Statistical approach to determine the salinized ground water flow path and hydrogeochemical features around the underground LPG cavern,Korea     

Jeongho Lee  Ji‐Hoon Kim  Hun‐Mi Kim  Ho‐Wan Chang 《水文研究》2007,21(26):3615-3626

The ground water flow path of the coastal area in the Yellow Sea, Korea, was interpreted using both the cross‐correlation analysis of hydraulic properties and the principal component analysis (PCA) of ground water chemistry. Data was obtained from observation wells in the underground liquefied petroleum gas (LPG) cavern constructed in the coastal area of Pyeongtaek. Cross‐correlation results showed that the operating pressure became more influenced on artificial factors for the variation of the groundwater level of the study area (45–66% of correlation coefficient) even though its affecting area was limited to the region with fractures or faults, and also showed that the delay time from the variation of operating pressure to the fluctuation of ground water level were relatively long periods (28–31 days). Three hydrogeochemical events (encrusted cement dissolution, host rock dissolution, and seawater intrusion), which were dominantly influenced on ground water quality, could be induced from the result of PCA. Quantitative evaluation for these events using the mixed equation with principal component scores suggest that the dissolution of encrusted cement materials was the predominant factor (39·0% of the total mixed proportion) to change the chemical composition of the seepage water during the ground water flow from the observation wells to the cavern. Integration of the statistical results also imply that ground water flow and hydrogeochemistry were predominantly affected by artificial factors such as cavern operation pressure and dissolution of encrusted cement materials, which were interdependent factors on the observation wells with high cross‐correlation coefficients and pH. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Statistical control chart for regime identification in volcanic time series     

Chih-Hsiang Ho 《Mathematical Geology》1992,24(7):775-787

In an important paper, Mulargia et al. (1987) address the importance of quantitative and objective identification of different regimes of a volcano. They develop a procedure based on the two-sample Kolmogorov-Smirnov (K-S) statistic. The K-S test is a general-purpose test that discriminates between two data sets as belonging to two different regimes based on their empirical distribution functions. The empirical distribution function is designed to describe the aggregate behavior of the volcanic activity, and it is constructed from the orders of the length of the collected repose times in each data set. In this article, we use the idea of statistical process control to distinguish between the variation inherent in the observed repose times and the extraordinary variation that signals a real change in the regimes. We construct a table of control limits, and we demonstrate the procedure of regime identification based on a simple control chart. It shows a point outside the control limits almost as soon as the process enters a new regime. The basis of the statistical process control mechanism is a simple Poisson process, which is state of the art. The proposed control charting procedure is an eruption by eruption procedure, which follows the original chronological order of the eruptions. This procedure is applied to the eruptive history of the Mount Etna volcano. The application shows schematically that the procedure presents a visual interpretation of the identified regimes and can be practically translated for tabular or manual use.  相似文献   

Composition and temperatures of the topside ionosphere over Arecibo     

M.C. Ho  D.R. Moorcroft 《Planetary and Space Science》1975,23(2):315-322

Results of analysis of about 150 autocorrelation functions are presented for the period from about 2300 hr on 5 October to about 1200 hr on 7 October 1967. A large percentage concentration of helium ions are observed. It reaches a value as high as 50 per cent with a maximum at around 800 km. Downward heat fluxes deduced from the temperature variations yield a value of about 2–2.5 × 10⁹ eV cm^?2 sec^?1 during the period 1200–1600 hr and a value of about 1.5 × 10⁸ eV cm^?2 sec^?1 during the period 0100–0400 hr at night. These agree well with other measurements. The O⁺ ions are found not to be in diffusive equilibrium, and from the O⁺ fluxes and the electron density profiles, the O⁺ drift velocity has been estimated. It is found that the speed can be as high as 1–5 × 10³ cm sec^?1 even at altitudes as high as 700 km.  相似文献   

Venus I. Carbon monoxide distribution and molecular-line searches     

W.J. Wilson  M.J. Klein  R.K. Kahar  S. Gulkis  E.T. Olsen  P.T.P. Ho 《Icarus》1981,45(3):624-637

An observational program to study variations of the vertical distribution of CO in the Venus atmosphere is presented. Measurements of the J = 0 → 1 absorption line at 2.6 mm wavelength are reported for two phase angles in 1977, one near eastern elongation (Feb.) and the other near inferior conjunction (Apr.). The two spectra are significantly different, with the April absorption line being narrower and deeper. The results of numerical inversion calculations show that the CO mixing ratio increases a factor of ～ 100 between 78 and 100 km and that the CO abundance above ～ 100 km is greatest on the night-side hemisphere. These conclusions are in qualitative agreement with theoretical models. In addition to the CO observations, a search for other molecules was made to provide further information on the composition of the Venus middle atmosphere. The J = 0 → 1 transition of ¹³CO was detected and upper limits were derived for nine other molecules.  相似文献   

Assessment of the changes in extreme vulnerability over East Asia due to global warming   总被引：1，自引：0，他引：1  

Min-Hee Lee  Chang-Hoi Ho  Jinwon Kim  Chang-Keun Song 《Climatic change》2012,113(2):301-321

A number of indices have been employed to describe weather extremes on the basis of climate regimes and public concerns. In this study, we combined these traditional indices into four groups according to whether they relate to warm (T_warm), cold (T_cold), wet (P_wet), or dry (P_dry) extremes. Analysis of the combined indices calculated for the daily temperatures and precipitation at 750 meteorological stations in Korea, China, and Japan for 1960s?C2000s shows increasing trends in T_warm and P_dry events and decreasing trends in T_cold events in recent decades, particularly in the northern part of East Asia. A notable regional variation is an increase in the P_wet events in the Korean Peninsula. We applied the same analysis to a 200-year global climate model simulation for 1900?C2099 using the National Center for Atmospheric Research-Community Climate System Model 3. During the 20th century, the changes in T_warm and T_cold calculated from the model data are largely consistent with those calculated from the observations, especially in northern East Asia. The model projections for the 21st century indicate statistically significant increasing T_warm and decreasing T_cold trends in extreme events over the region. Results obtained from historical archives and model simulations using our combined weather extreme indices suggest that northern East Asia will be subject to increased warm and dry extremes and the Korea Peninsula will experience more wet extremes.  相似文献   

On the peculiar momentum of baryons after reionization     

Carlos Hernández-Monteagudo  Shirley Ho 《Monthly notices of the Royal Astronomical Society》2009,398(2):790-806

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Galaxy activity in merging binary galaxy clusters     

Ho Seong Hwang †  Myung Gyoon Lee 《Monthly notices of the Royal Astronomical Society》2009,397(4):2111-2122

We present the results of a study of galaxy activity in two merging binary clusters (A168 and A1750) using the Sloan Digital Sky Survey (SDSS) data supplemented with the data in the literature. We have investigated the merger histories of A168 and A1750 by combining the results from a two-body dynamical model and X-ray data. In A168, two subclusters appear to have passed each other and to be coming together from the recent maximum separation. In A1750, two major subclusters appear to have started interaction and to be coming together for the first time. We find an enhanced concentration of the galaxies showing star formation (SF) or active galactic nuclei (AGN) activity in the region between two subclusters in A168, which were possibly triggered by the cluster merger. In A1750, we do not find any galaxies with SF/AGN activity in the region between two subclusters, indicating that two major subclusters are in the early stage of merging.  相似文献   

Geochemistry and sediment in the main stream of the Ca River basin,Vietnam: weathering process,solute-discharge relationships,and reservoir impact     

Phuong  Ho Thi  Okubo  Kenji  Azhar Uddin  Md. 《中国地球化学学报》2019,38(5):627-641

Acta Geochimica - In this study, we investigated the chemical composition of dissolved solids in the Ca River basin, North-Central Vietnam. Water samples were collected from August 2017 to July...  相似文献   

Interdecadal change in typhoon genesis condition over the western North Pacific     

Yumi Choi  Kyung-Ja Ha  Chang-Hoi Ho  Chul Eddy Chung 《Climate Dynamics》2015,45(11-12):3243-3255

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Assessing Cryptic Invasion State: Fine-Scale Genetic Analysis of Ciona savignyi Population in Putative Native Habitat of the Korean Coast     

Yi  Chang Ho  Kim  Won 《Ocean Science Journal》2020,55(1):99-113

The solitary ascidian, Ciona savignyi (Ascidiacea, Enterogona) is a notorious marine invader still expanding its habitat range worldwide. This species is considered native to the North West Pacific, but its indigeneity in Korean coastal waters has been questioned because of outdated taxonomic records and its inhabitation of oceanographically marginal areas. To clarify their cryptic invasion state, 247 individual C. savignyi samples were collected from 12 harbors and marinas on the Korean coast, and a 744 bp region of mitochondrial DNA (mtDNA) cytochrome c oxidase subunit I gene was sequenced and analyzed. Our analyses of population genetic structure and demographic history provided considerable pieces of evidence supporting their long-term establishment on the Korean coasts: differentiated population genetic structure, sequentially arrayed star-shape haplotype network, neutrality test results of past population expansions, and post-glacial colonization pattern of demography. Consequently, we concluded that C. savignyi populations on the Korean Coast are indigenous rather than exotic. These results could be used as reference data for further phylogeo graphic and demographic studies of problematic Ciona species, and to clarify and resolve similar cryptic invasion states of the other Korean coastal marine organisms. This study is the first to resolve the cryptic in vasion state of Korean marine organisms using genetic analysis.

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