Spatial and temporal evolution of heatwaves in Taiwan in a changing climate using multi-dimensional complementary ensemble empirical mode decomposition

Abstract

Recent decades have witnessed noticeable warming in highly developed cities. Taiwan, a densely populated island characterized by its monsoon-dominated climate and unique mountainous topography, has experienced an average temperature increase of 1.0–1.4 °C in the last century, significantly exceeding the global average. This research introduces the Multi-dimensional Complementary Ensemble Empirical Mode Decomposition (MCEEMD) algorithm, providing a novel approach for analyzing gridded climate data and uncovering spatiotemporal temperature patterns in Taiwan. This methodology offers valuable insights into the localized impacts of climate change. The spatiotemporal evolution of temperature from 1960 to 2020 is analyzed to estimate the warming trend associated with climate change. Essential factors related to the urban heat island (UHI) effect, which leads to temperature disparities between urban and rural areas, are also examined. Warming and the UHI effect are critical components of climate change, increasing the likelihood of extreme weather events in urban areas. The study investigates extreme weather events from 1960 to 2020, focusing on heatwaves. It projects changes in the frequency and duration of heatwaves for the mid (2046–2065) and late 21st century (2081–2100). Notably, Taipei experienced a warming trend exceeding 1.5°C in the 2010s, which was likely influenced by urbanization. Additionally, areas experiencing the sharpest increase in heatwave events (more than 1.5 events) by 2000 were predominantly in highly developed cities across northern and southern Taiwan. Further analysis under the RCP8.5 scenario suggests that, by the end of the 21st century, heatwave events could last for at least 20 days in many regions, with the potential to extend to nearly a month during the summer.