灰预测推估干旱重现频率——以台湾西南部为例

近年来台湾西南部地区的干旱缺水事件已由每隔数年出现一次的发生频率，转变为几乎每年发生水资源严重匮乏窘况，换言之，即西南部地区降雨量在时空分布上越来越不平均。本文以台湾西南部地区为主要分析对象，利用灰预测模式，预测未来在气候变迁条件下特定时距内发生干旱的频率，提供不同用水者及早拟定旱灾应变措施以降低灾损。由研究结果得知：发生干旱系以每隔3—5年后重现频率再发生，故有效的水资源规划是必需的；另外，以模式精度检定，无论是平均残差模式精度检定或MAPE，皆显示四点建模预测较为准确，此结论可作为未来不同标的用水者推估的参考。

Grey Prediction to Estimate the Recurrence Frequency of Drought in the Southwestern Area of Taiwan

In recent years, occurrence frequencies of drought and water shortage disasters in the south - western part of Taiwan have changed from once every few years to almost once a year. In other words, the temporal and spatial dis- tributions of rainfall were more and more uneven of this region. For this reason, this article will focus on the areas in southwestern Taiwan as the main analysis object, to predict the drought frequency within a specific interval under the climate variation conditions in the future, and help the water users with different objectives prepare the drought contin- gency measures so as to reduce disaster losses. According to the results, the droughts were reproduced in the frequency of recurrence every 3 -5 years, so it is necessary to have the effective water resource planning. In addition, by using model accuracy to test, no matter the average residual mode system accuracy test or MAPE, the results show that the four points modeling for prediction is more accurate. This conclusion may be used as the future reference for the esti- mation by water users with different objectives.