Spatiotemporal Variation Characteristics of Extreme Temperature Events in Hainan Province over the Past Four Decades

Qiuhao Yun ¹ Qiang Zhang ^2*

• ¹ College of Geography, Shanxi Normal University,, Taiyuan, China
• ² Key Laboratory of Arid Climatic Change and Reducing Disaster of Gansu Province, China Meteorological Administration, Lanzhou, China

Against the backdrop of global warming, the frequency and intensity of extreme weather events have been gradually increasing. Hainan Province is an important tropical agricultural production area in China, where extreme temperatures can significantly affect crop yields, quality, and the sustainable development of the agricultural economy. Studying the temporal and spatial patterns of extreme temperature events in Hainan Province provides a scientific basis for future prevention and control of meteorological disasters in the region, thereby safeguarding agricultural output value. In this study, based on observational data from 21 meteorological stations in Hainan Province between 1980 and 2022, eight extreme temperature indices were calculated using the RClimDex model, and the temporal and spatial characteristics of extreme temperature events were quantitatively analyzed employing linear fitting, Mann-Kendall mutation test, Morlet wavelet analysis, and principal component analysis. The results indicate that (1) in the time series, extreme temperature events in Hainan Province generally exhibit an increasing trend. (2) Spatially, the propensity rates of extreme temperature events at most stations in Hainan Province also demonstrate an increasing trend. Only two indices in Hainan Province, Maximum daily temperature of the year (TXx) and Number of days with the lowest temperature >20℃ (TR20), show upward mutations, both concentrated between 2000 and 2011. (3) In terms of cyclical changes, the extreme temperature indices in Hainan Province exhibit a short oscillatory cycle of approximately 4 years, a medium oscillatory cycle of 8-14 years, and a long oscillatory cycle of 16-20 years. Hainan Province is primarily influenced by changes in warm indicators, and the variation in each extreme temperature index is closely associated with the elevation of daily maximum temperatures, which constitutes the primary cause.