臺灣區域性降雨及乾旱特性之研究

Study on Regional Precipitation and Drought Characteristics of Taiwan

10.30061/CEB.200506.0008

李錦育(Chin-Yu Lee)；林家榮(Chia-Rung Lin)；劉文賢(Wen-Hsien Liu)

乾旱稽延 ； 豐枯比 ； 水熱指數 ； Drought lag ； Flood-drought ratio ； Water-heat index

作物、環境與生物資訊

2卷2期（2005 / 06 / 01）

157 - 166

繁體中文

本研究收集交通部中央氣象局所屬氣象站於1897~2003年觀測之氣象資料，取其降雨量及氣溫數據，針對臺灣地區降雨特性進行區域性統計分析。採用之研究方法，乃以各月降雨與當月降雨平均值之比例C值進行頻率分析，並求得各測站各月份乾旱稽延與其發生頻率P、豐枯比值及水熱指數。由結果得知，臺灣地區乾旱稽延有越往南，發生頻率愈高且稽延月數愈長之趨勢。各區域之豐枯比分析結果為：南部(7.5)、中部(4.0)、東部(2.2)、北部(1.2)。臺灣地區洪水期降雨量最大較差為646.2 mm，枯水期更高達1,099.6 mm。水熱指數分析結果則為：中部(799.9)、南部(476.8)、東部(386.8)及北部(310.2)，得知北部地區為最易發生乾旱之地區。

Rainfall and temperature data from 1897 to 2003 provided by Center Weather Bureau were used to analyze the regional precipitation and drought characteristics in Taiwan. The ratio of monthly precipitation to average monthly precipitation of the study period was designated as C, which value was then used to calculate monthly drought-lag and its frequency P, flood-drought ratio, and water-heat index. The droughtlag frequency was higher and duration was longer toward the south region of Taiwan. The results of flood-drought ratio analyses were as follows: 7.5 in south region, 4.0 in central region, 2.2 in east region, and 1.2 in north region. The greatest difference in rainfall was 646.2 mm for the flooding period and 1,099.6 mm for the drought period. The calculated water-heat index was 799.9 in the central, 476.8 in the south, 386.8 in the east, and 310.2 in the north. Results suggest that north region is the area most vulnerable to drought.