bluuebunny/crossref_metadata_2025_split huggingface dataset:
An attempt to infer information on planetary wave by analyzing sporadic E layers observations
Authors: Zuo Xiaomin , Wan Weixing , Zhao Guangxin 
Published: August 2014

Abstract
In this paper we presented two typical global 6-day planetary wave oscillations occurring in sporadic E layers. By analyzing the f
o
E
s time series observed from several ionosonde stations on the basis of the methods suggested by Haldoupis and Pancheva (2002), we computed estimates for the PW propagation direction, zonal wave number and phase velocity. We obtained results that the 6-day PW, with zonal wave number about 1, propagates westward, which are in agreement with those reported from radar and satellite neutral wind MLT measurements. The results provide experimental evidence for a close relationship between PWs and midlatitude E
s. In addition, the study proves the validity of E
s observations measured routinely and rather reliably with a dense global network of digital ionosondes used as an alternative means of studying large-scale neutral atmospheric dynamics in the MLT region.
Crustal thickness beneath the Ryukyu arc from travel-time inversion
Authors: Nakamura Mamoru , Umedu Nozomi 
Published: August 2014

Abstract
First P-wave arrival times recorded by the seismic network in the Ryukyu arc were analyzed in order to image the lateral variation in crustal thickness beneath the Ryukyu arc. The results indicate a low P
n velocity (7.5 km/s) in the Ryukyu arc and a relatively high P
n velocity (7.9 km/s) in the Okinawa Trough. The crustal thickness changes between the northern-and-central Ryukyu arc (range 23–27 km) and the southern Ryukyu arc (range 29–44 km). The crustal thickness of the former is consistent with that in the northern-and-central Okinawa Trough, suggesting a flat Moho stretching from the Okinawa Trough to the Ryukyu arc. This flat Moho extends uniformly over a wide area. In contrast, the crustal thickness in the southern Ryukyu arc is consistent with the characteristics of the crustal structure whereby the Moho becomes shallower in the vicinity of the axis of the Okinawa Trough and deepens remarkably with increasing distance from the axis in the southern Ryukyu arc. These differences would be caused by the difference in rifting style between the northern-and-central Okinawa Trough and the southern Okinawa Trough.
Earthquake hazard assessment in seismogenic systems through Markovian artificial neural network estimation: an application to the Japan area
Authors: Herrera C. , Nava F. A. 
Published: August 2014

abstractAn earlier work (Herreraet al.:Earth Planets Space,58, 973–979, 2006) introduced two new methods for seismic hazard evaluation in a geographic area with distinct, but related, seismogenic regions. These two methods are based on modeling the transition probabilities ofstates, i.e. patterns of presence or absence of large earthquakes, in the regions, as a Markov chain. This modeling is, in turn, based on a straightforward counting of observed transitions between states. Thedirectmethod obtains transition probabilities among states that include events with magnitudesM≥Mr, whereMris a specified threshold magnitude. Themixedmethod evaluates probabilities for transitions from a state withM≥Mrmto a state withM≥MrM, whereMrm<MrM. Both methods gave very good results when applied to the Japan area, with the mixed method giving the best results and an improved magnitude range. In the work presented here, we propose other methods that use the learning capacity of an elementary neuronal network (perceptron) to characterize the Markovian behavior of the system; these neuronal methods,directandmixed, gave results ∼7 and ∼6% better than the counting methods, respectively. Method performance is measured using grading functions that evaluate a tradeoff between positive and negative aspects of performance. This procedure results in a normalized grade being assigned that allows comparisons among different models and methods.
The Upper Atmosphere and Plasma Imager/the Telescope of Visible Light (UPI/TVIS) onboard the Kaguya spacecraft
Authors: Taguchi M. , Sakanoi T. , Okano S. , Kagitani M. , Kikuchi M. , Ejiri M. , Yoshikawa I. , Yamazaki A. , Murakami G. , Yoshioka K. , Kameda S. , Miyake W. , Nakamura M. , Shiokawa K. 
Published: August 2014

Abstract
The Upper Atmosphere and Plasma Imager (UPI) was placed in a lunar orbit in order to study both the Moon and Earth. The UPI consists of two telescopes: a Telescope of Extreme Ultraviolet (TEX) and a Telescope of Visible Light (TVIS), which are both mounted on a two-axis gimbals system. The TVIS is equipped with fast catadioptric optics and a high-sensitivity CCD to image swift aurora and dark airglow in the terrestrial upper atmosphere. TVIS has a field-of-view equivalent to the Earth’s disk as seen from the Moon. The spatial resolution is about 30 km × 70 km on the Earth’s surface at auroral latitudes. The observation wavelengths can be changed by selecting different bandpass filters. Using the images of the northern and southern auroral ovals taken by TVIS, the intensities and shapes of the conjugate auroras will be quantitatively compared. Using the airglow imaging, medium- and large-scale ionospheric disturbances will be studied. In this paper, the instrumental design and performance of TVIS are presented.
Nonlinear thermoremanence corrections for Thellier paleointensity experiments on single plagioclase crystals with exsolved magnetites: a case study for the Cretaceous Normal Superchron
Authors: Usui Yoichi , Nakamura Norihiro 
Published: August 2014

Abstract
Single plagioclase paleointensity experiment has been an excellent tool to reliably estimate ancient geomagnetic field intensity. Although transparent plagioclases with magmatic nanophase magnetites have shown their potential for paleointensity estimation, in most cloudy plagioclases with exsolved magnetites, the problems of strong anisotropy as rod-shape magnetites, the hyperbolic tangential saturation of thermoremanence (TRM), and slow cooling of host plutons need to be addressed. In this paper, we propose experimental schemes to address these problems with considerations of error estimation and uncertainty for paleointensity experiments on exsolved magnetite. First, in order to experimentally check the effect of the hyperbolic tangential saturation of TRM, we performed Thellier simulation experiments using laboratory total TRM as simulated natural remanence (NRM). Single cloudy plagioclases were sampled from early Cretaceous granite in the Kitakami massif, Northeast Japan. We designed the experiment where the total TRM and the partial TRMs in the Thellier experiments were acquired under different field intensities. For these experiments, correction for hyperbolic tangential TRM acquisition yielded precise field intensity estimations. Next, Thellier experiments on NRM of the crystals from the same granite were performed as a demonstration of correction schemes for both magnetic anisotropy and hyperbolic tangential TRM acquisition. Precise determination of anisotropy tensor seems to be the major challenge for single plagioclase paleointensity estimation with exsolved magnetite.
The seasonal and solar cycle variations of electron density gradient scale length, vertical drift and layer height during magnetically quiet days: Implications for Spread F over Trivandrum, India
Authors: Manju G. , Devasia C. V. , Ravindran Sudha 
Published: August 2014

Abstract
A study has been carried out on the behaviour of electron density gradient scale length, L, vertical drift and layer height, around post sunset hours, during the magnetically quiet days of summer, winter and equinox seasons of solar maximum (2002) and minimum years (1995), using ionosonde data of Trivandrum (8.5°N, 76.5°E, dip = 0.5°N) in the Indian longitude sector. The results indicate a clear seasonal and solar cycle variation in all the three parameters. Further, the seasonal variation of equatorial Spread F (ESF) during the above period is examined in terms of the relative roles of L, the vertical drift and layer height (of the F layer) in the triggering of the collisional Rayleigh-Taylor instability. The results, show for the first time, that L also plays an important role, in controlling the quiet time seasonal and solar cycle variability of ESF; whereas in earlier studies this parameter had been taken to be constant. The detailed results are presented and discussed.
A numerical study on amplitude characteristics of the terdiurnal tide excited by nonlinear interaction between the diurnal and semidiurnal tides
Authors: Huang Chun Ming , Zhang Shao Dong , Yi Fan 
Published: August 2014

Abstract
A fully nonlinear numerical tidal model has been developed with the aim of presenting amplitude features of the terdiurnal tide excited by nonlinear interaction between the diurnal and semidiurnal tides. Since the superposition of the migrating diurnal and semidiurnal tidal solutions from the GSWM-00 (Global Scale Wave Model 2000) is taken as the initial disturbance for this nonlinear model, the diurnal and semidiurnal tides are allowed to nonlinearly interact with each other. The analyses on the simulations show that the migrating terdiurnal tide can be significantly excited by the nonlinear interaction between the diurnal and semidiurnal tides in the mesosphere and lower thermosphere (MLT) region, especially above 90 km, and have pronounced amplitudes (wind speeds over 15 m s−1 and temperature over 10 K) in the lower thermosphere (90–110 km). In addition, its amplitudes vary strongly with season and maximize during equinoctial months at low and middle latitudes, and its zonal wind component is larger than the meridional wind component. Simultaneously, the diurnal and semidiurnal tides exhibit evident variations, indicating that the wave-wave and wave-mean flow interactions are the important cause of the tidal variability. Our calculations also illustrate the remarkable alteration of the background fields induced by the mean flow/tidal interaction, implying this interaction should be comprehensively considered in describing global atmospheric dynamic and thermal structures in the MLT region.
Procrustean solution of the 9-parameter transformation problem
Authors: Awange J. L. , Bae K. -H. , Claessens S. J. 
Published: August 2014

Abstract
The Procrustean “matching bed” is employed here to provide direct solution to the 9-parameter transformation problem inherent in geodesy, navigation, computer vision and medicine. By computing the centre of mass coordinates of two given systems; scale, translation and rotation parameters are optimised using the Frobenius norm. To demonstrate the Procrustean approach, three simulated and one real geodetic network are tested. In the first case, a minimum three point network is simulated. The second and third cases consider the over-determined eight- and 1 million-point networks, respectively. The 1 million point simulated network mimics the case of an air-borne laser scanner, which does not require an isotropic scale since scale varies in the X, Y, Z directions. A real network is then finally considered by computing both the 7 and 9 transformation parameters, which transform the Australian Geodetic Datum (AGD 84) to Geocentric Datum Australia (GDA 94). The results indicate the effectiveness of the Procrustean method in solving the 9-parameter transformation problem; with case 1 giving the square root of the trace of the error matrix and the mean square root of the trace of the error matrix as 0.039 m and 0.013 m, respectively. Case 2 gives 1.13×10−12 m and 2.31×10−13 m, while case 3 gives 2.00×10−4 m and 1.20 × 10−5 m, which is acceptable from a laser scanning point of view since the acceptable error limit is below 1 m. For the real network, the values 6.789 m and 0.432 m were obtained for the 9-parameter transformation problem and 6.867 m and 0.438 m for the 7-parameter transformation problem, a marginal improvement by 1.14%.
Integrating potential fields with remote sensing data for geological investigations in the Eljufra area of Libya
Authors: Saadi Nureddin Mohamed , Watanabe Koichiro , Imai Akira , Saibi Hakim 
Published: August 2014

Abstract
In this study, we successfully integrated geological data, potential field data, and remote sensing data with the aim of investigating and improving our knowledge of the structural setting of the Eljufra area, northwestern Libya. SPOT-5 panchromatic band and digital elevation models (DEM) were used to construct surface shaded maps, and gravity and aeromagnetic surveys were used to provide information on subsurface structures and the nature of intrusive bodies. The results revealed that the prevailing trend of lineaments is NNW-SSE and NNE-SSW. A Bouguer anomaly map revealed that horst and graben blocks occur inside the large graben. An analytic signal method was applied to the aeromagnetic data to estimate locations and the minimum depths to the contact. A comparison of gravity and magnetic data provided information on hydrothermally altered basalt and sediment density. An anticlinal structure was detected in the western part of the study area. The effects of faults on basalt rocks indicated geological time for volcanic activity.
Quantitative description of oscillatory zoning in basaltic to dacitic plagioclases from the Shirahama Group, Japan
Authors: Tsune Akira , Toramaru Atsushi 
Published: August 2014

Abstract
New criteria related to the origin of oscillatory zoning (OZ) in plagioclase are presented. We compare the OZs in basaltic to those of dacitic plagioclases in the tholeiitic series volcanic rocks of the Shirahama Group, Izu Peninsula, Japan. Nomarski differential interference contrast (NDIC) images of the etched thin sections are used to measure zone thicknesses of the OZs. The normalized standard deviations per data series of the thicknesses are then calculated. We found that the average thicknesses are almost constant (mostly from 2 to 3 μm) through all the rock samples. This constancy corresponds to our idea that the length of oscillation, D/V (D: diffusivity in the melt; V: growth velocity of plagioclase) is almost constant for a variety of melt viscosity because strong dependences on the viscosity of D and V are canceled out in D/V. Consequently, we concluded that the growth of the OZ is basically controlled by an interface kinetics mechanism. In contrast, the plagioclases in SiO2-rich rocks have the following features: (1) larger standard deviations, (2) abundant erode-like zones, and (3) large oscillation amplitudes. These features reveal that the OZ patterns of plagioclases in more silicic magmas are disturbed due to change of the environmental parameters under the magma dynamics.
Precise remote-monitoring technique of water volume and temperature of a crater lake in Aso volcano, Japan: implications for a sensitive window of a volcanic hydrothermal system
Authors: Terada Akihiko , Hashimoto Takeshi , Kagiyama Tsuneomi , Sasaki Hisashi 
Published: August 2014

Abstract
A high-resolution Digital Surface Model and a commercial digital camera have enabled precise and continuous monitoring of the crater lake at Aso volcano. From July 2006 onwards, infrared (IR) thermometry has been used with this system, enabling more accurate measurements of lake volume and temperature based on simple and intensive observations than has been possible in any other previous studies. The heat discharge remained largely constant at approximately 220 MW, with the exception of an abrupt increase to 280 MW that coincided with a rapid decrease in the water level in August 2007. Simultaneously, an increase in temperature at a shallow depth was suggested by other observations. The crater lake was found to respond to even slight changes in volcanic fluid supply, which can be well quantified by our method. Thus, a crater lake can be monitored more precisely than subaerial fumaroles whose energy estimation is often accompanied by large uncertainties. Our monitoring technique of a crater lake provides information on the subsurface hydrothermal system beneath it, for which any in-situ measurements are practically impossible.
Digital beacon receiver for ionospheric TEC measurement developed with GNU Radio
Authors: Yamamoto Mamoru 
Published: August 2014

Abstract
A simple digital receiver named “GNU Radio Beacon Receiver (GRBR)” was developed for the satelliteground beacon experiment to measure the ionospheric total electron content (TEC). The open-source software toolkit for the software defined radio, GNU Radio, is utilized to realize the basic function of the receiver and perform fast signal processing. The software is written in Python for a LINUX PC. The open-source hardware called Universal Software Radio Peripheral (USRP), which best matches the GNU Radio, is used as a frontend to acquire the satellite beacon signals of 150 and 400 MHz. The first experiment was successful as results from GRBR showed very good agreement to those from the co-located analog beacon receiver. Detailed design information and software codes are open at the URL http://www.rish.kyoto-u.ac.jp/digitalbeacon/
Holocene ages and inland source of wood blocks that emerged onto the seafloor during the 2007 Chuetsu-oki, central Japan, earthquake
Authors: Kaneda Heitaro , Nakata Makoto , Hosoo Yoshihiro , Sugiyama Yuichi , Okamura Yukinobu 
Published: August 2014

Abstract
At least 300 tons of subrounded to well-rounded wood blocks emerged onto the seafloor at a water depth of 70–100 m during the 2007 M
w 6.6 Chuetsu-oki, central Japan, earthquake. Radiocarbon dating and taxonomic identification of eight of those wood blocks suggest that they were transported from inland during the middle to late Holocene, buried by subsequent sedimentation, and brought up onto the seafloor in 2007, most likely by submarine liquefaction induced by strong shaking. In particular, all eight blocks gave ages older than 2500 cal yr BP, implying the possibility that the 2007 earthquake was the first earthquake during the last two millennia to have caused shaking strong enough to induce submarine liquefaction in the 2007 meizoseismal area. However, we cannot rule out the possibility of multiple large earthquakes after approximately 2 ka, if the buried wood sources cannot be emptied by a single earthquake. Further studies are required to examine paleoseismic implications of the emergence of these wood blocks in 2007.
VHF radar observations of nighttime F-region field-aligned irregularities over Kototabang, Indonesia
Authors: Otsuka Y. , Ogawa T. , Effendy  
Published: August 2014

Abstract
We report, for the first time, continuous observations of the nighttime F-region field-aligned irregularities (FAIs) over Indonesia. A VHF radar with operating frequency of 30.8 MHz and peak power of 20 kW has been operated at Kototabang (0.20°S, 100.32°E; dip latitude 10.4°S), Indonesia since February 2006. Five beams were allocated between ±54° in azimuth around geographic south (126°–234°). From the continuous observation from February 2006 to November 2007, we found that FAIs appeared frequently at pre-midnight between March and May and at post-midnight between May and August. The pre-midnight FAIs coincided well with GPS scintillation observed at the same site. Seasonal and local time variations of the pre-midnight FAI occurrence are consistent with those of equatorial plasma bubbles reported in previous studies (e.g., Maruyama and Matuura, 1984). These results indicate that the pre-midnight FAIs could be associated with the equatorial plasma bubbles. On the other hand, seasonal and local time variations of the post-midnight FAIs were inconsistent with those of the plasma bubbles. The features of the post-midnight FAIs can be summarized as follows: (1) The post-midnight FAIs are not accompanied by GPS scintillations. (2) Most of the post-midnight FAI regions do not show propagation, but some of them propagate westward. (3) Echo intensity of the post-midnight FAIs was weaker than that of the pre-midnight FAIs. These features are similar to those of the FAI echoes that have been observed at mid-latitude (e.g., Fukao et al., 1991). At Kototabang, Fukao et al. (2004) have firstly observed FAIs that resemble those at mid-latitude. The present paper reports statistical characteristics of the mid-latitude-type FAIs observed at Kototabang.
Kelvin waves in stratosphere, mesosphere and lower thermosphere temperatures as observed by TIMED/SABER during 2002–2006
Authors: Forbes Jeffrey M. , Zhang Xiaoli , Palo Scott E. , Russell James , Mertens Christopher J. , Mlynczak Martin 
Published: August 2014

Abstract
Temperature measurements from the SABER instrument on the TIMED spacecraft are used to elucidate the properties of Kelvin waves and other equatorial oscillations over the altitude range 20–120 km during 2002–2006. The dominant Kelvin waves transition from long periods (52–10 days) and short wavelengths (9–13 km) in the stratosphere, to shorter periods (2–3 days) and longer wavelengths (35–45 km) in the 80–120 km height region. Ultra-Fast Kelvin Waves (UFKW) with periods of 2.5–4.5 days intermittently exist at amplitudes of order 3–10 K between 80–120 km during all months of the year, with variability at periods typically in the 20–60 day range. An Intra-seasonal oscillation (ISO) of zonal mean temperatures also exists with periods 20–60 days that may be driven by Eliassen-Palm Flux Divergences (EPFD) due, at least in part, to UFKW and migrating diurnal tides.
Diurnal and intraseasonal variation of UTLS vertical wind disturbance in the equatorial region and its relation to tropospheric convective activities
Authors: Kozu Toshiaki , Kodama Yasu-Masa , Shibagaki Yoshiaki , Shimomai Toyoshi , Kawashima Masayuki , Alexander Simon P. 
Published: August 2014

Abstract
Vertical wind variations in the Upper Troposphere and Lower Stratosphere (UTLS) measured by the Equatorial Atmosphere Radar (EAR) at Kototabang, Sumatra, between 2003 and 2005 but mainly in 2004, have been statistically analyzed to study the characteristics of wind variances associated with convective activity, which is related to gravity wave generation and propagation. The analyses are intended to characterize relatively short period disturbances of less than 12 hours and an energy propagation direction of a relatively high elevation angle, and to relate vertical wind variations to convective activity close to the EAR. Correlation analyses between vertical wind variations and rainfall show that the wind variances have a clear diurnal variation indicating probable effects of tropospheric convection. They also show some intraseasonal variation. However, there are no significant correlations with the Out-going Long-wave Radiation (OLR) anomaly. The correlations between variances at UT and LS suggest that the UTLS coupling of vertical wind variation through upward propagation of gravity wave is similarly evident in the afternoon during both the active and the inactive phase of OLR that is a proxy of large-scale convective activity.
Soft computing methods for geoidal height transformation
Authors: Akyilmaz O. , Özlüdemir M. T. , Ayan T. , Çelik R. N. 
Published: August 2014

AbstractSoft computing techniques, such as fuzzy logic and artificial neural network (ANN) approaches, have enabled researchers to create precise models for use in many scientific and engineering applications. Applications that can be employed in geodetic studies include the estimation of earth rotation parameters and the determination of mean sea level changes. Another important field of geodesy in which these computing techniques can be applied is geoidal height transformation. We report here our use of a conventional polynomial model, the Adaptive Network-based Fuzzy (or in some publications, Adaptive Neuro-Fuzzy) Inference System (ANFIS), an ANN and a modified ANN approach to approximate geoid heights. These approximation models have been tested on a number of test points. The results obtained through the transformation processes from ellipsoidal heights into local levelling heights have also been compared.