Comparison of two bias correction methods for precipitation simulated with a regional climate model     

Tschöke  Gabriele Vanessa  Kruk  Nadiane Smaha  de Queiroz  Paulo Ivo Braga  Chou  Sin Chan  de Sousa Junior  Wilson Cabral 《Theoretical and Applied Climatology》2017,127(3-4):841-852

This study evaluates the performance of two bias correction techniques—power transformation and gamma distribution adjustment—for Eta regional climate model (RCM) precipitation simulations. For the gamma distribution adjustment, the number of dry days is not taken as a fixed parameter; rather, we propose a new methodology for handling dry days. We consider two cases: the first case is defined as having a greater number of simulated dry days than the observed number, and the second case is defined as the opposite. The present climate period was divided into calibration and validation sets. We evaluate the results of the two bias correction techniques using the Kolmogorov-Smirnov nonparametric test and the sum of the differences between the cumulative distribution curves. These tests show that both correction techniques were effective in reducing errors and consequently improving the reliability of the simulations. However, the gamma distribution correction method proved to be more efficient, particularly in reducing the error in the number of dry days.

  相似文献   

Uncertainty Reduction of Estimated Geostrophic Volume Transports with Altimeter Observations East of Taiwan   总被引：1，自引：0，他引：1  

Yih Yang  Cho-Teng Liu 《Journal of Oceanography》2003,59(2):251-257

The common geostrophic estimation of ocean current velocity uses only water temperature and conductivity profiles. The geostrophic volume transport of a western boundary current, like the Taiwan Current (Kuroshio east of Taiwan), between the coast and its eastern boundary can be easily estimated based on hydrographic survey data. But the eastern boundary of the Taiwan Current is very uncertain due to extremely variable hydrographic conditions. This uncertainty is strongly correlated with the propagating mesoscale eddies originating from the interior of the western North Pacific Ocean. The uncertainty of estimated transport can be greatly reduced if eddy distribution is considered when determining the integration boundaries with the assistance of satellite altimeter measurements. Eight hydrographic surveys east of Taiwan between November 1992 and June 1996 are demonstrated in this study. The average geostrophic transport of the Taiwan Current with a reference set to 1000 dbar at 22°N between the east coast of Taiwan and 124°E is 22.9 ±14.2 Sv and changes to 22.1 ± 8.3 Sv, the uncertainty of which is nearly halved after taking account of the eddy distribution. The estimation uncertainty is insensitive to vertical displacements of the reference level within the depth range between 800 and 2000 dbar. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Step Loading Compression of Ultra-Soft Soil under Radial Drainage Conditions     

Myint Win Bo  Kai Sin Wong  Victor Choa  Arul Arulrajah 《Marine Georesources & Geotechnology》2016,34(7):648-658

  相似文献   

Analysis of infiltration of 2D trickle irrigation under multiple‐line sources     

Jiann‐Mou Chen  Yih‐Chi Tan  Yu‐Zhang Wu 《水文研究》2008,22(14):2657-2666

The analysis of infiltration of 2D trickle irrigation under multiple‐line sources, governed by the celebrated Richards equation, is performed, aiming at determining the efficiency of trickle irrigation so as to reduce the water demand. A closed‐form solution is explicitly obtained by utilizing the Fourier integral transformation, and this serves as a means to compute the distribution of volumetric water content during trickle irrigation. Results for the infiltration of 2D trickle irrigation under single line and multiple‐line sources are presented, which illustrate the distribution of infiltration water that diffuses into the soil, and make it possible to calculate the period of time required for trickle irrigation for different plants. The results can be applied to verify complicated solutions from other numerical models. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Spectral decomposition of periodic ground water fluctuation in a coastal aquifer     

David Ching‐Fang Shih  Gwo‐Fong Lin  Yee‐Ping Jia  Yue‐Gau Chen  Yih‐Min Wu 《水文研究》2008,22(12):1755-1765

  相似文献   

Discussion of paper ‘Real‐time hybrid testing using the unconditionally stable explicit CR integration algorithm’ by Cheng Chen,James M. Ricles,Thomas M. Marullo and Oya Mercan,Earthquake Engineering and Structural Dynamics 2009; 38:23–44     

Shuenn‐Yih Chang 《地震工程与结构动力学》2012,41(5):1061-1063

  相似文献   

A two‐dimensional inverse model to identify transmissivity in an anisotropic aquifer     

Shih‐Ching Wu  Yih‐Chi Tan  Chu‐Hui Chen  Shien‐Tsung Lin  Kai‐Yuan Ke 《水文研究》2008,22(26):5086-5096

This study suggested a numerical model using the Tabu search algorithm along with the Adjoint State method to identify the hydrogeological characteristics of an anisotropic groundwater aquifer. The Tabu search algorithm was applied to identify the anisotropic transmissivity components to avoid a local optimum. Then, the Adjoint State method was used to calculate the sensitivity of the parameters in order to increase the efficiency of the optimization. For an anisotropic and homogeneous aquifer, results showed that the optimal procedure presented combining the Tabu search algorithm and the Adjoint State method might successfully identify the values of the transmissivity components. If the duration of the pumping test was long enough (12‐h pumping test), the value of the transmissivity components could be optimized with type‐curve, straight‐line, and Tabu search methods, along with the Adjoint State methods. If the duration of the pumping test was short (0·5‐h pumping test), the Tabu search method, along with the Adjoint State method proposed herein, might successfully optimize the transmissivity components. For an anisotropic but heterogeneous aquifer, results showed that the suggested optimal procedure still successfully identified the values of the transmissivity components. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

EDITORIAL: LESSONS IN GEOGRAPHY   总被引：2，自引：1，他引：1  

James D. Sidaway  Peggy Teo 《Singapore journal of tropical geography》2005,26(1):1-3

  相似文献   

Application of wavelet‐based multi‐model Kalman filters to real‐time flood forecasting     

Chien‐Ming Chou  Ru‐Yih Wang 《水文研究》2004,18(5):987-1008

This paper presents the application of a multimodel method using a wavelet‐based Kalman filter (WKF) bank to simultaneously estimate decomposed state variables and unknown parameters for real‐time flood forecasting. Applying the Haar wavelet transform alters the state vector and input vector of the state space. In this way, an overall detail plus approximation describes each new state vector and input vector, which allows the WKF to simultaneously estimate and decompose state variables. The wavelet‐based multimodel Kalman filter (WMKF) is a multimodel Kalman filter (MKF), in which the Kalman filter has been substituted for a WKF. The WMKF then obtains M estimated state vectors. Next, the M state‐estimates, each of which is weighted by its possibility that is also determined on‐line, are combined to form an optimal estimate. Validations conducted for the Wu‐Tu watershed, a small watershed in Taiwan, have demonstrated that the method is effective because of the decomposition of wavelet transform, the adaptation of the time‐varying Kalman filter and the characteristics of the multimodel method. Validation results also reveal that the resulting method enhances the accuracy of the runoff prediction of the rainfall–runoff process in the Wu‐Tu watershed. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

Abundance of epiphytic dinoflagellates from coastal waters off Jeju Island,Korea During Autumn 2009     

Hyung Seop Kim  Wonho Yih  Jong Hyeok Kim  Geumog Myung  Hae Jin Jeong 《Ocean Science Journal》2011,46(3):205-209

The occurrence of harmful epiphytic dinoflagellates is of concern to scientists, the aquaculture industry, and government due to their toxicity not only to marine organisms but also to humans. There have been no studies on the abundance of the epiphytic dinoflagellates in Korean waters. We explored the presence of epiphytic dinoflagellates in the coastal waters off Jeju Island, southwestern Korea. Furthermore, we measured the abundance of epiphytic dinoflagellates on the thalli of 24 different macroalgae, collected from five different locations in October 2009. Five epiphytic dinoflagellate genera Amphidinium, Coolia, Gambierdiscus, Ostreopsis, and Prorocentrum were found. These five genera were observed on the thalli of the macroalgae Chordaria flagelliformis, Martensia sp., Padina arborescens, and Sargassum sp., while none were observed exceptionally on Codium fragile. The abundance of Ostreopsis spp. was highest on Derbesia sp. (8,660 cells/g wet weight), while that of Gambierdiscus spp. was highest on Martensia sp. (4,870 cells/g-ww). The maximum abundances of Amphidinium spp., Coolia spp., and Prorocentrum spp. were 410, 710, and 300 cells/g-ww, respectively. The maximum abundance of Coolia spp., Gambierdiscus spp., and Ostreopsis spp. obtained in the present study was lower than for other locations reported in literature. The results of the present study suggest that the presence and abundance of epiphytic dinoflagellates may be related to the macroalgal species of the coastal waters of Jeju Island.  相似文献