The changing climatic patterns associated with intense and erratic rainfall have led to high flooding risk in urban areas. Identifying these hydro-meteorological risks in cities is a matter of concern for decision-makers. The present study investigates long-term rainfall variability and trend analysis in 11 coastal smart cities in India. A relatively new approach involving the Hilbert–Huang transform (HHT) method is used to identify long-term trends by investigating time-frequency characterization. The study shows that the rainfall trend with a periodicity of 12.5–15.6 years is significantly increasing for Panaji while decreasing for Thane during the southwest monsoon (SWM), even though both cities are located on the west coast of India and are mainly influenced by SWM. Further, the intensity of northeast monsoon (NEM) decreased in Chennai, while the influence of SWM has increased in recent decades. Thane shows a firm decreasing rainfall trend, which is alarming and potent among the studied cities. Subsequently, a detailed co-relation study investigates a link between the changing rainfall patterns and global climate indices. The results illustrate that the influence of climatic indices is highly dynamic city-wise. The present method is very efficient and effective for analyzing rainfall variability in the context of coastal urban areas.

中文翻译：

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使用 Hilbert Huang Transform 分析印度沿海智慧城市的降雨趋势和水文气候遥相关


与强降雨和不稳定降雨相关的气候模式变化导致城市地区发生洪水风险高。识别城市中的这些水文气象风险是决策者关心的问题。本研究调查了印度 11 个沿海智慧城市的长期降雨变化和趋势分析。使用一种涉及 Hilbert-Huang 变换 （HHT） 方法的相对较新的方法，通过研究时频特征来识别长期趋势。研究表明，在西南季风 （SWM） 期间，帕纳吉的 12.5-15.6 年周期性降雨趋势显着增加，而塔那的降雨趋势减少，尽管这两个城市都位于印度西海岸并且主要受 SWM 的影响。此外，钦奈东北季风 （NEM） 的强度有所下降，而 SWM 的影响在近几十年来有所增加。塔那显示出明显的降雨量减少趋势，这在研究的城市中是令人担忧和有效的。随后，一项详细的相互关系研究调查了不断变化的降雨模式与全球气候指数之间的联系。结果表明，气候指数的影响在城市方面是高度动态的。该方法对于分析沿海城市地区的降雨变化非常有效。