南京信息工程大学智海课题组报道了21世纪初北太平洋炸弹气旋的减弱。这一研究成果于2025年2月5日发表在《大气科学进展》杂志上。

炸弹气旋是一种快速增强的温带气旋，主要出现在中纬度地区。这些极端事件在北太平洋地区（NP）尤为频繁，造成了重大的社会和环境风险。目前，人们对NP上空炸弹气旋可变性的理解仍然有限。

研究人员以1980年以来的主要再分析资料集为主题，分析了多个NP炸弹气旋特征的变化。结果表明，进入21世纪以来，炸弹气旋的强度呈减弱趋势，表现为近地面最大风速显著降低、海平面最低气压增大、增强速度减缓。进一步分析表明，炸弹气旋的减弱趋势与最大850 hPa ready 增长率减小密切相关，主要是由30°N - 45°N纬带内垂直风切变的减少所驱动。

此外，研究结果表明，阿留申低压调节了中纬度NP上空的经向气温梯度，这一点得到了气候模型输出的证实。这种调制为阿留申低压影响低空斜压性及其炸弹气旋特性提供了途径。这些结果对未来预测NP上的炸弹气旋活动具有重要意义，有助于风险评估和减轻这些极端事件的影响。

附：英文原文

Title: Weakening of bomb cyclones over the North Pacific in the early 21st century

Author: Jiaxiang Gao, Rong-Hua Zhang, hai zhi

Issue&Volume: 2025-02-05

Abstract: Bomb cyclones are rapidly deepening extratropical cyclones predominantly found in mid-latitude regions. These extreme events are particularly frequent over the North Pacific (NP), posing significant societal and environmental risks. Currently, our understanding of the variability of bomb cyclones over the NP remains limited. This study analyzes the variations in multiple NP bomb cyclone characteristics from 1980 onward using four major reanalysis datasets. The results show an weakening trend of bomb cyclones since the beginning of the 21st century, which is characterized by significant reductions in maximum near-surface wind speeds, increases in minimum sea-level pressure, and slower deepening rates. Further analysis reveals that the observed weakening trend of bomb cyclones is closely linked to a reduction in maximum 850 hPa Eady Growth Rate, driven primarily by reduced vertical wind shear within the 30°N–45°N latitudinal band. Furthermore, our findings indicate that the Aleutian Low acts to modulate the meridional air temperature gradient over the mid-latitude NP, which is corroborated by climate model outputs. This modulation provides a pathway for the Aleutian Low to affect low-level baroclinicity and thus bomb cyclone characteristics. These results have important implications for future projections of bomb cyclone activity over the NP, aiding in risk assessment and mitigating the impacts of these extreme events.

DOI: 10.1007/s00376-025-4453-2

Source: http://www.iapjournals.ac.cn/aas/en/article/doi/10.1007/s00376-025-4453-2