Rainfall network design using kriging and entropy   总被引：4，自引：0，他引：4  

Yen‐Chang Chen  Chiang Wei  Hui‐Chung Yeh 《水文研究》2008,22(3):340-346

The spatial distribution of rainfall is related to meteorological and topographical factors. An understanding of the weather and topography is required to select the locations of the rain gauge stations in the catchment to obtain the optimum information. In theory, a well‐designed rainfall network can accurately represent and provide the needed information of rainfall in the catchment. However, the available rainfall data are rarely adequate in the mountainous area of Taiwan. In order to provide enough rainfall data to assure the success of water projects, the rainfall network based on the existing rain gauge stations has to be redesigned. A method composed of kriging and entropy that can determine the optimum number and spatial distribution of rain gauge stations in catchments is proposed. Kriging as an interpolator, which performs linear averaging to reconstruct the rainfall over the catchment on the basis of the observed rainfall, is used to compute the spatial variations of rainfall. Thus, the rainfall data at the locations of the candidate rain gauge stations can be reconstructed. The information entropy reveals the rainfall information of the each rain gauge station in the catchment. By calculating the joint entropy and the transmitted information, the candidate rain gauge stations are prioritized. In addition, the saturation of rainfall information can be used to add or remove the rain gauge stations. Thus, the optimum spatial distribution and the minimum number of rain gauge stations in the network can be determined. The catchment of the Shimen Reservoir in Taiwan is used to illustrate the method. The result shows that only seven rain gauge stations are needed to provide the necessary information. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

An integrated model for predicting rainfall-induced landslides   总被引：2，自引：0，他引：2  

Kang-Tsung Chang  Shou-Hao Chiang 《Geomorphology》2009,105(3-4):366-373

This study proposes a novel method that combines a deterministic slope stability model and a statistical model for predicting rainfall-induced landslides. The method first uses the deterministic model to derive the rainfall rate critical to induce slope failure for each land unit. Then it calculates the difference between the critical rainfall threshold and estimated rainfall intensity. Using the difference and estimated rainfall duration as explanatory variables, the method derives a logit (integrated) model to compute landslide occurrence probabilities. To demonstrate the effectiveness of this method, the study used radar rainfall estimates and landslides associated with a typhoon (tropical cyclone) to develop the integrated model and the same types of data associated with another typhoon to validate the model. The model had a modified success rate of 84.0% for predicting landslides and stable areas, and model validation yielded a modified success rate of 87.4%. Both rates were better than those from the critical rainfall model. The main advantage of the integrated model lies in its use of rainfall variables that are not included in calculating the critical rainfall. Also, as a probabilistic model, the integrated model is better suited for decision-making in watershed management. This study has advanced the method for predicting rainfall-triggered landslides.  相似文献   

Field Determination of Geological/Chemical Properties of an Aquifer by Cone Penetrometry and Headspace Analysis     

C. Y. Chiang  K. R. Loos  R. A. Klopp 《Ground water》1992,30(3):428-436

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Mapping urban growth of the capital city of Honduras from Landsat data using the impervious surface fraction algorithm     

Nguyen-Thanh Son  Chi-Farn Chen  Cheng-Ru Chen  Shou-Hao Chiang 《国际地球制图》2016,31(3):328-341

This study developed an impervious surface fraction algorithm (ISFA) for automatic mapping of urban areas from Landsat data. We processed the data for 2001 and 2014 to trace the urbanization of Tegucigalpa, the capital city of Honduras, using a four-step procedure: (1) data pre-processing to perform image reflectance normalization, (2) quantification of impervious surface area (ISA) using ISFA, (3) accuracy assessment of mapping results and (4) change analysis of urban growth. The mapping results compared with the ground reference data confirmed the validity of ISFA for automatic delineation of ISA in the study region. The overall accuracy and Kappa coefficient achieved for 2001 were 92.8% and 0.86, while the values for 2014 were 91.8% and 0.84, respectively. The results of change detection between the classification maps indicated that ISA increased approximately 1956.7 ha from 2001 to 2014, mainly attributing to the increase of the city’s population.  相似文献   

Editorial     

Chiang C. Mei 《Applied Ocean Research》1979,1(1):2

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An array of Hagen-Cockerell wave power absorbers in head seas     

Pierre Haren  Chiang C. Mei 《Applied Ocean Research》1982,4(1):51-56

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Wave power extraction by a train of rafts: hydrodynamic theory and optimum design     

Pierre Haren  Chiang C. Mei 《Applied Ocean Research》1979,1(3):147-157

A theory is given for a two-dimensional wave power device which consists of a train of floating rafts whose wave-induced rotation about the hinges is used to generate energy. Ideal efficiency, wave forces and raft movements are studied by a linearized shallow water theory which is sufficiently simple to enable an investigation for optimum designs under a variety of criteria of efficiency and cost-effectiveness. For a sample raft train, a numerical theory for arbitrary wavelength is also applied, yielding results which are not essentially different from those by the long wave approximation.  相似文献   

Tropical Pacific response to continental ice sheet topography     

Shih-Yu Lee  John C. H. Chiang  Ping Chang 《Climate Dynamics》2015,44(9-10):2429-2446

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Radon distribution in groundwater of Taiwan     

Y. L. Han  M. C. Tom Kuo  K. C. Fan  C. J. Chiang  Y. P. Lee 《Hydrogeology Journal》2006,14(1-2):173-179

Radon levels were surveyed in 517 monitoring wells constructed in five major groundwater areas of Taiwan. The radon concentration in groundwater samples varied in a wide range from below the detection limit of 18 pCi/L up to 1,100 pCi/L. A worldwide comparison of reported groundwater radon levels was conducted. Overall radon levels in Taiwan groundwater are relatively low compared to other countries because the geology of Taiwan is mainly comprised of sedimentary rocks. Among the 517 wells monitored, only five wells were found with radon concentrations higher than 500 pCi/L. These five wells are all located near the Chaochou Fault in the Pingtung Plain. This study suggests that well sites near the Chaochou Fault could be good locations to monitor radon anomalies for earthquake prediction and should be avoided for developing domestic water supply. In the recharge area near the Chaochou Fault, the radon concentration in groundwater from shallow wells was approximately 1/2 to 1/4 of that from deep wells in the same cluster.

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Resumen Se investigaron los niveles de radón en 517 pozos de monitoreo, construidos en las cinco mayores áreas de agua subterránea de Taiwan. La concentración de radón en las muestras de agua subterránea varía en un rango amplio, desde inferior al límite de detección que es 18 pCi/L hasta 1,100 pCi/L. Se realizó una comparación a escala mundial de los niveles de radón reportados en agua subterránea. En general los niveles de radón presente en el agua subterránea de Taiwan, son relativamente bajos comparados con otros países, puesto que la geología de Taiwan está compuesta de rocas sedimentarias. Entre los 517 pozos monitoreados, solamente en cinco se encontraron concentraciones de radón mayores a 500 pCi/L. Estos cinco pozos están todos localizados cerca de la falla ChaoChou en la Planicie de PingTung. El presente estudio sugiere que los pozos cercanos a la falla Chaochou, podrían ser buenos sitios para monitorear anomalías de radón para la predicción de terremotos y deberían evitarse para los desarrollos de abastecimiento de agua potable. En la zona de recarga cerca de la falla Chaochou, la concentración de radón en agua subterránea obtenida en pozos someros, fue aproximadamente de &frac; a &frac; de aquella en pozos profundos ubicados en el mismo sector.

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Résumé On a mesuré les taux de Rn dans 517 forages ouverts dans cinq aquifères majeures de Taiwan. Les concentrations en Rn couvrent un domaine très large, à partir de valeurs très basses, au dessous de la limite de détection de 18pCi/l jusquaux valeurs assez grandes de 1100pCi/l. On a mené une analyse comparative avec des valeurs mentionnées en littérature. Par report aux valeurs mesurées en autres pays, les concentrations en Rn en Taiwan sont asses basses, compte que la structure géologique de Taiwan est constituée surtout par des roches sedimentaires. On a trouvé des concentrations au desuss de 500pCi/l seulement en cinq de 517 forages investigués. Tous ces cinq forages se trouvent au voisinage de la faille de Chaochou dans la plaine de Pingtung. Cet étude suggere que les forages situés près de la faille de Chaochou peuvent bien monitoriser les anomalie de Rn pour la prédiction des séismes mais doivent être évités lorsqil sagit de lalimentation en eau potable. Dans la zone de recharge près de la faille de Chaochou les concentrations en Rn mesurées dans les puits peu profondes representent 1/2-1/4 de ceux mesurées dans les forages de profondeur.

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High albedos of low inclination Classical Kuiper belt objects     

M.J. Brucker  W.M. Grundy  J.R. Spencer  E.I. Chiang 《Icarus》2009,201(1):284-496

We present observations of thermal emission from fifteen transneptunian objects (TNOs) made using the Spitzer Space Telescope. Thirteen of the targets are members of the Classical population: six dynamically hot Classicals, five dynamically cold Classicals, and two dynamically cold inner Classical Kuiper belt objects (KBOs). We fit our observations using thermal models to determine the sizes and albedos of our targets finding that the cold Classical KBOs have distinctly higher visual albedos than the hot Classicals and other TNO dynamical classes. The cold Classicals are known to be distinct from other TNOs in terms of their color distribution, size distribution, and binarity fraction. The Classical objects in our sample all have red colors yet they show a diversity of albedos which suggests that there is not a simple relationship between albedo and color. As a consequence of high albedos, the mass estimate of the cold Classical Kuiper belt is reduced from approximately 0.01 M_⊕ to approximately 0.001 M_⊕. Our results also increase significantly the sample of small Classical KBOs with known albedos and sizes from 21 to 32 such objects.  相似文献