最近的欧洲干旱及其与普遍存在的大规模大气模式的联系
Sigrid J Bakke1,2, Monica Ionita3,4, Lena M Tallaksen5
1Department of Geosciences, University of Oslo, Oslo, Norway. sijb@nve.no.
Scientific reports
|December 11, 2023
概括
欧洲的干旱与大气压升高有关. 研究表明,增加的高压系统 (地势高度在500mb) 与更干燥的条件 (标准化降水-蒸发透气指数) 相相关,未来的预测表明这种趋势将继续.
科学领域:
- 大气科学 大气科学
- 气候科学 气候科学
- 气象学 天气学
背景情况:
- 近几十年来,欧洲经历了严重的干旱,特别是在2018年和2022年,造成了重大的社会,环境和经济破坏.
- 虽然大气循环和气象干旱之间的联系是公认的,但缺乏深入的研究,将历史干旱指数变化与欧洲大气大规模模式联系起来.
研究的目的:
- 调查大气大规模模式的历史变化与欧洲各地的气象干旱指标之间的关系.
- 分析在生长季节不同欧洲气候区域的500mb (Z500) 地势高度趋势和标准降雨-蒸发指数 (SPEI) 的趋势.
主要方法:
- 分析了北,西,中东和地中海气候地区的1979年至2021年的500mb (Z500) 地势高度和标准降雨-蒸发指数 (SPEI) 数据.
- 计算了Z500和SPEI之间的相关性和共发生情况,以评估高压系统和干旱之间的联系.
- 利用CMIP6气候模型在低端 (SSP126) 和高端 (SSP585) 排放场景下预测未来的Z500变化.
主要成果:
- 从1979年到2021年,西欧 (春季) 和中东欧 (夏季) 观察到Z500 (更高的压力) 增加和SPEI (更干燥的条件) 减少的显著趋势.
- 自1900年以来,通过显著的相关性和干旱和高压异常的高共发生率 (69-96%) 证实了Z500和SPEI之间的强烈联系.
- 未来的预测表明,异常高压系统将成为常态,在高排放场景下可能超过2018/2022年水平,尽管模型存在不确定性.
结论:
- 历史数据显示了欧洲大气循环的显著趋势,与观察到的干燥趋势有很强的相关性.
- 预计异常高压系统将变得更频繁,在整个欧洲增加干旱风险.
- 当前的气候模型 (CMIP6组合) 在准确地复制历史循环变化的空间异质性方面存在局限性,这导致未来干旱预测的不确定性.
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