

Tobias Blanke, Holger Born, Bernd Döring et al.

Abstract This paper introduces three novel approaches to size geothermal energy piles in a MILP, offering fresh perspectives and potential solutions. The research overlooks MILP models that incorporate the sizing of a geothermal borefield. Therefore, this paper presents a new model utilizing a g-function model to regulate the power limits. Geothermal energy is an essential renewable source, particularly for heating and cooling. Complex energy systems, with their diverse sources of heating and cooling and intricate interactions, are crucial for a climate-neutral energy system. This work significantly contributes to the integration of geothermal energy as a vital energy source into the modelling of such complex systems. Borehole heat exchangers help generate heat in low-temperature energy systems. However, optimizing these exchangers using mixed-integer-linear programming (MILP), which only allows for linear equations, is complex. The current research only uses R-C, reservoir, or g-function models for pre-sized borefields. As a result, borehole heat exchangers are often represented by linear factors such as 50 W/m for extraction or injection limits. A breakthrough in the accuracy of borehole heat exchanger sizing has been achieved with the development of a new model, which has been rigorously compared to two simpler models. The geothermal system was configured for three energy systems with varying ground and bore field parameters. The results were then compared with existing geothermal system tools. The new model provides more accurate depth sizing with an error of less than 5 % compared to simpler models with an error higher than 50 %, although it requires more calculation time. The new model can lead to more accurate borefield sizing in MILP applications to optimize energy systems. This new model is especially beneficial for large-scale projects that are highly dependent on borefield size.

Yu Tan, Guangping Zhou, Huyuan Zhang et al.

Experiments were conducted to evaluate the healing of drying cracks in air-dried bentonite-sand blocks after hydration and swelling in groundwater, providing justifications to simplify the protection of blocks prior to installation in a high-level radioactive waste repository. Synthetic groundwater was prepared to represent the geochemistry of Beishan groundwater, and was used to hydrate the blocks during the swelling pressure and swelling strain measurements, as Beishan is the most promising site for China's repository. Healing of the surface cracks was recorded by photography, and healing of the internal cracks was visualized by CT images and hydraulic conductivity of air-dried blocks. The results indicate that the maximum swelling pressure and swelling strain are primarily affected by the geochemistry of Beishan groundwater, but not affected by the drying cracks. The maximum swelling pressure and swelling strain of air-dried blocks are comparable to or even higher than the pressure and strain of fresh blocks. The maximum swelling pressure measured in strong (i.e. high ion strength) Beishan groundwater was 44% of the pressure measured in deionized (DI) water, and the maximum swelling strain was reduced to 23% of the strain measured in DI water. Nevertheless, the remained swelling of the blocks hydrated in strong Beishan groundwater was sufficient to heal the surface and internal drying cracks, as demonstrated by the pictures of surface cracks and CT images. The hydraulic conductivity of the air-dried block permeated with strong groundwater was comparable (3.7× higher) to the hydraulic conductivity of the fresh block, indicating the self-healing of drying cracks after hydration and swelling in groundwater. A simplified method of protecting the block with plastic wraps before installation is recommended, since the remained swelling of the block hydrated in Beishan groundwater is sufficient to heal the drying cracks.

Daxing WANG, Haiyan HU, Jiaqun ZOU et al.

Objective To explore the enrichment conditions and main controlling factors of shale gas in the Lower Wuerhe Formation of the Permian System in the Junggar Basin, the Lower Wuerhe Formation in the Dongdaohaizi Sag was selected as the research object. Methods Based on the data of outcrop, core, well logging, well-calibrated seismic reflections and the technologies of total organic carbon (TOC) content determination, whole-rock X-ray diffraction, gas adsorption (N2, CO2), the distribution characteristics, organic matter development characteristics, reservoir characteristics, and gas bearing characteristics of the Lower Wuerhe Formation shale were studied. Results The results show that: (1) The organic matter of the Lower Wuerhe Formation shale is dominated by Ⅱ2 and Ⅲ types and shows an average TOC content of 1.58%. The average vitrinite reflectance (Ro) of organic matter is 1.46%, which indicates the mature stage. The average thickness of the source rock is 75 m. Summarily, the source rock is good and has a high gas potential. The basin simulation results show an average shale gas content of 1.89 m3/t in the Lower Wuerhe Formation. (2) The pores and microfractures in shale reservoirs are highly developed, and gas is primarily adsorbed in micropores and mesopores. The average porosity and permeability are 6.10% and 0.27×10-3 μm2 respectively, which are favourable for shale gas accumulation. (3) The shale has a high clay mineral content, with an average of 29.6%, providing a significant specific surface area and enhancing the gas adsorption capacity of the shale. Additionally, the average brittle mineral content is 50.9%, indicating good frackability. (4) Moreover, the shale reservoir exhibits a relatively large pressure coefficient of 1.58, indicating the favourable conservation conditions. The analysis of the regional tectonic-sedimentary environment and geochemical parameters indicates that the main factors controlling shale gas accumulation in the Lower Wuerhe Formation of the Dongdaohaizi Sag are geochemical parameters and preservation conditions. The key factors influencing shale gas accumulation include the high thermal evolution maturity of organic matter, large shale thickness, high TOC content, and good preservation conditions. These conditions suggest that the favourable area for shale gas exploration and development in the Dongdaohaizi Sag is located in the northeastern slope area of the sag's abdomen. Conclusion The results of this research reveal the enrichment conditions and main controlling factors of shale gas in the Lower Wuerhe Formation in the Dongdaohaizi Sag, which has reference value for deep oil and gas exploration in the abdominal area of the Junggar Basin.

U. Nanni, U. Nanni, D. Scherler et al.

<p>Accurate measurements of ice flow are essential to predict future changes in glaciers and ice caps. Glacier displacement can in principle be measured on the large scale by cross-correlation of satellite images. At weekly to monthly scales, the expected displacement is often of the same order as the noise for the commonly used satellite images, complicating the retrieval of accurate glacier velocity. Assessments of velocity changes on short timescales and over complex areas such as mountain ranges are therefore still lacking but are essential to better understand how glacier dynamics are driven by internal and external factors. In this study, we take advantage of the wide availability and redundancy of satellite imagery over the western Pamirs to retrieve glacier velocity changes over 10 d intervals for 7 years and for a wide range of glacier geometry and dynamics. Our results reveal strong seasonal trends. In spring/summer, we observe velocity increases of up to 300 % compared to a slow winter period. These accelerations clearly migrate upglacier throughout the melt season, which we link to changes in subglacial hydrology efficiency. In autumn, we observe glacier accelerations that have rarely been observed before. These episodes are primarily confined to the upper ablation zone with a clear downglacier migration. We suggest that they result from glacier instabilities caused by sudden subglacial pressurization in response to (1) supraglacial pond drainage and/or (2) gradual closure of the hydrological system. Our 10 d resolved measurements allow us to characterize the short-term response of glaciers to changing meteorological and climatic conditions.</p>

Mengdi CHEN, Zhenjiao JIANG, Chenchen HUO

Hydraulic conductivity in sandstone-type uranium-bearing formations is of high heterogeneity. However, restricted by the means of test and analysis, it is difficult to accurately describe the heterogeneous coefficient of permeability, which results in the deviation in the prediction of in-situ leaching uranium mining process and limits the fine control of in-situ leaching uranium mining process. To solve this problem, a random characterization method of heterogeneous parameter distribution of an ore bed is proposed in this paper. On this basis, water salt coupling numerical random simulation is carried out to reveal the internal migration process and influence range of leaching agent reservoir caused by pumping and injection of multiple wells under the conditions of different spatial distribution of coefficient of permeability. The application results in a uranium deposit in Inner Mongolia show that the coefficient of permeability increases along the direction of regional groundwater flow, which is conducive to the evacuation of the injected leaching agent. On the contrary, the leaching agent is prone to the aggregation effect. After identifying and verifying the boundary conditions of the model with groundwater level monitoring data, the diffusion rate of the solution is 210 m2/d under the assumption of homogeneity, and the diffusion area of the 20-year mining cycle is 1.53 km2. Considering the heterogeneity of the ore bed and the uncertainty of parameters, the expansion rate of the leaching agent area is predicted to be 191−228 m2/d, and the diffusion area of the leaching agent is 1.47−1.74 km2. Compared with the assumption of homogenization, the uncertainty of the diffusion rate and diffusion area of the leaching agent is 17.62% and 17.65%. Considering the heterogeneity and uncertainty of coefficient of permeability, the prediction results of leaching agent migration and transformation behavior are more representative, which provides a more reliable reference for the design of in-situ leaching uranium mining scheme and the development of sandstone type uranium resources.

Farouk I. Metwalli, Amir Ismail, M.S. Metwally et al.

The present study aims to integrate a large set of geological and geophysical data into a comprehensive model describing the depositional features of the Abu Madi/El Qar'a/Khilala gas fields. The model is based on the sequence stratigraphic framework of the Abu Madi Formation defined using cores, well logs, and time-migrated seismic data. Seismic trace attribute sections and relative acoustic impedance sections are also used. A possible depositional pattern for the main Level III is established, based on the lithological and petrophysical information derived from the seismic data analysis. The Abu Madi Formation can be regarded as a depositional sequence recording the progressive drowning of the incised valley. The sequence is bounded at the base by an erosional unconformity, created by a drop in the level of the Late Messinian Sea, and at the top by a drowning unconformity related to the Early Pliocene transgression. The bottom of Level II divides the Abu Madi sequence into two smaller sequences. In both sequences, gas-bearing traps can be found in the Lowstand Systems Tracts, represented by the fluvial Level III and fluvial-deltaic Level II, respectively.

Emilio Herrero-Bervera, Mario Moreira

In order to understand further the emplacement (i.e., volcanic growth) of 22 Icelandite and 3 Rhyodacite cooling units in one of the long volcanic sequences known as Mauna Kuwale of the Wai’anae volcano (ca. 3.3 Ma), Oahu Hawaii we have conducted appropriate rock magnetic experiments described below as well as anisotropy of magnetic susceptibility (AMS) studies of such 25 units. We have undertaken rock magnetic investigations such as continuous and partial thermo-magnetic cycles of low field magnetic susceptibility versus temperature dependence, (k-T) curves experiments. We classified the k-T heating-cooling dependence of susceptibility in three groups A, B and C. Type A: yielded two components of titano-magnetite with a predominat Ti rich phase and occasionally a relevant magnetite component phase. Type B: samples are characterized by Ti poor magnetites. Magnetite dominates as the main magnetic carrier. Type C: k-T curves show one single phase of titanomagnetite, and Ti poor magnetite. The coercivity or remanence, determined by back field magnetization is always <60 mT, which suggest the predominance of magnetic components of low coercivity, like magnetite. Usually, two coercivity components are identified in the specimens. In addition we also conducted magnetic granulometry analyses on 27 specimens to determine the domain state of the flows. The ratio of hysteresis parameters (Mr/Mrs versus Hcr/Hc) show that overall samples fall in the Pseudo-Single Domain (PSD) region with high values of Mr/Mrs and very low values of Hcr/Hc. Only two samples from cooling units 17 and specially 22 show a Single Domain (SD) magnetic behavior and a sample from one unit approaches the SD-MD mixture region. We measured the magnetic susceptibility of all cooling units and we found out that in all analyzed units the magnetic susceptibility is low 13.7 ± 8.8 (10⁻³ SI). Magnetic anisotropy/magnetic fabric is used as a tool in rock fabric analyses to investigate the preferred orientation of magnetic minerals in rocks. Magnetic anisotropy is low on all (measured) flows from the Icelandite cooling units from 1 to 17 (mean P’ = 1.010), but becomes noticeably distinct and high in rhyodacite cooling units 23, 24 and 25 (mean P’ = 1.074). Four units show a magnetic fabric with k₃ axes vertical to sub-vertical which may be denoted as normal for the horizontal to sub horizontal units. Two Icelandite cooling units display oblate shapes and two other cooling units triaxial shapes. K₁ axes are horizontal but point in different directions, i.e., NE and NW. Remaining cooling units show different magnetic fabric. Units 17, 23, 24 and 25, despite important variations in anisotropy (low for units 25 and high for units 23 and 24) and shape of ellipsoid (oblate in cooling unit 23, prolate in 24 and triaxial in 25) the k₃ axes show the same orientation, SW to SSW dipping around 45° and a very steady magnetic lineation azimuth NW nearly horizontal to sub horizontal. The magnetic mineralogy and magnetic fabric indicate that both the Icelandite and Rhyodacite cooling units the magmatic evolution during the shield stage of the entire Wai’anae volcano and that such growth was not affected by tectonic deformation.

HOU Dali, HAN Xin, TANG Hongming, GUO Jianchun, GONG Fengming, SUN Lei, QIANG Xianyu

Adsorbed gas represents a primary mode of shale gas occurrence and is a major source of shale gas production in the later stages of development. It primarily resides within the organic kerogen and clay minerals of shale formations, with organic kerogen being the dominant host. Consequently, the study of organic kerogen characteristics and its adsorption mechanisms is crucial for understanding shale gas development. In this paper, the kerogen of Longmaxi Shale in the Sichuan Basin is taken as the research object. The microstructure of kerogen is expressed by combining methods through the solid-state NMR experiment, Fourier transform infrared spectroscopy experiment, X-ray photoelectron spectroscopy experiment, and the molecular structure model of kerogen is constructed. The adsorption mechanism and characteristics of CH4 in kerogen of Longmaxi Shale are analyzed by magnetic levitation weight experiment, molecular simulation methods of the Grand Canonical Monte Carlo（GCMC）, and Molecular Dynamics（MD）. The results show that the molecular formula of the kerogen of shale experimental sample of Longmaxi Formation is C237H219O21N5S4. The excess adsorption gas volume of CH4 in kerogen increase first and then decreased with the increase of pressure. Under the same pore size and pressure, the excess adsorption gas volume and total gas volume of CH4 decrease with the increase in temperature. The C and S atoms in kerogen are the main cause of CH4 adsorption. The CH4 near the kerogen pore wall presents an adsorption state, while the CH4 far from the kerogen pore wall presents a free state. As the pore size increase, the distance between the two peaks of CH4 density gradually increases, and the peak value decreases gradually.

Arifah, Darmawan Salman, Amir Yassi et al.

Bulukumba Regency is one of the major rice-producing areas in South Sulawesi, Indonesia and has experienced frequent climate disasters over the past decade. Several downstream villages within the Bettu River irrigation area have been affected by the drought, culminating in reduced lowland rice production and increasing the vulnerability of farmers’ livelihoods. This study aims to evaluate the vulnerability of the livelihood system among rice farmers in the Bettu River irrigation area by classifying the area into two zones based on the distance from the main irrigation canal, namely the upstream area and downstream area. The livelihood vulnerability index (LVI) framework and livelihood vulnerability index-Intergovernmental Panel on Climate Change (LVI-IPCC) approach were applied by selecting geographic and socio-demographic indicators that affected the farmer households, including 8 major components and 26 sup-components. The data for LVI-IPCC estimation were collected by randomly selecting 132 households from villages in the two areas. The empirical results showed that farmers in the downstream area were more vulnerable to climate change than farmers in the upstream area. The major components causing the livelihood vulnerability of the downstream farmers were livelihood strategy, food, water, land, health, as well as natural disasters and climate variability. In particular, the sub-components of agricultural livelihood diversification, consistent water supply for farming, and drought events were important in the downstream area. Farmers in the upstream area were vulnerable to socio-demographic profile and social network components. The LVI-IPCC findings suggested that the government should prioritize farmers in the downstream area to develop resilience strategies, particularly by increasing irrigation infrastructure and the number of reservoirs and drilling holes. Furthermore, to increase their adaptive capacity in terms of diversification of agricultural livelihood systems, the government and donor agencies need to provide trainings on the development of home food industries for poor farmers and vulnerable households that were affected by disasters.

Ling Chen, Xu Wang, Xin Wang et al.

Studying the structures, properties and origins of the Earth's internal discontinuities is an important part in the efforts to understand the physical and chemical properties of the layered Earth, as well as to explore the dynamic processes and driving mechanisms of plate tectonics and the whole Earth system. Receiver function imaging is a well-known and widely-adopted seismological method in extracting the structural information of the Earth's internal discontinuities, and has become an indispensable tool to investigate the layering in structure and composition, and the thermal states and deformation behaviors of the crust and upper mantle, lithosphere-asthenosphere, mantle transition zone, and even shallow part of the lower mantle in the deep Earth. Since the receiver function method was proposed about half a century ago, great progress has been made in both methodology and application, targeting to subsurface structures of various spatial scales and from one- to three-dimension. In particular, with more and more seismic arrays being deployed in global and regional scales, and the continuous advancement of computing power and imaging theory during the last two decades, receiver function imaging has only become more powerful to constrain the subsurface structures. In this paper, we first briefly review the development history of the receiver function method. After introducing the basic principles involved, we then outline the major progress made during the last two decades in both methodology and application of this method, including but not limited to receiver function construction and forward modeling, receiver functions analysis for complex media or detailed discontinuity structures (e.g., anisotropy, dipping structures, irregular topography, sharpness of discontinuities), ray and wave-equation based receiver function migration in imaging crustal and upper mantle discontinuities, velocity inversion of receiver functions as well as its combination with other types of data. We focus mainly on the following three aspects: deconvolution techniques to construct receiver functions, imaging of discontinuity structures and inversion of velocity structures using receiver functions, with specific emphasis on the recent advances, challenges, and possible solutions. In the light of the emerging and future trends in seismology, we finally discuss the directions of receiver function studies from the viewpoints of both methodology and application.

A. Geiss, S. J. Silva, S. J. Silva et al.

<p>Recent advances in deep convolutional neural network (CNN)-based super resolution can be used to downscale atmospheric chemistry simulations with substantially higher accuracy than conventional downscaling methods. This work both demonstrates the downscaling capabilities of modern CNN-based single image super resolution and video super-resolution schemes and develops modifications to these schemes to ensure they are appropriate for use with physical science data. The CNN-based video super-resolution schemes in particular incur only 39 % to 54 % of the grid-cell-level error of interpolation schemes and generate outputs with extremely realistic small-scale variability based on multiple perceptual quality metrics while performing a large (<span class="inline-formula">8×10</span>) increase in resolution in the spatial dimensions. Methods are introduced to strictly enforce physical conservation laws within CNNs, perform large and asymmetric resolution changes between common model grid resolutions, account for non-uniform grid-cell areas, super-resolve lognormally distributed datasets, and leverage additional inputs such as high-resolution climatologies and model state variables. High-resolution chemistry simulations are critical for modeling regional air quality and for understanding future climate, and CNN-based downscaling has the potential to generate these high-resolution simulations and ensembles at a fraction of the computational cost.</p>

Petros Petrounias, Panagiota P. Giannakopoulou, Aikaterini Rogkala et al.

This study was based on the reduction of the extraction of natural resources and, at the same time, was focused on the use of by-products and various wastes in construction applications by following the principles of circular economy. Sterile natural rocks (limestones, basalts), industrial by-products (slags), hotel construction wastes (bathroom wastes) and electronic wastes (e-wastes) were tested for pervious concrete aggregates. For this reason, ten concrete specimens were prepared and tested petrographically, structurally, and physically. The physical properties of the tested raw materials directly depended on their petrographic characteristics and played crucial role for the permeability of the produced concrete specimens, for their mechanical behavior, and for the freeze–thaw test results. Generally, from this study, strong encouraging results were achieved as concrete made by variable wastes and by-products can be compatible for concrete production as they show similar performance both in the mechanical strength test and in the freeze–thaw test with those made by natural aggregates. Another goal of this study was to recommend to other researchers the extended use of by-products, construction wastes, and e-wastes as concrete aggregates for producing eco-friendly constructions.

Ying Zhang, Zhengqiang Li, Yuanyuan Wei et al.

Following the accelerated development of urbanization and industrialization, atmospheric particulate matter has become a significant threat to public health globally. Environmental health studies usually use the mass concentration of fine particles (PM2.5) as a base data to predict the health risks of particulate exposure. However, PM2.5 data from ground monitoring stations in China has not been provided until January 2013 by the Ministry of Environmental Protection of China. Hence, an alternative dataset of PM2.5 spatiotemporal distributions extending to years earlier than 2013 is urgently needed, which is of great significance to atmospheric environment assessment and pollution prevention and control. Atmospheric aerosol products by the moderate-resolution imaging spectroradiometer (MODIS) have been released since 2000, which provides the possibility to reconstruct historical PM2.5. However, most current methods do not have the ability to estimate PM2.5 mass concentration independently of ground observations. The PM2.5 mass concentration data set produced by PM2.5 remote sensing (PMRS) model based on physical processes does not depend on the ground observations, and also is not affected by the uncertainty of model emission sources or the completeness of chemical reaction mechanism. These ensure that the point-by-point validation for PM2.5 mass concentration data is more convincing, and the dataset can also be further used for model assimilation and artificial intelligence training to improve their predictions. In this study, we calculate the monthly PM2.5 mass concentration near the ground over land of China using aerosol inversion products (aerosol optical depth and fine-mode fraction) of MODIS and meteorological data (boundary layer height & relative humidity) provided by the Modern-Era Retrospective Analysis for Research and Applications Version 2 (MERRA-2) data set. The results show that, in China, 6 pollution centers mainly concentrated in the central and eastern regions. The highest PM2.5 mass concentration occurred in winter, whereas the pollution range was larger in summer. There are 63.4% of validation sites with biases within ±20 μg m−3, and the expected error is as ±(15 μg m−3 + 30%) enveloped by the monthly mean PM2.5 mass concentrations. The monthly PM2.5 is stored as NETCDF format, with a spatial resolution of 1°×1°. The published data is available in http://www.dx.doi.org/10.11922/sciencedb.j00076.00061.

Belinda Gallardo, Alexandra Zieritz, David C Aldridge

Human activities such as transport, trade and tourism are likely to influence the spatial distribution of non-native species and yet, Species Distribution Models (SDMs) that aim to predict the future broad scale distribution of invaders often rely on environmental (e.g. climatic) information only. This study investigates if and to what extent do human activities that directly or indirectly influence nature (hereafter the human footprint) affect the global distribution of invasive species in terrestrial, freshwater and marine ecosystems. We selected 72 species including terrestrial plants, terrestrial animals, freshwater and marine invasive species of concern in a focus area located in NW Europe (encompassing Great Britain, France, The Netherlands and Belgium). Species Distribution Models were calibrated with the global occurrence of species and a set of high-resolution (9×9 km) environmental (e.g. topography, climate, geology) layers and human footprint proxies (e.g. the human influence index, population density, road proximity). Our analyses suggest that the global occurrence of a wide range of invaders is primarily limited by climate. Temperature tolerance was the most important factor and explained on average 42% of species distribution. Nevertheless, factors related to the human footprint explained a substantial amount (23% on average) of species distributions. When global models were projected into the focus area, spatial predictions integrating the human footprint featured the highest cumulative risk scores close to transport networks (proxy for invasion pathways) and in habitats with a high human influence index (proxy for propagule pressure). We conclude that human related information-currently available in the form of easily accessible maps and databases-should be routinely implemented into predictive frameworks to inform upon policies to prevent and manage invasions. Otherwise we might be seriously underestimating the species and areas under highest risk of future invasions.

H. Nagamoto, T. Fukushima, Y. Ida et al.

The data on radio telemetry links (for water information) at VHF/UHF in Hokkaido are used to investigate the rate of disturbances on radio links (or connection failure) and its association with a huge earthquake, Tokachi-oki earthquake on 26 September 2003. Especially, the telemetry links at the Tokachi region closest to the earthquake epicenter, showed a significant increase in disturbances on radio links two weeks to a few days before the earthquake on the basis of analysis during a long interval from 1 June 2002 to 3 November 2007 (over 5 years). We suggest that these severe disturbances in VHF/UHF telemetry links are attributed to the generation of seismogenic VHF/UHF radio noises (emissions). Based on this idea, we have estimated that the intensity of these seismogenic emissions is on the order of 10–19 dB μV/m. Finally, the present result was compared with other physical parameters already obtained for this earthquake.

J. Dilip Kumar, P. Reddy Prasad, B. Krishna Priya et al.

A procedure was developed for the determination of Sm, Eu and Yb in water samples by inductively coupled plasma-optical emission spectrometry (ICP-OES) after preconcentration on synthesized 5-(4-pyridyl azo)-8-quinolinol supported by Borassus flabellifer inflorescence (BFI). The sorbed element was subsequently eluted with 0.4 M HNO3 and the acid eluates were analyzed by ICP-OES. Under the optimal conditions, Sm, Eu and Yb in aqueous samples were concentrated 100-fold. Recoveries were obtained by the proposed method in the range of 98.6 -99.8%. This method was also applied for the analysis of spiked and natural water samples. The results provide strong evidence to support the hypothesis of an adsorption mechanism.