Tropical countries, like Nigeria, depend on rainfall for agriculture, power generation, transportation and other economic activities. Drought will hinder the performance of these activities, hence, it poses a significant threat to the economy. Understanding fluctuations and structures in droughts will help in forecasting, planning and mitigating its impact on livelihoods. In this study, the multifractal properties of drought at four temporal scales were investigated over different locations across Nigeria. Drought was computed using the standardized precipitation index from monthly precipitation data from 1980 to 2010. Using multifractal detrended fluctuation analysis, meteorological drought was found to have multifractal properties at 1-, 6-, 12- and 24-month temporal scale. The generalized Hurst exponent of drought at different time-scale showed dependence on scaling exponent. Long-range correlations were found to be main source of multifractality at all temporal scales. The multifractal strength increases with increasing temporal scale except for a few locations. The range of spectrum width were found to be 0.306–0.464 and 0.596–0.993 at 1- and 24-month temporal scale, respectively. No significant trend was found in the degree of multifractality across different climatic zones of Nigeria.

中文翻译：

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热带地区不同时间尺度气象干旱的多重分形特征

尼日利亚等热带国家的农业、发电、交通和其他经济活动依赖降雨。干旱将阻碍这些活动的开展，因此对经济构成重大威胁。了解干旱的波动和结构将有助于预测、规划和减轻其对生计的影响。在这项研究中，对尼日利亚不同地点的四个时间尺度的干旱多重分形特性进行了调查。干旱是使用 1980 年至 2010 年每月降水数据的标准化降水指数计算的。使用多分形去趋势波动分析，发现气象干旱在 1、6、12 和 24 个月的时间尺度上具有多分形特性。不同时间尺度干旱的广义 Hurst 指数表现出对尺度指数的依赖性。发现长程相关性是所有时间尺度上多重分形的主要来源。除少数位置外，多重分形强度随着时间尺度的增加而增加。在 1 个月和 24 个月的时间尺度上，光谱宽度的范围分别为 0.306-0.464 和 0.596-0.993。尼日利亚不同气候带的多重分形程度没有显着趋势。分别。尼日利亚不同气候带的多重分形程度没有显着趋势。分别。尼日利亚不同气候带的多重分形程度没有显着趋势。