天山山脈における極端降水に対する気象要因の季節的タイムラグ効果を解明 (Study Reveals Seasonal Time-lag Effects of Meteorological Factors on Extreme Precipitation in Central Asia’s Tienshan Mountains)

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2025-03-03 中国科学院(CAS)

中国科学院の新疆生態地理研究所(XIEG)の陳彦寧教授らの研究チームは、中央アジアの天山山脈(TMCA)における極端降水(EP)指数と気象要素および大気信号の時間遅れ効果を明らかにしました。長期的な気象データを用いてEP指数を生成し、部分相関やウェーブレットコヒーレンスなどの分析手法を適用して、EPの季節変動と時間遅れ特性を調査しました。その結果、EP指数には明確な季節的差異があり、夏にピーク値を示し、冬に低値を示すことが分かりました。さらに、気温と水蒸気量は、それぞれ春と夏においてEPに対して最も短い時間遅れ期間を持つことが判明しました。また、これらの時間遅れ効果の主な要因として、北半球亜熱帯高気圧強度、太陽フラックス、NINO B領域の海面水温異常、そして大西洋数十年変動が特定されました。この研究は、気候変動の中でのTMCAにおける時間遅れ効果の理解を深め、災害予防と緩和戦略の策定に重要な理論的支援を提供します。

<関連情報>

中央アジアの天山山脈における異常降水の気候要因駆動型タイムラグ効果 Climatic factor-driven time-lag effects of extreme precipitation in the Tienshan Mountains of Central Asia

Yihan Wang, Yaning Chen, Zhi Li, Gonghuan Fang, Chuan Wang, Xueqi Zhang, Yupeng Li, Yubo Guo
Journal of Hydrology  Available online: 22 February 2025
DOI:https://doi.org/10.1016/j.jhydrol.2025.132902

Highlights

  • The time-lag effects of climatic factors on extreme precipitation have seasonal differences.
  • The interaction between climate factors and extreme precipitation indices is most obvious in the 8–16 month period.
  • The interaction of multiple teleconnection factors affects the time-lag effects.
  • The model’s explanatory power improves considerably after accounting for all factors affecting the time lag.

Abstract

Global warming is disrupting the natural balance of ecosystems in the Tienshan Mountains of Central Asia (TMCA), leading to an increase in extreme precipitation (EP) events. However, the process of remote correlation between EP and climatic factors in the TMCA is not yet fully elucidated. This study employs partial correlation analysis, wavelet coherence and elastic net regression to explore the seasonal fluctuation characteristics of EP, systematically studies the spatio-temporal differentiation of temperature, water vapor content and teleconnection factors on the time-lag effect of EP, and evaluates the explanatory power of different influencing factors on the time-lag effect. Most EP indices were higher in summer and lower in winter during the study period (1951 to 2015). Furthermore, the time lag associated with temperature was shortest in spring (3-month lag), while that associated with water vapor content was shortest in summer (1-month lag). The Northern Hemisphere Subtropical High Intensity (NSI) and Solar Flux (SF) were the main drivers in both spring and summer, while the NINO B area sea surface temperature anomaly (NINOB) and the Atlantic Multidecadal Oscillation (AMO) were significant in summer and autumn. In winter, the influences of AMO and SF were more widespread. The model’s explanatory power improved significantly after incorporating all factors affecting the time lag. These findings have important implications for analyzing the dynamic response process between EP and climatic factors.

1702地球物理及び地球化学
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