地球温暖化が北半球の極端降雨・降雪に与える影響を解明(Global Warming Reshapes Extreme Rainfall, Snowfall across Northern Hemisphere: Study)

2025-10-27 中国科学院(CAS)

中国科学院新疆生態地理研究所の研究チームは、過去70年間における北半球の極端降雨・降雪の変化を解析し、地球温暖化がそれらの発生様式を再構築していることを明らかにした。ERA5-Land再解析データ(1950〜2022年)を用いた解析の結果、極端降雨は年平均0.269mmの速度で増加し、極端降雪(0.029mm/年)の約9倍の速さで強度が高まっていることが判明。温暖化は主に降雨の極端化を促す一方、降雪への影響は限定的であった。中緯度地域では洪水リスク、高緯度や山岳地域では積雪・雪崩などの災害リスク対策が重要になると指摘している。本研究は、地域ごとの気候適応策や防災戦略設計に資する基礎知見を提供するものであり、『Advances in Climate Change Research』誌に掲載された。

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北半球における極端な降雨と降雪の対照的な傾向 Contrasting trends of extreme rainfall and snowfall in the Northern Hemisphere

Yu-Peng Li, Ya-Ning Chen, Fan Sun, Zhi Li, Gong-Huan Fang, Fei Wang, Xue-Qi Zhang, Bao-Fu Li
Advances in Climate Change Research  Available online: 22 September 2025
DOI:https://doi.org/10.1016/j.accre.2025.09.002

地球温暖化が北半球の極端降雨・降雪に与える影響を解明(Global Warming Reshapes Extreme Rainfall, Snowfall across Northern Hemisphere: Study)

Abstract

Global warming has modified the distribution between solid and liquid precipitation, leading to changes in the intensity and frequency of extreme rainfall and snowfall. However, the distinct response mechanisms of these extremes to warming remain underexplored at the global scale, particularly in regard to the drivers behind their contrasting trends. To address this gap, we conducted a hemispheric-scale analysis using the ERA5-Land reanalysis dataset (1950–2022) and quantified phase-specific intensification patterns across the Northern Hemisphere. According to the results, extreme rainfall is accelerating at a rate nine times higher (0.269 mm per year, p < 0.05) than that of extreme snowfall (0.029 mm per year, p > 0.05), as identified by the 90th percentile method, which highlights the differing thermal sensitivities of liquid and solid precipitation. This contrast becomes further evident in their temperature responses: extreme rainfall displays a marked increase with warming (2.27 mm/K), whereas extreme snowfall decreases (−1.63 mm/K), especially across mid-latitudes (30°–60°N). Notably, both types of extremes show increasing contributions to total precipitation (rainfall: +0.038% per year, p < 0.05; snowfall: +0.017% per year, p < 0.05), which indicates systemic shifts in precipitation regimes. Mechanistic analysis identified baseline snowfall magnitude and its temporal trend as dominant factors governing phase-specific intensification, with its spatial variability shaped by latitude, elevation and large-scale circulation patterns. This study offers novel insights into extreme precipitation dynamics from a phase-specific perspective.

1702地球物理及び地球化学
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