近日，比利时根特大学Petrova, Irina Y.和Miralles, Diego G等人报道，观测受限的预测实验显示，干旱期将长于预期。相关论文于2024年9月18日发表在《自然》杂志上。

研究人员表明，限制模型预测与新提出的紧急约束(EC)来限制模型预测，可以将全球最长年度干旱期(LAD))这一核心干旱指标预测的不确定性降低10-26%。经EC校正后的预测结果显示，与目前预测的“中档”或“高端”未来作用力情景相比，LAD的平均增幅将高出42-44%。这些结果意味着到本世纪末，全球陆地平均LAD可能比目前预计的长10天。

研究利用两代气候模型，进一步揭示了历史LAD偏差能影响预测LAD增加幅度的全球区域，并探讨了陆地—大气反馈在其中的作用。研究结果揭示了一些地区的社会和生态系统，可能面临比预期更高和更早的干旱风险，结果还指出了当前一代气候模型中存在偏差的可能机制。

据研究人员介绍，气候模型表明，世界许多地区的极端干旱将加剧。然而，人们对预测这些变化的幅度和时间的信心仍然很低，使得社会在很大程度上毫无准备。

附：英文原文

Title: Observation-constrained projections reveal longer-than-expected dry spells

Author: Petrova, Irina Y., Miralles, Diego G., Brient, Florent, Donat, Markus G., Min, Seung-Ki, Kim, Yeon-Hee, Bador, Margot

Issue&Volume: 2024-09-18

Abstract: Climate models indicate that dry extremes will be exacerbated in many regions of the world. However, confidence in the magnitude and timing of these projected changes remains low, leaving societies largely unprepared5,6. Here we show that constraining model projections with observations using a newly proposed emergent constraint (EC) reduces the uncertainty in predictions of a core drought indicator, the longest annual dry spell (LAD), by 10–26% globally. Our EC-corrected projections reveal that the increase in LAD will be 42–44% greater, on average, than ‘mid-range’ or ‘high-end’ future forcing scenarios currently indicate. These results imply that by the end of this century, the global mean land-only LAD could be 10days longer than currently expected. Using two generations of climate models, we further uncover global regions for which historical LAD biases affect the magnitude of projected LAD increases, and we explore the role of land–atmosphere feedbacks therein. Our findings reveal regions with potentially higher- and earlier-than-expected drought risks for societies and ecosystems, and they point to possible mechanisms underlying the biases in the current generation of climate models.

DOI: 10.1038/s41586-024-07887-y

Source: https://www.nature.com/articles/s41586-024-07887-y