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    Please use this identifier to cite or link to this item: http://tkuir.lib.tku.edu.tw:8080/dspace/handle/987654321/94579

    Title: 應用HHT分析臺灣乾旱趨勢之研究
    Other Titles: Study of Taiwan drought trend using HHT
    Authors: 陳竑廷;Chen, Hung-Ting
    Contributors: 淡江大學水資源及環境工程學系碩士班
    張麗秋;Chang, Li-Chiu
    Keywords: 乾旱;乾旱趨勢;希爾伯特黃轉換;標準降雨指標;Drought;drought trend;Hilbert-Huang transform;HHT;SPI;The Standardized Precipitation Index
    Date: 2013
    Issue Date: 2014-01-23 14:47:25 (UTC+8)
    Abstract: 近年來全球氣候變遷的議題引起各界的關注,全球氣候變遷將對水資源有多方面的影響,如改變全球降雨在時空的分布不均趨勢更加顯著、改變水資源的供需情況等。由於乾旱受到一些氣候與非氣候因素所衝擊,本研究利用希爾伯特黃轉換(HHT)分析探討乾旱趨勢;HHT係將訊號資料經由經驗模態分解(EMD),隨時間振盪的資料將分解成多個本質模態函數(IMF),再以希爾伯特轉換(HT)分析獲得以時間-頻率-能量描述時序資料之物理意義;如此藉由HHT分析具有非線性與非穩態之降雨資料。
    In recent years, Climate change has become one of the most critical global issues. Global climate change impacts water resources in many ways: changing the temporal and spatial distribution of precipitation, changing the demand and supply of water resources. This study uses the Hilbert-Huang Transform (HHT) to investigate the drought trend. The HHT method, consisting of empirical mode decomposition (EMD) and Hilbert spectral analysis, for analyzing precipitation can reveal the nonlinear and non-stationary nature of this phenomenon. The EMD can decompose any time series into a collection of intrinsic mode functions (IMF) and Hilbert transform can obtain a physically meaningful time-frequency-energy description of a time series.
    In this study, HHT is used to analyze the trend of precipitation in dry seasons, maximum number of consecutive non-rainy days and standard precipitation index (SPI). There are four rain gauges (Taipei, Taichung, Tainan, Hualien) selected as representative gauges of four parts (north, central, south and east Taiwan) in Taiwan. The EMD provides a framework for both information fission and fusion. The fission approach extracts features from IMFs; and the fusion approach merges information from the IMFs. Through fission, fusion and HHT spectrum, the trend and variation points of data. The results show that the drought trends of Taipei, Taichung and Tainan are decreasing in recent years; while Hualien does not significantly have the drought trend.
    Appears in Collections:[水資源及環境工程學系暨研究所] 學位論文

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