bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphometric Analysis of Koyna-Warna Region Seismicity
Authors: Arora Kusumita , Srinu Y. 
Published: December 2021

Abstract
After sixty years of studies of the reservoir triggered earthquakes in the Koyna-Warna region, several questions remain unanswered. In particular, the role of reservoir water on the seismicity, the area of influence and possible pathways through which surface water may catalyze an earthquake at depth, continues to be an enigma. On the basis of the high resolution DEM derived from airborne LiDAR data, several aspects of surface features have been unraveled. The characteristics of surface morphology over the region have been revealed. Lineament systems have been delineated, the association of which with subsurface trends and seismicity patterns, establish them as fault systems. We also attempt to look at geomorphic parameters over the region and investigate their correlation with seismicity. We find that earthquake clusters are associated with regions of tectonic control, the signatures of which differ in the Koyna and Warna regions.
Radon Monitoring in Artesian Wells at Mato-san Area of South Taiwan for Mud Eruption Studies
Authors: Kumar Arvind , Walia Vivek , Lin Shih-Jung , Fu Ching-Chou 
Published: December 2021

Abstract
In the present study, radon monitoring in the artesian wells of Mato-san areas of south Taiwan were carried out to know the working of the mud eruption and the dependence of the eruption cycle with radon changes. Radon monitoring in water was carried out by using RAD7. Water samples were collected at different depths from different wells for the period of two weeks to one month. This study shows that anomalous radon value has been observed before and after to some eruptions during the study periods. The opposite radon behaviors at well No. 2 and well No. 3(B) were observed during the eruption. Noted behavior of these wells may be due to the movement of gas fluxes during the eruption period.
Developing an Earthquake Resilient Society in the Vicinity of Himalaya
Authors: Gupta Harsh K. , Sabnis Kanchan A. 
Published: December 2021

Abstract
Among the seismically active continental regions, the Himalayan region is very significant with large human population in the immediate vicinity. The Himalayan region experienced four great earthquakes of M ~8 within a short span of 55 years from 1897 to 1952. The region has not experienced an earthquake of similar magnitude since 1952. Developing an earthquake resilient society through the process of developing earthquake scenarios, as to what would be the impact if one of the past earthquakes repeats today, is an extremely useful approach. And sharing this information with all concerned, doing the needful to educate and enrich the concerned government departments, and making the public a share-holder, helps. The 1905 Kangra earthquake of M ~ 8 had claimed ~ 20,000 human lives in addition to causing widespread damage. A scenario was built by the National Disaster Management Authority (NDMA), Government of India, as to what would be the consequences if such an earthquake occurred today? It was discovered that ~ 0.9 million human lives would be lost in the states of Punjab, Haryana, Himachal Pradesh and the Union Territory of Chandigarh if this earthquake occurred in the middle of the night. A year-long phase of training and educating at various levels to develop an earthquake resilient society in the states of Punjab, Haryana, Himachal Pradesh and the Union Territory of Chandigarh during 2012-2013 culminated in a mega mock drill on the 13 February 2013. It demonstrated what all had been achieved and what was missing. Encouraged by the success a similar exercise was carried out for the repeat of the 1897 Shillong earthquake for 8 northeast Indian states during 2013-2014 culminating in mega mock drills on 10 and 13 March 2014. In this communication a brief of these exercises is provided.
Influence of proppant physical properties on sand accumulation in hydraulic fractures
Authors: Li Jiangtao , Wei Jianguang , Zhou Xiaofeng , Zhang Ao , Yang Ying , Wang Anlun , Shang Demiao , Rong Gen 
Published: December 2021

AbstractThe proppant accumulation form in fractures is related to the formation conductivity after fracture closure, also closely related to the production rate of oil/gas wells. In order to investigate the influence of proppant physical properties on sand accumulation in fractures, a particle–fluid coupling flow model is established based on the Euler two-fluid model. Geometric parameters of a fracture in tight oil wells are approximately scaled in equal proportion as the physical model, which is solved by the finite volume method. And the model accuracy is verified by comparing with the physical experimental simulation in the literature. Results show that the higher proppant concentration corresponds to the faster particle sedimentation rate, and the greater sand embankment accumulation as well. However, the fluid viscosity will increase, inhibiting proppant migration to the deep part of the fracture. Reducing proppant density and particle size will enhance the fluidization ability of particles, which is conducive to the migration to the deep fracture at the initial stage of pumping. But, it is not beneficial to have a desirable accumulation state in the middle and later pumping stage, so it is difficult to obtain a higher comprehensive equilibrium height.
Traffic incident detection based on a global trajectory spatiotemporal map
Authors: Liang Haoxiang , Song Huansheng , Yun Xu , Sun Shijie , Wang Yingxuan , Zhang Zhaoyang 
Published: December 2021

AbstractTraffic incidents endanger the smooth running of vehicles. Congestion caused by traffic incidents has caused a waste of time and fuel and seriously affected transportation efficiency. At present, most methods use manual judgment or image features to detect traffic incidents, but these methods lack timeliness, leading to secondary incidents. For dangerous road sections such as ramp-free and long downhills, this paper proposes an algorithm to quickly detect traffic incidents based on a spatiotemporal map of vehicle trajectories. First, a vehicle dataset from the monitoring perspective is constructed, and an improved YOLOv4 detection algorithm is used to detect images organized as batches. Based on the detection result, the multi-object tracking method of vehicle speed prediction in key frames is used to obtain the vehicle trajectory. Then according to the vehicle trajectory obtained in a single scene, the vehicle trajectory is reidentified and associated in the continuous monitoring scene to construct a long-distance vehicle trajectory spatiotemporal map. Finally, according to the distribution and generation status of the trajectory in the spatiotemporal map, traffic incidents such as vehicle parking, vehicle speeding, and vehicle congestion are analyzed. Experimental results show that the proposed method greatly increases the speed of vehicle detection and tracking and obtains high mAP, MOTA, and MOTP indicators. The global spatiotemporal map constructed by trajectory reidentification can achieve high detection rates for traffic incidents, reduce the average elapsed time, and avoid the problems of the inaccuracy of analyzing image features.
Ground GNSS Station Selection to Generate the Global Ionosphere Maps Using the Information Content
Authors: Wang Sicheng , Huang Sixun , Fang Hanxian 
Published: December 2021

AbstractMore and more satellite constellations and ground receivers are available all over the world, and they can provide rich ionospheric remote sensing data sources. Due to the fact that different analysis centers use different generation techniques and different ground stations, their routinely released Global Ionosphere Maps (GIMs) have some differences. To study the problems of how many stations and which stations should be optimally chosen to generate the GIMs, a step‐by‐step iterative method based on the information content is proposed under the framework of 3DVAR data assimilation. This method adopts the information content to qualitatively evaluate the information contribution of a measurement to the reconstructed GIM, and selects the ground station with a maximum information content in every iteration. About 500 ground receivers from the International GNSS Services networks and Multi‐GNSS Experiment networks are collected from DOY 001 to DOY 120 in 2018 to demonstrate the feasibility of this method. The results show that the information contribution from the first 100 selected stations is over 70%, and the information contribution from the first 200 chosen stations is up to 87%. When the station selection criterion is taken as 95% of the total information content, nearly 300 stations are needed to reconstruct each GIM. Moreover, the quantitative information contribution from GPS, GLONASS, GALILEO, and BEIDOU satellite constellations is preliminarily analyzed.
Geophysical Research on Rock Mass Quality Evaluation for Infrastructure Design
Authors: Hasan Muhammad , Shang Yanjun , Shao Peng , Yi Xuetao , Meng He 
Published: December 2021

AbstractEvaluation of rock mass quality is necessary for the proper design of engineering infrastructures. Rock quality designation (RQD) is an important geotechnical parameter in the rock mass quality classification. However, given the limited data and natural heterogeneity, rock mass quality evaluation is a challenging task. Traditionally, the rock mechanical parameters are obtained from the drilling tests. However, the drilling tests only provide single‐point information and thus cannot provide detailed underground information. Moreover, boreholes are costly and time‐consuming, and still cannot be carried out in the steep topographic terrains. Alternatively, electrical resistivity tomography (ERT) is non‐invasive, cost‐effective, and user‐friendly, can provide 2D plane information even 3D information, and can bridge gaps between the available well data and the accurate subsurface geological model. In this research, we establish important empirical relations between ERT and the limited borehole data. We estimated RQD along with the ERT profiles and evaluated the subsurface for rock mass quality even where no borehole exits. Furthermore, the ambiguity of water/clay distinction in the geological model was removed via integration between ERT and induced polarization. Compared with the past geotechnical studies, our work provides far better insights into the subsurface via 2D/3D evaluation of rock mass quality for the development of the engineered structures. Therefore, geophysical research based on ERT can be very helpful in the hard rock terrains lacking sufficient mechanical well data.
Investigation of Springtime Cloud Influence on Regional Climate and Its Implication in Runoff Decline in Upper Colorado River Basin
Authors: Lin Yun , Takano Yoshihide , Gu Yu , Wang Jingyu , Zhao Bin , Liou Kuo‐Nan , Fu Rong 
Published: December 2021

AbstractThe subseasonal features of the annual trends of runoff and other associated hydroclimatic variables in the upper Colorado River basin (UCRB) are examined using multiple data sets from in situ observations, reanalysis, and modeling for early spring (February, March, and April), given that about 58% of annual mean runoff decline from 1980 to 2018 stem from its decreases in the three months. Our analysis suggests that the strong annual trends of hydroclimatic variables in March are more statistically significant than other two months. While recent observational studies attribute the decline of runoff for either annual total or cool and warm seasons to regional warming and precipitation decrease, we suggested, for the first time, that a larger decreasing trend of the runoff in March is caused by the declining cloud optical depth which induces further decrease in precipitation and additional increase in temperature on top of climatic warming. The extra warming can reduce available water resource in the basin likely by enhancing evaporation in March. The recent cloud suppression likely results from stronger subsidence and larger moisture flux divergence over southwestern United States because of abnormal circulation patterns in varying climate, in turn leading to drier atmosphere which is unfavorable for cloud formation/development over the UCRB region. The cloud influence on the runoff in March in the UCRB revealed in this study implies the importance of understanding subseasonal variations of hydroclimate in the changing climate, as well as a need of future studies on the response of circulation patterns to climate change at subseasonal level and its implication on local hydroclimate.
Detection of Polar Mesospheric Clouds Utilizing Himawari‐8/AHI Full‐Disk Images
Authors: Tsuda T. T. , Hozumi Y. , Kawaura K. , Tatsuzawa K. , Ando Y. , Hosokawa K. , Suzuki H. , Murata K. T. , Nakamura T. , Yue J. , Nielsen K. 
Published: December 2021

AbstractWith the objective of advancing the polar mesospheric cloud (PMC) detection capability by the Advanced Himawari Imager (AHI) onboard the Japanese geostationary‐Earth‐orbit (GEO) meteorological satellite Himawari‐8, a novel two‐step PMC detection technique applied to the Himawari‐8/AHI full‐disk images has been developed. The two‐step approach is dividing the PMC detection into stronger (the first step) and weaker (the second step) signals and enhances the detection capability while significantly decreasing the false PMC detections. The improved PMC sensitivity by Himawari‐8/AHI is comparable with the Cloud Imaging and Particle Size (CIPS) onboard the Aeronomy of Ice in the Mesosphere (AIM) satellite. With this encouraging result, PMC observations from Himawari‐8/AHI provide an additional extensive data set to the aeronomy and space science community.
Empirical Models of Ion Density Distribution in the Dayside Martian Ionosphere
Authors: Huang J.‐P. , Cao Y.‐T. , Cui J. , Hao Y.‐Q. , Wu X.‐S. , Wan X. , Li Q.‐L. , Zhong J.‐H. , Wei Y. 
Published: December 2021

AbstractWith the aid of the recent Neutral Gas and Ion Mass Spectrometer (NGIMS) measurements made onboard the Mars Atmosphere and Volatile Evolution spacecraft, we construct empirical models for the vertical density distributions of 12 species in the dayside Martian ionosphere over the altitude range of 150–450 km, from abundant species such as , , and O+ to trace species such as and OCOH+. Two different sets of formulism are proposed to parameterize the ion density distribution characterized either by a distinctive layer structure or by a near exponential decay above 150 km. Both the solar control and magnetic control of ion distribution are taken into account in our modelings. In general, our empirical models are in good agreement with the NGIMS measurements. The full set of parameters constrained by data‐model comparison is tabulated for reference. This allows the easy computation of any individual ion density profile for a unique combination of solar zenith angle, solar extreme ultraviolet flux, and ambient magnetic elevation, which in turn facilitates comparisons with photochemical model results. The empirical models reported in this study are an extension of previous empirical models constructed for the electron distribution in the dayside Martian ionosphere using both radar sounding and radio occultation data.
On the Interplay Between Solar Wind Parameters and ULF Wave Power as a Function of Geomagnetic Activity at High‐ and Mid‐latitudes
Authors: Dimitrakoudis Stavros , Mann Ian R. , Balasis Georgios , Papadimitriou Constantinos , Anastasiadis Anastasios , Daglis Ioannis A. 
Published: December 2021

AbstractUsing ground magnetometer measurements from the IMAGE array over the timespan of one solar cycle, we apply wavelets to statistically assess the power of ultra‐low frequency (ULF) waves from L = 3.34 to L = 13.6 as a function of Kp, solar wind speed (), solar wind dynamic pressure (), Dst, and . We find that although geomagnetic storms account for the overwhelming majority of ULF wave power at mid latitudes, this effect decreases for higher L‐shells. We present analysis of the effect of interplanetary magnetic field (IMF) on ULF wave power for different values of Kp and , revealing a strong inter‐dependency especially in relation to . A parameterization additionally incorporating appears to be more important at large‐L. Further, analysis for positive reveals a perhaps unexpected additional dependence on which points to effects of the interplanetary magnetic field cone angle and Kelvin‐Helmholtz instabilities. Finally, we derive ULF wave radial diffusion coefficients from the measured ULF wave power spectral densities and briefly discuss their importance for radiation belt dynamics. Interestingly, in part because of the correlation between Dst‐defined storm times and high Kp, we find that the low‐Kp radial diffusion coefficients during storms are higher than previously assumed almost certainly because of the dominance of nonstorm epochs in the statistics of median ULF wave power under conditions of low Kp. These inter‐dependencies should be taken into account in future specification models for ULF wave radial diffusion coefficients when applied in storm time simulations.
Ionospheric Disturbances and Irregularities During the 25–26 August 2018 Geomagnetic Storm
Authors: Astafyeva E. , Yasyukevich Y. V. , Maletckii B. , Oinats A. , Vesnin A. , Yasyukevich A. S. , Syrovatskii S. , Guendouz N. 
Published: December 2021

AbstractWe use ground‐based (GNSS, SuperDARN, and ionosondes) and space‐borne (Swarm, CSES, and DMSP) instruments to study ionospheric disturbances due to the 25–26 August 2018 geomagnetic storm. The strongest large‐scale storm‐time enhancements were detected over the Asian and Pacific regions during the main and early recovery phases of the storm. In the American sector, there occurred the most complex effects caused by the action of multiple drivers. At the beginning of the storm, a large positive disturbance occurred over North America at low and high latitudes, driven by the storm‐time reinforcement of the equatorial ionization anomaly (at low latitudes) and by particle precipitation (at high latitudes). During local nighttime hours, we observed numerous medium‐scale positive and negative ionospheric disturbances at middle and high latitudes that were attributed to a storm‐enhanced density (SED)‐plume, mid‐latitude ionospheric trough, and particle precipitation in the auroral zone. In South America, total electron content (TEC) maps clearly showed the presence of the equatorial plasma bubbles, that, however, were not seen in data of Rate‐of‐TEC‐change index (ROTI). Global ROTI maps revealed intensive small‐scale irregularities at high latitudes in both hemispheres within the auroral region. In general, the ROTI disturbance “imaged” quite well the auroral oval boundaries. The most intensive ionospheric fluctuations were observed at low and mid‐latitudes over the Pacific Ocean. The storm also affected the positioning accuracy by GPS receivers: during the main phase of the storm, the precise point positioning error exceeded 0.5 m, which is more than five times greater as compared to quiet days.
A Statistical Investigation of Inertia Gravity Wave Activity Based on MST Radar Observations at Xianghe (116.9°E, 39.8°N), China
Authors: Ning Wu Han , Huang Kai Ming , Zhang Shao Dong , Huang Chun Ming , Gong Yun , Ma Zheng 
Published: December 2021

AbstractUsing three‐dimensional wind observations from a Mesosphere‐Stratosphere‐Troposphere radar at Xianghe for two years from September 2011 to August 2013, we study inertia gravity wave (IGW) activity in the two height segments of 3–10 and 15–25 km to reveal the characteristics of waves in the source region at midlatitude. Case investigation indicates that three‐dimensional wind fluctuations are usually dominated by a strong IGW. Statistics on 15,617 IGWs extracted show that most waves have typical horizontal scales of tens to thousands of kilometers, the vertical scale of a few kilometers, intrinsic frequencies in 1–4 times the inertial frequency, and amplitudes of 1–4 ms−1 in horizontal winds but less than 0.3 ms−1 in the vertical wind. In the lower region, occurrence possibilities of upward and downward propagating waves are almost the same throughout the year. Whereas in the upper region, IGWs display a predominant upward propagation with a maximum of 85.3% in February but a minimum of 63.6% in July, and a preferential propagation in the zonal direction relative to the meridional direction. Meanwhile, wave energy has a prominent seasonal cycle with the maximum in winter and the minimum in summer. Subtropical jet, as wave source and propagation condition, plays an important role in these different features between the two regions. The annual average of momentum flux indicates that the IGWs in the lower stratosphere can apply a persistent eastward drag on the background flow at higher altitudes through momentum transported by these waves.
Investigating the Understanding of Oxidation Chemistry Using 20 Years of Airborne OH and HO2 Observations
Authors: Miller David O. , Brune William H. 
Published: December 2021

AbstractHydroxyl (OH) and hydroperoxyl (HO2) strongly influence the atmosphere's oxidation of gases emitted from Earth's surface and the formation and aging of aerosol particles. Thus, understanding OH and HO2 chemistry is essential for examining the impact of human activity on future atmospheric composition and climate. Using the OH and HO2 data set collected with the Penn State Airborne Tropospheric Hydrogen Oxides Sensor (ATHOS) during nine aircraft missions over the past 20 years, we compare observed OH and HO2 to that modeled using the same near‐explicit photochemical box model. In general, the agreement is well within the combined uncertainties of the observations and models, even when the model is constrained only with a common data set of simultaneous measurements. However, in environments such as cities, forests, and pollution plumes, the model chemical mechanism and size of the data set of constraining measurements do matter. The model constrained by the full set of measurements better simulates OH loss and OH in these regions than the model constrained by the common set of measurements. In cleaner regions, the differences between observed and modeled OH and HO2 found in previous studies generally remain and do not appear to be systematic, indicating that the differences are driven by measurement issues for ATHOS and/or other instruments. Thus, these comparisons indicate that the oxidation chemistry in most of the free troposphere is understood to as well as current measurements can determine. The focus of future research needs to be on regions rich in volatile organic compounds, where observed‐to‐modeled differences are more persistent, and on improving measurement consistency.