Study on Impact of Watershed QPE Error to River Stage Simulation

• Main Authors: Jhih-Peng Jiang, 江志鵬
• Other Authors: 張哲豪
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/8mq99q

碩士 === 國立臺北科技大學 === 土木與防災研究所 === 100 === The current/forecasting water level can be calculated through the connection between instant hydrology and meteorology observation or data forecasting and hy-drologic/hydraulic simulation models in the flood prevention and precaution tech-nology at the present stage, such as the online “Flood Early Warning System" pro-vided by the Water Resources Agency. As for the forecasting accuracy, the change in the water level within one hour of the reading being submitted from forecasting stations with the highest readings can fall in the range of 20 to 50 centimeters, but the accuracy of some of the forecasting stations is awaiting improvement. The fac-tors that may influence the accuracy primarily comes from the process of water level forecasting patterns and the input factors like hydrographic and meteorology obser-vation and forecasting data. This study plans to use the factors to build up a error analytic process to water level simulation in order to create a threshold for evaluat-ing the impact of water level forecasting patterns in the future. In order to control the high variability of hydrographic and meteorology data from the forecasting, within the countries which carry out flood prevention forecasts, all adopt the combination of a variety of hydrographic and meteorology data of their resources in order to increase the reliability of the calculation and to forecast the hydrology. Due to the differences in outputting format and space and time dimen-sions between multiple types of data, there will be some problems when facing inte-gration. Therefore, this study divides bias analyzing processes into the sensitivity of precipitation observation and the uncertainty of precipitation forecasting. In hydrographic and meteorology data processing, the study analyzes the vari-ants to space transforming, interpolation and number accuracy in the observation of precipitation number analysis, and tries to evaluate the the sensitivity of water level calculations of space and precipitation observation reactions. In considering the un-certainty of precipitation forecasting itself, this study adopts the Monte Carlo Algo-rithm to simulate Quantitative Precipitation Forecasts for the precipitation cases of Typhoon KALMAEGI, 2008 and FANAPI, 2010, to analyze the impact of simulat-ing Quantitative Precipitation Forecasts to water level forecasting patterns.