Application of artificial neural networks in typhoon surge forecasting   总被引：1，自引：0，他引：1  

C.M. Tseng  C.D. Jan  J.S. Wang  C.M. Wang 《Ocean Engineering》2007,34(11-12):1757-1768

A typhoon-surge forecasting model was developed with a back-propagation neural network (BPN) in the present paper. The typhoon's characteristics, local meteorological conditions and typhoon surges at a considered tidal station at time t−1 and t were used as input data of the model to forecast typhoon surges at the following time. For the selection of a better forecasting model, four models (Models A–D) were tested and compared under the different composition of the above-mentioned input factors. A general evaluation index that is a composition of four performance indexes was proposed to evaluate the model's overall performance. The result of typhoon-surge forecasting was classified into five grades: A (excellent), B (good), C (fair), D (poor) and E (bad), according to the value of the general evaluation index. Sixteen typhoon events and their corresponding typhoon surges and local meteorological conditions at Ken–fang Tidal Station in the coast of north-eastern Taiwan between 1993 and 2000 were collected, 12 of them were used in model's calibration while the other four were used in model's verification. The analysis of typhoon-surge forecasting results at Ken–fang tidal station show that the Model D composing 18 input factors has better performance, and that it is a suitable BPN-based model in typhoon-surge forecasting. The Model D was also applied to typhoon-surge forecasting at Cheng-kung Tidal Station in south-eastern coast of Taiwan and at Tung-shih Tidal Station in the coast of south-western Taiwan. Results show that the application of Model D in typhoon-surge forecasting at Cheng-kung Tidal Station has better performance than that at Tung-shih Tidal Station.  相似文献   

Precise orbit determination for the FORMOSAT-3/COSMIC satellite mission using GPS   总被引：2，自引：1，他引：1  

Cheinway Hwang  Tzu-Pang Tseng  Tingjung Lin  Dražen Švehla  Bill Schreiner 《Journal of Geodesy》2009,83(5):477-489

The joint Taiwan–US mission FORMOSAT-3/ COSMIC (COSMIC) was launched on April 17, 2006. Each of the six satellites is equipped with two POD antennas. The orbits of the six satellites are determined from GPS data using zero-difference carrier-phase measurements by the reduced dynamic and kinematic methods. The effects of satellite center of mass (COM) variation, satellite attitude, GPS antenna phase center variation (PCV), and cable delay difference on the COSMIC orbit determination are studied. Nominal attitudes estimated from satellite state vectors deliver a better orbit accuracy when compared to observed attitude. Numerical tests show that the COSMIC COM must be precisely calibrated in order not to corrupt orbit determination. Based on the analyses of the 5 and 6-h orbit overlaps of two 30-h arcs, orbit accuracies from the reduced dynamic and kinematic solutions are nearly identical and are at the 2–3 cm level. The mean RMS difference between the orbits from this paper and those from UCAR (near real-time) and WHU (post-processed) is about 10 cm, which is largely due to different uses of GPS ephemerides, high-rate GPS clocks and force models. The kinematic orbits of COSMIC are expected to be used for recovery of temporal variations in the gravity field.  相似文献   

Late Cenozoic environmental change in southwestern Tibet: Evidence from stable isotopes     

WANG Yang  Sofia Khawaj  WANG Xiaoming  Benjamin Passey  ZHANG Chunfu  LI Qiang  Zhijie J. Tseng  Gary T. Takeuchi  DENG Tao  XIE Guangpu 《《地质学报》英文版》2013,87(Z1):875-875

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Application of GIS for the determination of hazard hotspots after direct transportation linkages between Taiwan and China     

Cheng-Wu Chen  Ching-Chung Lee  Chun-Pin Tseng  Chia-Hung Chen 《Natural Hazards》2013,66(2):191-228

A robust and reliable risk assessment procedure for the determination of transportation hazards between Taiwan and China needs to be developed. These hazards, which are related to mixed types of transport, including both air and maritime routes, play an important role in public security, and their effects need to be taken into consideration. After the implementation of direct cross-strait transportation, it has become necessary to master the spatial characteristics and distributions of maritime space policing cases and to plan effective control strategies in order to maintain public security. This study employs the Geographic Information System (GIS) technology to analyze the spatial locations of maritime cases that arose in the Taichung Harbor area from 2000 to 2010. The characteristics related to the spatial characteristics are surveyed, estimates are made utilizing the gathering and scattering model, hotspots are explored, and planned patrol and monitoring points drafted to provide assignment information for coastal patrol institutions.  相似文献   

An inter-hemispheric comparison of the tropical storm response to global warming     

Stephanie Gleixner  Noel Keenlyside  Kevin I. Hodges  Wan-Ling Tseng  Lennart Bengtsson 《Climate Dynamics》2014,42(7-8):2147-2157

Model studies do not agree on future changes in tropical cyclone (TC) activity on regional scales. We aim to shed further light on the distribution, frequency, intensity, and seasonality of TCs that society can expect at the end of the twenty-first century in the Southern hemisphere (SH). Therefore, we investigate TC changes simulated by the atmospheric model ECHAM5 with T213 (~60 km) horizontal resolution. We identify TCs in present-day (20C; 1969–1990) and future (21C; 2069–2100) time slice simulations, using a tracking algorithm based on vorticity at 850 hPa. In contrast to the Northern hemisphere (NH), where tropical storm numbers reduce by 6 %, there is a more dramatic 22 % reduction in the SH, mainly in the South Indian Ocean. While an increase of static stability in 21C may partly explain the reduction in tropical storm numbers, stabilization cannot alone explain the larger SH drop. Large-scale circulation changes associated with a weakening of the Tropical Walker Circulation are hypothesized to cause the strong decrease of cyclones in the South Indian Ocean. In contrast the decrease found over the South Pacific appears to be partly related to increased vertical wind shear, which is possibly associated with an enhanced meridional sea surface temperature gradient. We find the main difference between the hemispheres in changes of the tropical cyclones of intermediate strength with an increase in the NH and a decrease in the SH. In both hemispheres the frequency of the strongest storms increases and the frequency of the weakest storms decreases, although the increase in SH intense storms is marginal.  相似文献   

Derivation of internal solitary wave amplitude in the South China Sea deep basin from satellite images     

Guan-Yu Chen  Feng-Chun Su  Chi-Mong Wang  Cho-Teng Liu  Ruo-Shan Tseng 《Journal of Oceanography》2011,67(6):689-697

In the present study, theories based on the Korteweg–de Vries equation are extended to the Benjamin–Ono equation to allow the determination of internal solitary wave (ISW) amplitude from satellite images. The free surface flow induced by an ISW is derived for deep water. As a coherent structure, the amplitude of the ISW has a unique relation to the convergence/divergence of surface flow, such that the flow convergence/divergence will increase/decrease the backscattering cross section and generate bright/dark bands in satellite images. The distance between bright and dark bands can be related to the amplitude of ISW. To validate the theory, a multi-ship measurement made on 9–11 May 2005 during the spring tide period is used. A systematic approach to determine the thickness and density of the upper and lower layers is also included so that the free surface flow can be determined with a relatively high accuracy.  相似文献   

The evolution and trend of the traditional fishing rights     

Huan-Sheng Tseng  Ching-Hsiewn Ou 《Ocean & Coastal Management》2010,53(5-6):270-278

“Traditional fishing rights” were once universally accepted by the international community. However, under a regime of Exclusive Economic Zones (EEZs) defined by the United Nations Convention on the Law of the Sea (UNCLOS) in 1982, these rights were treated as a reasonable allocation of the surplus of the total allowable catch (TAC) or dependence on phase-out arrangements in bilateral fisheries agreements. This has caused the gradual marginalization of traditional fishing rights. This paper analyzes the transformations and trends affecting the development of fishing industries around the world, especially the growth and decline of traditional fishing rights and EEZs.  相似文献   

The impact of South Pacific extratropical forcing on ENSO and comparisons with the North Pacific   总被引：3，自引：0，他引：3  

Ruiqiang Ding  Jianping Li  Yu-heng Tseng 《Climate Dynamics》2015,44(7-8):2017-2034

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Multi-transmitter multi-receiver null coupled systems for inductive detection and characterization of metallic objects     

J. Torquil Smith  H. Frank Morrison  Lawrence R. Doolittle  Hung-Wen Tseng   《Journal of Applied Geophysics》2007,61(3-4):227-234

Equivalent dipole polarizabilities are a succinct way to summarize the inductive response of an isolated conductive body at distances greater than the scale of the body. Their estimation requires measurement of secondary magnetic fields due to currents induced in the body by time varying magnetic fields in at least three linearly independent (e.g., orthogonal) directions. Secondary fields due to an object are typically orders of magnitude smaller than the primary inducing fields near the primary field sources (transmitters). Receiver coils may be oriented orthogonal to primary fields from one or two transmitters, nulling their response to those fields, but simultaneously nulling to fields of additional transmitters is problematic. If transmitter coils are constructed symmetrically with respect to inversion in a point, their magnetic fields are symmetric with respect to that point. If receiver coils are operated in pairs symmetric with respect to inversion in the same point, then their differenced output is insensitive to the primary fields of any symmetrically constructed transmitters, allowing nulling to three (or more) transmitters. With a sufficient number of receivers pairs, object equivalent dipole polarizabilities can be estimated in situ from measurements at a single instrument sitting, eliminating effects of inaccurate instrument location on polarizability estimates. The method is illustrated with data from a multi-transmitter multi-receiver system with primary field nulling through differenced receiver pairs, interpreted in terms of principal equivalent dipole polarizabilities as a function of time.  相似文献   

Shared near neighbours neural network model: a debris flow warning system     

Fi‐John Chang  Kuo‐Yuan Tseng  Paulo Chaves 《水文研究》2007,21(14):1968-1976

The main purpose of this study is to develop a new type of artificial neural network based model for constructing a debris flow warning system. The Chen‐Eu‐Lan river basin, which is located in Central Taiwan, is assigned as the study area. The creek is one of the most well‐known debris flow areas where several damaging debris flows have been reported in the last two decades. The hydrological and geological data, which might have great influence on the occurrence of debris flows, are first collected and analysed, then, the shared near neighbours neural network (SNN + NN) is presented to construct the debris flow warning system for the watershed. SNN is an unsupervised learning method that has the advantage of dealing with non‐globular clusters, besides presenting computational efficiency. By using SNN, the compiled hydro‐geological data set can easily and meaningfully be clustered into several categories. These categories can then be identified as ‘occurrence’ or ‘no‐occurrence’ of debris flows. To improve the effectiveness of the debris flow warning system, a neural network framework is designed to connect all the clusters produced by the SNN method, whereas the connected weights of the network are adjusted through a supervised learning method. This framework is used and its applicability and practicability for debris flow warning are investigated. The results demonstrate that the proposed SNN + NN model is an efficient and accurate tool for the development of a debris flow warning system. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献