Identification and spatiotemporal characteristics of compound extreme climate events in the Minjiang River Basin

Abstract

[Objective] With global warming, compound extreme climate events pose more significant adverse impacts on human development and ecological environments than single extreme climate events. [Methods] Based on daily average temperature and precipitation data from 29 meteorological stations in the Minjiang River Basin from 1980 to 2021, the percentile method(90th and 10th percentiles) was used to identify compound extreme climate events. The frequency, trend, and intensity of four types of compound extreme climate events(Warm-Dry, Warm-Wet, Cold-Dry, and Cold-Wet) in the Minjiang River Basin were analyzed. [Results] The result indicate that: 1) Warm-Dry events dominate the compound extreme events in the Minjiang River Basin, with the highest annual average frequency of 76.15 days. Cold-Dry events follow, with an annual average frequency of 53.32 days. On a seasonal scale, Warm-Dry events have the highest frequency, each exceeding 15 days. Cold-Dry events are most frequent in autumn and winter, each also exceeding 15 days. The frequencies of Warm-Wet and Cold-Wet events are relatively low. 2) Spatially, high-frequency areas of Warm-Wet and Warm-Dry events are located in the southern Jianxi Basin, eastern Futunxi and Shaxi Basins, and the eastern and northern middle-lower reaches of the Minjiang River Basin. Cold-Wet and Cold-Dry events mainly occur in the northern Jianxi Basin, western Futunxi and Shaxi Basins, and the southwestern middle-lower reaches of the Minjiang River Basin. 3) Warm-Dry events show a significant increasing trend, while Cold-Dry events exhibit a significant decreasing trend. Among sub-basins, the Shaxi Basin shows the most significant increasing trend for Warm-Dry events, at 13.58 days per decade, while the Futunxi Basin shows the most significant decreasing trend for Cold-Dry events, at-7.49 days per decade. 4) In terms of intensity, although Warm-Wet events have a lower frequency, they exhibit higher intensity, predominantly at strong and moderate levels, with more moderate-level days than strong-level days. Warm-Dry events also predominantly occur at strong and moderate levels, with more strong-level days than moderate-level days. [Conclusion] Overall, Warm-Dry events are the most prevalent in the Minjiang River Basin, with high intensity and an increasing trend. Cold-Dry events mainly occur in autumn and winter, with a decreasing trend. Under extreme precipitation impacts, Warm-Wet events exhibit high intensity but low frequency.

Keywords

extreme climate / compound events / frequency / trend / intensity / Minjiang River Basin / climate change / precipitation